Dnvgl-ru-ship-pt5.pdf

RULES FOR CLASSIFICATION Ships Edition July 2017 Amended January 2018

Part 5 Ship types Chapter 1 Bulk carriers and dry cargo ships

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS July 2017

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the July 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.1. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Amendments January 2018. Topic

Reference

Add missing variable and change variable name in Sec.5 [7.2.8].

Sec.5 [7.2.8]

Description In the formula for the static and dynamic force Fc-z the missing variable lp has been added and the variable BTop corrected.

Changes July 2017, entering into force 1 January 2018. Topic Application of global FEA for general dry cargo ships and multi-purpose dry cargo ships.

Reference

Description

Sec.5

Reduction of permissible still water bending moment and shear force for harbour condition, to comply with the acceptance criteria for AC-I according to Pt.3 Ch.1 Sec.2 Table 1 and Pt.3 Ch.7 Sec.3 Table 1.

Sec.5

Modification of lp and introduction of Δ Z for application of formula in Sec.5 [7.2.7] and Sec.5 [7.2.8].

Sec.5 [5.2.3]

Aligned with update in Pt.3 Ch.5 Sec.2 [2.3.1].

Sec.5 Table 2

Use of 10 probability level for ULS and correct speeds. In alignment with Pt.3 Ch.1 Sec.2 [5.3.2] and Pt.3 Ch.1 Sec.2 [5.3.3].

Sec.5 [7.1.6]

Consideration of all loading conditions with an equal fraction results in a more realistic fatigue life more in line with Pt.3 Ch.9 Sec.4 [3].

Sec.5 [7.1.7]

Alignment of the acceptance criteria with the 10

-8

-8

probability level.

Sec.5 [7.1.8] Sec.5 [7.2.6] Sec.5 [7.2.7]

Introduced simplified approach by which shear pressures or forces in longitudinal can be ignored.

Sec.5 [7.2.8] Sec.5 [7.2.7] Sec.5 [7.2.8]

Sec.5 [7.3] Correction of design load Sec.3 [3.2.1] sets table.

Introduced requirement to consider the tipping moment, generated by cargo resting on hatch covers, in both assessment of cargo hold and FEA, for consistency between these. Introduced requirement to consider more realistic forces on hatch covers on weather deck. Deleted paragraph describing embedded cargo hold analysis. Changed Sec.3 Table 3 to match static load conditions with the correct load scenario definition and acceptance criteria.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 3

Part 5 Chapter 1 Changes - current

CHANGES – CURRENT

Correction of stiffener length applied for section modulus requirements.

Reference Sec.3 Table 4

Description

Part 5 Chapter 1 Changes - current

Topic

Replaced l with lbdg in calculation of coefficient K3

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 4

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................. 12 1 Introduction.......................................................................................12 1.1 Introduction................................................................................... 12 1.2 Scope............................................................................................ 12 1.3 Application..................................................................................... 12 2 Class notations.................................................................................. 12 2.1 Ship type notations.........................................................................12 2.2 Additional notations........................................................................ 13 3 Definitions..........................................................................................14 3.1 Terms............................................................................................ 14 4 Documentation...................................................................................15 4.1 Documentation requirements............................................................15 5 Certification....................................................................................... 17 5.1 Certification requirements................................................................ 17 6 Testing............................................................................................... 18 6.1 Testing during newbuilding...............................................................18 Section 2 Common requirements.......................................................................... 19 1 Introduction.......................................................................................21 1.1 Introduction................................................................................... 21 1.2 Scope............................................................................................ 21 1.3 Application..................................................................................... 21 2 Structural design principles............................................................... 21 2.1 Structural arrangement - double side structure...................................21 2.2 Structural arrangement - single side structure.................................... 22 2.3 Structural arrangement - deck structure............................................ 23 2.4 Structural arrangement - plane bulkheads......................................... 23 2.5 Detailed design...............................................................................23 3 Pressures and forces due to dry bulk cargo.......................................23 3.1 Application..................................................................................... 23 3.2 Hold definitions...............................................................................23 3.3 Dry cargo characteristics................................................................. 25 3.4 Dry bulk cargo pressures.................................................................32 3.5 Shear load..................................................................................... 32 4 Design load scenarios........................................................................ 33

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 5

Part 5 Chapter 1 Contents

CONTENTS

4.2 Additional principal design load scenarios for dry cargo ships................ 34 5 Hull local scantling............................................................................ 36 5.1 Design load sets for ships intended to carry dry bulk cargo.................. 36 5.2 Cargo hold side frames of single side skin construction........................ 40 6 Water ingress alarms and drainage of forward spaces...................... 41 6.1 Water ingress alarms in dry cargo ships carrying dry cargo in bulk.........41 6.2 Water ingress alarms in single hold cargo ships.................................. 42 6.3 Availability of pumping systems........................................................43 Section 3 Steel coil requirements......................................................................... 44 1 Introduction.......................................................................................45 1.1 Introduction................................................................................... 45 1.2 Scope............................................................................................ 45 1.3 Application..................................................................................... 45 2 Steel coil loads in cargo holds........................................................... 45 2.1 General..........................................................................................45 2.2 Total loads..................................................................................... 48 2.3 Static loads.................................................................................... 49 2.4 Dynamic loads................................................................................ 50 3 Hull local scantling............................................................................ 51 3.1 General..........................................................................................51 3.2 Load application..............................................................................51 3.3 Inner bottom..................................................................................52 3.4 Hopper tank and inner hull.............................................................. 53 Section 4 Enhanced flooded requirements............................................................ 54 1 Introduction.......................................................................................55 1.1 Introduction................................................................................... 55 1.2 Scope............................................................................................ 55 1.3 Application..................................................................................... 55 2 Hull girder loads, pressures and forces due to dry cargoes in flooded conditions................................................................................ 56 2.1 Vertical still water hull girder loads................................................... 56 2.2 Vertically corrugated transverse watertight bulkheads..........................56 2.3 Double bottom in cargo hold region in flooded conditions..................... 62 3 Transverse vertically corrugated watertight bulkheads separating cargo holds in flooded condition.......................................................... 63 3.1 Structural arrangement....................................................................63 3.2 Net thickness of corrugation............................................................ 64

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 6

Part 5 Chapter 1 Contents

4.1 General..........................................................................................33

3.4 Net section modulus at the lower end of the corrugations.................... 67 3.5 Supporting structure in way of corrugated bulkheads...........................70 3.6 Upper and lower stool subject to lateral flooded pressure..................... 71 3.7 Corrosion addition...........................................................................71 4 Allowable hold loading in flooded conditions..................................... 71 4.1 Evaluation of double bottom capacity and allowable hold loading........... 71 5 Vertical hull girder bending and shear strength in flooded conditions............................................................................................. 75 5.1 Vertical hull girder bending strength..................................................75 5.2 Vertical hull girder shear strength of bulk carriers............................... 76 5.3 Vertical hull girder shear strength of ore carriers................................ 76 5.4 Hull girder ultimate strength check................................................... 77 Section 5 General dry cargo ships and multi-purpose dry cargo ships.................. 78 1 Introduction.......................................................................................79 1.1 Introduction................................................................................... 79 1.2 Scope............................................................................................ 79 1.3 Application..................................................................................... 79 2 General arrangement design............................................................. 79 2.1 General..........................................................................................79 2.2 Freeboard...................................................................................... 79 2.3 Double side skin construction........................................................... 79 2.4 Double side width........................................................................... 80 3 Structural design principles............................................................... 80 3.1 Corrosion protection of void double side skin spaces............................80 3.2 Structural arrangement....................................................................80 4 Loads................................................................................................. 81 4.1 Standard design loading conditions................................................... 81 4.2 Loading conditions for primary supporting members............................ 81 5 Hull girder strength........................................................................... 89 5.1 Vertical hull girder bending strength..................................................89 5.2 Vertical hull girder shear strength..................................................... 89 5.3 Loading instrument......................................................................... 91 6 Hull local scantling............................................................................ 92 6.1 Plating........................................................................................... 92 6.2 Stiffeners....................................................................................... 92 6.3 Primary supporting members........................................................... 92 6.4 Intersection of stiffeners and primary supporting members.................. 92

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 7

Part 5 Chapter 1 Contents

3.3 Bending, shear and buckling check................................................... 66

7 Finite element analysis...................................................................... 93 7.1 Global strength analysis.................................................................. 93 7.2 Cargo hold analysis.........................................................................95 7.3 Embedded cargo hold analysis..........................................................97 8 Buckling............................................................................................. 98 8.1 Hull girder buckling.........................................................................98 9 Fatigue............................................................................................... 98 9.1 General..........................................................................................98 9.2 Prescriptive fatigue strength assessment........................................... 98 Section 6 Bulk carriers.......................................................................................... 99 1 Introduction.......................................................................................99 1.1 Introduction................................................................................... 99 1.2 Scope............................................................................................ 99 1.3 Application..................................................................................... 99 2 Hull strength and arrangement....................................................... 100 2.1 CSR Bulk carriers.......................................................................... 100 2.2 Non-CSR Bulk carriers................................................................... 100 Section 7 Ore carriers......................................................................................... 101 1 Introduction..................................................................................... 101 1.1 Introduction..................................................................................101 1.2 Scope.......................................................................................... 101 1.3 Application................................................................................... 101 2 General arrangement design........................................................... 102 2.1 Forecastle.....................................................................................102 2.2 Access arrangement...................................................................... 103 3 Structural design principles............................................................. 103 3.1 Corrosion protection of wing void spaces..........................................103 3.2 Structural arrangement - cargo hold region...................................... 103 3.3 Structural arrangement - fore peak structure....................................104 3.4 Structural arrangement - machinery space....................................... 104 4 Loads............................................................................................... 105 4.1 Standard design loading conditions................................................. 105 4.2 Loading conditions for primary supporting members.......................... 105 5 Hull girder strength......................................................................... 105 5.1 Vertical hull girder shear strength................................................... 105 5.2 Hull girder yield check................................................................... 110

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 8

Part 5 Chapter 1 Contents

6.5 Fixed cargo securing devices............................................................ 92

6.1 Minimum thickness........................................................................112 6.2 Plating......................................................................................... 112 6.3 Stiffeners..................................................................................... 112 6.4 Primary supporting members..........................................................113 6.5 Intersection of stiffeners and primary supporting members................. 113 7 Finite element analysis.................................................................... 113 7.1 Cargo hold analysis....................................................................... 113 8 Buckling........................................................................................... 114 8.1 Hull girder buckling....................................................................... 114 9 Fatigue............................................................................................. 114 9.1 General........................................................................................ 114 9.2 Prescriptive fatigue strength assessment..........................................114 10 Cargo hatch covers and hatch coamings........................................114 10.1 General...................................................................................... 114 Section 8 Ships specialised for the carriage of a single type of dry bulk cargo.... 115 1 Introduction..................................................................................... 115 1.1 Introduction..................................................................................115 1.2 Scope.......................................................................................... 115 1.3 Application................................................................................... 115 2 General arrangement design........................................................... 115 2.1 Compartment arrangement............................................................ 115 3 Structural design principles............................................................. 116 3.1 Structural arrangement.................................................................. 116 4 Loads............................................................................................... 116 4.1 Standard design loading conditions................................................. 116 4.2 Loading conditions for primary supporting members.......................... 116 5 Hull girder strength......................................................................... 116 5.1 Loading manual and loading instrument...........................................116 6 Hull local scantling.......................................................................... 117 6.1 Minimum thickness........................................................................117 6.2 Plating......................................................................................... 117 6.3 Stiffeners..................................................................................... 117 6.4 Primary supporting members..........................................................117 6.5 Intersection of stiffeners and primary supporting members................. 117 7 Finite element analysis.................................................................... 117 7.1 Cargo hold analysis....................................................................... 117 8 Buckling........................................................................................... 118

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 9

Part 5 Chapter 1 Contents

6 Hull local scantling.......................................................................... 112

9 Fatigue............................................................................................. 118 9.1 General........................................................................................ 118 9.2 Prescriptive fatigue strength assessment..........................................118 Section 9 Great lakes bulk carriers..................................................................... 119 1 Introduction..................................................................................... 119 1.1 Introduction..................................................................................119 1.2 Scope.......................................................................................... 119 1.3 Application................................................................................... 119 2 General arrangement design........................................................... 119 2.1 Subdivision arrangement................................................................119 3 Structural design principles............................................................. 120 3.1 Corrosion additions........................................................................120 3.2 Structural arrangement.................................................................. 120 4 Loads............................................................................................... 120 4.1 General........................................................................................ 120 4.2 Standard design loading conditions................................................. 120 4.3 Loading conditions for primary supporting members.......................... 120 5 Hull girder strength......................................................................... 121 5.1 Vertical hull girder shear strength................................................... 121 5.2 Hull girder yield check................................................................... 121 5.3 Hull girder ultimate strength check................................................. 121 6 Hull local scantling.......................................................................... 121 6.1 Plating......................................................................................... 121 6.2 Stiffeners..................................................................................... 121 6.3 Primary supporting members..........................................................121 6.4 Intersection of stiffeners and primary supporting members................. 121 7 Finite element analysis.................................................................... 122 7.1 Cargo hold analysis....................................................................... 122 8 Buckling........................................................................................... 122 8.1 Hull girder buckling....................................................................... 122 9 Fatigue............................................................................................. 122 9.1 General........................................................................................ 122 10 Special requirements..................................................................... 122 10.1 Bow impact................................................................................ 122 10.2 Bottom slamming........................................................................ 123 10.3 Stern slamming...........................................................................123 11 Hull equipment, supporting structures and appendages................ 123

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 10

Part 5 Chapter 1 Contents

8.1 Hull girder buckling....................................................................... 118

11.2 Supporting structure for deck equipment and fittings....................... 123 11.3 Bulwark and protection of crew.....................................................123 12 Openings and closing appliances................................................... 124 12.1 General...................................................................................... 124 12.2 Small hatchways and weathertight doors........................................124 12.3 Cargo hatch covers/coamings and closing arrangements...................124 12.4 Side, stern and bow doors/ramps..................................................125 12.5 Tank access, ullage and ventilation openings...................................125 12.6 Machinery space openings............................................................ 125 12.7 Scuppers, inlets and discharges.................................................... 125 12.8 Freeing ports.............................................................................. 126 13 Stability..........................................................................................126 13.1 General...................................................................................... 126 Changes – historic.............................................................................................. 127

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 11

Part 5 Chapter 1 Contents

11.1 Anchoring and mooring equipment................................................ 123

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2].

1 Introduction 1.1 Introduction These rules apply to ships intended for carriage of various dry cargoes.

1.2 Scope The rules in this chapter give requirements for hull strength and equipment, including: — general requirements given in this section are applicable to all ship types listed in Table 1 — common requirements given in Sec.2 are in general applicable to all ship types listed in Table 1. For ships assigned the ship type notation Bulk carrier (with CSR) only requirements given in Sec.2 [6.1] and Sec.2 [6.3] are applicable — steel coil requirements given in Sec.3 are applicable to all ships, except from Bulk carrier (with CSR), loaded by steel coils on wooden dunnage — enhanced flooded requirements given in Sec.4 are applicable to ships assigned ship type notation Ore carrier or Bulk carrier (without CSR), complying with criteria further given in Sec.4 [1.3] — ship type specific requirements are given in Sec.5 to Sec.9 for ship types listed in Table 1.

1.3 Application The requirements in this chapter are supplementary to those given in Pt.2, Pt.3 and Pt.4 that are applicable for the assignment of main character of class.

2 Class notations 2.1 Ship type notations Vessels built in compliance with the requirements as specified in Table 1 will be assigned one of the class notations as follows: Table 1 Ship type notations

Class notation General dry cargo ship

Description 1)

Multi-purpose dry cargo ship Bulk carrier Ore carrier X carrier

3)

4)

5)

2)

Design requirements, rule reference

carriage of unitized and dry bulk cargo

Sec.5

carriage of unitized and dry bulk cargo

Sec.5

carriage of dry bulk cargo

Sec.6

carriage of ore cargo in dry bulk

Sec.7

ships specialised for the carriage of a single type of dry bulk cargo

Sec.8

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 12

Part 5 Chapter 1 Section 1

SECTION 1 GENERAL

Great lakes bulk carrier

Design requirements, rule reference

Description 6)

carriage of dry bulk cargo

Sec.9

1)

Mandatory for ships occasionally carrying dry cargo in bulk, unless ship type notation Multi-purpose dry cargo ship is assigned.

2)

Mandatory for ships occasionally carrying dry cargo in bulk, unless ship type notation General dry cargo ship is assigned.

3)

Mandatory for sea-going single deck ships with cargo holds of single and or double side skin construction, with a double bottom, hopper side tanks and top-wing tanks fitted below the upper deck, and intended for the carriage of solid bulk cargoes. Also mandatory for ships primarily intended for the carriage of solid bulk cargoes with other arrangements.

4)

Mandatory for sea-going single deck ships having two longitudinal bulkheads and a double bottom throughout the cargo region, and intended for carrying ore cargoes in the centre hold only.

5)

Mandatory, unless ship type notation Bulk carrier is assigned. X denotes the type of bulk cargo to be carried, limited to either Woodchips, Cement, Fly ash or Sugar.

6)

Designed to operate within the limits of the Great Lakes and St. Lawrence river to the seaward limits defined by the Anticosti Island.

2.2 Additional notations 2.2.1 The following additional notations, as specified in Table 2, are typically applied to dry cargo ships: Table 2 Additional notations Class notation

Description

Application

CSR

ships designed and built according to IACS common structural rules

mandatory for Bulk carrier with L ≥ 90 m and cross section in accordance with Sec.6 Figure 1

BC

strengthened for heavy cargo in bulk

mandatory for Bulk carrier (with CSR) with L ≥ 150 m mandatory for ships with: — LLL ≥ 150 m and bulk density

Grab

strengthened for grab loading and unloading

ρc ≥ 1.0 t/m3

— BC(A) or BC(B) — HC(A), HC(B*) or HC(B) — HC(M) with

ρc ≥ 1.0 t/m3

— OC(M) or OC(H) Strengthened

strengthened for heavy cargo

all ships

HL

tanks or holds strengthened for heavy liquid

all ships mandatory for:

HC

strengthened for heavy cargo in bulk

— General dry cargo ship or Multi-purpose dry cargo ship with L ≥ 150 m and minimum five cargo holds — Bulk carrier (without CSR) with L ≥ 150 m

OC

mandatory for Ore carrier with L ≥ 150 m

strengthened for ore cargo

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 13

Part 5 Chapter 1 Section 1

Class notation

Description

Application

Plus

extended fatigue analysis of ship details

all ships

CSA

direct analysis of ship structures

all ships

EL

easy loading of cargo holds

may be applied to Ore carriers

Container

equipped for carriage of containers

for ships other than Container ships

Crane

crane on board

all ships except from Crane vessel

DG

arranged for carriage of dangerous goods

all ships

SAFELASH

increased stevedores’ safety engaged in container handling

may be applied to ships with Container notation

ESP

ships subject to an enhanced survey programme

mandatory for Ore carriers and Bulk carriers

CMON

construction monitoring of hull critical locations

all ships

RO/RO

Designed and arranged for roll-on and roll-of cargo handling and transportation of rolling vehicles.

Multi-purpose dry cargo ship with additional purpose of loading/unloading roll-on and roll-off cargo in dedicated RO/RO space.

For a full definition of all class additional notations, see Pt.1 Ch.2.

3 Definitions 3.1 Terms Table 3 Definitions Terms

Definition

double side skin

Configuration where each ship side is constructed by the side shell and a longitudinal bulkhead connecting the double bottom and the deck. Hopper side tanks and topside tanks may, where fitted, be integral parts of the double side skin configuration.

long centre cargo hold

cargo hold having a length not less than 50% of the total length of the cargo hold region

ships occasionally carrying dry cargo in bulk

ships with minimum one seagoing loading condition with dry cargo in bulk specified in the loading manual

ships primarily intended for the carriage of solid bulk cargoes

ships specified as a bulk carrier and where many of seagoing loaded conditions in the loading manual are having dry cargoes in bulk

Guidance note: Ships occasionally carrying dry cargo in bulk assigned either ship type notation General dry cargo ship or Multi-purpose dry cargo ship will comply with the provisions of IMO resolution MSC.277(85). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: Ships primarily intended for the carriage of solid bulk cargoes will be defined as a bulk carrier in the SOLAS Cargo Ship Safety Construction Certificate with full SOLAS Ch. XII compliance, except for ships assigned the ship type notation X carrier. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 14

Part 5 Chapter 1 Section 1

Class notation

4.1 Documentation requirements 4.1.1 General dry cargo ship and Multi-purpose dry cargo ship Documentation shall be submitted as required in Table 4. Table 4 Documentation requirements - General dry cargo ship and Multi-purpose dry cargo ship Object

Water ingress 1) alarm system

Documentation type

Additional description

Info

I020– control system functional description

AP

I030 – system block diagram (topology)

AP

I050– power supply arrangement

AP

Z030– arrangement plan

detectors and alarm panel

Z262 – report from test at manufacturer

type test report

Cargo securing arrangements

Z030 – arrangement plan

including position of fixed cargo securing devices, including MSL

FI

Cargo securing devices, fixed

H050 – structural drawing

supporting structure for fixed cargo securing devices

AP

1)

AP AP, TA

only required if intended for occasional carriage of dry cargoes in bulk

AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

4.1.2 Non-CSR Bulk carrier Documentation shall be submitted as required by Table 5. Table 5 Documentation requirements - Non-CSR Bulk carrier Object

Documentation type

Additional description

Info

I020 – control system functional description

AP

I030 – system block diagram (topology)

AP

Water ingress alarm I050 – power supply system arrangement

AP

Z030 – arrangement plan

detectors and alarm panel

Z262 – report from test at manufacturer

type test report

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

AP AP, TA

Page 15

Part 5 Chapter 1 Section 1

4 Documentation

Documentation type

Additional description

Info

AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

4.1.3 CSR Bulk carrier Documentation shall be submitted as required by Table 6 and CSR Pt.1 Ch.1 Sec.3 [2.2]. Table 6 Documentation requirements - CSR Bulk carrier Object

Documentation type

Additional description

Info

I020 – control system functional description

AP

I030 – system block diagram (topology)

AP

Water ingress alarm I050 – power supply system arrangement

AP

Z030 – arrangement plan

detectors and alarm panel

Z262 – report from test at manufacturer

type test report

AP AP, TA

AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

4.1.4 Ore carrier Documentation shall be submitted as required by Table 7. Table 7 Documentation requirements - Ore carrier Object

Documentation type

Additional description

Info

H200 – ship structure access manual

AP

I020 – control system functional description

AP

I030 – system block diagram Water ingress alarm (topology) system I050 – power supply arrangement

AP AP

Z030 – arrangement plan

detectors and alarm panel

Z262 – report from test at manufacturer

type test report

AP AP, TA

AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

4.1.5 X carrier Documentation shall be submitted as required by Table 8.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 16

Part 5 Chapter 1 Section 1

Object

Object

Documentation type

Ship hull structure

Loading and unloading systems

Additional description

Info

H112 – loading sequence description, preliminary

AP, VS

H114 – loading sequence description, final

AP, VS

Z030 – arrangement plan

FI

AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

4.1.6 Great lakes bulk carrier All documentation requirements are covered by main class. 4.1.7 For general requirements for documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.1. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

5 Certification 5.1 Certification requirements 5.1.1 General dry cargo ship and Multi-purpose dry cargo ship Products shall be certified as required by Table 9. Table 9 Certification requirements - General dry cargo ship and Multi-purpose dry cargo ship Object Water ingress alarm system

2)

Cargo securing devices, fixed

Certificate type

Issued by

PC

Society

PC

manufacturer

Certification standard

1)

Additional description

3)

1)

Unless otherwise specified the certification standard is the Society's rules.

2)

Only required if intended for occasional carriage of dry cargoes in bulk.

3)

Upon request product certificate issued by the Society in accordance with DNVGL-CP-0068 will be provided.

PC = product Certificate, MC = material certificate, TR = test report

5.1.2 Non-CSR Bulk carrier Products shall be certified as required by Table 10. Table 10 Certification requirements - Non-CSR Bulk carrier Object Water ingress alarm system 1)

Certificate type

Issued by

PC

Society

Certification standard

1)

Additional description

Unless otherwise specified the certification standard is the Society's rules.

PC = product certificate, MC = material certificate, TR = test report

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 17

Part 5 Chapter 1 Section 1

Table 8 Documentation requirements - X carrier

Table 11 Certification requirements - CSR Bulk carrier Object Water ingress alarm system 1)

Certificate type

Issued by

PC

Society

Certification standard

1)

Additional description

1)

Additional description

Unless otherwise specified the certification standard is the Society's rules.

PC = product certificate, MC = material certificate, TR = test report

5.1.4 Ore carrier Products shall be certified as required by Table 12. Table 12 Certification requirements - Ore carrier Object Water ingress alarm system 1)

Certificate type

Issued by

PC

Society

Certification standard

Unless otherwise specified the certification standard is the Society's rules.

PC = product certificate, MC = material certificate, TR = test report

5.1.5 For general certification requirements, see Pt.1 Ch.3 Sec.4. For a definition of the certification types, Pt.1 Ch.3 Sec.5.

6 Testing 6.1 Testing during newbuilding 6.1.1 Water ingress alarms Requirements for testing water ingress alarms are given in Sec.2 [6.1.4]. 6.1.2 De-watering system for drainage of forward spaces Requirements for testing de-watering system for drainage of forward spaces are given in Sec.2 [6.3.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 18

Part 5 Chapter 1 Section 1

5.1.3 CSR Bulk carrier Products shall be certified as required by Table 11.

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2]. 2

aX, aY, aZ

= longitudinal, transverse and vertical accelerations, in m/s , at xG, yG, zG, as defined in Pt.3 Ch.4 Sec.3 [3.2]

BH

= for holds with vertical inner side connected to inner bottom: B

H

= BIB, as shown in Figure 2

for holds with slanted longitudinal bulkhead connected to inner bottom: B H = breadth of the cargo hold, in m, measured at mid-length of the cargo hold and at the intersection of longitudinal bulkhead and main deck, as shown in Figure 3 for holds with hopper tank and top wing tank: B H =breadth of the cargo hold, in m, measured at mid-length of the cargo hold and at the mid height between the top of hopper tank and the bottom of topside tank, see Figure 4

BIB

= breadth of inner bottom, in m, measured at mid-length of the cargo hold, see Figure 2 to Figure 4

fdc

= dry cargo factor:

hC

= height of bulk cargo, in m, from the inner bottom to the upper surface of bulk cargo, as defined in [3.3.1] or [3.3.2]

hDB

= height, in m, of the double bottom at the centreline, measured at mid-length of the cargo hold, see Figure 2 to Figure 4

hHPL

= for holds with vertical inner side connected to inner bottom:

fdc = 1.0 for strength assessment fdc = 0.5 for fatigue assessment

hHPL = 0 for holds with slanted longitudinal bulkhead connected to inner bottom:

hHPL = hHPU for holds with hopper tank:

hHPL = vertical distance, in m, from the inner bottom at centreline to the upper intersection

of hopper tank and side shell or inner side for double side ships, determined at mid length of the considered cargo hold, as shown in Figure 4

hHPU

= for cargo holds with no top wing tank:

hHPU = vertical distance, in m, from the inner bottom at centreline to the intersection of

longitudinal bulkhead and main deck, determined at mid length of the cargo hold at midship, as shown in Figure 2 and Figure 3 for cargo holds with top wing tank:

hHPU = vertical distance, in m, from the inner bottom at centreline to the lower intersection

of topside tank and side shell or inner side for double side ships, determined at mid length of the cargo hold at midship, as shown in Figure 4

KC

= coefficient: for inner bottom, hopper tank, transverse and longitudinal bulkheads, lower stool, vertical upper stool, inner side and side shell for topside tank, main deck and sloped upper stool

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 19

Part 5 Chapter 1 Section 2

SECTION 2 COMMON REQUIREMENTS

= length of the cargo hold, in m, at the centreline between the transverse bulkheads, see Figure 2 to Figure 4. This shall be measured to the mid-depth of the corrugated bulkhead(s) if fitted

lSF

= side frame span, in m, as defined in Figure 1, shall not be less than 0.25 D

M MFull

= mass, in t, of the bulk cargo being considered = cargo mass, in t, in a cargo hold corresponding to the volume up to the top of the hatch 3 coaming with a density of the greater of MH/VFull or 1.0 t/m

MFull = 1.0 VFull but not less than MH

MH

= cargo mass, in t, in a cargo hold that corresponds to the homogeneously loaded condition at maximum draught with 50% consumables

MHD

= maximum allowable cargo mass, in t, in a cargo hold according to design loading conditions with specified holds empty at maximum draught with 50% consumables

Pbs Pbd VFull

= static internal pressure due to dry bulk cargo, in kN/m , as defined in [3.4.2]

VH

= volume, in m , of cargo hold up to level of the intersection of the main deck with the hatch coaming excluding the volume enclosed by hatch coaming, see Figure 2 to Figure 4

VHC

= volume, in m , of the hatch coaming, from the level of the intersection of the main deck with the hatch side coaming to the top of the hatch coaming, determined for the cargo hold at midship, as shown in Figure 2 to Figure 4

VTS

= total volume, in m , of the portion of the lower bulkhead stools within the cargo hold length lH and inboard of the hopper tanks

x, y, z

=

2

2

= dynamic inertial pressure due to dry bulk cargo, in kN/m , as defined in [3.4.3] 3

= volume, in m , of cargo hold up to top of the hatch coaming:

VFull = VH + VHC 3 3

3

x, y and z coordinates, in m, of the load point with respect to the reference coordinate system defined in Pt.3 Ch.4 Sec.1 [1.2.1]

xG, yG, zG

=

x, y and z coordinates, in m, of the volumetric centre of gravity of the fully filled cargo hold, i.e. VFull, considered with respect to the reference coordinate system defined in Pt.3 Ch.4 Sec.1 [1.2].

In case of partially filled cargo hold, xG, yG, zG shall be:

xG, yG = volumetric centre of gravity of the cargo hold zG = hDB + hC-cl / 2

zC

= height of the upper surface of the cargo above the baseline in way of the load point, in m:

α ψ

= angle, in deg, between panel considered and the horizontal plane

zC = hDB + hC = assumed angle of repose, in deg, of bulk cargo; shall be:

ψ = 30° in general ψ = 35° for iron ore (with ρc = 3.0 t/m3) and for bulk cargoes with ρc ≥ 1.78 t/m3 ψ = 25° for cement ρc

3

= density of bulk cargo, in t/m , as defined in [3.3.3]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 20

Part 5 Chapter 1 Section 2

lH

1.1 Introduction These rules includes common requirements for bulk carriers and dry cargo ships in addition to those that are applicable for the assignment of main character of class.

1.2 Scope This section describes common requirements for dry cargo ships in addition to the requirements described in Pt.3, including: — — — — —

structural design principles, see [2] pressure and forces due to dry bulk cargo, see [3] design load scenarios, see [4] hull local scantling, see [5] water ingress alarms and drainage of forward spaces, see [6].

1.3 Application Unless otherwise specified in the following sub-sections, the requirements given in this section are applicable to bulk carriers and dry cargo ships described in Sec.5 to Sec.9. For ships assigned the ship type notation Bulk carrier (with CSR) only the requirements given in [6.1] and [6.3] are applicable.

2 Structural design principles 2.1 Structural arrangement - double side structure 2.1.1 Primary supporting members Double side web frames shall be fitted in line with primary supporting members in double bottom or in hopper tanks, where fitted, or aligned with large brackets. Where top side tanks are fitted, double side web frames shall be aligned with web frames or large brackets. Transverse primary supporting members shall be fitted in way of hatch end beams or similar large deck opening supporting transverse structure. Horizontal side stringers or scarfing brackets shall be fitted aft of the collision bulkhead in line with fore peak stringers, and forward of engine room bulkhead in line with platform decks in machinery spaces. 2.1.2 Plating connections Inner hull plating and hopper tank structures, where fitted, shall be supported at forward and aft ends, e.g. by scarfing brackets in way of the collision bulkhead and the engine room bulkhead. Connection between the inner hull plating and the inner bottom plating shall be designed such that stress concentration is minimised. Connections of hopper tank plating with inner hull and with inner bottom shall be supported by a longitudinal girder. When a hopper tank is not fitted, the inner hull plating shall be supported by a longitudinal girder below the inner bottom plating and the inner bottom plating shall be supported by scarfing brackets.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 21

Part 5 Chapter 1 Section 2

1 Introduction

2.2.1 Tripping brackets Cargo hold side frames made of angles or bulb profiles having a span lSF > 5 m shall be supported by tripping brackets at the middle of the span. 2.2.2 Side frames in way of hatch end beams in ships without top wing tank In ships without top wing tank, frames at hatch end beams shall be reinforced to withstand the additional bending moment from the deck structure. 2.2.3 Upper and lower bracket The length of the lower bracket, lb in Figure 1, shall not be less than 0.12 lSF. The length of the upper bracket, lb in Figure 1, shall not be less than 0.07 lSF. When the length of the free edge of the bracket is more than 40 times the net plate thickness, a flange shall be fitted. The width being at least 1/15 of the length of the free edge.

Figure 1 Dimensions of side frames - single side skin dry cargo ship

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 22

Part 5 Chapter 1 Section 2

2.2 Structural arrangement - single side structure

2.3.1 Web frame spacing in topside tanks The spacing of web frames in topside tanks shall not be greater than 6 frame spaces. Other arrangements will be considered on a case-by-case basis. 2.3.2 Cross deck between hatches Transverse members supporting the cross deck shall be supported by side or top side tank transverse members. Assessment of the primary supporting members shall be performed applying an advanced calculation method in compliance with the requirements in Pt.3 Ch.6 Sec.6 [2.2]. Smooth connection of the strength deck at side with the cross deck shall be ensured by a plate of intermediate thickness. 2.3.3 Topside tank structures Topside tank structures, where fitted, shall be supported at forward and aft ends, e.g. by scarfing brackets in way of the collision bulkhead and the engine room bulkhead.

2.4 Structural arrangement - plane bulkheads Floors shall be fitted in the double bottom in line with the plane transverse bulkhead.

2.5 Detailed design 2.5.1 Stiffeners For ships intended for the carriage of dry cargoes in bulk the requirements given in Pt.3 Ch.3 Sec.6 [2.4.1] shall be complied with, applying the additional design load sets given in [5.1.3].

3 Pressures and forces due to dry bulk cargo 3.1 Application The pressures and forces due to dry cargo in bulk in a cargo hold shall be determined both for fully and partially filled cargo holds according to [3.4] and [3.5].

3.2 Hold definitions 3.2.1 Geometrical characteristics The main geometrical elements of a box shaped cargo hold are shown in Figure 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 23

Part 5 Chapter 1 Section 2

2.3 Structural arrangement - deck structure

The main geometrical elements of a cargo hold of an ore carrier with slanted longitudinal bulkhead are shown in Figure 3.

Figure 3 Ore carrier with slanted longitudinal bulkhead - definition of cargo hold parameters The main geometrical elements of a cargo hold with hopper tank and top wing tank are shown in Figure 4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 24

Part 5 Chapter 1 Section 2

Figure 2 Box shaped cargo hold - definition of cargo hold parameters

3.2.2 Fully and partially filled cargo holds The definitions of a fully and partially filled dry bulk cargo holds are as follows: a)

Fully filled hold: the dry bulk cargo density is such that the cargo hold is filled up to the top of the hatch coaming, as shown in: — box shaped cargo hold: Figure 5 — ore carrier with slanted longitudinal bulkhead: Figure 6 — cargo hold with hopper tank and top wing tank: Figure 7. The upper surface of the cargo and its effective height in the hold with [3.3.1].

b)

hC shall be determined in accordance

Partially filled hold: the cargo density is such that the cargo hold is not filled up to the top of the hatch coaming, as shown in: — box shaped cargo hold: Figure 8 — ore carrier with slanted longitudinal bulkhead: Figure 9 — cargo hold with hopper tank and top wing tank: Figure 10 or Figure 11. The upper surface of the cargo and its effective height in the hold hC shall be determined in accordance with [3.3.2].

3.3 Dry cargo characteristics 3.3.1 Definition of the upper surface of dry bulk cargo for full cargo holds For a fully filled cargo hold as defined in [3.2.2], including non-prismatic holds, the effective upper surface of the cargo is an equivalent horizontal surface at hC, in m, above inner bottom at centreline as shown in Figure 5 to Figure 7. The value of hC shall be calculated at mid length of the cargo hold at the midship, shall be kept constant over the cargo hold region area, and is determined as follows:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 25

Part 5 Chapter 1 Section 2

Figure 4 Cargo hold with hopper tank and top wing tank - definition of cargo hold parameters

S0

2

= shaded area, in m , shall be: Figure 5: S0 = 0 Figure 6: S0 = shaded area above the intersection of longitudinal bulkhead and main deck and up to the level of the intersection of the main deck with the hatch coaming, determined for the cargo hold at the midship Figure 7: S0 = shaded area above the lower intersection of top side tank and side shell or inner side, as the case may be, and up to the level of the intersection of the main deck with the hatch coaming, determined for the cargo hold at the midship.

Figure 5 Box shaped cargo hold - sefinition of effective upper surface of cargo for a full cargo hold

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 26

Part 5 Chapter 1 Section 2

where:

Figure 7 Cargo hold with hopper tank and top wing tank - efinition of effective upper surface of cargo for a full cargo hold 3.3.2 Definition of the upper surface of dry bulk cargo for partially filled cargo holds For any partially filled cargo hold, as defined in [3.2.2], including non-prismatic holds, the effective upper surface of the cargo shall be made of three parts: — one central horizontal surface of breadth BH/2, in m, at a height hC-CL, in m, above the inner bottom — a sloped surface at each side with an angle ψ/2, in degrees, between the central horizontal surface, and the side shell or inner hull, as shown in Figure 8 to Figure 10, or the hopper plating, as shown in Figure 11, as the case may be.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 27

Part 5 Chapter 1 Section 2

Figure 6 Ore carrier with slanted longitudinal bulkhead - definition of effective upper surface of cargo for a full cargo hold

For

:

For

:

For

:

where:

h1

hC-CL B2

= height, in m, shall be:

— for

h1 ≥ 0 as shown in Figure 8 and Figure 10:

— for

h1 < 0 as shown in Figure 9 and Figure 11

= height, in m, of the cargo surface at the centreline, as shown in Figure 8 to Figure 11 = maximum breadth of the cargo, in m, as shown in Figure 9 and Figure 11.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 28

Part 5 Chapter 1 Section 2

The height of cargo surface hC, in m, shall be calculated at mid length of the considered cargo hold and shall be constant over the length of the hold as follows:

Part 5 Chapter 1 Section 2 Figure 8 Box shaped cargo hold- definition of the effective upper surface of cargo for a partially filled cargo hold

Figure 9 Ore carrier with slanted longitudinal bulkhead - definition of the effective upper surface of cargo for a partially filled cargo hold

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 29

Part 5 Chapter 1 Section 2

Figure 10 Cargo hold with hopper tank and top wing tank - definition of the effective upper surface of cargo for a partially filled cargo hold when h1 ≥ 0

Figure 11 Cargo hold with hopper tank and top wing tank - definition of the effective upper surface of cargo for a partially filled cargo hold when h1 < 0 3.3.3 Mass and density The dry cargo mass and the density of the cargo shall be as follows: — for strength assessment: the values defined in Table 1 — for fatigue assessment: the values defined in Table 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 30

Ship type

In general

Homogeneous loading condition

1)

fully filled hold

partially filled 2) 3) hold

fully filled hold

partially 3) filled hold

M

M = MH

M = MH

M = MHD

M = MHD

ρC but not less than 0.7 M

Ore carrier

Alternate loading condition

Cargo mass Cargo density

M = MH

ρC

4)

maximum value specified in the loading manual M = MH

maximum value specified in the loading manual M = MH

M = MH

ρC = 3.0

ρC = 3.0

1)

Alternate loading conditions are only applicable if such conditions are included in the loading manual.

2)

Homogeneous loading condition with partially filled hold is only applicable if loading conditions having a mass density not less than 1.0 is included in the loading manual.

3)

Loading conditions with partially filled hold are only applicable if filling level heights less than 90% is included in the loading manual.

4)

If a mass density of 0.7 for all cargo holds represents a total cargo intake Σ 0.7 MFull that are exceeding the total cargo capacity of the vessel

ρC may be reduced after special consideration.

Table 2 Dry bulk cargo mass and density for fatigue assessment Ship type

In general

Ore carrier 1)

Homogenous loading condition

Cargo mass Cargo density

fully filled hold

M

M = MH

ρC

Alternate loading condition

N/A

1)

M = MHD N/A

ρC M

partially filled hold

M = MH

ρC = 3.0

maximum value specified in the loading manual

N/A

Alternate loading conditions are only applicable if such conditions are included in the loading manual.

3.3.4 FE application The following process shall be applied for the bulk cargo pressure loads used in FE analysis: a) b) c) d)

determine hc according to [3.3.1] for fully filled cargo hold or [3.3.2] for partially filled cargo hold determine the corresponding static pressure as defined in [3.4.2] and static shear pressure as defined in [3.5.2] using ρc and apply them in the FE model calculate the actual mass of cargo, Mactual, in t 3 determine the effective cargo density, in t/m :

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 31

Part 5 Chapter 1 Section 2

Table 1 Dry bulk cargo mass and density for strength assessment

M Mactual e)

hc in a) = calculated actual cargo mass when applying static pressures and static shear loads in b) = cargo mass being used when determining

calculate the final pressure distribution and shear load using

ρeff

instead of

ρc.

3.4 Dry bulk cargo pressures 3.4.1 Total pressure 2 The total pressure due to dry bulk cargo acting on any load point of a cargo hold boundary, in kN/m , shall be: for strength assessment of intact conditions for static (S) design load scenarios, given in [4] for strength assessment of intact conditions and fatigue assessment for static plus dynamic (S+D) design load scenarios, given in [4] Static and dynamic pressures as defined in [3.4.2] and [3.4.3] for FE analysis shall be determined using instead of

ρc.

ρeff

3.4.2 Static pressure 2 The dry bulk cargo static pressure Pbs, in kN/m , shall be: , but not less than 0. 3.4.3 Dynamic pressure 2 The dry bulk cargo dynamic pressure Pbd, in kN/m , for each load case shall be: for z ≤zc for z > zc

3.5 Shear load 3.5.1 Application For FE strength assessment, the following shear load pressures shall be considered in addition to the dry bulk cargo pressures defined in [3.4] when the load point elevation, z, is lower or equal to zc: — for static (S) design load scenarios, given in [4], static shear load, Pbs-s, due to gravitational forces acting on hopper tanks and lower stools plating, as defined in [3.5.2] — for static plus dynamic (S+D) design load scenarios, given in [4], the following dynamic shear load pressures: Pbs-s + Pbs-d for the hopper tank and the lower stool plating, as defined in [3.5.3] Pbs-dx for the inner bottom plating in the longitudinal direction, as defined in [3.5.4] Pbs-dy for the inner bottom plating in the transverse direction, as defined in [3.5.4]. Shear loads as defined in [3.5.2] to [3.5.4] for FE analysis shall be determined using ρeff instead of ρc.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 32

Part 5 Chapter 1 Section 2

where:

3.5.3 Dynamic shear load on the hopper tank and lower stool plating The dynamic shear load pressure, Pbs-d (positive downward to the plating) due to dry bulk cargo forces on 2 the hopper tank and lower stool plating, in kN/m , for each dynamic load case shall be:

3.5.4 Dynamic shear load along the inner bottom plating The dynamic shear load pressures, Pbs-dx in the longitudinal direction (positive to bow) due to dry bulk cargo 2 forces acting along the inner bottom plating, in kN/m , shall be, for each dynamic load case, as:

The dynamic shear load pressures, Pbs-dy in the transverse direction (positive to port) due to dry bulk cargo 2 forces acting along the inner bottom plating, in kN/m , shall be, for each dynamic load case, as:

4 Design load scenarios 4.1 General The design load scenarios given in Pt.3 Ch.4 Sec.7 shall be complied with, in addition to the additional principal design load scenarios for dry cargo ships given in [4.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 33

Part 5 Chapter 1 Section 2

3.5.2 Static shear load on the hopper tank and lower stool plating The static shear load pressure, Pbs-s (positive downward to the plating) due to dry bulk cargo gravitational 2 forces acting on hopper tank and lower stool plating, in kN/m , shall be:

4.2.1 Additional principal design load scenarios for strength assessment The additional principal design load scenarios for strength assessment of dry cargo ships are given in Table 3. Table 3 Additional principal design load scenarios for strength assessment Design load scenario 6

hull girder 5) loads

Load component

Pex

2)

enhanced flooded requirements

static (S)

static (S)

VBM

Msw-p

Msw-f + 0.8 Mwv

HBM

-

-

VSF

Qsw-p

Qsw-f + 0.8 Qwv

TM

-

-

exposed decks

-

-

external shell

PS

-

superstructure sides

-

-

-

-

boundaries of water ballast tanks

3)

boundaries of tanks other than water ballast tanks Pin

7

FEM assessment of loading/unloading in harbour

superstructure end bulkheads and deckhouse walls

local 6) loads

1)

Pls-3

-

watertight bulkheads

-

boundaries of bulk cargo holds

Pbs

internal structures in tanks

-

-

Pdl

exposed decks and nonexposed decks and platforms

Pdl-s

-

FU

heavy units on internal and external decks

FU-s

-

P

weather deck hatch covers

PC

-

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Pbf-s

4)

Page 34

Part 5 Chapter 1 Section 2

4.2 Additional principal design load scenarios for dry cargo ships

6

2)

FEM assessment of loading/unloading in harbour

enhanced flooded requirements

static (S)

static (S)

1)

Application is further given in [4.2.2].

2)

Application is further given in [4.2.3].

3)

WB cargo hold is considered as ballast tank.

4)

Static pressure Pbf-s shall be applied to vertically corrugated transverse bulkheads only.

5)

Hull girder loads:

6)

7

Msw-f Msw-p

= permissible vertical still water bending moment in flooded condition as defined in Sec.4 [2.1.1]

Qsw-f Qsw-h

= permissible vertical still water shear force in flooded condition as defined in Sec.4 [2.1.1]

= permissible vertical still water bending moment for harbour/sheltered water operation as defined in Pt.3 Ch.4 Sec.4 [2.2.3] = permissible vertical still water shear force for harbour/sheltered water operation as defined in Pt.3 Ch.4 Sec.4 [2.4.3].

Local loads:

PS P ls-3

= hydrostatic sea pressure as given in Pt.3 Ch.4 Sec.5 [1.2]

Pbs Pbf-s

= static dry bulk cargo pressure as given in [3.4.2]

Pdl-s

= static pressure due to distributed load on exposed decks as given in Pt.3 Ch.4 Sec.5 [2.3.1], and static pressure due to distributed load in on non-exposed decks and platforms as given in Pt.3 Ch.4 Sec.6 [2.2.1]

FU-s

= concentrated static force due to unit load on exposed decks as given in Pt.3 Ch.4 Sec.5 [2.3.2], and concentrated static force due to unit load on non-exposed decks as given in Pt.3 Ch.4 Sec.6 [2.3.1]

PC

= uniform cargo load on hatch covers due to cargo loads as given in Pt.3 Ch.12 Sec.4 [2.3.1].

= static tank pressure during normal operations at harbour/sheltered water as given in Pt.3 Ch.4 Sec.6 [1.2.3] = static pressure on vertically corrugated transverse bulkhead of a flooded cargo hold as given in Sec.4 [2.2.6]

4.2.2 FEM assessment of loading/unloading in harbour Design load scenario 6, FEM assessment of loading/unloading in harbour, defined in Table 3 applies to dry cargo ships with minimum one of the following: — ships with harbour/sheltered water loaded loading conditions included in the loading manual — ships where guidance for loading/unloading sequences are required. Guidance note: The application of design load scenario 6 is further defined in tables for standard FE design load combinations given in: —

General dry cargo ship or Multi-purpose dry cargo ship, with a long centre cargo hold: Sec.5 Table 1

—

General dry cargo ship, Multi-purpose dry cargo ship or Bulk carrier (without CSR) assigned the additional notation HC: Pt.6 Ch.1 Sec.4 Table 11 to Pt.6 Ch.1 Sec.4 Table 17.

—

Ore carrier assigned the additional notation OC: Pt.6 Ch.1 Sec.5 Table 7 to Pt.6 Ch.1 Sec.5 Table 12. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 35

Part 5 Chapter 1 Section 2

Design load scenario 1)

The harbour FE design load combinations, applying permissible limits for harbour/sheltered water operation, may be decisive for the structural strength. For ships where the harbour FE design load combinations are governing, the permissible limits for harbour/ sheltered water operation should be established by enveloping the most severe loaded conditions given in the loading manual and/ or loading/unloading sequences. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.2.3 Enhanced flooded requirements Design load scenario 7, Enhanced flooded requirements, defined in Table 3 applies to ships assigned ship type notation Ore carrier or Bulk carrier (without CSR), complying with criteria further given in Sec.4 [1.3]. The application of design load scenario 7 is limited to the following: — transverse vertically corrugated watertight bulkheads separating cargo holds in flooded condition: Sec.4 [3] — allowable hold loading in flooded conditions: Sec.4 [4] — vertical hull girder bending and shear strength in flooded conditions: Sec.4 [5].

5 Hull local scantling 5.1 Design load sets for ships intended to carry dry bulk cargo 5.1.1 Application The design load sets given in [5.1.3] and [5.1.4] apply to the cargo hold region of dry cargo ships, in addition to the design loads sets given in Pt.3 Ch.6 Sec.2, for the following structural members: — additional design load sets for plating and stiffeners, in Table 5 — additional design load sets for primary supporting members, in Table 6. 5.1.2 Load components The static and dynamic load components shall be determined in accordance with the principal design load scenarios given in [4]. Radius of gyration, kr, and metacentric height, GM, shall be in accordance with Table 4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 36

Part 5 Chapter 1 Section 2

Guidance note:

r

and GM values Loading condition

1) 3)

homogeneous loading, fully filled

Full load condition

homogeneous heavy cargo, partially filled

2)

heavy ballast condition

normal ballast condition 1)

k

Ore carrier

0.25B

in general

0.42B

Ore carrier

0.25B T

0.35B SC

GM

r

0.35B

Ore carrier

alternate heavy cargo, partially filled

LC

in general

in general

alternate light cargo, fully filled

steel coil loading

T

Application

0.20B

0.12B

0.25B

0.12B

in general

0.40B

Ore carrier

0.20B

all ships designated for the carriage of steel products

0.42B

0.25B

0.40B

0.25B

0.35B

0.30B

in general Ore carrier in general Ore carrier

T

T

BAL-H

0.45B BAL

0.35B

0.20B

0.33B

For multi-port (MP) loading conditions with draught greater than or equal to 0.9TSC, the values of kr and GM, unless provided in the loading manual, shall be as those from the most appropriate full load condition. For multi-port (MP) loading conditions with draught between TBAL-H and 0.9TSC, the values of kr and GM, unless provided in the loading manual, shall be obtained by linear interpolation, based on the draught, between the heavy ballast condition and the most appropriate full load condition. For multi-port (MP) loading conditions with a draught below TBAL-H, the values of kr and GM for the heavy ballast condition shall be used.

2)

When steel coil loading condition is provided by the designer in the loading manual, this condition shall be assessed with draught, kr and GM values given in this table.

3)

Block loading conditions shall be assessed with draught, kr and GM values given in this table for homogeneous heavy cargo loading condition.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 37

Part 5 Chapter 1 Section 2

Table 4 k

Table 5 Additional design load sets for plating and stiffeners of dry cargo ships Structural member

Boundaries of bulk cargo hold

1)

Design load set

Design load scenario

BC-1

2

BC-2

Load component

Draught

Acceptance criteria

Pbs + Pbd

TSC

AC-II

1

Pbs

-

AC-I

BC-3

2

Pbs + Pbd

TSC

AC-II

BC-4

1

Pbs

-

AC-I

BC-5

2

TSC

AC-II

BC-6

1

-

AC-I

BC-7

2

TSC

AC-II

BC-8

1

-

AC-I

P

bs

P P

bs

P

1)

+ Pbd bs

+ Pbd bs

Loading condition

homogeneous loading, fully filled

homogeneous heavy cargo, partially filled

alternate light cargo, fully filled

alternate heavy cargo, partially filled

Local loads:

Pbs Pbd

= static dry bulk cargo pressure as given in [3.4.2] = dynamic dry bulk cargo pressure as given in [3.4.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 38

Part 5 Chapter 1 Section 2

5.1.3 Additional design load sets for plating and stiffeners of dry cargo ships Additional design load sets for plating and stiffeners of dry cargo ships are given in Table 5.

The severest loading conditions from the loading manual or otherwise specified by the designer shall be considered for the calculation of Pbs + Pbd and Pbs in design load sets BC-11 to BC-14. If loading/unloading sequences are provided the additional design load sets BC-15 and BC-16 applies. Table 6 Additional design load sets for primary supporting members of dry cargo ships Structural member

Boundaries of ballast hold

Boundaries of bulk cargo hold

Design load set

Design load scenario

WB-5

2

WB-6

1

BC-11

2

Load component

Pls-1+Pld – 1) (PS+PW) P P

1)

ls-3

- PS

bs

+ Pbd

- (PS+PW) Pbs-

1

BC-13

2

(PS+PW)

BC-14

1

1)

BC-15

6

Pbs- PS

6

1)

P

S

1)

1)

PS

1)

1) PS

BC-12

BC-16

6)

Acceptance criteria

Draught

TBAL-H

2)

TBAL-H

2)

Loading condition

AC-II

heavy ballast condition

AC-I

TSC

AC-II

TSC

AC-I

TBAL-H/TBAL

3)

AC-II

3) TBAL-H/TBAL

AC-I

TMin

4)

AC-I

TMax

5)

AC-I

full load condition

heavy/normal ballast condition

loading/unloading in harbour

1)

(PS+PW) and PS shall be considered for external shell only

2)

minimum draught among heavy ballast conditions shall be used

3)

maximum draught among all ballast conditions shall be used

4)

minimum draught with hold full according to loading/unloading sequences shall be used

5)

maximum draught with hold empty according to loading/unloading sequences shall be used

6)

local loads:

PS PW

= hydrostatic sea pressure as given in Pt.3 Ch.4 Sec.5 [1.2]

P

ls-1

= static tank pressure during normal operations at sea as given in Pt.3 Ch.4 Sec.6 [1.2.1]

P

ls-3

= static tank pressure during normal operations at harbour/sheltered water as given in Pt.3 Ch.4 Sec.6 [1.2.3]

P

ld

= dynamic tank pressure as given in Pt.3 Ch.4 Sec.6 [1.3]

Pbs Pbd

= wave pressure as given in Pt.3 Ch.4 Sec.5 [1.3]

= static dry bulk cargo pressure as given in [3.4.2] = dynamic dry bulk cargo pressure as given in [3.4.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 39

Part 5 Chapter 1 Section 2

5.1.4 Additional design load sets for primary supporting members of dry cargo ships Additional design load sets for primary supporting members of dry cargo ships are given in Table 6.

5.2.1 Application This sub-section applies to single side structure within the cargo hold region of dry cargo ships with transverse framing. 5.2.2 Net section modulus and net shear sectional area 3 2 The net section modulus Z, in cm , and the net shear sectional area Ashr, in cm , in the mid-span area of side frames subjected to lateral pressure shall not be less than:

where:

αm

= coefficient:

fbdg

= bending coefficient 10

Cs

= permissible bending stress coefficient for the design load set being considered:

αS

αm = 0.42 for side frames of holds that may be empty in alternate conditions αm = 0.36 for other ships

C

s

= 0.75 for acceptance criteria set AC-I

C

s

= 0.90 for acceptance criteria set AC-II

= coefficient:

αS = 1.1 for side frames of holds that may be empty in alternate conditions αS = 1.0 for other side frames

ℓB

= lower bracket length, in m, as defined in Figure 1 without integral bracket and in Figure 12 with integral bracket

P

= design pressures, in kN/m², for design load sets BC-1 to BC-8 as defined in Table 5 and SEA-1 to SEA-2 as defined in Pt.3 Ch.6 Sec.2 Table 1

Ct

= permissible shear stress coefficient for the design load set being considered: C

t

= 0.75 for acceptance criteria set AC-I

C

t

= 0.90 for acceptance criteria set AC-II.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 40

Part 5 Chapter 1 Section 2

5.2 Cargo hold side frames of single side skin construction

Part 5 Chapter 1 Section 2 Figure 12 Side frame integral lower bracket length 5.2.3 Lower bracket of side frame At the level of the lower bracket, as shown in Figure 1 for side frames without integral bracket or in Figure 12 for side frames with integral bracket, the net section modulus of the frame and bracket, or integral bracket, 3 with associated shell plating, shall not be less than twice the required net section modulus Z, in cm , for the frame mid-span area obtained from [5.2.2]. 5.2.4 Upper bracket of side frame At the level of the upper bracket, as shown in Figure 1 for side frames without integral bracket or in Figure 12 for side frames with integral bracket, the net section modulus of the frame and bracket, or integral bracket, with associated shell plating, shall not be less than 1.5 times the net section modulus Z required for the frame mid-span area obtained from [5.2.2]. 5.2.5 Side frames in ballast holds In addition to [5.2.2], for side frames in cargo holds designed to carry ballast water in heavy ballast 3 condition, the net section modulus Z, in cm , and the net web thickness, tw, in mm, all along the span shall be in accordance with Pt.3 Ch.6 Sec.5. The span of the side frame, lf, in m, shall be as defined in Pt.3 Ch.3 Sec.7 [1.1] with consideration of end brackets.

6 Water ingress alarms and drainage of forward spaces 6.1 Water ingress alarms in dry cargo ships carrying dry cargo in bulk 6.1.1 Application This sub-section applies to dry cargo ships with one of the following ship type notations: — General dry cargo ship or Multi-purpose dry cargo ship occasionally carrying dry cargo in bulk — Bulk carrier — Ore carrier

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 41

— In each cargo hold, one when the water level above the inner bottom in any hold reaches a height of 0.5 m and another at a height not less than 15% of the depth of the cargo hold but not more than 2.0 m. — In any ballast tank forward of the collision bulkhead, when the liquid in the tank reaches a level not exceeding 10% of the tank capacity. — In any dry or void space other than a chain cable locker, any part of which extends forward of the foremost cargo hold, at a water level of 0.1 m above the deck. Such alarms are not mandatory in enclosed spaces the volume of which does not exceed 0.1% of the ship's maximum displacement volume. The water ingress detection system shall be type tested in accordance with MSC.188 (79) Performance standards for water level detectors on bulk carriers and single hold cargo ships other than bulk carriers, and be suitable for the cargoes intended. Guidance note: The appendix to the classification certificate will contain information as to which cargoes the systems are approved for. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.1.3 Installation The sensors shall be located in a protected position that is in communication with the after part of the cargo hold or tank and or space, such that the position of the sensor detects the level that is representative of the levels in the actual hold space or tank. These sensors shall be located: — either as close to the centre line as practicable, or — at both the port and starboard sides. The detector installation shall not inhibit the use of any sounding pipe or other water level gauging device for cargo holds or other spaces. Detectors and equipment shall be installed where they are accessible for survey, maintenance and repair. Any filter element fitted to detectors shall be capable of being cleaned before loading. Electrical cables and any associated equipment installed in cargo holds shall be protected from damage by cargoes or mechanical handling equipment associated with cargo handling operations, such as in tubes of robust construction or in similar protected locations. The part of the electrical system which has circuitry in the cargo area shall be arranged intrinsically safe. The power supply shall be in accordance with Pt.4 Ch.9 Sec.3 [2.2]. 6.1.4 Testing After installation the system is subject to testing consisting of: — — — — —

inspection of the installation demonstration of facilities for filter cleaning demonstration of facilities for testing of the detector test of all alarm loops test of the alarm panel functions.

6.2 Water ingress alarms in single hold cargo ships 6.2.1 Application This sub-section applies to single hold cargo ships that shall comply with SOLAS. 6.2.2 Performance requirements Single hold cargo ships shall be fitted with water level detectors giving audible and visual alarms on the navigation bridge when the water level above the inner bottom in the cargo hold reaches a height of not less

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 42

Part 5 Chapter 1 Section 2

6.1.2 Performance requirements The ship shall be fitted with water level detectors giving audible and visual alarms on the navigation bridge:

The water ingress detector equipment shall be type tested in accordance with MSC.188 (79) Performance standards for water level detectors on bulk carriers and single hold cargo ships other than bulk carriers, and be suitable for the cargoes intended. Guidance note: The appendix to the classification certificate will contain information as to which cargoes the systems are approved for. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.2.3 Installation Installation shall be carried out in accordance with [6.1.3]. 6.2.4 Testing Testing shall be carried out in accordance with [6.1.4].

6.3 Availability of pumping systems 6.3.1 Application This sub-section applies to dry cargo ships with one of the following ship type notations: — General dry cargo ship or Multi-purpose dry cargo ship occasionally carrying dry cargo in bulk — Bulk carrier — Ore carrier . 6.3.2 Availability of drainage for forward spaces The means for draining and pumping ballast tanks forward of the collision bulkhead, and bilges of dry spaces, any part of which extends forward of the foremost cargo hold, shall be capable of being brought into operation from a readily accessible enclosed space. The location shall be accessible from the navigation bridge or propulsion machinery control position, without need for traversing exposed freeboard or superstructure decks. This does not apply to the enclosed spaces the volume of which does not exceed 0.1% of the ship's maximum displacement volume. Nor does it apply to the chain cable lockers. Guidance note: Where pipes serving such tanks or bilges pierce the collision bulkhead, as an alternative to the valve control specified in Pt.4 Ch.6 Sec.3 [1.4.2], valve operation by means of remotely operated actuators may be accepted, provided that the location of such valve controls complies with this regulation. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

The dewatering system for ballast tanks forward of the collision bulkhead and for bilges of dry spaces, any part of which extends forward of the foremost cargo hold, shall be designed to remove water from the 3 2 forward spaces at a rate of not less than 320A m /h, where A is the cross-sectional area in m of the largest air pipe or ventilator pipe connected from the exposed deck to a closed forward space that is required to be dewatered by these arrangements. 6.3.3 Testing and installation The installation and testing on board shall be in accordance with Pt.4 Ch.6 Sec.4 for bilge systems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 43

Part 5 Chapter 1 Section 2

than 0.3 m and another level when such level reaches not more than 15% of the mean depth of the cargo hold.

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2].

aX, aY, aZ

= longitudinal, transverse and vertical accelerations, in m/s2, at xG, yG, zG, as defined in Pt.3 Ch.4 Sec.3 [3.2]

dsc dshr Fsc-ib-s Fsc-ib Fsc-hs-s Fsc-hs hDB

= diameter, in m, of a steel coil

hHPL

= vertical distance, in m, from the inner bottom at centreline to the upper intersection of hopper tank and side shell or inner side for double side bulk carriers, determined at mid length of the considered cargo hold, as shown in Sec.2 [3.2.1]

ℓ ℓlp

= effective shear depth of the stiffener as defined in Pt.3 Ch.3 Sec.7 [1.4.3] = static load on inner bottom, in kN, as defined in [2.3.1] = total load on inner bottom, in kN, as defined in [2.2.1] = static load on hopper/inner side, in kN, as defined in [2.3.2] = total load on hopper/inner side, in kN, as defined in [2.2.2] = height, in m, of the double bottom at the centreline, measured at mid-length of the cargo hold, see Sec.2 [3.2.1]

hHPL = 0 if there is no hopper tank = distance, in m, between floors = distance, in m, between outermost dunnage per elementary plate panel (EPP) in the ship x direction, see Figure 3

ℓst Msc-ib Msc-hs n1 n2 n3 R Tθ VFull

= length, in m, of a steel coil

W x, y, z

= mass, in t, of a steel coil

φ θ

= pitch angle, in deg, defined in Pt.3 Ch.4 Sec.3 [2.1.2]

θh

= angle, in deg, between inner bottom plate and hopper sloping plate. In general θh is such that:

= equivalent mass of a steel coil, in t, on inner bottom, as defined in [2.3.1] = equivalent mass of a steel coil, in t, on hopper side, as defined in [2.3.2] = number of tiers of steel coils = number of load points per EPP of the inner bottom, see [2.1.2] = number of dunnages supporting one row of steel coils = vertical coordinate, in m, of the ship rotation centre, defined in Pt.3 Ch.4 Sec.3 = roll period, in s, as defined in Pt.3 Ch.4 Sec.3 [2.1.1] 3

= volume, in m , of cargo hold up to top of the hatch coaming:

VFull = VH + VHC = x, y and y coordinates, in m, of the load point with respect to the reference coordinate system defined in Pt.3 Ch.4 Sec.1 [1.2.1] = roll angle, in deg, defined in Pt.3 Ch.4 Sec.3 [2.1.1]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 44

Part 5 Chapter 1 Section 3

SECTION 3 STEEL COIL REQUIREMENTS

1.1 Introduction Ships may be loaded with steel coils on wooden dunnage. Such loading needs special consideration with additional strength requirements that are outlined in this section.

1.2 Scope This section describes requirements for steel coil loading, including: — steel coil loads in cargo holds, see [2] — hull local scantling, see [3].

1.3 Application The rules in this section apply to all ships loaded with steel coils on wooden dunnage. Ships assigned the ship type notation Bulk carrier (with CSR) are exempted from these requirements.

2 Steel coil loads in cargo holds 2.1 General 2.1.1 Application In Figure 1 typical loading of steel coils on wooden dunnage can be seen. It is assumed that all the steel coils have the same characteristics. In cases where steel coils are lined up in two or more tiers, formulae in [2.1.2] and [2.2] can be applied assuming that only the lowest tier of steel coils is in contact with hopper sloping plate or inner side plate. In other cases, scantling requirements shall be determined on a case-by-case basis.

Figure 1 Inner bottom loaded by steel coils The two following arrangements of steel coils on the inner bottom are considered: — the steel coils are positioned without respect to the location of the floors, as shown in Figure 2 — the steel coils are positioned with respect to the location of the floors, as shown in Figure 3.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 45

Part 5 Chapter 1 Section 3

1 Introduction

Part 5 Chapter 1 Section 3

2.1.2 Arrangement of steel coils independently of the floor locations For steel coils loaded without respect to the location of floors, see Figure 2: — the number n2 of load point dunnages per EPP shall be found in Table 1 — the distance ℓlp, in m, between outermost load point dunnages per EPP shall be found in Table 2. Table 1 Number n2 of load point dunnages per EPP as a function of n3 n

n 2

2

3

3

4

5

1

2

3

4

5

6

7

8

9

10

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 46

n

n 2

2

1

ℓlp, in m

Part 5 Chapter 1 Section 3

Table 2 Distance between outermost load point dunnages per EPP, 3

3

4

5

actual breadth of dunnages

2

0.5ℓst

0.33ℓst

0.25ℓst

0.2ℓst

3

1.2ℓst

0.67ℓst

0.50ℓst

0.4ℓst

4

1.7ℓst

1.20ℓst

0.75ℓst

0.6ℓst

5

2.4ℓst

1.53ℓst

1.20ℓst

0.8ℓst

6

2.9ℓst

1.87ℓst

1.45ℓst

1.2ℓst

7

3.6ℓst

2.40ℓst

1.70ℓst

1.4ℓst

8

4.1ℓst

2.73ℓst

1.95ℓst

1.6ℓst

9

4.8ℓst

3.07ℓst

2.40ℓst

1.8ℓst

10

5.3ℓst

3.60ℓst

2.65ℓst

2.0ℓst

n2 and

Figure 2 Steel coils loaded independently of floors locations 2.1.3 Arrangement of steel coils between floors For steel coils loaded with respect to the locations of floors, see Figure 3: — the number n2 of load point dunnages per EPP shall be: n2 = n3 — the distance ℓlp between outermost load point dunnages per EPP shall be equal to the distance between the outermost dunnage supporting one row of steel coils.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 47

2.1.4 Centre of gravity of steel coil cargo The position of the centre of gravity of the steel coil cargo of the considered cargo hold shall be calculated as follows: a)

longitudinal position

b)

xGsc is the x coordinate, in m, of the volumetric centre of gravity of the considered cargo hold with respect to the reference coordinate system defined in Pt.3 Ch.4 Sec.1 [1.2.1]. transverse position

c)

vertical position

where:

ε

= coefficient shall be:

ε = 1.0 when a port side structural member is assessed ε = -1.0 when a starboard side structural member is assessed.

2.2 Total loads 2.2.1 Total load on the inner bottom The total load Fsc-ib, in kN, due to steel coil cargoes on the inner bottom shall be: but not less than 0 where:

Fsc-ib-s Fsc-ib-d CXG, CYG

= static load, in kN, on the inner bottom, given in [2.3.1] = dynamic load, in kN, on the inner bottom, given in [2.4.2] = load combination factors, as defined in Pt.3 Ch.4 Sec.2 [2.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 48

Part 5 Chapter 1 Section 3

Figure 3 Steel coils loaded between floors

Part 5 Chapter 1 Section 3

2.2.2 Total load on the hopper/inner side The total load Fsc-hs, in kN, due to steel coil cargoes on the hopper/inner side shall be: but not less than 0 where:

Fsc-hs-s Fsc-hs-d CXG, CYG

= static load, in kN, on the hopper/inner side, given in [2.3.2] = dynamic load, in kN, on the hopper/inner side, given in [2.4.3] = load combination factors, as defined in Pt.3 Ch.4 Sec.2 [2.2].

2.3 Static loads 2.3.1 Static loads on the inner bottom The static load Fsc-ib-s, in kN, on the inner bottom due to steel coils shall be:

where:

Msc-ib

KS

= equivalent mass of steel coils, in t, shall be: for

and

for

or

= coefficient shall be: K

S

= 1.4 when steel coils are stowed in one tier with a key coil

K

S

= 1.0 in other cases.

2.3.2 Static load on the hopper/inner side The static load Fsc-hs-s, in kN, on the hopper/inner side due to steel coils shall be:

where:

Msc-hs

Ck

= equivalent mass of steel coils, in t, shall be: for

and

for

or

= coefficient shall be: C k = 3.2 when steel coils are stowed in two or more tiers, or when steel coils are stowed in one tier and a key coil is located 2nd or 3rd from hopper sloping plate or inner hull plate C

k

= 2.0 for other cases.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 49

2.4.1 Tangential roll acceleration 2 The tangential roll acceleration aR, in m/s , shall be:

where:

yGsc

=

zGsc

=

y coordinate, in m, of the centre of gravity of the steel coil cargo of the considered cargo hold, given in [2.1.4]

z coordinate, in m, of the centre of gravity of the steel coil cargo of the considered cargo hold, given in [2.1.4].

2.4.2 Dynamic load on the inner bottom The dynamic load Fsc-ib-d, in kN, on the inner bottom due to steel coils shall be:

where:

az

2

= vertical acceleration, in m/s , as defined in Pt.3 Ch.4 Sec.3 [3.2.3], calculated at the centre of gravity of the steel coil cargo of the considered cargo hold, given in [2.1.4].

2.4.3 Dynamic load on the hopper/inner side The dynamic load Fsc-hs-d, in kN, on the hopper/inner side due to steel coils shall be:

where:

ε CYS, CYR asway aR yGsc

= coefficient defined in [2.1.4]

zGsc

=

= load combination factors, defined in Pt.3 Ch.4 Sec.2 [2.2] 2

= sway acceleration, in m/s , as defined in Pt.3 Ch.4 Sec.3 [2.2.2] 2

= tangential acceleration, in m/s , as defined in [2.4.1] =

y coordinate, in m, of the centre of gravity of the steel coil cargo of the considered cargo hold, given in [2.1.4]

z coordinate, in m, of the centre of gravity of the steel coil cargo of the considered cargo hold, given in [2.1.4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 50

Part 5 Chapter 1 Section 3

2.4 Dynamic loads

3.1 General 3.1.1 The net thickness of inner bottom plating, hopper side plating and inner hull plating for ships intended to carry steel coils shall comply with [3.3.1] and [3.4.1] up to a height not less than the one corresponding to the top of upper tier in touch with hopper or inner hull plating. The net section modulus and the net shear sectional area of longitudinal stiffeners on inner bottom, hopper tank top and inner hull for ships intended to carry steel coils shall comply with [3.3.2] and [3.4.2] up to a height not less than the one corresponding to the top of upper tier in touch with hopper or inner hull plating.

3.2 Load application 3.2.1 Design load sets The static and dynamic load components shall be determined in accordance with the principal design load scenarios given in Sec.2 [4]. Radius of gyration, kr, and metacentric height, GM, shall be in accordance with Sec.2 [5.1.2] for the considered loading condition specified in the design load set. The design load sets for steel coil loading is given in Table 3. Table 3 Design load sets

Structural member

Design load set

Design load scenario

Load component

inner bottom, hopper sloping plate and inner hull

BC-9

1

Fsc-ib-s or Fsc-hs-s

T

inner bottom, hopper sloping plate and inner hull

BC-10

2

Fsc-ib or Fsc-hs

T

Acceptance criteria

Loading condition for definition of GM and kr

SC

AC-I

steel coil condition

SC

AC-II

steel coil condition

Draught

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 51

Part 5 Chapter 1 Section 3

3 Hull local scantling

Part 5 Chapter 1 Section 3

3.3 Inner bottom 3.3.1 Inner bottom plating The net thickness t, in mm, of plating of longitudinally stiffened inner bottom shall not be less than:

for design load set BC-9

for design load set BC-10

where:

K1

= coefficient:

K2

= coefficient:

Ca

= permissible bending stress coefficient, as defined in Pt.3 Ch.6 Sec.4 [1.1.1].

3.3.2 Stiffeners of inner bottom plating

The net section modulus Z, in cm , and the net web thickness, tw, in mm, of stiffeners located on inner bottom plating shall not be less than: 3

and

for design load set BC-9

and

for design load set BC-10

where:

K3

= coefficient as defined in Table 4

Cs Ct

= permissible bending stress coefficient, as defined in Pt.3 Ch.6 Sec.5 [1.1.2]

n2

= number of load points per EPP of the inner bottom, see [2.1].

K3 = 2ℓbdg/3, when n2 > 10 = permissible shear stress coefficient for the design load set being considered, shall be:

Ct = 0.85 for acceptance criteria set AC-I Ct = 1.00 for acceptance criteria set AC-II

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 52

n

K3

2

1

2

3

4

5

6

7

8

9

10

K3 n

2

K3

3.4 Hopper tank and inner hull 3.4.1 Hopper side plating and inner hull plating The net thickness t, in mm, of plating of longitudinally stiffened bilge hopper sloping plate and inner hull shall not be less than: for design load set BC-9

for design load set BC-10 where:

K1 Ca

= coefficient as defined in [3.3.1] = as defined in [3.3.1].

3.4.2 Stiffeners of hopper side plating and inner hull plating

The net section modulus Z, in cm , and the net web thickness, tw, in mm, of stiffeners located on bilge hopper sloping plate and inner hull plate shall not be less than: 3

and

for design load set BC-9

and

for design load set BC-10

where:

K3

= coefficient as defined in Table 4

Cs, Ct

= as defined in [3.3.2].

K 3 = 2ℓbdg/3 when n2 > 10

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 53

Part 5 Chapter 1 Section 3

Table 4 Coefficient

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2].

D1

= distance, in m, from the baseline to the freeboard deck at side amidships

FR

= resultant force, in kN, as defined in Table 5

hC

= height of bulk cargo, in m, from the inner bottom to the upper surface of bulk cargo, as defined in Sec.2 [3.3.1] or Sec.2 [3.3.2]

hDB

= height, in m, of the double bottom at the centreline, measured at mid-length of the cargo hold, see Sec.2 [3.2.1]

hLS

= mean height, in m, of the lower stool, measured from the inner bottom

KC-f

= coefficient:

M

= mass, in t, of the bulk cargo being considered

MFull

= cargo mass, in t, in a cargo hold corresponding to the volume up to the top of the hatch 3 coaming with a density of the greater of MH/VFull or 1.0 t/m and MFull = 1.0 VFull but not less than MH

MH

= cargo mass, in t, in a cargo hold that corresponds to the homogeneously loaded condition at maximum draught with 50% consumables

MHD

= maximum allowable cargo mass, in t, in a cargo hold according to design loading conditions with specified holds empty at maximum draught with 50% consumables

Msw-f

= permissible vertical still water bending moment in flooded condition, in kNm, at the hull transverse section being considered in hogging and sagging, as defined in [2.1.1]

Mwv

= vertical wave bending moment in seagoing condition, in kNm, at the hull transverse section being considered in hogging and sagging, as defined in Pt.3 Ch.4 Sec.4 [3.1]

perm

= permeability of cargo, shall be: perm = 0.3 for iron ore, coal cargoes and cement perm = 0 for steel coils 2

PR

= resultant pressure, in kN/m , as defined in Table 5

Qsw-f

= positive and negative permissible vertical still water shear force in flooded condition, in kN, at the hull transverse section being considered, as defined in [2.1.1]

Qwv

= positive and negative vertical wave shear force in seagoing condition, in kN, at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [3.2]

Qsw-Lcd-f

= vertical still water shear force in flooded condition, in kN, at the hull transverse section being considered, for a seagoing loading condition defined in the loading manual being flooded according to [2.1.2]

sC

= half pitch, in mm, of the corrugation flange as defined in Pt.3 Ch.3 Sec.6 Figure 11

VFull

= volume, in m , of cargo hold up to top of the hatch coaming:

VH

= volume, in m , of cargo hold up to level of the intersection of the main deck with the hatch coaming excluding the volume enclosed by hatch coaming, see Sec.2 [3.2.1]

3

VFull = VH +VHC 3

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 54

Part 5 Chapter 1 Section 4

SECTION 4 ENHANCED FLOODED REQUIREMENTS

= volume, in m , of the hatch coaming, from the level of the intersection of the main deck with the hatch side coaming to the top of the hatch coaming, determined for the cargo hold at midship, as shown in Sec.2 [3.2.1]

x, y, z

= x, y and z coordinates, in m, of the load point with respect to the reference coordinate system defined in Pt.3 Ch.4 Sec.1 [1.2.1]

zC

= height of the upper surface of the cargo above the baseline in way of the load point, in m, shall be: z

C

= hDB + hC 3

ZB-gr

= gross section modulus, in m , at bottom, shall be calculated according Pt.3 Ch.5 Sec.2 [1.2.1]

ZD-gr

= gross section modulus, in m , at deck, shall be calculated according Pt.3 Ch.5 Sec.2 [1.2.2]

ψ

= assumed angle of repose, in deg, of bulk cargo - shall be:

3

ψ = 30° in general ψ = 35° for iron ore (with ρc = 3.0 t/m3) and for bulk cargoes with ρc ≥ 1.78 t/m3 ψ = 25° for cement ρc

3

= density of bulk cargo, in t/m , as defined in [2.2.5].

1 Introduction 1.1 Introduction These rules provide enhanced flooded requirements for ships intended for carriage of heavy dry bulk cargo.

1.2 Scope This section describes enhanced flooded requirements for dry cargo ships in addition to the requirements described in Pt.3, including: — — — —

hull girder loads, pressures and forces due to dry cargoes in flooded conditions, see [2] transverse vertically corrugated watertight bulkheads in flooded condition, see [3] allowable hold loading in flooded conditions, see [4] hull girder strength in flooded conditions, see [5].

1.3 Application This section applies to: — Ships assigned the ship type notation Ore carrier, with OC(H) or OC(M) notation, if any part of longitudinal bulkhead in any cargo hold is located within B/5 or 11.5 m, whichever is less, inboard from the ship’s side at right angle to the centreline at the assigned summer load line. Only cargo holds in way of the double side-skin space which do not meet the criteria given above shall be considered flooded. — Ships assigned the ship type notation Bulk carrier (without CSR), with HC(A), HC(B) or HC(B*) notation. — Ships assigned the ship type notation Bulk carrier (without CSR), with HC(M) notation, if the ship is 3 carrying solid bulk cargo having a density of 1.0 t/m and above.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 55

Part 5 Chapter 1 Section 4

3

VHC

2.1 Vertical still water hull girder loads 2.1.1 Flooded conditions The designer shall provide the envelope of permissible still water bending moment and shear force in flooded condition. Each cargo hold shall be considered individually flooded to the equilibrium waterline. The permissible vertical still water bending moment and shear force in flooded condition at sea at any longitudinal position shall envelope the most severe flooded seagoing loading conditions defined in the loading manual, i.e. all seagoing loaded and ballast conditions. Flooding check of harbour conditions, docking condition afloat, loading/unloading sequences and ballast water exchange are not applicable. 2.1.2 Flooding criteria To calculate the mass of water ingress, the following assumptions shall be made: — the permeability of empty cargo spaces and volume left in loaded cargo spaces above any cargo shall be 0.95 — appropriate values of permeability and bulk density shall be used for any cargo carried. For iron ore, a 3 minimum permeability of 0.3 with a corresponding bulk density of 3.0 t/m shall be used. For cement, a 3 minimum permeability of 0.3 with a corresponding bulk density of 1.3 t/m shall be used. In this respect, permeability for solid bulk cargo means the ratio of the floodable volume between the particles, granules or any larger pieces of the cargo, to the gross volume of the bulk cargo. For packed cargo conditions (such as steel mill products), the actual density of the cargo shall be used with a permeability of zero.

2.2 Vertically corrugated transverse watertight bulkheads 2.2.1 Application The pressure defined in this sub-section applies to vertically corrugated transverse watertight bulkheads of the cargo holds of dry cargo ships for the assessment in flooded conditions. Each cargo hold shall be considered individually flooded, see Figure 1, Figure 2 and Figure 3. 2.2.2 General The loads to be considered as acting on each bulkhead are those given by the combination of loads induced by cargo loads with those induced by the flooded loads of one hold adjacent to the bulkhead under examination. In any case, the pressure due to the flooded loads without cargo shall also be considered. The most severe combinations of cargo induced loads and flooded loads shall be used for the check of the scantlings of each bulkhead, depending on the loading conditions included in the loading manual considering the individual flooded condition of both loaded and empty holds: — homogeneous loading conditions — non-homogeneous loading conditions. For the purpose of this section, the following items are defined as: — design load limits: the specified design load limits for the cargo holds shall be represented by loading conditions defined by the designer in the loading manual

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 56

Part 5 Chapter 1 Section 4

2 Hull girder loads, pressures and forces due to dry cargoes in flooded conditions

unless the ship is intended to carry, in non-homogeneous conditions, only iron ore or cargo having bulk 3 density equal to or greater than 1.78 t/m , the maximum mass of cargo which may be carried in the hold shall also be considered to fill that hold up to the top of the hatch coaming — homogeneous loading conditions: homogeneous loading condition means a loading condition in which the ratio between the highest and the lowest filling level, evaluated for each hold, does not exceed 1.20; it shall be corrected for different cargo densities — packed cargoes: holds carrying packed cargoes (such as steel mill products) shall be considered as empty — unconsidered loading conditions: non-homogeneous part loading conditions associated with multi-port loading and unloading operations for homogeneous loading conditions are not mandatory for the verification of these requirements. 2.2.3 Flooded level The flooded level zF is the distance, in m, measured vertically from the baseline with the ship in the upright position, and obtained from Table 1. Table 1 Flooded level zF, in m, for vertically corrugated transverse bulkheads Vertically corrugated transverse bulkhead position

Ship type dry cargo ships with less than 50,000 t deadweight with Type B freeboard

others

zF = 0.95 D1

zF = 0.85 D1

zF = 0.9

1) D1

zF = D 1

other dry cargo ships 1)

foremost

zF = 0.95

1) D1

1)

zF = 0.8 D1

zF = 0.9 D1 1)

zF = 0.85 D1

3

For ships carrying cargoes having bulk density less than 1.78 t/m in non-homogeneous loading conditions.

2.2.4 Flooded patterns Three different flooded patterns shall be considered: — the flooded level is below the upper surface of the cargo, (see Figure 1: zC > zF) — the flooded level is above the upper surface of the cargo, (see Figure 2: zC ≤ zF) — the flooded hold is empty, (see Figure 3: zC = hDB).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 57

Part 5 Chapter 1 Section 4

— maximum cargo mass to consider:

Part 5 Chapter 1 Section 4

Figure 1 Flooded level below upper surface of bulk cargo

Figure 2 Flooded level above upper surface of bulk cargo

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 58

Part 5 Chapter 1 Section 4

Figure 3 Flooded cargo hold without cargo 2.2.5 Mass and density in flooded condition The dry cargo mass and the density of the cargo shall be as defined in Table 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 59

Ship type

Cargo mass Cargo density M

HC(B)

ρ

ρ

ρ

M = MH

M = MH ρ

M = MH

M = MH

C

M OC(H)

ρ

OC(M)

ρ

M = MH

C

C

= 3.0

= 3.0

M = MH

partially filled hold

fully filled hold

hold loaded with 2) ρC ≤ 1.78 t/m

N/A

1)

M = MHD 1)

M = MHD ρ

M = 1.2 MFull 1)

M = MH

= 3.0

C

M = MHD 1)

M = 1.2 MFull ρ

M = MHD

= 3.0

C

1)

ρ

= 1.78

M = 1.2 MFull ρ

M = MHD maximum value specified in the loading manual

C

C

= 1.78

M = MHD

ρ

C

= 1.78

M = MH ρ

C

M

C

Alternate loading condition

maximum value specified in the loading manual

3)

ρ

= 3.0

M = MH ρ

M = MH

C

M = MH ρ

C

M HC(M)

partially filled hold

C

M HC(B*)

fully filled hold

C

M HC(A)

Homogeneous loading condition

C

M = MH ρ

C

N/A

= 3.0 M = MH

= 3.0

M = MH ρ

C

= 3.0

N/A

1)

shall be 3.0 unless an alternative maximum allowable cargo density is specified in the loading manual. In such cases, the maximum density of the cargo that the ship is allowed to carry shall be indicated within the additional notation Maximum cargo density (x.y t/m3) as defined in Pt.1 Ch.2.

2)

shall be applied for bulk carriers that are required to carry cargoes with a density less than or equal to 1.78 t/m

3)

Alternate loading conditions are only applicable if such conditions are included in the loading manual.

3

2.2.6 Pressures and forces on vertically corrugated transverse bulkheads of flooded cargo holds 2 The static pressure Pbf-s, in kN/m , at any point of the vertically corrugated transverse bulkhead located at a level z from the baseline is given in Table 3 for each flooded pattern defined in [2.2.4]. The force Fbf-s, in kN, acting on a corrugation of a transverse bulkhead is given by Table 4 for each flooded pattern defined in [2.2.4], where:

Pbf-s-LE

= static pressure calculated according to Table 1 for z = hLS + hDB.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 60

Part 5 Chapter 1 Section 4

Table 2 Dry bulk cargo mass and density for strength assessment in flooded condition

Flooded case

Load calculation point

Pressure Pbf-s, in kN/m

2

z > zC zC ≥ z ≥ zF zF > z ≥ hDB z > zF zF ≥ z ≥ zC

Pbf-s = ρg (zF – z)

zC > z ≥ hDB

Table 4 Force acting on a corrugation in the flooded cargo holds Fbf-s Flooded case z

C

> zF

z

F

≥ zC

Force Fbf-s, in kN

2.2.7 Pressures and forces on vertically corrugated transverse bulkheads of non-flooded cargo holds 2 The static pressure Pbs, in kN/m , at a point of the vertically corrugated transverse bulkhead, located at the level z from the baseline, due to dry bulk cargo in a non-flooded cargo hold transverse bulkhead, which is flooded on the other side, shall be: but not less than 0. The resultant force Fbs, in kN, acting on a corrugation shall be:

2.2.8 Resultant pressures and forces on vertically corrugated transverse bulkheads of flooded cargo holds 2 The resultant pressure PR, in kN/m , at each point of the bulkhead, and the resultant force FR, in kN, acting on a corrugation, given in Table 5, shall be considered for the assessment in flooded conditions of vertically corrugated transverse bulkhead structures, where:

Pbf-s = pressure in the flooded cargo holds, in kN/m2, as defined in [2.2.6] Pbs = pressure in the non-flooded cargo holds, in kN/m2, as defined in [2.2.7] Fbf-s = force acting on a corrugation in the flooded cargo holds, in kN, as defined in [2.2.6]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 61

Part 5 Chapter 1 Section 4

Table 3 Static pressure on vertically corrugated transverse bulkhead of a flooded cargo hold Pbf-s

= force acting on a corrugation in the non-flooded cargo holds, in kN, as defined in [2.2.7].

Table 5 Resultant pressure PR and resultant force FR on vertically corrugated transverse bulkhead in flooded condition 2

Loading condition

Resultant pressure PR, in kN/m

Resultant force FR, in kN

homogeneous

PR = Pbf-s – 0.8 Pbs

FR = Fbf-s – 0.8 Fbs

alternate

PR = Pbf-s

FR = Fbf-s

Application in general

2)

HC(A), HC(B*), 1) HC(M) and OC(M)

1)

Alternate loading conditions are only applicable if such conditions are included in the loading manual.

2)

Loading conditions in which the ratio between hc, evaluated for each hold, does not exceed 1.2.

2.3 Double bottom in cargo hold region in flooded conditions 2.3.1 General The loads to be considered as acting on the double bottom are those given by the external sea pressures and the combination of the cargo loads with those induced by the flooding of the hold to which the double bottom belongs. The most severe combinations of cargo induced loads and flooded loads shall be used, depending on the loading conditions included in the loading manual: — homogeneous loading conditions — non-homogeneous loading conditions — packed cargo conditions (such as in the case of steel mill products). For each loading condition, the maximum allowable dry bulk cargo density shall be determined in calculating the allowable hold loading. 2.3.2 Flooded level The flooded level zF is the distance, in m, measured vertically from the baseline with the ship in the upright position, and obtained from Table 6. Table 6 Flooded level zF, for double bottom in cargo hold region Cargo hold

Ship type

foremost

dry cargo ships with less than 50,000 t deadweight with type B freeboard

z

F

z

other dry cargo ships

= 0.95 D1 F

= D1

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

others z z

F F

= 0.85 D1 = 0.9 D1

Page 62

Part 5 Chapter 1 Section 4

Fbs

3.1 Structural arrangement 3.1.1 General For ships of 190 m of length L and above, the transverse vertically corrugated watertight bulkheads shall be fitted with a lower stool, and generally with an upper stool below deck. For ships having length L less than 190 m, corrugations may extend from inner bottom to deck. 3.1.2 Lower stool The lower stool, when fitted, shall have a height in general not less than 3 corrugation depths. The ends of stool side ordinary stiffeners, when fitted in a vertical plane, shall be attached to brackets at the upper and lower ends of the stool. Lower stool side vertical stiffeners and their brackets in the stool shall be aligned with the inner bottom structures such as longitudinals or similar. Lower stool side plating shall not be knuckled anywhere between the inner bottom plating and the stool top plate. The distance d from the edge of the stool top plate to the surface of the corrugation flange shall be in accordance with Figure 4. The lower stool shall be installed in line with double bottom floors or girders as the case may be, and shall have a width not less than 2.5 corrugation depths. The stool shall be fitted with diaphragms in line with the longitudinal double bottom girders or floors. Scallops in the brackets and diaphragms in way of the connections to the stool top plate shall be avoided. The stool side plating shall be connected to the stool top plate and the inner bottom plating by either full penetration or partial penetration welds. The supporting floors shall be connected to the inner bottom by either full penetration or partial penetration welds.

Figure 4 Permitted distance, d, from the edge of the stool top plate to the surface of the corrugation flange

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 63

Part 5 Chapter 1 Section 4

3 Transverse vertically corrugated watertight bulkheads separating cargo holds in flooded condition

Rectangular stools shall have a height in general equal to twice the depth of corrugations, measured from the deck level and at the hatch side girder. Brackets or deep webs shall be fitted to connect the upper stool to the deck transverse or hatch end beams. The upper stool of a transverse bulkhead shall be properly supported by deck girders or deep brackets between the adjacent hatch end beams. The width of the upper stool bottom plate shall generally be the same as that of the lower stool top plate. The stool top of non-rectangular stools shall have a width not less than twice the depth of corrugations. The ends of stool side ordinary stiffeners when fitted in a vertical plane, shall be attached to brackets at the upper and lower end of the stool. The stool shall be fitted with diaphragms in line with and effectively attached to longitudinal deck girders extending to the hatch end coaming girders or transverse deck primary supporting members. Scallops in the brackets and diaphragms in way of the connection to the stool bottom plate shall be avoided.

3.2 Net thickness of corrugation 3.2.1 Cold formed corrugation The net plate thickness t, in mm, of transverse vertically corrugated watertight bulkheads separating cargo holds shall not be less than:

Where:

sCW

= plate width, in mm, equal to the width of the corrugation flange a or the web c, whichever is greater as defined in Pt.3 Ch.3 Sec.6 Figure 11.

3.2.2 Built-up corrugation Where the thicknesses of the flange and web of built-up corrugations of transverse vertically corrugated watertight bulkheads separating cargo holds are different, the net plate thicknesses shall not be less than that obtained from the following formula. The net thickness tN, in mm, of the narrower plating shall not be less than:

sN

= plate width, in mm, of the narrower plating.

The net thickness tW, in mm, of the wider plating shall not be less than the greater of the following formulae:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 64

Part 5 Chapter 1 Section 4

3.1.3 Upper stool The upper stool, when fitted, shall have a height between two and three times the corrugation depth.

tNO

= net offered thickness of the narrower plating, in mm, shall not be greater than:

3.2.3 Lower part of corrugation The net thickness of the lower part of corrugations shall be maintained for a distance of not less than 0.15 ℓC measured from the top of the lower stool, or from the inner bottom where no lower stool is fitted. The span of the corrugations ℓC, in m, shall be as given in Figure 5. 3.2.4 Middle part of corrugation The net thickness of the middle part of corrugations shall be maintained for a distance not greater than 0.3 ℓC from the bottom of the upper stool, or from the deck if no upper stool is fitted. The net thickness shall also comply with the requirements in [3.3.1].

Figure 5 Parts of corrugation

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 65

Part 5 Chapter 1 Section 4

where:

Part 5 Chapter 1 Section 4

3.3 Bending, shear and buckling check 3.3.1 Bending capacity and shear capacity The bending capacity and the shear capacity of the corrugations of transverse watertight corrugated bulkheads separating cargo holds shall comply with the following formulae:

where:

M

= bending moment in a corrugation, in kNm:

FR

= resultant force, in kN, given in [2.2.8]

lC

= span of the corrugations, in m, as given in Figure 5

WLE = net section modulus, in cm3, of one half pitch corrugation at the lower end of the corrugations according to [3.4], shall not be greater than:

3

WG

= net section modulus, in cm , of one half pitch corrugation, in way of the upper end of shedder or gusset plates, as applicable, according to [3.4]

Q

= shear force, in kN, at the lower end of a corrugation, shall be:

hG

= height, in m, of shedders or gusset plates, as applicable as shown in Figure 6 to Figure 8

PR

= resultant pressure, in kN/m , in way of the middle of the shedders or gusset plates, as applicable, according to [2.2.8]

WM

= net section modulus, in cm , of one half pitch corrugation, at the mid-span of corrugations according to [3.4], but not greater than 1.15 WLE

τ

= shear stress, in N/mm , in the corrugation:

Ashr

= net shear area, in cm , of one half pitch corrugation. The calculated net shear area shall consider possible reduced shear efficiency due to non-straight angles between the corrugation webs and flanges. In general, the reduced shear area may be obtained by multiplying the web sectional area by sin φ

φ

= angle between the web and the flange, see Pt.3 Ch.3 Sec.6 Figure 11.

2

3

2

2

The net section modulus of the corrugations in the upper part of the bulkhead, as defined in Figure 5, shall not be less than 75% of that of the middle part complying with this requirement, corrected for different minimum yield stresses.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 66

Part 5 Chapter 1 Section 4

3.3.2 Shear buckling check of the bulkhead corrugation webs

The shear stress τ, calculated according to [3.3.1], shall comply with the following formula:

τ ≤ τC where:

τC

2

= critical shear buckling stress, in N/mm , shall be: for for 2

τE

= Euler shear buckling stress, in N/mm , shall be:

kt tw c

= coefficient, shall be equal to 6.34 = net thickness, in mm, of the corrugation webs = width, in mm, of the corrugation webs as shown in Pt.3 Ch.3 Sec.6 Figure 11.

3.4 Net section modulus at the lower end of the corrugations 3.4.1 Effective flange width The net section modulus at the lower end of the corrugations shall be calculated with the compression flange having an effective flange width beff not larger than the following formula:

where:

CE

= coefficient shall be equal to: for β > 1.25 for β ≤ 1.25

β

= coefficient shall be equal to:

a tf

= width, in mm, of the corrugation flange as shown in Pt.3 Ch.3 Sec.6 Figure 11 = net flange thickness, in mm.

3.4.2 Webs not supported by local brackets Unless welded to a sloping stool top plate as defined in [3.4.5], if the corrugation webs are not supported by local brackets below the stool top plate (or below the inner bottom) in the lower part, the section modulus of the corrugations shall be calculated considering the corrugation webs 30% effective.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 67

-3

but lower than 2.5 a tf ·10 where:

a tSH tf

= width, in mm, of the corrugation flange as shown in Pt.3 Ch.3 Sec.6 Figure 11 = net shedder plate thickness, in mm = net flange thickness, in mm.

Effective shedder plates are those which: — — — — —

are not knuckled are welded to the corrugations and the lower stool top plate according to Pt.3 Ch.13 Sec.1 [2.4.5] are fitted with a minimum slope of 45°, their lower edge being in line with the lower stool side plating have thickness not less than 75% of that required for the corrugation flanges have material properties not less than those required for the flanges.

Figure 6 Symmetrical and unsymmetrical shedder plates

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 68

Part 5 Chapter 1 Section 4

3.4.3 Effective shedder plates Provided that effective shedder plates are fitted as shown in Figure 6, when calculating the section modulus 2 at the lower end of the corrugations (sections 1 in Figure 6), the net area, in cm , of flange plates may be increased by ISH:

Part 5 Chapter 1 Section 4

Figure 7 Symmetrical and unsymmetrical gusset/shedder plates

Figure 8 Asymmetrical gusset/shedder plates 3.4.4 Effective gusset plates Provided that effective gusset plates are fitted, when calculating the section modulus at the lower end of the 2 corrugations (sections 1 in Figure 7 and Figure 8), the net area, in cm , of flange plates may be increased by the factor IG:

where:

hG

= height, in m, of gusset plates as shown in Figure 7 and Figure 8 but lower than:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 69

= width, in m, of gusset plates = net flange thickness, in mm

Effective gusset plates are those which: — are in combination with shedder plates having thickness, material properties and welded connections as requested for shedder plates in [3.4.3] — have a height not less than half of the flange width — are fitted in line with the lower stool side plating — are welded to the lower stool top plate, corrugations and shedder plates according to Pt.3 Ch.13 Sec.1 [2.4.5] — have thickness and material properties not less than those required for the flanges. 3.4.5 Corrugation web efficiency in way of sloping stool top plate Where the corrugation webs are welded to a sloping stool top plate which has an angle not less than 45º with the horizontal plane, the section modulus at the lower end of the corrugations may be calculated considering the corrugation webs fully effective. For angles less than 45º, the effectiveness of the web may be obtained by linear interpolation between 30% efficient for 0º and 100% efficient for 45º. Where effective gusset plates are fitted, when calculating the net section modulus of corrugations, the net area of flange plates may be increased as specified in [3.4.4] above. No credit will be given to shedder plates only.

3.5 Supporting structure in way of corrugated bulkheads 3.5.1 Lower stool a)

b)

c) d) e)

f)

The net thickness of the stool top plate shall not be less than that required for the attached corrugated bulkhead and shall be of at least the same material yield strength as the attached corrugation. The extension of the top plate beyond the corrugation shall not be less than the as-built flange thickness of the corrugation. The net thickness of the stool side plate, within the region of the corrugation depth from the stool top plate, shall not be less than the corrugated bulkhead flange net required thickness at the lower end and shall be of at least the same material yield strength. The net thickness may be reduced to 90% of corrugation flange thickness if continuity is provided between the corrugation web and supporting brackets inside the stool as defined in c). Continuity between corrugation web and lower stool supporting brackets shall be maintained inside the stool. Alternatively, lower stool supporting brackets inside the stool shall be aligned with every knuckle point of corrugation web. The net thickness of supporting bracket shall not be less than 80% of the required net thickness of the corrugation webs and shall be of at least the same material yield strength. The net thickness of supporting floors shall not be less than the net required thickness of the stool side plating (excluding the application of Grab requirements as defined in Pt.6 Ch.1 Sec.1) connected to the inner bottom and shall be of at least the same material yield strength. If material of different yield strength is used, the required thickness shall be adjusted by the ratio of the two material factors k. Where a lower stool is fitted, particular attention shall be given to the through-thickness properties, and arrangements for continuity of strength, at the connection of the bulkhead stool to the inner bottom. For requirements for plates with specified through-thickness properties, see Pt.3 Ch.3 Sec.1 [2.5].

3.5.2 Upper stool a)

The net thickness of the stool bottom plate shall not be less than that required for the attached corrugated bulkhead and shall be of at least the same material yield strength as the attached corrugation. The extension of the top plate beyond the corrugation shall not be less than the as-built flange thickness of the corrugation.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 70

Part 5 Chapter 1 Section 4

SGU tf

The net thickness of the lower portion of stool side plating shall not be less than 80% of the upper part of the bulkhead plating as required by [3.2], where the same material is used. If material of different yield strength is used, the required thickness shall be adjusted by the ratio of the two material factors k.

3.5.3 Local supporting structure in way of corrugated bulkheads without a lower stool a)

b)

c)

The net thickness of the supporting floors and pipe tunnel beams in way of a corrugated bulkhead shall not be less than the required net required thickness of the corrugation flanges and shall be of at least the same material yield strength. The inner bottom and hopper tank in way of the corrugation shall be of at least the same material yield strength as the attached corrugation, and Z grade steel as defined in Pt.3 Ch.3 Sec.1 [2.5] shall be used unless through thickness properties are documented. Brackets/carlings arranged in line with the corrugation web shall have a depth of not less than 0.5 times the corrugation depth and a net thickness not less than 80% of the net thickness of the corrugation webs and shall be of at least the same material yield strength. Where support is provided by gussets with shedder plates instead of brackets/carlings, the height of the gusset plate, see hG in Figure 6, shall be at least equal to the corrugation depth. The gusset plates shall be fitted in line with and between the corrugation flanges. The net thickness of the gusset and shedder plates shall not be less than 100% and 80%, respectively, of the net thickness of the corrugation flange and shall be of at least the same material yield strength. The plating of supporting floors shall be connected to the inner bottom by either full penetration or partial penetration weld.

3.6 Upper and lower stool subject to lateral flooded pressure 3.6.1 Yielding check of plating The net thickness, t in mm, of upper and lower stool plating shall not be less than required in Pt.3 Ch.6 Sec.4 2 [1.1], applying acceptance criteria AC-III and pressure Pbf-s, in kN/m , according to [2.2.6]. 3.6.2 Yielding check of stiffeners 3 The minimum net web thickness, in mm, and the minimum net section modulus, in cm , shall not be less 2 than required in Pt.3 Ch.6 Sec.5 [1.1], applying acceptance criteria AC-III and pressure Pbf-s, in kN/m , according to [2.2.6].

3.7 Corrosion addition 3.7.1 General The total corrosion addition, in mm, shall comply with the requirements given in Pt.3 Ch.3 Sec.3, but not less than the minimum corrosion addition given in [3.7.2]. 3.7.2 Minimum corrosion addition The minimum total corrosion addition, in mm, for both sides of the structural member shall be:

4 Allowable hold loading in flooded conditions 4.1 Evaluation of double bottom capacity and allowable hold loading 4.1.1 Shear capacity of the double bottom The shear capacity of the double bottom shall be calculated as the sum of the shear strength at each end of: — floors connected to hopper tanks, less one half of the shear strength of the two floors adjacent to each stool, or transverse bulkhead if no stool is fitted as shown in Figure 9. The shear strength of floors shall be calculated according to [4.1.2]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 71

Part 5 Chapter 1 Section 4

b)

The floors and girders to be considered when calculating the shear capacity of the double bottom are those inside the hold boundaries formed by the hopper tanks and stools or transverse bulkheads if no stool is fitted. Where both ends of girders or floors are not directly connected to the hold boundaries, their strength shall be evaluated for the connected end only. The hopper tank side girders and the floors directly below the connection of the stools or transverse bulkheads if no stool is fitted to the inner bottom may not be included. For special double bottom designs, the shear capacity of the double bottom shall be calculated by means of direct calculations carried out in accordance with requirements specified in Pt.3 Ch.7, as applicable. 4.1.2 Floor shear strength The floor shear strength, in kN, shall be as given in the following formulae: — in way of the floor panel adjacent to the hopper tank:

— in way of the openings in the outermost bay (i.e., that bay which is closer to the hopper tank):

where: 2

Af Af,h

= net sectional area, in mm , of the floor panel adjacent to the hopper tank

τA

= allowable shear stress, in N/mm , shall equal the lesser of:

2

= net sectional area, in mm , of the floor panels in way of the openings in the outermost bay (i.e. the bay which is closer to the hopper tank) 2

and

for floors adjacent to the stools or transverse bulkheads, τA is:

t s η1 η2

= floor web net thickness, in mm = spacing, in m, of stiffening members of the panel considered = coefficient shall be equal to 1.1 = coefficient shall be equal to 1.2. It may be reduced to 1.1 where appropriate reinforcements are fitted in way of the openings in the outermost bay, upon examination by the Society on a case-bycase basis.

4.1.3 Longitudinal girder shear strength The longitudinal girder shear strength, in kN, shall be as given in the following formulae: — in way of the longitudinal girder panel adjacent to the stool or transverse bulkhead, if no stool is fitted:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 72

Part 5 Chapter 1 Section 4

— double bottom girders connected to stools, or transverse bulkheads if no stool is fitted. The shear strength of girders shall be calculated according to [4.1.3].

2

Ag

= net sectional area, in mm , of the longitudinal girder panel adjacent to the stool (or transverse bulkhead, if no stool is fitted)

Ag,h

= net sectional area, in mm , of the longitudinal girder panel in way of the largest opening in the outermost bay (i.e. that bay which is closer to the stool) or transverse bulkhead, if no stool is fitted

τA η1 η2

= allowable shear stress, in N/mm , as defined in [4.1.2] where tN is the girder web net thickness

2

2

= coefficient shall be equal to 1.1 = coefficient shall be equal to 1.15. It may be reduced to 1.1 where appropriate reinforcements are fitted in way of the largest opening in the outermost bay, upon examination by the Society on a case-by-case basis.

4.1.4 Allowable hold loading The maximum mass of cargo in any cargo hold as given in the loading manual shall be less than the allowable hold loading, in t, shall be:

where:

ρC V F

3

= density of the dry bulk cargo, in t/m , as defined in [2.2.5] 3

= volume, in m , occupied by the cargo up to the level hB = coefficient shall be: F = 1.1 in general F = 1.05 for steel mill products

hB

= level of cargo, in m, shall be:

P

= pressure, in kN/m , shall be:

2

— for dry bulk cargoes, the lesser of:

— for steel mill products:

D1 hF

= distance, in m, from the baseline to the freeboard deck at side amidships

zF perm

= flooded level, in m, as defined in [2.3.2]

= inner bottom flooded height, in m, measured vertically with the ship in the upright position, from the inner bottom to the flooded level zF = permeability of cargo, may be lower than 0.3

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 73

Part 5 Chapter 1 Section 4

— in way of the largest opening in the outermost bay (i.e. that bay which is closer to the stool) or transverse bulk-head, if no stool is fitted:

= pressure, in kN/m , shall be equal to the lesser of:

CH

= shear capacity of the double bottom, in kN, calculated according to [4.1.1], considering, for each floor, the lesser of the shear strengths Sf1 and Sf2 as defined in [4.1.2] and, for each girder, the lesser of the shear strengths Sg1 and Sg2 as defined in [4.1.3]

ADB,H

= area, in m :

CE

= shear capacity of the double bottom, in kN, calculated according to [4.1.1], considering, for each floor, the shear strength Sf1 as defined in [4.1.2] and, for each girder, the lesser of the shear strengths Sg1 and Sg2 as defined in [4.1.3]

ADB,E

= area, in m :

n Si BDB,i

= number of floors between stools or transverse bulkheads, if no stool is fitted

BDB BDB,h s

2

2

= space of i-th floor, in m = length, in m, shall be equal to: B

DB,i

= BDB - s for floors for which Sf1 < Sf2

B

DB,i

= BDB,h for floors for which Sf1 ≥ Sf2

= breadth, in m, of double bottom between the hopper tanks as shown in Figure 10 = distance, in m, between the two openings considered as shown in Figure 10 = spacing, in m, of inner bottom longitudinal ordinary stiffeners adjacent to the hopper tanks.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 74

Part 5 Chapter 1 Section 4

2

Z

Part 5 Chapter 1 Section 4 Figure 9 Double bottom structure

Figure 10 Dimensions BDB and BDB,h

5 Vertical hull girder bending and shear strength in flooded conditions 5.1 Vertical hull girder bending strength 5.1.1 General The vertical hull girder bending strength requirements given in Pt.3 Ch.5 Sec.2 [1] shall be complied with using detailed requirements given in the following sub-sections. 5.1.2 Permissible still water bending moments for flooded conditions The permissible still water bending moments, in kNm, for flooded conditions in hogging and sagging shall comply with the following criteria:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 75

Msw

= permissible vertical still water bending moment, in kNm, for hogging and sagging, in seagoing condition at the hull transverse section being considered as defined in Pt.3 Ch.4 Sec.4 [2.2.2]. The bending moment Mwv used above shall have the same sign as the considered bending moment Msw-f.

5.2 Vertical hull girder shear strength of bulk carriers 5.2.1 Design criteria in flooded conditions The positive and negative permissible vertical still water shear force, in kN, in flooded conditions shall comply with the following criteria:

where:

Qsw

= permissible vertical still water shear force, in kN, positive and negative, in seagoing condition at the hull transverse section being considered as defined in Pt.3 Ch.4 Sec.4 [2.4.2].

The shear force Qwv used above shall have the same sign as the considered shear force Qsw-f. The vertical still water shear forces, in kN, for all loading conditions in flooded conditions, shall comply with the following criteria:

where:

ΔQmdf

= shear force correction, in kN, as defined in Sec.5 [5.2.4], in flooded conditions.

The shear force Qsw-f used above shall have the same sign as the considered shear force Qsw-Lcd-f.

5.3 Vertical hull girder shear strength of ore carriers 5.3.1 Design criteria in flooded conditions The positive and negative permissible vertical still water shear force, in kN, in flooded conditions shall comply with the following criteria:

where:

Qsw

= permissible vertical still water shear force, in kN, positive and negative, in seagoing condition at the hull transverse section being considered as defined in Pt.3 Ch.4 Sec.4 [2.4.2].

The shear force Qwv used above shall have the same sign as the considered shear force Qsw-f. The vertical still water shear forces, in kN, for all loading conditions in flooded conditions, shall comply with the following criteria:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 76

Part 5 Chapter 1 Section 4

where:

5.4 Hull girder ultimate strength check 5.4.1 General In addition to the hull girder ultimate strength check requirements given in Pt.3 Ch.5 Sec.4 for intact conditions, the same hull girder ultimate strength requirement applies to flooded conditions using hull girder ultimate bending loads in accordance with [5.4.2]. 5.4.2 Hull girder ultimate bending loads The vertical hull girder bending moment in hogging and sagging conditions, in kNm, to be considered in the ultimate strength check shall be:

where:

γS

= partial safety factor for the still water bending moment, shall be in accordance with Pt.3 Ch.5 Sec.4 [2.2.1]

γW

= partial safety factor for the vertical wave bending moment, shall be in accordance with Pt.3 Ch.5 Sec.4 [2.2.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 77

Part 5 Chapter 1 Section 4

The shear force Qsw-f used above shall have the same sign as the considered shear force Qsw-Lcd-f.

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2]. 2

aY

= transverse acceleration, in m/s , at the centre of gravity of the block load, for the considered load case, shall be obtained according to Pt.3 Ch.4 Sec.3 [3.2.2]

aZ

= vertical acceleration, in m/s , at the centre of gravity of the block load, for the considered load case, shall be obtained according to Pt.3 Ch.4 Sec.3 [3.2.3]

BtweenDk BTop fhar-M

= breadth of the cargo hold, in m, measured in way of the tweendeck hatch covers

fhar-Q

2

= breadth of the cargo hold, in m, measured in way of the weather deck hatch covers = wave correction factor for permissible vertical still water bending moment for harbour/ sheltered water operation, shall be:

fhar-M = 0.5 in general = wave correction factor for permissible vertical still water shear force for harbour/sheltered water operation, shall be: fhar-Q = 0.5 in general

ℓp Δz

= length of hatch cover, in m, in longitudinal direction

MH MIB

= cargo mass, in t, as defined in Sec.2

MDeck

= maximum block cargo mass, in t, on weather deck hatch covers in way of a cargo hold according to the design load plan

MtweenDk

= maximum block cargo mass, in t, on tween deck hatch covers in way of a cargo hold according to the design load plan

Msw

= permissible vertical still water bending moment for seagoing operation, in kNm, for hogging and sagging respectively at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [2.2.2]

Msw-p

= permissible vertical still water bending moment for harbour/sheltered water operation, in kNm, for hogging and sagging respectively at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [2.2.3]

Mwv

= vertical wave bending moment for seagoing operation, in kNm, for hogging and sagging respectively at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [3.1]

Pdl-s

= static pressure, in kN/m , due to distributed load on exposed decks as defined in Pt.3 Ch.4 2 Sec.5 [2.3.1], and static pressure, in kN/m , due to distributed load on inner bottom and tween decks as defined in Pt.3 Ch.4 Sec.6 [2.2.1]

PC

= static uniform cargo load, in kN/m , due to cargo loads on weather deck hatch covers, as defined in Pt.3 Ch.12 Sec.4 [2.3.1]

TB

= deepest ballast draught, in m, at mid-hold position of all ballast conditions, including ballast water exchange operation, in the loading manual

Qsw

= positive and negative permissible vertical still water shear force for seagoing operation, in kN, at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [2.4.2]

Qsw-p

= positive and negative permissible vertical still water shear force for harbour/sheltered water operation, in kN, at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [2.4.3]

= distance between the cargo's centre of gravity on hatch cover and the stopper locations, in m, in vertical direction = maximum block cargo mass, in t, on inner bottom in way of a cargo hold according to the design load plan

2

2

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 78

Part 5 Chapter 1 Section 5

SECTION 5 GENERAL DRY CARGO SHIPS AND MULTI-PURPOSE DRY CARGO SHIPS

= vertical still water shear force for the considered loading condition for seagoing operation, in kN, at the hull transverse section considered

Qsw-Lcd-p

= vertical still water shear force for the considered loading condition for harbour/sheltered water operation, in kN, at the hull transverse section considered

Qwv

= positive and negative vertical wave shear force in seagoing condition, in kN, at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [3.2]

ρc

= density of bulk cargo, in t/m .

3

1 Introduction 1.1 Introduction These rules apply to ships intended for carriage of various unitized and dry bulk cargo.

1.2 Scope This section describes requirements for arrangement and hull strength, including: — — — — — — — —

general arrangement design, see [2] structural design principles, see [3] loads, see [4] hull girder strength, see [5] hull local scantling, see [6] finite element analysis, see [7] buckling, see [8] fatigue, see [9].

1.3 Application 1.3.1 The rules given in this section apply to ships arranged for general cargo handling and intended for carriage of general unitized cargoes and dry cargoes in bulk. 1.3.2 These rules shall be applied to dry cargo ships intended for occasional carriage of dry cargoes in bulk and shall be assigned one of the ship type notations General dry cargo ship or Multi-purpose dry cargo ship.

2 General arrangement design 2.1 General The requirements given in [2.2] and [2.3] apply to ships intended for occasional carriage of dry cargoes in bulk.

2.2 Freeboard The ships shall have a freeboard of type B without reduced freeboard.

2.3 Double side skin construction Ships having a freeboard length LLL of not less than 100 m shall have a double side skin construction.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 79

Part 5 Chapter 1 Section 5

Qsw-Lcd

The requirements given in the following paragraphs apply to ships of double skin construction intended for occasional carriage of dry cargoes in bulk with freeboard length LLL of not less than 150 m. The minimum double side width shall not be less than 1 m measured perpendicular to the side shell. The minimum clearance between the inner surfaces of the stiffeners inside the double side shall not be less than: — 600 mm when the inner and/or the outer hulls are transversely stiffened — 800 mm when the inner and the outer hulls are longitudinally stiffened. Outside the parallel part of the cargo hold, the clearance may be reduced but shall not be less than 600 mm. The minimum clearance is defined as the shortest distance measured between assumed lines connecting the inner surfaces of the stiffeners on the inner and outer hulls.

3 Structural design principles 3.1 Corrosion protection of void double side skin spaces For ships intended for occasional carriage of dry cargoes in bulk with a freeboard length LLL of not less than 150 m, the void double side skin spaces in the cargo area shall have an efficient corrosion prevention system in accordance with SOLAS Chapter II-1, Part A-1 and IMO Resolution MSC.215(82) Performance standard for protective coatings for dedicated seawater ballast tanks in all types of ships and double-side skin spaces of bulk carriers(PSPC).

3.2 Structural arrangement 3.2.1 General The requirements given in Sec.2 [2] shall be complied with, where applicable. The requirement given in [3.2.2] applies to ships intended for occasional carriage of dry cargoes in bulk with a freeboard length LLL of not less than 150 m. The requirement given in [3.2.3] applies to ships with freeboard length LLL of not less than 150 m and 3 carrying solid bulk cargoes having a density 1.0 t/m and above. 3.2.2 Double side structure Primary stiffening structures of the double-side skin shall not be placed inside the cargo hold space. The double-side skin spaces, with the exception of top-side wing tanks, if fitted, shall not be used for the carriage of cargo. 3.2.3 Protection against wire rope Wire rope grooving in way of cargo holds openings shall be prevented by fitting suitable protection such as half-round bar on the hatch side girders (i.e. upper portion of top side tank plates) and hatch end beams in cargo hold and upper portion of hatch coamings.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 80

Part 5 Chapter 1 Section 5

2.4 Double side width

4.1 Standard design loading conditions 4.1.1 General The standard design loading conditions given in the following sub-sections shall be considered in addition to the standard loading conditions given in Pt.3 Ch.4 Sec.8 [1]. 4.1.2 Dry bulk cargo loading condition For ships intended for occasional carriage of dry cargoes in bulk, homogeneous cargo loaded condition shall be included in the loading manual where the cargo density corresponds to all cargo holds, including hatchways, being 100% full at scantling draught. 4.1.3 Alternate dry bulk cargo loading condition If the ship shall be strengthened for alternate dry bulk cargo loading, alternate loading condition shall be included in the loading manual with maximum cargo density at scantling draught. 4.1.4 Container loading condition For ships with container transporting capabilities on deck and/or in holds, homogeneous container loading condition shall be included in the loading manual at scantling draught. 4.1.5 Block loading condition If the ship shall be strengthened for block loading, block loading conditions shall be included in the loading manual. A block loading plan shall be submitted, specifying, where applicable, extent and magnitude of maximum block cargo hold mass on inner bottom, MIB, maximum block cargo mass on weather deck hatch covers, MDeck, and maximum block cargo mass on tween deck hatch covers, MtweenDk, including static pressure due to distributed loads. Guidance note: The following will be included in the appendix to the classification certificate, where applicable: —

extent and magnitude of maximum block cargo mass, in t, on inner bottom, weather deck hatch covers and tween deck hatch covers

—

2

static distributed loads, in t/m , on inner bottom, weather deck hatch covers and tween deck hatch covers. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.6 Heavy lifting operations in harbour/sheltered water If the ship shall be equipped with cranes intended for heavy lifting operations in harbour/sheltered water, heavy lifting loading conditions shall be included in the loading manual. The loading conditions shall represent crane operations giving the most unfavourable longitudinal strength results of vertical bending moments, vertical shear forces and torsional moments.

4.2 Loading conditions for primary supporting members 4.2.1 General The loading conditions for direct strength analysis of primary supporting members shall cover all loading conditions included in the loading manual, as required in Pt.3 Ch.4 Sec.8 [2] and [4.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 81

Part 5 Chapter 1 Section 5

4 Loads

Guidance note: Ships with L ≥ 150 m and minimum five cargo holds will be assigned a HC notation with standard FE design load combinations given in Pt.6 Ch.1 Sec.4 [4.2.8] for ballast loading conditions and dry bulk cargo loading conditions. For ships not assigned any HC notation, the standard FE design load combinations given in Pt.6 Ch.1 Sec.4 [4.2.8] for HC(M) ships may be used as guidance for ballast loading conditions and dry bulk cargo loading conditions. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.2.3 Containers on deck and/or in holds For ships intended for the carriage of containers in deck and/or in holds, the primary supporting members shall be strengthened with respect to container loading. For ships having a length L of not less than 150 m, with container transporting capabilities on deck and/or in holds, a homogeneous container load combination at scantling draught and with permissible still water hogging bending moment in seagoing condition will be required on a case-by-case basis. Guidance note: FE design load combination LC1 for Container ships given in Ch.2 Sec.6 Table 1 may be used as guidance for the dynamic load cases. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.2.4 Required loading pattern for ships having a long centre cargo hold For ships having a long centre cargo hold, and typically equipped with a short hold in fore area and/or aft area, maximum deflection of ship’s double-side and strengthening with respect to block loading needs shall be specially considered. Such ships may also be geared with cranes located in way of the ship’s double-side intended for heavy lifting operations with significant crane reactions that shall be assessed. The following seagoing loading patterns shall in general be considered, see also Table 1: a) b) c) d) e) f) g)

cargo hold carrying MIB with Pdl-s distributed at mid-length position, with no deck load, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC cargo hold carrying MIB with Pdl-s distributed at aft-length and fore-length position, with no deck load, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC deck carrying 0.8MDeck with PC distributed at mid-length position, with cargo hold carrying MIB - 0.8MDeck with tank top pressures distributed with the same longitudinal extent as on deck, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC deck carrying 0.8MDeck with PC distributed at aft-length and fore-length position, with cargo hold carrying MIB - 0.8MDeck with tank top pressures distributed with the same longitudinal extent as on deck, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC cargo hold carrying MH, with no deck load, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC cargo hold carrying 0.5MIB with tank top pressures applied to the whole inner bottom, with tween deck at highest position carrying MtweenDk with Pdl-s distributed at mid-length position, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC empty cargo hold, with no deck load, with all water ballast and fuel oil tanks in way of the cargo hold being 100% full, at the deepest ballast draught TB. The following additional harbour loading patterns shall be considered, see also Table 1:

h) i)

cargo hold carrying MIB with Pdl-s distributed at mid-length position, with no deck load, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC cargo hold carrying MIB with Pdl-s distributed at aft-length and fore-length position, with no deck load, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 82

Part 5 Chapter 1 Section 5

4.2.2 Dry cargoes in bulk For ships intended for occasional carriage of dry cargoes in bulk, design load combinations with dry bulk cargo loads shall be considered.

j)

cranes carrying SWL at maximum outboard outreach, with cargo hold being empty, with all anti heeling tanks at one side being 100% full, at 75% of scantling draught k) cranes carrying SWL at maximum inboard outreach, with cargo hold being empty, with all double bottom water ballast tanks in way of the cargo hold being 100% full, at 75% of scantling draught l) cranes carrying SWL at maximum outboard outreach, with cargo hold carrying 0.8MIB with Pdl-s distributed at aft-length and fore-length position, with all anti heeling tanks at one side being 100% full, at scantling draught TSC m) cranes carrying SWL at maximum inboard outreach, with cargo hold carrying 0.8MIB with Pdl-s distributed at aft-length and fore-length position, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC n) cranes carrying SWL at maximum outboard outreach, with cargo hold carrying 0.8MIB with Pdl-s distributed at mid-length position, with all anti heeling tanks at one side being 100% full, at scantling draught TSC o) cranes carrying SWL at maximum inboard outreach, with cargo hold carrying 0.8MIB with Pdl-s distributed at mid-length position, with all water ballast and fuel oil tanks in way of the cargo hold being empty, at scantling draught TSC.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 83

Part 5 Chapter 1 Section 5

If the ship is geared with cranes located in way of the ship’s double-side and intended for heavy lifting operations with SWL not less than 150 t per crane, the following additional loading patterns apply, see also Table 1:

Guidance note: Further explanations of the columns in Table 1 are given in DNVGL-CG-0127 Sec.3 [4.4]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

The design load combinations in Table 1 are representing block loading patterns, homogenous bulk loading pattern, crane loading patterns, and ballast loading pattern given in the loading manual in accordance with [4.2.4]. If the ship has a length L of not less than 150 m, with container transporting capabilities on deck and/or in holds, additional design load combination in accordance with [4.2.3] may be required on a case-bycase basis. If the loading manual is representing more decisive loading patterns than what is covered in [4.2.4], additional design load combinations will be required on a case-by-case basis. In Table 1 only loading patterns in way of the long centre cargo hold are shown. If the ship is equipped with a short hold in fore area and/or aft area adjacent to the long centre cargo hold that will be included in the FE model, the following applies in general: a) b)

c) d) e)

For loading patterns representing homogeneous loading conditions(e.g. homogeneous dry bulk cargo loading, ballast condition and container loading), the same loading patterns shall be applied the short hold in fore area and/or aft area as for the long centre cargo hold. For loading patterns representing block loading conditions, loading patterns shall be applied to the short hold in fore area and/or aft area giving the most unfavourable strength results of the double bottom in way of the long centre cargo hold. E.g. when the centre cargo hold has no block loading adjacent to the transverse bulkheads the adjacent holds shall have maximum loading, and when the centre cargo hold has block loading adjacent to the traverse bulkheads the adjacent holds shall be empty. For loading patterns representing crane lifting operations at partial draught with cranes outboard (with all cargo holds being empty and no deck load), all anti heeling tanks on one side shall be full. For loading patterns representing crane lifting operations at partial draught with cranes inboard (with all cargo holds being empty and no deck load), all double bottom ballast tanks in way of the short hold in fore area and/or aft area shall be full. For loading patterns representing crane lifting operations at scantling draught, loading patterns shall be applied to the short hold in fore area and/or aft area giving the most unfavourable strength results of the double bottom in way of the long centre cargo hold, see b). The same water ballast tank fillings shall be applied in way of the short hold in fore area and/or aft area as for in way of the long centre cargo hold.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 84

Part 5 Chapter 1 Section 5

4.2.5 Standard FE design load combinations for cargo hold analysis of a long centre cargo hold In Table 1 standard design load combinations for cargo hold FE analysis of a long centre cargo hold are shown.

DNV GL AS

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

Table 1 Standard FE design load combinations for cargo hold analysis of dry cargo ships with a long centre hold

No.

Description

Loading pattern Aft Mid Fore

Weights and tank content

Draught

% of perm. SWBM

% of perm. SWSF

Dynamic load case

Seagoing conditions

1

block loading mid [4.2.4] item a)

on deck: empty on inner bottom:

TSC

MIB at mid-length with Pdl-s

100% (sag.)

all ballast and FO tanks empty

100% Max SFLC

1)

100% Max SFLC

2)

≤100%

2

block loading aft and fore [4.2.4] item b)

on deck: empty on inner bottom:

TSC

MIB at aft and fore with Pdl-s

100% (hog.)

all ballast and FO tanks empty

100% Max SFLC

1)

100% Max SFLC

2)

≤100%

3

heavy deck loads mid [4.2.4] item c)

on deck: 0.8MDeck at mid-length with PC on inner bottom: MIB-0.8MDeck with same extent as PC

4

TSC

100% (sag.)

≤100%

MIB-0.8MDeck with same extent as PC all ballast and FO tanks empty

BSP-1P/ S HSM-2 FSM-2 HSM-2 FSM-2 BSP-1P/ S

BSP-1P/ S BSR-1P/ S

on deck: 0.8MDeck aft and fore with PC on inner bottom:

HSM-1 FSM-1

HSM-1 FSM-1

all ballast and FO tanks empty

heavy deck loads aft and fore [4.2.4] item d)

HSM-1 FSM-1

HSM-2 FSM-2 TSC

100% (hog.)

≤100%

BSP-1P/ S BSR-1P/ S

Page 85

Part 5 Chapter 1 Section 5

DNV GL AS

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

No.

Description

5

homogenous dry bulk cargo loading [4.2.4] item e)

6

heavy tween deck loading [4.2.4] item f)

Loading pattern Aft Mid Fore

Weights and tank content

Draught

% of perm. SWBM

TSC

75% (hog.)

TSC

75% (hog.)

on deck: empty in cargo hold: MH with ρc=1.0

% of perm. SWSF

≤100%

all ballast and FO tanks empty on tweendeck at highest position: MtweenkDk at mid-length with Pdl-s in cargo hold:

≤100%

0.5MIB applied to whole IB

Dynamic load case

HSM-2 FSM-2 BSP-1P/ S

HSM-2 FSM-2 BSP-1P/ S

all ballast and FO tanks empty

7

deepest ballast [4.2.4] item g)

on deck: empty in cargo hold:

HSM-2 FSM-2

TB

75% (hog.)

≤100%

TSC

100% (sag.)

≤100%

N/A

TSC

100% (hog.)

≤100%

N/A

empty all ballast and FO tanks full

BSP-1P/ S

Harbour conditions

8

block loading mid [4.2.4] item h)

on deck: empty on inner bottom: MIB at mid-length with Pdl-s all ballast and FO tanks empty

9

block loading aft and fore [4.2.4] item i)

on deck: empty on inner bottom: MIB at aft and fore with Pdl-s all ballast and FO tanks empty

Page 86

Part 5 Chapter 1 Section 5

DNV GL AS

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

No.

10

11

12

13

3)

3)

3)

3)

Description

crane outboard on partial draught [4.2.4] item j)

crane inboard on partial draught [4.2.4] item k)

crane outboard with Msw-p-h[4.2.4] item l)

crane inboard with Mswp-h[4.2.4] item m)

Loading pattern Aft Mid Fore

Weights and tank content

Draught

% of perm. SWBM

% of perm. SWSF

Dynamic load case

0.75TSC

100% (hog.)

≤100%

N/A

0.75TSC

100% (hog.)

≤100%

N/A

TSC

100% (hog.)

≤100%

N/A

TSC

100% (hog.)

≤100%

N/A

on deck: maximum crane moment and force on inner bottom: empty all anti heeling tanks at one side full, all other tanks empty on deck: maximum crane moment and force on inner bottom: empty all DB ballast tanks full, all other tanks empty on deck: maximum crane moment and force on inner bottom: 0.8MIB at aft and fore with Pdl-s all anti heeling tanks at one side full, all other tanks empty on deck: maximum crane moment and force on inner bottom: 0.8MIB at aft and fore with Pdl-s all ballast and FO tanks empty

Page 87

Part 5 Chapter 1 Section 5

DNV GL AS

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

No.

14

15

Description

3)

3)

Loading pattern Aft Mid Fore

crane outboard with Msw-p-s[4.2.4] item n)

crane inboard with Msw-ps[4.2.4]item o)

Weights and tank content

Draught

% of perm. SWBM

% of perm. SWSF

Dynamic load case

TSC

100% (sag.)

≤100%

N/A

TSC

100% (sag.)

≤100%

N/A

on deck: maximum crane moment and force on inner bottom: 0.8MIB at mid-length with Pdl-s all anti heeling tanks at one side full, all other tanks empty on deck: maximum crane moment and force on inner bottom: 0.8MIB at mid-length with Pdl-s all ballast and FO tanks empty

1)

The shear force shall be adjusted to target value at x < 0.5 L.

2)

The shear force shall be adjusted to target value at x > 0.5 L.

3)

Applicable for cranes with SWL ≥ 150t only.

Page 88

Part 5 Chapter 1 Section 5

5.1 Vertical hull girder bending strength 5.1.1 General The hull girder bending strength assessment shall in general be carried out in accordance with Pt.3 Ch.5 Sec.2 [1]. For harbour/sheltered water operation, the permissible still water bending moment criteria given in [5.1.2] shall be complied with, applying a wave correction factor for permissible vertical still water bending moment, fhar-M, differing from Pt.3 Ch.5 Sec.2. 5.1.2 Design criteria for harbour/sheltered water operation The permissible hull girder bending moment, in kN/m, for harbour/sheltered water operation in hogging and sagging shall comply with the following criteria:

The bending moment Mwv used above shall have the same sign as the considered bending moment Msw-p.

5.2 Vertical hull girder shear strength 5.2.1 General The hull girder shear strength assessment shall be carried out in accordance with Pt.3 Ch.5 Sec.2 [2] applying shear force correction given in [5.2.4]. Within the cargo hold region, shear force correction shall be applied to each loading condition given in the loading manual, and the loading/unloading sequences, where applicable. For ships having less than five cargo holds, the requirements for shear force correction given in [5.2.4] may be disregarded. For harbour/sheltered water operation, the permissible still water shear force criteria given in [5.2.3] shall be complied with, applying a wave correction factor for permissible vertical still water shear force, fhar-Q, differing from Pt.3 Ch.5 Sec.2. 5.2.2 Design criteria for seagoing operation The positive and negative permissible vertical still water shear force, in kN, for seagoing operation shall comply with the following criteria:

The shear force Qwv used above shall have the same sign as the considered shear force Qsw. The vertical still water shear forces, in kN, for all loading conditions for seagoing operation, shall comply with the following criteria:

where:

ΔQmdf

= shear force correction, in kN, as defined in [5.2.4], for seagoing operation.

The shear force Qsw used above shall have the same sign as the considered shear force Qsw-Lcd.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 89

Part 5 Chapter 1 Section 5

5 Hull girder strength

The shear force Qwv used above shall have the same sign as the considered shear force Qsw-p. The vertical still water shear forces, in kN, for all loading conditions for harbour/sheltered water operation, shall comply with the following criteria:

where:

ΔQmdf

= shear force correction, in kN, as defined in [5.2.4], for harbour/sheltered water operation.

The shear force Qsw-p used above shall have the same sign as the considered shear force Qsw-Lcd-p. 5.2.4 Shear force correction Shear force correction, which takes into account the portion of loads transmitted by the double bottom longitudinal girders to the transverse bulkheads, shall be considered. For the considered cargo hold, the shear force correction at the considered transverse section shall be obtained, in kN, from the following formula:

where:

Cd

= distribution coefficient: — — — —

Cd = -1 at the aft end of the considered cargo hold Cd = 1 at the fore end of the considered cargo hold Cd = linearly distributed inside the considered cargo hold Cd = 0 at the fore bulkhead of the foremost cargo hold, at the aft bulkhead of the aftmost cargo hold and in the middle of the foremost and the aftmost cargo hold.

α

= coefficient:

M

= mass, in t, in the hold in way of the considered transverse section for the considered loading condition. M shall include the mass of ballast water and fuel oil located directly below the flat portion of the inner bottom, if any, excluding the portion under the bulkhead stool, if any

BH lH l0, b0

= breadth of the cargo hold, in m, as defined in [2] = length of the cargo hold, in m, as defined in [2] = length and breadth, respectively, in m, of the flat portion of the double bottom in way of the hold considered; b0 shall be measured on the hull transverse section at the middle of the hold

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 90

Part 5 Chapter 1 Section 5

5.2.3 Design criteria for harbour/sheltered water operation The positive and negative permissible vertical still water shear force, in kN, for harbour/sheltered water operation shall comply with the following criteria:

Part 5 Chapter 1 Section 5

but not greater than 3.7

TLC,mh

= draught, in m, measured vertically on the hull transverse section at the middle of the hold considered, from the moulded baseline to the waterline in the loading condition considered

ΔQCF ΔQCE

= shear force correction for the full hold = shear force correction for the empty hold.

Figure 1 Shear force correction, ΔQC

5.3 Loading instrument 5.3.1 General Ships intended for occasional carriage of dry cargoes in bulk, having a freeboard length LLL not less than 150 m, shall be fitted with a loading instrument capable of providing information on hull girder shear forces and bending moments in accordance with the requirements given in Pt.3 Ch.1 Sec.5 [3]. Guidance note: The requirement given above is in accordance with SOLAS reg.XII/11.1, as referred to in IMO resolution MSC.277(85). See also Pt.3 Ch.1 Sec.5 [3.1.1] for main class requirements to required installation of loading instrument. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

For ships intended for occasional carriage of dry cargoes in bulk, having a freeboard length LLL less than 150 m, the loading instrument shall be capable of providing information on the ship's stability in intact conditions in accordance with the requirements given in Pt.3 Ch.15 Sec.1 [4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 91

5.3.3 Ships applying shear force correction upon vertical hull girder shear strength assessment For ships applying shear force correction upon vertical hull girder shear strength assessment in accordance with [5.2.4], the loading instrument shall provide hull girder shear strength results, including shear force correction.

6 Hull local scantling 6.1 Plating 6.1.1 Plating subject to lateral pressure For ships intended for occasional carriage of dry cargoes in bulk the requirements given in Pt.3 Ch.6 Sec.4 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1].

6.2 Stiffeners 6.2.1 Stiffeners subject to lateral pressure For ships intended for occasional carriage of dry cargoes in bulk the requirements given in Pt.3 Ch.6 Sec.5 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1].

6.3 Primary supporting members 6.3.1 General For primary supporting members not assessed in accordance with [7.2], the requirements given in Pt.3 Ch.6 Sec.6 [2] shall be complied with, applying the loading conditions for PSM given in [4.2], with the additional design load sets given in Sec.2 [5.1].

6.4 Intersection of stiffeners and primary supporting members 6.4.1 Connection of stiffeners to primary supporting members For ships intended for occasional carriage of dry cargoes in bulk the requirements for connection of stiffeners to primary supporting members shall comply with Pt.3 Ch.6 Sec.7 [1], including the internal pressure due to dry bulk cargo given in Sec.2 [3].

6.5 Fixed cargo securing devices 6.5.1 Supporting structures of fixed cargo securing devices Stiffeners and girders supporting fixed cargo securing devices shall comply with the requirements given in Pt.3 Ch.6 Sec.5 and Pt.3 Ch.6 Sec.6, applying the certified MSL (Maximum Securing Load) with the acceptance criteria AC-II.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 92

Part 5 Chapter 1 Section 5

5.3.2 Ships with a long centre cargo hold For ships with a long centre cargo hold, information on torsional moments shall be included in the loading instrument.

7.1 Global strength analysis 7.1.1 General For ships equipped with cranes for heavy lifting operations and with a long centre cargo hold, a global strength analysis may be required on a case-by-case basis. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0151 Strength analysis of general cargo and multi-purpose dry cargo ships. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.2 FE load combinations The load combinations to be applied to the global FE model are defined in DNVGL-CG-0151 Sec.2 [2.1]. 7.1.3 Wave load analysis The wave load analysis shall be based on all wave headings (0° to 360°). For ships with symmetric cross sections, it is sufficient to consider wave directions from one side only. The spacing between the headings shall not be greater than 30°. Speed, design wave amplitude and probability level to be applied in the wave load analysis are given in Table 2. Table 2 Speed, design wave amplitude and probability level Limit state fatigue strength (FLS) ultimate strength (ULS)

Basis for design 1) wave amplitude

Speed 2)

2/3 of service speed

Mwv

5 knots

Load level -2

probability of excess

-8

probability of excess

10

Mwv with fp = 1.0

10

1)

Methods how to establish design wave amplitude are further outlined in DNVGL-CG-0151 Sec.2 [2].

2)

Mwv as defined in Pt.3 Ch.4 Sec.4.

7.1.4 Finite element analysis The focus of the global strength analysis for a ship with a long centre cargo hold is on the evaluation of global stresses and deformations under particular consideration of torsional response. Furthermore, effects of the integrated crane columns into the ship structure shall be investigated. Characteristics and application of different structural model types are given in Table 3. Table 3 Required FE models Model type

Characteristics

Applications

3)

— boundary conditions for sub-models global FE model

1)

— the whole structure of the vessel — girder or stiffener spaced mesh — includes mass-model

— yield strength and buckling assessment of strength members — nominal stress for fatigue strength assessment in combination with FAT classes

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 93

Part 5 Chapter 1 Section 5

7 Finite element analysis

local model

2)

Characteristics

Applications

3)

fatigue assessment of:

— fine mesh — sub-model or local fine mesh area in global FE model

— hatch corners — transition area between crane columns and the ship structure

1)

Detailed modelling principles are further outlined in DNVGL-CG-0127 Sec.1 [2] and DNVGL-CG-0151 Sec.2 [1].

2)

Detailed modelling principles are further outlined in DNVGL-CG-0131 Sec.2 [2].

3)

Fatigue application are further outlined in DNVGL-CG-0131 Sec.2 [2].

7.1.5 Fatigue critical details Fatigue critical details that shall be assessed, are given in Table 4. Table 4 Overview of fatigue critical details Detail

Location

knuckles and discontinuities of longitudinal members in upper part of hull girder — transition areas between crane columns and the ship structure

all locations within the cargo hold region(s)

Stress type used for 1) fatigue assessment nominal stress from global FE model in combination with FAT classes or hot spot stress 2) concentration factors hot spot or local stress from local model

— hatch corners 1)

Fatigue assessments are further outlined in DNVGL-CG-0131 Sec.2 [2].

2)

In exceptional cases, e.g. pronounced secondary bending, assessment with a local model can be required by the Society on a case-by case basis.

7.1.6 Fatigue strength assessment The fatigue strength assessment shall be carried out in accordance with Pt.3 Ch.9 Sec.4 for fatigue critical details specified in [7.1.5]. Total fatigue damage shall be determined on basis of seagoing loading patters and the crane in harbour combinations given in [7.1.2]. The fraction f0 of the total design life spent at sea should be assumed according to Pt.3 Ch.9 Sec.4 Table 2. For all seagoing loading patterns as given in [7.1.2], an equal fraction of the design fatigue shall be assumed. The maximum stress range of each loading pattern shall be considered. Additional fatigue damage is caused by harbour operations. Therefore maximum stress shall be derived from all crane in harbour combinations. Unless otherwise specified by designer, relevant load spectrum and number of load cycles are defined in DNVGL-ST-0377 Table 5-7. For assessment of the fatigue critical details (see Table 4) it is not required that ballast tanks shall comply with the tank filling requirements according to Pt.3 Ch.9 Sec.4 Table 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 94

Part 5 Chapter 1 Section 5

Model type

Table 5 Permissible stresses for global element analysis Permissible axial & principal stress

Permissible von Mises stress

Permissible shear stress

AC-II

AC-I

AC-II

AC-I

AC-II

AC-I

seagoing

harbour

seagoing

harbour

seagoing

harbour

girder spaced mesh

195/k

156/k

120/k

96/k

215/k

172/k

stiffener spaced mesh when provided

220/k

176/k

130/k

104/k

235/k

188/k

7.1.8 Buckling capacity For plating of all hull girder structural members, primary supporting structural members and bulkheads, a verification for harbour and seagoing conditions against the buckling criteria shall be carried out in accordance with Pt.3 Ch.8 Sec.4. For girder spacing mesh with a partial safety factor of S = 1.05, and for stiffener spacing with a partial safety factor of S = 1.0.

7.2 Cargo hold analysis 7.2.1 General Cargo hold analysis shall be carried out in accordance with Pt.3 Ch.7 Sec.1 and Pt.3 Ch.7 Sec.3 using detailed requirements given in the following sub-sections. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0127 Finite element analysis. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: Ships with L ≥ 150 m and minimum five cargo holds will be assigned a HC notation with additional requirements for cargo hold analysis given in Pt.6 Ch.1 Sec.4 [7.1] and requirements for local structural strength analysis given in Pt.6 Ch.1 Sec.4 [7.2]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.2.2 Application Cargo hold analysis of midship region is mandatory irrespective of the ship’s length. For ships with a long centre cargo hold, only cargo hold analysis of the long centre hold is mandatory. Cargo hold analysis of short holds in fore area and/or aft area, if any, is not mandatory.. 7.2.3 Extent of model For ships with a long centre cargo hold and not equipped with a short hold in fore area and aft area, the required longitudinal extent of the model will be considered on a case-by-case basis. Guidance note: The minimum extent of the model should be from the engine room front bulkhead to the long centre hold front bulkhead. The evaluation area will then typically be limited to within 75% of the model length. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 95

Part 5 Chapter 1 Section 5

7.1.7 Yield capacity Stresses in plating of all hull girder structural members, primary supporting structural members and bulkheads shall not exceed the permissible values as given in Table 5:

For evaluation of all structural members within the centre cargo hold, including transverse bulkheads, the following modelling should be applied: —

if the long centre cargo hold is adjacent to the machinery spaces (with no short hold in the aft area), the typical extension of an aftmost cargo hold model into the machinery spaces outlined in DNVGL-CG-0127 Finite element analysis, may be used as guidance

—

if the long centre cargo hold is adjacent to the fore peak (with no short hold in the fore area), the typical extension of an foremost cargo hold model into the fore peak outlined in DNVGL-CG-0127 Finite element analysis, may be used as guidance. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

For ships equipped with cranes located in way of the ship’s double-side and intended for heavy lifting operations, the lower portion of the crane pedestals extending up to the connecting flange to the slewing bearing shall be included in the model. 7.2.4 FE load combinations The load combinations to be applied to the FE model shall be based on the required design load combinations for direct strength analysis of PSM given in [4.2]. 7.2.5 Loads due to dry bulk cargo Bulk pressures and shear loads, where applicable, shall be applied to the FE model in accordance with Sec.2 [3]. 7.2.6 Loads due to block loading on inner bottom Where applicable, static and dynamic pressure loads due to block cargo mass, MIB in t, acting on the inner bottom shall be applied to the inner bottom as follows: 2

— in harbour conditions, static pressures, Pdl-z in kN/m , in vertical direction (positive downward to the plating), shall be:

2

— in seagoing conditions, static and dynamic pressures, Pdl-z in kN/m , in vertical direction (positive downward to the plating), shall be:

2

— in seagoing conditions, dynamic shear pressures, Pdl-y in kN/m , in transverse direction (positive to port), shall be:

Shear pressures in longitudinal direction may be omitted. 7.2.7 Loads due to block loading on tween deck hatch covers Where applicable, static and dynamic forces and tipping moments due to block cargo mass, MtweenDk in t, acting on tween deck hatch covers, shall be applied in way of the hatch cover pockets at the relevant stopper locations. For a typical arrangement with four active stoppers in z direction and two in y direction for each hatch cover, forces shall be applied as follows: — in harbour conditions, static forces, Fdl-z in kN, in vertical direction (positive downward on both sides), shall be:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 96

Part 5 Chapter 1 Section 5

Guidance note:

— in seagoing conditions, dynamic forces, Fdl-y in kN, in transverse direction (for BSR-1P and BSP-1P on port side only and positive to port), shall be:

Forces in longitudinal direction may be omitted. 7.2.8 Loads due to block loading on weather deck hatch covers Where applicable, static and dynamic forces and tipping moments due to block cargo mass, MDeck in t, acting on weather deck hatch covers, shall be applied at the relevant stopper locations. For typical arrangement with four active stoppers in z direction and one in y direction for each hatch cover, forces shall be applied as follows: — in harbour conditions, static forces, FC-z in kN, in vertical direction (positive downward on both sides), shall be:

— in seagoing conditions, static and dynamic force FC-z in kN, in vertical direction (positive downward on both sides), shall be:

— in seagoing conditions, dynamic force, FC-y in kN, in transverse direction (typically on the side where ship cranes are arranged), shall be:

Forces in longitudinal direction can be omitted. 7.2.9 Crane loads If the ship is equipped with cranes located in way of the ship’s double-side and intended for heavy lifting operations, forces and bending moments shall be applied to the crane pedestals in accordance with Pt.3 Ch.11 Sec.2 [4]. A dynamic factor, ψ, specified by the designer and being less than given in Pt.3 Ch.11 Sec.2 [4.5.1] will be considered on a case-by-case basis. 7.2.10 Container loads Container loads, where applicable, shall be applied to the FE model in accordance with DNVGL-CG-0131 Sec.2 [1.3.3].

7.3 Embedded cargo hold analysis 7.3.1 General The cargo hold FEA according to [7.2] may be carried out with the global FE-model, when the mesh size in mid ship area corresponds with the stiffener spacing as described in DNVGL-CG-0127 Sec.3 [2.2.4]. 7.3.2 Direct wave analysis Based on the load procedure described in DNVGL-CG-0131 Sec.2 [1], the required load combinations given in -8 [4.2] shall be generated by direct wave analysis for a 10 probability level of exceedance.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 97

Part 5 Chapter 1 Section 5

— in seagoing conditions, static and dynamic forces, Fdl-z in kN, in vertical direction (positive downward on both sides), shall be:

8 Buckling 8.1 Hull girder buckling For ships intended for occasional carriage of dry cargoes in bulk, the requirements given in Pt.3 Ch.8 Sec.3 shall be complied with, applying the additional design load sets given in Sec.2 [5.1].

9 Fatigue 9.1 General 9.1.1 Fatigue assessment shall be carried out for ships having a length L of not less than 90 m in accordance with Pt.3 Ch.9, using detailed requirements in the following sub-sections. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0129 Fatigue assessment of ship structure. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9.2 Prescriptive fatigue strength assessment Within the cargo region, the following details shall be considered in accordance with DNVGL-CG-0129 Fatigue assessment of ship structure: — end connections of longitudinal stiffeners to transverse web frames and transverse bulkheads shall fulfill relevant requirements of DNVGL-CG-0129 Sec.4 — other welded details, e.g. transverse butt welds, hatch cover resting pads, equipment holders etc. in the upper part of the hull girder shall fulfill relevant requirements of DNVGL-CG-0129 Sec.3 [5] — knuckles and discontinuities of longitudinal structural members, e.g. hatch coamings, in the upper part of the hull girder, according to DNVGL-CG-0129 Sec.3 [5].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 98

Part 5 Chapter 1 Section 5

Inside of the investigated cargo hold the loading patterns shall be in alignment with [4.2.5]. Outside of this hold the loading patterns can be adjusted in such a way, that the required draught and still water bending moment can be fulfilled on an even trim.

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2].

1 Introduction 1.1 Introduction These rules apply to ships primarily intended for the carriage of solid bulk cargoes.

1.2 Scope This section describes requirements for arrangement and hull strength.

1.3 Application 1.3.1 These rules are applicable to sea-going single deck ships with cargo holds of single and or double side skin construction, with a double bottom, hopper side tanks and top-wing tanks fitted below the upper deck, and intended for the carriage of solid bulk cargoes. Typical cargo hold cross-sections are given in Figure 1.

Figure 1 Typical hold cross-sections a) single side skin bulk carrier b) double side skin bulk carrier 1.3.2 These rules are also applicable to ships primarily intended for the carriage of solid bulk cargoes with other arrangements than shown in Figure 1. Such ships shall have full SOLAS Ch. XII compliance and will be defined as a bulk carrier in the SOLAS Cargo Ship Safety Construction Certificate. 1.3.3 Ships complying with the requirements given in this section will be assigned the ship type class notation Bulk carrier.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 99

Part 5 Chapter 1 Section 6

SECTION 6 BULK CARRIERS

2.1 CSR Bulk carriers 2.1.1 Bulk carriers having a length L of 90 m and above and having at least one cargo hold with crosssections as given in Figure 1 shall comply with CSR Pt.1 and CSR Pt.2 Ch.1. Applicable requirements of Pt.3 are listed in Pt.3 Ch.1 Sec.1 [1.1.2]. The following requirements given in Ch.1 are applicable: — Sec.1 — Sec.2 [6]. 2.1.2 For regions of the structure for which CSR Pt.1 and CSR Pt.2 Ch.1 do not apply, the appropriate classification rules shall be applied. In cases where CSR Pt.1 and CSR Pt.2 Ch.1 do not address certain aspects of the ship's design, the applicable classification rules shall be applied. 2.1.3 For ships of gross tonnage 20 000 dwt and above, access to and within spaces in, and forward of, the cargo area shall comply with SOLAS Regulation II-1/3-6 and IACS UI SC191.

2.2 Non-CSR Bulk carriers 2.2.1 Ships having a typical cargo hold cross-sections as given in Figure 1 and having a length L of less than 90 m shall comply with Sec.5, including the requirements for ships intended for occsional carriage of dry cargoes in bulk, with the following additional requirements: — — — — —

the general arrangement requirements given in Sec.5 [2.2] and Sec.5 [2.3] are not applicable the requirements for forecastle given in Sec.7 [2.1] shall be complied with cargo hatch covers shall be designed in accordance with CSR Pt.2 Ch.1 Sec.5 cargo hold spaces shall have corrosion protection in accordance with CSR Pt.2 Ch.1 Sec.2 [2.3] structural detail principles to single side structure, if any, shall be in accordance with CSR Pt.2 Ch.1 Sec.2 [3.2] — strength requirements for single side frames, if any, shall be in accordance with CSR Pt.2 Ch.1 Sec.3 [1], applying pressures and design load sets in accordance with Sec.2 [5.1], with αm and αS in accordance with Sec.2 [5.2.2] — for ships having a gross tonnage not of less than 20,000, the requirements for permanent means of access given in Sec.7 [2.2] shall be complied with. 2.2.2 Ships assigned the ship type notation Bulk carrier in accordance with [1.3.2] shall be built in compliance with Sec.5, including the requirements for ships intended for occasional carriage of dry cargoes in bulk. The general arrangement requirements given in Sec.5 [2.2] and Sec.5 [2.3] are not mandatory.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 100

Part 5 Chapter 1 Section 6

2 Hull strength and arrangement

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2].

fhar Msw-p

= wave correction factor for harbour/sheltered water operation, as defined in Pt.3 Ch.5 Sec.2

Qwv-LC

= vertical wave shear force for seagoing operation, in kN, at the hull transverse section considered for the considered dynamic load case, as defined in Pt.3 Ch.4 Sec.4 [3.5.3]

Qsw

= positive and negative permissible vertical still water shear force for seagoing operation, in kN, at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [2.4.2]

Qsw-p

= positive and negative permissible vertical still water shear force for harbour/sheltered water operation, in kN, at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [2.4.3]

Qwv

= positive and negative vertical wave shear force for seagoing operation, in kN, at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [3.2].

= permissible vertical still water bending moment for harbour/sheltered water operation, in kN, for hogging and sagging respectively at the hull transverse section being considered, as defined in Pt.3 Ch.4 Sec.4 [2.2.3]

1 Introduction 1.1 Introduction These rules apply to ships primarily intended for the carriage of ore cargoes.

1.2 Scope This section describes requirements for arrangement and hull strength, including: — — — — — — — — —

general arrangement design, see [2] structural design principles, see [3] loads, see [4] hull girder strength, see [5] hull local scantling, see [6] finite element analysis, see [7] buckling, see [8] fatigue, see [9] hatch covers and hatch coamings, see [10].

1.3 Application 1.3.1 These rules are applicable to vessels with the following characteristics: 3

— primarily intended to carry ore cargoes in dry bulk with density up to 3 t/m , e.g. iron ore — sea-going single deck ships having two longitudinal bulkheads and a double bottom throughout the cargo region — intended for carrying ore cargoes in the centre holds only, as indicated in Figure 1.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 101

Part 5 Chapter 1 Section 7

SECTION 7 ORE CARRIERS

Part 5 Chapter 1 Section 7

Figure 1 Typical midship section of ore carrier 1.3.2 Ships complying with the requirements given in this section will be assigned the ship type class notation Ore carrier.

2 General arrangement design 2.1 Forecastle 2.1.1 An enclosed forecastle shall be fitted on the freeboard deck. The aft bulkhead of the enclosed forecastle shall be fitted in way or aft of the forward bulkhead of the foremost hold, as shown in Figure 2. However, if this requirement hinders hatch cover operation, the aft bulkhead of forecastle may be fitted forward of the forward bulkhead of the foremost cargo hold, provided that the forecastle length is not less than 0.07 LLL abaft the fore side of the stem.

Figure 2 Forecastle arrangement 2.1.2 The forecastle height, HF, above the main deck shall not be less than the greater of the following values: — the standard height of a superstructure as specified in Pt.3 Ch.1 Sec.4 [3.3] — HC + 0.5 m, where HC is the height of the forward transverse hatch coaming of the foremost cargo hold, i.e. cargo hold number 1.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 102

from the hatch coaming plate. 2.1.4 A wave breaker shall not be fitted on the forecastle deck with the purpose of protecting the hatch coaming or hatch covers. If fitted for other purposes, it shall be located such that its upper edge at centreline is not less than HB / tan 20° forward of the aft edge of the forecastle deck, where HB is the height of the wave breaker above the forecastle, see Figure 2. Guidance note: The hatch coamings and the hatch covers will be strengthened in accordance with [10] even if a wave breaker is fitted according to the above requirement. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2 Access arrangement 2.2.1 Ship structure access manual Ship structures subject to overall and close-up inspection and thickness measurements shall be provided with means of access in accordance with SOLAS, Ch II-1, Reg 3-6, which shall be described in a ship structure access manual.

3 Structural design principles 3.1 Corrosion protection of wing void spaces For ore carriers with a freeboard length LLL of not less than 150 m, wing void spaces in the cargo area shall have an efficient corrosion prevention system, such as hard protective coatings or equivalent. Guidance note: The flag administration may require that the wing void spaces shall be considered as double skin void spaces that shall comply with SOLAS Chapter II-1, Part A-1, Regulation 3-2 and IMO Resolution MSC.215(82) Performance standard for protective coatings for dedicated seawater ballast tanks in all types of ships and double-side skin spaces of bulk carriers(PSPC). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2 Structural arrangement - cargo hold region 3.2.1 General The requirements given in Sec.2 [2] shall be complied with, where applicable. The requirements given in [3.2.2] and [3.2.3] apply to ore carriers with a freeboard length LLL of not less than 150 m. 3.2.2 Double side structure Primary stiffening structures of the double-side skin shall not be placed inside the cargo hold space. The double-side skin spaces shall not be used for the carriage of cargo.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 103

Part 5 Chapter 1 Section 7

2.1.3 All points of the aft edge of the forecastle deck shall be located at a distance less than or equal to:

3.3 Structural arrangement - fore peak structure 3.3.1 Arrangement of floors Where transverse stiffening is applied, floors shall be fitted at each web frame location. Where longitudinal stiffening is applied, the spacing of floors shall not be greater than 4.5 m or five transverse frame spacings, whichever is smaller. The depth of the floors shall not be less than the height of the double bottom in the foremost cargo hold and the upper edge shall be stiffened. 3.3.2 Arrangement of bottom girders The fore peak shall be fitted with a centreline girder and side girders. The transition (scarfing) of the longitudinal bulkhead shall be connected to a side girder. Where transverse stiffening is applied, the spacing of bottom girders shall not exceed 2.5 m. Where longitudinal stiffening is applied, the spacing of bottom girders shall not exceed 3.5 m. The depth of the bottom girders shall not be less than the height of the double bottom in the foremost cargo hold and the upper edge shall be stiffened. 3.3.3 Centreline bulkhead Alternatively to the requirements for longitudinal girders given in [3.3.2] a perforated centreline bulkhead may be fitted supporting all floors in the fore peak, and extending not less than two platform decks/stringer levels above the inner bottom. 3.3.4 Arrangement of side web frames The spacing of side web frames in the fore peak shall not be greater than 4.5 m or five transverse frame spacings, whichever is smaller. 3.3.5 Support of chain locker The chain lockers shall be supported by the ship's side or the fore peak bulkhead by minimum two partial bulkheads.

3.4 Structural arrangement - machinery space 3.4.1 Arrangement of side girders The spacing of side web frames in the engine room shall not be greater than 4.5 m or five transverse frame spacings, whichever is smaller. Web frames shall be connected at the top and bottom to members of suitable stiffness, and supported by deck transverses. 3.4.2 Support of heavy fuel oil tanks Partial end bulkheads forming the boundary of heavy fuel oil storage tanks shall extend down to the outer shell with vertical stiffening. 3.4.3 Termination of longitudinal bulkhead The longitudinal bulkhead shall continue inside the machinery space for a distance not less than 4.5 m or five transverse frame spacings, whichever is greater, before starting the tapering of the bulkhead structure, e.g. scarfing brackets.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 104

Part 5 Chapter 1 Section 7

3.2.3 Protection against wire rope Wire rope grooving in way of cargo holds openings shall be prevented by fitting suitable protection such as half-round bar on the hatch side girders (i.e. upper portion of top side tank plates) and hatch end beams in cargo hold and upper portion of hatch coamings.

4 Loads 4.1 Standard design loading conditions 4.1.1 General The standard design loading conditions given in [4.1.2] shall be considered in addition to the standard loading conditions given in Pt.3 Ch.4 Sec.8 [1]. 4.1.2 Ore cargo loading condition Homogeneous cargo loaded condition shall be included in the loading manual where the cargo density is 3 equal to 3.0 t/m in all cargo holds at scantling draught.

4.2 Loading conditions for primary supporting members 4.2.1 General The loading conditions for direct strength analysis of primary supporting members shall envelope all loading conditions included in the loading manual, as required in Pt.3 Ch.4 Sec.8 [2] and [4.1]. Guidance note: Ore carriers with L ≥ 150 m will be assigned an OC notation with standard FE design load combinations given in Pt.6 Ch.1 Sec.5 [4.2.8] for ballast and cargo loaded loading conditions, and loading/unloading sequences. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5 Hull girder strength 5.1 Vertical hull girder shear strength 5.1.1 General The hull girder shear strength assessment shall in general be carried out in accordance with Pt.3 Ch.5 Sec.2 [2]. Within the cargo hold region, the shear force correction shall be accounted for when establishing the total hull girder shear force capacity in accordance with [5.1.2]. 5.1.2 Total hull girder shear capacity The total vertical hull girder shear capacity, in kN, is the minimum of the calculated values for all plates i contributing to the hull girder shear of the considered transverse section and shall be obtained by the following formula:

where:

qvi-gr ti-gr

-1

= unit shear flow, in mm , for the plate i based on gross thickness, as defined in Pt.3 Ch.5 Sec.2 = gross thickness, in mm, for plate i. For longitudinal bulkheads within the cargo hold region, ti-gr shall be equal to tsfi-gr

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 105

Part 5 Chapter 1 Section 7

The longitudinal bulkhead inside the machinery space shall have the same hull girder shear strength, i.e. same net plate thickness and yield strength, as that required immediately in front of the engine room bulkhead according to [5.1].

= permissible shear stress, in N/mm , for plate i, shall be:

For longitudinal bulkhead the gross thickness of the plating above the inner bottom, tsfi-gr for plate i, in mm, is given by:

where:

tΔi

= thickness deduction for plate i, in mm.

The vertical distribution of thickness reduction for shear force correction shall be triangular as indicated in Figure 3. The thickness deduction, tΔi in mm, to account for shear force correction on the plate i, shall be:

where:

δQ3 ℓh hblk

= shear force correction for longitudinal bulkhead as defined in [5.1.3], in kN

xblk

= minimum longitudinal distance from section considered to the nearest cargo hold transverse bulkhead, in m. Shall be positive and not greater than 0.5ℓh

zp hdb τi-perm-SF

= length of the cargo hold between mid-depth of the corrugated bulkhead(s), in m = height of longitudinal bulkhead, in m, defined as the distance from inner bottom to the deck at the top of the bulkhead, as shown in Figure 3

= vertical distance from the lower edge of plate i to the base line, in m, but not less than hdb = height of double bottom, in m, as shown in Figure 3 2

= permissible hull girder shear stress, in N/mm , for plate i

τ

i-perm-SF

= 110/k.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 106

Part 5 Chapter 1 Section 7

2

τi-perm

Part 5 Chapter 1 Section 7 Figure 3 Shear force correction for longitudinal bulkheads 5.1.3 Shear force correction The shear force correction, δQ3, in kN, shall be obtained from the following formula:

where:

Fdb

= maximum resulting force on the double bottom in a cargo hold, in kN, as defined in [5.1.4]

K3

= correction factor, shall be equal to:

The shear force correction factor, K3, may be based on a direct strength analysis. Guidance note: A midship FE cargo hold model applying a static condition with MH in way of mid-hold only on TSC may be used for obtaining r and CT. r should be obtained by taking the ratio in shear force between the side shell and the longitudinal bulkhead in way of the transverse bulkhead. CT should be obtained by taking the ratio in shear force between the longitudinal girders in way of lower stools and total shear force acting on the double bottom. f

3

should be obtained from a numerical shear flow calculation taken as the fraction of the hull girder shear force carried by the

longitudinal bulkhead, including the outboard girder under the inner bottom. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 107

CT lh l tk

= fraction of the centre hold load going through longitudinal girders directly to the transverse bulkhead found by a direct calculation. A value of nL/(nL+nB) may otherwise be used = as given in [5.1.2] = length between transverse bulkheads in wing space, between transverse bulkheads in wing space aligned with cargo hold transverse bulkheads, in m

s nL nB

= distance between floors in the cargo hold, in m

r

= ratio of the part load carried by the partial transverse bulkheads, if any, and floors from longitudinal bulkhead to the side:

b AT-gr

= mean span of transverses in the wing space, including brackets, in m

A1-gr, A2-gr f3

= gross areas, as defined in Table 1, in m

n nS

= number of floors in the wing space

R

= total efficiency of the transverse primary supporting members in the side tank in cm

AQ-gr

= gross shear area, in cm , of a transverse primary supporting member in the side tank, taken as the sum of the gross shear areas of floor, cross tie(s) and deck transverse web. The gross shear area shall be calculated at the mid span of the members

Ipsm-gr

= gross moment of inertia for transverse primary supporting members, in cm , in the side tank, taken as the sum of the moments of inertia of floor, cross tie(s) and deck transverse web. The gross moment of inertia shall be calculated at the mid span of the member including an attached plate width equal to the primary supporting member spacing.

= number of continuous longitudinal girders in the cargo hold = number of floors in the cargo hold

2

= gross shear area of the partial transverse bulkhead, in the wing space, in cm , taken as the smallest area in a vertical section 2

= shear force distribution factor, as defined in Table 1 or based on a numerical shear flow calculation taken as the fraction of the hull girder shear force carried by the longitudinal bulkhead, including the outboard girder under the inner bottom = number of partial transverse bulkheads in the wing space 2

2

4

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 108

Part 5 Chapter 1 Section 7

where:

Hull configuration

where:

A1-gr, A2-gr

Part 5 Chapter 1 Section 7

Table 1 Shear force distribution factor for ore carrier f3 factor

= net projected area onto the vertical plane based on gross thickness, tgr, of the side shell or the longitudinal bulkhead respectively, at one side of the section under consideration. The area A1-gr includes the gross plating area of the side shell, including the bilge. The area A2-gr includes the gross plating area of the longitudinal bulkhead, including the outboard girder under the inner bottom.

5.1.4 Maximum resulting force on double bottom The maximum vertical resulting force on the double bottom in a cargo hold, Fdb, in kN, shall be the greater of: — max positive net vertical force: — max negative vertical force:

where:

b2

= breadth of cargo hold in way of inner bottom or in way of hopper tank top, if fitted, at mid length, in m

lh Tmean

= as given in [5.1.2] = draught at the mid-length of the hold for the loading condition considered given in Table 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 109

Structural configuration

for seagoing operation for harbour/sheltered water operation 1)

Positive/negative force, Fdb

Tmean

1)

OC(H) ships

OC(M) ships

In general

max positive net vertical force, Fdb+

TSC

TS,MIN,ALT,SEA

TSC

max negative net vertical force, Fdb-

THB

TS,MAX,ALT,SEA

THB

max positive net vertical force, Fdb+

TS,MIN,FULL,HAR

max negative net vertical force, Fdb-

TS,MAX,EMPTY,HAR

NA

For OC(M) and OC(H) ships Tmean shall be based on the knuckle points of the hold mass curves for single hold loading, see Pt.6 Ch.1 Sec.5 [5.2] for hold mass curves and Pt.6 Ch.1 Sec.5 [1.5.1] for symbol definitions.

5.1.5 Design criteria for seagoing operation The positive and negative permissible vertical still water shear force, in kN, for seagoing operation shall comply with the following criteria:

where:

QR

= total vertical hull girder shear capacity, in kN, as defined in [5.1.2], applying shear force correction in accordance with [5.1.3] in seagoing operation.

The shear force Qwv used above shall have the same sign as the considered shear force Qsw. 5.1.6 Design criteria for harbour/sheltered water operation The positive and negative permissible vertical still water shear force, in kN, for harbour/sheltered water operation shall comply with the following criteria:

The shear force Qwv used above shall have the same sign as the considered shear force Qsw-p.

5.2 Hull girder yield check 5.2.1 General Ore carriers shall be considered as ships without large deck openings. The requirements given in Pt.3 Ch.5 Sec.3 [3] are therefore not mandatory in this regard.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 110

Part 5 Chapter 1 Section 7

Table 2 Tmean values depending on allowable loading defined by the hold mass curves

5.2.3 Definition of hull girder shear stresses induced by vertical still water shear force for seagoing operation 2 The shear stresses, in N/mm , induced by vertical still water shear force for seagoing operation at the transverse section being considered, are obtained from the following formulae:

where: -1

qvi-n50 ti-n50

= unit shear flow, in mm , for the plate i based on ti-n50, as defined in Pt.3 Ch.5 Sec.3 = net thickness of plate i, in mm. For longitudinal bulkheads within the cargo hold region, ti-n50 shall be equal to tsfi-n50.

For longitudinal bulkhead the net thickness of the plating above the inner bottom, tsfi-n50 for plate i, in mm, is given by:

where:

tΔi

= thickness deduction for plate i, in mm obtained in accordance with [5.1.2], applying shear force correction in accordance with [5.1.3] for seagoing operation.

5.2.4 Definition of hull girder shear stress induced by vertical wave shear force 2 The shear stress, in N/mm , induced by vertical wave shear force for seagoing operation for a dynamic load case at the transverse section being considered, is obtained from the following formula:

where:

qvi-n50 ti-n50

= as given in [5.2.3] = as given in [5.2.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 111

Part 5 Chapter 1 Section 7

5.2.2 Hull girder shear stresses The hull girder shear stress requirements given in Pt.3 Ch.5 Sec.3 [2.2] shall be complied with, applying shear stresses induced by vertical shear forces in accordance with [5.2.3] and [5.2.4].

6.1 Minimum thickness 6.1.1 Minimum thickness in fore peak The minimum net thickness, in mm, of decks and perforated flats acting as transverse strength members shall not be less than:

t = 0.014b 6.1.2 Minimum thickness in machinery space The minimum net thickness, in mm, of platform decks and strength deck acting as transverse strength members shall not be less than:

t = 0.014b

6.2 Plating 6.2.1 Plating subject to lateral pressure The requirements given in Pt.3 Ch.6 Sec.4 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1].

6.3 Stiffeners 6.3.1 Stiffeners subject to lateral pressure The requirements given in Pt.3 Ch.6 Sec.5 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1]. 6.3.2 Minimum moment of inertia of stiffeners in fore peak For stiffened plate panels mentioned in [6.1.1] with longitudinal stiffening orientation, the net moment of 4 inertia, in cm , about the neutral axis parallel to the effective attached plate of stiffener shall not be less than:

I = 19l4 6.3.3 Minimum moment of inertia of stiffeners in machinery space For stiffened plate panels mentioned in [6.1.2], with longitudinal stiffening orientation, the net moment of 4 inertia, in cm , about the neutral axis parallel to the effective attached plate of stiffener shall not be less than:

I = 19l4

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 112

Part 5 Chapter 1 Section 7

6 Hull local scantling

6.4.1 General For primary supporting members not assessed in accordance with [7.1], the requirements given in Pt.3 Ch.6 Sec.6 [2] shall be complied with, applying the loading conditions for PSM given in [4.2], with the additional design load sets given in Sec.2 [5.1]. 6.4.2 Primary supporting members in fore peak Scantlings of primary supporting members being part of a complex 3-dimensional structural system, such as bottom girders, floors, side girders, side stringers, and deck girders, shall be based on an advanced calculation method in accordance with Pt.3 Ch.6 Sec.6 [2.2]. 6.4.3 Primary supporting members in machinery space Scantlings of primary supporting members being part of a complex 3-dimensional structural system, such as side girders, side stringers, and deck girders, shall be based on an advanced calculation method in accordance with Pt.3 Ch.6 Sec.6 [2.2].

6.5 Intersection of stiffeners and primary supporting members 6.5.1 Connection of stiffeners to primary supporting members The requirements for connection of stiffeners to primary supporting members shall comply with Pt.3 Ch.6 Sec.7 [1], including the internal pressure due to dry bulk cargo given in Sec.2 [3].

7 Finite element analysis 7.1 Cargo hold analysis 7.1.1 General Cargo hold analysis shall be carried out in accordance with Pt.3 Ch.7 Sec.1 and Pt.3 Ch.7 Sec.3 using detailed requirements given in the following sub-sections. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0127 Finite element analysis. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: Ore carriers with L ≥ 150 m will be assigned an OC notation with additional requirements for cargo hold analysis given in Pt.6 Ch.1 Sec.5 [7.1] and requirements for local structural strength analysis given in Pt.6 Ch.1 Sec.5 [7.2]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.2 Application Cargo hold analysis of midship region is mandatory irrespective of the ship’s length. 7.1.3 FE load combinations The load combinations to be applied to the FE model shall be based on the required design load combinations for direct strength analysis of PSM given in [4.2]. 7.1.4 Internal loads Bulk pressures and shear loads shall be applied to the FE model in accordance with Sec.2 [3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 113

Part 5 Chapter 1 Section 7

6.4 Primary supporting members

8.1 Hull girder buckling The hull girder buckling requirements given in Pt.3 Ch.8 Sec.3 shall be complied with, applying the additional design load sets given in Sec.2 [5.1]. For hull girder buckling assessment of design load sets representing design load scenario 2, hull girder shear stress components in accordance with [5.2.3] and [5.2.4] shall be applied.

9 Fatigue 9.1 General 9.1.1 Fatigue assessment shall be carried out for ships having a length L of not less than 90 m in accordance with Pt.3 Ch.9, using detailed requirements in the following sub-sections. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0129 Fatigue assessment of ship structure. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9.2 Prescriptive fatigue strength assessment 9.2.1 General Within the cargo region, the fatigue life of longitudinal end connections in way of web frames and transverse bulkheads shall be assessed in accordance with DNVGL-CG-0129 Sec.4.

10 Cargo hatch covers and hatch coamings 10.1 General Cargo hatch covers and coamings shall comply with the requirements given in CSR Pt.2 Ch.1 Sec.5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 114

Part 5 Chapter 1 Section 7

8 Buckling

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction These rules apply to ships specialised for the carriage of a single type of dry bulk cargo.

1.2 Scope This section describes requirements for arrangement and hull strength, including: — — — — — — — —

general arrangement design, see [2] structural design principles, see [3] loads, see [4] hull girder strength, see [5] hull local scantling, see [6] finite element analysis, see [7] buckling, see [8] fatigue, see [9].

1.3 Application 1.3.1 The requirements in this section are applicable to ships intended for the carriage of a single type of dry bulk cargo limited to one of the following: woodchips, cement, fly ash or sugar. 1.3.2 Ships complying with the requirements given in this section will be assigned the ship type class notation X carrier, where X denotes the type of cargo to be carried, e.g. Woodchips, Cement, Fly ash or Sugar.

2 General arrangement design 2.1 Compartment arrangement 2.1.1 Arrangement of cargo hold region The ship shall have a double bottom within the cargo region and a single deck. Hatches to cargo holds shall be arranged as required for access only, and for the closed loading and unloading arrangement. 2.1.2 Loading and unloading arrangement The cargo holds shall be arranged with a closed loading and unloading arrangement. Documentation of the intended loading and unloading system shall be submitted for information.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 115

Part 5 Chapter 1 Section 8

SECTION 8 SHIPS SPECIALISED FOR THE CARRIAGE OF A SINGLE TYPE OF DRY BULK CARGO

3.1 Structural arrangement The requirements given in Sec.2 [2] shall be complied with, as applicable.

4 Loads 4.1 Standard design loading conditions 4.1.1 General The standard design loading conditions given in the following sub-sections shall be considered in addition to the standard loading conditions given in Pt.3 Ch.4 Sec.8 [1]. 4.1.2 Dry bulk cargo loading condition Homogeneous cargo loaded condition shall be included in the loading manual where the cargo density corresponds to all cargo holds, including hatchways, being 100% full at scantling draught. 4.1.3 Guidance for loading/unloading sequences Typical loading/unloading sequences, having unevenly distributed cargo between cargo holds, shall be included in the loading manual in accordance with Pt.6 Ch.1 Sec.4 [10.3].

4.2 Loading conditions for primary supporting members 4.2.1 General The design loading conditions for direct strength analysis of primary supporting members shall envelope all loading conditions included in the loading manual, as required in Pt.3 Ch.4 Sec.8 [2] and [4.1]. Guidance note: The seagoing FE design load combinations given in Pt.6 Ch.1 Sec.4 [4.2.8] for HC(M) ships may be used as guidance for ballast loading conditions and dry bulk cargo loading conditions. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5 Hull girder strength 5.1 Loading manual and loading instrument The ships shall belong to category I. Ships intended for the carriage of homogeneous loads only, may upon request, be considered according to the requirements for ships in category II.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 116

Part 5 Chapter 1 Section 8

3 Structural design principles

6.1 Minimum thickness 6.1.1 Minimum thickness of inner bottom in cargo holds The minimum net thickness, in mm, of inner bottom plating in cargo holds shall be in accordance with Pt.3 Ch.6 Sec.3 [1.1.1] with:

a = 7.0 b = 0.05

6.2 Plating 6.2.1 Plating subject to lateral pressure The requirements given in Pt.3 Ch.6 Sec.4 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1].

6.3 Stiffeners 6.3.1 Stiffeners subject to lateral pressure The requirements given in Pt.3 Ch.6 Sec.5 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1].

6.4 Primary supporting members 6.4.1 General For primary supporting members not assessed in accordance with [7.1], the requirements given in Pt.3 Ch.6 Sec.6 [2] shall be complied with, applying the loading conditions for PSM given in [4.2], with the additional design load sets given in Sec.2 [5.1].

6.5 Intersection of stiffeners and primary supporting members 6.5.1 Connection of stiffeners to primary supporting members The requirements for connection of stiffeners to primary supporting members shall comply with Pt.3 Ch.6 Sec.7 [1], including the internal pressure due to dry bulk cargo given in Sec.2 [3].

7 Finite element analysis 7.1 Cargo hold analysis 7.1.1 General Cargo hold analysis shall be carried out in accordance with Pt.3 Ch.7 Sec.1 and Pt.3 Ch.7 Sec.3 using detailed requirements given in the following sub-sections. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0127 Finite element analysis . ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 117

Part 5 Chapter 1 Section 8

6 Hull local scantling

7.1.3 FE load combinations The load combinations to be applied to the FE model shall be based on the required design load combinations for direct strength analysis of PSM given in [4.2]. 7.1.4 Internal loads Bulk pressures and shear loads shall be applied to the FE model in accordance with Sec.2 [3].

8 Buckling 8.1 Hull girder buckling The requirements given in Pt.3 Ch.8 Sec.3 shall be complied with, applying the additional design load sets given in Sec.2 [5.1].

9 Fatigue 9.1 General 9.1.1 Fatigue assessment shall be carried out for ships having a length L of not less than 90 m, in accordance with Pt.3 Ch.9 using detailed requirements in the following sub-sections. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0129 Fatigue assessment of ship structure. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9.2 Prescriptive fatigue strength assessment 9.2.1 General Within the cargo region, the fatigue life of longitudinal end connections in way of web frames and transverse bulkheads shall be assessed in accordance with DNVGL-CG-0129 Sec.4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 118

Part 5 Chapter 1 Section 8

7.1.2 Application Cargo hold analysis of midship region is mandatory irrespective of the ship’s length.

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2].

1 Introduction 1.1 Introduction These rules apply to ships primarily intended for the carriage of solid bulk cargoes operating on the Great Lakes and St Lawrence river.

1.2 Scope This section describes requirements for arrangement, hull strength, hull equipment and stability, including: — — — — — — — — — — — —

general arrangement design, see [2] structural design principles, see [3] loads, see [4] hull girder strength, see [5] hull local scantling, see [6] finite element analysis, see [7] buckling, see [8] fatigue, see [9] special requirements, see [10] hull equipment, supporting structures and appendages, see [11] openings and closing appliances, see [12] stability, see [13].

1.3 Application 1.3.1 These rules are applicable to ships primarily intended to carry dry cargoes in bulk designed to operate within the limits of the Great Lakes and the St. Lawrence River to the seaward limits defined by Anticosti Island, and having single deck with a double side skin construction and double bottom construction throughout the cargo hold region. 1.3.2 Ships complying with the requirements given in this section will be assigned the ship type class notation Great lakes bulk carrier.

2 General arrangement design 2.1 Subdivision arrangement 2.1.1 Watertight bulkhead arrangement The requirements given in Pt.3 Ch.2 Sec.2 shall be complied with, with the following exemption: Pt.3 Ch.2 Sec.2 [1.1.4] is not mandatory.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 119

Part 5 Chapter 1 Section 9

SECTION 9 GREAT LAKES BULK CARRIERS

3 Structural design principles 3.1 Corrosion additions The corrosion addition for one side of structural members within a ballast water tank shall be taken as for fresh water, fuel oil and lube oil tank given in Pt.3 Ch.3 Sec.3 Table 1.

3.2 Structural arrangement The requirements given in Sec.2 [2] shall be complied with, where applicable.

4 Loads 4.1 General 4.1.1 Service area restriction The loads for strength assessment given in Pt.3 Ch.4 and Sec.2 [3] shall be established applying the reduction factors given by the service area notation RE. The loads for fatigue assessment given in Pt.3 Ch.4 is not mandatory.

4.2 Standard design loading conditions 4.2.1 General The standard design loading conditions given in [4.2.2] shall be considered in addition to the standard loading conditions given in Pt.3 Ch.4 Sec.8 [1]. 4.2.2 Dry bulk cargo loading condition Homogeneous cargo loaded condition shall be included in the loading manual where the cargo density corresponds to all cargo holds, including hatchways, being 100% full at scantling draught.

4.3 Loading conditions for primary supporting members The loading conditions for direct strength analysis of primary supporting members shall envelope all loading conditions included in the loading manual, as required in Pt.3 Ch.4 Sec.8 [2] and [4.2], with loads in accordance with [4.1.1]. Guidance note: The seagoing FE design load combinations given in Pt.6 Ch.1 Sec.4 [4.2.8] for HC(M) ships may be used as guidance for ballast loading conditions and dry bulk cargo loading conditions. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 120

Part 5 Chapter 1 Section 9

2.1.2 Collision bulkhead The requirements for collision bulkhead given in Pt.3 Ch.2 Sec.2 [4] shall be complied with, applying a minimum distance of 0.04 LLL aft of the reference point.

5.1 Vertical hull girder shear strength 5.1.1 Shear force correction Hull girder shear strength assessment, including shear force correction, shall be carried out in accordance with Sec.5 [5.2].

5.2 Hull girder yield check 5.2.1 Hull girder stress components The additional hull girder strength requirements for ships with large deck openings given in Pt.3 Ch.5 Sec.3 [3] are not mandatory.

5.3 Hull girder ultimate strength check The hull girder ultimate strength requirements given in Pt.3 Ch.5 Sec.4 are not mandatory.

6 Hull local scantling 6.1 Plating 6.1.1 Plating subject to lateral pressure The requirements given in Pt.3 Ch.6 Sec.4 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1], with loads in accordance with [4.1.1].

6.2 Stiffeners 6.2.1 Stiffeners subject to lateral pressure The requirements given in Pt.3 Ch.6 Sec.5 [1] shall be complied with, applying the additional design load sets given in Sec.2 [5.1], with loads in accordance with [4.1.1].

6.3 Primary supporting members For primary supporting members not assessed in accordance with [7.1], the requirements given in Pt.3 Ch.6 Sec.6 [2] shall be complied with, applying the loading conditions for PSM given in [4.2], with the additional design load sets given in Sec.2 [5.1] and loads in accordance with [4.1.1].

6.4 Intersection of stiffeners and primary supporting members 6.4.1 Connection of stiffeners to primary supporting members The requirements for connection of stiffeners to primary supporting members shall comply with Pt.3 Ch.6 Sec.7 [1], including the internal pressure due to dry bulk cargo given in Sec.2 [3], with loads in accordance with [4.1.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 121

Part 5 Chapter 1 Section 9

5 Hull girder strength

7.1 Cargo hold analysis 7.1.1 General Cargo hold analysis shall be carried out in accordance with Pt.3 Ch.7 Sec.1 and Pt.3 Ch.7 Sec.3 using detailed requirements given in the following sub-sections. Guidance note: Calculation methods acceptable to the Society are further outlined in DNVGL-CG-0127 Finite element analysis. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.2 Application Cargo hold analysis of midship region is mandatory irrespectively of ship’s length. 7.1.3 FE load combinations The load combinations to be applied to the FE model shall be based on the required design load combinations for direct strength analysis of PSM given in [4.3]. 7.1.4 Internal loads Bulk pressures and shear loads shall be applied to the FE model in accordance with Sec.2 [3], with loads in accordance with[4.1.1].

8 Buckling 8.1 Hull girder buckling The requirements given in Pt.3 Ch.8 Sec.3 shall be complied with, applying the additional design load sets given in Sec.2 [5.1], with loads in accordance with [4.1.1].

9 Fatigue 9.1 General The fatigue requirements given in Pt.3 Ch.9 are not mandatory.

10 Special requirements 10.1 Bow impact Requirements for strengthening for bow impact loads as given in Pt.3 Ch.10 Sec.1 are not mandatory. Guidance note: Operational experience indicates that navigation in the seaway locks and in light ice may cause contact damages to plating and framing in fore and aft shoulder areas. In order to reduce the risk of local structural deformations, it is advised that this is considered in the design. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 122

Part 5 Chapter 1 Section 9

7 Finite element analysis

Requirements for strengthening for bottom slamming loads as given in Pt.3 Ch.10 Sec.2 are not mandatory.

10.3 Stern slamming Requirements for strengthening for stern slamming loads as given in Pt.3 Ch.10 Sec.3 are not mandatory.

11 Hull equipment, supporting structures and appendages 11.1 Anchoring and mooring equipment 11.1.1 Equipment number The equipment number, EN’, is given by the formula: EN’ = 0.3 LBD + α + b where:

a

st

= addition for the 1

tier of superstructure and deck houses st

17.6% of volume of 1

b

tier (length × breadth × height)

= addition for the 2nd tier of deckhouses and other erections nd

13.2% of the volume of the 2

tier (length × breadth × height).

11.1.2 Anchors Two bower anchors in accordance with Pt.3 Ch.11 Sec.1, applying equipment number given in [11.1.1], shall be provided. A stern anchor shall be fitted as required by the St. Lawrence Seaways Authority. 11.1.3 Anchor chain cables A stud-link chain cable of total length 330 m in accordance with Pt.3 Ch.11 Sec.1 shall be provided onboard.

11.2 Supporting structure for deck equipment and fittings 11.2.1 Shipboard fittings and supporting hull structures associated with towing and mooring Requirements for supporting structure of deck fittings equipment and fittings as given in Pt.3 Ch.11 Sec.2 are not mandatory.

11.3 Bulwark and protection of crew Requirements for supporting structure of deck fittings equipment and fittings as given in Pt.3 Ch.11 Sec.2 [5] are not mandatory. 11.3.1 Minimum height The minimum height of bulwarks or guard rails given in Pt.3 Ch.11 Sec.3 [1.2]may be disregarded and shall be at least 900 mm in height. 11.3.2 Protection of the crew The requirements for guard rails given in Pt.3 Ch.11 Sec.3 [3.1] are not mandatory.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 123

Part 5 Chapter 1 Section 9

10.2 Bottom slamming

— three courses shall be fitted as a minimum. The spacing between lowest course and ship's deck shall not exceed 230 mm. The spacing between courses shall not exceed 380 mm. — if the sheer strake projects at least 200 mm above the deck, two courses shall be fitted as a minimum. The spacing between the lower course and the sheer strake or the upper course shall not exceed 380 mm. 11.3.3 Gangways, walkways and passageways The requirements for gangways, walkways and passageways given in Pt.3 Ch.11 Sec.3 [3.2] are not mandatory. The ship shall have lifelines, gangways or under deck passages for the protection of the crew while passing to and from their accommodation spaces, the machinery space and all other spaces used in the normal operation of the vessel. Whenever bulkhead openings are closed, other access shall be provided for the crew to reach accommodation spaces or machinery or other working spaces in enclosed superstructures that are bridges or poops. If an exposed part of a freeboard deck is in way of a trunk, guardrails shall be fitted for one-half the length of the exposed part.

12 Openings and closing appliances 12.1 General Openings and closing appliances shall comply with the requirements given in Pt.3 Ch.12, applying the Canadian Load Line Regulations instead of the International Load Line Regulations.

12.2 Small hatchways and weathertight doors 12.2.1 Height of hatch coamings The height above deck of hatchway coamings shall be at least 460 mm in position 1 and at least 300 mm in position 2. The requirements to hatch coaming heights given in Pt.3 Ch.12 Sec.2 [2.3] are not mandatory. 12.2.2 Weathertight doors - sill heights Doors in position 1 or position 2 shall have a sill height, measured from the deck, of at least 300 mm. The requirements to sill heights given in Pt.3 Ch.12 Sec.2 [4] are not mandatory.

12.3 Cargo hatch covers/coamings and closing arrangements 12.3.1 Heigh of hatch coamings The height above deck of hatchway coamings shall be at least 460 mm in position 1 and at least 300 mm in position 2. The requirements to hatch coaming heights given in Pt.3 Ch.12 Sec.4 [5] are not mandatory. 12.3.2 Hatch covers The requirements for hatch covers given in Pt.3 Ch.12 Sec.4 shall be complied with, applying the load model and strength requirements given in the Canadian Load Line Regulations instead of the International Load Line Regulations. The corrosion additions given in Pt.3 Ch.12 Sec.4 Table 1 are not mandatory.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 124

Part 5 Chapter 1 Section 9

Guard rails shall be fitted, complying with minimum one of the following:

12.4.1 Lower edge of side doors, stern and bow doors/ramps The lower edge of side door and other similar openings shall not be below a line drawn parallel to the freeboard deck at side that has the upper edge of the uppermost load line at its lowest point.

12.5 Tank access, ullage and ventilation openings 12.5.1 Air pipes Air pipes shall have a coaming height of at least 760 mm on the freeboard deck, 600 mm on raised quarter decks and 300 mm other superstructure decks. 12.5.2 Ventilators Ventilator coamings shall be at least 760 mm above deck in position 1 and at least 600 mm above deck in position 2. Ventilator openings shall have permanently attached weather tight means of closing. The requirement for weather tight closing appliances is not applicable for ventilators in position 1 with coamings that extend 3.8 m or more above the deck or to ventilators in position 2 with coamings that extend 1.8 m or more above deck.

12.6 Machinery space openings The lower edge of any access opening in the casing shall be at least 300 mm above the deck. If the opening is a funnel or machinery space ventilator that needs to be kept open for the essential operation of the vessel, then the coaming height shall be at least 3.8 m in position 1 and 1.8 m in position 2.

12.7 Scuppers, inlets and discharges 1)

Every discharge pipe passing through the shell from spaces below the freeboard deck shall comply with either a) or b) below: a)

have an automatic non-return valve fitted at the shell with a positive means of closing that is operable i) ii)

b) 2)

from above the freeboard deck, or from a readily accessible location if the discharge originates in a space that is crewed or equipped with a means of continuously monitoring the level of bilge water

have two automatic non-return valves, one of which is fitted at the shell and one inboard that is accessible for examination when the vessel is in service.

Every discharge pipe that passes through the shell from within an enclosed superstructure, or from within a deckhouse that protects openings to below the freeboard deck, shall comply with either a) or b) below: a) b)

meet the requirements set out in paragraph 1) a) or b) have an automatic non-return valve fitted at the shell, if the discharge originates in a space that is regularly visited by the crew.

3)

Every scupper, drain or discharge pipe that passes through the shell above the summer fresh water load line at a distance that is less than the greater of 5% of the breadth and 600 mm, shall have an automatic non-return valve fitted at the shell.

4)

Item 3) does not apply in respect of a scupper, drain or discharge pipe that originates above the freeboard deck, if the part of the pipe that is between the shell and the freeboard deck has substantial thickness.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 125

Part 5 Chapter 1 Section 9

12.4 Side, stern and bow doors/ramps

In crewed machinery spaces, every main and auxiliary sea inlet and discharge necessary for the operation of machinery shall have a valve with a positive means of closing that can be controlled locally.

6)

The valves required by this section to have positive means of closing shall have indicators at the operating position to show whether the valve is open or closed.

12.8 Freeing ports The freeing port area shall be calculated as described in Pt.3 Ch.12 Sec.10 [2.1] with due attention to adjustments due to the height of the bulwark as given below: 2

The freeing port area shall be increased by 0.04 m per metre of length of the well, for each metre that the height of the bulwark exceeds: — 600 mm, in the case of vessels that are 73 m in length or less — 1200 mm, in the case of vessels that are 146 m in length or more, and — in the case of vessels that are of intermediate length, the height obtained by linear interpolation between the heights set out in points above.

13 Stability 13.1 General The requirements for stability given in Pt.3 Ch.15 shall be complied with, applying Canadian flag stability requirements.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 126

Part 5 Chapter 1 Section 9

5)

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Amendments January 2016 • Sec.6 Bulk carriers — [2.1.2]: Clarification on how to handle CSR vessels has been inserted. — [2.1.3]: Applicable regulations for access to tanks and compartments (IACS UI 191 and SOLAS Reg. II-1/3.6) has been inserted.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.1. Edition July 2017, amended January 2018 Bulk carriers and dry cargo ships

DNV GL AS

Page 127

Part 5 Chapter 1 Changes – historic

CHANGES – HISTORIC

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition January 2018

Part 5 Ship types Chapter 2 Container ships

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the July 2016 edition of DNVGL-RU-SHIP Pt.5 Ch.2. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018. Topic Fatigue loads

Reference Sec.3 [2.2.3]

Description Adjusted factors related to operational profile "fR" for container ships to ensure consitency with changes done in Pt.3 Ch.4 and Pt.3 Ch.9.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 3

Part 5 Chapter 2 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................... 8 1 Introduction.........................................................................................8 1.1 Introduction..................................................................................... 8 1.2 Scope..............................................................................................8 1.3 Application....................................................................................... 8 1.4 Class notations.................................................................................8 1.5 Definitions....................................................................................... 9 2 Documentation and certification........................................................ 10 2.1 Documentation requirements............................................................10 2.2 Certification requirements................................................................ 11 Section 2 Structural design principles...................................................................12 1 General.............................................................................................. 12 Section 3 Loads..................................................................................................... 13 1 General.............................................................................................. 13 2 Hull girder loads................................................................................ 13 2.1 Still water hull girder loads.............................................................. 13 2.2 Dynamic hull girder loads................................................................ 13 2.3 Permissible still waterloads for harbor/sheltered water operations..........18 3 Loading condition.............................................................................. 19 3.1 Standard design loading conditions................................................... 19 Section 4 Hull girder strength...............................................................................20 1 General.............................................................................................. 20 2 Strength assessment......................................................................... 20 2.1 Corrosion margin and net-scantlings................................................. 20 2.2 Load cases..................................................................................... 21 2.3 Hull girder stress............................................................................ 22 2.4 Yield strength assessment............................................................... 23 2.5 Buckling assessment....................................................................... 24 2.6 Ultimate hull girder strength assessment........................................... 24 Section 5 Hull local scantlings.............................................................................. 27 1 General.............................................................................................. 27 2 Primary supporting members............................................................ 27

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 4

Part 5 Chapter 2 Contents

CONTENTS

3 Special requirements......................................................................... 28 3.1 Wave breakers................................................................................28 Section 6 Finite element analysis..........................................................................29 1 General.............................................................................................. 29 2 Cargo hold finite element analysis.....................................................29 2.1 Application..................................................................................... 29 2.2 Scope............................................................................................ 29 2.3 Design load combinations................................................................ 29 2.4 Acceptance criteria..........................................................................32 3 Fuel oil deep tank finite element analysis......................................... 33 3.1 Application..................................................................................... 33 3.2 Scope............................................................................................ 33 3.3 Modelling principles......................................................................... 33 3.4 Design load combinations................................................................ 33 3.5 Acceptance criteria..........................................................................36 Section 7 Fatigue.................................................................................................. 37 1 General.............................................................................................. 37 1.1 Scope............................................................................................ 37 2 Prescriptive fatigue strength calculations..........................................37 2.1 Longitudinal stiffener end connections............................................... 37 2.2 Welded details in the upper part of the hull girder...............................37 2.3 Knuckles and discontinuities in the upper part of the hull girder............ 38 Section 8 Container securing arrangement........................................................... 39 1 General.............................................................................................. 39 1.1 Container securing arrangements......................................................39 1.2 Container securing structures........................................................... 39 2 Stowage of containers on deck..........................................................40 2.1 General..........................................................................................40 2.2 Stowage on deck with neither lashing nor lateral rigid support.............. 40 2.3 Stowage on deck with lashing but without lateral rigid support..............41 2.4 Stowage on deck with lateral rigid support.........................................42 3 Stowage of containers below deck.................................................... 43 3.1 Stowage below deck in cell guides.................................................... 43 4 Loads acting on containers................................................................ 44 4.1 General..........................................................................................44 4.2 Wind loads..................................................................................... 45

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 5

Part 5 Chapter 2 Contents

2.1 Prescriptive requirements.................................................................27

4.4 Longitudinal forces.......................................................................... 47 4.5 Vertical forces................................................................................ 47 5 Design load combinations for container securing arrangements........ 48 5.1 Design load combinations................................................................ 48 6 Design load combinations for container securing structures.............. 49 6.1 General..........................................................................................49 6.2 Design load combinations for lashing bridge....................................... 49 6.3 Design load combinations for cell guide............................................. 50 6.4 Design load combinations for container stanchions.............................. 50 7 Acceptance criteria............................................................................ 51 7.1 Acceptance criteria for container securing arrangements...................... 51 7.2 Permissible forces for container securing structures.............................51 8 Strength evaluation........................................................................... 52 8.1 Strength evaluation of container securing arrangements...................... 52 8.2 Strength evaluation of container securing structures........................... 52 9 Lashing computer system.................................................................. 53 9.1 Application..................................................................................... 53 9.2 Definition....................................................................................... 53 9.3 Approval and certification process..................................................... 53 9.4 Hardware approval.......................................................................... 53 9.5 Software approval........................................................................... 53 9.6 Certification....................................................................................55 Section 9 Hull support structures for container support fittings and container securing structures............................................................................................... 56 1 General.............................................................................................. 56 1.1 Objective....................................................................................... 56 2 General requirements........................................................................ 56 2.1 Strength evaluation.........................................................................56 2.2 Structure arrangement.................................................................... 56 3 Design loads...................................................................................... 56 3.1 General..........................................................................................56 3.2 Hull support structures for container support fittings........................... 56 3.3 Hull support structures for container securing structures...................... 57 4 Strength evaluation........................................................................... 57 4.1 General..........................................................................................57 Section 10 Application of thick steel plates and additional requirements for steel strength group VL47.................................................................................... 58

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 6

Part 5 Chapter 2 Contents

4.3 Transverse forces............................................................................ 46

1.1 Application..................................................................................... 58 2 Application of thick steel plates........................................................ 58 2.1 General..........................................................................................58 2.2 Brittle crack arrest design................................................................59 2.3 Non-destructive testing during construction........................................62 2.4 Measures for thick steel plates......................................................... 62 3 Additional requirements for steel strength group VL47..................... 63 3.1 General..........................................................................................63 3.2 Fatigue.......................................................................................... 64 3.3 Non-destructive testing....................................................................66 4 Enhanced non destructive testing of welds....................................... 66 4.1 Application..................................................................................... 66 4.2 Magnetic particle testing procedure................................................... 66 4.3 Ultrasonic testing procedure............................................................. 67 Changes – historic................................................................................................ 71

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 7

Part 5 Chapter 2 Contents

1 General.............................................................................................. 58

1 Introduction 1.1 Introduction This chapter applies to ships intended for the carriage of containers.

1.2 Scope The rules in this chapter include requirements regarding hull strength and the relevant procedural requirements. The requirements shall be regarded as supplementary to those given in rules for the assignment of main class.

1.3 Application These rules shall be applied to sea-going ships primarily intended for the carriage of containers having the following characteristics: — equipped with fixed stowage appliance in the form of cell guides at the bulkheads — fixed container foundations on the inner bottom — fixed appliances for stowage and lashing on the upper deck and/or hatch covers. The transport of other cargo, i.e. break bulk on the inner bottom, may be accepted on a case by case basis. The transport of dry cargo in bulk is not permitted.

1.4 Class notations 1.4.1 Ship type notation Ships built in compliance with the requirements as specified in Table 1 will be assigned the ship type notation as follows: Table 1 Ship type notation for container ships Class notation

Description

Design requirements, rule references

Container ship

Ship primarily intended for the carriage of containers

1.4.2 Additional notations The following additional notations, as specified in Table 2, are typically applied to ships with ship type notation Container ship and partly true for ships with the additional notation Container. Table 2 Additional notations Class notation

Description

Application

Rule reference

RSD

Requirements for global finite element strength analysis.

Ships with the notation Container ship

Pt.6 Ch.1 Sec.8

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 8

Part 5 Chapter 2 Section 1

SECTION 1 GENERAL

Description

Application

Rule reference

WIV

Fatigue and ultimate hull girder verified under explicit consideration of wave induced vibrations (whipping and springing).

Ships with the notation Container ship

Pt.6 Ch.1 Sec.11

RCP

Refrigerated container stowage positions.

Ships with the notations Container ship or Container

Pt.6 Ch.4 Sec.9

RSCS

Route specific container stowage for ships intended to carry containers on a specified sea route.

Ships with the notations Container ship or Container

Pt.6 Ch.4 Sec.11

Hatchcoverless

For hatchcoverless container ships equipped with the appropriate facilities.

Ships with the notation Container ship

Pt.6 Ch.5 Sec.2

DG

Arrangement for carriage of dangerous goods All ships in packed form.

Pt.6 Ch.5 Sec.10

SAFELASH

Increased safety level for crew members and stevedores engaged in the handling and securing of containers.

Ships with the notations Container ship or Container

Pt.6 Ch.8 Sec.3

Designed and arranged for roll-on and roll-of cargo handling and transportation of rolling vehicles.

Multi-purpose dry cargo ship with additional purpose of loading/ unloading roll-on and rolloff cargo in dedicated RO/ RO space.

Pt.6 Ch.5 Sec.19

RO/RO

Part 5 Chapter 2 Section 1

Class notation

For a full definition of all class additional notations, see Pt.1 Ch.2 Sec.1.

1.5 Definitions For definitions not defined in this section, see Pt.3 Ch.1 Sec.4 [3]. Definitions for container ships are given in Table 3. Table 3 Definitions of terms Terms

Definition

container

freight container according ISO Standard, or other specially approved container

container stack

containers which are stacked vertically and secured horizontally by stackers, lashings, etc.

container block

a number of stacks interconnected and secured horizontally by bridges stackers or double stacking cones

container securing devices

container securing equipment and container support fittings

container securing equipment

loose container securing devices for securing and supporting of containers (e.g. twistlocks, midlocks, stackers, turnbuckles, lashing rods)

container support fittings

fixed container securing devices for securing and supporting of containers welded to tank tops, decks, bulkheads or hatch covers (e.g. raised ISO-foundations, flush/weld in foundations, lashing eye plates, D-rings, guide fittings)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 9

Definition

container wall ends

the transverse end of the container constructed as a closed wall

container door ends

the transverse end of the container constructed with doors for access

lateral rigid supports

members serving securing arrangements so that the stiffness of the containers does not influence on support forces and internal forces in containers (e.g. cross ties, cell guides and buttress)

container securing structures

structures taking container support forces not being an integral part of the hull structures (e.g. cell guides, lashing bridges and stanchions)

cell guides

an arrangement in holds or on deck of fixed vertical guide rails for support of containers

self-supporting cell guide

cell guides which are not attached to transverse bulkheads

lashing bridges

framed structures on deck where lashings are secured

stanchion

pillar type structures on deck for support of outermost container stack

container free end

free end of 20 ft. containers stowed in 40 ft. cell guides

safe working load, SWL

the safe working load certified for container securing devices, based on testing or calculations

minimum breaking load

the tested minimum breaking strength of a container securing device

lashing computer system

computer based system for calculation and control of container securing arrangements for compliance with applicable strength requirements

2 Documentation and certification 2.1 Documentation requirements 2.1.1 Container ships Documentation shall be submitted as required by Table 4. The documentation will be reviewed by the Society as a part of the class contract. This table is partly applicable for ships with the additional notation Container. Table 4 Documentation requirements Object

Documentation type

Additional description

Info

Cell guides, including: — nominal cell guide/container clearance Container stanchions H050 – Structural drawing Cargo securing arrangement

Lashing bridges, including — lashing eye arrangement

AP

— force plan — access plan. Fixed fitting arrangement H050 – Structural drawing

Supporting structures for cell guides, container stanchions, lashing bridges and container fittings.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

AP

Page 10

Part 5 Chapter 2 Section 1

Terms

Documentation type

Additional description

H190 – Container securing arrangement plan

AP

Z030 – Arrangement plan

Container stowage plan Including:

I270 – Test conditions Lashing computer system software

Info

— a software installation.

FI AP

I280 – Reference data

FI

Z161 – Operational manual

FI

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

2.2 Certification requirements 2.2.1 Products shall be certified as required by Table 5. Table 5 Certification requirements Object

Certification standard*

Certificate type

Issued by

Additional description

Container support fittings

PC

Society

DNVGL-CP-0068, Container securing devices

Container securing equipment

PC

Society

DNVGL-CP-0068, Container securing devices

Cell guides

MC

Society

Lashing bridges

MC

Society

Container stanchions

MC

Society

Lashing computer

PC

Society

See Sec.8 [9] for requirements for certification

* Unless otherwise specified the certification standard is the rules. PC = Product certificate, MC = Material certificate

For general certification requirements, see Pt.1 Ch.3 Sec.4. For a definition of the certification types, see Pt.1 Ch.3 Sec.5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 11

Part 5 Chapter 2 Section 1

Object

Part 5 Chapter 2 Section 2

SECTION 2 STRUCTURAL DESIGN PRINCIPLES 1 General The structural design principles shall be according to Pt.3 Ch.3 except those requirements given in this section.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 12

1 General The static and dynamic loads shall be according to Pt.3 Ch.4 except for those requirements given in this section.

2 Hull girder loads 2.1 Still water hull girder loads Guidance note: When determining the required section modulus of the midship section of container ships in the range x/L = 0.3 to x/L = 0.55 it is recommended to use at least the following initial value for the hogging still water bending moment, in kNm: 2

MSW,ini = n1 · cw · L · B(0.123 – 0.015cB) where:

n1 =

factor to take into account the total mass of 20 ft. containers (TEU) the ship can carry, taken as:

with n1 ≤ 1.2

n =

maximum number of 20 ft. containers (TEU) of the mass G, in t, the ship can carry

G =

14 t.

The initial hogging still water bending moment MSW,ini should be graduated regularly to ship's ends. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2 Dynamic hull girder loads 2.2.1 General The vertical wave bending moments and shear forces defined in this section shall be applied in lieu of the vertical wave bending moment and shear forces defined in Pt.3 Ch.4 Sec.4 [3]. 2.2.2 Wave parameter for vertical wave loads The wave parameter is defined as follows: C = 1 − 1.50

for L ≤ Lref

C = 1 − 0.45

for L > Lref

where:

Lref

= reference length, in m, taken as: -1.3

Lref = 315CWL

for the determination of vertical wave bending moments according to [2.2.3]

Lref =

for the determination of vertical wave shear forces according to [2.2.4]

-1.3 330CWL

CWL

= waterplane coefficient at scantling draught, to be taken as:

AW

= waterplane area at scantling draught, in m .

CWL = AW/(LB)

2

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 13

Part 5 Chapter 2 Section 3

SECTION 3 LOADS

Part 5 Chapter 2 Section 3

2.2.3 Vertical wave bending moment The vertical wave bending moments at any longitudinal position, in kNm, shall be taken as:

where:

fR

= factor related to the operational profile, to be taken as:

fp fNL-Hog

= factor given in [3.1.1]

fR = as given in Pt.3 Ch.4 Sec.4 [3.1.1] for strength assessment fR = as given in Pt.3 Ch.9 Sec.4 [4.3] for fatigue assessment = non-linear correction for hogging, to be taken as: for strength assessment, not to be taken greater than 1.1 for fatigue assessment

fNL-Sag

= non-linear correction for sagging, to be taken as: for strength assessment, not to be taken less than 1.0 for fatigue assessment

fBow

= bow flare shape coefficient, to be taken as:

ADK

= projected area in horizontal plane of uppermost deck, in m including the forecastle deck, if any, extending from 0.8Lforward, see Figure 1. Any other structures, e.g. plated bulwark, shall be excluded

AWL zf

= waterplane area, in m , at draught T, extending from 0.8L forward

cM

= distribution factors according to Table 1.

2

2

= vertical distance, in m, from the waterline at draught T to the uppermost deck (or forecastle deck), measured at F.E., see Figure 1. Any other structures, e.g. plated bulwark, shall be excluded

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 14

Part 5 Chapter 2 Section 3 Figure 1 Projected area ADK and vertical distance zf

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 15

Hogging condition

Part 5 Chapter 2 Section 3

Table 1 Distribution factor cM Sagging condition

Range

Value

Range

Value

0 ≤ x/L < 0.1

1.5 x/L

0 ≤ x/L < 0.35

2.86 x/L

0.1 ≤ x/L < 0.35

3.4x/L − 0.19

0.35 ≤ x/L < 0.6

1.0

0.35 ≤ x/L < 0.55

1.0

0.6 ≤ x/L ≤ 1.0

2.5(1 − x/L)

0.55 ≤ x/L < 0.8

2.65 − 3x/L

0.8 ≤ x/L ≤ 1.0

1.25(1 − x/L) Distribution over the ship's length

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 16

Part 5 Chapter 2 Section 3

2.2.4 Vertical wave shear force The vertical wave shear forces at any longitudinal position, in kN, shall be taken as:

where:

fp

= factor given in Pt.3 Ch.4 Sec.4 [3.2].

Table 2 Distribution of vertical wave shear force over the ship length Hogging condition Range

Sagging condition Value

Range

5x/L*

0 ≤ x/L < 0.2

0.2 ≤ x/L < 0.3 (4 − 10x/L) +

0.3 ≤ x/L < 0.4

(4 − 10x/L)+

0.3 ≤ x/L < 0.4

(10x/L − 3)

0.4 ≤ x/L ≤ 0.5

(3 − 10x/L)

0.4 ≤ x/L ≤ 0.5 (10x/L − 5) +

(10x/L − 6)

0.6 ≤ x/L < 0.75

0.75 ≤ x/L ≤ 1.0

(4x/L + 0.2)

0 ≤ x/L < 0.2

0.2 ≤ x/L < 0.3

0.5 < x/L < 0.6

Value

0.5 < x/L < 0.55

(10x/L − 5.5)+

0.55 ≤ x/L < 0.65

4

(1 − x/L)

(6.5 − 10x/L)

0.65 ≤ x/L < 0.75 0.75 ≤ x/L ≤ 1.0

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

4

(1 − x/L)

Page 17

Sagging condition

Part 5 Chapter 2 Section 3

Hogging condition

2.3 Permissible still waterloads for harbor/sheltered water operations 2.3.1 Permissible hull girder bending moment for harbour/sheltered water operations The permissible hull girder bending moment for all loading conditions for harbour/sheltered operations in hogging and sagging shall comply with Pt.3 Ch.5 Sec.2 [1.7], applying a correction factor:

2.3.2 Permissible hull girder shear force for harbour/sheltered water operations The positive and negative permissible hull girder shear forces for all loading conditions for harbour/sheltered operations in hogging and sagging shall comply with Pt.3 Ch.5 Sec.2 [2.3], applying a correction factor:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 18

where:

Mst

= design still water torsional moment, see Pt.3 Ch.4 Sec.4 [2.3.1].

The value may be taken as a constant value along the whole ship length.

3 Loading condition 3.1 Standard design loading conditions 3.1.1 General The standard design loading conditions given in this sub-section shall be considered in addition to the standard loading conditions given in Pt.3 Ch.4 Sec.8 [1]. 3.1.2 Seagoing design loading conditions The following seagoing design loading conditions shall be included in the loading manual: — homogeneous cargo loading conditions at maximum draught — homogeneous cargo loading conditions at maximum draught with one 40 ft container bay empty — ballast loading conditions. Guidance note: For operational flexibility, it is recommended to consider the following loading conditions: —

loading condition with maximum stack weights at the aft/forward ends of the ships ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 19

Part 5 Chapter 2 Section 3

2.3.3 Permissible hull girder static torsional moment for harbour/sheltered water operations The positive and negative hull girder static torsional moment, in kNm, for all loading conditions for harbour/ sheltered operations in hogging and sagging shall comply with:

1 General The hull girder strength assessment shall be carried out in accordance with Pt.3 Ch.5. This section specifies additional requirements to be applied in lieu of particular requirements in Pt.3 Ch.5.

2 Strength assessment 2.1 Corrosion margin and net-scantlings 2.1.1 Net scantlings The longitudinal strength shall be assessed using the net thickness approach on all scantlings. The net offered thickness, toff in mm, for the plates, webs and flanges is obtained following the requirements given in Pt.3 Ch.3 Sec.2 by:

where

α is a corrosion addition factor whose values are defined in Table 1.

Table 1 Values of corrosion addition factor

α

Structural requirement

Property/analysis type

Strength assessment, see [2.4]

Section properties

0.5

Buckling strength, see [2.5]

Section properties (stress determination)

0.5

Buckling capacity

1.0

Section properties

0.5

Buckling/collapse capacity

0.5

Hull girder ultimate strength, see [2.6]

2.1.2 Corrosion addition The corrosion addition tc shall be determined according to the requirement given in Pt.3 Ch.3 Sec.3 by using the corrosion additions as given in Table 2. Table 2 Corrosion addition for one side of a structural member One side corrosion addition tc1 or tc2 [mm]

Compartment type Exposed to sea water

1.0

Exposed to atmosphere

1.0

Ballast water tank

1.0

Void and dry spaces

0.5

Fresh water, fuel oil and lube oil tank

0.5

Accommodation spaces

0.0

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 20

Part 5 Chapter 2 Section 4

SECTION 4 HULL GIRDER STRENGTH

1.0

Compartment types not mentioned above

0.5

2.2 Load cases Still water bending moments MSW, in kNm, and still water shear forces QSW, in kN, shall be calculated at each section along the ship length for design loading conditions as specified in Sec.3 [3]. For the longitudinal strength assessment, the maximum hogging and sagging load cases given in Table 3 shall be checked. For each load case the still water condition at each section as defined in Sec.3 [3] shall be combined with the wave condition as defined in Sec.3 [2],see also Figure 1. Table 3 Combination of still water and wave bending moments and shear forces Bending moment

Load case

M

SW

M

WV

Hogging

M

SWmax

M

WVH

Sagging

M

SWmin

M

WVS

Shear force Q

SW

Q

WV

QSWmax for x ≤ 0.5L

QWVmax for x ≤ 0.5L

QSWmin for x > 0.5L

QWVmin for x > 0.5L

QSWmin for x ≤ 0.5L

QWVmin for x ≤ 0.5L

QSWmax for x > 0.5L

QWVmax for x > 0.5L

where:

MWVH

= wave bending moment in hogging at the cross section under consideration, to be taken as the positive value of MWV as defined in Sec.3 Table 1

MWVS

= wave bending moment in sagging at the cross section under consideration, to be taken as the negative value of MWV as defined Sec.3 Table 1

QWVmax

= maximum value of the wave shear force at the cross section under consideration, to be taken as the positive value of QWV as defined Sec.3 Table 2

QWVmin

= minimum value of the wave shear force at the cross section under consideration, to be taken as the negative value of QWV as defined Sec.3 Table 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 21

Part 5 Chapter 2 Section 4

Container holds

Part 5 Chapter 2 Section 4 Figure 1 Load combination to determine the maximum hogging and sagging load cases as given in Table 3

2.3 Hull girder stress 2

The hull girder stresses in N/mm shall be determined at the load calculation point under consideration, for the hogging and sagging load cases defined in [2.2] as follows: Bending stress:

Shear stress:

where:

γS

= partial safety factor for still water moment and still water shear force, to be taken as:

γW

= partial safety factor for the vertical wave bending moment and vertical wave shear force, to be taken as:

qv

= unit shear flow for hull girder vertical shear force, in mm , for the plate considered based on net offered thickness toff, in mm.

γ S = 1.0 γ W = 1.0

-1

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 22

2.4.1 Stiffness criterion The following requirement to hull girder moment of inertia shall apply in lieu of in Pt.3 Ch.5 Sec.2 [1.5]. The 4 net moment of inertia, considering the two load cases hogging and sagging as listed in [2.2], in m , is not to be less than:

2.4.2 Yield strength The following requirement to hull girder yield strength shall apply in lieu of Pt.3 Ch.5 Sec.2 [1.4]. Acceptance criterion The yield strength assessment shall check, for each of the load cases hogging and sagging as defined in 2 [2.2], that the equivalent hull girder stress σvm, in N/mm , is less than the permissible stress σperm, in N/ 2 mm , as follows:

where:

σvm

=

σperm = γ1

= partial safety factor for material, to be taken as:

γ1= γ2

= partial safety factor for load combinations and permissible stress, to be taken as: for bending strength assessment

γ 2 = 1.74 for x/L ≤ 0.1 γ 2 = 1.24 for 0.3 ≤ x/L ≤ 0.7 γ 2 = 1.74 for x/L ≥ 0.9 Intermediate values γ2 shall be obtained by linear interpolation. for shear stress assessment

γ 2 = 1.13. γ2 for bending strength assessment can be decreased to γ2 = 1.24, if the class notation RSD in accordance with Pt.6 Ch.1 Sec.8 has been applied. For the ranges outside 0.4L the partial safety factor

Bending strength The assessment of the bending stresses shall be carried out at the following locations of the cross section: — at bottom — at deck — at top of hatch coaming

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 23

Part 5 Chapter 2 Section 4

2.4 Yield strength assessment

The following combination of hull girder stress as defined in [2.3] shall be considered:

σ

σhg

x

=

τ

=0

Shear strength The assessment of shear stress shall be carried out for all structural elements that contribute to the shear strength capability. The following combination of hull girder stress as defined in [2.3] shall be considered:

σ

x

=0

τ

=

τhg

2.5 Buckling assessment In case of structural members contributing to the longitudinal strength and subjected to compressive stresses resulting from the total vertical bending moment according to [2.3] and/or subjected to shear forces resulting from the total vertical shear force according to [2.3] shall be examined for sufficient resistance to buckling according to Pt.3 Ch.8 Sec.3 [3]. For this purpose the following load combinations shall be investigated: — σhg and 0.7τhg — 0.7σhg and

τhg.

The stresses shall be determined according to [2.3].

2.6 Ultimate hull girder strength assessment 2.6.1 General The ultimate hull girder strength shall be assessed following the requirements in Pt.3 Ch.5 Sec.4. Corrosion additions shall be considered in accordance with [2.1]. The hull girder ultimate moment capacity MU, shall be calculated with the following partial safety factors:

γM

= partial safety factor for the hull girder ultimate bending capacity, covering material, geometric and strength uncertainties, to be taken as:

γDB

= partial safety factor for the hull girder ultimate bending capacity, covering the effect of double bottom bending, to be taken as:

γ γ γ

M

= 1.05

DB

= 1.15 for hogging condition

DB

= 1.0 for sagging condition.

The factor γDB for hogging condition may be reduced based upon agreement with the Society, for cross sections where the breadth of the inner bottom is less than that at amidships or where the double bottom structure differs from that at amidships, e.g. engine room sections.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 24

Part 5 Chapter 2 Section 4

— at any point where there is a change of steel yield strength.

where:

γS γW γM γDB

= partial safety factor for the still water bending moment, to be taken as:

γ

= 1.0

= partial safety factor for the vertical wave bending moment. to be taken as:

γ

W

= 1.2

= partial safety factor for the vertical hull girder bending capacity, to be taken as:

γ

M

= 1.05

= partial safety factor for the double bottom bending effect. The factor γDB for hogging condition may be reduced where the double bottom breadth of the inner bottom is less than that amidships or where the double bottom structure differs from that at amidships, e.g. engine room sections

γ γdU

S

DB

= 1.1 for hogging condition

= partial safety factor reducing the effectiveness of whipping during collapse (dynamic collapse effect), to be taken as:

γ

dU

= 0.9 unless analysed for a specific ship

γWH = in general, the partial safety factor for the additional whipping contribution shall be determined as follows:

γWH = for ships with the class notation HMON(G), the partial safety factor for the additional whipping contribution shall be determined as follows:

γWH = for ships with class notation WIV, the partial safety factor for additional whipping contribution may be substituted with the direct calculated ship specific value according to DNVGL-CG-0153

α

= bow flare angle, in degrees, between a vertical line and a tangential plane of side plating, measured at 0.05L aft of F.E. and between still water line at scantling draft and upper deck

α= with

cL

a1, a2 and hd according to Figure 2

= distribution factor to be taken as: 1.0 for x/L ≤ 0.5 sin(πx/L) for x/L > 0.5

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 25

Part 5 Chapter 2 Section 4

2.6.2 Additional requirements for ships with B > 32.26m The ultimate hull girder strength considering the effect of whipping shall be assessed by the following requirement for hogging and at positions as given in Pt.3 Ch.5 Sec.4 [1.1.2].

= contract speed in knots, at design draft with 85% MCR and 15% sea margin. If the contract speed, Vd, is specified at another x% MCR and y% sea margin, it can be converted by the following formula:

0.05

Figure 2 Determination of bow flare angle

α

Guidance note: For ships with the following characteristics: —

rule length L > 290 m

—

breadth B > 47 m

—

bow flare angle, see [2.6.2] α > 55°

—

ship contract speed, see [2.6.2] V > 25 knots

an advanced assessment using methods based on direct hydrodynamic analysis including whipping and springing or model test (level 2) following class guideline DNVGL-CG-0153 is recommended. This is also recommended for container ships with block coefficient cB, being outside the range 0.6 to 0.7 or with vessel contract speed, V, of less than 20 kn. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 26

Part 5 Chapter 2 Section 4

V

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4 [2].

1 General The hull local scantlings shall be calculated according to Pt.3 Ch.6 and Pt.3 Ch.10. Additional local strength requirements are provided in the following sub-sections.

2 Primary supporting members 2.1 Prescriptive requirements 2.1.1 Application The requirements given in [2.1.2] to [2.1.4] shall be applied to double bottom longitudinal girders. Lower scantlings can be accepted, if the requirements, as specified in Sec.6 for double bottom longitudinal girders are satisfied and the longitudinal strength requirements, as specified in Sec.6 are fulfilled. 2.1.2 Thickness of double bottom centre girder The net thickness, tm, in mm, of the centre girder shall not be less than:

where:

h

= depth, in mm, of the centre girder, to be taken as: h = 350 + 45 · ℓ with h ≥ 600

ha ℓ

= as built depth, in mm, of centre girder = unsupported span of the floor plates, in m, to be taken equal to the distance between longitudinal side bulkheads, however not less than ℓ ≥ 0.8 B.

2.1.3 Thickness of double bottom side girder The net thickness tm, in mm, of the side girders shall not be taken less than:

where:

ha

= as built depth, in mm, of side girders.

2.1.4 Minimum net thickness of non-tight transverse structures in way of side structure and longitudinal bulkhead The net thickness shall not be taken less than the required minimum thickness for non-tight bulkhead as given in Pt.3 Ch.6 Sec.3 [1.1.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 27

Part 5 Chapter 2 Section 5

SECTION 5 HULL LOCAL SCANTLINGS

3.1 Wave breakers 3.1.1 If containers are intended to be carried above the weather deck at a location forward of 0.15 L from F.E. a wave breaker shall be fitted in accordance with the requirements given in Pt.3 Ch.10 Sec.6 [10].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 28

Part 5 Chapter 2 Section 5

3 Special requirements

1 General Finite element analysis shall be carried out according to general assumptions, methodology and requirements for the finite element analysis given in Pt.3 Ch.7 and according to methods and procedures given in the Society's document DNVGL-CG-0127, Finite element analysis, unless otherwise specified in this section.

2 Cargo hold finite element analysis 2.1 Application Cargo hold finite element analysis shall be carried out for the midship region and applied for one hold with typical hold arrangement.

2.2 Scope The cargo hold finite element analysis in midship region shall be used to assess the structural adequacy of all primary supporting members. Guidance note: The evaluation of the yield and buckling criteria is of particular importance for the following structural members: —

inner bottom

—

outer bottom

—

double bottom girders

—

double bottom floors

—

vertical girders of the transverse bulkheads. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3 Design load combinations 2.3.1 Design load combinations as given in Table 1 are based on typical cargo hold arrangements, i.e. two 40 ft. bays are arranged in each cargo hold and one non-watertight support transverse bulkhead is arranged in between the two bays. The loading patterns are illustrated in Table 1. If cargo hold arrangements are different from the above assumption, the design load conditions shall be agreed with the Society. 2.3.2 The design load combinations as given in Table 1 are required for cargo hold finite element analysis. If more severe container loading conditions exist, such conditions combined with critical dynamic load cases shall be agreed with the Society and shall be included in the analysis.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 29

Part 5 Chapter 2 Section 6

SECTION 6 FINITE ELEMENT ANALYSIS

No. Description

Loading pattern aft mid fore

Container weights and tank content

Draught

% of perm. SWBM

% of perm. SWSF

Dynamic load case

Seagoing conditions

on deck: max 40 ft stack weight LC1

LC2

40 ft (1) Heavy

40 ft (1) Light

in hold: 30.5 t/FEU not exceeding max 40 ft stack weight

HSM-2 Tsc

100% (hog.)

≤ 100%

BSR-1P BSP-1P

on deck: 90% of max 40 ft stack weight not exceeding 17 t/FEU

HSM-2

in hold: 55% of max 40 ft stack weight not exceeding 16.5 t/FEU

Tsc

100% (hog.)

≤ 100%

in hold: 30.5 t/FEU not exceeding max 40 ft stack weight

HSA-2 FSM-2 BSR-1P BSP-1P

on deck: max 40 ft stack weight Aft bay empty

FSM-2

all tanks empty

all tanks empty

LC 3a

HSA-2

TSC

100% (hog.)

≤ 100%

100% (hog.

≤ 100%

HSM-2 HSA-2 FSM-2

all tanks empty

LC 3b

Forward bay empty

on deck: max 40 ft stack weight in hold: 30.5 t/FEU not exceeding max 40 ft stack weight

TSC

HSM-2 HSA-2 FSM-2

all tanks empty

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 30

Part 5 Chapter 2 Section 6

Table 1 Standard design load combinations for cargo hold finite element analysis

LC4

20 ft (1) Heavy

Loading pattern aft mid fore

Container weights and tank content

on deck: max 20 ft. stack weight if mixed stowage is applicable, max 20 ft. + 40 ft. stack weight in hold: 24t/TEU not exceeding max 20 ft. stack weight

Draught

% of perm. SWBM

0.9Tsc

100% (sag. or min. hog.)

% of perm. SWSF

Dynamic load case

HSM-1 ≤ 100%

HSA-1 FSM-1 BSR-1P BSP-1P

all tanks empty

LC5

Heavy deck light (1) hold

on deck: max 20 ft stack weight, if mixed stowage is applicable, max 20 ft + 40 ft stack weight

HSM-1 0.9Tsc

in hold: 16 t/FEU

100% (sag. or min. hog.)

≤ 100%

LC6

Pitching

(1)

in hold: 30.5 t/FEU not exceeding max 40 ft stack weight

FSM-1 BSR-1P BSP-1P

all tanks empty

on deck: max 20 ft stack weight, if mixed stowage is applicable, max 20 ft + 40 ft stack weight

HSA-1

HSM-1 Tsc

100% (sag. or min. hog.)

≤ 100%

HSA-1 FSM-1 BSR-1P BSP-1P

all fuel oil tanks full all ballast tanks full Damaged condition

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 31

Part 5 Chapter 2 Section 6

No. Description

Loading pattern aft mid fore

Container weights and tank content

Draught

% of perm. SWBM

% of perm. SWSF

Dynamic load case

100% (sag. or min. hog.)

-

Static (3) only

on deck: max 40 ft stack weight LC7

Flooded damage (2) condition

in hold: centre: flooded

T

DAM

adjacent: 20t/FEU all ballast tanks full at inclined side

Notes: 1)

For asymmetrical structures BSR-1S and BSP-1S shall be investigated additionally.

2)

With deepest equilibrium waterline TDAM in a heeled damage condition where the considered hold is one of the flooded compartments. Although this is a typical scenario with two or three flooded holds. in the FE-analysis only the center cargo hold is flooded.

3)

Heeled condition shall be considered at least for inner pressure in the flooded cargo hold, for outer pressure on the shell and for container forces, based on design ZDAM and ΘDAM as defined in Pt.3 Ch.4 Sec.6 [1.2.7].

2.4 Acceptance criteria 2.4.1 Yield Verification against the yield criteria shall be carried out according to Pt.3 Ch.7 Sec.3 [4.2]. 2.4.2 Buckling Verification against the buckling criteria shall be carried out according to Pt.3 Ch.8 Sec.4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 32

Part 5 Chapter 2 Section 6

No. Description

3.1 Application Fuel oil deep tank finite element analysis is required for ships with typical fuel oil deep tank arrangements, i.e. tanks are below the deck house in a twin-island design or tanks are below one 40 ft container bay in a single-island design.

3.2 Scope The fuel oil deep tank finite element analysis shall be used to assess the structural adequacy of all primary supporting members. Guidance note: The evaluation of the yield and buckling criteria is of particular importance for the following structural members: —

inner bottom

—

outer bottom

—

double bottom girders

—

double bottom floors

—

transverse bulkheads with attached stringers

—

longitudinal bulkheads with attached stringers

—

vertical girders and/or pillars. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.3 Modelling principles 3.3.1 The analysis model shall extend from one cargo hold aft of the aftermost fuel oil tank transverse bulkhead to one cargo hold forward of the foremost fuel oil tank transverse bulkhead. 3.3.2 The FE models shall be based on gross scantlings. 3.3.3 If deck houses in a twin-island design are not included in the FE model, the static self-weight of these structures shall be included in the model by applying line loads.

3.4 Design load combinations 3.4.1 Design load combinations as given in [3.4.3] are based on typical fuel oil deep tank arrangements, i.e. tanks are below the deck house in a twin-island design or tanks are below one 40 ft container bay in a singleisland design. The loading patterns are illustrated in Table 1. If fuel oil deep tank arrangements are different from the above assumption, the design load conditions shall be agreed on by the Society. 3.4.2 In general, heeled conditions of fuel oil deep tank do not need to be considered. However, if any fuel oil deep tank is wider than 50% of ship’s breadth B, heeled seagoing conditions shall be agreed with the Society and shall be applied in addition to load conditions as given in [3.4.3]. 3.4.3 The design load combinations as given in Table 2 are required for fuel oil deep tank finite element analysis.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 33

Part 5 Chapter 2 Section 6

3 Fuel oil deep tank finite element analysis

No.

Description

DT1-a Ballast departure

Loading pattern aft mid fore

Tank content and container weights

Draught

all fuel oil deep tanks full all ballast tanks full

TBAL

all container bays empty

% of perm. SWBM

SWBM in Ballast condition

% of perm. SWSF

Dynamic load case

HSM-1 ≤ 100%

HSA-1 FSM-1

(1)

DT1

DT1-b Ballast departure

relevant fuel oil deep tanks are full and empty so that each longitudinal bulkhead separating fuel oil deep tanks has lateral pressures from first side

TBAL

SWBM in Ballast condition

HSM-1 ≤ 100%

HSA-1 FSM-1

(1)

all ballast tanks full all container bays empty

DT1-c Ballast departure

relevant fuel oil deep tanks are full and empty so that each longitudinal bulkhead separating fuel oil deep tanks has lateral pressures from second side

TBAL

SWBM in Ballast condition (1)

HSM-1 ≤ 100%

HSA-1 FSM-1

all ballast tanks full all container bays empty

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 34

Part 5 Chapter 2 Section 6

Table 2 Standard design load combinations for fuel oil deep tank finite element analysis

Description

DT2-a Tank test

Loading pattern aft mid fore

Tank content and container weights

Fuel oil deep tank filling is for tank test according to Pt.3 Ch.4 Sec.6 [4.1] all fuel oil deep tanks full

Draught

TBAL

% of perm. SWBM

SWBM in Ballast condition

% of perm. SWSF

Dynamic load case

≤ 100%

Static only

≤ 100%

Static only

≤ 100%

Static only

(1)

all ballast tanks empty all container bays empty

DT2

Fuel oil deep tank filling according to Pt.3 Ch.4 Sec.6 [4.1]

DT2-b Tank test

relevant fuel oil deep tanks are full and empty so that each longitudinal bulkhead separating fuel oil deep tanks has lateral pressures from first side

TBAL

SWBM in Ballast condition (1)

all ballast tanks empty all container bays empty Fuel oil deep tank filling according to Pt.3 Ch.4 Sec.6 [4.1]

DT2-c Tank test

relevant fuel oil deep tanks are full and empty so that each longitudinal bulkhead separating fuel oil deep tanks has lateral pressures from second side

TBAL

SWBM in Ballast condition (1)

all ballast tanks empty all container bays empty

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 35

Part 5 Chapter 2 Section 6

No.

Description

Loading pattern aft mid fore

Tank content and container weights

Draught

% of perm. SWBM

% of perm. SWSF

0.90TSC

100% (sag. or min. hog.)

≤ 100%

100% (hog.)

≤ 100%

Dynamic load case

all tanks empty

20 ft Heavy

DT3

on deck: max 20 ft stack weight, if mixed stowage is applicable, max 20 ft + 40 ft stack weight in hold: max 20 ft stack weight, if unavailable 24t/ TEU

HSM-1 FSM-1

all tanks empty 40 ft Light

DT4

on deck: 90% of max 40 ft stack weight not exceeding 17 t/FEU

Tsc

HSA-1

HSM-2

in hold: 16 t/FEU

HSA-2 FSM-2

Note: 1)

Still water bending moment corresponding to the ballast departure loading condition from loading manual.

3.5 Acceptance criteria Yield and buckling criteria is given in [2.4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 36

Part 5 Chapter 2 Section 6

No.

1 General General assumptions, requirements as well as loading conditions for prescriptive fatigue strength assessment are given by Pt.3 Ch.9. Methods and procedures for the fatigue strength assessment of the hull structures are described in the Society's document DNVGL-CG-0129, Fatigue assessment of ship structures.

1.1 Scope 1.1.1 General This section is applicable for container ships having a rule length, L, of 90 m or greater. Prescriptive fatigue strength assessment shall be performed for structure details which are predominantly subjected to cyclic loads. The prescriptive fatigue strength assessment is applicable to structures that are mainly loaded by longitudinal hull girder stresses and local pressures. 1.1.2 Details to be assessed by prescriptive fatigue assessment In particular, the following details shall be considered for container ships: — end connections of longitudinal stiffeners to transverse web frames and transverse bulkheads — welded details in the upper part of the hull girder, e.g., transverse butt welds of plate and stiffeners, hatch cover resting pads, equipment holders, etc. — knuckles and discontinuities of longitudinal structural members, e.g. hatch coamings, in the upper part of the hull girder. 1.1.3 Longitudinal extent for prescriptive fatigue assessment Structural details subject to significant dynamic stresses between the fore and the aft end of the cargo hold area shall be assessed.

2 Prescriptive fatigue strength calculations 2.1 Longitudinal stiffener end connections 2.1.1 For side structures comprising relatively low lateral bending stiffness, e.g. due to omission of stringers or reduced number of transverse web frames, additional stresses due to relative deflections of supporting transverses shall be considered. 2.1.2 The additional stresses due to relative displacement shall be calculated as described in DNVGLCG-0129 Sec.4 [7], based on relative displacements taken from, e.g., global or cargo hold finite element analysis. If no results are available from finite element analysis for the specific ship, relative displacements may be assumed as for a similar ship. The Society decides whether a certain ship can be considered as similar to the specific ship.

2.2 Welded details in the upper part of the hull girder For welded details in the upper part of the hull girder, e.g. transverse butt welds, hatch cover resting pads, equipment holders etc., the evaluation of permissible stress concentration factors or required FAT classes according to DNVGL-CG-0129 Sec.3 [5] are applicable.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 37

Part 5 Chapter 2 Section 7

SECTION 7 FATIGUE

Knuckles and discontinuities of longitudinal structural members in the upper part of the hull girder, e.g. of hatch coamings, shall be assessed using local fine mesh FE models as described in DNVGL-CG-0129 Sec.6. Holes and openings may be assessed by use of appropriate stress concentrations factors as given in DNVGLCG-0129 App.A.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 38

Part 5 Chapter 2 Section 7

2.3 Knuckles and discontinuities in the upper part of the hull girder

Part 5 Chapter 2 Section 8

SECTION 8 CONTAINER SECURING ARRANGEMENT Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4.

G

= container’s gross mass, in t, as given in [4.1.2].

1 General 1.1 Container securing arrangements 1.1.1 Container securing arrangement plan A container securing arrangement plan shall be submitted according to Sec.1 [2.1], complying with the following: — stowage of containers on deck, see [2] — stowage of containers below deck, see [3] — strength evaluation of container securing arrangements, see [8.1]. The container securing and arrangement plan shall include minimum one metacentric height, GM. The GM value shall not be less than the minimum GM value included in the approved trim and stability booklet for the respective draught. The approved container securing arrangement plan shall be kept on board. Guidance note: It is strongly recommended for ships designed for carrying containers on deck to ensure the compliance with Code of Safe Practice for Cargo Stowage and Securing (CSS Code) Annex 14 adopted by MSC.1/Circ. 1352 and related IACS UI SC265, considering design aspects to be implemented at the newbuilding stage. The application of the class notation SAFELASH visualizes compliance with CSS Code Annex 14 to all relevant parties including flag administrations and port state authorities. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.2 Stowage of containers Containers shall be stowed and secured in accordance with the approved container securing arrangement plan and checked for compliance with the requirements given in [8.1] by the lashing computer certified in accordance with [9]. All container securing devices shall be delivered with product certificates in accordance with Sec.1 [2.2]. Container securing equipment need only to be carried on board to the extent the ship is carrying containers.

1.2 Container securing structures 1.2.1 Lashing bridge If the ship is equipped with lashing bridges, a structural drawing shall be submitted according to Sec.1 [2.1] and comply with the requirements given in [8.2]. 1.2.2 Cell guides A structural drawing shall be submitted according to Sec.1 [2.1] and comply with the requirements given in [8.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 39

1.2.4 Other container securing structures If the ship is equipped with other container securing structures, a structural drawing shall be submitted for approval and comply with the requirement given in [8.2].

2 Stowage of containers on deck 2.1 General 2.1.1 Relative movement of container support fittings For containers resting on container support fittings which may move relative to each other, e.g. containers that are partly resting on hatch covers and partly resting on container stanchions, the container support fittings shall be arranged so that the relative movement does not lead to permanent deformation of the containers. Guidance note: To prevent damages to the container itself caused by relative movement of supporting fittings, sliding plates or foundations with elongated apertures may be provided. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2 Stowage on deck with neither lashing nor lateral rigid support 2.2.1 Containers in one layer Containers carried in one layer shall be secured against tilting and shifting by locking devices arranged at their lower corner castings. 2.2.2 Containers in several layers If containers are stowed in several layers, locking devices shall be arranged between the container layers. Containers located in the lowermost layer shall be locked as well at their lower corner castings.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 40

Part 5 Chapter 2 Section 8

1.2.3 Container stanchions If the ship is equipped with container stanchions, a structural drawing shall be submitted according to Sec.1 [2.1] and comply with the requirements given in [8.2].

Part 5 Chapter 2 Section 8

2.3 Stowage on deck with lashing but without lateral rigid support 2.3.1 Lashing arrangement A typical lashing arrangement is shown in Figure 1 for illustration.

Figure 1 Typical arrangement of lashings 2.3.2 Locking devices Locking devices shall be arranged between container layers and below lowest container layer between container corner castings/container support fittings. 2.3.3 Direction of containers All wall ends and all door ends of containers shall be stowed in the same direction. If this requirement is not met, the stack in question shall be examined separately according to [8.1]. 2.3.4 Lashing In case single lashings are used, lashing elements such as lashing rods shall be fitted to the containers' lower corner castings. If upper corner castings are utilized instead, the allowable lashing loads shall be decreased according to DNVGL-CG-0060 Sec.3 [2]. Guidance note: When lashings of containers are used, pretension of lashings should be kept as small as possible. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3.5 Vertical lashings For vertical lashings, lashing shall be loose to equalize the clearance between the twistlock and corner casting/container support fittings. Guidance note: This equalization may be achieved by spring elements. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 41

For vertical clearance, the following values shall be applied: — conventional and semi-automatic twistlooks: 12 mm — Fully automatic locks (latch lock): 20 mm. Guidance note: In case lashing rods with spring elements or similar are fitted, 0 mm may be applied for vertical clearance. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Figure 2 Internal and external lashings

2.4 Stowage on deck with lateral rigid support 2.4.1 Cell guides on deck For containers stowed with both ends supported by cell guides, they may be treated as containers stowed with cell guided below the deck, and shall comply with [3.1]. The 20 ft containers may be stowed in 40 ft cell guides according to [3.1.8] provided that outermost stacks are additionally secured against green sea loads in accordance with [2.4.3]. 2.4.2 Over stow of containers above cell guide Containers, with any part of them, stowed exceeding the upper end of cell guides shall be secured according to [2.3]. The additional compression/tension forces on container post due to tilting moment shall be included in the calculations. 2.4.3 Containers subject to green sea loads Containers stowed in positions subject to green sea loads shall be additionally secured by locking devices, by container support fittings of increased height and/or by reinforced lashings. Guidance note: For ships with low freeboard and when it is possible that part of container stacks may submerge into the sea, buoyancy loads may have to be considered in the design of the lashing system. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 42

Part 5 Chapter 2 Section 8

2.3.6 Cross lashings If external cross lashing systems are used, see Figure 2, the calculation of lashing forces in accordance with [8.1] shall consider the vertical clearance between the twistlook and corner casting/container support fitting.

3.1 Stowage below deck in cell guides 3.1.1 General Cell guides for containers may be welded to the ship's hull or be arranged in a detachable manner (screwed connections, suspended structures). 3.1.2 Lateral support of cell guides Cell guides at transverse or longitudinal bulkheads shall be laterally supported by the bulkhead with horizontal web plates or other suitable elements. 3.1.3 Vertical guide rails of cell guides Vertical guide rails consist typically of equal sided steel angle bars. On account of abrasion and local forces, e.g., due to jamming occurring when hoisting and lowering of containers, the thickness of angle bars shall be at least 12 mm. Where vertical guide rails consist of several steel angle bars, these bars shall be connected to each other by horizontal web plates arranged at least at the level of lateral supports and additionally between lateral supports depending on bending moments induced by containers due to random stowage of 8’6” and 9’6” high containers. 3.1.4 Guide heads Top ends of guide rails shall be fitted with sufficiently strong guide heads, according to operating conditions. To minimise the impact on fatigue strength of longitudinal hull structures, horizontal supports for guide heads in the area close to hatch corners shall be arranged on transverse bulkheads only. Guidance note: To transfer shear forces caused by loading and offloading, vertical supports for guide heads should be arranged on transverse bulkheads. Vertical supports for guide heads may be fitted to the longitudinal bulkhead. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.5 Self-supporting cell guides The self-supporting cell guides shall consist of transverse ties and longitudinal ties to which steel guide rails are attached. The self-supporting cell guides shall be sufficiently secured to the inner hull structure. Guidance note 1: The transverse ties should be fitted at the level of the container corners. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: Cell guides may consist of main girders (e.g., I-beams) to which steel guide angles are attached. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.6 Movable cell guides Movable cell guides shall be provided with means to prevent lifting during discharge operation of containers.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 43

Part 5 Chapter 2 Section 8

3 Stowage of containers below deck

Guidance note: When building tolerance of cell guides is taken into consideration, the limits above may be increased by 6 mm in transverse and longitudinal directions. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.8 20 ft containers in 40 ft cell guides In cases where the vertical dimensionless acceleration factor as given in [4.5.3] exceeds 1, the 20 ft containers shall be secured against lifting. In a mixed stowage of 20 ft and 40 ft containers, the 40 ft containers shall be stowed on top of 20 ft containers. In order to prevent sliding in transverse and longitudinal direction: — for 20 ft containers stacked on top of each other, the 20 ft containers shall be secured together by a minimum of two stacking cones with at least one stacking cone fitted in the free end — for the lowermost 20 ft container, the corners in the cell guide end and in the free end shall be secured by stacking cones — for mixed stowage of 20 ft and 40 ft containers, the lowermost 40 ft container shall be secured to the uppermost 20 ft container by two stacking cones in each end.

4 Loads acting on containers 4.1 General 4.1.1 Transverse, longitudinal and vertical loads on containers given below shall be understood as forces aligned in the ship’s coordinate. They include static gravity loads, dynamic loads caused by the ship’s surge, pitch, heave, yaw, sway and roll motions, as well as wind loads. 4.1.2 The following values for minimum and maximum gross mass of containers are assumed for subsequent calculations (see DNVGL-CG-0060 App.B): 20 ft 40 ft 45 ft

minimum

2.5 tons

maximum

30.5 tons

minimum

3.5 tons

maximum

30.5 tons

minimum

4.5 tons

maximum

30.5 tons.

4.1.3 The height of the centre of gravity of the container and its cargo is assumed at 45% of container height. 4.1.4 A force reduction in calculations due to friction between container layers shall not be considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 44

Part 5 Chapter 2 Section 8

3.1.7 Clearances Clearance of standard containers in guide rails shall not exceed 25 mm athwartships and 38 mm in the foreto-aft direction. Maximum clearance in the fore-to-aft direction includes the deformation of the cell-guide system itself.

4.2.1 Lateral wind loads in ship’s transverse direction, Fw, in kN, shall be considered on exposed side walls of containers according to Table 1. Table 1 Wind load Fw per container

2)

Container type

1st tier

1)

2nd tier and higher

20 ft

40 ft

30

60

15

30

Notes: 1)

The load Fw for the first tier accounts additionally for green sea loads on outermost stacks. The green sea loads may be neglected in case of open holds of hatchcoverless ships.

2)

The stated values are valid for 8' 6" high containers. For other container heights and lengths, the wind force has to be adjusted according their side wall area.

4.2.2 Wind loads may be neglected for uppermost containers in partly shielded stacks where the difference in height to shielding stack is less than 0.33 × 8 ft 6 inches. For partly shielded stacks where the shielding stack does not cover the whole length of the partly shielded stack, wind loads according to Table 1 shall be applied according to the longitudinal overhang areas exposed to wind. See Figure 3 for illustrations.

Figure 3 Example of wind application on partly shielded stacks If inside positioned stacks form a transversal gap larger than 0.5 B for ships with B > 16 m or more than three rows wide for ships with B ≤ 16 m, free standing stacks shall be imposed with wind loads according to Table 1. And the wind loads may be reduced to 0.33 of loads given in Table 1. For smaller gaps than the above, wind loads may be neglected.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 45

Part 5 Chapter 2 Section 8

4.2 Wind loads

4.3.1 Transverse forces The transverse force in the ship’s transverse direction, Fq, in kN, acting on a container shall be calculated as following:

where:

bq Fw

= transverse dimensionless acceleration factor, as defined in [4.3.2] = wind loads, in kN, as defined in [4.2].

Where containers or container stacks placed side by side are coupled to form container blocks, transverse loads acting on containers, such as wind loads on outermost container stacks, may be equally distributed over a maximum of three stacks. 4.3.2 Transverse dimensionless acceleration factor The transverse dimensionless acceleration factor for unrestricted service, bq, including combined effects of the ship’s motions, shall be calculated as following:

where:

bv bh θ, Tθ R zcont

= dimensionless acceleration in the global vertical direction due to pitch and heave = dimensionless acceleration in the global horizontal direction due to yaw and sway = rolling angle and rolling period = height of roll axis above base line, in m = height of container’s centre of gravity above base line, in m.

In the formula above, values of bv, bh and θ represent simultaneously acting accelerations and roll angle of the ship. They are determined from the respective design values bv,D, bh,D and θD, i.e. the extreme values occurring once in operation of the ship, such that bq attains its maximum value and

The transverse acceleration factor, bq, shall be determined based on a semi-empirical tool. Guidance note: bq may be determined applying the Society's calculation tool for strength evaluation of container securing arrangements, StowLash. In order to obtain bq values for application in other tools, e.g. loading computer systems, the Society will provide a separate software development kit upon request. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

For ships with unusual form and design regarding, e.g. stern and bow shape, the Society may require determination of the transverse acceleration factor, bq, by an alternative calculation method.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 46

Part 5 Chapter 2 Section 8

4.3 Transverse forces

4.4.1 Longitudinal forces The longitudinal force in ship’s longitudinal direction, F, in kN, acting on a container shall be calculated as following:

where:

bℓ

= longitudinal dimensionless acceleration factor, as defined in [4.4.2].

4.4.2 Longitudinal dimensionless acceleration factor The longitudinal dimensionless acceleration factor, bℓ, including combined effects of the ship’s motions, shall be calculated according to Table 2. Table 2 Longitudinal dimensionless acceleration factor bℓ For lowest tier in cargo hold L ≤ 120 m: bℓ = L > 120 m: bℓ = 0.15

For lowest tier on deck For any length of the ship: bℓ = min bℓ = 0.15

Note: The bℓ values for containers located between the lowest tier in the cargo hold and the lowest tier on deck shall be determined by linear interpolation and for containers above the lowest tier on deck by linear extrapolation.

4.5 Vertical forces 4.5.1 Vertical forces in combination with transverse forces The vertical force in ship’s vertical direction acting downwards in combination with transverse forces, Fv1, in kN, acting on a container shall be calculated as following:

where:

bt

= Container position correction factor as given in DNVGL-CG-0060.

4.5.2 Vertical forces in combination with longitudinal forces The vertical force in ship’s vertical direction acting downwards in combination with longitudinal forces, Fv2, in kN, acting on a container shall be calculated as following:

where:

bv

= vertical dimensionless acceleration factor, as defined in [4.5.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 47

Part 5 Chapter 2 Section 8

4.4 Longitudinal forces

bv = F ∙ m where:

F

= coefficient, to be taken as: with

m

= coefficient, to be taken as: for for for

m0

= coefficient, to be taken as: .

5 Design load combinations for container securing arrangements 5.1 Design load combinations 5.1.1 Applicable load combinations for container securing arrangements are listed in Table 3. Table 3 Load combinations for container securing arrangements LC

Description

Vertical loads

Horizontal loads

Wind loads

1

Transverse loading

F

v1

Fq

Yes

2

Longitudinal/vertical loading

F

v2

Fl

No

5.1.2 Transverse loading (LC1) Forces in the lashing system shall be calculated by applying the transverse force Fq according to [4.3.1], combined with the vertical force Fv1 according to [4.5.1]. Wind loads shall be added to wind exposed containers according to [4.2]. 5.1.3 Longitudinal/vertical loading (LC2) Forces in the lashing system shall be calculated by applying the longitudinal force Fl according to [4.4.1], combined with vertical force Fv2 according to [4.5.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 48

Part 5 Chapter 2 Section 8

4.5.3 Vertical dimensionless acceleration factor The vertical dimensionless acceleration factor, bv, including combined effects of the ship’s motions, shall be calculated as following:

6.1 General 6.1.1 Loads Design loads for container securing structures shall be calculated according to [4] with assumptions given in [6.1.2], [6.1.3] and [6.1.4]. 6.1.2 GM Transverse forces shall be calculated according to [4.3] based in metacentric height GM, in m, as given below. 2

GM = 0.04 · B /Z

for B ≤ 32.2 m 2

GM = (B-25.96)/156 · B /Z

for 32.2 m < B ≤ 40 m

2

GM = 0.09 · B /Z

for B > 40 m

where:

Z

= vertical distance, in m, to be taken as: Z = 1.05 ntier + Hst

ntier = number of container tiers for the highest stack on the weather deck, as specified in the container stowage arrangement plan

Hst

= vertical distance between TSC and bottom of container stack on the weather deck, in m.

6.1.3 Height and weight distribution of container stacks In general, container stowage plan for unrestricted service and the metacentric height according to [6.2.1] shall be used for dimensioning of container securing structures. Alternatively, a generic height and weight distribution of container stacks shall be calculated based on an existing stowage plan as follows: Maximum stack weight and maximum stack height according to the container stowage plan in combination with a homogeneous weight distribution shall be used as basis in the design load combinations given in [6.2] to [6.4]. If strength evaluation in accordance with [8.1] of such a container stowage result in container and/or container securing device exceeding any of the acceptance criteria given in [7.1], the vertical centre of gravity of the stack shall be adjusted vertically downwards until the limit on which none of the acceptance criteria given in [7.1] is exceeded. 6.1.4 Lashing arrangement Load combinations of the container securing structures shall be based on lashing/securing patterns as shown in the container stowage plan.

6.2 Design load combinations for lashing bridge 6.2.1 Applicable load combinations are listed in Table 4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 49

Part 5 Chapter 2 Section 8

6 Design load combinations for container securing structures

LC

Description

Vertical loads

Horizontal loads

Wind loads

1

Symmetrical lashing loads from lashing bridge forward and aft side

F

v1

Fq

Yes

2

Asymmetrical lashing loads from lashing bridge forward and aft side separately

F

v1

Fq

Yes

6.3 Design load combinations for cell guide 6.3.1 Applicable load combinations are listed in Table 5. Table 5 Load combinations for cell guide LC

Description

Vertical loads

Horizontal loads

Wind loads

1

Transverse loading

Not Applicable

Fq

Yes

2

Longitudinal/vertical loading

Not Applicable

Fl

No

6.3.2 Transverse loads on cell guides shall be considered for stowage of both 40 ft containers and 20 ft containers as follows: — for stowage of 40 ft containers in cell guides, it is assumed that one-quarter of Fq is transmitted to the cell guide structure at each of the four corner fittings of one longitudinal side wall of the container — for stowage of 20 ft containers in 40 ft cell guides, it is assumed that 1/3 of Fq is transmitted to the cell guide structure at each of the two corner castings of one longitudinal side wall at the container end placed in the cell guide. 6.3.3 Longitudinal loads on cell guides shall be considered for stowage of both 40 ft containers and 20 ft containers as follows: — it is assumed that one-quarter of Fℓ is transmitted to the cell guide structure at each of the four corner fittings of the container’s front end or door end. 6.3.4 Cell guide structures shall be dimensioned for the maximum number of container layers and for the maximum permitted container gross weight in each layer. Combinations of different container heights in a stack, yielding the most severe stresses in cell guide structures, shall be considered.

6.4 Design load combinations for container stanchions 6.4.1 Applicable load combinations are listed in [5.1]. 6.4.2 For container stowage without lateral support, container stanchions and support structures shall be dimensioned based on the most severe simultaneously acting transverse force FT,found, and vertical forces, CPLfound and LFfound, acting on container support fittings calculated according to DNVGL-CG-0060, Container securing. If the bending strength of container stanchions is smaller in the longitudinal than in the transverse direction, the vertical forces on the container support fittings at the stanchion shall be considered as acting simultaneously with the longitudinal force, FL,found, according to DNVGL-CG-0060, Container securing, instead of the transverse forces, FT,found.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 50

Part 5 Chapter 2 Section 8

Table 4 Load combinations for lashing bridge

6.4.4 For to dimension container stanchions, the most unfavourable eccentricity of the vertical compressive force CPLfound acting on container support fittings points shall be applied. 6.4.5 The horizontal design load for container stanchions bending transversely need not to be taken greater than the one producing a deflection considering 10 mm clearance between the container’s locking device and the container support fittings on the hatch covers.

7 Acceptance criteria 7.1 Acceptance criteria for container securing arrangements 7.1.1 Container securing devices Permissible forces for container securing devices shall be taken as the provided safe working load (SWL). Guidance note: Typical values of SWL for container securing devices are given in DNVGL-CG-0060 Sec.3 [3]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.2 Containers Permissible container forces shall be taken as the container strength ratings given in recognized standards. Guidance note: Strength ratings of ISO 20 ft and 40 ft containers are DNVGL-CG-0060 Sec.3 [2]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.2 Permissible forces for container securing structures 7.2.1 Yielding 2 The permissible stresses for container securing structures, in N/mm , shall be taken as following:

where:

σN τ σv

= normal stress, in N/mm² = shear stress, in N/mm² = equivalent stress, in N/mm².

7.2.2 Buckling Buckling capacity for container securing structures shall be according to Pt.3 Ch.8 with allowable buckling utilization factor based on AC-II.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 51

Part 5 Chapter 2 Section 8

6.4.3 Where lashings are arranged at the stanchions, the stanchions shall be dimensioned also considering the most severe vertical and horizontal loads resulting from lashing forces calculated according to DNVGLCG-0060 Sec.4 [3].

8.1 Strength evaluation of container securing arrangements 8.1.1 Strength evaluation of container securing arrangements shall be based on load combinations according to [5] and acceptance criteria according to [7.1]. Guidance note: Strength evaluation methods acceptable to the Society are given in DNVGL-CG-0060, Container securing. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

8.1.2 Lashing bridge deformation For container securing arrangements supported by lashing bridges, the deformation limits given in [8.2.2] shall be included in the strength evaluation. If strength evaluation of lashing bridges in accordance with [8.2] result in greater deformations than given in [8.2.2], such values will be accepted on a case by case basis provided that these deformations values are applied in the strength evaluation of the container securing arrangements.

8.2 Strength evaluation of container securing structures 8.2.1 General Strength evaluation of container securing structures shall be based on load combinations according to [6] and acceptance criteria according to [7.2]. 8.2.2 Lashing bridge Effective structures to transfer lashing forces into coaming or deck structure shall be provided, e.g. shear plates or diagonal bracings. Deformations of the lashing bridges in ship’s transverse direction shall not exceed: — 1-tier high lashing bridge: 10 mm — 2-tier high lashing bridge: 25 mm — 3-tier and higher lashing bridges: 35 mm. Deformations of the lashing bridges in ship’s longitudinal direction shall be limited in particular with regard to asymmetrical load combination to ensure sufficient effectiveness of the lashings. 8.2.3 Cell guide Parts of the cell guide structures considered as components of the ship's hull structure, shall be included in the hull scope. 8.2.4 Container stanchions Detached stanchions shall be designed to safely absorb shocks occurring during normal loading operations. Hatch deformations shall be taken into consideration so that containers situated on stanchions and hatch covers shall not transmit shifting forces (see [2.1.1]). To dimension container support fittings welded into the ship's longitudinal main structures (strength deck, inner bottom, etc.), stresses resulting from the ship’s global loads shall be considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 52

Part 5 Chapter 2 Section 8

8 Strength evaluation

9.1 Application 9.1.1 The lashing computer system shall be certified by the Society. See Sec.1 [2]. 9.1.2 The approved test conditions together with the user manual and the lashing computer certificate shall be kept on board and shall be available to the Society upon request.

9.2 Definition 9.2.1 Lashing computer system A lashing computer system is a computer-based system for calculation and control of container securing arrangements in compliance with the applicable strength requirements as given in this section. The lashing computer system consists of software (calculation program) and hardware (the computer on which it runs). 9.2.2 Approval of software Approval of software means that the Society approves the software for a specific installation on board of a specific ship. 9.2.3 Certification of lashing computer system Certification (installation testing) means that the Society has certified that the lashing computer system works properly on board a specific ship, and that the correct approved version of the software has been installed.

9.3 Approval and certification process The approval and certification process includes the following procedures for each ship: 1) 2) 3)

approval of software which results in approved test conditions approval of computer hardware, where necessary certification of the installed lashing computer system, which results in a lashing computer certificate.

9.4 Hardware approval The approved software is either installed on type approved hardware, or installed on two nominated computers. If the software is installed on two nominated computers, type approval of the hardware may be waived, but both nominated computers shall be equipped with separate screens and printers.

9.5 Software approval 9.5.1 General The approval is based on a review and acceptance of design, calculation method, verification of stored data and test calculation for the specific ship. Approval of the software shall be carried out for each specific ship where the software shall be installed. 9.5.2 Functional requirement The software shall be user friendly, with a graphic presentation of the container arrangement. It shall reject input errors from user, e.g.:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 53

Part 5 Chapter 2 Section 8

9 Lashing computer system

9.5.3 Output data All screen and hardcopy output data shall be presented in a clear and unambiguous manner, with identification of the version number of the calculation program. The software shall be capable of producing printouts of the results numerically. These numeric values shall be presented both as absolute values and as a percentage of the allowable values. 9.5.4 Container stowage The stowage of containers in the software shall be according to the patterns shown in the approved container securing arrangements plan, e.g. mixed stowage of 40 ft. on top of 20 ft. on deck shall only be possible in the software. If the corresponding stowage is listed in the approved container securing arrangement plan. 9.5.5 Test condition, general information The test conditions shall include the following information: — ship’s main data (IMO-No., Lpp, B, D, Tdesign, V) — other optional input parameters as used in approved container securing arrangements plan (such as bilge keel area or Cb) — GM value — position of each container stack — graphical representation of 20 ft-stowage on deck and 40 ft-stowage on deck as well as other container sizes as described in approved container securing arrangements plan, e.g. 45 ft-overstowed on 40 ft., including information as further detailed in [9.5.7] — tabular result representation for aforementioned cases as screen and hard copy output to the user in a clear and unambiguous manner, including information as further detailed in [9.5.6]. 9.5.6 Test condition, result information In test conditions, the following details shall be given for each container arrangement in cell guides: — — — — — — — —

container weight actual stack weights permissible stack weights transverse acceleration of each stack corner post loads pressure loads at bottom of container percentage of exceeding a warning has to be given if any of the strength limits are exceeded.

For bays with lashings applied and for bays with deck cell guides where containers will be overstowed on top, information shall be given for the following additional test conditions: — typical lashing arrangement and parameters — racking, lifting and lashing forces. 9.5.7 Test condition, load cases Test conditions shall be selected in order to represent typical container stowage as follows: — — — — —

typical stowage in hold mixed stowage in hold and/or on deck, if applicable typical stowage on deck deck stowage with twistlocks only an example where outboard stack is missing

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 54

Part 5 Chapter 2 Section 8

— negative weight input — container positioned outside the designated storage location — lashing which are not possible on board. The software and the stored characteristic data shall be protected against any erroneous use.

9.5.8 Test condition, acceptance criteria Results calculated by the software and shown in test conditions will be verified by the Society. The difference between the software and the verified results shall not be greater than 1%, as given in the following: [(Results from software) – (Results from independent calculations)]/(Strength limits) ≤ ±1% 9.5.9 Reference data In reference data, the following details shall be given: — — — —

main dimensions of the ship the position of each bay from the aft perpendicular strength limitations (for containers, lashing equipment and the ship) general loading limitations.

Reference data shall be included in test conditions or in a separate document.

9.6 Certification 9.6.1 General Certification shall be carried out for each ship where a lashing computer system has been installed. After completion of the test according to [9.6.2] the lashing computer certificate will be issued. The followings will be listed in the lashing computer certificate: — — — — — —

name of ship, name of yard, yard number and year of built for the ship software name, software version software manufacturer name and address hardware name, serial number and manufacturer name and serial number of the second nominated computer or type approval certificate number identification of the approved test conditions used for the certification.

9.6.2 Test The approved test conditions shall be tested on the lashing computer system on board of the ship in presence of the Society. During the test, — the securing arrangements calculated on the installed lashing computer system shall be verified to be identical to the approved test conditions. If numerical output from the lashing computer system is different with the approved test conditions, a certificate cannot be issued, and — at least one of the test conditions shall be built up from sketch, to ensure that the calculating methods function properly. Where the hardware is not type approved, the test shall be carried out on both the first and the second nominated computer prior to the issuance of the lashing computer certificate. Both of the nominated computers shall be identified on the certificate.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 55

Part 5 Chapter 2 Section 8

— other stowage as given in the approved container securing arrangements plan.

1 General 1.1 Objective This section contains specific requirements for hull support structures of container support fittings and container securing structures as given in Sec.8. This section is applicable for ships with hull support structures of container support fittings and container securing structures as given in Sec.8.

2 General requirements 2.1 Strength evaluation Hull support structures shall be provided for container support fittings and container securing structures as given in Sec.8. Strength evaluation of these structures shall be based on net scantlings.

2.2 Structure arrangement 2.2.1 The hatchway coamings shall be strengthened in way of the connections of transverse and longitudinal struts of cell guides. The cell guides shall not be welded to deck plating edges in way of the hatchways. 2.2.2 For containers stowed in cell guides in hold, doubler plates shall be arranged for the foot prints on inner bottom or stringers.

3 Design loads 3.1 General 3.1.1 Design loads of hull support structures shall be based on lashing/securing patterns as shown in the container stowage plan. 3.1.2 The hull support structures for lashing eye plates shall be strengthened with respect to the lashings' certified safe working loads (SWL). 3.1.3 For hull support structures subject to hull girder loads, such loads shall be included in the strength evaluation in accordance with [4] in addition to the design loads specified in this section.

3.2 Hull support structures for container support fittings 3.2.1 Design loads shall be calculated as reaction forces of container stacks acting on container support fittings under applicable load combinations listed in Table 1. Loads in design load combinations shall be calculated according to Sec.8 [6].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 56

Part 5 Chapter 2 Section 9

SECTION 9 HULL SUPPORT STRUCTURES FOR CONTAINER SUPPORT FITTINGS AND CONTAINER SECURING STRUCTURES

LC

Description

Vertical loads

Horizontal loads

Wind loads

1

Transverse loading

F

v1

Fq

Yes

2

Longitudinal/vertical loading

F

v2

Fl

No

3.3 Hull support structures for container securing structures Design loads acting on hull support structures shall be taken in accordance with Sec.8 [6].

4 Strength evaluation 4.1 General 4.1.1 Strength evaluation of hull support structures shall be based on load combinations according to [3] and acceptance criteria according to Sec.8 [7.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 57

Part 5 Chapter 2 Section 9

Table 1 Load combinations for hull support structures for container support fittings

1 General 1.1 Application 1.1.1 In conjunction to IACS UR W31 and IACS UR S33 this section shall be applied to ships with the class notation Container ship having thick steel plates with thickness exceeding 50 mm, but not greater than 100 mm, of steel strength groups VL 36, VL 40 and VL 47, for upper hull longitudinal structural members. The application of steel plates with thickness exceeding 100 mm shall be agreed on with the Society on a case-by-case basis. 1.1.2 The requirements given in [3] shall be applied additionally in cases where VL 47 material is applied according to [1.1.1]. 1.1.3 Upper hull longitudinal structural members include uppermost strake of longitudinal bulkhead, sheer strake, upper deck, hatch side coaming, and all attached longitudinals. See Figure 1 for illustrations.

Figure 1 Upper hull longitudinal structural members

2 Application of thick steel plates 2.1 General 2.1.1 This sub-section gives measures for identification and prevention of brittle fractures for ships according to [1.1.1]. 2.1.2 The application of the measures specified in [2.2] and [2.3] shall be according to [2.4] during construction.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 58

Part 5 Chapter 2 Section 10

SECTION 10 APPLICATION OF THICK STEEL PLATES AND ADDITIONAL REQUIREMENTS FOR STEEL STRENGTH GROUP VL47

2.1.4 The material grade selection shall be according to Pt.3 Ch.3 Sec.1 [2.3].

2.2 Brittle crack arrest design 2.2.1 Measures for prevention of brittle crack initiation and propagation, which is the same meaning as brittle crack arrest design, shall be implemented within the cargo hold region, see Table 1. 2.2.2 The approach given in this sub-section applies to the block-to-block joints, but it should be noted that cracks can initiate and propagate away from such joints. Therefore, appropriate measures shall be considered according to [2.2.4] (b). 2.2.3 Brittle crack arrest steel (BCA grade) is defined as steel plate with measured crack arrest properties according to Pt.2 Ch.2 Sec.2 [7] and applies in this scope to VL 36, VL 40 and VL 47 steels. 2.2.4 Functional requirements of brittle crack arrest design The purpose of the brittle crack arrest design shall arrest the propagation of a crack at a proper position and to prevent large scale fracture of the hull girder. The point of a brittle crack initiation shall be considered in the block butt joints both of hatch side coaming and upper deck. Guidance note: Butt weld joints designed to be in a straight line i.e. without a shift for the hatch coaming plate, the upper deck plate, the shear strake and the upper most strake of the longitudinal bulkhead are considered as block butt joints independent whether they are planned as assembly or sub assembly joints, see Figure 2. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Figure 2 Block butt joints Both of the following cases shall be considered: a) b)

where the brittle where the brittle where the brittle welds see Figure

crack may run straight along the butt joint, and crack initiates in the butt joint but deviates away from the weld and into the plate, or crack initiates from any other weld and propagates into the plate. For definition of other 3.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 59

Part 5 Chapter 2 Section 10

2.1.3 Welding procedures (WPS) shall be qualified through welding procedure qualification test (WPQT) according to Pt.2 Ch.4 Sec.5.

Part 5 Chapter 2 Section 10 Figure 3 Other weld items 1) 2) 3) 4) 5) 6) 7)

Fillet welds where hatch side coaming plating, including top plating, meets longitudinals. Fillet welds where hatch side coaming plating, including top plating and longitudinals, meets attachtments, e.g., where hatch side top plating meet hatch cover pad plating. Fillet welds where hatch side coaming top plating meets hatch side coaming plating. Fillet welds where hactch side coaming plating meets upper deck plaing. Fillet welds where upper deck plating meets inner hull/bulkheads. Fillet welds where upper deck plating meets longitudinal. Fillet welds where sheer strakes meets upper deck plating.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 60

Brittle crack arrest design for [2.2.4] b):

1)

Brittle crack arrest steel in upper deck plating, see [2.4] measure 4 and 5 Brittle crack arrest steel shall be used for the upper deck plating along the cargo hold region in a way suitable to arrest a brittle crack initiating from the coaming and propagating into the structure below.

Brittle crack arrest design for [2.2.4] a):

2)

High toughness welds and enhanced NDT, see [2.4] measure 2 Where high toughness welds are applied, as an equivalent alternative to 3), 4) and 5), enhanced NDT in accordance with [2.3], with stricter defect acceptance in lieu of standard UT technique shall be carried out. High toughness welds are defined as multi-pass welds with extended welding procedure qualification tests including CTOD tests. The CTOD tests shall be in accordance with Pt.2 Ch.1 Sec.3 based on modified minimum required target values of 0.2 mm for CGHAZ and WM. The CTOD is calculated as average of three valid CTOD test results, each individual value may not be less than 0.18 mm. For high toughness welds COD grade material in accordance with Pt.2 Ch.2 Sec.2 [8] shall be applied. Guidance note: Flux-cored arc welding (FCAW) is considered as high toughness welding for the coaming structure Table 1, while submerged arc welding (SAW) may be applied for upper deck and horizontal coaming plate butt weld joints. Electro gas welding (EGW) is not considered as high toughness welds. The CTOD tests required for high toughness welds can be carried out within the weldability tests (for material manufacturer approval) presumed that the same essential parameters for the welding procedure are applied. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3)

Block shift, see [2.4] measure 3 Where the block butt welds of the hatch side coaming and those of the upper deck are shifted, this shift shall not be less than 300 mm, see Figure 4. Brittle crack arrest steel shall be used for the hatch side coaming plating. The longitudinal weld joints from hatch side coaming to upper deck and from longitudinal bulkhead to upper deck, in vicinity of block joints, are important in brittle crack arrest design. Guidance note: Such longitudinal weld joints may be made as partial penetration welds with a root face of 50% of the abutting plate thickness, in vicinity of the block joints, between 300 mm aft and 300 mm forward in ship’s longitudinal direction, see Figure 4. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 61

Part 5 Chapter 2 Section 10

2.2.5 Concept examples of brittle crack arrest design The following options are considered to be acceptable ways of brittle crack arrest design. The detail design arrangements shall be submitted for approval. Other concept designs may be considered and accepted by the Society on a case by case basis.

4)

Crack arrest holes, see [2.4] measure 3 Where crack arrest holes are provided in way of the block butt welds at the region where hatch side coaming welds meets the deck welds, the fatigue strength of the lower end of the butt welds shall be assessed. Additional countermeasures shall be taken against brittle crack running away from the weld line into upper deck or hatch side coaming. These counter measures shall include the application of brittle crack arrest steel in hatch side coaming plating.

5)

Crack arrest insert plates, see [2.4] measure 3 Where insert plates of brittle crack arrest steel or weld metal inserts with high crack arrest toughness properties are provided in way of the block butt welds at the region where hatch side coaming welds meets the deck welds, additional countermeasures shall be taken against brittle crack running away from the weld line into upper deck or hatch side coaming. These countermeasures shall include the application of brittle crack arrest steel in hatch side coamings plating.

2.3 Non-destructive testing during construction 2.3.1 Where non-destructive testing (NDT) during construction is required according to [2.4], NDT shall be carried out according to Pt.2 Ch.4 Sec.7 and DNVGL-CG-0051, Non-destructive testing. In addition, where enhanced NDT as specified in [2.2.5] 2) is applied, enhanced NDT shall be carried out according to [4] and DNVGL-CG-0051, Non-destructive testing. 2.3.2 Target Joints NDT shall be carried out on all block-to-block butt joints of all upper hull longitudinal structural members as defined in [1.1.3].

2.4 Measures for thick steel plates The thickness and the steel strength group shown in the Table 1 apply to the hatch coaming structure, and are the controlling parameters for the application of countermeasures. In case of a thickness step the thicker plate shall be considered as the leading plate. If the as built thickness of the hatch coaming structure is less than the values given in Table 1, countermeasures are not required regardless of the thickness and steel strength group of the upper deck plating.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 62

Part 5 Chapter 2 Section 10

Figure 4 Block shift with partial penetration weld

Steel strength group

Thickness [mm]

Option

Measure 1

Measure 2

Measures 3+4

Measure 5

50 < t ≤ 85

-

N.A.

N.A.

N.A.

N.A.

85 < t ≤ 100

-

X

N.A.

N.A.

N.A.

VL 40

50 < t ≤ 85

-

X

N.A.

N.A.

N.A.

VL 40

85 < t ≤ 100

A

X

N.A.

X

X

B

X

X

N.A.

X

VL 40 (EGW)

85 < t ≤ 100

-

X

N.A.

X

X

VL 47

50 < t ≤ 100

A

X

N.A.

X

X

B

X

X

N.A.

X

-

X

N.A.

X

X

VL 36

VL 47 (EGW)

50 < t ≤ 100

Notes: 1)

X means to be applied

2)

N.A. means need not to be applied

3)

Either option A or B may be selected.

Measures: 1)

NDT other than visual inspection on all target block joints, see [2.3].

2)

Brittle crack arrest design against straight propagation of brittle crack along weld line by high toughness welds and enhanced NDT, see [2.2.5] 2).

3)

Brittle crack arrest design against straight propagation of brittle crack along weld line, see [2.2.5] 3), 4) or 5).

4)

Brittle crack arrest design against deviation of brittle crack from weld line, see [2.2.5] 1).

5)

Brittle crack arrest design against propagation of cracks from other weld areas, see Figure 3, such as fillets and attachment welds, see, [2.2.5] 1).

3 Additional requirements for steel strength group VL47 3.1 General 3.1.1 This sub-section gives requirements for ships according to [1.1.2], in addition to requirements specified in [2]. 3.1.2 VL 47 material shall not have lower grade then E.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 63

Part 5 Chapter 2 Section 10

Table 1 Measures depending on thickness and steel strength group of hatch coaming structures

3.2.1 Butt welded joints The butt welds in the hatch side coaming and in the upper deck shall be kept away from hatch corners as far as practical. Guidance note: The distance between such a butt weld to the termination point of the hatch corner curvature should be at least 500 mm in the ship's longitudinal and transverse directions respectively. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Butt welded joints in the hatch side coaming top plate shall be analysed to show sufficient fatigue life according to Sec.3. The stress concentration factor shall be calculated according to DNVGL-CG-0129 App.A Table 3. 3.2.2 Hatch corners Hatch corners in the hatch side coaming top plate and in the upper deck shall be analysed to show acceptable fatigue strength according to Sec.3, based on global FEA. 3.2.3 Grinding The free edge of hatch side coaming top plate shall not have any defects such as notches. The upper and lower edges of the hatch side coaming top plate in way of the butt welds and the hatch corners shall be ground smooth with a radius of 2 ~ 5 mm, see Figure 5. The grinding shall be done minimum 100mm forward and aft of the butt welds. For hatch corners, the grinding shall be applied to the whole hatch corner curvature and shall be extended to a point minimum 100mm away from the termination of the hatch corner curvature. Remaining upper and lower edges of the hatch side coaming top plate shall be ground smooth, with a radius of 2 mm as minimum. Butt welded joint edges at upper and lower sides of the hatch side coaming top plate shall be ground smooth. For longitudinals on the hatch side coaming top plate, the grinding shall be carried out similarly as described above.

Figure 5 Grinding of hatch side coaming top plate 3.2.4 Outfitting details To improve the fatigue life, outfitting details shall be applied as followings: a)

Welding for fixing outfitting to the hatch coaming top plate shall be avoided in the area close to hatch corner to the extent 500mm away from the termination of hatch corner curvature, in the ship’s longitudinal and transverse directions respectively. See Figure 6.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 64

Part 5 Chapter 2 Section 10

3.2 Fatigue

b) c)

Such a welding may be accepted, provided that the calculations based on global FE analysis according to Sec.3 show sufficient fatigue life at the weld toe on hatch coaming top plate. In such a case, weld profile shall be ground smooth with weld toe burr grinding according to DNVGL-CG-0129, Fatigue assessment of ships structures, or treated in alternative equivalent means accepted by the Society. For hatch cover pads welded to hatch coaming top plate, when the thickness of pads exceeds 25 mm, a chamfering of pads not exceeding 1:3 shall be applied in order to reduce the stress concentration on hatch coaming top plate. For weld connections of smaller outfitting such as holders to hatch side coaming, if the welding is in a rectangular or polygonal or similar shape where good workmanship is difficult to achieve in the corners, circular doubling plates shall be applied in order to achieve good workmanship. See Figure 7. The doubling plates shall be designed with a diameter, d, and a thickness, t, as small as practical, e.g., t ≤ 10 mm and d ≤ 150 mm. The minimum required material grade for these doubling plates is AH32. This material requirement may be waived, for round outfitting when d ≤ 50 mm and with welding in a circular shape on hatch side coaming, e.g., hand grip or hand rail stanchions, and for flat bar type attachments oriented in ship’s transverse or vertical direction.

Figure 6 Top plate of hatch coaming

Figure 7 Doubling plate for holders

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 65

Part 5 Chapter 2 Section 10

This may be achieved by applying flexible hatch cover pads without attachments to the hatch coaming top plate.

3.3.1 During construction stage, extent of NDT on welds of steel strength group VL 47 shall be at least as specified in Table 2. Table 2 Extent of NDT during construction stage Testing procedure

Weld type

Scope

Visual inspection (VT)

— all weld joints

100%

— transversely or vertically orientated weld joints including butt, T-joint and fillet welds

100%

Magnetic particle testing (MT)

— longitudinally orientated weld joints Ultrasonic testing (UT)

— full penetration weld joints including butt and T-joint

25% 100%

4 Enhanced non destructive testing of welds 4.1 Application 4.1.1 These rules shall be applied for welded joints for structural members in accordance with 2), see [2.2.5] 4.1.2 Prescribed reference level according to [4.3.5] shall be also valid for high strength hull structural steels with plate thicknesses exceeding 50 mm.

4.2 Magnetic particle testing procedure 4.2.1 Application This procedure describes the method for magnetic particle testing (MT) of fusion welded joints in material grade VL E47 and shall provide the minimum requirements, which should be carried out in order to maintain and control the weld quality. 4.2.2 Performance Magnetic particle testing of welded seams shall be performed according to DNVGL-CG-0051, Non-destructive testing. The acceptance criteria EN 1291 ISO 23278 level 1 shall be fulfilled. Therefore the detection of surface cracks with a linear length of 1.5 mm and a non-linear length of 2 mm has to be ensured. 4.2.3 Evaluation Every accumulation of magnetic particles not due to a false indication indicates a discontinuity or crack in the material which shall be registered in the inspection report and repaired. In the case of small cracks with length ≤ 3 mm this may be done by grinding. Larger cracks shall be machined out and repair welded. 4.2.4 Documentation The extend of the magnetic particle tested area and the test results shall be properly documented according to DNVGL-CG-0051, Non-destructive testing and in such a way that the performed testing can be retraced at a later stage.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 66

Part 5 Chapter 2 Section 10

3.3 Non-destructive testing

4.3.1 Application This procedure describes the method for manual ultrasonic testing (UT) of fusion welded joints in the upper hull with material grade VL E47 and thicknesses exceeding 50 mm and shall provide the minimum requirements, in order to maintain and control the weld quality in new building stage. 4.3.2 Objects to be tested 100% of the full penetrated butt welds in strength plates with thicknesses exceeding 50 mm. 4.3.3 Method Ultrasonic testing shall be performed with the impulse - echo technique by means of distance gain size – method (DGS). Phase array (PAUT) or time of flight diffraction (TOFD) testing methods may be applied instead of or in combination with DGS ultrasonic testing method. The related test and acceptance procedures have to be submitted to the Society for approval. 4.3.4 Requirement to the test equipment Ultrasonic gauge The used UT equipment has to fulfil the technical requirements as given in EN 12668-1, EN 12668-2 and EN 12668-3. The UT gauge has to be equipped with digital DGS- display presentation. The adjustment range for the display range shall enable the range from 1 mm up to 100 mm in even steps for longitudinal and transverse waves in steel. The amplification shall be adjustable for a range up to at least 80 dB with switching stages of 2 dB. Ultrasonic probes Probes to be used for ultrasonic testing shall be selected under consideration of nominal frequency, transducer size, size of disc- shape reflector to be tested, bevel preparation and sound attenuation of the material to be tested. For oblique scanning of the welded seams shear- wave probes with an angle of incidence of 45°, 60° or 70°, working with a nominal frequency of 2 MHz, shall be used. 4.3.5 Test class, requirements Test class B:

Acceptance ISO 11666 level 2 Reference flat bottom hole DDSR = 3 mm

Test method:

DGS- method

Table 3 Test classes Nominal probe frequency angle of incidence

Parent material thickness t [mm]

Reference flat bottom hole

2 MHz, 70° and 45° or 60°

50 ≤ t ≤ 100

DDSR = 3 mm

4.3.6 Performance of ultrasonic testing Sensitivity calibration The basic gain has to be increased by a certain number of dB, in respect to the sound path, taken out of a DGS-diagram for DDSR = 3 mm, belonging to the used brand of 70°-, 45°- respectively 60°-angle probe.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 67

Part 5 Chapter 2 Section 10

4.3 Ultrasonic testing procedure

Surface preparation Surface preparation shall be performed on both sides of the welded seam according to DNVGL-CG-0051, Non-destructive testing. Firmly adhering paint need not be removed provided that it does not interfere with the inspection and quantitative allowance. The loss of sensitivity has to be compensated by performing of transfer correction. Use of angle probes for the detection of longitudinal defects Testing for longitudinal defects has to be performed according to DNVGL-CG-0051, Non-destructive testing from both surfaces and both sides of the welded seam with two probes 70° and 45° or 70° and 60° depending on the bevel preparation. Use of angle probes for the detection of transverse defects Testing for transverse defects has to be performed according to DNVGL-CG-0051, Non-destructive testing from both surfaces and both sides of the welded seam with two probes 70° and 45° or 70° and 60° depending on the bevel preparation. Evaluation of defects a)

b) c)

d)

One characteristic which shall be stated for the classification of echo indications is by how many dB the maximum echo height of the reflections found differs from the registration level defined in Table 4 and mentioned X in Figure 9. In reference to the DGS- method, the size of the disc- shaped reflector may also be stated. Further characteristics to be stated are the depth of the defect as well as the registration length to be determined as given DNVGL-CG-0051, Non-destructive testing. The location of defects shall be defined by coordinates indicating the longitudinal and transverse distances from a reference point and the depth position too, see Figure 10. Echo indication produced by longitudinal defects which exceed the repair limit values shown in Table 4 (excess of registration length and/or echo heights above the registration level) shall be regarded as weld defects which have to be repaired. Indications which increase the evaluation level shall be observed as allowed and shall be calendared and documented in the test report. If the indication increase the reference level too, by maximum of 6 dB (max. permissible excess echo height) they are also treated as allowable and shall be documented too. Therefore the indication length has to be determined by the use of the 6dB- drop technique. Is the distance of two aligned indication less than the double length of the longer one, both indications can be treated as one indication. L1 < L2, ΔX1 < 2L2, L3 < L4, ΔX2 < 2L4, see Figure 10, but total length shall not exceed the maximum registration length shown in Table 4. However the minimum intermediate distance to the next indication has to be 40 mm.

Table 4 Repair limit values Longitudinal defects

Test class

B

Transversal defects

Plate thickness

Number of defects [nos./m]

Registration length

Max. permissible excess echo height

Number of defects [nos./m]

Registration length

Max. permissible excess echo height

[mm]

[m]

[mm]

[dB]

[m]

[mm]

[dB]

> 40

10 and 3 and

10 20

6 6

3

10

6

1

10

12

Documentation of the test results Ultrasonic test results shall be properly documented in such a way that the performed testing can be retraced at a later stage. All indications detected shall be reported in this context, regardless whether

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 68

Part 5 Chapter 2 Section 10

The correction value ΔVk for oblique scanning into the 100 mm radius of the calibration block has to be considered for each angle probe and can be seen in Figure 8.

a)

Clear identification of: — the component — the material — the welded joint inspected together with its dimensions and location (sketch to be provided for complex weld shapes and testing arrangements).

Figure 8 Correction value for oblique scanning (ΔVK)

Figure 9 DGS- Reference curve for DDSR = 3 mm

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 69

Part 5 Chapter 2 Section 10

these indications are exceeding the repair level or not. Repaired areas shall be re-tested and documented accordingly. The UT-report shall include a reference to the applicable standard and acceptance criteria too. In addition to the items listed under DNVGL-CG-0051, Non-destructive testing, the following shall be included in the ultrasonic testing report:

Part 5 Chapter 2 Section 10

Figure 10 Geometrical configuration of multiple indications

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 70

July 2016 edition

Amendments July 2017 • Sec.3 Loads — Sec.3 [2.3.2]: Correction factor for permissible hull girder shear force for harbour has been modified.

• Sec.5 Hull local scantlings — Sec.5 [2.1.4]: Clarification of minimum net thickness of non-tight transverse structures; change of wording has been made.

Main changes July 2016, entering into force as from date of publication • Sec.2 Structural design principles — [2] Materials deleted to align with UR S6.

• Sec.3 Loads — Sec.3 [2.2.3]: Corrected non linear factor from 1.1 to 1.0 in line with UR S11A. — Sec.3 [2.2.3]: Editorial correction, misprint corrected of parameter in formula. — Sec.3 [2.2.4]: Misprint corrected of parameter in formula, change of vertical shear force distribution (modified formulae and graphic) and adjustment of z-axis label.

• Sec.4 Hull girder strength — Sec.4 [2.6.2]: Limitation to hogging. — Sec.4 [2.6.2]: Link removed. — Sec.4 Figure 2: Misprint corrected.

• Sec.7 Fatigue — Sec.7 [1.1.2]: Prescriptive fatigue check shall be done for plates an stiffeners at transverse butt welds.

• Sec.8 Container securing arrangement — Sec.8 [1.1.2]: Clarification of rule text. — Sec.8 [4.4.2]: Missing minimum value of bℓ added.

• Sec.10 Application of thick steel plates and additional requirements for steel strength group VL47 — — — —

Sec.10 Sec.10 Sec.10 Sec.10

[2.2.3]: Editorial corrections in line with UR S33 Rev.1. [2.2.4]: Adding Figure 3 and explanations for "Other weld items" in line with UR S33 Rev. 1. [2.2.5]: Editorial wording addition in line with UR S33 Rev. 1. [2.3]: Link removed.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 71

Part 5 Chapter 2 Changes – historic

CHANGES – HISTORIC

Part 5 Chapter 2 Changes – historic

— Sec.10 Table 1: Link to new Figure 3 added in footnote 5).

January 2016 edition This document supersedes the October 2015 edition.

Amendments February 2016 • Changes - current page — Corrected section titles.

Main changes January 2016, entering into force 1 July 2016 • Sec.3 Loads — Implementation UR S11A.

• Sec.4 Hull girder strength — Implementation UR S11A.

• Sec.6 Finite element analysis — Implementation UR S34.

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.2. Edition January 2018 Container ships

DNV GL AS

Page 72

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition January 2018

Part 5 Ship types Chapter 3 RO/RO ships

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the July 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.3. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018. Topic Clarifications of Global FE procedure with respect to racking

Reference

Description

Sec.2 [1.2]

Required racking scope for ULS and FLS has been clarified for category I and II designs, reflecting the introduced simplified racking analysis and fatigue assessment valid for category I vessels based on ULS screening, and for category II vessels depending on the structural arrangement.

Sec.2 [3.2]

The dynamic load cases for racking, ultimate limit state (ULS) and fatigue limit state (FLS) has been updated, no longer referring to the beam sea roll (BSR) equivalent design wave (EDW). Hence: Sec.2 [3.2.2]: Rule transverse envelope acceleration, ay-env, to be applied for racking moment calculations. Sec.2 [3.2.3]: The new dynamic racking load cases may be based on hydrodynamic analysis to establish the racking design specific EDW targeting max transverse acceleration at top deck, or as an alternative and simplification use ay-env as target value for the hydrodynamic analysis. Sec.2 [3.2.4]: An alternative to hydrodynamic analysis, a racking load case based on ay-env and rule roll period may be applied without using a hydrodynamic software.

Sec.2 [5.2]

This sub-section describes the simplified racking analysis applicable to category I designs according to Sec.2 [1.2.1].

Sec.2 [8]

Sec.2 [8.1]: Describes that fatigue assessment by hot spot models (welded connections) or local models for free plate edges according to Sec.2 [8.3] applies in general for category II vessels. Sec.2 [8.5]: Describes the simplified fatigue analysis procedure required for category I vessels when nominal ULS stress range exceeds 100 MPa, and for category II vessels as an alternative method based on a case-by-case evaluation taking into account the structural arrangement of the racking constraining structure. This means that for RoPax vessels as a category II example, with structural redundancy with respect to racking constraining structure, this method may be applied.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 3

Part 5 Chapter 3 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................... 6 1 Introduction.........................................................................................6 1.1 Introduction..................................................................................... 6 1.2 Scope..............................................................................................6 1.3 Application....................................................................................... 6 2 Class notations.................................................................................... 6 2.1 Ship type notations.......................................................................... 6 2.2 Additional notations.......................................................................... 6 3 Definitions........................................................................................... 7 3.1 Terms..............................................................................................7 4 Documentation.....................................................................................7 4.1 Documentation requirements............................................................. 7 5 Product certificates..............................................................................8 5.1 Certification requirements.................................................................. 8 Section 2 Hull........................................................................................................ 10 1 Racking.............................................................................................. 10 1.1 General..........................................................................................10 1.2 Calculation scope for racking............................................................10 2 Docking.............................................................................................. 11 3 Loads................................................................................................. 11 3.1 Design still water bending moments..................................................11 3.2 Loads for global racking ULS- and FLS strength assessment................. 11 3.3 Loads for primary supporting members............................................. 13 4 Hull local scantling............................................................................ 15 4.1 Primary supporting members........................................................... 15 4.2 Securing points for lashing...............................................................18 4.3 Special strength considerations.........................................................19 5 Beam analysis....................................................................................20 5.1 Effective flange...............................................................................20 5.2 Simplified racking analysis............................................................... 20 5.3 Acceptance criteria..........................................................................20 6 FE analysis.........................................................................................21 6.1 General..........................................................................................21 6.2 Acceptance criteria..........................................................................21

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 4

Part 5 Chapter 3 Contents

CONTENTS

7.1 Side shell buckling for racking..........................................................22 7.2 Light car decks...............................................................................22 7.3 Pillars............................................................................................ 22 8 Fatigue strength................................................................................ 22 8.1 Application..................................................................................... 22 8.2 Prescriptive fatigue......................................................................... 22 8.3 Local FE analysis...........................................................................22 8.4 Fatigue damage calculations.............................................................23 8.5 Simplified fatigue analysis................................................................23 9 RO/RO equipment..............................................................................24 9.1 General..........................................................................................24 9.2 External vehicle ramps/ doors.......................................................... 24 9.3 Hoistable internal vehicle ramps/ ramp covers.................................... 24 9.4 Function test of RO/RO equipment.................................................... 25 Changes – historic................................................................................................ 26

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 5

Part 5 Chapter 3 Contents

7 Buckling............................................................................................. 22

1 Introduction 1.1 Introduction These rules apply to vessels intended for loading and unloading the cargo by Roll on/ Roll off (RO/RO), i.e. with class notations Car carrier or RO/RO ship.

1.2 Scope The rules in this chapter give requirements specific to RO/RO vessels.

1.3 Application The requirements in this chapter are supplementary to the rules in Pt.2, Pt.3 and Pt.4 applicable for the assignment of the main class. General reference is made to DNVGL-CG-0137 Strength analysis of hull structure in RO/RO vessels for general ship type information, design concepts and a description of acceptable approval procedures.

2 Class notations 2.1 Ship type notations Vessels built in compliance with the requirements as specified in Table 1 will be assigned the class notations as follows: Table 1 Ship type notations

Class notation

Description

Design requirements, rule reference

RO/RO Ship

Vessels intended for loading and unloading the cargo by Roll on/Roll off (RO/RO).

Sec.1 and Sec.2

Car Carrier

Vessels intended for carriage of vehicles.

Sec.1 and Sec.2

2.2 Additional notations The following additional notations, as specified in Table 2, are typically applied to RO/RO ships and car carriers: Table 2 Additional notations Class notation MCDK

Description Requirements for movable car decks.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Application All ships

Page 6

Part 5 Chapter 3 Section 1

SECTION 1 GENERAL

3.1 Terms Table 3 Definitions Terms

Racking constraining structure

Definition The structure that will constrain deflections in transverse direction Typical examples of racking constraining structures are engine room bulkheads, collision bulkhead, engine- and stairway casings and partial racking bulkheads/deep vertical web structure. Ramps, doors, hatch covers and movable decks and ramps for loading/ off-loading of RO/RO cargo or acting as cargo decks at sea, designed to:

RO/RO equipment

— load/off-load the ship’s cargo during port operations — function as cargo deck space where applicable, i.e. movable decks, ramp covers/inner ramps — function as watertight/weathertight boundary at sea where applicable, e.g. external doors/ramps, internal watertight hatches.

Uniformly distributed load (UDL)

2

Defined distributed design load for cargo decks given in t/m , representing the maximum distributed load for a deck or part of a deck.

4 Documentation 4.1 Documentation requirements General requirements for documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.1. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 7

Part 5 Chapter 3 Section 1

3 Definitions

Object

Ship hull structure

Cargo securing arrangement

Documentation type

Additional description

Info

H081 - Global strength analysis

When required by Sec.2 [1.2].

FI

H085 - Fatigue analysis

When required by Sec.2 [1.2].

FI

H050 - Structural drawing

Connections between door frames and bulkheads in racking constraining structure.

AP

Z030 - Arrangement drawing

— securing points for lashing with data regarding position, type, design of fittings and maximum securing load (MSL) — stowage and securing arrangement for all vehicles to be carried

FI

— maximum axle load and number of axles of vehicles. — car deck pontoons and their weights Z030 - Arrangement drawing Movable car deck arrangements H050 - Structural drawing

— stowing arrangement for deck pontoons not in use. This should include all stressed strength members, such as racks on deck, securing devices, reinforcement of supporting hull structures, etc. — supports or suspensions — connections to hull structure with information regarding reaction forces from hoisting devices.

Z253 - Test procedure for quay and sea trial Internal movable ramps H050 - Structural drawing

FI

AP

FI — Including design loads and maximum reaction loads in supporting structure.

AP

AP = For approval; FI = For information

5 Product certificates 5.1 Certification requirements For products that shall be installed on board, the builder shall request the manufacturers to order certification as described in Table 5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 8

Part 5 Chapter 3 Section 1

Table 4 Documentation requirements

Object

Certificate type

Cargo securing devices, fixed

PC

Cargo securing devices, portable

PC

Issued by

Certification standard

Society

DNVGL-CP-0068 Certification of container securing devices

Additional description

If certification by the Society, DNVGL-CP-0068 Certification of container securing devices

For general certification requirements, see Pt.1 Ch.3 Sec.4. For a definition of the certificate types, see Pt.1 Ch.3 Sec.5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 9

Part 5 Chapter 3 Section 1

Table 5 Certification requirements

1 Racking 1.1 General A racking strength assessment shall be carried out following the requirements given in this sub-section. Special attention shall be given to the connections between transverse structural members to the bulkhead deck or the uppermost deck level with high racking rigidity. Intersections between horizontal and transverse members shall be assessed in areas subjected to high racking deformations, i.e. response caused by roll motion acting on the cargo at multiple decks combined with selfweight of structure and equipment.

1.2 Calculation scope for racking 1.2.1 General The transverse strength shall be checked against: 1) 2)

the ultimate limit state (ULS) under extreme loading the fatigue limit state (FLS) under variable cyclic loading.

The extent of the calculation scope depends on the vessel’s arrangement and complexity. Two categories, based on structural configuration, are used to group the scope and the calculation requirements for ULS and FLS: Category I, designs with: — not more than two RO/RO decks above bulkhead deck and — evenly distributed self-supporting side web frames, e.g. frames able to restrain the racking response from all decks based on given frame spacing. Category II, designs with: — multiple decks and few effective transverse strength members such as engine casing box, stair casing box and deep racking frames/ bulkheads. 1.2.2 Scope of racking calculations for category I vessels Transverse strength is provided by deep vertical web frames in the ship’s side and/or transverse bulkheads in the accommodation area. A simplified racking assessment method as described in [5.2] will be accepted for the evaluation of the adequacy of the transverse strength for the ULS scope. A simplified FLS assessment according to [8.5] may be required depending on the nominal ULS stress range level. 1.2.3 Scope of racking calculations for category II vessels A global FE strength analysis is required to document the racking response and to demonstrate that the stresses are acceptable under ULS load conditions. Acceptable analysis methods and criteria are given inDNVGL-CG-0137 Sec.5 and [6.2], respectively. Supporting documentation for the direct strength analysis is described in DNVGL-CG-0127 Sec.2. A separate FLS analysis shall be carried out according to [8]. For vessels with length L < 120 m, a reduced calculation scope according to [1.2.2] may be accepted on a case-by-case basis.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 10

Part 5 Chapter 3 Section 2

SECTION 2 HULL

For large RO/RO ships and car carriers that may have large docking weight, special strength calculation of the bottom structure in way of the docking blocks may be required. Reference is made to the rules Pt.3 Ch.3 Sec.5 [3.4] regarding requirements for docking. Acceptance criteria for direct docking analysis for beam- or FE analysis, shall be taken according to: — beam analysis: Pt.3 Ch.6 Sec.6 [2.2], AC-I — FE analysis: Pt.3 Ch.7 Sec.3 Table 1, AC-I.

3 Loads 3.1 Design still water bending moments The still water bending moment limits shall be based on an extreme non-homogenous loading condition. For the hogging limit, an increased load density shall be assumed in the aft ship and fore ship area. Guidance note: Based on a homogeneous loading condition on scantling draught, 25% of the load within 0.4 L should be redistributed equally to the load area aft of 0.3 L and forward of 0.7 L, without exceeding the maximum specified uniformed distributed load (UDL) for the heavy RO/RO decks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

A sagging still water bending moment limit value lower than the minimum rule sagging moment may be accepted, provided this can be documented. A negative still water sagging limit (i.e. minimum hogging) may be accepted provided that it can be demonstrated that the vessel will not experience static sagging. In such case, an extreme but realistic still water sagging condition with increased load density within 0.4 L and decreased load density outside 0.4 L, shall be taken into account. Guidance note: Based on a homogeneous loading condition on scantling draught, load density within 0.4 L should be increased with 25%, without exceeding the maximum specified uniformed distributed load (UDL) for the heavy RO/RO decks. Increased load density within 0.4 L shall be compensated by reduction of load density aft of 0.3 L and fwd of 0.7 L to obtain the same cargo deadweight. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2 Loads for global racking ULS- and FLS strength assessment 3.2.1 Loading condition for racking The loading condition, which results in the maximum racking moment about the bulkhead deck, shall be chosen for the ULS transverse strength analysis. The racking moment shall be calculated according to [3.2.2]. For FLS transverse strength analysis, the most frequent loading condition should be chosen. Guidance note: The loading conditions evaluated should be taken from the loading manual. To simplify the design process, the same loading conditions as for ULS may be applied for the FLS assessment, even if it could be somewhat conservative. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: It should be noted that lower GM values used in the fatigue life assessment, results in overestimated fatigue life. The GM value representative for the departure condition should therefore be used as basis for the fatigue analysis. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 11

Part 5 Chapter 3 Section 2

2 Docking

mc,i ms,i ay,i zi zmain

= mass on deck number i = self weight of deck number i = transverse acceleration at deck number i for the dynamic load cases specified in [3.2.3] = vertical distance above base line for deck number i = vertical position above base line for bulkhead deck.

If the maximum allowable cargo mass has been assumed for the heavy cargo decks, movable cargo decks installed directly above such decks should be assumed empty and in the stowed position. If the design draught is not reached for a given loading condition, lower decks shall be assumed loaded until design draught is reached. Guidance note: A high racking moment is achieved if the load is located on the upper decks. However this results in lower GM values and thus also lower transverse accelerations which will reduce the racking moment. Hence, racking moment calculations should be carried out for most of the loading conditions from the loading manual. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2.3 Racking load cases using direct hydrodynamic analysis The design wave load cases which shall be used to evaluate the transverse strength of the ship structure are the load cases, heeling both sides, which maximizes the transverse acceleration at upper deck level, including gravity components. The load cases should be established for 25 years return period, North Atlantic environmental scatter, using a recognized wave load software. Alternatively, ay-env according to Pt.3 Ch.4 Sec.3 [3.3.2] at upper deck level, may be applied as target value in order to establish the dynamic load case for racking analysis from direct hydrodynamic analysis. Acceptable procedures for the methods described above are given in DNVGL-CG-0137 Sec.5 [2.2]. 3.2.4 Racking load cases without direct hydrodynamic analysis Inertia loads for cargo load and selfweight on all decks above bulkhead deck based on: (1)

ay az

= ay-env according to Pt.3 Ch.4 Sec.3 [3.3.2]. For FLS analysis, fp factor to be included = g (gravity).

(1)

When FLS assessment is based on ULS screening as described in [8.1], fp is not applicable.

Hydrostatic sea pressure based on roll angle,

ϴ, as defined in Pt.3 Ch.4 Sec.3 [2.1.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 12

Part 5 Chapter 3 Section 2

3.2.2 Racking moment calculation The racking moment is calculated using both cargo weight (mc) and the self weight (ms). For unloaded weather decks, if no deck load is specified, it is sufficient to include the load corresponding to the self-weight, including the self-weight of accommodation- and garage deck. Movable car decks shall be included as point loads in way of support positions. The transverse force on each deck level is obtained as the total mass times the transverse envelope acceleration according to Pt.3 Ch.4 Sec.3 [3.3.2]. The acceleration shall be based on the GM value for the actual loading condition, but shall not be taken less than 0.05 B for ULS and 0.035 B for FLS. Thus, the racking moment, MR, to be estimated as:

3.3.1 Design load sets for prescriptive rule check Design load sets and load combinations of static and dynamic loads for tank and watertight boundary structure, external shell envelope structure e.g. bottom structure, side shell primary supporting members (PSM) and deck structure, are given in Pt.3 Ch.6 Sec.2 Table 2. 3.3.2 Loading patterns for direct analysis The load patterns for upright conditions described in Table 1 shall be assessed to ensure that the PSM's have sufficient strength.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 13

Part 5 Chapter 3 Section 2

3.3 Loads for primary supporting members

1)

Load pattern

Description

Draught

Strength members

LC 1

Normal ballast draught with no cargo

TBAL

Bottom structure

LC 2

Maximum uniform cargo on lower decks until TSC is reached

TSC

Lower cargo decks

LC 3

Maximum uniform cargo on upper decks until TSC is reached

TSC

Upper cargo decks

LC 4

Transversely unsymmetrical deck loads

TSC

Transverse deck girders at midspan

LC 5

Longitudinally unsymmetrical deck loads

TSC

Longitudinal deck girders at midspan

2)

Heavy cargo unit (e.g. MAFI) on single girder

TSC

Transverse and longitudinal girders

3)

Flooded condition

TDAM

Transverse and longitudinal girders

LC 6 LC 7 1)

Self weight shall be included.

2)

Special load case to evaluate strength of individual strength members under heavy cargo units. Load distribution/ combination shall be based on information from a cargo stowage plan, see DNVGL-CG-0137 Strength analysis of hull structure in RO/RO vessels.

3)

No cargo load on the watertight deck shall be applied, only selfweight.

3.3.3 Design load sets for beam analysis Relevant design load sets described in Pt.3 Ch.6 Sec.2 Table 2 and Pt.3 Ch.6 Sec.8 Table 1 shall be applied to the model. For internal decks, the UDL design load sets applies and the Pdl-d may be based on envelope acceleration according to Pt.3 Ch.4 Sec.3 [3.3]. The following design load sets apply: a)

UDL-1h: (Pdl-s + Pdl-d) combined with maximum hull girder vertical bending moment in hogging,

b)

i.e. Mwv-h + Msw-h based on HSM-2 UDL-1s: (Pdl-s + Pdl-d) combined with maximum hull girder vertical bending moment in sagging, i.e. Mwv-s + Msw-s based on HSM-1

Optionally, the accelerations for the considered dynamic load case may be applied. This results in twice the number of load sets, maximizing both local pressure and hull girder vertical bending moment, as described in Pt.3 Ch.6 Sec.2 Table 2. 3.3.4 Load combinations for partial ship FE analysis Table 1 in combination with Table 2 provide design loads for partial ship finite element analysis.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 14

Part 5 Chapter 3 Section 2

Table 1 Load patterns for upright conditions

Loading pattern

Structural members 1) to be assessed

LC1

Double bottom structure

LC2

Lower cargo decks Upper cargo decks

LC3

Dynamic load cases 2)

FSM-1/2

HSM-1 and HSM-2

Accelerations on cargo

Draught

NA

TBAL

az-env

Acceptance criteria

TSC 3)

2)

Double bottom structure

FSM-1/2

LC4

Transverse girder at midspan

LC5

Longitudinal girder at midspan

LC6

Heavy cargo decks

HSM-2

LC7

Watertight decks

NA

HSM-1 and HSM-2

az(FSM-2)

TSC

az-env

TSC

NA

TDAM

AC-II

AC-III

1)

The assessment shall also cover connection to other PSM's, such as side web frames and pillars

2)

FSM-1 applies aft of 0.3L from AE. For cargo area forward of 0.3L from AE, FSM-2 applies

3)

The maximum draught given in the trim and stability booklet may be used, see DNVGL-CG-0137 Sec.4 [1.8], but the draught shall not be less than 0.9TSC.

az-env az(FSM-2)

= as defined in Pt.3 Ch.4 Sec.3 [3.3.3] = vertical acceleration at any point as defined in Pt.3 Ch.4 Sec.3 [3.2.3] for FSM-2.

Guidance note: LC1 assessment of double bottom area is normally only applicable from aft of 0.2L from FE, from where the cargo area on inner bottom terminates and the bottom girder grill becomes limited. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.3.5 Load combinations for global FE analysis For designs where global FE racking assessment is required according to [1.2], the global analysis may be used for a complete strength assessment of PSM's. The analysis shall cover the load patterns, LC1 to LC5, defined in Table 1 and these shall be combined with the dynamic load cases described in Pt.3 Ch.4 Sec.2. 3.3.6 Cargo loading In addition to the UDL as given by the designer, the deck girder structure shall be checked for the most severe combination of axle(s) positioning of cargo handling vehicles in harbour and for vehicles as cargo in seagoing conditions.

4 Hull local scantling 4.1 Primary supporting members 4.1.1 Pillars The pillars shall be fitted in the same vertical line, from bottom to upper most deck. If not possible, the pillars shall be effectively supported by box girder or bulkhead structures, and direct strength analysis will be required.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 15

Part 5 Chapter 3 Section 2

Table 2 Load input for FE analysis

4.1.3 Modelling and strength of cross-joints The flange discontinuity at cross joints of highly stressed girders may be compensated for by brackets. If the fitting of such brackets is not possible (e.g. between deck transverse and ship side vertical girders), high shear stresses in the web area that combines the girders may be the consequence. This is illustrated in Figure 2. 2

As an alternative to Pt.3 Ch.3 Sec.6 [3.4.4], the mean shear stress in N/mm may be derived directly as follows:

and where:

FSi PFi Di tw-gr_off

= shear force in girder in N = flange force in girder in N = web thickness of girder in mm = gross offered thickness of web plate of cross-joint in mm.

For racking conditions, shear force, FS1/2, might give a positive contribution to the total shear force, hence – shall be replaced with + if applicable. For evaluation of T-joint, the flange force PF shall be taken as the sum of the flange forces of adjoining girders. Similarly, the shear force FS shall be taken as the sum of the shear forces (absolute value) of the adjoining girder webs (see Figure 2):

In case the shear stresses are taken from a finite element analysis, the average shear stress of the elements within the cross joint may be applied and compared against allowable stresses. The allowable shear stress of the web plate shall be taken in accordance with Pt.3 Ch.3 Sec.6 [2.2] The welding of the web plate of cross joints shall be based on Pt.3 Ch.13 Sec.1. The flange thicknesses of non-bracketed cross joints shall not be less than half of the required web plating thickness of the cross joint. The shear flexibility of the web plates within girder cross joints gives rise to rotational deformation of the transverse deck girders relative to the vertical girders of the ship side. This flexibility in the beam model may be represented as a rotational spring between the deck girder element and the vertical web frame, see Figure 3. The spring stiffness KRC in Nmm/rad may be determined as:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 16

Part 5 Chapter 3 Section 2

4.1.2 Slenderness of primary support members Where a primary structure member is intended mainly for interfacing structure of RO/RO equipment and not contributing to major structural strength, e.g. a stringer in superstructure side for movable car deck, a slenderness coefficient Cw = 125 shall be applied for the web plate requirement given in Pt.3 Ch.8 Sec.2 [4.1.1].

h1, h2, tw-gr_off G

= as given in Figure 1 in mm 5

Part 5 Chapter 3 Section 2

where: 2

= shear modulus, 0.7×10 N/mm (steel).

Figure 1 Geometry cross joint

Figure 2 Analysis of cross joint

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 17

Part 5 Chapter 3 Section 2 Figure 3 Spring representation of deck and side girder cross joint

4.2 Securing points for lashing 4.2.1 General Decks intended for carriage of vehicles shall be equipped with a satisfactory number of securing points (cargo securing device) for lashing of the vehicles. The arrangement of securing is left to the discretion of the owner, provided the minimum requirements in [4.2.2] through [4.2.6] are satisfied. 4.2.2 Scantling Stiffeners and girders are subject to direct analysis according to Pt.3 Ch.6 Sec.5 [1.2] and Pt.3 Ch.6 Sec.6 [2.2], respectively, applying the maximum securing load defined in [4.2.3] to [4.2.6]. βs,

αs and Cs-max may be taken as for acceptance criteria AC-II.

4.2.3 Maximum securing load Unless otherwise specified, each lashing point shall have a maximum securing load (MSL) of not less than:

MSL = k Q g 0 max, 0.5 Pm min, 100 kN in decks for heavy cargo, e.g. busses, road- and MAFI trailers min, 15 kN in decks for cars only.

k

= n/r If r is different from 1, k shall be increased by 10%

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 18

= minimum breaking load of the considered cargo securing device = number of effective lashing points at each side of the vehicle for the number n of axles in group = the maximum axle load given in tons. For MAFI road trailers, Q may be calculated as the total weight with n = 1 and r = the total number of lashings at each side.

4.2.4 More than one lashing If the securing point is designed to accommodate more than one lashing, the magnitude and direction of the lashing loads shall be taken into account when determining the total MSL of the securing point. 4.2.5 MSL less or equal to 15 kN Lashing points intended for a maximum working load of 15 kN can normally be arranged without any strengthening of the deck plating. 4.2.6 MSL more than 15 kN The strength of lashing points intended for a maximum working load of more than 15 kN shall be documented by either structural analysis or mock-up tests.

4.3 Special strength considerations 4.3.1 2-stack MAFI trailers Strength of decks intended for carrying MAFI trailers or other vehicles carrying more than one tier of containers shall be checked for possible tension loads and increased vertical compression load due to rolling. Additional load cases shall be included in beam- or FE analysis. 4.3.2 Door openings in racking constraining structure In case of door openings in racking constraining structure, especially transverse structure, it is important to provide radius in the corners to obtain acceptable local stresses in the corners. Rectangular door frames without radius shall not be welded directly to the bulkhead plate. It is recommended to introduce recess structure in order to avoid unnecessary stress concentrations in way of the door frame. 4.3.3 Deck openings in way of ramps/ ramp covers Special consideration is required for girder structure forming the framing around deck ramp openings. Direct strength analysis shall be used to demonstrate that rule requirements are satisfied. 4.3.4 Watertight integrity of trunks Where a ventilation trunk passing through a structure penetrates the bulkhead deck, the trunk shall be capable of withstanding the water pressure that may be present within the trunk, after having taken into account the maximum heel angle allowable during intermediate stages of flooding, in accordance with SOLAS Ch. II-1/8.5. Where all or part of the penetration of the bulkhead deck is on the main ro-ro deck, the trunk shall be capable of withstanding impact pressure due to internal water motions (sloshing) of water trapped on the roro deck. 4.3.5 Flexible hinge member The longitudinal flexible hinge in the hinged deck design car carriers shall have low torsional stiffness (i.e. flat bar is preferred) and the distance between the flexible hinge and the face plate of the side girder should be made as small as possible, see DNVGL-CG-0137 Sec.1 Figure 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 19

Part 5 Chapter 3 Section 2

Pm r Q

5.1 Effective flange Effective breadth, beff or beff*, for the PSM of attached plating should be calculated according to Pt.3 Ch.3 Sec.7 [1.3.2]. The effective breadths, be, in mm, of the plate- and the free flanges of transverse deck girders and vertical side girders in way of deck- and side girder cross joints shall not be taken larger than:

beff*

= 1.15hs + khd for deck girders = 1.15hd + khs for side girders

beff*-max = b = web height of side girder in mm hs = web height of deck girder in mm hd = 0.25 for plate flanges k = 0 for free flanges

b

= flange (free flange or plate flange) with in mm.

5.2 Simplified racking analysis 5.2.1 Application For category I designs according to [1.2.1], a simplified racking assessment using beam or FE- model may be carried out. 5.2.2 Modelling The PSM's above bulkhead shall be modelled with beam elements applying effective flange according to [5.1]. 5.2.3 Boundary conditions Fixed in all freedoms of translation at bulkhead deck. 5.2.4 Dynamic loads Transverse = (UDL + selfweight) x ay-env

Vertical

= (UDL + selfweight) x g

5.3 Acceptance criteria 5.3.1 Yield criteria for upright conditions Acceptance criteria for yield are given in Pt.3 Ch.6 Sec.6 [2.2.2]. 5.3.2 Yield criteria for racking ULS acceptance criteria as defined in [6.2] applies in general. For fatigue critical details, e.g. web stiffened cruciformed joints in way of ship side and pillars, screening procedure according to DNVGL-CG-0137 Sec.8 [2] applies. 5.3.3 Buckling criteria Acceptance criteria for buckling are given in Pt.3 Ch.6 Sec.6 [2.2.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 20

Part 5 Chapter 3 Section 2

5 Beam analysis

6.1 General Reference is made to Pt.3 Ch.7 Sec.4, supporting DNVGL-CG-0127 Finite element analysis and DNVGLCG-0137 Strength analysis of hull structure in RO/RO vessels, for FE model procedures.

6.2 Acceptance criteria 6.2.1 Yield criteria for upright conditions Acceptance criteria for yield strength assessment of PSM's based on partial ship structural FE analysis is given in Pt.3 Ch.7 Sec.3 [4.2]. 6.2.2 Yield criteria for racking ULS Stresses in plating of transverse racking constraining structure shall not exceed the permissible values given in Table 3: Table 3 Permissible stresses for global finite element analysis

(1)

Normal membrane (1) stress

Shear stress

Von Mises stress

200/k

120/k

220/k

Axial stress for face plates of PSM's modelled with beam elements.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 21

Part 5 Chapter 3 Section 2

6 FE analysis

7.1 Side shell buckling for racking Panel buckling assessment of ship side in way of racking constraining structure, such as racking casings/ boxes, shall be carried out.

7.2 Light car decks Buckling assessment of light car decks shall be performed according to Pt.3 Ch.3 Sec.7 [1.3].

7.3 Pillars 7.3.1 General Buckling strength of pillars shall be assessed according to Pt.3 Ch.8 Sec.4 [5] and DNVGL-CG-0128 Sec.3 [4]. 7.3.2 Buckling load The actual compression stress in the pillar shall be calculated by summarizing the accumulated forces based on maximum design loads of all the decks above the pillar in question. 7.3.3 Acceptance criteria for buckling Acceptance criteria for pillar buckling is given in Pt.3 Ch.8 Sec.1 [3.4].

8 Fatigue strength 8.1 Application A prescriptive fatigue check according to [8.2] is mandatory for all vessels with L > 150 m. Fatigue assessment by hot spot models (welded connections) or local models for free plate edges according to [8.3] applies in general for category II vessels, defined in [1.2.1].

8.2 Prescriptive fatigue Local structure that shall be assessed by the prescriptive fatigue method, according to Pt.3 Ch.9 are the end connections of longitudinal stiffeners in outer shell below freeboard deck. Relative deflections and double hull bending may be ignored.

8.3 Local FE analysis 8.3.1 Application With reference to Pt.3 Ch.9 Sec.3 [4], standard critical details, defined in [8.3.2], shall be assessed by hot spot fatigue analysis. Local models shall be made according to Pt.3 Ch.7 Sec.4. Fatigue assessment for other details will be required on a case by case basis, determined based on the nominal stress level from the global ULS analysis. Example of such details are given in [8.3.3]. 8.3.2 Standard critical details Connection of main racking constraining structure to bulkhead deck, typically: — engine room casing

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 22

Part 5 Chapter 3 Section 2

7 Buckling

8.3.3 Other critical areas Other critical areas with respect to fatigue are represented by typical details in way of: — connection between transverse deck girders and racking constraining structure such as casings and/ or racking boxes — connections of vertical web frames to bulkhead deck — connection between vertical side frames and transverse deck girders — connection between pillars and transverse deck girders — pillar connection to top deck and inner bottom — other rigid structure, such as staircase or ventilation ducts and their connection to PSM’s — vertical side frames connection to collision bulkhead — crossing flange connections between transverse deck frames and longitudinal deck girders.

8.4 Fatigue damage calculations 8.4.1 Zero-crossing frequency The zero-crossing frequency for the roll response shall be taken as:

when calculating the fatigue damage accumulation according to DNVGL-CG-0129 Sec.3. 8.4.2 Stress range With reference to DNVGL-CG-0129 Sec.3 [2.5], the stress range Δσ needed for the fatigue damage evaluation shall be calculated as:

where, — Δσ = Hot spot stress range for racking — σHS-P = Hot spot stress for heeling to portside — σHS-S = Hot spot stress for heeling to starboard.

8.5 Simplified fatigue analysis 8.5.1 Application Applicable to category I vessels when nominal ULS stress range exceeds 100 MPa, and to category II vessels as an alternative method based on a case-by-case evaluation taking into account the structural arrangement of the racking constraining structure. 8.5.2 ULS screening The following simplified method supported by DNVGL-CG-0129 may be applied in order to establish the maximum allowable ULS stress range with respect to fatigue: 1) 2) 3)

Calculate the corresponding Weibull shape parameter for roll motion, ξ* = Log10(0.25)/Log10(fp), where fp is to be calculated according to Pt.3 Ch.4 Sec.3 [2.2.4] for fatigue assessment. Calculate zero-crossing frequency, see [8.4.1]. Calculate number of cycles, ND, for the lifetime (25 years), see DNVGL-CG-0137 Sec.8 [1.6].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 23

Part 5 Chapter 3 Section 2

— stairway/lift casings, if continuous up to weather deck — deep racking frames — partial bulkheads.

Find the permissible stress range, ∆σFS, at 10 probability level by interpolation of the values given in DNVGL-CG-0129 App.C Table 4 based on the Weibull shape parameter ξ* and the stress cycles, ND, calculated above.

5)

Calculate allowable nominal stress range,

Kg

-8

∆σnom = ∆σFS/ (Kg*fmean*fthick*fe).

= Value to be selected for appropriate detail as given in DNVGL-CG-0129 Appendix A

The other factors are given in DNVGL-CG-0137 Sec.8.

9 RO/RO equipment 9.1 General 9.1.1 Introduction RO/RO equipment shall satisfy the requirements in this section in addition to general requirements for shell doors and ramps given in Pt.3 Ch.12 Sec.5 and internal doors/hatches as given in Pt.3 Ch.12 Sec.3. 9.1.2 Local scantling Requirements for plate and stiffener are given in Pt.3 Ch.6 Sec.4 and Pt.3 Ch.6 Sec.5, respectively. Decks and ramps subject to wheel loading shall comply with requirements in Pt.3 Ch.10 Sec.5 under port operations and at sea. Minimum thicknesses are given in Pt.3 Ch.6 Sec.3. Guidance note: It is particularly important that all vehicle information is available, together with footprint data and axle arrangements since these are the main parameters to determine the design loads for the plating and stiffeners. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Scantlings of decks, ramps, lifts etc. for railway carriages will be specially considered in each case. 9.1.3 Damage condition The maximum deflection of the ramp/ramp cover edge under damage condition shall be carefully examined and documented, in order to ensure watertightness.

9.2 External vehicle ramps/ doors 9.2.1 General Requirements for side- or stern doors and bow doors are given in Pt.3 Ch.12 Sec.5 [1] and Pt.3 Ch.12 Sec.5 [2], respectively. Requirements for cargo hatches on exposed decks are given in Pt.3 Ch.12 Sec.4.

9.3 Hoistable internal vehicle ramps/ ramp covers 9.3.1 General For internal ramp covers, requirements in Pt.3 Ch.12 Sec.3 apply. 9.3.2 Loads at sea If the ramp/ramp cover is acting as a watertight deck opening cover, it shall be designed against the deepest damage waterline according to Pt.3 Ch.12 Sec.3 [4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 24

Part 5 Chapter 3 Section 2

4)

— bending stress (normal membrane stress)= 0.85 ReH — shear stress= 0.85 τeH — von Mises stress (for FE only) = 0.9 ReH. The design loads including dynamic factors shall be specified by the designer. Guidance note: Acceptance criteria AC-II is applied, since the lifting operation is considered as a dynamic load case. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: Requirements related to the hoisting equipment as a lifting appliance are covered by separate standards. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9.4 Function test of RO/RO equipment Every RO/RO equipment item shall be function tested to demonstrate that all expected operations are functioning properly. Load testing as part of function testing is required for RO/RO equipment which is lifted with cargo. The test load shall be the maximum design load of the equipment. Testing and certification requirements according to DNVGL-ST-0377 Standard for shipboard lifting appliances is required if the ILO 152 certificate shall be issued by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 25

Part 5 Chapter 3 Section 2

9.3.3 Ramps hoisting with cargo in harbour condition For ramps hoisted with cargo, the stress level in the PSM's shall fulfill the following acceptance criteria, AC-II, based on the maximum design loads, including dynamic factors:

July 2017 edition

Changes July 2017, entering into force 1 January 2018. Topic

Reference

Allowable stress, Sec.2 [9.3.3] hoistable internal ramps.

Description Specified allowable stresses for hoistable internal ramps when hoisted with cargo.

July 2016 edition

Main changes July 2016, entering into force as from date of publication • Sec.2 Hull — Sec.2 Table 2: Modified FE load case.

January 2016 edition This document supersedes the October 2015 edition.

Main changes January 2016, entering into force as from date of publication • Sec.2 Hull — — — —

[3.3.3]: Design load sets for beam analysis (PSM) defined [3.3.4]: Load combinations for partial ship FE analysis (PSM) defined [4.1.4]: Modelling and strength of cross-joints included [7]: Buckling ship type requirements included for side shell in racking condition, light car decks and pillars

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.3. Edition January 2018 RO/RO ships

DNV GL AS

Page 26

Part 5 Chapter 3 Changes – historic

CHANGES – HISTORIC

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition January 2018

Part 5 Ship types Chapter 4 Passenger ships

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the January 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.4. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018. Topic Clarifications of Global FE procedure with respect to racking

Reference Sec.2 [2.2.2]

Description The dynamic load cases for racking, ultimate limit state (ULS), has been updated, no longer referring to the beam sea roll (BSR) equivalent design wave (EDW). The new dynamic racking load cases shall either be based on hydrodynamic analysis to establish the racking design specific EDW targeting max transverse acceleration at top deck, or as an alternative and simplification use ay-env as target value for the hydrodynamic analysis.

Sec.2 [2.2.3]

For designs with evenly distributed racking constraining structure, ay-env may be applied directly on all decks above bulkhead deck, without any hydrodynamic analysis.

Clarifications of Global FE procedure with respect to racking

Sec.2 [4.1]

Sec.2 [4.1.2] describes the boundary conditions for transverse strength assessment when the loads are either based on direct dynamic loads (Sec.2 [2.2.2]) or rule ay-env accelerations (Sec.2 [2.2.3]).

Balcony door and supporting frames

Sec.2 [6.2]

Design pressure for which the balcony door and its supporting frames shall withstand is defined, together with test requirements.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 3

Part 5 Chapter 4 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................... 6 1 Introduction.........................................................................................6 1.1 Introduction..................................................................................... 6 1.2 Scope..............................................................................................6 1.3 Application....................................................................................... 6 2 Class notations.................................................................................... 6 2.1 Ship type notations.......................................................................... 6 2.2 Additional notations.......................................................................... 7 3 Documentation.....................................................................................7 3.1 Documentation requirements............................................................. 7 4 Product certificates..............................................................................8 4.1 Certification requirements.................................................................. 8 5 Testing................................................................................................. 8 5.1 Survey and testing during newbuilding................................................8 Section 2 Hull........................................................................................................ 10 1 General.............................................................................................. 10 1.1 Arrangement.................................................................................. 10 1.2 Calculation scope............................................................................ 10 2 Hull girder loads for direct strength analysis.....................................11 2.1 Longitudinal strength analysis.......................................................... 11 2.2 Transverse strength analysis............................................................ 11 3 Pillars.................................................................................................11 3.1 Below deck connection under compressive loads................................. 11 3.2 Below deck connection under tension loads........................................ 12 4 Finite element analysis...................................................................... 13 4.1 Global model.................................................................................. 13 4.2 Hull girder yield criteria................................................................... 13 4.3 Local strength analysis.................................................................... 13 5 Fatigue strength................................................................................ 13 5.1 General..........................................................................................13 5.2 Structural details to be assessed using prescriptive analysis................. 14 5.3 Structural details to be assessed using finite element analysis with rule loads............................................................................................ 14 6 Glass structure.................................................................................. 14

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 4

Part 5 Chapter 4 Contents

CONTENTS

6.2 Balcony doors.................................................................................14 6.3 Balcony railing................................................................................14 6.4 Fixed- and movable glass roofs........................................................ 15 Section 3 Systems and equipment........................................................................ 17 1 Emergency source of electrical power and emergency installations.......................................................................................... 17 1.1 Electrical systems........................................................................... 17 1.2 Lighting......................................................................................... 18 Section 4 Stability................................................................................................. 19 1 Stability............................................................................................. 19 1.1 Application..................................................................................... 19 1.2 Intact stability................................................................................ 19 Changes – historic................................................................................................ 20

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 5

Part 5 Chapter 4 Contents

6.1 Glass superstructure side.................................................................14

1 Introduction 1.1 Introduction These rules apply to vessels intended for transportation of more than 12 passengers, with class notations Passenger ship or Ferry.

1.2 Scope The rules in this chapter give requirements specific to passenger vessels.

1.3 Application 1.3.1 The requirements in this chapter are supplementary to the rules in Pt.2, Pt.3 and Pt.4 applicable for the assignment of the main class. General reference is made to DNVGL-CG-0138 Direct strength analysis of hull structures in passenger ships, for general ship type information, design concepts and a description of an acceptable rule assessment procedure. 1.3.2 For passenger vessels with class notation Ferry, Ch.3 shall be applied for the RO/RO spaces.

2 Class notations 2.1 Ship type notations 2.1.1 Vessels built in compliance with the requirements as specified in Table 1 will be assigned the class notations as follows: Table 1 Ship type notations

Class notation

Description

Qualifier

Design requirements, rule references

Passenger ship

Ship arranged for transport of more than 12 persons.

<none>

Sec.1 to Sec.4

Ship arranged for transport of more than 12 persons and arranged for carriage of vehicles on enclosed decks.

A

Sec.1 to Sec.4, Ch.3 for RO/RO spaces

Ship arranged for transport of more than 12 persons and arranged for carriage of vehicles on weather deck only.

B

Sec.1 to Sec.4, Ch.3 for RO/RO spaces

Ferry

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 6

Part 5 Chapter 4 Section 1

SECTION 1 GENERAL

2.2.1 The following additional notations, as specified in Table 2, are typically applied to passenger ships with ship type notations according to Table 1: Table 2 Additional notations Class notation

Description

Application

COMF(C-crn)

Comfort class covering requirements for improved indoor climate. crn denotes comfort rating number.

Passenger ships

COMF(V-crn)

Comfort class covering requirements for noise and vibration. crn denotes comfort rating number.

Passenger ships

VIBR

Ship meets specified vibrations level criteria measured at pre-defined positions for machinery, components, equipment and structure.

Passenger ships

3 Documentation 3.1 Documentation requirements 3.1.1 General General requirements for documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2 and Pt.1 Ch.3 Sec.3. Table 3 Documentation requirements Object

Ship hull structure

Superstructure

Propulsion and steering

Documentation type

Additional description

H081 - Global strength analysis

When required by Sec.2 [1.2].

H085 - Fatigue analysis

When required by Sec.2 [1.2].

FI

H050 - Structural drawing

Connections between door frames and bulkheads.

AP

H080 - Strength analysis

Glass roofs

FI

Z261 - Test report

Prefabricated balconies, see [5.1.2].

FI

Z261 - Test report

Balcony doors, see [5.1.3].

FI

Z261 - Test report

Balcony railing, see [5.1.4]..

FI

Z261 - Test report

Glass walls, see [5.1.5]

FI

Z070 - Failure mode description

Shall be submitted prior to detail design plans. See also IACS UR M69.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Info FI

AP

Page 7

Part 5 Chapter 4 Section 1

2.2 Additional notations

4.1 Certification requirements 4.1.1 General Products shall be certified as required by Table 4. Table 4 Certification requirements Certificate type

Issued by

Certification standard

Cargo securing devices, fixed

PC

DNV GL

DNVGL-CP-0068

Cargo securing devices, portable

PC

Object

Additional description

If certified by the Society, DNVGL-CP-0068, shall be applied.

For general certification requirements, see Pt.1 Ch.3 Sec.4. For a definition of the certification types, see Pt.1 Ch.3 Sec.5.

5 Testing 5.1 Survey and testing during newbuilding 5.1.1 General Survey and testing requirements are given in Pt.2. 5.1.2 Prefabricated balcony module 2 Prefabricated balcony modules shall be structurally tested with a test load of 0.25 t/m . No visual damage or permanent deflections upon removal of the test load shall occur. A test report (TR), as defined in Pt.1 Ch.1 Sec.4 [2.1.1], signed by the manufacturer, shall be submitted to the Society. 5.1.3 Balcony doors Strength test of balcony doors shall be carried out in accordance with the following procedure: 1) 2) 3) 4) 5)

The balcony door together with its frame shall be supported the same way as on board the ship. The testing pressure is equal to the design rule pressure and shall be applied uniformly over the entire area of the door as far as this is practicable. The load shall remain for at least 5 minutes. The test will be successful if no visible damage or permanent deformation to the door and its frame occurs. A test report shall be provided to the society.

5.1.4 Balcony railing An impact test according to EN 12600, or equivalent, shall be carried out to demonstrate that the glass pane will not fall out under accidental loading. 5.1.5 Glass superstructure side 1)

For glass side walls which extend between decks, an impact test shall be carried out as per EN 12600 pendulum test, to demonstrate that the glass pane will not fall out in case of an accidental load. A TR

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 8

Part 5 Chapter 4 Section 1

4 Product certificates

Figure 1 Load cycles for testing of side wall glass pane

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 9

Part 5 Chapter 4 Section 1

2)

shall be submitted to the Society. If the glass wall consists of several elements, the elements within one meter from the lowest deck need to be tested. For glass elements that are not supported along all four edges, a strength test shall be carried out. The glass pane for testing shall be supported with an similar arrangement as the actual arrangement on board the vessel. The test pressure shall be the actual design pressure Pd. The test pressure shall be achieved gradually within 30 seconds and reduced to zero within 30 seconds. A minimum of 3 load cycles shall be done. After the load cycles, it shall be kept constant for 5 minutes (see Figure 1). The test will be considered successful if no visible damage occurs to the glass or its supporting arrangements. A test report (TR) shall be submitted to the Society.

1 General 1.1 Arrangement Passenger ships often have multiple decks and long superstructures with many openings. The side and end bulkheads of the superstructure shall be effectively supported. Adequate transition arrangements shall be fitted at the ends of effective continuous longitudinal strength members in the deck and bottom structures.

1.2 Calculation scope 1.2.1 Longitudinal strength For passenger ships, the superstructure is normally contributing to the longitudinal strength. In order to determine the effectiveness of the superstructure and the normal- and shear stress distribution, direct strength calculations using global finite element analysis will normally be required.This will depend on the arrangement and continuity of the primary longitudinal shear members, i.e. ship side and longitudinal bulkheads. The global direct strength model, when required, shall also be used for the strength assessment of the pillars in order to account for both the loads arising from the global hull girder deflection and the local design deck loads. 1.2.2 Local finite element analysis for peak stress and fatigue assessment To obtain a stress distribution in structural elements with discontinuities or geometrical irregularities, e.g. recesses for doors and windows, knuckles, etc., and to evaluate local peak stress and fatigue stress range, local models with fine mesh are required. Local structural strength analysis as given in Pt.3 Ch.7 Sec.4 applies to evaluate local peak stresses. The fatigue scope is defined in [5]. The required fine mesh analysis and the selection of critical locations will depend on the arrangement of the ship and the level of the global stresses. 1.2.3 Transverse strength Required scope for transverse strength analysis will be considered case by case based on the number of transverse bulkheads and other transverse strength members. When required, relevant dynamic load cases are described in [2.2]. 1.2.4 Bow impact For unconventional ship designs with extreme flare angle and where decks in the fore ship have large openings and steps, and with limited continuous longitudinal structure, a direct bow impact analysis may be required, to verify the overall strength of the bow structure. For bow impact direct analysis, see Pt.3 Ch.10 Sec.1 [3.3.5], for design loads and acceptance criteria. 1.2.5 Docking For large passenger ships that may have large docking weight, special strength calculation of the bottom structure in way of the docking blocks may be required. See Pt.3 Ch.3 Sec.5 [3.4] regarding requirements for docking. Acceptance criteria for direct docking analysis based on beam- or finite element (FE) analysis, to be taken according to: — beam analysis: Pt.3 Ch.6 Sec.6 [2.2], AC-I — FE analysis: Pt.3 Ch.7 Sec.3 Table 1, AC-I.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 10

Part 5 Chapter 4 Section 2

SECTION 2 HULL

If one stiffener is subject to more than one load area, a direct strength analysis shall be used to determine the required section modulus.

2 Hull girder loads for direct strength analysis 2.1 Longitudinal strength analysis For passenger vessels the hull girder stresses in finite element analysis may normally be determined by consideration of the most severe combinations of static and dynamic vertical hull girder bending moments and shear forces, corresponding to design load scenario 2 in Pt.3 Ch.4 Sec.7 Table 1. For special design where the torsional response is considered critical, oblique sea conditions will be required. 2.1.1 Load application Acceptable methods for load application are described in DNVGL-CG-0138 Direct strength analysis of hull structures in passenger ships. The applied loads on the FE model should be controlled against the achieved still water- and wave bending moment and shear force curves to ensure agreement with the rule required bending moment and shear force distributions.

2.2 Transverse strength analysis 2.2.1 Static loads for transverse strength analysis Deck loads shall be applied as pressure loads to all decks above the bulkhead deck or life boat embarkation deck such that the sum of the ships steel weight and deck loads equal the displacement at the considered loading condition. 2.2.2 Direct dynamic loads The design wave load cases which shall be used to evaluate the transverse strength of the ship structure are the beam sea load cases, heeling both sides, which maximizes the transverse acceleration at upper deck level. The load case shall be established using a recognized wave load software. Alternatively, rule envelope acceleration, ay-env, according to Pt.3 Ch.4 Sec.3 [3.3.2] at upper deck level, may be applied as target value to establish the dynamic load case for racking analysis. 2.2.3 Rule dynamic loads For ship designs with evenly distributed transverse bulkheads below bulkhead deck and the lower structure can be considered stiff with respect to transverse displacement, the rule transverse envelope acceleration can be applied directly on all decks above bulkhead deck.

3 Pillars 3.1 Below deck connection under compressive loads Smooth transmission of forces between pillars above and below deck shall be provided. The stress in the contact area shall not exceed the yield stress of the material under the pillar loads.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 11

Part 5 Chapter 4 Section 2

1.2.6 Wheel loading Decks exposed to trolleys used in the handling of luggage shall satisfy the requirements given in Pt.3 Ch.10 Sec.5. The trolleys shall be regarded as cargo handling vehicles in harbour condition.

For pillars under tension loads, the average stress based on the contact area shall not exceed the values given in Pt.3 Ch.6 Sec.6 [3.2]. Full penetration welding shall be used for connections of local elements.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 12

Part 5 Chapter 4 Section 2

3.2 Below deck connection under tension loads

4.1 Global model 4.1.1 General For model extent, mesh arrangement, model idealisation and boundary conditions, see DNVGL-CG-0138 Sec.3. 4.1.2 Boundary conditons for transverse strength assessment If the transverse strength analysis is based on dynamic loadcase established using a wave load software as described in [2.2.2], standard boundary conditions as specified in Pt.3 Ch.7 Sec.2 [2] should be applied. If the transverse strength analysis is based on the dynamic loads as described in [2.2.3], the global model may be fixed in all freedoms of translation at bulkhead deck.

4.2 Hull girder yield criteria Stresses in plating of all effective hull girder structural members shall not exceed the permissible values as given in Table 1. Table 1 Permissible stresses for global finite element analysis Permissible axial and principal stress

Permissible shear stress

Permissible von Mises stress

175/k

110/k

220/k

4.3 Local strength analysis 4.3.1 Control of peak stresses In order to control the plastic deformation in corners of deck, bulkhead and wall openings, the peak stresses shall be calculated with the use of fine mesh local models. Peak stresses shall be calculated based on the loads described in [2]. See Pt.3 Ch.7 Sec.4 [4.2] for acceptable stress criteria for peak stresses. 4.3.2 Shear stress control To calculate shear stresses in areas with door and window openings or cut-outs, e.g. due to ventilation, piping cable ducts, in longitudinal bulkheads and side and vertical walls, local models with fine mesh shall be made. See Pt.3 Ch.7 Sec.4 [4.2] for acceptable stress criteria for peak stresses.

5 Fatigue strength 5.1 General For detailed description of the fatigue requirements to main class and fatigue assessment procedure, see Pt.3 Ch.9 and DNVGL-CG-0129 Fatigue assessment of ship structures, respectively. This sub-section describes the scope. A prescriptive fatigue assessment procedure for passenger vessel is defined in DNVGL-CG-0138 Direct strength analysis of hull structures in passenger ships.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 13

Part 5 Chapter 4 Section 2

4 Finite element analysis

End connections of longitudinal stiffeners in the outer shell below the freeboard deck shall be assessed according to Pt.3 Ch.9, for ships with L > 150 m. Relative deflections and double hull bending can be ignored.

5.3 Structural details to be assessed using finite element analysis with rule loads For vessels, for which direct hull girder strength calculation is required according to [1.2.1], the following areas shall be assessed according to DNVGL-CG-0129 Fatigue assessment of ship structures, based on local FE models for free plate edges and hot spot models for welded details: for free plate edges and hot spot models for welded details: — — — —

corner details of door and window openings in longitudinal bulkheads and side walls corners of large deck openings corners of openings in side shell critical details for racking response, described in Ch.3 Sec.2 [8.3], for combined passenger and RO/RO vessels, i.e. Ferry class notation, with multiple decks and limited extent of transverse bulkheads above bulkhead deck. Loads and methods shall be applied according to Ch.3.

Number of details and possible fatigue assessment requirements to other details will be determined on a case-by-case basis, depending on the nominal stress level from the global FE analysis.

6 Glass structure 6.1 Glass superstructure side Glass walls which extend between decks shall satisfy the following requirements: The thickness of the glass pane shall be calculated according to Pt.3 Ch.12 Sec.6 [4] as for windows. Glass panes shall be made from toughened safety glass. The glass pane shall be supported along all its four sides. Other supporting arrangements may be accepted provided testing according to Sec.1 [5.1.5] 2) is done. Hand-railing shall be provided. Alternatively, laminated glass panes shall be used.

6.2 Balcony doors The design of the door glass pane and its supporting frame shall be capable of withstanding the design pressure according to Pt.3 Ch.4 Sec.5 [3.3]. To verify the adequacy of the design, a strength test shall be carried out according to Sec.1 [5.1.3]. Thickness of the door glass pane shall be calculated according to Pt.3 Ch.12 Sec.6 [4]. The minimum glass thickness for doors located 1.7Cw above scantling draft is 6 mm. Cw is defined in Pt.3 Ch.1 Sec.4 [2.3].

6.3 Balcony railing Protective railing shall be installed on all balconies as per Regulation 25 Annex I LL. Alternatively, railing with glass elements can be used provided they are made of: 1) 2)

monolithic glass with a minimum thickness of 6.0 mm and top rail with a minimum section modulus of 3 17 cm laminated glass with a minimum thickness for each glass pane equal to 4 mm.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 14

Part 5 Chapter 4 Section 2

5.2 Structural details to be assessed using prescriptive analysis

The glass elements shall be supported at minimum two opposite sides by continuous line support.

6.4 Fixed- and movable glass roofs 6.4.1 Design loads The minimum forces acting on the glass roof and the supporting structure shall normally be taken as: Vertical force: 2

The pressure Pdl, in kN/m , due to this distributed load for the static plus dynamic (S+D) design load scenario shall be derived for each dynamic load case and shall be taken as:

where:

Pdl-s = static pressure, in kN/m2, due to the distributed load, shall be defined by the designer. Minimum 2

0.15 t/m + self weight of glass roof

Pdl-d = dynamic pressure, in kN/m2, due to the distributed load, in kN/m2, shall be taken as: fβ aZ

= as defined in Pt.3 Ch.4 Sec.4

PV AH

= Pdl AH

2

= vertical envelope acceleration, in m/s , at the centre of gravity of the distributed load, for the considered load case, shall be obtained according to Pt.3 Ch.4 Sec.3 [3.3] 2

= horizontal projected area of the glass roof in m .

Transverse force on side walls in kN:

PT PSI AT

= PSI AT = side pressure taken from Pt.3 Ch.4 Sec.5 [3.3]

2

= transverse projected area of the glass roof in m .

Loads for horizontal stoppers in kN: Combine PVC with PT

PVC Av

= Pdl g

0

Av

2

= vertical projected area of the glass roof in m .

6.4.2 Operational limitations If the roof is intended to be operated in at wind speeds exceeding 15 m/s, additional direct calculations may be required.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 15

Part 5 Chapter 4 Section 2

The height of the railing shall not be less than 1.0 m. Stanchions shall be fitted, not more than 3.0 m apart, 3 with minimum section modulus of 40 cm . The stanchions shall be rigidly fixed at their lower ends to resist rotational displacements.

6.4.3 Stoppers and locking devices The stoppers and locking devices shall be provided such that in the event of failure of the hydraulic system, the roof will remain in open or closed position, respectively.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 16

Part 5 Chapter 4 Section 2

The restriction shall be stated in the operation manual for the vessel.

1 Emergency source of electrical power and emergency installations 1.1 Electrical systems 1.1.1 General Passenger vessels shall have an electrical installation complying with the requirements in Pt.4 Ch.8 with the clarifications and additions given in this section. 1.1.2 Fire zones Electrical distribution systems shall be so arranged that fire in any main vertical zone, as defined in Pt.4 Ch.11, will not interfere with services essential for safety in any other such zone. This requirement will be met if main and emergency feeders passing through any such zone are separated both vertically and horizontally as widely as is practicable. 1.1.3 Emergency generator Where the emergency source of electrical power is a generator, it shall be started automatically. The emergency power supply system shall have capacity to supply the services listed in Pt.4 Ch.8 Sec.2 Table 1 for a period of 36 hours. 1.1.4 Additional emergency consumers In addition to the services stated in Pt.4 Ch.8 Sec.2 Table 1, the following services shall be supplied by the emergency power supply system: 1)

For a period of 36 hours: — emergency lighting in alleyways, stairways and exits giving access to the muster and embarkation stations, as required by SOLAS regulation III/11.5 — the public address system or other effective means of communication which is provided throughout the accommodation, public and service spaces — the means of communication which is provided between the navigating bridge and the main fire control station — the fire door holding and release system — the automatic sprinkler pump, if any — the emergency bilge pump, and all the equipment essential for the operation of electrically powered remote controlled bilge valves.

2)

For a period of half an hour: — the emergency arrangements to bring the lift cars to deck level for the escape of persons. The passenger lift cars may be brought to deck level sequentially in an emergency.

1.1.5 Transitional source of emergency power In addition to the services stated in Pt.4 Ch.8 Sec.2 Table 1, the following services shall be supplied by transitional source of power for a period of half an hour: 1) 2)

emergency lighting in alleyways, stairways and exits giving access to the muster and embarkation stations, as required by SOLAS regulation III/11.5 the fire door holding and release system.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 17

Part 5 Chapter 4 Section 3

SECTION 3 SYSTEMS AND EQUIPMENT

1.2.1 General Passenger ships shall be provided with lighting systems as required by Pt.4 Ch.8. In addition, low-location lighting and supplementary lighting shall be installed as follows: 1.2.2 Low-location lighting Passenger ships shall be provided with low-location lighting (LLL) complying with IMO Res. A.752(18). 1.2.3 Supplementary lighting general In passenger ships, supplementary lighting shall be provided in all cabins to clearly indicate the exit so that occupants will be able to find their way to the door. Such lighting, which may be connected to an emergency source of power or have a self-contained source of electrical power in each cabin, shall automatically illuminate when power to the normal cabin lighting is lost and remain on for a minimum of 30 min. (SOLAS Ch. II-1/41.6). 1.2.4 Supplementary lighting passenger RO/RO vessels For RO-RO passenger ships SOLAS regulation II-1/42-1, in addition to the emergency lighting required by SOLAS regulation II-1/42.2, on every passenger ship with ro-ro cargo spaces or special category spaces as defined in SOLAS regulation II-2/3: 1)

2)

All passenger public spaces and alleyways shall be provided with supplementary electric lighting that can operate for at least three hours when all other sources of electric power have failed and under any condition of heel. The illumination provided shall be such that the approach to the means of escape can be readily seen. The source of power for the supplementary lighting shall consist of accumulator batteries located within the lighting units that are continuously charged, where practicable, from the emergency switchboard. Alternatively, any other means of lighting which is at least as effective may be accepted by the Administration. The supplementary lighting shall be such that any failure of the lamp will be immediately apparent. Any accumulator battery provided shall be replaced at intervals having regard to the specified service life in the ambient conditions that they are subject to in service; and A portable rechargeable battery operated lamp shall be provided in every crew space alleyway, recreational space and every working space which is normally occupied unless supplementary emergency lighting, as required by sub paragraph.1, is provided.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 18

Part 5 Chapter 4 Section 3

1.2 Lighting

1 Stability 1.1 Application Ships with class notation Passenger ship and Ferry shall comply with the requirements according to [1.2].

1.2 Intact stability 1.2.1 Intact stability criteria Passenger ships shall comply with Pt.3 Ch.15 with the supplementing requirements as given in IMO 2008 Intact Stability Code (IMO Res. MSC.267(85)) Part A Ch. 3.1.1 and 3.1.2. 1.2.2 Loading conditions Compliance with the stability requirements shall be documented for the standard loading conditions given in IMO 2008 Intact Stability Code (IMO Res. MSC.267(85)) Part B Ch. 3.4.1.1.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 19

Part 5 Chapter 4 Section 4

SECTION 4 STABILITY

July 2017 edition

Amendments July 2017 • Sec.3 Systems and equipment — Sec.3 [1.1.3]: Paragraph has been deleted. — Sec.3 [1]: All paragraphs except paragraph 1.3.9 have been deleted. — Sec.3 [1]: New paragraph 1.1.5 has been added.

Main changes January 2017, entering into force July 2017 • Sec.1 General — Sec.1 [5.1.4]: Test requirements for glass side walls consiting of more than one element and glass side walls not supported on all four edges have been specified.

• Sec.2 Hull — Sec.2 [6.1]: Acceptance of glass side walls not supported on all four sides has been implemented.

January 2016 edition

Main changes January 2016, entering into force as from date of publication • Sec.2 Hull — [1.2.3] and [2.2]: Scope and load combinations for global FE transverse strength analysis is clarified — [6.3]: More detailed requirements to balcony railings included

October 2015 edition

General This is a new document. The rules enter into force 1 January 2016.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.4. Edition January 2018 Passenger ships

DNV GL AS

Page 20

Part 5 Chapter 4 Changes – historic

CHANGES – HISTORIC

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition January 2018

Part 5 Ship types Chapter 5 Oil tankers

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the July 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.5. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018 Topic

Reference

Description

FSS-code

Sec.11 [3.1.6]

Updated the requirement to include a visual and audible alarm both inside and outside the compartment where an inert gas system is located (from the updated FSS-code).

Vetting

Sec.9 [7.1]

Included a requirement for instrumentation capable of detecting O2-content, also for non-inerted tankers.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 3

Part 5 Chapter 5 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................. 10 1 Introduction.......................................................................................10 1.1 Introduction................................................................................... 10 1.2 Scope............................................................................................ 10 1.3 Application..................................................................................... 10 2 Class notations.................................................................................. 11 2.1 Ship type notations for oil tankers.................................................... 11 2.2 Additional notations........................................................................ 12 2.3 Register information........................................................................ 13 3 Definitions..........................................................................................13 3.1 Terms............................................................................................ 13 4 Documentation...................................................................................16 4.1 Documentation requirements............................................................16 4.2 Certification requirements................................................................ 20 5 Testing............................................................................................... 21 5.1 Testing during newbuilding...............................................................21 Section 2 Hull........................................................................................................ 23 1 General.............................................................................................. 23 1.1 Application..................................................................................... 23 1.2 Common structural rules................................................................. 23 2 Hull strength......................................................................................23 2.1 Vertically corrugated bulkhead without stool.......................................23 2.2 Emergency towing.......................................................................... 24 3 Fatigue assessment........................................................................... 24 3.1 General..........................................................................................24 3.2 Longitudinals in way of end-supports................................................ 25 3.3 Lower hopper knuckle..................................................................... 25 4 Direct strength calculations............................................................... 25 4.1 General..........................................................................................25 4.2 Direct strength calculations for ships with length above 90 m............... 26 4.3 Load conditions.............................................................................. 27 Section 3 Ship arrangement and stability............................................................. 28 1 Intact stability................................................................................... 28

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 4

Part 5 Chapter 5 Contents

CONTENTS

2.1 General..........................................................................................28 2.2 Arrangements of barges.................................................................. 29 3 Tank and pump room arrangement................................................... 29 3.1 Segregated ballast tanks................................................................. 29 3.2 Protection of cargo tanks................................................................. 30 3.3 Cargo tanks and slop tanks............................................................. 31 3.4 Double bottom in pump rooms......................................................... 32 4 Arrangement of access and openings to spaces and tanks.................32 4.1 Accommodation and non-hazardous spaces........................................ 32 4.2 Access to and within hazardous spaces..............................................33 5 Protection of crew............................................................................. 33 5.1 Arrangement.................................................................................. 33 6 Cofferdams, pipe tunnels and deck trunks.........................................33 6.1 Cofferdams.....................................................................................33 6.2 Pipe tunnels and deck trunks........................................................... 34 7 Diesel engines for emergency fire pumps.......................................... 34 7.1 General..........................................................................................34 8 Chain locker and anchor windlass..................................................... 35 8.1 General..........................................................................................35 9 Equipment in tanks and cofferdams.................................................. 35 10 Surface metal temperatures in hazardous areas..............................35 11 Signboards....................................................................................... 35 11.1 References................................................................................... 35 Section 4 Piping systems in cargo area................................................................ 36 1 Piping materials.................................................................................36 1.1 Selection and testing.......................................................................36 1.2 Special requirements for cargo piping system.....................................36 1.3 Plastic pipes in cargo area............................................................... 36 1.4 Aluminium coatings......................................................................... 36 2 Piping systems not used for cargo oil................................................36 2.1 General..........................................................................................36 2.2 Drainage of pump rooms, cofferdams, pipe tunnels, ballast and fuel oil tanks.................................................................................................. 37 2.3 Fore peak ballast tank.....................................................................38 2.4 Oil discharge monitoring and control systems..................................... 39 2.5 Oil record book, shipboard oil pollution emergency plan and ship-toship transfer........................................................................................ 39 2.6 Air, sounding and filling pipes...........................................................39

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 5

Part 5 Chapter 5 Contents

2 Location and separation of spaces.....................................................28

3.1 General..........................................................................................40 3.2 Cargo piping systems...................................................................... 41 3.3 Cargo piping systems for barges...................................................... 42 3.4 Testing...........................................................................................43 4 Cargo heating.................................................................................... 43 4.1 General..........................................................................................43 4.2 Steam heating................................................................................43 4.3 Thermal oil heating......................................................................... 43 4.4 Heating of cargo with temperatures above 120°C............................... 44 5 Bow and stern loading and unloading arrangements......................... 44 5.1 General..........................................................................................44 5.2 Piping arrangement......................................................................... 44 Section 5 Gas-freeing and venting of cargo tanks................................................ 46 1 Gas-freeing of cargo tanks................................................................ 46 1.1 General..........................................................................................46 1.2 Gas-freeing of cargo tanks for barges............................................... 47 2 Cargo tank venting systems.............................................................. 47 2.1 General..........................................................................................47 2.2 System design................................................................................48 2.3 Venting of cargo tanks for barges..................................................... 49 2.4 Volatile organic compounds (VOC).................................................... 49 Section 6 Ventilation systems within the cargo area outside the cargo tanks....... 50 1 Ventilation systems........................................................................... 50 1.1 General..........................................................................................50 1.2 Fans serving hazardous spaces.........................................................51 2 Ventilation arrangement and capacity requirements......................... 52 2.1 General..........................................................................................52 2.2 Non-hazardous spaces..................................................................... 52 2.3 Cargo handling spaces.....................................................................52 2.4 Other hazardous spaces normally entered..........................................53 2.5 Spaces not normally entered............................................................53 2.6 Ventilation systems for barges..........................................................53 Section 7 Fire protection and extinction............................................................... 54 1 Fire safety measures for tankers....................................................... 54 1.1 Application..................................................................................... 54

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 6

Part 5 Chapter 5 Contents

3 Cargo oil systems.............................................................................. 40

1 General.............................................................................................. 55 1.1 Application..................................................................................... 55 1.2 Insulation monitoring...................................................................... 55 2 Electrical installations in hazardous areas......................................... 55 2.1 General..........................................................................................55 3 Area classification..............................................................................56 3.1 General..........................................................................................56 3.2 Tankers for carriage of products with flashpoint not exceeding 60°C.......56 3.3 Tankers for carriage of products with flashpoint exceeding 60°C............ 58 4 Inspection and testing.......................................................................58 4.1 General..........................................................................................58 5 Maintenance.......................................................................................59 5.1 General..........................................................................................59 6 Signboards......................................................................................... 59 6.1 General..........................................................................................59 Section 9 Instrumentation and automation.......................................................... 60 1 General requirements........................................................................ 60 2 Cargo valves and pumps- control and monitoring..............................60 2.1 General..........................................................................................60 2.2 Computer based systems for cargo handling...................................... 60 2.3 Centralised cargo control................................................................. 60 2.4 Design of integrated cargo and ballast systems.................................. 61 3 Cargo tank level monitoring.............................................................. 61 3.1 General..........................................................................................61 4 Cargo tank overflow protection......................................................... 62 5 Oil and water interface detector........................................................62 6 Gas detection in cargo pump room....................................................62 7 Gas detection outside cargo pumprooms........................................... 62 7.1 Portable gas detection..................................................................... 62 7.2 Fixed gas detection......................................................................... 63 8 Installation requirements for analysing units.................................... 64 Section 10 Ships for alternate carriage of oil cargo and dry cargo........................ 65 1 General.............................................................................................. 65 1.1 Class notation................................................................................ 65 1.2 Basic assumptions...........................................................................65 2 Cargo area arrangement and systems............................................... 65

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 7

Part 5 Chapter 5 Contents

Section 8 Area classification and electrical installations....................................... 55

2.2 Arrangement and access to compartments......................................... 66 2.3 Bilge, drainage and cargo piping.......................................................66 2.4 Cleaning and gas-freeing................................................................. 67 2.5 Ventilation......................................................................................67 3 Gas measuring equipment................................................................. 68 3.1 Measurement of hydrocarbon gases.................................................. 68 4 Instructions....................................................................................... 68 4.1 Operations manual.......................................................................... 68 4.2 Instructions onboard....................................................................... 68 Section 11 Inert gas systems............................................................................... 69 1 General.............................................................................................. 69 1.1 Application..................................................................................... 69 1.2 Operation and equipment manual..................................................... 69 2 Materials............................................................................................ 69 2.1 General..........................................................................................69 3 Arrangement and general design.......................................................70 3.1 General..........................................................................................70 3.2 Piping arrangement......................................................................... 70 3.3 Inerting of double hull spaces.......................................................... 72 3.4 Fresh air intakes.............................................................................72 3.5 Level measuring of inerted tanks...................................................... 72 3.6 Prevention of gas leakage into non-hazardous spaces.......................... 72 4 Inert gas production and treatment.................................................. 73 4.1 General..........................................................................................73 4.2 Flue gas system............................................................................. 73 4.3 Inert gas generator.........................................................................74 4.4 Gas cleaning and cooling................................................................. 74 4.5 Water supply.................................................................................. 74 4.6 Water discharge..............................................................................74 5 Instrumentation.................................................................................74 5.1 General..........................................................................................74 5.2 Indication.......................................................................................75 5.3 Monitoring......................................................................................75 6 Survey and testing............................................................................ 78 6.1 Survey...........................................................................................78 6.2 Testing...........................................................................................79

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 8

Part 5 Chapter 5 Contents

2.1 Design of cargo oil tanks................................................................. 65

1 General.............................................................................................. 80 1.1 Application..................................................................................... 80 1.2 Documentation............................................................................... 80 2 Arrangement and systems................................................................. 80 2.1 Arrangement.................................................................................. 80 2.2 Tank venting.................................................................................. 80 2.3 Pumping and piping system............................................................. 80 2.4 Gas detection................................................................................. 80 2.5 Protection inside slop tanks..............................................................80 3 Signboards and instructions.............................................................. 81 3.1 General..........................................................................................81 Section 13 Cargo tank cleaning arrangements......................................................82 1 General.............................................................................................. 82 1.1 Application..................................................................................... 82 1.2 Tank water washing systems............................................................ 82 Appendix A List of cargoes................................................................................... 83 1 List of oil cargoes.............................................................................. 83 1.1 General..........................................................................................83 2 Cargoes other than oils..................................................................... 84 Changes – historic................................................................................................ 85

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 9

Part 5 Chapter 5 Contents

Section 12 Protected slop tank............................................................................. 80

1 Introduction 1.1 Introduction These rules apply to ships intended for carriage of oil in bulk.

1.2 Scope 1.2.1 The rules in this chapter give requirements related to: — — — —

safety hazards marine pollution hazards additional hull attributes functional capability of systems.

Incorporated in the rules are some SOLAS Ch. II-2 requirements, where these are specifically mentioned as applicable for tankers only. Requirements of MARPOL Annex I, insofar as design and equipment are concerned, are also covered. 1.2.2 Machinery installations and their auxiliary systems that support cargo handling, shall meet the same rule requirements as if they were considered to support a main function, see Pt.1 Ch.1 Sec.1 [1.2].

1.3 Application 1.3.1 These rules apply to ships intended for the carriage of liquid oil cargoes in bulk with a flashpoint not exceeding 60°C (closed cup test), as well as ships heating its cargo to within 15°C of its flashpoint. For ships intended for carriage of oil products with flashpoint exceeding 60°C, the requirements in Sec.2, Sec.3 [1], Sec.3 [2.1.8] to Sec.3 [2.1.9], Sec.3 [3], Sec.3 [4.2], Sec.3 [5] to Sec.3 [6], Sec.3 [9], Sec.4 [1] to Sec.4 [4], Sec.7, Sec.8 [3.3.1] and Sec.9 [1] to Sec.9 [5] apply. Liquid cargoes with vapour pressure above atmospheric pressure at 37.8°C reid vapor pressure (RVP) shall not be carried unless the ship is especially designed and equipped for this purpose. Relevant requirements may be found in Ch.6, e.g. Ch.6 Sec.1 [3], Ch.6 Sec.7 and Ch.6 Sec.15 [2.2]. 1.3.2 The requirements in this chapter are supplementary to those given for the assignment of main class. 1.3.3 Oil cargoes and cargoes other than oils, covered by the classification in accordance with this chapter, are listed in App.A. 1.3.4 Oil tankers of 20 000 dwt and above and all ships fitted with equipment for crude oil washing, shall fulfil the requirements for inert gas plants as given in Sec.11. 1.3.5 Simultaneous carriage of dry cargo (including vehicles and passengers) and oil cargo with flashpoint not exceeding 60°C is not permitted for ships with class notations as stated in Table 1, see SOLAS Ch.II-2 Reg.2.6.5. 1.3.6 Ships designed for alternate carriage of liquid cargoes with a flashpoint not exceeding 60°C and dry cargo shall comply with the requirements in Sec.10 and the requirements to protected slop tank in Sec.12. 3

1.3.7 Tanks for liquids with density exceeding 1.025 t/m , see Pt.6 Ch.1 Sec.3.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 10

Part 5 Chapter 5 Section 1

SECTION 1 GENERAL

2 Class notations 2.1 Ship type notations for oil tankers Vessels built in compliance with the requirements of this chapter will be assigned one of the mandatory class notations and applicable qualifiers as specified in Table 1: Table 1 Ship type notations

Class notation

Description

Tanker for oil

vessel purpose carriage of crude oil and/or oil products in bulk

Tanker for oil products

vessel purpose carriage of oil products in bulk

Tanker for oil products with flashpoint above 60°C

vessel purpose carriage of oil products with flashpoint above 60°C in bulk

Tanker for asphalt/bitumen

vessel purpose carriage of asphalt/bitumen in bulk

Barge for oil

vessel purpose carriage of crude oil and/or oil products in bulk

Barge for oil products

vessel purpose carriage of oil products in bulk

Barge for oil products with flashpoint above 60°C

vessel purpose carriage of oil products with flashpoint above 60°C in bulk

Barge for asphalt/bitumen

vessel purpose carriage of asphalt/bitumen in bulk

Bulk carrier or tanker for oil

vessel purpose carriage of dry bulk cargo alternating with carriage of crude oil and/or oil products in bulk

Bulk carrier or tanker for oil products

vessel purpose carriage of dry bulk cargo alternating with carriage of oil products in bulk

Design requirements, rule reference

This chapter except Sec.3 [2.2], Sec.4 [3.3], Sec.5 [1.2], Sec.5 [2.3] and Sec.10

Ch.11 and this chapter, except Sec.10

This chapter except Sec.3 [2.2], Sec.4 [3.3], Sec.5 [1.2] and Sec.5 [2.3]

2.1.1 The term oil tanker is used as a general reference for ships with class notation Tanker for oil. The term combination carrier is used as a general reference for ships with class notation Bulk carrier or Tanker for oil.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 11

Part 5 Chapter 5 Section 1

1.3.8 Ships carrying asphalt/bitumen or other cargoes which through their physical properties inhibit effective product/water separation and monitoring, may be exempted from the requirements to slop tanks (see Sec.3 [3.4]), oil discharge monitoring system (see Sec.4 [2.4]) and oil/water interface detector (see Sec.9 [5]) in accordance with Regulation 2.4 of MARPOL Annex I.

The additional class notations specified in Table 2, are typically also applied to tankers and combination carriers: Table 2 Additional notations Class notation

Description

Application

Rule reference

CSR

ships designed and built according to IACS common structural rules

mandatory for Tanker for oil and Tanker for oil products with L ≥ 150 m

IACS common structural rules

HL

tanks or holds strengthened for heavy liquid

all ships

Pt.6 Ch.1 Sec.3

Plus

extended fatigue analysis of ship details

all ships

Pt.6 Ch.1 Sec.6

CSA

direct analysis of ship structures

all ships

Pt.6 Ch.2 Sec.7

Bow loading

bow loading arrangement

mandatory for Tanker for oil when installed

CCO

centralised cargo control for liquid cargoes

all ships

Pt.6 Ch.4 Sec.2

ETC

effective tank cleaning

all ships

Pt.6 Ch.4 Sec.4

STL

submerged turret loading system

mandatory when installed

Pt.6 Ch.4 Sec.1

Inert

inert gas system

mandatory if installed on Tanker for oil DWT < 8 000 tonn

Pt.6 Ch.5 Sec.8

SPM

single point mooring

mandatory for Tanker for oil when installed

Pt.6 Ch.5 Sec.12

VCS

system for control of vapour emissions from cargo tanks

mandatory for Tanker for oil and Tanker for oil products

Pt.6 Ch.4 Sec.12

Ch.4 Sec.1

mandatory for ships with class notations: — Bulk carrier ESP

ships subject to an enhanced survey programme

— Bulk carrier or Tanker for oil — Ore carrier Ore carrier or Tanker for oil

Pt.6 Ch.9 Sec.2

— Tanker for chemicals Tanker for C — Tanker for oil — Tanker for oil products.

Hot

cargo tanks designed for high temperature cargo with a specified maximum design cargo temperature

mandatory for ships with notation Tanker for asphalt/bitumen and other oil tankers intended for the carriage of liquid cargo at a temperature higher than 80°C at atmospheric pressure.

CMON

Construction monitoring of hull critical locations

all ships

Pt.6 Ch.1 Sec.12

Pt.6 Ch.9 Sec.7

For a full definition of all additional class notations, see Pt.1 Ch.2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 12

Part 5 Chapter 5 Section 1

2.2 Additional notations

The register information ssp indicates that cargo piping and all equipment in contact with cargo and cargo vapours are made of stainless steel.

3 Definitions 3.1 Terms Table 3 Definitions Terms

Definition

accommodation spaces

spaces used for public spaces, corridors, lavatories, cabins, offices, barber shops, hospital, cinemas, games and hobbies rooms, pantries containing no cooking appliances and similar spaces

air lock

enclosed space for entrance between a hazardous area on open deck and a nonhazardous space, arranged to prevent ingress of gas to the non-hazardous space

cargo area

part of the ship which contains the cargo tanks, pump rooms, cofferdams and similar compartments adjacent to cargo tanks, and includes deck areas over the full beam and length of above spaces The cargo area extends to the full beam and depth of the ship from the aftmost bulkhead of compartment adjacent to the aftmost cargo tanks to the full beam of the forwardmost bulkhead of a compartment adjacent to the forward most cargo tank. Where independent tanks are installed in hold spaces, cofferdams, ballast or void spaces at the after end of the aftermost hold space or at the forward end of the forward-most hold space are excluded from the cargo area.

cargo control room

space used in the control of cargo handling operations

cargo handling spaces

enclosed spaces which contain fixed cargo handling equipment, and similar spaces in which work is performed on the cargo, e.g.: pump rooms

cargo handling systems

piping systems in which cargo liquid, vapour or residue is transferred or likely to occur in operation and includes systems such as cargo pumping systems, cargo stripping systems, drainage systems within the cargo area, cargo tank venting systems, cargo tank washing systems, inert gas systems, vapour emission control systems and gas freeing systems for cargo tanks

cargo tank

liquid tight shell designed to be the primary container of the cargo Cargo tanks shall be taken to include also slop tanks, residual tanks and other tanks containing cargo with a flashpoint not exceeding 60°C.

cargo tank block

part of the ship extending from the aft bulkhead of the aftmost cargo tank to the forward bulkhead of the forward most cargo tank, extending to the full beam and depth of the ship, but not including the area above the deck of the cargo tank

cofferdam

isolating space between two adjacent steel bulkheads or decks. This space may be a dry space or a tank, see Sec.3 [6.1]

control stations

spaces in which the ship’s radio or main navigating equipment or the emergency source of power is located. Spaces where the fire recording or fire control equipment is centralised are also considered to be a fire control station

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 13

Part 5 Chapter 5 Section 1

2.3 Register information

Definition

design vapour pressure p0

maximum gauge pressure at the top of the tank that has been used in the design of the tank

flame arrester

device through which an external flame front cannot propagate and ignite an internal gas mixture

flame screen

flame arrester consisting of a fine-meshed wire gauze of corrosion-resistant material

hazardous area

area in which an explosive gas atmosphere is or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of electrical apparatus Hazardous areas are divided into zone 0, 1 and 2 as defined below and according to the area classification specified in Sec.8 [3]. — Zone 0 Area in which an explosive gas atmosphere is present continuously or is present for long periods. — Zone 1 Area in which an explosive gas atmosphere is likely to occur in normal operation. — Zone 2 Area in which an explosive gas atmosphere is not likely to occur in normal operation and, if it does occur, is likely to do so only infrequently and will exist for a short period only.

high velocity vent valve

cargo tank vent valve which at all flow rates expels the cargo vapour upwards at a velocity of at least 30 m/s, measured at a distance equal to the nominal diameter of the standpipe above the valve outlet opening

non-hazardous area

area not considered to be hazardous

oil discharge monitoring equipment (ODME)

equipment used for controlling the discharge of oily ballast and tank washing water from oil tankers

pressure-vacuum (P/V) valve

valve which keeps the tank overpressure or under-pressure within approved limits

public spaces

portions of the accommodation which are used for halls, dining rooms, lounges and similar permanently enclosed spaces

residual tank

tank particularly designated for carriage of cargo residues and cargo mixtures typically transferred from slop tanks, cargo tanks and cargo piping Residual tanks which are intended for the storage of cargo or cargo residue with a flashpoint not exceeding 60°C or that are connected to cargo handling piping systems serving cargo or slop tanks, shall comply with the requirements for cargo tanks. Residual tanks that are not intended for carriage of cargo, are not required to comply with the requirements of crude oil washing in Sec.13.

segregated ballast tanks

tanks that are completely separated from the cargo oil and fuel oil systems and are permanently allocated to the carriage of ballast or cargoes other than oil or noxious substances as defined in MARPOL

service spaces

spaces used for galleys, pantries containing cooking appliances, lockers, mail and specie rooms, store rooms, workshops other than those forming part of the machinery spaces and similar spaces and trunks to such spaces

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 14

Part 5 Chapter 5 Section 1

Terms

slop tanks

Definition tanks particularly designated for the collection of tank draining, tank washing and other oily mixtures Slop tanks that are intended for the carriage of cargo or cargo residue with a flashpoint not exceeding 60°C or that are connected to cargo handling piping systems serving cargo or slop tanks, shall comply with the requirements for cargo tanks. Slop tanks that are not intended for carriage of cargo, are not required to comply with the requirements of crude oil washing in Sec.13.

spaces not normally entered

cofferdams, double bottoms, duct keels, pipe tunnels, stool tanks, spaces containing cargo tanks and other spaces where cargo may accumulate

spark arrester

a device preventing sparks from the combustion in prime movers, boilers etc. to reach open air

STS

ship-to-ship transfer of oil cargo between oil tankers at sea according to MARPOL Annex I

tank deck

the following decks are designated tank deck: — a deck or part of a deck that forms the top of a cargo tank — part of a deck upon which cargo tanks, cargo hatches, valves, pumps or other equipment intended for loading, discharging or transfer of the cargo, are located — part of a deck within the cargo area, located lower than the top of a cargo tank — deck or part of deck within the cargo area, located lower than 2.4 m above a deck as described above.

tank types

see Ch.6 Sec.1 [2.6]

void space

enclosed space in the cargo area, external to a cargo containment system, not being a hold space, ballast space, fuel oil tank, cargo pump or compressor room, or any space in normal use by personnel

Table 4 Abbreviations Abbreviation

Definition

CCR

cargo control room

LEL

lower explosion limit

MBL

minimum breaking load

NLS

noxious liquid substances

P/V

pressure-vacuum

RVP

Reid vapor pressure

STL

submerged turret loading

STS

ship-to-ship

USCG

United States Coast Guard

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 15

Part 5 Chapter 5 Section 1

Terms

4.1 Documentation requirements 4.1.1 Oil tankers Documentation shall be submitted as required by Table 5. Table 5 Documentation requirements Object

internal access

Documentation type

H200 – Ship structure access manual

Additional description

Info

The plan shall include details enabling verification of compliance with requirements to safe access to cargo tanks, ballast tanks, cofferdams and other spaces within and forward the cargo area as required by SOLAS Ch.II-1 Reg.3-6.

AP

Including: — cargo hatches, butterworth hatches and any other openings to cargo tanks — doors, hatches and any other openings to pump rooms and other hazardous areas vessel arrangement

Z010 – General arrangement plan

— ventilating pipes and openings for cargo hatches, pump rooms and other hazardous areas — doors, air locks, hatches, ventilating pipes and openings, hinged scuttles which can be opened, and other openings to non-hazardous spaces adjacent to the cargo area including spaces in and below the forecastle

FI

— cargo pipes over the deck with shore connections including stern pipes for cargo discharge or pipes for bow loading arrangement. hazardous areas

electrical equipment in hazardous areas

hydrocarbon gas detection and alarm system, fixed

G080 – Hazardous area classification drawing

AP

E170 – Electrical schematic drawing

Single line diagrams for all intrinsically safe circuits, for each circuit including data for verification of the compatibility between the barrier and the field components.

AP

Z030 – Arrangement plan

Where relevant, based on an approved hazardous area classification drawing where location of electric equipment in hazardous area is added (except battery room, paint stores and gas bottle store).

AP

Z163 – Maintenance manual

As specified in Sec.8.

AP

Z030 – Arrangement plan

Shall include fixed gas detection for pumprooms and spaces adjacent to cargo tanks. Shall include arrangement of sampling piping, location of all sampling points, detectors, call points and alarm devices.

FI

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 16

Part 5 Chapter 5 Section 1

4 Documentation

ventilation systems for hazardous cargo areas

oil pollution prevention

cargo handling arrangements

cargo piping system

cargo pumps and remotely operated valves control and monitoring system vapour return systems

oil discharge (ODM) control and monitoring system

Documentation type

Additional description

Info

I200 – Control and monitoring system documentation

AP

S012 – Ducting diagram (DD)

AP

S030 – Capacity analysis

AP

C030 – Detailed drawing

Rotating parts and casing of fans.

I200 – Control and monitoring system documentation

AP AP

S150 – Shipboard oil pollution emergency plan (SOPEP)

Applicable when GT ≥ 150.

AP

Z161 – Operation manual

Ship-to-ship transfer manual (STS). Applicable for oil tankers involved in ship-to-ship transfer when GT ≥ 150.

AP

C030 – Detailed drawing

Gastight bulkhead stuffing boxes: including details of lubrication arrangement and temperature monitoring.

AP

Z161 – Operation manual

VOC management plan, see MARPOL Annex VI Reg.15.

AP

S010 – Piping diagram (PD)

Including cargo stripping system. For vacuum stripping systems details shall include termination of air pipes and openings from drain tanks and other tanks.

AP

For ships with cargo pumprooms specification of temperature monitoring equipment for cargo pumps and shaft penetrations shall be included. S010 – Piping diagram (PD) I200 – Control and monitoring system documentation

AP For ships with cargo pumprooms, specification of temperature monitoring equipment for cargo pumps and shaft penetrations shall be included.

AP

S010 – Piping diagram (PD)

AP

I200 – Control and monitoring system documentation

AP

S010 – Piping diagram (PD)

AP Guidance note: In accordance with IMO MEPC.108(49) as amended

Z161 – Operation manual

by IMO Res. MEPC.240(65) - Revised Guidelines and Specifications for Oil Discharge Monitoring and

AP

Control Systems for Oil Tankers. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

cargo tanks

H210 – Protected tank location drawing

In accordance with MARPOL Annex I Reg. 19 and 22.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

AP

Page 17

Part 5 Chapter 5 Section 1

Object

cargo tanks gasfreeing system

cargo tanks venting system

cargo tanks level measurement system, fixed cargo tanks level alarm system, fixed

Documentation type

Additional description

Info

Z265 – Calculation report

Accidental oil outflow performance in accordance with MARPOL Annex I Reg.23.

FI

S010 – Piping diagram (PD)

Only applicable for fixed mechanical ventilation cargo tank gas freeing system if installed.

AP

S010 – Piping diagram (PD)

Including settings of P/V-devices.

AP

Z100 – Specification

For P/V-devices and other flame arresters: details, flow curves and references to type approval certificates.

FI

I200 – Control and monitoring system documentation Z030 – Arrangement plan

AP Shall indicate type and location of level indicators.

I200 – Control and monitoring system documentation

FI AP

Z030 – Arrangement plan

Shall indicate type and location of sensors, as well as location of audible and visible alarms.

FI

I200 – Control and monitoring system documentation

If required as a secondary means of cargo tank venting as per Sec.5.

AP

Z030 – Arrangement plan

Shall indicate type and location of sensors, as well as location of audible and visible alarms.

FI

cargo temperature monitoring system

I200 – Control and monitoring system documentation

If required by Sec.4 [4.4].

AP

cargo heating system

S010 – Piping diagram (PD)

cargo tanks pressure monitoring system, fixed

bilge system

S010 – Piping diagram (PD)

AP As required by Pt.4 Ch.6 but shall also include bilge and drainage piping systems serving e.g. pump rooms, cofferdams, pipe tunnels and other dry spaces within cargo area. The drawing shall include arrangement for transfer of sludge/bilge water to slop tanks if installed. The drawing shall also include number and location of any bilge level sensors.

AP

As required by Pt.4 Ch.6 but shall also include ballast systems serving ballast tanks in the cargo area.

ballast system

S010 – Piping diagram (PD

The diagram shall include piping arrangement for forepeak tank (if connected to the ballast system serving the cargo area) as well as details related to ballast treatment systems if installed. For ships with cargo pumprooms, specification of temperature monitoring equipment for ballast pumps and shaft penetrations shall be included.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

AP

Page 18

Part 5 Chapter 5 Section 1

Object

Documentation type

Additional description

Info

- non-return valves - deck water seals C030 – Detailed drawing

- double-block and bleed arrangements

AP

- scrubbers - P/V breakers.

S010 – Piping diagram (PD)

Inert gas distribution to cargo tanks, ballast tanks and cargo piping. Shall include connections to e.g. cargo tank venting and vapour return systems.

AP

S010 – Piping diagram (PD)

Piping systems serving the inert gas unit such as exhaust gas, fuel supply, water supply and discharge piping.

AP

Z161 – Operation manual

See MSC/Circ.353 Ch.8 and 11, as amended by MSC/ Circ.387.

AP

inert gas generator

Z100 – Specification

If applicable.

AP

inert gas control and monitoring system

I200 – Control and monitoring system documentation

inert gas system

S010 – Piping diagram (PD)

AP The drawing shall show number of and location of cargo tank washing machines.

S110 – Shadow diagram cargo tanks cleaning systems

crude oil washing machines

AP AP

Z030 – Arrangement plan

- washing machines including installation and supporting arrangements - hand dipping and gas sampling arrangements.

AP

Z161 – Operation manual

In accordance with MEPC.3(XII), as amended by resolution MEPC.81(43).

AP

Z100 – Specification

- manufacturer - type - nozzle diameter

FI

- capacity. AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

4.1.2 Combination carriers Additional documentation for combination carriers shall be submitted as required by Table 6. Table 6 Additional documentation requirements Object cargo handling arrangements

Documentation type Z161 – Operational manual

Additional description See Sec.10 [4.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Info AP

Page 19

Part 5 Chapter 5 Section 1

Object

Documentation type

Additional description

Info

cargo tank cleaning system

S010 – Piping diagram (PD)

Shall also include arrangements for cleaning of cargo piping and shall include water supply and discharge piping.

AP

cargo tank gas freeing system

S010 – Piping diagram (PD)

Shall also include arrangements for gas freeing of cargo piping.

AP

AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

4.1.3 For general requirements for documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. 4.1.4 For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 4.1.5 Other plans, specifications or information may be required depending on the arrangement and the equipment used in each separate case.

4.2 Certification requirements 4.2.1 General Products shall be certified as required in Table 7. Table 7 Certification requirements Object

Certificate type

Issued by

PC

Society

MC

Manufacturer

PC

Society

MC

Manufacturer

P/V-valves and other flame arresting elements

TA

Society

cargo pumps

PC

Society

cargo tanks gas-freeing fans

PC

Society

ventilation fans for hazardous areas

PC

Society

hydrocarbon gas detection and alarm system, fixed

PC

Society

cargo valves and pumps control and monitoring system

PC

Society

cargo tanks level monitoring system

PC

Society

cargo tanks overflow protection alarm system

PC

Society

cargo tanks pressure monitoring alarm system

PC

Society

emergency towing strongpoints

emergency towing fairleads

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Certification standard*

Additional description

Including stripping pumps.

Permanently installed fans.

If required as a secondary mean of cargo tank venting as per Sec.5.

Page 20

Part 5 Chapter 5 Section 1

Object

Certification standard*

Certificate type

Issued by

Additional description

cargo tank temperature monitoring system

PC

Society

If required by Sec.4 [4.4].

portable cargo tank oil and water interface detection system

TA

Society

See Sec.9.

portable gas detectors

TA

Society

See Sec.9.

inert gas blowers

PC

Society

inert gas generators

PC

Society

scrubbers

PC

Society

deck water seals

PC

Society

scrubber sea water supply pumps

PC

Society

deck water seal sea water supply pumps

PC

Society

liquid pressure/vacuum breakers

PC

Society

pressure/vacuum valves

TA

Society

inert gas control and monitoring system

PC

Society

Associated electric equipment (motors, switchgear and control gear and frequency converters) serving an item that is required to be delivered with a product certificate issued by the Society is regarded as important equipment, and shall be certified as required by Pt.4 Ch.8 Sec.1 [2.3.2]. *Unless otherwise specified the certification standard is the Society's rules. For a definition of the certificate types, see Pt.1 Ch.3 Sec.5. For EEA flagged ships, EC-MED may be required for inert gas components, fixed hydrocarbon gas detection and alarm systems and portable gas detectors, PV valves and other flame arresting elements.

4.2.2 For general certification requirements, see Pt.1 Ch.3 Sec.4. 4.2.3 For a definition of the certificate types, see Pt.1 Ch.3 Sec.4 and Pt.1 Ch.3 Sec.5.

5 Testing 5.1 Testing during newbuilding 5.1.1 Survey requirements for inert gas systems are given in Sec.11 [6.1]. 5.1.2 Testing requirements for materials of strong points for emergency towing are given in Sec.2 [2.2]. 5.1.3 Testing requirements for cargo piping are given in Sec.4 [3.2.10] and Sec.4 [3.4]. 5.1.4 Testing requirements for flame arresting elements in gas outlets and air inlets for cargo tanks are given in Sec.5 [2.2.12]. 5.1.5 Testing requirements for electrical installations are given in Sec.8 [4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 21

Part 5 Chapter 5 Section 1

Object

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Part 5 Chapter 5 Section 1

5.1.6 Testing requirements for inert gas systems are given in Sec.11 [6.2].

Page 22

1 General 1.1 Application 1.1.1 Requirements with respect to strength of the hull structure and selection of hull materials shall follow the requirements and principles given in Pt.3, supplemented by the requirements given in this section. For scantlings and testing of tanks other than integral tanks, see Ch.7 Sec.5. 1.1.2 The additional notation CSR is mandatory for tankers and combination carriers with class notation Tanker for oil or Tanker for oil products and with L ≥ 150 m. This includes combination carriers and chemical tankers with L ≥ 150 m, also intended for carriage of oil. The CSR notation documents that the newbuilding is designed and built according to common structural rules for double hull oil tankers as described in [1.2].

1.2 Common structural rules 1.2.1 The common structural rules for bulk carriers and oil tankers define the scantling requirements for oil tankers contracted July 2015. and comprises the scantling requirements for the classification of new tankers. 1.2.2 Requirements given in [2], [3] and [4] do not apply for vessels with CSR notation. 1.2.3 Requirements given in Pt.3 Ch.1 to Pt.3 Ch.13 are covered by the common structural rules and are not applicable for vessels with CSR notation. Pt.3 Ch.14 and Pt.3 Ch.15 apply also to CSR notation. 1.2.4 For parts of the structure for which the common structural rules do not apply, the appropriate classification rules shall be applied. In cases where the common structural rules do not address certain aspects of the ship's design, the applicable classification rules shall be applied. 1.2.5 Combination carriers with class notation Bulk carrier or Tanker for oil ESP, or Ore carrier or Tanker for oil ESP shall fulfil design requirements for bulk carrier or ore carrier in addition to the common structural rules for double hull oil tankers. 1.2.6 For ships of GT ≥500 with notation CSR, access to and within spaces in, and forward of, the cargo area shall comply with SOLAS Regulation II-1/3-6 and IACS UI SC191.

2 Hull strength 2.1 Vertically corrugated bulkhead without stool 2.1.1 For ships having a moulded depth less than 16 m, vertically corrugated bulkhead may extend to inner bottom, otherwise a lower stool shall be fitted. 2.1.2 The inner bottom and hopper tank plating in way of corrugations shall be of at least the same material yield strength as the attached corrugation. Z-grade steel in accordance with Pt.2 Ch.2 Sec.2 [6] shall be used or through thickness properties shall be documented. Brackets shall be arranged below inner bottom and hopper tank plating in line with corrugation webs as far as practicable.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 23

Part 5 Chapter 5 Section 2

SECTION 2 HULL

2.2.1 Tankers of 20 000 dwt and above, including oil tankers, chemical tankers and gas carriers shall be fitted with an emergency towing arrangement in accordance with IMO resolution MSC.35(63). 2.2.2 An arrangement drawing specified in Pt.3 Ch.1 Sec.3 [2.2], which includes details of towing pennant, chafing chain and pick-up gear, shall be submitted for approval. Towing arrangements shall be arranged both forward and aft. Supports shall be adequate for towing angles up to 90° from the ship's centreline to both port and starboard and 30° vertically downwards. 2.2.3 Emergency towing arrangements shall have a working strength (SWL) of: — 1 000 kN for vessels less than 50 000 dwt — 2 000 kN for vessels of 50 000 dwt and above. The minimum breaking load (MBL) of the major components of the towing arrangements, as defined in MSC.35(63), shall be two (2) times the SWL. 2.2.4 The strong point and supporting structure for the towing arrangement shall be designed for a load of twice the SWL with allowable stresses as follows: Normal stresses:

1.00 Reh

Shear stresses:

0.58 Reh

The capacity of the structure to resist buckling failure shall be assured with acceptance criteria as given in Pt.3 Ch.8 Sec.1 Table 3 for AC-II. Guidance note: These requirements should be assessed using a simplified engineering analysis based on elastic beam theory, two dimensional grillage or finite element analysis using gross scantlings. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.5 Material of welded parts used in the strong point shall be Charpy V-notch tested (minimum 27 J at 0°C), see Pt.2 Ch.1 Sec.3. 2.2.6 The pick-up gear shall be a floating line of minimum length 120 m and with a minimum breaking load (MBL) of 200 kN. 2.2.7 Emergency towing components shall be certified as required by Sec.1 Table 7.

3 Fatigue assessment 3.1 General 3.1.1 These requirements apply to oil tankers with length above 90 m and ship types given in Ch.6, chemical tankers, with length above 90 m. 3.1.2 The fatigue strength calculations shall be carried out for the following locations: — longitudinal stiffener end connections in midship area — lower hopper knuckle connections forming boundary of inner skin amidships.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 24

Part 5 Chapter 5 Section 2

2.2 Emergency towing

— fully loaded condition, departure — normal ballast condition, arrival.

3.2 Longitudinals in way of end-supports Longitudinals end connections on outer shell shall be subject to fatigue evaluation according to Pt.3 Ch.9 and DNVGL-CG-0129 Fatigue assessment of ship structure.

3.3 Lower hopper knuckle 3.3.1 The fatigue strength of the knuckle between inner bottom and hopper plate shall be evaluated according to Pt.3 Ch.9 and to DNVGL-CG-0129 Fatigue assessment of ship structure. Guidance note: The calculation scope should normally cover one transverse frame in the midship area. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.3.2 The fatigue calculation required in [3.3.1] may be omitted for knuckles with proper support. Guidance note: To have proper support of the knuckle, brackets should be fitted in ballast tanks in line with the inner bottom. Geometrical eccentricity in the knuckle should be avoided or kept to a minimum. In addition, one of the following structural solutions for knuckles with angles between inner bottom and hopper plate between 30° and 75°, should be adequate: a)

Bracket inside cargo tank. The bracket should extend approximately to the first longitudinals and the bracket toe should have a soft nose design.

b)

Insert plate of 2.0 times the thickness normally required. Insert plates should be provided in inner bottom, hopper plate, and web frame. The insert plates should extend approximately 400 mm along inner bottom and hopper plate, approximately 800 mm in longitudinal direction, and 400 mm in the depth of the web. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4 Direct strength calculations 4.1 General 4.1.1 Requirements given in this subsection apply to oil tankers and ship types given in Ch.6, chemical tankers. 4.1.2 A simplified engineering analysis based on elastic beam theory, two dimensional grillage or finite element analysis shall be carried out to demonstrate that the stresses are acceptable when the structure is loaded as described in [4.2]. 4.1.3 Calculations as mentioned in [4.1.2] shall be carried out for: — — — —

transverse, horizontal and vertical girders in cargo tanks bulkhead structures double bottom structures other structures as deemed necessary by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 25

Part 5 Chapter 5 Section 2

3.1.3 The following two loading conditions shall be taken into account:

4.2.1 Requirements given in this subsection apply to ships with length above 90 m. 4.2.2 Cargo hold finite element analysis shall be carried out for midship region according to requirements given in Pt.3 Ch.7 Sec.3. 4.2.3 Local fine mesh analysis shall be carried out: — for laterally loaded local stiffeners and their connected brackets, subject to relative deformation between supports in the midship region according to requirements given in Pt.3 Ch.7 Sec.4 — for a connection of the corrugation and lower supporting structure to inner bottom if no lower stool is fitted. 4.2.4 Finite element analysis shall be based on loading conditions as described in [4.3]. Hull girder loads shall be included. Guidance note: FE modelling procedures are given in DNVGL-CG-0127 Sec.3. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.2.5 Analysis criteria in partial ship FE analysis Analysis criteria in partial ship analysis are given in Pt.3 Ch.7 Sec.3 [4]. In addition, for a vertically corrugated bulkhead where lower stool is not fitted, coarse mesh allowable yield and buckling utilization factor are given in Table 1. Table 1 Permissible coarse mesh permissible yield utilization factor λperm and allowable buckling utilization factor ηall for a vertically corrugated bulkhead where lower stool is not fitted Structural member supporting structure in way of lower end of 1) corrugated bulkheads without lower stool corrugation of vertically corrugated bulkheads without lower stool under lateral pressure from liquid loads and without lower stool, for shell elements only 1)

Acceptance criteria

Load components

λperm

ηall

AC-I

S

0.72

0.72

AC-II

S+D

0.90

0.90

AC-I

S

0.65

0.65

AC-II

S+D

0.81

0.81

Supporting structure for a transverse corrugated bulkhead refers to the structure in the longitudinal direction within half a web frame space forward and aft of the bulkhead, and within a vertical extent equal to the corrugation depth. Supporting structure for a longitudinal corrugated bulkhead refers to the structure in the transverse direction within 3 longitudinal stiffener spacings from each side of the bulkhead, and within a vertical extent equal to the corrugated depth.

4.2.6 Analysis criteria in fine mesh analysis Analysis criteria in fine mesh analysis are given in Pt.3 Ch.7 Sec.4 [4]. Where a lower stool is not fitted to a vertically corrugated bulkhead, the permissible stresses given in Pt.3 Ch.7 Sec.4 [4.2.2] shall be reduced by 10% for the areas under investigation by fine mesh analysis.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 26

Part 5 Chapter 5 Section 2

4.2 Direct strength calculations for ships with length above 90 m

4.3.1 The girder structure in the cargo region shall generally be considered for the load conditions given in [4.3.2] and [4.3.3]. These loading conditions shall be based on the actual design, considering possible combinations of tank filling and draught. 4.3.2 Load conditions following the principles below shall be examined for upright seagoing conditions: a) b) c)

any cargo tank to be empty on full draught (T) with adjacent cargo tanks full any cargo tank to be filled on a minimum relevant seagoing draught (TA) with the adjacent tanks empty all cargo tanks within a transverse section of the ship to be filled on minimum relevant seagoing draught (TA) with adjoining cargo tanks forward and aft empty.

4.3.3 Load conditions following the principles below shall be examined for upright harbour conditions: a) b)

any cargo tank may be filled on a draught of 0.25 D (0.35 T if this is less) with adjacent tanks empty all cargo tanks in a section of the ship to be filled at a draught of 0.35 D (0.5 T if this is less) with adjoining cargo tanks forward and aft empty.

4.3.4 Girders on transverse bulkheads in ships with 1 or 2 longitudinal bulkheads shall additionally be considered for alternate loading of the cargo tanks. In this condition a draught of TA shall be applied. 4.3.5 Ships with two (2) longitudinal bulkheads and with cross ties in the centre tank shall be considered for an asymmetric load condition with one wing tank filled and other tanks empty, where such loading pattern is included in the ship loading manual for seagoing conditions. If loading patterns is not considered, an operational restriction describing that the difference in filling level between corresponding port and starboard wing cargo tanks shall not exceed 25% of the filling height in the wing cargo tank, shall be added in the loading manual.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 27

Part 5 Chapter 5 Section 2

4.3 Load conditions

1 Intact stability The intact stability requirements of Pt.3 Ch.15 shall be complied with. In addition, vessels with class notation Tanker for Oil of 5000 dwt and above shall comply with the intact stability criteria as specified in MARPOL Annex I, Reg. 27.

2 Location and separation of spaces 2.1 General 2.1.1 Machinery space shall be isolated from cargo tanks and slop tanks by cofferdams, pump rooms, oil fuel bunker tanks or ballast tanks. Spaces which may be approved as cofferdams, see [6.1]. 2.1.2 Fuel oil bunker tanks shall not be situated within the cargo tank block. Such tanks may, however, be situated at forward and aft end of the cargo tanks instead of cofferdams. Fuel oil tanks shall not extend fully nor partly above or beneath cargo or slop tanks and are not permitted to extend into the protective area of cargo tanks required by [3]. 2.1.3 Machinery and boiler spaces and accommodation and service spaces shall be positioned aft of the cargo area, but not necessarily aft of fuel oil tanks. Note: Machinery spaces should not be located fully nor partly within the cargo area including within e.g. pumprooms or other spaces approved as cofferdams, except as specified in [2.1.4]. Machinery spaces other than those of category A that contain electrically driven equipment or systems required for cargo handling may upon special considerations be accepted located within the cargo area. Area classification requirements apply. Examples of such systems are: hydraulic power units for cargo systems, nitrogen generators and dehumidification plants. ---e-n-d---o-f---n-o-t-e---

2.1.4 The lower portion of the cargo pump room may be recessed into machinery and boiler spaces to accommodate pumps, provided the deck head of the recess is in general not more than one-third of the moulded depth above the keel. For ships of not more than 25 000 tons deadweight, where it is demonstrated that for reasons of access and satisfactory piping arrangements this is impracticable, a recess in excess of such height may be permitted, though not exceeding one half of the moulded depth above the keel. 2.1.5 Spaces mentioned in [2.1.3] except machinery spaces of category A, may be positioned forward of the cargo area after consideration in each case. Guidance note: Machinery spaces other than those of category A may be accepted located in forecastle spaces above forepeak tanks even if said forepeak tank is located adjacent to a cargo tank. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.6 Where bow thruster spaces are defined as other machinery space, they shall not be located adjacent to cargo tanks (SOLAS Ch.II-2 Reg.4.5.1.3). 2.1.7 Where the fitting of a navigation position above the cargo area is shown to be necessary, it shall be separated from the cargo tank deck by means of an open space with a height of at least 2 m.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 28

Part 5 Chapter 5 Section 3

SECTION 3 SHIP ARRANGEMENT AND STABILITY

2.1.9 Where a corner-to-corner situation occurs between a non-hazardous space and a cargo tank, a small enclosed space (cofferdam) created by a diagonal plate across the corner on the non-hazardous side, may be accepted as separation. 2.1.10 Paint lockers shall not be located within the cargo tank block, but may be located above oil fuel bunker tanks or ballast tanks aft of the cargo tanks/slop tanks.

2.2 Arrangements of barges The spaces forward of the collision bulkhead (forepeak) and aft of the aftermost bulkhead (afterpeak) shall not be arranged as cargo oil tanks.

3 Tank and pump room arrangement 3.1 Segregated ballast tanks 3.1.1 Ships of 20 000 tons deadweight and above having the class notation Tanker for oil and ships of 30 000 tons deadweight and above with class notation Tanker for oil products shall have segregated ballast tanks. The capacity of segregated ballast tanks shall be at least such that, in any ballast condition at any part of the voyage, including the conditions consisting of lightweight plus segregated ballast only, the ship's draughts and trim can meet each of the following requirements: a)

the moulded draught amidships (dm) in metres (without taking into account any ship's deformation) shall not be less than: dm = 2.0 + 0.02 LF

b) c)

where LF is the length of the ship as defined by MARPOL. the draughts at the forward and after perpendiculars shall correspond to those determined by the draught amidships (dm) as specified in subparagraph a) of this paragraph, in association with the trim by the stern of not greater than 0.015 LF; and in any case the draught at the after perpendicular shall not be less than that which is necessary to obtain full immersion of the propeller(s).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 29

Part 5 Chapter 5 Section 3

2.1.8 Deck spills shall be kept away from accommodation and service areas and from discharge into the sea by a permanent continuous coaming of minimum 100 mm high surrounding the cargo deck. In the aft corners of the cargo deck the coaming shall be at least 300 mm high and extend at least 4.5 m forward from each corner and inboard from side to side. Scupper plugs of mechanical type are required. Means of draining or removing oil or oily water within the coamings shall be provided.

3.2.1 Ships of 600 tons deadweight but less than 5 000 tons deadweight shall have a double hull arrangement covering the entire cargo tank length with particulars as follows:

a)

Double side width (m): or w = 0.76 whichever is the greater.

DW b)

= deadweight capacity of ship in metric tons. 3

Tankers where each cargo tank does not exceed 700 m may be designed with single side. Ships intended for carriage of heavy grade oil (as defined in MARPOL Annex I, Reg. 21) as cargo, shall comply with a).

c)

Double bottom height (m): or h = 0.76 whichever is the greater.

3.2.2 Ships of 5 000 tons deadweight and above shall have double hull in the entire cargo tank length with arrangement as follows:

a)

Double side width (m): or w = 2.0 whichever is the lesser, but not less than 1.0 m.

b)

Double bottom height (m): or h = 2.0 whichever is the lesser, but not less than 1.0 m.

When the distances h and w are different, the distance w shall have preference at levels exceeding 1.5 h above the baseline as shown in Figure 1.

w

w

w w

h<w

h>w

h

h

1.5 h

h

h base line

Figure 1 Double hull distances

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 30

Part 5 Chapter 5 Section 3

3.2 Protection of cargo tanks

f hc ρcg + 100 δ p ≤ dn ρsg where:

hc ρc dn ρs δp f g

= height of cargo in contact with the bottom shell plating in metres 3

= maximum cargo density in t/m

= minimum operating draught under any expected loading condition in metres 3

= density of seawater in t/m

= maximum set pressure of pressure/vacuum valve provided for the cargo tank in bars = safety factor = 1.1

2

= standard acceleration of gravity (9.81 m/s ).

Any horizontal partition necessary to fulfil the above requirements shall be located at a height of not less than B/6 or 6 m, whichever is the lesser, but not more than 0.6 D, above the baseline where D is the moulded depth amidships. The location of wing tanks or spaces shall be as defined in [3.2.2] except that below a level 1.5 h above the baseline where h is as defined in [3.2.2] the cargo tank boundary line may be vertical down to the bottom plating. 3.2.4 Suction wells in cargo tanks may protrude into the double bottom below the boundary line defined by the distance h provided that such wells are as small as practicable and the distance between the well bottom and bottom shell plating is not less than 0.5 h. Guidance note: For combined oil and chemical tankers, the requirements for the suction well in Ch.6 Sec.3 [1.1] are stricter. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.3 Cargo tanks and slop tanks 3.3.1 Accidental oil outflow performance in the case of side damage and bottom damage shall be within the limits required in MARPOL Annex I, Reg. 23. 3.3.2 Oil tankers of 150 GT and above shall be provided with arrangements of slop tank or combination of slop tanks with a total capacity complying with MARPOL Annex I, Reg. 29. 3.3.3 Oil tankers of 70 000 tons deadweight and above shall be provided with at least two slop tanks. 3.3.4 Slop tanks shall be designed particularly with respect to decantation purpose. Positions of inlets, outlets, baffles or weirs where fitted, shall be placed so as to avoid excessive turbulence and entrainment of oil or emulsion with the water.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 31

Part 5 Chapter 5 Section 3

3.2.3 Double bottom tanks or spaces as required by [3.2.1] may be dispensed with, provided that the design of the tanker is such that the cargo and vapour pressure exerted on the bottom shell plating forming a single boundary between the cargo and the sea does not exceed the external hydrostatic water pressure, as expressed by the following formula:

Pump rooms containing cargo pumps in ships of 5 000 tons deadweight and above, shall be provided with a double bottom with depth h as follows: (m) or h = 2.0 m, whichever is lesser, but not less than 1.0 m.

4 Arrangement of access and openings to spaces and tanks 4.1 Accommodation and non-hazardous spaces 4.1.1 Entrances, air inlets and openings to accommodation spaces, service spaces, control stations and machinery spaces shall not face the cargo area. They shall be located on the end bulkhead or on the outboard side of the superstructure or deckhouse at a distance of at least L/25 but not less than 3 m from the end of the superstructure or deckhouse facing the cargo area. This distance, however, need not exceed 5 m. Within the limits specified above, the following apply: a) b) c)

Bolted plates for removal of machinery may be fitted. Such plates shall be insulated to A-60 class standard. Signboards giving instruction that the plates shall be kept closed unless the ship is gas-free, shall be posted on board. Wheelhouse windows may be non-fixed and wheelhouse doors may be located within the above limits as long as they are so designed that a rapid and efficient gas and vapour tightening of the wheelhouse can be ensured. Windows and side scuttles shall be of the fixed (non-opening) type. Such windows and side scuttles except wheelhouse windows, shall be constructed to A-60 class standard.

4.1.2 Cargo control rooms, stores and other spaces not covered by [4.1.3] but located within accommodation, service and control stations spaces, may be permitted to have doors facing the cargo area. Where such doors are fitted, the spaces are not to have access to the spaces covered by [4.1.3] and the boundaries of the spaces shall be insulated to A-60 class. 4.1.3 For access and openings to non-hazardous spaces other than accommodation and service spaces, the following provisions apply: — entrances shall not be arranged from hazardous spaces — entrances from hazardous areas on open deck shall normally not be arranged. If air locks are arranged such entrances may, however, be approved, see [4.1.5] and [4.1.6] — entrances to non-hazardous forecastle spaces from hazardous areas shall be arranged with air locks, see [4.1.4]. 4.1.4 Ventilation inlets for the spaces mentioned in [4.1.1] shall be located as far as practicable from gasdangerous zones, and in no case are the ventilation inlets nor outlets to be located closer to the cargo area than specified for doors in [4.1.1]. 4.1.5 Entrance through air locks to non-hazardous spaces shall be arranged at a horizontal distance of at least 3 m from any opening to a cargo tank or hazardous space containing gas sources, such as valves, hose connections or pumps used with the cargo.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 32

Part 5 Chapter 5 Section 3

3.4 Double bottom in pump rooms

a) b) c)

Air locks shall be enclosed by gastight steel bulkheads with two substantially gas tight self-closing doors spaced at least 1.5 m and not more than 2.5 m apart. The door sill height shall comply with the requirement given in Pt.3 Ch.12 Sec.2 [5], but shall not be less than 300 mm. Air locks shall have a simple geometrical form. They shall provide free and easy passage, and shall have 2 a deck area not less than about 1.5 m . Air locks shall not be used for other purposes, for instance as store rooms. For requirements to ventilation of airlocks, see Sec.6.

4.2 Access to and within hazardous spaces 4.2.1 Access to and within spaces in, and forward of, the cargo area shall comply with SOLAS Regulation II-1/3-6. 4.2.2 Doors to hazardous spaces, situated completely upon the open deck, shall have as low a sill height as possible. Such compartments shall not be connected with compartments at a lower level. 4.2.3 For deck openings for scaffolding wire connections, the number and position of holes in the deck are subject to approval. The closing of the holes may be effected by screwed plugs of metal or an acceptable synthetic material, see Sec.4 [1]. The material used in the manufacture of plugs and jointing, if any, shall be impervious to all cargoes intended to be carried. Metal plugs shall have a fine screw thread to ensure an adequate number of engaging threads. A number of spare plugs equal to at least 10% of the total number of holes shall be kept on board.

5 Protection of crew 5.1 Arrangement 5.1.1 Guard rails, bulwarks and arrangements for safe access to bow shall be arranged in accordance with Pt.3 Ch.11 Sec.3 [3]. On tank deck open guard rails shall normally be fitted. Plate bulwarks, with a 230 mm high continuous opening at lower edge, may be accepted upon consideration of the deck arrangement and probable gas accumulation. Guidance note: Permanently constructed gangways for safe access to bow should be of substantial strength and be constructed of fire resistant and non-slip material. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.1.2 Systems with a surface temperature above 60°C shall be provided with insulation or mechanical shielding if they are so located that crew may come in contact with them during normal operation or access.

6 Cofferdams, pipe tunnels and deck trunks 6.1 Cofferdams 6.1.1 Cofferdams shall be of sufficient size for easy access to all parts, and they shall cover the entire adjacent tank bulkhead. Minimum distance between bulkheads (and requirements to sizes of openings) shall be in accordance with [4.2], however not less than 600 mm.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 33

Part 5 Chapter 5 Section 3

4.1.6 Air locks shall comply with the following requirements:

6.1.3 Pump rooms and ballast tanks will be accepted as cofferdams. Ballast tanks will, however, not be accepted as cofferdams for protected slop tanks. See Sec.12.

6.2 Pipe tunnels and deck trunks 6.2.1 Pipe tunnels shall have ample space for inspection of the pipes. 6.2.2 The pipes in pipe tunnels shall be situated as high as possible above the ship's bottom. There shall be no connection between a pipe tunnel and the engine room either by pipes or manholes. 6.2.3 Provision shall be made for at least two exits to the open deck arranged at a maximum distance from each other. One of these, fitted with a watertight closure, may lead to the cargo pump room. 6.2.4 Where there is permanent access from a pipe tunnel to the main pump-room, a watertight door shall be fitted complying with the requirements of SOLAS Ch. II-1/25-9, and in addition with the following requirements: a) b)

In addition to bridge operation, the watertight door shall be capable of being manually closed from outside the main pump-room entrance. The watertight door shall be kept closed during normal operations of the ship except when access to the pipe tunnel is required.

6.2.5 Deck trunks containing liquid cargo and cargo vapour piping systems shall comply with IMO MSC/Circ. 1276. Deck trunks containing cargo pumps and/or cargo valves shall comply with the requirements to cargo pump rooms. The following shall be provided: — A fixed fire detection and extinguishing system (CO2 is acceptable). Note that the deck trunk area can be excluded from the total area used in the deck foam capacity calculations. — A fixed gas detection in accordance with Sec.9 [6]. — A fixed mechanical ventilation system with capacity of minimum 20 air-changes per hour in accordance with Sec.6. Interlock shall be arranged between ventilation and light. — A fixed bilge system, operable from outside the trunk. — Bilge level alarms shall be in accordance with Sec.9 [2.1].

7 Diesel engines for emergency fire pumps 7.1 General 7.1.1 Diesel engines for emergency fire pump, shall be installed in a non hazardous space. 7.1.2 The exhaust pipe of the diesel engine, if fitted forward of the cargo area, shall have an effective spark arrester, and shall be led out to the atmosphere outside hazardous areas.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 34

Part 5 Chapter 5 Section 3

6.1.2 Small voids adjacent to cargo tanks shall be provided with arrangements for inerting, gas-freeing and inspection from a space with equivalent hazardous area classification (other than cargo tanks) or open deck. See also [2.1.9].

8.1 General 8.1.1 The chain locker shall be arranged as a non hazardous space. 8.1.2 Windlass cable lifters and chain pipes shall be situated outside hazardous areas.

9 Equipment in tanks and cofferdams Anodes, washing machines and other permanently attached equipment units in tanks and cofferdams shall be securely fastened to the structure. The units and their supports shall be able to withstand sloshing in the tanks and vibratory loads as well as other loads which may be imposed in service. Guidance note: When selecting construction materials in permanently attached equipment units in tanks and cofferdams, due consideration should to be paid to the contact spark-producing properties. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

10 Surface metal temperatures in hazardous areas Surface metal temperatures of equipment and piping in hazardous areas shall not exceed 220°C.

11 Signboards 11.1 References Signboards are required by the rules in: — [4.1.1] regarding plates bolted to boundaries facing the cargo area and which can be opened for removal of machinery. These shall be supplied with signboards giving instruction that the plates shall be kept closed unless ship is gas-free. — Sec.8 [6.1.1] regarding opening of a lighting fitting. Before opening its supply circuit shall be disconnected. — Sec.8 [6.1.2] regarding spaces where the ventilation shall be in operation before the lighting is turned on. — Sec.8 [6.1.3] regarding portable electrical equipment supplied by flexible cables. This equipment shall not be used in areas where there is gas danger. — Sec.8 [6.1.4] regarding welding apparatus. These shall not be used unless the working space and adjacent spaces are gas-free. — Sec.10 [2.2.4] regarding access to stool tanks. — Sec.12 [3.1.1] regarding hatches and other openings to cargo slop tanks. These shall be kept closed and locked during handling of dry cargo. — Sec.12 [3.1.2] regarding instructions for handling of slop.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 35

Part 5 Chapter 5 Section 3

8 Chain locker and anchor windlass

1 Piping materials 1.1 Selection and testing 1.1.1 Materials shall generally be selected according requirements given in Pt.4 Ch.6 for piping materials. The selected materials shall be tested according to regulations in Pt.2. 1.1.2 Other materials may be accepted after special consideration. 1.1.3 Synthetic materials for components and piping shall be approved in each separate case.

1.2 Special requirements for cargo piping system 1.2.1 Manifold valves and distance pieces or reducers outboard of valves, which are connected directly to the cargo pipeline's shore connection on deck, shall be made of steel and fitted with flanges conforming to ASME B16.5, i.e. be of flanged type or fully-lugged type.

1.3 Plastic pipes in cargo area 1.3.1 Plastic pipes of approved type and tested according to an approved specification may be accepted. For the application of plastic pipes, see Pt.4 Ch.6. 5

1.3.2 When used in a hazardous area, the surface resistance per unit length of pipes shall not exceed 10 Ω/ 6 m and the resistance to earth from any point in the piping system shall not exceed 10 Ω.

1.4 Aluminium coatings 1.4.1 Aluminized pipes are generally accepted in non-hazardous areas and may be permitted in hazardous areas on open deck and in inerted cargo tanks and ballast tanks, provided the pipes are protected from accidental impact.

2 Piping systems not used for cargo oil 2.1 General 2.1.1 There shall be no connection between piping systems in the cargo area and piping systems in the remainder of the ship, unless explicitly specified in this section. Guidance note: Piping systems for e.g. hydraulic oil, fuel lines, compressed air, steam and condensate, fire and foam located in the cargo area are permitted connected to systems in the remainder of the ship, provided they are not permanently connected to cargo handling systems or have open ends in cargo tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.2 Piping systems such as compressed air, hydraulic oil which serve systems within tanks or spaces that are not used for cargo shall not be led through cargo tanks.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 36

Part 5 Chapter 5 Section 4

SECTION 4 PIPING SYSTEMS IN CARGO AREA

2.1.4 In general all piping led from machinery spaces into the cargo area shall be provided with means to preserve the integrity of the machinery space bulkhead. 2.1.5 Piping system with an open end in machinery spaces or in hazardous spaces in the cargo area and piping led from machinery spaces to the cargo area shall be led above main deck. This also applies to ballast water treatment system piping (IACS UR M74). Guidance note: For closed piping system without open ends, pipe penetrations may be accepted in the ER bulkhead if readily accessible isolation valves are provided in the machinery space close to the bulkhead. The penetrations should be located as high as possible. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.6 Pipe penetrations shall be as per Pt.4 Ch.6 Sec.3 [1.4] and type approved according to DNVGL-CP-0165.

2.2 Drainage of pump rooms, cofferdams, pipe tunnels, ballast and fuel oil tanks 2.2.1 Cargo pump rooms shall have a bilge system connected to pumps or bilge ejectors. The bilge system shall be capable of being operated from outside the cargo pumproom. 2.2.2 Cargo pumps may be used for bilge service provided each bilge suction pipe is fitted with a screwdown non-return valve, and an additional stop valve is fitted to the pipe connection between pump and the non-return valve. 2.2.3 The bilge pipes in the cargo pump room shall not be led into the engine room. 2.2.4 Cofferdams, pipe tunnels, voids and other dry-compartments below main deck and within the cargo area shall be provided with bilge suctions. Guidance note: For small voids, with direct access from open deck (e.g. transverse upper stool spaces), portable draining arrangements may be accepted. Arrangements where the use of the portable drainage equipment requires entry into the void will not be accepted. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.5 Hazardous spaces (including any compartment or tank, cofferdams or void) within the cargo area shall only be drained by bilge pumps or ejectors located within the space itself or within a space with an equivalent hazard. 2.2.6 Pipe tunnels shall be drained from the cargo pump room or an equivalent hazardous space. 2.2.7 Segregated ballast tanks within the cargo area shall be served by ballast pumps in the cargo pump room, in a similar hazardous space or inside ballast tanks. Ballast tanks shall be provided with at least two drain pumping units. At least one of the pumps shall be exclusively used for ballast. As another means an eductor or an emergency connection to a cargo pump may be accepted. Segregated ballast systems shall not have any connections to the cargo system, but an emergency discharge of ballast water may be arranged by connection to a cargo pump. The connection pipe shall be provided with a removable spool piece and a closing valve and non-return valve in series in the suction side to the cargo oil pump.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 37

Part 5 Chapter 5 Section 4

2.1.3 For ships not carrying homogeneous cargoes, e.g. crude oil, piping systems such as hydraulic oil serving systems within cargo tanks, shall be led to tanks from deck level and not penetrate boundaries between cargo tanks and tanks and compartments that do not contain cargo.

2.2.9 A discharge manifold for connection to reception facilities for the discharge of dirty ballast water or oil contaminated water shall be located on the open deck on both sides of the ship. 2.2.10 For ships arranged with emergency connection between the cargo system and the segregated ballast system as specified in [2.2.7], the discharge manifold required by [2.2.9] may be omitted. 2.2.11 Ballast tanks forward of cargo area may be connected to the ballast pumps in the aft cargo pump room, see [2.2.13]. 2.2.12 Ballast piping and other piping such as sounding and vent piping to ballast tanks shall not pass through cargo tanks. 2.2.13 For requirements to drainage of ballast tanks, see Pt.4 Ch.6 Sec.4 [9]. 2.2.14 Fuel oil bunker tanks adjacent to cargo tanks may be connected directly to pumps in the engine room. The pipes shall not pass through cargo tanks and shall have no connection with pipelines serving such tanks. 2.2.15 Ballast water treatment systems shall comply with safety requirements of Pt.6 Ch.7 Sec.1.

2.3 Fore peak ballast tank 2.3.1 The fore peak tank can be ballasted with the system serving other ballast tanks within the cargo area, provided: — The fore peak tank is considered as hazardous. — The air pipes shall be located on open deck. The hazardous zone classification in way of air pipes shall be in accordance with Sec.8. — Means are provided, on the open deck and within tanks, to allow measurement of flammable gas concentrations within the fore peak tank by a suitable portable instrument. — Arrangements for sounding, gas detection and other openings to the fore peak tank are direct from open deck. — The access to the fore peak tank is direct from open deck. As an alternative to direct access from open deck, indirect access to the fore peak tank through an enclosed space may be accepted provided that: — In case the enclosed space is non-hazardous and separated from the cargo tanks by cofferdams, the access is through a gas tight bolted manhole located in the enclosed space and a signboard shall be provided at the manhole stating that the fore peak tank may only be opened after it has been proven to be gas free or any electrical equipment which is not certified safe in the enclosed space is isolated. — In case the enclosed space has a common boundary with the cargo tanks and is therefore hazardous, the enclosed space is well ventilated to open deck and a signboard is provided at the manhole(s) stating that the forepeak may only be opened when the enclosed space is being thoroughly ventilated. (IACS UR F44 Rev.1) 2.3.2 The requirements in [2.3.1] also apply to spaces other than forepeak tanks, such as upper forward voids spaces, with common boundary with cargo tanks and located below non-hazardous enclosed spaces (e.g. forecastle spaces) and without access to open deck. In order to comply with the condition that the space can be well ventilated, adequate gas-freeing arrangements shall be provided. For forepeak tanks or other ballast tanks adequate gas-freeing to open deck is ensured through filling and emptying the tank. For

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 38

Part 5 Chapter 5 Section 4

2.2.8 Arrangements for discharge of water ballast and oil contaminated water from the cargo area shall be made above the waterline in the deepest ballast condition, in accordance with MARPOL Annex I, Reg.30.

2.4 Oil discharge monitoring and control systems 2.4.1 Oil tankers of 150 GT and above shall be equipped with an approved arrangement for oil content monitoring of oily ballast and tank washing water in accordance with MARPOL Annex I, Reg. 31. The system shall record continuously the discharge of oil in litres per nautical mile and total quantity of oil discharged, or the oil content and rate of discharge. 2.4.2 An instruction and operation manual describing all essential procedures for manual and automatic operations shall be submitted for approval in accordance with Sec.1 Table 5. Guidance note: Reference is made to IMO MEPC.108(49) as amended by MEPC.240(65) - Revised Guidelines and Specifications for Oil Discharge Monitoring and Control Systems for Oil Tankers. IMO Res. MEPC240(65) is applicable to ships that intend to carry bio-fuel blends. Manufacturer recommended spares for the ODME should be carried to ensure the operation of the equipment. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.4.3 Oil tankers of 150 GT and above, shall be provided with an effective oil and water interface detector of approved type in accordance with MARPOL Annex I, Reg. 32, for determination of the oil water inter face in slop tanks and other tanks where separation of oil and water is effected and from which it is intended to discharge effluent direct to sea.

2.5 Oil record book, shipboard oil pollution emergency plan and ship-toship transfer 2.5.1 Oil tankers of 150 GT and above shall be provided with an oil record book in accordance with MARPOL Annex I, Reg. 36. 2.5.2 Oil tankers of 150 GT and above shall be provided with a shipboard oil pollution emergency plan (SOPEP) approved by an administration in accordance with MARPOL Annex I, Reg. 37. 2.5.3 Oil tankers of 150 GT and above, which shall be engaged in transfer of oil cargo between oil tankers at sea, shall be provided with a ship-to-ship (STS) transfer manual in accordance with MARPOL Annex I, Reg. 41.

2.6 Air, sounding and filling pipes 2.6.1 Filling of tanks within cargo area shall be carried out from the cargo pump room or a similar hazardous space. 2.6.2 Filling lines to permanent ballast tanks and other discharge lines to cargo area may be connected to pumps outside the cargo area (e.g. engine room), provided the lines are not carried through cargo tanks and adjacent spaces and do not have a permanent connection to any cargo tank. The arrangement is subject to approval in each separate case. 2.6.3 Filling lines to permanent ballast tanks shall be so arranged that the generation of static electricity is reduced, e.g. by reducing the free fall into the tank to a minimum.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 39

Part 5 Chapter 5 Section 4

voids without direct access to open deck, fixed piping extending to the bottom of the void will normally be required to ensure thorough ventilation from open deck.

Guidance note: Seawater suction should be arranged at the opposite side from the discharge of ballast water from cargo tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.6.5 Cofferdams shall be provided with sounding pipes and with air pipes led to the atmosphere. The air pipes shall be fitted with flame screens at their outlets. 2.6.6 An arrangement for transferring sludge, bilge water and similar from machinery spaces to e.g. slop tank may be accepted on the following conditions: — The filling pipe is routed via deck level. — The filling pipe is provided with a closable non-return valve (or automatic non-return valve and a closable valve in series) located in the cargo area. — A spool piece or flexible hose not exceeding 2 m in length is provided on open deck. The design shall incorporate valve(s) so that when mounting or dismantling the spool piece the crew is not exposed to vapour from the slop tank. Blanks shall be provided for when the spool piece or hose is dismantled when it is not in use. — The open end in the slop tank extends to the bottom of the slop tank or with the outlet bent towards a bulkhead in a suitable location of the tank in order to prevent free fall. — Signboards with operational instructions are fitted in cargo control room and in the engine control room.

3 Cargo oil systems 3.1 General 3.1.1 A permanent system of piping and pumps shall be provided for the cargo tanks. This system shall be entirely separate from all other piping systems on board. Exemption, see Sec.5 [1]. 3.1.2 At least two independently driven cargo oil pumps shall be connected to the system. 3.1.3 In tankers where cargo tanks are equipped with independent pumps (e.g. deep well pumps), the installation of one pump per tank may be approved. Satisfactory facilities shall be provided for emptying the tanks in case of failure of the regular pump. 3.1.4 Hydraulically powered pumps, submerged in cargo tanks (e.g. deep well pumps), shall be arranged with double barriers, preventing the hydraulic system serving the pumps from being directly exposed to the cargo. The double barrier shall be arranged for detection and drainage of possible cargo leakages. 3.1.5 Cargo pumps shall be certified as required by Sec.1 Table 7. For electrically driven pumps, associated electric motors and motor starters shall be certified as required by Pt.4 Ch.8 Sec.1 Table 3. For steam driven pumps, steam turbines shall be certified in accordance with Pt.4 Ch.3. For hydraulically driven pumps, hydraulic pumps shall be certified in accordance with Pt.4 Ch.6. 3.1.6 The wall thickness of cargo pipes will be specially considered on the basis of anticipated corrosion. The thickness of the pipes shall, however, not be less than given in Pt.4 Ch.6 Sec.9 [1]. 3.1.7 Piping of all cargo handling systems shall be electrically bonded to the ship's hull. The resistance to 6 earth from any point in the piping system is not to exceed 10 Ω. Fix points may be considered as an effective bonding.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 40

Part 5 Chapter 5 Section 4

2.6.4 Suction for seawater to permanent ballast tanks shall not be arranged in the same sea chest as used for discharge of ballast water from cargo tanks, see also [3.2.8].

3.1.8 For cargo pumps designed with a separate vacuum stripping system (e.g. pumproom tankers), all vent pipes from the vacuum system shall be led to a slop tank or terminate in a safe location on open deck as to prevent crew exposure to vapour as well as water ingress in the system. Vent pipes from drain tanks shall terminate in a safe location of open deck. 3.1.9 Drainage systems from cargo deck, drip trays etc. shall be arranged for transfer to cargo or slop tanks. Connections to cargo and slop tanks shall be provided with means to prevent backflow of vapor. 3.1.10 The cargo piping system shall be dimensioned according to Pt.4 Ch.6 Sec.8. The design pressure p is the maximum working pressure to which the system may be subjected. Due consideration shall be given to possible liquid hammer in connection with the closing of valves. 3.1.11 The design pressure for cargo piping shall be 10 bar as a minimum. For ships designed for the carriage of high density cargo, the design pressure shall take into account density of such cargo. Guidance note: Maximum pressure will occur with cargo pumps running at full speed against closed manifold valves, when pumping cargo with the maximum design density (regardless of cargo tank filling limitations). As an alternative to increased design pressure when carrying high density cargo, a pressure monitoring system which automatically prevents the design pressure from being exceeded may be accepted. The system shall activate an alarm at the cargo control station. The system shall not impair the operation of ballast and bilge pumps connected to the cargo pump power supply system. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2 Cargo piping systems 3.2.1 The complete cargo piping system, except for bow and stern loading systems complying with [5], shall be located within the cargo area. 3.2.2 Valves or branch pieces, which connect the cargo pipeline's shore connection on deck, and cargo piping shall be supported with due regard to load stresses. 3.2.3 Expansion elements shall be provided in the cargo piping as necessary. 3.2.4 Means for drainage of the cargo lines shall be provided. Tankers for oil of 20 000 tons deadweight and above, and tankers for oil products of 30 000 tons deadweight and above, shall be provided with a special small diameter line, not exceeding 10% of the cross-sectional area of main cargo line, for discharge ashore. This line shall be connected outboard of the ship's manifold valves. Stripping systems for ships provided with deep well cargo pumps shall be specially considered. 3.2.5 The cargo piping system shall not have any connection to permanent ballast tanks. 3.2.6 Cargo piping and similar piping to cargo tanks shall not pass through ballast tanks or vice versa. Exemptions to this requirement may be granted for short length of pipes with heavy wall thickness, provided that they are completely welded. Guidance note: Short length of pipes may be such as through stool tanks used for ballast etc. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2.7 Filling lines to cargo tanks shall be so arranged that the generation of static electricity is reduced, e.g. by reducing the free fall into the tank to a minimum.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 41

Part 5 Chapter 5 Section 4

Piping sections not permanently connected to the hull, shall be electrically bonded to the hull by bonding straps.

3.2.9 Isolation of cargo piping connections to sea shall be made by means of at least two shut-off valves. Arrangement for tightness monitoring of sea valves shall be provided. Guidance note: —

For tankers delivered on or after 2010-01-01, MARPOL Annex I, Reg. 30.7 will apply for this arrangement.

—

For arrangement of tightness testing of sea valves, see OCIMF's recommendations Prevention of oil spillages through cargo pump room sea valves. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2.10 Where pumps in cargo room or other hazardous spaces are driven by shafting passing into the pump room through bulkheads or deck plating, gastight glands of approved type shall be fitted. The glands shall be efficiently lubricated and constructed so as to reduce the risk of overheating. Systems requiring periodic greasing type is not permitted. The glands shall be visible and easily accessible. Parts which may accidentally come into contact if the seal is badly aligned or if a bearing is damaged, shall be of such materials that no spark may occur. If an expansion bellow is fitted, it shall be hydraulically pressure tested. 3.2.11 Displacement pumps shall have relief valves with discharge to the suction line. 3.2.12 For systems served by centrifugal pumps the design pressure for the piping shall be at least equal to the highest pressure the pump may generate. Alternatively a pressure relief valve or alternative means for automatically safeguarding against overpressure shall be provided. 3.2.13 Means shall be provided for stopping the cargo pumps at the cargo manifolds and at the lower pump room level. 3.2.14 Remote control and monitoring of the cargo handling, see Sec.9. 3.2.15 All ships having a noxious liquid substances (NLS) certificate for the carriage of liquid substances as listed in the IBC code chapter 18 category Z, shall have on board a cargo record book according to MARPOL Annex II, Appendix 2.

3.3 Cargo piping systems for barges 3.3.1 The barge shall be equipped with a permanent piping system for the oil cargo. Closing valves operable from outside the tank shall be fitted to each branch pipe within the tank it serves. 3.3.2 At least two independently driven cargo pumps shall be connected to the cargo piping system. If each cargo tank is fitted with a separate cargo pump, one cargo pump per tank may be accepted. 3.3.3 For unmanned barges without auxiliary machinery, non-permanent cargo pumps with external power supply may be acceptable. The pumps shall be connected to the piping system on open deck or in a cargo pump room. 3.3.4 Cargo pump room situated below deck shall have a power operated bilge system. Cargo pump room may have bilge suctions connected to the cargo pumps.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 42

Part 5 Chapter 5 Section 4

3.2.8 The discharge of ballast water from cargo tanks shall be arranged in such a way as to prevent the ballast water from being drawn into sea suctions for other pipe systems, i.e. cooling water systems for machinery.

3.4.1 Cargo piping shall be hydrostatically tested in the presence of the surveyor to a test pressure = 1.5 × the maximum working pressure. If hydrostatic testing of separate lengths of piping valves, expansion elements etc. has been carried out prior to the installation on board, a tightness test to at least the design pressure is required after completion of the installation onboard. 3.4.2 Cargo oil pumps shall be hydrostatically tested to 1.3 times the design pressure, with a minimum of 14 bar. For centrifugal pumps the maximum pressure shall be the maximum pressure head on the headcapacity curve. For displacement pumps the design pressure shall not be taken less than the relief valve opening pressure. The steamside of steam-driven pumps shall be hydraulically tested to 1.5 times the steam pressure. Hydrostatic testing of pump housings on submerged pumps will normally not be required. 3.4.3 Pump capacities shall be checked with the pump running at design condition (rated speed and pressure head, viscosity, etc.). Capacity test may be dispensed with for pumps produced in series when previous satisfactory tests have been carried out on similar pumps. 3

For centrifugal pumps having capacities less than 1 000 m /h, the pump characteristic (head-capacity curve) shall be determined for each type of pump. For centrifugal pumps having capacities equal to or greater than 3 1 000 m /h, the pump characteristic shall be determined over a suitable range on each side of the design point, for each pump. 3.4.4 Special survey arrangements for testing of pumps may be agreed upon.

4 Cargo heating 4.1 General 4.1.1 The heating media shall be compatible with the cargo and the temperature of the heating medium is normally not to exceed 220°C. 4.1.2 Supply and return pipes for heating coils fitted in cargo tanks, shall be arranged for blank flanging outside the engine or boiler room.

4.2 Steam heating 4.2.1 Water systems and steam systems shall comply with Pt.4 Ch.6 unless otherwise stated. 4.2.2 Condensate from cargo heating systems shall be led into an observation tank placed in an easily accessible, well ventilated and well illuminated position where it can easily be observed whether the condensate is free from oil or not. The scum pipes shall be led to a waste oil tank. If the condensate shall be used as feed water for boilers, an effective oil filtering system shall be arranged.

4.3 Thermal oil heating 4.3.1 Requirements to thermal-oil installations are given in Pt.4 Ch.7 Sec.3 [3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 43

Part 5 Chapter 5 Section 4

3.4 Testing

— system is so arranged that a positive pressure in the heating coil within a cargo tank shall be at least 3 m water column above the static head of the cargo when circulating pump is not in operation — the thermal oil system expansion tank shall be fitted with high and low level alarms — means shall be provided in the thermal oil system expansion tank for detection of flammable cargo vapours — valves for the individual heating coils shall be provided with locking arrangement to ensure that the coils are under static pressure at all times.

4.4 Heating of cargo with temperatures above 120°C 4.4.1 Heating plants for asphalt tanks shall be arranged with redundancy. Redundancy is required for boilers/ thermal oil heaters, heat exchangers and as well as active components (e.g. circulation pumps). Failure of a redundant component is not to reduce the installed heating capacity by more than 50%. 4.4.2 Heating coils in asphalt tanks shall be separated into at least two independent systems. Emergency cross connections may however be accepted. 4.4.3 Cargo pumps, P/V-valves (if fitted), automatic vent heads (if fitted) and cargo lines shall be provided with arrangements for heating. 4.4.4 Temperature gauges shall be arranged in each cargo tanks enabling the recording of temperatures at bottom, midway between bottom and deck and at deck level in order to prevent overheating of cargo. 4.4.5 Heating coils shall be tested according to the non-destructive testing requirements listed in Pt.4 Ch.6 Sec.9 [1.5].

5 Bow and stern loading and unloading arrangements 5.1 General Subject to the approval of the society, cargo piping may be fitted to permit bow and stern loading and unloading.

5.2 Piping arrangement 5.2.1 In addition to Pt.4 Ch.6 Sec.8, the following provisions apply: a) b)

c) d) e)

Bow and stern loading and unloading pipes shall be led outside accommodation spaces, service and machinery spaces within the accommodation or control stations. Cargo, stripping and vapour return piping (if fitted) forward or aft of the cargo area, except at the loading shore connection valve, shall have welded connections only. Such piping shall be clearly identified and fitted with two valves or one valve and a spool piece or blanks at its connection to the cargo piping system within the cargo area. The shore connection shall be fitted with a shut-off valve and a blank flange. Spray shields shall be provided at the connections specified in c). Arrangements shall be provided for complete drainage of the stern loading pipe back to the to the cargo area, preferably into a cargo tank. This may be achieved by arranging the pipe as self-draining or providing connections for line-blowing. For piping that is not self-draining, the ability to obtain complete draining is subject to testing.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 44

Part 5 Chapter 5 Section 4

4.3.2 Heating of liquid cargoes with flash point not exceeding 60°C shall be arranged by means of a separate secondary system located in the cargo area. However, a single circuit system may be accepted on the following conditions:

g) h) i) j)

Arrangements shall be made to allow for inert gas purging and gasfreeing of the piping to the cargo area. Entrances, air inlets and openings to accommodation spaces shall comply with SOLAS Reg. II-2/4.5.1.6 to 4.5.2.3. See also IMO MSC/Circ.474/Corr.1. Openings and access doors to mentioned spaces shall not face the cargo shore connection. A fixed foam fire-extinguishing system covering loading and unloading areas shall be provided. Loading and unloading arrangements shall not interfere with safety equipment. Continuous coamings or drip trays with a coaming height of at least 300 mm shall be fitted to keep any spills away from accommodation and service areas.

Regarding additional class notations Bow loading or STL for offshore loading operations, see Pt.6 Ch.4 Sec.1. Guidance note: In e) partial elevation of the stern loading pipe should be avoided as it impairs the ability to drain the pipe back to the cargo area. In g) an opening which does not have a direct line of sight to the shore connection and is located outside the hazardous zone in way of the shore connection is not considered to face the cargo area. Any opening located more than 10 m from the cargo shore connection may be accepted not facing the cargo shore connection on the condition that it is maintained closed during cargo handling operations. Note that ventilation openings to spaces containing machinery in use during cargo handling operations, as well as emergency generator rooms, are not considered capable of being maintained closed. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 45

Part 5 Chapter 5 Section 4

f)

1 Gas-freeing of cargo tanks 1.1 General 1.1.1 Means for gas-freeing of the cargo tanks shall be provided. The gas-freeing system shall be used exclusively for ventilating and gas-freeing purposes. The system may, however, be combined with an inert gas system. 1.1.2 There shall be no connection between the gas-freeing system and the ventilation system for cargo pump room. 1.1.3 Permanently installed ventilating and gas-freeing systems with non-permanent connections to cargo tanks or cargo piping, shall comply with the following: — Where the fans are located in a non-hazardous space, the air supply piping from the fan shall have an automatically operated shut-off valve and a non-return valve in series. — The valves shall be located at the bulkhead where the air supply piping leaves the non-hazardous space, with at least the non-return valve on the outside. — The shut-off valve shall open after the fans are started, and close automatically when the fans stop. — Fans shall be of non-sparking type and certified in accordance with Sec.6 [1.2]. 1.1.4 If a connection is fitted between the inert gas supply mains and the cargo piping system, arrangements shall be made to ensure an effective isolation having regard to the large pressure difference which may exist between the systems. This isolation may consist of two shut-off valves with an arrangement to vent the space between the valves. The valve on the cargo side of the separation shall be of non-return type with a positive means of closure. Alternatively, two shut-off valves with a removable spool piece may be accepted. See Figure 1. (IACS UI SC62 (1985)) CARGO PIPING NON RETURN VALVE SPOOL PIECE VENTING

INERT GAS MAIN

Figure 1 Example of effective isolation 1.1.5 For ships required to be inerted when carrying flammable oil, before gas-freeing with air, the cargo tanks shall be purged with inert gas. When the ship is provided with an inert gas system, gas outlets for tank purging and gasfreeing purposes shall comply with [2], and be positioned as far as practicable from the inert gas and air inlets. Alternatively, gas outlets may be arranged specifically for this purpose. Such outlets shall have a minimum height of 2 m above tank deck and dimensioned to give a minimum vertical exit velocity of 20 m/s, when any three cargo tanks are simultaneously supplied with inert gas, until the concentration of hydrocarbon vapours in the cargo tanks has been reduced to less than 2% by volume. Thereafter, gasfreeing may take place at the cargo tank deck level.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 46

Part 5 Chapter 5 Section 5

SECTION 5 GAS-FREEING AND VENTING OF CARGO TANKS

1.2 Gas-freeing of cargo tanks for barges Gas-freeing equipment is not required to be installed nor stored onboard. The tank hatches shall be arranged so as to facilitate the use of portable gas-freeing equipment.

2 Cargo tank venting systems 2.1 General 2.1.1 All cargo tanks intended for the carriage of cargoes with a flashpoint not exceeding 60°C, shall be provided with system(s) for over- and underpressure relief as follows: 1)

2)

A breathing system for preventing excessive overpressure and vacuum created due to temperature variations and generation of cargo vapour when tanks are not being connected to or have been isolated from a venting system as specified in 2). Such breathing shall be through P/V-valves, (pressure or vacuum relief valves). A venting system for preventing excessive overpressure or vacuum when tanks are being loaded or unloaded with closed tank hatch covers.

The breathing and venting systems may be independent or combined and may be connected to an inert gas system. 2.1.2 The system(s) shall be designed with a secondary mean for preventing excessive overpressure and vacuum in the event the primary mean of venting is isolated or fails. The following arrangements are acceptable: 1) 2)

For ships where cargo tanks are connected to a common venting system with a gas outlet with capacity as required by [2.2.13], the P/V-valves as required by [2.1.1].(1) are accepted as the secondary means of venting, with a capacity as required by [2.2.14]. For ships where cargo tanks are not connected to a common venting system with a common gas outlet with capacity as required by [2.2.13], one of the following arrangements can be accepted: — Two P/V-valves fitted to each individual cargo tank, without means for isolation, each with a capacity as required by [2.2.14]. — Pressure sensors fitted in each individual cargo tank, and connected to an alarm system may be accepted. The setting of the over-pressure alarm shall be above the pressure setting of the P/V-valve and the setting of the under-pressure alarm shall be below the vacuum setting of the P/V-valve. The alarm settings shall be within the design pressures of the cargo tanks. The settings shall be fixed and not arranged for blocking or adjustment in operation, unless the ship is approved for carrying P/Vvalves with different settings. — In case the pressure sensors required are also used for USCG vapour return purposes, then the system shall be provided with two fixed settings. For ships where inerting is not mandatory, the system shall be provided with mode selection so that the vapour return alarms are blocked except when the ship is loading with vapour return. See Sec.9 regarding high level alarms, overflow systems etc.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 47

Part 5 Chapter 5 Section 5

1.1.6 When the ship is not provided with an inert gas system the operation shall be such that the flammable vapour is discharged initially through the vent outlets as specified in [2], or through outlets at least 2 m above the tank deck level with a vertical efflux velocity of at least 30 m/s maintained during the gasfreeing operation, or through outlets at least 2 m above the tank deck level with a vertical efflux velocity of at least 20 m/s and which are protected by flame arresting elements as specified in [2.2.12]. When the flammable vapour concentration at the outlet has been reduced to 30% of LEL, gasfreeing may be continued at tank deck level.

For ships with tanks connected to a common venting system, the common gas outlet is considered as the primary mean of cargo tank venting during loading (and unloading for ships not required to be provided with inert gas systems when carrying oil). For ships without or having tanks not always connected to a common venting system, the full flow P/V-valves required fitted to each tank are considered to be the primary mean of venting during loading (and unloading for ships not required to be provided with inert gas systems when carrying oil). Inert gas supply is considered to be the primary mean of venting during unloading for ships required to be provided with inert gas systems when carrying oil. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2 System design 2.2.1 Pipes for breathing and venting shall be led from each tank’s highest point and shall be self-draining to the cargo tanks under all normal conditions of trim and list. 2.2.2 A separate system (e.g. stand pipe) for each tank or connection of tanks to a common cargo tank venting main pipe may be approved. When connection to a common main pipe is arranged, each branch pipe shall be provided with isolation valves. The isolation valves should preferably to fitted between the cargo tank and any spool piece or spectacle flange if fitted. Any stop valves fitted shall be provided with locking arrangements. There shall be a clear visual indication of the operational status of the valves or other acceptable means. 2.2.3 If the tank is not fitted with a separate P/V valve, the means of isolation shall be constructed in such a way that tank breathing is maintained when the branch pipe is isolated. 2.2.4 Shut-off valves shall not be fitted either above or below P/V valves, but by-pass valves may be provided. 2.2.5 The opening pressure of the P/V-valves pressure relief valves shall be less than the design vapour pressure for the cargo tanks. It shall also be less than the opening pressure of any P/V-breaker fitted, also taking into account pressure drop in the venting pipe between cargo tank and the P/V-valve. The opening pressure of the vacuum relief valves shall normally not be lower than 0.07 bar below atmospheric pressure and shall not be lower than the vacuum relief opening pressure of any P/V-breaker. Guidance note: For ships provided with an in-line P/V-breather valve between the common cargo tank venting/inert gas main line and the mast riser outlet for the purpose of tank pressure control, the opening pressures should be such that the in-line P/V-breather valve opens before the P/V-valves fitted to each cargo tank. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.6 P/V valves shall be located on open deck and shall be of a type which allows the functioning of the valve to be easily checked. A permanent access arrangement shall be provided to enable such checking. 2.2.7 For venting systems for high temperature cargoes see Sec.4 [4.4.3]. 2.2.8 Intake openings of vacuum relief valves shall be located at least 1.5 m above tank deck, and shall be protected against the sea. The arrangement shall comply with the requirements in Pt.3 Ch.12. 2.2.9 When the venting system during loading and unloading is by free flow of vapour mixtures, the outlets shall be not less than 6 m above the tank deck or gangway, if situated within 4 m of the gangway, and located not less than 10 m measured horizontally from air intakes and openings to enclosed spaces containing a source of ignition, and from equipment which may constitute an ignition hazard. 2.2.10 When the venting system during loading and unloading is by high velocity discharge the height of the gas outlets shall be located at a minimum height of 2 m above tank deck or gangway, if situated within

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 48

Part 5 Chapter 5 Section 5

Guidance note:

2.2.11 Gas outlets used during loading shall be directed vertically upwards and without obstructions. 2.2.12 Gas outlets and air inlets for cargo tanks shall have flame arresting elements tested and approved according to IMO MSC/Circ.677 as amended by MSC/Circ.1009. 2.2.13 The flow area of the venting system used during loading shall be based upon not less than 125% of the gas volume flow corresponding to the maximum design loading rate. Any P/V-valve fitted to a cargo tank as required by [2.1.1] shall have a capacity for the relief of full flow overpressure of not less than 125% of the gas volume flow corresponding to the maximum design loading rate for each tank. Similarly the P/V-valve capacity for the relief of underpressure shall be not less than the gas flow corresponding to the maximum design discharge rate for each tank. Note: The requirement to P/V-valve capacity applies to any P/V-valve which is required for the relief of over- and underpressure in case a cargo tank is isolated from a common cargo tank venting system (e.g. closed isolation valve) or gas outlet (e.g. mast riser valve closed). USCG vapour emission control systems (VECS): Note that for ship intended to comply with USCG regulations, the maximum allowable liquid loading rate when loading with vapour return will be determined by the capacity of the P/V-valves fitted to each tank. Under USCG regulations the P/V-valve capacity 3

shall take into account the vapour growth rate (min. 1.25) and the air vapour density (min. recommended 3.0 kg/m ) of the cargo to be carried. For ships provided with e.g. an in-line P/V-breather valve between the common cargo tank venting/Inert gas main line and the mast riser outlet, the opening pressure of this P/V-breather valve should be taken into account in the pressure drop calculations required by the USCG. However, if it is possible to isolate the P/V-breather valve during vapour return and procedures for same is included in the VECS operation manual, the opening pressure may be disregarded. ---e-n-d---o-f---n-o-t-e---

2.2.14 In systems where in-line P/V valves are installed, means for draining shall be fitted where condensate may accumulate.

2.3 Venting of cargo tanks for barges 2.3.1 The cargo tanks shall be provided with a venting system to facilitate loading and unloading with closed tank hatches without imposing excessive overpressure or vacuum on the tanks. 2.3.2 Breathing system with P/V valves will normally not be required.

2.4 Volatile organic compounds (VOC) Crude oil tankers (tanker for oil) shall be provided with an approved volatile organic compound (VOC) management plan in accordance with MARPOL Annex VI, Reg. 15.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 49

Part 5 Chapter 5 Section 5

4 m of the gangway, and located not less than 10 m measured horizontally from air intakes and openings to enclosed spaces containing a source of ignition, and from equipment which may constitute an ignition hazard. High velocity devices shall be of an approved type.

1 Ventilation systems 1.1 General 1.1.1 Any ducting used for the ventilation of hazardous spaces shall be separate from that used for the ventilation of non-hazardous spaces. Ventilation systems within the cargo area shall be independent of other ventilation systems. 1.1.2 Air inlets for hazardous enclosed spaces shall be taken from areas which, in the absence of the considered inlet, would be non-hazardous. Air inlets for non-hazardous enclosed spaces shall be taken from non-hazardous areas at least 1.5 m from the boundaries of any hazardous area. Where the inlet duct passes through a more hazardous space, the duct shall have over-pressure relative to this space, unless mechanical integrity and gas-tightness of the duct will ensure that gases will not leak into it. 1.1.3 Air outlets from non-hazardous spaces shall be located outside hazardous areas. 1.1.4 Air outlets from hazardous enclosed spaces shall be located in an open area which, in the absence of the considered outlet, would be of the same or lesser hazard than the ventilated space. 1.1.5 Ventilation ducts for spaces within the cargo area shall not be led through non-hazardous spaces. 1.1.6 Non-hazardous enclosed spaces shall be arranged with ventilation of the overpressure type. Hazardous spaces shall have ventilation with under-pressure relative to the adjacent less hazardous spaces. 1.1.7 Starters for fans for ventilation of gas-safe spaces within the cargo area shall be located outside this area or on open deck. If electric motors are installed in such spaces, the ventilation capacity shall be large enough to prevent the temperature limits specified in Pt.4 Ch.8 from being exceeded, taking into account the heat generated by the electric motors. 1.1.8 Wire mesh protection screens of not more than 13 mm square mesh shall be fitted in outside openings of ventilation ducts. For ducts where fans are installed, protection screens shall also be fitted inside of the fan to prevent the entrance of objects into the fan housing. 1.1.9 Spare parts for fans shall be carried onboard. Normally wear parts for one motor and one impeller is required for each type of fan serving spaces in the cargo area. 1.1.10 Ventilation inlets and outlets for spaces in the cargo area that are required to be continuously mechanically ventilated at sea, shall be located so that they are operable in all weather conditions. This implies that they shall be arranged at a height above deck as required in Pt.3 Ch.12 Sec.7 [4] as a ventilator not requiring closing appliances.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 50

Part 5 Chapter 5 Section 6

SECTION 6 VENTILATION SYSTEMS WITHIN THE CARGO AREA OUTSIDE THE CARGO TANKS

Spaces such as cargo pumprooms, ballast pumprooms and ballast water treatment spaces do normally not require continuous mechanical ventilation at sea. Spaces such as nitrogen rooms, cargo heater rooms and deck trunks containing cargo piping and cargo heaters may however require continuous ventilation at sea. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Fans serving hazardous spaces 1.2.1 Fans shall be certified as required by Sec.1 Table 7. Associated electric motors and motor starters shall be certified as required by Pt.4 Ch.8 Sec.1 Table 3. Guidance note: It is recommended that fans are certified in accordance with EN13463-1, EN13463-5 and EN14986. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.2 Electric fan motors shall not be installed in ventilation ducts for hazardous spaces unless the motor is certified for the same hazard zone as the space served. 1.2.3 Fans shall be designed with the least possible risk for spark generation. 1.2.4 Minimum safety clearances between the casing and rotating parts shall be such as to prevent any friction with each other. The radial air gap between the impeller and the casing shall not be less than 0.1 mm of the diameter of the impeller shaft in way of the bearing, but not less than 2 mm. It may be less than 13 mm. 1.2.5 The parts of the rotating body and of the casing shall be made of materials which are recognised as being spark proof, and they shall have antistatic properties. Furthermore, the installation on board of the ventilation units shall be such as to ensure the safe bonding to the hull of the units themselves. Resistance between any point on the surface of the unit and the hull, shall 6 not be greater than 10 Ohm. The following combinations of materials and clearances used in way of the impeller and duct are considered to be non-sparking: — impellers and/or housing of non-metallic material, due regard being paid to the elimination of static electricity — impellers and housings of non-ferrous metals — impellers of aluminium alloys or magnesium alloys and a ferrous (including austenitic stainless steel) housing on which a ring of suitable thickness of non- ferrous materials is fitted in way of the impeller, due regard being paid to static electricity, reliability of the arrangement for securing of the ring to the housing and corrosion between ring and housing — impellers and housing of austenitic stainless steel — any combination of ferrous (including austenitic stainless steel) impellers and housing with not less than 13 mm tip design clearance. 1.2.6 Any combination of an aluminium or magnesium alloy fixed or rotating component, and a ferrous fixed or rotating component, regardless of tip clearance, is considered a spark hazard and shall not be used in these places.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 51

Part 5 Chapter 5 Section 6

Guidance note:

2.1 General 2.1.1 The required capacity of the ventilation plant is normally based on the total volume of the room. An increase in required ventilation capacity may be necessary for rooms with a complicated shape. 2.1.2 Failure of required fixed mechanical ventilation shall be alarmed (audible and visual) at a manned station.

2.2 Non-hazardous spaces 2.2.1 Non-hazardous spaces with opening to a hazardous area, shall be arranged with an air-lock in accordance with Sec.3 [4.1.5] and Sec.3 [4.1.6]. — Non-hazardous spaces with openings into hazardous zone 1 shall be arranged as a pressurized space, protected by an air-lock. — The air lock shall be provided with a mechanical ventilation system independent of that of the space protected by the air-lock. — The air lock shall be maintained at an overpressure relative to the hazardous area it opens into. — Electrical equipment that is located in spaces protected by airlocks that are not of the certified safe type, shall be de-energized in case of loss of overpressure in the pressurized space. Guidance note: Requirements applicable for air-lock arrangement are given in IEC 60092-502 [4]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.2 Machinery necessary for maintaining main functions, as well as safety systems such as the emergency generator and emergency fire pumps, shall not be located in spaces where automatic disconnection of electrical equipment is required. Guidance note: Equipment suitable for operating in a zone 1, is not required to be disconnected. Certified flameproof lighting, may have a separate disconnection circuit, satisfying [2.3.2]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3 Cargo handling spaces 2.3.1 A permanent mechanical ventilation system of the extraction type shall be installed, capable of circulating sufficient air to give at least 20 air changes per hour. In the cargo pump room, exhaust trunking shall be arranged as follows: — in the cargo pump room bilges just above the transverse floor plates or bottom longitudinals, so that air can flow over the top from adjacent spaces — an emergency intake located 2 m above the pump room lower grating. This emergency intake would be used when the lower intakes are sealed off due to flooding in the bilges. The emergency intake shall have a damper fitted, which can be remotely opened from the exposed main deck in addition to local opening and closing arrangement at the lower grating. 2.3.2 The electrical lighting in the cargo pump room shall be fitted with an interlock so arranged that the ventilation shall be in operation before the electrical supply to the lighting in the room gets connected.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 52

Part 5 Chapter 5 Section 6

2 Ventilation arrangement and capacity requirements

2.3.3 The exhaust outlets, which shall discharge upwards, shall be situated at least 3 m above tank deck.

2.4 Other hazardous spaces normally entered 2.4.1 Pipe tunnel, ballast pump room (when not located adjacent to cargo tanks) and other similar spaces below deck, not covered by [2.3], where access may be necessary for normal operation and maintenance, shall be equipped with a fixed separate ventilation system, with a capacity of at least 8 air changes per hour. Ballast pumprooms adjacent to cargo tanks and located below deck shall be equipped with a fixed separate ventilation system, with capacity of at least 20 air changes per hour. 2.4.2 Other spaces situated on or above cargo deck level (e.g. cargo handling gear lockers and cargo sample lockers) may be accepted with natural ventilation only.

2.5 Spaces not normally entered 2.5.1 Spaces not normally entered, as defined in Sec.1 [3.1], shall be arranged for gasfreeing. Where necessary, owing to the arrangement of the spaces, necessary ducting shall be permanently installed in order to ensure safe and efficient gasfreeing. 2.5.2 A mechanical ventilation system (permanent or portable) shall be provided, capable of circulating sufficient air to the compartments concerned. Where a permanent ventilation system is not provided, approved means of portable mechanical ventilation shall be provided. For permanent installations the capacity of 8 air changes per hour shall be provided and for portable systems the capacity of 16 air changes per hour. Fans or blowers shall be clear of personnel access openings, and shall comply with [1.2.5]. 2.5.3 Double hull and double bottom spaces shall be fitted with suitable connections for the supply of air for gas freeing.

2.6 Ventilation systems for barges 2.6.1 Engine room and cargo pump room situated below deck shall have separate mechanical ventilation systems of overpressure type and underpressure type, respectively. 2.6.2 Engine room, cargo pump room and service spaces situated on deck may have natural ventilation systems. 2.6.3 Accommodation spaces shall be provided with mechanical ventilation of the overpressure type.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 53

Part 5 Chapter 5 Section 6

Emergency lighting shall not be interlocked. Failure of the ventilation system shall not cause the lighting to go out.

1 Fire safety measures for tankers 1.1 Application 1.1.1 It is the responsibility of the government of the flag state to ensure that ships are provided with the fire safety measures required by the International Convention for the Safety of Life at Sea, 1974, as amended (hereafter referred as SOLAS). 1.1.2 Where the government of the flag state is authorizing the Society to issue the SOLAS Cargo Ship Safety Construction and Cargo Ship Safety Equipment certificates on its behalf, the Society will apply the SOLAS fire protection, detection and extinction requirements as applicable for tankers and as referred to in Pt.4 Ch.10. 1.1.3 If the government of the flag state is not authorizing the Society to take care of the fire safety measures in SOLAS related to tankers, the SOLAS Cargo Ship Safety Construction and Cargo Ship Safety Equipment certificates from the flag state will be used as basis for this notation.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 54

Part 5 Chapter 5 Section 7

SECTION 7 FIRE PROTECTION AND EXTINCTION

1 General 1.1 Application 1.1.1 The requirements in this section are additional to those given in Pt.4 Ch.8 and apply to tankers intended for the carriage of oil cargoes in bulk having a flash point not exceeding 60°C (closed cup test). 1.1.2 For combination carriers, the requirement for oil tankers generally apply. However, exemptions from the requirements for tankers may be accepted for equipment which is only used in dry cargo service, after consideration in each case. Instructions will be given that such equipment shall be disconnected and earthed when the ship is used as tanker and until it has been gas-freed after such service. 1.1.3 Oil tankers exclusively built to carry cargoes with flash point above 60°C, will be specially considered in each case. See [3.3].

1.2 Insulation monitoring Insulation fault; Device(s) to continuously monitoring the insulation earth shall be installed for both insulated and earthed distribution systems. An audible and visual alarm shall be given at a manned position in the event of an abnormally low level of insulation resistance and or high level of leakage current.

2 Electrical installations in hazardous areas 2.1 General 2.1.1 Electrical equipment and wiring shall in general not be installed in hazardous areas. Where essential for operational purposes, arrangement of electrical installations in hazardous areas shall comply with Pt.4 Ch.8 Sec.11, based on area classification as specified in [3]. In addition, installations as specified in [2.1.2] are accepted. Except as specified in [1.1.2] and [3.3], operational procedures are not acceptable as an equivalent method of ensuring compliance with these rules. Electrical equipment installed in hazardous areas shall as a minimum comply with the requirements to gas group IIA and temperature class T3. 2.1.2 In zone 1. Impressed cathodic protection equipment, electric depth-sounding devices and log devices are accepted provided the following is complied with: — Such equipment shall be of gas-tight construction or be housed in a gas tight enclosure. — Cables shall be installed in steel pipes with gas-tight joints up to the upper deck. — Corrosion resistant pipes, providing adequate mechanical protection, shall be used in compartments which may be filled with seawater (e.g. permanent ballast tanks). — Wall thickness of the pipes shall be as for overflow and sounding pipes through ballast or fuel tanks, in accordance with Pt.4 Ch.6 Sec.8.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 55

Part 5 Chapter 5 Section 8

SECTION 8 AREA CLASSIFICATION AND ELECTRICAL INSTALLATIONS

3.1 General 3.1.1 Area classification is a method of analyzing and classifying the areas where explosive gas atmospheres may occur. The object of the classification shall allow the selection of electrical apparatus able to be operated safely in these areas. 3.1.2 In order to facilitate the selection of appropriate electrical apparatus an the design of suitable electrical installations, hazardous areas are divided into zones 0, 1 and 2 according to the principles of the standards IEC 60079-10 and IEC 60092-502. Classification of areas and spaces typical for tankers, is given in [3.2] and [3.3], based on IEC 60092-502. 3.1.3 Areas and spaces other than those classified in [3.2] and [3.3], shall be subject to special consideration. The principles of the IEC standards shall be applied. 3.1.4 A space with opening to an adjacent hazardous area on open deck, may be made into a less hazardous or non-hazardous space, by means of overpressure. Requirements to such pressurisation are given in Sec.6 [2]. 3.1.5 Ventilation ducts shall have the same area classification as the ventilated space. 3.1.6 With the exception of spaces arranged in accordance with Sec.6 [2.2.1], any space having an opening into a hazardous area or space, having a more severe hazardous zone classification, will be considered to have the same hazardous zone classification as the zone it has an opening into. Guidance note: Openings are considered to be any access door, ventilation inlets or outlets or other boundary openings. Bolted plates that are normally closed and only opened when area has been confirmed gas free may be accepted. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2 Tankers for carriage of products with flashpoint not exceeding 60°C 3.2.1 Hazardous areas zone 0 The interiors of cargo tanks, slop tanks, any pipework of pressure-relief or other venting systems for cargo and slop tanks, pipes and equipment containing the cargo or developing flammable gases or vapours. 3.2.2 Hazardous area zone 1 1) 2) 3) 4) 5) 6) 7)

Void spaces and cofferdams adjacent to, above and below integral cargo tanks. Hold spaces containing independent cargo tanks. Ballast tanks and any other tanks adjacent to cargo tanks. Cargo handling spaces (including cargo pump rooms). Enclosed or semi-enclosed spaces, immediately above cargo tanks (for example, between decks) or having bulkheads above and in line with cargo tanks bulkheads, unless protected by a diagonal plate acceptable to the appropriate authority. Spaces, other than cofferdam, adjacent to and below the top of a cargo tanks (for example, trunks, passageways, ballast pumprooms, ballast treatment spaces and hold spaces). Areas on open deck, or semi- enclosed spaces on deck, within 3 m of any cargo tanks outlet, gas or vapour outlet (see note), cargo manifold valve, cargo valve, cargo pipe flange, cargo pump-room ventilation outlets and cargo tank openings for pressure release provided to permit the flow of small volumes of gas or vapour mixtures caused by thermal variation.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 56

Part 5 Chapter 5 Section 8

3 Area classification

Such areas are, for example, all areas within 3 m of cargo tank hatches, sight ports, tank cleaning openings, ullage openings, sounding pipes, cargo vapour outlets. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

8)

9) 10) 11) 12) 13)

Areas on open deck, or semi-enclosed spaces on open deck above and in the vicinity of any cargo gas outlet designed for the passage of large volumes of gas or vapour mixture during cargo loading and ballasting or during discharging, within a vertical cylinder of unlimited height and 6 m radius centred upon the centre of the outlet, and within a hemisphere of 6 m radius below the outlet. Areas on open deck, or semi-enclosed spaces on deck, within 1.5 m of cargo pump room entrances, cargo pump room ventilation inlets, openings into cofferdams or other zone 1 spaces. Areas on the open deck within spillage coamings surrounding cargo manifold valves and 3 m beyond these, up to a height of 2.4 m above the deck. Areas on open deck over all cargo tanks (including ballast tanks within the cargo tank area) where structures are restricting the natural ventilation and to the full breadth of the ship plus 3 m fore and aft of the forward-most and the aft-most cargo tank bulkhead, up to a height of 2.4 m above the deck. Compartments for cargo hoses and contaminated cargo equipment. Enclosed or semi-enclosed spaces in which pipes containing liquid cargoes or cargo vapour are located.

3.2.3 Hazardous areas zone 2 1) 2) 3) 4) 5)

6)

Areas within 1.5 m surrounding open or semi-enclosed spaces of zone 1 as specified in [3.2.2], if not otherwise specified in this standard. Spaces 4 m beyond the cylinder and 4 m beyond the sphere defined in [3.2.2] 8). The spaces forming an air-lock as defined in Sec.1 [3.1] and Sec.3 [4.1.5] and [4.1.6]. Areas on open deck extending to the coamings fitted to keep any spills on deck and away from the accommodation and service areas and 3 m beyond these up to a height of 2.4 m above deck. Areas on open deck over all cargo tanks (including all ballast tanks within the cargo tank area) where unrestricted natural ventilation is guaranteed and to the full breadth of the ship plus 3 m fore and aft of the forward-most and aft-most cargo tank bulkhead, up to a height of 2.4 m above the deck. For ships subject to [3.2.2] 11), the area within 1.5 metres of the area specified in [3.2.2] 11). spaces forward of the open deck areas to which reference is made in [3.2.2] 11) and 5), below the level of the main deck, and having an opening on to the main deck or at a level less than 0.5 m above the main deck, unless: a) b)

the entrances to such spaces do not face the cargo tank area and, together with all other openings to the spaces, including ventilating system inlets and exhausts, are situated at least 10 m horizontally from any cargo tank outlet or gas or vapour outlet, and the spaces are mechanically ventilated.

7)

Fore peak ballast tanks, if connected to a piping system serving ballast tanks within the cargo area. See Sec.4 [2.3].

8)

Ballast pumprooms or ballast treatment spaces which are not located adjacent to cargo tanks, but which could contain contaminated ballast water from ballast tanks located adjacent to cargo tanks.

Spaces containing ballast pumps or treatment systems only used for filling of ballast tanks and are provided with means for prevention of backflow are not considered hazardous. See, however, Pt.6 Ch.7 Sec.1 regarding ballast treatment systems generating explosive gases.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 57

Part 5 Chapter 5 Section 8

Guidance note:

3.3.1 Unheated cargoes and cargoes heated to a temperature below and not within 15°C of their flashpoint. Hazardous areas zone 2. The interiors of cargo tanks, slop tanks, any pipework of pressure-relief or other venting systems for cargo and slop tanks, pipes and equipment containing the cargo. 3.3.2 Cargoes heated above their flashpoint and cargoes heated to a temperature within 15°C of their flashpoint. The requirements of [3.2] are applicable. Guidance note: It is acceptable that an operational limitation is inserted in the appendix to class certificate specifying that the ship is approved on the condition that cargo is not heated to within 15°C of its flashpoint. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4 Inspection and testing 4.1 General 4.1.1 Before the electrical installations in hazardous areas are put into service or considered ready for use, they shall be inspected and tested. All equipment, cables, etc. shall be verified to have been installed in accordance with installations procedures and guidelines issued by the manufacturer of the equipment, cables, etc., and that the installations have been carried out in accordance to Pt.4 Ch.8 Sec.11. 4.1.2 For spaces protected by pressurisation it shall be examined and tested that the purging can be effected. Purge time at minimum flow rate shall be documented. Required shutdowns and or alarms upon ventilation overpressure falling below prescribed values shall be tested. For other spaces where area classification depends on mechanical ventilation it shall be tested that ventilation flow rate is sufficient, and that and required ventilation failure alarm operates correctly. 4.1.3 For equipment for which safety in hazardous areas depends upon correct operation of protective devices (for example overload protection relays) and or operation of an alarm (for example loss of pressurisation for an Ex(p) control panel) it shall be verified that the devices have correct settings and/or correct operation of alarms. 4.1.4 Where interlocking and shutdown arrangements are required (such as for submerged cargo pumps), they shall be tested. 4.1.5 Intrinsically safe circuits shall be verified to ensure that the equipment and wiring are correctly installed. 4.1.6 Verification of the physical installation shall be documented by yard. The documentation shall be available for the Society's surveyor at the site.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 58

Part 5 Chapter 5 Section 8

3.3 Tankers for carriage of products with flashpoint exceeding 60°C

5.1 General 5.1.1 The maintenance manual referred to in Sec.1 Table 5, shall be in accordance with the recommendations in IEC 60079-17 and 60092-502 and shall contain necessary information on: — Overview of classification of hazardous areas, with information about gas groups and temperature class. — Records sufficient to enable the certified safe equipment to be maintained in accordance with its type of protection (list and location of equipment, technical information, manufacturer's instructions, spares etc.). — Inspection routines with information about detailing level and time intervals between the inspections, acceptance/rejection criteria. — Register of inspections, with information about date of inspections and name(s) of person(s) who carried out the inspection and maintenance work. 5.1.2 Inspection and maintenance of installations shall be carried out only by experienced personnel whose training has included instruction on the various types of protection of apparatus and installation practices that shall be found on the vessel. Appropriate refresher training shall be given to such personnel on a regular basis.

6 Signboards 6.1 General 6.1.1 Where electric lighting is provided for spaces in hazardous areas, a signboard at least 300 mm shall be fitted at each entrance to such spaces with text: BEFORE A LIGHTING FITTING IS OPENED ITS SUPPLY CIRCUIT SHALL BE DISCONNECTED Alternatively a signboard with the same text can be fitted at each individual lighting fitting. 6.1.2 Where electric lighting is provided in spaces where the ventilation shall be in operation before the electric power is connected, a signboard at least 200 × 300 mm shall be fitted at each entrance, and with a smaller signboard at the switch for each lighting circuit, with text: BEFORE THE LIGHTING IS TURNED ON, THE VENTILATION SHALL BE IN OPERATION 6.1.3 Where socket-outlets are installed in cargo area or adjacent area, a signboard shall be fitted at each socket-outlet with text: PORTABLE ELECTRICAL EQUIPMENT SUPPLIED BY FLEXIBLE CABLES SHALL NOT BE USED IN AREAS WHERE THERE IS GAS DANGER Alternatively signboards of size approximately 600 mm × 400 mm, with letters of height approximately 30 mm, can be fitted at each end of the tank deck. 6.1.4 Where socket-outlets for welding apparatus are installed in areas adjacent cargo area, the socket outlet shall be provided with a signboard with text: WELDING APPARATUS SHALL NOT BE USED UNLESS THE WORKING SPACE AND ADJACENT SPACES ARE GAS-FREE.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 59

Part 5 Chapter 5 Section 8

5 Maintenance

1 General requirements For instrumentation and automation, including computer based control and monitoring, the requirements in this chapter are additional to those given in Pt.4 Ch.9. The control and monitoring systems shall be certified according to Sec.1 Table 7.

2 Cargo valves and pumps- control and monitoring 2.1 General 2.1.1 If valves and pumps for loading and unloading the ship are remotely controlled, all controls, indicators and alarms associated with a given cargo tank shall be centralised in one control station. Pump discharge pressure and vacuum meter shall be fitted in the control station. 2.1.2 Cargo pumps, ballast pumps and stripping pumps, installed in cargo pump rooms and driven by shafts passing through pump room bulkheads shall be fitted with temperature sensing devices for bulkhead shaft glands, bearings and pump casings. An alarm shall be initiated in the cargo control room or the pump control station. 2.1.3 Cargo pump rooms and hold spaces containing independent cargo tanks, shall be provided with bilge high level alarms. The alarm signals (visual and audible) shall be provided in the cargo control room or station. 2.1.4 Local operation of valves may be carried out from separate deck stands provided satisfactory position indication is arranged locally and at the control station mentioned in [2.1.1]. 2.1.5 Remote-controlled cargo tank valves shall be provided with an indication system, which at the manoeuvring stand indicates to the operator whether the valves are in open or closed position. A flow indicator in the hydraulic system for manoeuvring valves can be accepted. The flow indicator shall show whether the valves are in open or closed position. 2.1.6 Remote-controlled tank valves shall be arranged with means for manual (emergency) operation. A handpump which can be connected to the control system as near the valve as possible, will normally be accepted.

2.2 Computer based systems for cargo handling Local control of cargo handling systems independent of computer controlled systems will be required.

2.3 Centralised cargo control Ships having their cargo and ballast systems built and equipped, surveyed and tested in accordance with the requirements in Pt.6 Ch.4 Sec.2, may be given the additional class notation CCO.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 60

Part 5 Chapter 5 Section 9

SECTION 9 INSTRUMENTATION AND AUTOMATION

2.4.1 The operation of cargo and/or ballast systems may be necessary, under certain emergency circumstances or during the course of navigation, to enhance the safety of tankers. As such, measures shall be taken to prevent cargo and ballast pumps becoming inoperative simultaneously due to a single failure in the integrated cargo and ballast system, including its control and safety systems. 2.4.2 Integrated cargo and ballast systems meaning any integrated hydraulic and/or electric system used to drive both cargo and ballast pumps (including active control and safety systems and excluding passive components, e.g. piping), shall be designed and constructed as follows: 1) 2) 3) 4)

The emergency stop circuits of the cargo and ballast systems shall be independent from the circuits for the control systems. A single failure in the control system circuits or the emergency stop circuits are not to render the integrated cargo and ballast system inoperative. Manual emergency stops of the cargo pumps shall be arranged in a way that they are not to cause the stop of the power pack making ballast pumps inoperable. The control systems shall be provided with backup power supply, which may be satisfied by a duplicate power supply from the main switch board. The failure of any power supply shall provide audible and visible alarm activation at each location where the control panel is fitted. In the event of failure of the automatic or remote control systems, a secondary means of control shall be made available for the operation of the integrated cargo and ballast system. This shall be achieved by manual overriding and/or redundant arrangements within the control systems.

3 Cargo tank level monitoring 3.1 General 3.1.1 Types of level measuring devices: Open type: A method which makes use of an opening in the tank and directly exposes the operator to the cargo or its vapours. Examples of this type are ullage openings and gauge hatches. Restricted type: A device which penetrates the tank and which, when in use, permits a limited quantity of cargo vapour or liquid to be expelled to the atmosphere. When not in use, the device is completely closed. Examples of this type are rotary tube, fixed tube, slip tube and sounding pipe. Closed type: A device which penetrates the tank, but which is part of a closed system which keeps the cargo completely sealed off from the atmosphere. Examples of this type are sight glasses, pressure cells, float-tape systems, electronic or magnetic probe. 3.1.2 Each cargo tank shall be fitted with at least one level gauging device. Where only one liquid level measuring device is fitted it shall be arranged so that any necessary maintenance can be carried out while the cargo tank is in service. 3.1.3 If a closed measuring device is not mounted directly on the tank, it shall be provided with shut-off valves situated as close as possible to the tank. 3.1.4 Level measuring in ships with inerted tanks, see Sec.11 [3.5] For crude oil and petroleum products having a flashpoint not exceeding 60°C, closed type only is acceptable. For other cargo oils, open type or restricted type are acceptable.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 61

Part 5 Chapter 5 Section 9

2.4 Design of integrated cargo and ballast systems

Provision shall be made to guard against liquid rising in the venting system to a height which will exceed the design head of cargo tanks. This shall be accomplished by high level alarms or overflow control systems or other equivalent means, together with gauging devices and cargo tank filling procedures. High level alarms shall be independent of the closed level measuring system. Combined level measuring system and high level alarm systems may be accepted as equivalent to independent systems provided extensive self-monitoring is incorporated in the system covering all credible faults. Chemical carriers subject to the requirements of Ch.6 and provided with both high-level and overflow alarms, these are required to be independent of the closed level measuring system and of each other.

5 Oil and water interface detector The ship shall be provided with instruments for measuring the interface level between oil and water. The instrument(s) may be fixed or portable. Note: Oil and water interface detectors should be approved by an administration. ---e-n-d---o-f---n-o-t-e---

6 Gas detection in cargo pump room A system for continuous monitoring of the concentration of hydrocarbon gases shall be fitted. Sampling points or detector heads shall be located in suitable positions in order that potentially dangerous leakage is readily detected. When the hydrocarbon gas concentration reaches a pre-set level, which shall not be higher than 10% of the lower flammable limit, a continuous audible and visual alarm signal shall be automatically initiated in the pump-room, engine control room, cargo control room and navigation bridge, to alert personnel to the potential hazard. Sequential sampling is acceptable as long as it is dedicated for the pump room only, including exhaust ducts, and the sampling time is reasonably short. Guidance note: Suitable positions may be the exhaust ventilation duct and lower parts of the pump room above the floor plates. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7 Gas detection outside cargo pumprooms 7.1 Portable gas detection The ship shall be provided with approved portable gas detectors. Ships with inert gas systems shall be provided with two instruments for measuring O2-content, two instruments for measuring hydrocarbon-content in the range of 0 to 20% hydrocarbon gas by volume and two instruments for measuring low hydrocarbon gas-content 0 to 100% LEL. Ships without inert gas system shall be provided with two instruments for measuring O2-content and two instruments for measuring low hydrocarbon gas-content 0 to 100% LEL. Where the atmosphere in double hull spaces cannot be reliably measured using flexible gas sampling hoses, such spaces shall be fitted with permanent gas sampling lines. Alternatively a fixed gas detection system shall be fitted in these spaces. Alarms (visual and audible) shall be provided on the bridge and in the cargo control room. Ships for alternate carriage of oil and dry cargo, see Sec.10 [3.1.4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 62

Part 5 Chapter 5 Section 9

4 Cargo tank overflow protection

Gas detectors should be approved by an administration. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.2 Fixed gas detection 7.2.1 Oil tankers of 20 000 dwt and above, shall be provided with a fixed hydrocarbon gas detection system for measuring hydrocarbon gas concentrations in all ballast tanks and void spaces of double-hull and doublebottom spaces adjacent to the cargo or slop tanks, including the forepeak tank and any other tanks and spaces under the bulkhead deck adjacent to cargo tanks. The system shall comply with Reg.16 of the FSS code and MSC.1/Circ.1370 as well as the requirements in this section. 7.2.2 As the cargo pumproom gas detection system is required to be continuous, sequential type gas detection system serving a cargo pumproom shall be separated from that serving spaces adjacent to cargo tanks. 7.2.3 Any tank or compartment, except fuel tanks, located below the bulkhead deck and adjacent to a cargo or slop tank shall be provided with fixed gas detection. This includes e.g. cofferdams/voids, ballast pumprooms, freshwater tanks etc. (IACS UI SC268) 7.2.4 The term adjacent to the cargo tanks, also includes tanks and compartments located below the bullhead deck with a cruciform contact with the cargo or slop tanks, unless the structural configuration eliminates the possibility of leaks. (IACS UI SC268) 7.2.5 For cofferdams/void spaces and other dry compartments such as ballast pump rooms, one bottom sampling detector is acceptable. (IACS Rec. 123) 7.2.6 For ballast tanks and freshwater tanks top and bottom sampling points are always required unless the prohibition of partial filling is clearly stated in the trim and stability booklet/loading manual. (IACS Rec. 123) 7.2.7 The gas detection system shall be arranged with single sampling lines from each sampling point to the gas detection cabinet. Sampling lines from each sampling point in the same space may however be combined at deck level via a manually operated three-way valve arrangement or similar. The valve shall be provided with local indication of which sampling point is active (top or bottom). A signboard should be provided in CCR to specify procedure for manual operation of valves depending on operational mode as follows: — In loaded condition: valve shall be set so that lower sampling point is active. — In ballast/partial ballast condition: valve shall be set so that upper sampling point is active. (IACS Rec. 123) 7.2.8 Gas sampling pipes may penetrate a watertight subdivision provided the total cross sectional area of 2 such pipes do not exceed 710 mm between any two watertight compartments (i.e. a maximum single pipe diameter of 30 mm). The gas sampling pipes may however not be led through a cargo tank boundary. The penetrations shall be located as far as practical away from the ships shell. (IACS Rec. 123)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 63

Part 5 Chapter 5 Section 9

Guidance note:

Gas analysing units with non-explosion proof measuring equipment may be located in areas outside cargo areas, for example in the cargo control room, navigation bridge or engine room when mounted on the forward bulkhead provided the following requirements are observed: a) b) c) d)

e)

Sampling lines shall not run through gas non-hazardous spaces, except where permitted under e). The gas sampling pipes shall be equipped with flame arresters. Sample gas shall be led to the atmosphere with outlets arranged in a safe location. Bulkhead penetrations of sample pipes between non-hazardous and hazardous areas shall be of an approved type and have the same fire integrity as the division penetrated. A manual isolating valve shall be fitted in each of the sampling lines at the bulkhead on the gas safe side. The gas detection equipment including sample piping, sample pumps, solenoids, analysing units etc. shall be located in a reasonably gas tight (e.g. fully enclosed steel cabinet with a door with gaskets) which shall be monitored by its own sampling point. At gas concentration above 30% LFL inside the steel cabinet the entire gas analysing unit shall be automatically shut down. Where the cabinet cannot be arranged directly on the bulkhead, sample pipes shall be of steel or other equivalent material and without detachable connections, except for the connection points for isolating valves at the bulkhead and analysing units, and shall be routed on their shortest ways.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 64

Part 5 Chapter 5 Section 9

8 Installation requirements for analysing units

1 General The requirements in this section apply to ships intended to carry liquid oil cargoes in bulk with a flashpoint not exceeding 60°C or dry cargo, alternately. The requirements are supplementary to those for the class notation Tanker for oil or Tanker for oil products.

1.1 Class notation Ships satisfying the requirements in this section may be assigned one of the following class notations: Bulk carrier or tanker for oil (alternatively Tanker for oil products) Ore carrier or tanker for oil (alternatively Tanker for oil products)

1.2 Basic assumptions The rules in this section are based on the assumption that: — Dry cargo and liquid cargo with a flashpoint not exceeding 60°C are not carried simultaneously, except for cargo oil-contaminated water (slop) in the protected slop tank(s). — Before the ship enters dry cargo service, all cargo piping, tanks and compartments in the cargo area shall be cleaned and ventilated to the extent that the content of hydrocarbon gases is brought well below the lower explosion limit. Further, the cleaning shall ensure that the concentration of hydrocarbon gases remains below the lower explosion limit during the forthcoming dry cargo voyage. — Measurements of hydrocarbon gas content are carried out regularly during dry cargo service. Guidance note: Measurement of hydrocarbon gas content once every day is considered appropriate during the first two weeks. Later on this may be reduced, depending on the results of the previous measurements. When sailing into higher air or sea-water temperatures, measurements should be taken daily. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2 Cargo area arrangement and systems The ship shall comply with the requirements of Sec.12 for protected slop tank.

2.1 Design of cargo oil tanks 2.1.1 Cargo tanks shall be designed to facilitate efficient cleaning. The bottom, side and end boundaries of the tanks may be of the following alternative designs: — plane surfaces — corrugated surfaces — vertical stiffeners, but no internal primary structural members in the tanks. 2.1.2 In tanks where primary structural members are unavoidable, particular attention shall be paid to the arrangement and outfitting of cleaning facilities. The efficiency of such equipment shall be verified by a test after the discharge of the ship's first oil cargo. The established cleanliness and gas-free condition shall be verified by a measuring program approved by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 65

Part 5 Chapter 5 Section 10

SECTION 10 SHIPS FOR ALTERNATE CARRIAGE OF OIL CARGO AND DRY CARGO

2.2.1 Compartments in the cargo area such as pipe tunnels, stool tanks, cofferdams, etc. shall be arranged so as to avoid the spreading of hydrocarbons. For instance, stool tanks and cofferdams shall not have permanent openings to pipe tunnels. 2.2.2 The double bottom shall be arranged for segregated ballast with tanks of length not exceeding 0.2 L. 2.2.3 Pipe tunnels and other compartments of comparable extent in the cargo area shall be provided with access openings at forward and aft end. The access entrances shall be arranged from open deck or a cargo pump room, and shall be suitable for use for cleaning and gas-freeing operations. 2.2.4 Stool tanks and spaces containing cargo pumps and pipes shall be provided with access from open deck. The access openings shall be suitable for use for cleaning and gas-freeing operations. Access to such spaces from pipe tunnel may be accepted if the following items are complied with: — bolted manhole cover or equivalent gastight closing with oil-resistant packings and signboards with instruction to normally keep it closed. The cover shall be lifted 300 mm above bottom of stool tank to prevent back-flow of oil when opened. — ventilation pipes of sufficient size on port and starboard side for cross ventilation and gas-freeing by portable fans. 2.2.5 Access entrances and passages shall have a clear opening in accordance with Sec.3 [4.2]. 2.2.6 Openings which may be used for cargo operations are not permitted in bulkheads and decks separating oil cargo spaces from other spaces not designed and equipped for the carriage of oil cargoes unless alternative approved means are provided to ensure equivalent integrity.

2.3 Bilge, drainage and cargo piping 2.3.1 As far as compatible with the general arrangement of the ship, the cargo oil piping shall be located on open deck or within the cargo tanks. 2.3.2 If piping locations stated in [2.3.1] are not appropriate, the cargo oil piping may be located within special pipe tunnels of limited size. 2.3.3 The cargo oil piping system shall be designed and equipped so as to minimise the risk of oil leakage due to corrosion or to failures in the pipe connection fittings. Steel pipes inside water ballast tanks shall have a wall thickness not less than 12.5 mm. 2.3.4 A separate bilge system shall be provided for the compartments intended for carrying dry cargo. A separate cargo oil stripping system may be used for bilge pumping, provided the system has no connection to, or is easily isolated from, tanks not intended for dry cargo. 2.3.5 Bilge suctions in cargo holds, see Pt.4 Ch.6 Sec.4 [4]. 2.3.6 The bilge suctions of separate bilge system in cargo holds shall be arranged for blank flanging when the ship is carrying oil. 2.3.7 The cargo oil suctions in the holds intended for dry cargo shall be arranged for blank flanging when the ship is carrying dry cargo.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 66

Part 5 Chapter 5 Section 10

2.2 Arrangement and access to compartments

2.3.9 Arrangements shall be made to avoid damage to oil wells and blank-flanging arrangements due to dry cargo, grab discharging, etc. 2.3.10 Top wing tanks may be arranged with gravity overboard discharge, see Pt.3 Ch.12. 2.3.11 Dry compartments adjacent to cargo tanks shall be provided with bilge or drainage arrangement. Pipe tunnels shall be provided with bilge suctions at forward and aft ends. Bulkhead stool tanks shall be provided with bilge suctions.

2.4 Cleaning and gas-freeing 2.4.1 The cargo tanks shall be equipped with fixed or portable means for cleaning and gas-freeing. 2.4.2 The water cleaning system for cargo tanks with internal primary structural members shall comprise possibility for heating the cleaning water. 2.4.3 Compartments in the cargo area adjacent to the cargo tanks shall be arranged for cleaning and gasfreeing by equipment available onboard. 2.4.4 The cargo oil piping shall be arranged for easy cleaning, and an arrangement for gas-freeing shall be provided. 2.4.5 A branch line from the fire main shall be arranged in pipe tunnels housing cargo oil piping. A suitable number of hydrant valves shall be located along the length of the tunnel. The branch line shall be arranged for blank flanging outside the tunnel.

2.5 Ventilation 2.5.1 Pipe tunnel, ballast pump room and similar spaces within the cargo area, where access may be necessary for normal operation and maintenance, shall be equipped with a fixed separate ventilation system. 2.5.2 The capacity of the ventilation systems shall be at least 8 air changes per hour for ballast pump room and spaces normally entered. If cargo piping and equipment is arranged in ballast pump room, or the ballast pumproom is located adjacent to cargo tanks, the ventilation capacity shall be at least 20 air changes per hour. 2.5.3 Spaces not normally entered like cofferdams, double bottoms, pipe tunnels, stools and ballast tanks shall be gasfreeable with a mechanical ventilation system (permanent or portable). The ventilation capacity is normally shall be at least 8 air changes per hour for the spaces mentioned except ballast tanks. 2.5.4 Pump room arranged adjacent to protected slop tank shall be fitted with interlock between electric lighting and ventilation, so arranged that the ventilation shall be in operation before the electrical current supply to the room gets connected.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 67

Part 5 Chapter 5 Section 10

2.3.8 Arrangements required by [2.3.6] and [2.3.7] are not necessary if the ship is fitted with separate cargo pumps in each cargo hold.

3.1 Measurement of hydrocarbon gases 3.1.1 Arrangements shall be made to facilitate measurement of gas concentration in all tanks and other compartments within the cargo area. Measurements shall be made possible from open deck or other easily accessible locations. 3.1.2 The measuring equipment shall be of approved type, and may be fixed or portable except as stated in [3.1.3]. Note however that the requirements in Sec.9 [7.2] apply. 3.1.3 Pipe tunnel and cargo pump room shall be equipped with a fixed hydrocarbon gas detection system with alarm. The system shall cover at least three (3) locations along the length of the tunnel, however, spaced not more than 30 m apart. 3.1.4 Apart from the gas detection arrangements required by [3.1.1] to [3.1.3] the ship shall have two sets of portable gas measuring equipment, each set consisting of one apparatus for measuring O2 content, one apparatus for measuring hydrocarbon contents in the range 0 to 20% hydrocarbon gas by volume and one apparatus for measuring low hydrocarbon gas contents (0 to 100% LEL).

4 Instructions 4.1 Operations manual An operations manual shall be developed covering all essential operational procedures. As a minimum the following shall be included: — — — — — —

Procedures for conversion from tanker trade to dry cargo trade, and vice versa. Procedures for cleaning and gas-freeing of cargo tanks, cargo piping and adjacent spaces. Procedures related to tanker cargo handling operations in port and during voyage. Description and listing of cleaning equipment and its intended use. Procedures for gas monitoring. Actions to be taken when the gas concentration exceeds the defined acceptable limits. Guidance note: The actions to be taken when gas concentrations are exceeded may be repeated ventilation, cleaning and ventilation, inerting, water filling, depending on type of compartment, nature of problem and available equipment. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.2 Instructions onboard Instructions for dry cargo and tanker service shall be permanently posted in cargo control rooms and deck office.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 68

Part 5 Chapter 5 Section 10

3 Gas measuring equipment

1 General 1.1 Application 1.1.1 The requirements in this section apply to inert gas systems for inerting of tanks and void spaces within the cargo area. 1.1.2 Oil carriers (Tanker for oil or Tanker for oil products) of 8000 tons deadweight and above intended for the carriage of oil cargoes having a flash point not exceeding 60°C (closed cup test) and all ships with crude oil washing arrangement regardless of size shall be fitted with a permanently installed inert gas system complying with the rules in this section. Oil carriers (Tanker for oil or Tanker for oil products) less than 8000 tons deadweight fitted with inert gas system complying with the requirements in this section may be assigned the special features notation Inert. Guidance note: The requirements in this section are considered to meet the FSS Code Ch.15 and SOLAS Reg. II-2/ 4.5.5 and II-2/ 11.6.3.4. and as amended by IMO Res. MSC.367 (93). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.3 Oil tankers of 8000 tons deadweight and above constructed on or after 1 January 2016 shall be fitted with a fixed inert gas system, complying with the requirements in this section. Guidance note: Oxygen alarm setting will from the date 01.01.2016 be reduced from 8% to 5%. Reference is also made to IMO Res. MSC.365 (93). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.4 Documentation and certification requirements is found in Sec.1 [4].

1.2 Operation and equipment manual A ship specific operation and equipment instruction manual covering a technical description of the system and equipment, as well as operational safety and health requirements shall be submitted in accordance with Sec.1 Table 5. The manual shall include guidelines on procedures that shall be followed in event of failure of the inert gas system. Guidance note: See also Ch. 8 and Ch.11 of MSC/Circ.353, as amended by MSC/Circ.387. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2 Materials 2.1 General 2.1.1 Materials used in piping systems for inert gas plants shall comply with the requirements specified in Pt.4 Ch.6.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 69

Part 5 Chapter 5 Section 11

SECTION 11 INERT GAS SYSTEMS

2.1.3 Materials shall be selected so as to reduce the probability for corrosion and erosion. Those components which may be subjected to corrosion shall be either constructed of corrosion-resistant material or lined with rubber, glass fibre epoxy resin or other equivalent coating material.

3 Arrangement and general design 3.1 General 3.1.1 The inert gas system shall be capable of supplying a gas or mixture of gases with an oxygen content of not more than 5% at a capacity to satisfy the intended use under all normal operating conditions. The system shall be able to maintain an atmosphere with an oxygen content not exceeding 8% by volume in any part of any cargo tank and at a positive pressure in port and at sea except when it is necessary for such a tank to be gas-free. Inert gas plants based on flue gas from boilers which normally are not in operation during sea voyages (motor ships), and which are not equipped with separate inert gas generator for topping-up purposes, shall be arranged to enable production of flue gas of adequate quantity and quality (artificial load) whenever topping-up shall be carried out. 3.1.2 The inert gas system shall be designed and equipped in such a way as to prevent hydrocarbon gases from reaching non-hazardous spaces, and prevent interconnection between tanks and spaces within the cargo area, which normally do not have such connections, e.g. between segregated ballast tanks and cargo tanks. 3.1.3 The inert gas may be based on flue gas from boilers or from separate inert gas generators with automatic combustion control. 3.1.4 Systems using stored carbon dioxide will not be accepted unless the Society is satisfied that the risk of ignition from generation of static electricity by the system itself is minimised. 3.1.5 Inert gas systems based on other means than combustion of hydrocarbons such as inert gas produced by passing compressed air through hollow fibres, semi-permeable membranes or adsorber materials shall also comply with the requirements of Ch.6 Sec.16. 3.1.6 Inert gas generators based on combustion of fuel, shall be located outside the cargo area. Spaces containing inert gas generators shall have no direct access to accommodation service or control station spaces, but may be located in machinery spaces. When located in a separate compartment, it shall be separated by a gastight steel bulkhead and/or deck from accommodation, service and control station spaces. Where a separate compartment is provided, it shall be fitted with an independent mechanical extraction ventilation system, providing six (6) air changes per hour. Two oxygen sensors (low oxygen alarms) shall be fitted at appropriate locations and give audible and visual alarm both inside the compartment and outside the door. The compartment shall have no direct access to accommodation spaces, service spaces and control station.

3.2 Piping arrangement 3.2.1 The piping arrangement shall allow the cargo tanks to be filled with inert gas during unloading, without having open connection to the atmosphere. 3.2.2 The piping arrangement shall allow cargo tank washing to be carried out in an inert atmosphere.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 70

Part 5 Chapter 5 Section 11

2.1.2 Materials used for other parts of the inert gas plant shall comply with the requirements in applicable chapters of the rules. Works' certificates will be accepted.

Guidance note: With an arrangement utilising the dilution method and inlet at deck level, the diameter and flowrate of inlets should be such that the jet will penetrate all the way down to the tank bottom. Figure 1 may be used for determining the relationship between jet penetration depth inlet diameter and flowrate. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

The exhaust gas outlets shall comply with the requirements for cargo tank venting, see Sec.5 [2]. Connection to cargo oil pipes, see Sec.5 [1]. FLOWRATE M3/HI

25000

DENSITY RATIO TANK CONTENT/ AIR = 1.25

DI AM ET ER

1

d

=

40

0

20000

IN LE T

15000

35

0

30

0

25

10000

0

20 0

15 0

5000

PENETRATION DEPTH (M) 10

20

30

40

50

Figure 1 Relation between flowrate and penetration depth for selected inlet diameters 3.2.4 The inert gas supply main(s) shall be fitted with branch piping leading to each cargo tank. Branch piping for inert gas shall be fitted with either stop valves or equivalent means of control for isolating each tank. Any stop valves fitted shall be provided with locking arrangements. With regard to an arrangement of a common inert gas and vent pipe, see Sec.5 [2]. Each cargo tank not being inerted shall be capable of being separated from the inert gas main by one of the following alternative arrangements: 1)

2) 3)

Removing spool-pieces, valves or other pipe sections, and blanking the pipe ends. The use of fire tested flexible hoses is considered as equivalent to a spool piece provided they are type approved in accordance with IACS P2.12, including fire testing in accordance with IACS P.2.12.5. Fire test is not required for hoses made of steel. Two shutoff valves or two spectacle flanges in series, with an arrangement to vent the space between the valves in a safe manner. A shutoff valve and a spectacle flange in series with an arrangement to vent the space between the valve and the spectacle flange in a safe manner.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 71

Part 5 Chapter 5 Section 11

3.2.3 The supply pipes for inert gas shall be so arranged that the velocity and direction of the jet will facilitate effective change of the tank atmosphere.

If liquid filled pressure/vacuum breaking devices are fitted, means for easy control of the liquid level shall be provided. The liquid shall be operational in the temperature range -20°C to +40°C. 3.2.6 The piping system shall be designed so as to minimize the generation of static electricity. 3.2.7 Arrangements shall be made to allow bow or stern loading and discharge pipes to be purged after use and maintained gas safe when not in use. The vent pipes connected with the purge shall be located in the cargo area. 3.2.8 The piping arrangement shall not allow the main inert gas line to be filled with cargo oil, for example by locating the main inert gas line at sufficient height above the cargo tanks or by installing liquid barriers in the branch lines. 3.2.9 Suitable arrangements shall be provided to enable the inert gas main to be connected to an external supply of inert gas. The arrangements shall be located forward of the non-return valve referred to in [3.6.3].

3.3 Inerting of double hull spaces 3.3.1 On oil tankers required to be fitted with inert gas system, double hull spaces shall be fitted with suitable connections for supply of inert gas. Portable means may be used. Where necessary, fixed purge pipes shall be arranged. Double-hull spaces in the context of this requirement are all ballast tanks and void spaces of double-hull and double bottom spaces adjacent to the cargo tanks, including the forepeak tank and any other tanks and spaces under the bulkhead deck adjacent to cargo tanks, except cargo pump-rooms and ballast pump-rooms. 3.3.2 Where such spaces are connected to a permanently fitted inert gas system means shall be provided to prevent hydrocarbon gases from the cargo tanks entering the double hull spaces through the system, e.g. by using blank flanges.

3.4 Fresh air intakes Fresh air intakes to the inert gas system for gas-freeing of cargo tanks shall be arranged. The air intakes shall be provided with blanking arrangement.

3.5 Level measuring of inerted tanks Means shall be provided to allow ullaging and sounding of inerted tanks without opening the tanks. Separate ullage openings may be fitted as a reserve means.

3.6 Prevention of gas leakage into non-hazardous spaces 3.6.1 An automatically controlled valve shall be fitted near the bulkhead where the main line leaves nonhazardous spaces. The valve shall close automatically when there is no overpressure in the main line after the fans. 3.6.2 The inert gas main line shall have a water seal located in the cargo tank area on deck. The water seal shall prevent the return of hydrocarbon vapour to any non-hazardous spaces under all normal conditions of trim, list and motion of the ship.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 72

Part 5 Chapter 5 Section 11

3.2.5 To protect the tanks from a pressure exceeding design vapour pressure and a vacuum exceeding 0.07 bar, one or more pressure/vacuum breaking devices with sufficient capacity shall be provided in the system. Such device(s) shall be installed on the inert gas main unless such devices are installed in the venting system required by Sec.5, or on individual cargo tanks.

Means for easy control of the level in the sealed condition shall be provided. For oil tankers arranged also for carriage of chemicals an arrangement alternative to the water seal may be considered. 3.6.3 In addition to the water seal, the inert gas main line shall have a non-return valve installed on tank deck between the water seal and the nearest connection of any cargo tank. The non-return valve shall be provided with positive means of closure. As an alternative to positive means of closure, an additional valve having such means of closure may be provided forward of the non-return valve. 3.6.4 Means shall be provided to vent the inert gas main line in a safe manner between the automatically controlled valve and the second closing device on tank deck. 3.6.5 A water loop or other approved arrangement shall also be fitted to all associated water supply and drain piping and all venting or pressure sensing piping leading to non-hazardous spaces. Means shall be provided to prevent such loops from being emptied by vacuum. 3.6.6 The deck water seal and all loop arrangements shall be capable of preventing return of hydrocarbon vapours at a pressure equal to the test pressure of the cargo tanks. 3.6.7 Provision shall be made to ensure that the water seal is protected against freezing, in such a way that the integrity of seal is not impaired by overheating.

4 Inert gas production and treatment 4.1 General 4.1.1 The inert gas scrubber, fans and inert gas generators shall be located aft of all cargo tanks, cargo pump rooms and cofferdams separating these spaces from machinery spaces. 4.1.2 The system shall be capable of delivering inert gas to the cargo tanks at a rate of at least 125% of the maximum rate of discharge capacity of the ship expressed as a volume. The fan capacity shall secure an acceptable positive pressure in the tanks and spaces at any normal operation condition. 4.1.3 At least two fans shall be provided which together will be capable of delivering to the cargo tanks at least the volume of gas required in [4.1.2]. However, no fan shall have a capacity less than one third of the combined fan capacity. In systems with gas generators a single fan may be accepted provided that sufficient spares for the fan and its prime mover are carried on board. 4.1.4 The fan pressure shall not exceed 0.3 bar. If fans with higher pressures are used, it shall be documented that the maximum pressure the inert gas system can exert on any cargo tank does not exceed its design pressure.

4.2 Flue gas system 4.2.1 The flue gas connection from the boilers shall be located before a rotary air preheater, if fitted. 4.2.2 Flue gas isolating valve(s) shall be fitted in the inert gas supply main(s) between the boiler uptake(s) and the gas scrubber. These valves shall be provided with indicators. 4.2.3 In addition to the valve nearest to the boiler uptake a sealing shall be arranged to prevent flue gas leakage when the inert gas system is not in operation.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 73

Part 5 Chapter 5 Section 11

As far as practicable, the water seal shall prevent entrained water in the gas. Provisions shall be made to secure operation of water seal below water freezing temperature.

4.2.5 An interlocking device shall be arranged to prevent starting of sootblowing of the boiler when the valve nearest to the boiler uptake is open. For manual soot blowing, alarm and signboard is acceptable. 4.2.6 Isolating valves shall be fitted on both suction and delivery sides of each fan. 4.2.7 An adequate arrangement shall be provided for cleaning the impeller in place.

4.3 Inert gas generator Two fuel oil pumps shall be fitted to the inert gas generator. Suitable fuel in sufficient quantity shall be provided for the inert gas generators. Guidance note: A complete motor, impeller and bearings for the pump will normally be considered sufficient. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.4 Gas cleaning and cooling A gas scrubber shall be fitted for the purpose of effective cooling and cleaning of the gas. The scrubber shall be protected against corrosion. Devices shall be fitted to minimise carry-over of water and solids. For flue gas system the scrubber shall be fitted on the suction side of the fans.

4.5 Water supply 4.5.1 The gas scrubber shall be supplied with cooling water from two pumps, each of sufficient capacity for supplying the system at maximum inert gas production, and without interfering with any essential service on the ship. One of the pumps shall serve the inert gas scrubber exclusively. 4.5.2 The water seal, if fitted, shall be capable of being supplied by two separate pumps, each of which shall be capable of maintaining an adequate supply at all times.

4.6 Water discharge 4.6.1 The water effluent piping from scrubber, valve(s) included, shall be protected against corrosion. 4.6.2 Distance piece between overboard valve and shell plating shall be of substantial thickness, at least shell plate thickness, but not less than 15 mm. 4.6.3 If water discharge is obtained by means of discharge pumps, a pumping arrangement equivalent to the supply shall be provided. 4.6.4 Discharge pipes from the water seal shall lead directly to sea.

5 Instrumentation 5.1 General The instrumentation shall be in accordance with Pt.4 Ch.9.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 74

Part 5 Chapter 5 Section 11

4.2.4 A permanent arrangement for cleaning the valves nearest to the boiler uptake shall be arranged.

5.2.1 Instrumentation shall be fitted for continuous indication of temperature and pressure of the inert gas at the discharge side of the gas fans, whenever the fans are operating. 5.2.2 Instrumentation shall be fitted for continuous indication and permanent recording, at all times when inert gas is being supplied, the pressure of the inert gas supply mains forward of the non-return devices on tank deck and oxygen content of the gas in the inert gas supply main on the discharge side of the fan. Such instrumentation shall, where practicable, be placed in the cargo control room, if fitted. In any case the instrumentation shall be easily accessible to the officer in charge of cargo operations. 5.2.3 In addition, meters shall be fitted on the navigation bridge to indicate the pressure of the inert gas supply main forward of the non-return devices on tank deck and in the machinery control room or machinery space to indicate the oxygen content of the inert gas in the inert gas supply main on the discharge side of the fans. 5.2.4 Portable instruments for measuring oxygen and flammable vapour concentration shall be provided, see Sec.9 [7]. In addition, suitable arrangement shall be made on each cargo tank and double hull space, such that the condition of the tank atmosphere can be determined using these portable instruments.

5.3 Monitoring 5.3.1 A common alarm connection shall be provided between the local inert gas control panel and the machinery control room or machinery space to indicate failure of the inert gas plant. 5.3.2 The extent of alarm and safety functions shall be in accordance with Table 1. 5.3.3 Monitoring of water supply to water seal and power supply for instrumentation shall also be maintained when the inert gas plant is not in use. 5.3.4 For burner control and monitoring, see Pt.4 Ch.7 Sec.7. Table 1 Control and monitoring of inert gas systems

Failure/ indication

Operational status of the inert gas system

Setting

-

Permanent recording

-

Continuous indication

CCR

Alarm

1)

Shut-down of gas regulating valve

-

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

-

Automatic shut-down of blowers (fans)

-

Activation of doubleblock and 2) bleed

Comment

-

Indication showing that inert gas is being produced and delivered to cargo 6) area .

Page 75

Part 5 Chapter 5 Section 11

5.2 Indication

Operational status of isolation valves between IG main and cargo 7) tanks

Oxygen content 5)

Setting

Permanent recording

Continuous indication

Alarm

1)

Shut-down of gas regulating valve

Automatic shut-down of blowers (fans)

Activation of doubleblock and 2) bleed

Comment

-

-

-

-

-

-

-

Position indication providing open/ intermediate/ close status information in the control panel.

-

CCR

ECR and CCR

-

-

-

-

-

Pressure in IG 4) main

-

CCR

ECR, CCR and Bridge

-

-

-

-

Shall be active also when the IG plant is not in use.

IG supply temperature

-

-

ECR and CCR

-

-

-

-

-

High oxygen 5) content

>5%

-

-

CCR and ECR

X

-

-

The inert gas shall be automatically vented to atmosphere.

Low pressure 4) IG main

<100 mm

-

-

CCR and ECR

-

-

-

-

-

-

-

Shall be independent of the low pressure alarm. I.e. separate pressure transmitter.

-

-

-

-

-

Shall include automatic stop of water supply to the scrubber.

Low-low pressure IG main

High pressure 5) IG main

High water level in scrubber

<50 mm

-

-

CCR or automatic shut-down of cargo pumps with alarm

-

-

-

CCR

-

-

-

CCR

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

X

X

Page 76

Part 5 Chapter 5 Section 11

Failure/ indication

Shut-down of gas regulating valve

Automatic shut-down of blowers (fans)

Activation of doubleblock and 2) bleed

Comment

CCR

X

X

-

-

-

CCR

-

-

-

-

-

-

X

X

-

-

Setting

Permanent recording

Continuous indication

-

-

-

High temperature of inert gas supply

65°C

-

High-high temperature of inert gas supply

75°C

-

Low water pressure/flow to scrubber

Alarm

1)

Low level in deck water seal

-

-

-

CCR

-

-

-

Shall be active also when the IG plant is not in use.

Failure of blowers (fans)

-

-

-

CCR

X

-

-

-

Power failure of the control and monitoring system

-

-

-

CCR and ECR

-

-

-

-

-

Shall be active also when the plant is not in use.

Power failure to oxygen and pressure indicators and recorders

-

-

-

CCR and ECR

-

-

Oxygen level in inert gas room(s)

<19% O2

-

-

Outside space and ECR

-

-

-

Minimum 2 oxygen sensors shall be provided in each space. Visual and audible alarm at entrance to the inert gas room(s).

Power failure of inert gas generator

-

-

-

CCR and ECR

-

-

-

Inert gas generators only.

Failure of burner (flame failure)

-

-

-

CCR and ECR

X

-

-

Inert gas generators only.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 77

Part 5 Chapter 5 Section 11

Failure/ indication

Shut-down of gas regulating valve

Automatic shut-down of blowers (fans)

Activation of doubleblock and 2) bleed

Comment

CCR and ECR

-

-

-

Inert gas generators only.

-

CCR

X

-

X

-

-

-

CCR

-

-

-

-

-

CCR

-

-

-

-

-

-

-

-

-

-

-

X

-

Setting

Permanent recording

Continuous indication

Low fuel oil pressure/flow to burner

-

-

-

Loss of inert gas supply (flow or differential 2) pressure)

-

-

Faulty operation of double-bloack and bleed valves

-

Double-block and bleed valve position Loss of power to double-block and bleed

Alarm

1)

See footnote

3)

.

- = not applicable; X = applicable. 1)

Alarms shall be audible and visible.

2)

Application only for ships with double-block and bleed replacing deck water seals.

3)

Faulty operation of double-block and bleed valves:

— one block valve open and other block valve closde — bleed-valve open and block valves open — bleed valve closed and block valves closed — block valves open when there is no inert gas supply. 4)

A common pressure transmitter is acceptable.

5)

A common oxygen sensor is acceptable.

6)

The indication shall be based on the operational status of the gas regulating valve and on the pressure or flow of the inert gas mains forward of the non-return devices. However, the operational status of the IG system is not considered to require additional indicators and alarms other than those specified in the FSS code. 7)

Limit switches shall be used to positively indicate both open and closed position. Intermediate position status shall be indicated when the valve is in neither open nor closed position.

6 Survey and testing 6.1 Survey 6.1.1 Main components of the inert gas plant shall be surveyed during construction by the surveyor. The gas scrubber and water seal shall be tested for tightness.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 78

Part 5 Chapter 5 Section 11

Failure/ indication

6.2 Testing 6.2.1 All alarm, shutdown and safety devices shall be function tested. 6.2.2 A function test of the plant shall be carried out under normal operating conditions, including actual partial load conditions of boilers. 6.2.3 The capacity of the plant shall be confirmed by direct measurement of the gas flow or indirectly by running against maximum discharge capacity of the cargo oil pumps.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 79

Part 5 Chapter 5 Section 11

6.1.2 After completion, the inert gas installation shall be surveyed by the surveyor.

1 General 1.1 Application 1.1.1 The requirements in this section apply to ships with class notation as given in Sec.10 [1.1].

1.2 Documentation 1.2.1 Documentation shall be submitted in accordance with Sec.1 [4] and Sec.10 [1.3].

2 Arrangement and systems 2.1 Arrangement 2.1.1 Where not bounded by weather decks, pump rooms or fuel oil tanks, the slop tank(s) shall be surrounded by cofferdams. These cofferdams shall not be open to a double bottom, pipe tunnel, pump room or other enclosed space. However, openings provided with gastight bolted covers may be permitted. 2.1.2 Cofferdams shall be arranged for water filling and draining. 2.1.3 Hatches and other openings to slop tanks shall be arranged for locking in closed position.

2.2 Tank venting Slop tanks shall have a separate, independent venting system with pressure/vacuum relief valves. Gas outlets shall have a minimum horizontal distance of 10 m from openings to non-hazardous spaces and exhaust outlet from machinery.

2.3 Pumping and piping system 2.3.1 Pipe connections to slop tanks shall have means for blank flanging on open deck or at another easily accessible location. 2.3.2 Pumping system installed for handling of slop while the ship is in service not covered by the class notation Tanker for oil or Tanker for oil products shall be separated from all other piping systems. Separation from other systems by means of removal of spool pieces may be accepted.

2.4 Gas detection Dry spaces surrounding slop tanks shall be equipped with an approved automatic gas detector system with alarm.

2.5 Protection inside slop tanks 2.5.1 An arrangement for protecting the tank atmosphere by inert gas or similar effective means, shall be provided.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 80

Part 5 Chapter 5 Section 12

SECTION 12 PROTECTED SLOP TANK

2.5.3 Inerting of slop tank(s) shall be possible irrespective of the blank flanging from the rest of the system.

3 Signboards and instructions 3.1 General 3.1.1 Signboards with the following text shall be fitted at hatches and other openings to cargo slop tanks: SHALL BE KEPT CLOSED AND LOCKED DURING HANDLING OF DRY CARGO 3.1.2 Instructions for handling of slop shall be permanently posted in cargo pump room, cargo control room and deck office. The following text shall be included in these instructions: When the ship is on dry cargo service and cargo slop is carried in protected slop tanks, the following items shall be complied with: — All pipe connections to the slop tanks, except vent pipes (and connection to separate slop pumping system) shall be blanked off. — Inert gas branch connections to the slop tanks shall be kept blanked off, except when filling or re-filling of inert gas is going on. — Slop shall be handled from open deck only. — During handling of dry cargo: — all hatches and openings to the slop tanks shall be kept closed and locked — the slop tanks shall be kept filled with inert gas, and the O2-content in the tanks shall not exceed 8% by volume. — The gas detection system in cofferdams surrounding the slop tanks shall be function tested before loading of dry cargo commences.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 81

Part 5 Chapter 5 Section 12

2.5.2 Meter shall be fitted in the navigation bridge to indicate at all times the pressure in the slop tanks whenever those tanks are isolated from the inert gas supply main.

1 General 1.1 Application 1.1.1 Crude oil tankers (Tanker for oil) of 20 000 tons deadweight and above shall be fitted with a crude oil washing arrangement complying with MARPOL Annex I, Reg. 33 and Reg. 35, which refers to Revised Specifications for the Design, Operation and Control of Crude Oil Washing Systems adopted by IMO with Res. A.446 (XI) as amended by A.497 (XII) and A.897 (21). 1.1.2 Crude oil washing installations which are not mandatory according to MARPOL Annex I shall only comply with relevant requirements related to safety given in the specifications referred to in [1.1.1], such as installation of an inert gas system.

1.2 Tank water washing systems 1.2.1 Tank washing water may be supplied by pumps located outside the cargo area provided the connections to the tank washing system is so arranged that they can only be connected to the tank washing system when that system is completely and unmistakably disconnected from the cargo system. The connection arrangements to the tank washing system shall be arranged in the cargo tank area. Where a combined crude oil-water washing supply piping is provided, the piping shall be so designed that it can be drained so far as is practicable of crude oil before water washing is commenced, into a slop tank or a cargo tank. 1.2.2 Tank washing heaters with permanent connections to a cargo system shall be located in the cargo area. 1.2.3 Crude oil tankers below 20 000 tons deadweight, fitted with crude oil washing arrangement complying with design requirements in the specification referred to in [1.1.1] shall comply with the safety aspects of the specification given in [1.1.1]. 1.2.4 On tankers where inerting of cargo tanks is mandatory, tank cleaning machines shall be permanently installed. Guidance note: The requirement is not to be considered as a prohibition to use additional portable washing machines through necessary access openings to enable additional complete washing of cargo tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 82

Part 5 Chapter 5 Section 13

SECTION 13 CARGO TANK CLEANING ARRANGEMENTS

1 List of oil cargoes 1.1 General This list specifies oil cargoes 2) for oil products

1)

which may be carried on ships with class notation Tanker for oil and Tanker

Asphalt solutions — blending stocks — roofers flux — straight run residue. Oils — — — — — — — — — — — — — — — — —

clarified crude oil mixtures containing crude oil diesel oil fuel oil no. 4 fuel oil no. 5 fuel oil no. 6 residual fuel oil road oil transformer oil aromatic oil lubricating oils and blending stocks mineral oil motor oil penetrating oil spindle oil turbine oil.

Distillates — straight run — flashed feed stocks. Gas oil — cracked. Gasoline blending stocks — alkylates — fuel — reformates — polymer — fuel. Gasolines — — — — —

casing head (natural) automotive aviation straight run fuel oil no. 1 (kerosene)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 83

Part 5 Chapter 5 Appendix A

APPENDIX A LIST OF CARGOES

Jet fuels — — — — — — —

JP-1 (kerosene) JP-3 JP-4 JP-5 (kerosene, heavy) turbo fuel kerosene mineral spirit.

Naphtha — solvent — petroleum — heartcut distillate oil. 1) 2)

The list of oils shall not necessarily be considered as comprehensive. Note the limitation with respect to vapour pressure in Sec.1 [1.3.1]. May carry all the listed oil cargoes except crude oil.

2 Cargoes other than oils Cargoes other than oils may be carried by ships with class notation Tanker for oil products as follows: a) b)

OS (other substances), as per IBC code chapter 18 may be carried. No MARPOL requirements apply. Pollution category Z, as per IBC code chapter 18 may be carried by ships which are provided with an NLS certificate. In addition, relevant safety criteria such as possible stricter foam fire extinguishing requirement shall be complied with. Density of the product will need to be considered additionally.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 84

Part 5 Chapter 5 Appendix A

— fuel oil no. 1-D — fuel oil no. 2 — fuel oil no. 2-D.

July 2017 edition

Changes July 2017, entering into force 1 January 2018. Topic

Reference

Description

MED-certification

Sec.1 Table 7

Acceptance for MED-certified gas detection equipment has been included in Sec.1 Table 7.

OCIMF standard

Sec.4 [1.2.1]

Added text to align with OCIMF: Manifold valves and distance pieces or reducers outboard of valves, which are connected directly to the cargo pipeline's shore connection on deck, shall be made of steel and fitted with flanges conforming to ASME B16.5, i.e. be of flanged or fully logged type.

Access requirement in pipe tunnels.

Sec.10 [2.2.3]

Update the rules to adapt to current designs, i.e. removing a requirement for access point.

Tank washing machines

Sec.13 [1.2.4]

Introduced a requirement for fixed tank washing machines, based on current designs and acceptable practice for inerted ships.

Machinery space bulkhead

Sec.4 [2.1.5]

An explanation of the rule text has been made in a guidance note.

Air locks

Sec.6 [2.2.1]

Rule text has been updated based on interpretation of the IEC-code.

Cargo tank venting systems

Sec.5 [2.1.2]

Transferred guidance note into rule text.

Instrumentation

Sec.9 [4]

Transferred guidance note into rule text.

Machinery space bulkhead

Sec.4 [2.1.6]

The tanker rules has been aligned with requirements for bulkhead penetrations in Pt.4 Ch.6. These penetrations have to follow the specified TA-program.

January 2017 edition

Main changes January 2017, entering into force July 2017 • Sec.1 General

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 85

Part 5 Chapter 5 Changes – historic

CHANGES – HISTORIC

• Sec.2 Hull — Sec.2 [2.1]: Requirements to inerting, gas freeing and inspection of small voids within the cargo area have been deleted in order to avoid conflicting requirements compared to the common structural rules.

• Sec.3 Ship arrangement and stability — Sec.3 [2.1.8]: Has been amended so that cleaning and gas-freeing of small voids within the cargo area is not a requirement. — Sec.3 [6.2]: Has been amended to include deck trunks.

• Sec.4 Piping systems in cargo area — Sec.4 [2.2.10]: Reference has been corrected. — Sec.4 [5.2]: Has been amended to be in compliance with IMO MSC/Circ.474/Corr.

• Sec.5 Gas-freeing and venting of cargo tanks — Sec.5 [2.2.13]: Has been amended to reflect USCG-regulations.

• Sec.10 ships for alternate carriage of oil cargo and dry cargo — Sec.10 [2.2.4]: Has been amended to include any stool spaces containing cargo pumps and piping. — Sec.10 [2.2.5]: Access entrances and passages shall have a clear opening in accordance with Sec.3 [4.2].

• Sec.11 Inert gas system — Sec.11 [3.2.4]: Has been amended in accordance with forthcoming IACS unified interpretations to the FSS code. — Sec.11 [3.3.1]: Has been amended to clarify which spaces require inert gas in accordance with IACS UI SC272. — Sec.11 Table 1: Table 1 has been amended in accordance with FSS code amendments and forthcoming IACS unified interpretations to the FSS code.

July 2016 edition

Main changes July 2016, entering into force 1 January 2017 • Sec.1 General — Sec.1 Table 1: Notation Barge for oil included — Sec.1 Table 3: Definition of cargo tank block amended to include extending to the full depth of the ship

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 86

Part 5 Chapter 5 Changes – historic

— Sec.1 Table 3: The definition of cargo area in table 3 has been amended to reflect that it also includes the full depth of the ship. — Sec.1 Table 5: In table 5 regarding internal access, additional description has been updated with correct SOLAS reference. — Sec.1 Table 7: In table 7 a note has been inserted indicating requirements for EC-MED certificates for P/Vvalves on EEA flagged vessels.

— — — —

Material certificate for emergency towing strongpoints changed from Society to manufacturer issuance Certificate for liquid pressure/vacuum breakers changed from manufacturer to Society issuance "Pressure/vacuum valves": The text "For EEA flagged ships EC-MED" has been removed "Pressure/vacuum valves": A note has been included below the table specifying that EC-MED may be required for inert gas components for EEA flagged ships

• Sec.3 Ship arrangement and stability — Sec.3 [3.2.1]: Protection of cargo tanks value corrected from 24 to 2.4

• Sec.4 Piping systems in cargo area — Sec.4 [1.2.1]: The requirement has been changed from flanged type to flanges conforming to ASME B16.5 to avoid misunderstanding with the definition of flanged type valves — Sec.4 [1.4.1]: A requirement stating protection against accidental impact for pipes with aluminium coating, as this is perceived to increase the risk for sparks, has been added — Sec.4 [2.1.3]: It has been clarified that the boundary penetration between cargo tanks is an issue for ships not carrying homogenous cargoes

• Sec.8 Area classification and electrical installations — Sec.8 [3.1.4]: Paragraph with reference to Sec.6 [2] for ventilation has been removed. Remaining paragraphs have been renumbered [3.1.4] to [3.1.6] accordingly

• Sec.11 Inert gas systems — Sec.11 [4.1.4]: The requirement has been amended so that higher fan pressure can be introduced, but only if total pressure exerted on the tanks is below design pressure for said tanks — Sec.11 Table 1: — The comment for "Operational status of the inert gas system" has been amended — Footnote 6) "Indication of position of gas regulating valve is accepted as status of delivery to cargo area" has been deleted

• Sec.12 Protected slop tank — Sec.12 [2.2]: Requirement for gas outlets to have a minimum distance of 6 m above tank deck has been removed from the paragraph

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Amendments January 2016 • General — Only editorial corrections have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.5. Edition January 2018 Oil tankers

DNV GL AS

Page 87

Part 5 Chapter 5 Changes – historic

— Sec.1 Table 7:

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition July 2017

Part 5 Ship types Chapter 6 Chemical tankers

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS July 2017

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the January 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.6. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes July 2017, entering into force 1 January 2018. Topic

Reference

Description

MED requirements alignment

Sec.1 Table 6

Reference to MED requirements as directed by EU requirements has been included in the rule chapter in order to show that MED certification is accepted.

Access to forepeak tank

Sec.6 [1.6]

Rules has been updated to allow access into forepeak ballast tank via upper void if direct access to open deck is fulfilled.

Cargo manifold requirements aligned with OCIMF

Sec.2 [2.3.5]

Added text in order to align with OCIMF: manifold valves and distance pieces or reducers outboard of valves, which are connected directly to the cargo pipeline's shore connection on deck, shall be made of steel and fitted with flanges conforming to ASME B16.5, i.e. be of flanged or fullylugged type.

PV breaker certification requirement errata

Sec.1 Table 6

Table 6 has been updated to reflect that pressure/vacuum breakers shall comply with certification requirements set out in Sec.1 Table 6 i.e. product certificate issued by the Society.

Air lock requirements clarification

Sec.10 [2.2]

Air lock requirements have been aligned with IEC60092-502 standard.

Tank cleaning requirements

Sec.6 [1.1.12]

Introduced a requirement for fixed tank washing machines, based on current designs and acceptable practice for inerted ships.

Machinery space bulkhead

Sec.6 [1.1.5]

An explanation of the rule text has been made in a guidance note.

Machinery space bulkhead

Sec.6 [1.1.6]

The tanker rules have been aligned with requirements for bulkhead penetrations in Pt.4 Ch.6. These penetrations shall follow the specified TA-program.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 3

Part 5 Chapter 6 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................. 10 1 Introduction.......................................................................................10 1.1 Introduction................................................................................... 10 1.2 Scope............................................................................................ 10 1.3 Application..................................................................................... 10 2 Class notations.................................................................................. 11 2.1 Ship type notations.........................................................................11 2.2 Additional notations........................................................................ 12 2.3 Register information........................................................................ 12 2.4 Tank types..................................................................................... 14 2.5 Filling limits for cargo tanks............................................................. 15 2.6 Signboards..................................................................................... 15 2.7 Cargo information........................................................................... 15 2.8 Procedures and arrangements manual............................................... 15 2.9 Definitions......................................................................................16 3 Documentation and certification........................................................ 18 3.1 Documentation requirements............................................................18 3.2 Certification requirements................................................................ 22 4 Testing............................................................................................... 25 4.1 Testing during newbuilding...............................................................25 Section 2 Hull........................................................................................................ 26 1 General.............................................................................................. 26 2 Materials............................................................................................ 26 2.1 Selection and testing.......................................................................26 2.2 Materials for cargo tanks................................................................. 26 2.3 Materials for cargo piping................................................................ 26 3 Strength............................................................................................. 27 3.1 Independent tanks.......................................................................... 27 3.2 Emergency towing.......................................................................... 27 3.3 Vertically corrugated bulkhead without stool.......................................27 3.4 Small confined spaces within or adjacent to cargo tanks...................... 27 4 Fatigue assessment........................................................................... 27 5 Direct strength calculations............................................................... 27

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 4

Part 5 Chapter 6 Contents

CONTENTS

1 Cargo tank location........................................................................... 28 1.1 General..........................................................................................28 2 Location and separation of spaces.....................................................28 2.1 General..........................................................................................28 3 Arrangement of entrances and other openings..................................29 3.1 Accommodation and non-hazardous spaces........................................ 29 3.2 Hazardous spaces and cargo tanks................................................... 30 3.3 Access to and within cargo tanks, void spaces and other spaces in the cargo area...........................................................................................30 4 Protection of crew............................................................................. 31 4.1 Arrangement.................................................................................. 31 5 Cargo pump rooms, cofferdams, pipe tunnels and deck trunks.......... 31 5.1 General..........................................................................................31 6 Diesel engines driving emergency fire pumps, etc............................. 32 6.1 General..........................................................................................32 7 Chain locker and windlass................................................................. 32 8 Anodes, washing machines and other fittings in tanks and cofferdams............................................................................................ 32 9 Slop tanks..........................................................................................32 9.1 Arrangement.................................................................................. 32 10 Stowage of cargo samples............................................................... 33 10.1 General........................................................................................ 33 10.2 Arrangement.................................................................................33 Section 4 Arrangement in hold spaces..................................................................34 1 General.............................................................................................. 34 1.1 Distance between tanks and hull...................................................... 34 2 Gas pressure relief devices................................................................34 2.1 Pressure and vacuum relief valves.................................................... 34 3 Sealing around tanks......................................................................... 34 4 Earth connections.............................................................................. 34 Section 5 Testing of cargo tanks...........................................................................35 1 Requirements for testing of welds and non-destructive testing......... 35 1.1 General..........................................................................................35 1.2 Weld production tests......................................................................35 Section 6 Piping systems in the cargo area.......................................................... 36 1 Piping systems not used for cargo.................................................... 36

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 5

Part 5 Chapter 6 Contents

Section 3 Ship arrangements................................................................................ 28

1.2 Cargo pump rooms......................................................................... 37 1.3 Cofferdams and pipe tunnels............................................................37 1.4 Spaces for independent tanks.......................................................... 37 1.5 Ballast systems.............................................................................. 37 1.6 Forepeak ballast tank...................................................................... 38 1.7 Fuel oil tanks................................................................................. 38 2 Cargo piping system.......................................................................... 39 2.1 General..........................................................................................39 2.2 Cargo pumps..................................................................................39 2.3 Arrangement and general design...................................................... 40 2.4 Pressure indication.......................................................................... 41 2.5 Welding procedure tests.................................................................. 41 2.6 Testing...........................................................................................42 3 Stripping of cargo tank and cargo lines............................................. 42 3.1 General..........................................................................................42 4 Discharge of contaminated water...................................................... 43 4.1 Location of discharge outlet............................................................. 43 4.2 Sizing of the discharge outlet...........................................................43 4.3 Cargo record book and SMPEP......................................................... 43 5 Stern loading and unloading arrangements....................................... 43 5.1 General..........................................................................................43 5.2 Piping arrangement......................................................................... 44 5.3 Accommodation entrances................................................................44 5.4 Electrical equipment — fire fighting...................................................44 6 Cargo hoses....................................................................................... 45 6.1 General..........................................................................................45 Section 7 Cargo heating and cooling arrangements.............................................. 46 1 Cargo heating.................................................................................... 46 1.1 General..........................................................................................46 1.2 Heating of cargoes with temperatures above 80°C.............................. 47 1.3 Cargo cooling system...................................................................... 47 Section 8 Marking of tanks, pipes and valves....................................................... 48 1 General.............................................................................................. 48 1.1 Marking plates................................................................................48 1.2 Pipelines........................................................................................ 48 1.3 Marking of independent tanks.......................................................... 48

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 6

Part 5 Chapter 6 Contents

1.1 General..........................................................................................36

1 Gas freeing of cargo tanks................................................................ 49 1.1 General..........................................................................................49 2 Tank venting systems........................................................................ 50 2.1 General..........................................................................................50 2.2 Tank venting system, type c1 (open)................................................ 50 2.3 Tank venting system, type c2 (controlled)..........................................51 2.4 Tank venting system, type c3 (controlled venting for toxic products)...... 52 Section 10 Mechanical ventilation in the cargo area outside the cargo tanks........ 53 1 System requirements.........................................................................53 1.1 General..........................................................................................53 1.2 Fans serving hazardous spaces.........................................................54 2 Ventilation arrangement and capacity requirements......................... 55 2.1 General..........................................................................................55 2.2 Non-hazardous spaces..................................................................... 55 2.3 Cargo handling spaces.....................................................................55 2.4 Other hazardous spaces normally entered..........................................56 2.5 Spaces not normally entered............................................................56 Section 11 Fire protection and extinction............................................................. 57 1 General.............................................................................................. 57 1.1 Application..................................................................................... 57 2 Fire extinguishing.............................................................................. 57 2.1 Fire extinguishing in cargo area........................................................57 2.2 Deck fire extinguishing system in cargo area......................................57 2.3 Fire extinguishing in cargo pump rooms............................................ 59 Section 12 Area classification and electrical installations..................................... 60 1 General.............................................................................................. 60 1.1 Application..................................................................................... 60 1.2 Insulation monitoring...................................................................... 60 2 Electrical installations in hazardous areas......................................... 60 2.1 General..........................................................................................60 3 Area classification..............................................................................61 3.1 General..........................................................................................61 3.2 Tankers for carriage of products with flashpoint not exceeding 60°C....... 61 3.3 Tankers for carriage of products with flashpoint exceeding 60°C............ 63

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 7

Part 5 Chapter 6 Contents

Section 9 Gas freeing and venting of cargo tanks.................................................49

4 Inspection and testing.......................................................................63 4.1 General..........................................................................................63 5 Maintenance.......................................................................................64 5.1 General..........................................................................................64 6 Signboards......................................................................................... 64 6.1 General..........................................................................................64 Section 13 Instrumentation and automation........................................................ 66 1 General requirements........................................................................ 66 1.1 General..........................................................................................66 2 Alarm, indicating and recording systems........................................... 66 2.1 Cargo tank level gauging................................................................. 66 2.2 Overflow control............................................................................. 67 2.3 Vapour detection.............................................................................67 2.4 Cargo temperature measurement......................................................67 2.5 Leakage alarms.............................................................................. 67 2.6 Computer (PLC) based systems for cargo handling.............................. 67 2.7 Centralised cargo control................................................................. 67 2.8 Integrated cargo and ballast systems................................................ 68 2.9 Gas detection in cargo pump room for flammable liquids with flashpoint not exceeding 60°C............................................................... 68 Section 14 Tests after installation........................................................................ 69 1 General.............................................................................................. 69 1.1 Application..................................................................................... 69 Section 15 Additional requirements for certain cargoes....................................... 70 1 General requirements........................................................................ 70 1.1 Application..................................................................................... 70 1.2 Materials of construction..................................................................70 1.3 Segregation of cargo from bunker tanks............................................ 70 1.4 Separate piping systems..................................................................70 1.5 Cargo contamination....................................................................... 70 1.6 Inert gas....................................................................................... 71 1.7 Moisture control (drying)................................................................. 71 1.8 Cargo pumps in tank...................................................................... 71 1.9 Products not to be exposed to excessive heat.................................... 71 1.10 Cargo pump temperature sensors................................................... 71

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 8

Part 5 Chapter 6 Contents

3.4 Tankers for carriage of products (e.g. acids) reacting with other products/materials to evolve flammable gases......................................... 63

2 Additional requirements for certain groups of products.....................72 2.1 Acids............................................................................................. 72 2.2 Products which have a vapour pressure greater than 1.013 bar at 37.8°C................................................................................................ 72 3 Additional requirements for certain chemicals...................................73 3.1 Ammonium nitrate solution, 93% or less........................................... 73 3.2 Carbon disulphide........................................................................... 73 3.3 Diethyl ether.................................................................................. 73 3.4 Hydrogen peroxide solutions of 60% but not over 70% by mass............73 3.5 Hydrogen peroxide solutions over 8% but not over 60% by mass.......... 73 3.6 Phosphorus, yellow or white.............................................................73 3.7 Propylene oxide and mixtures of ethylene oxid/propylene oxide with ethylene oxide content of not more than 30% by weight........................... 73 3.8 Sulphuric acid.................................................................................76 3.9 Sulphur liquid................................................................................. 77 3.10 Alkyl (C7 - C9) nitrates................................................................. 77 Section 16 Inert gas systems............................................................................... 78 1 General.............................................................................................. 78 1.1 Application..................................................................................... 78 1.2 Documentation............................................................................... 78 2 Materials, arrangement and design................................................... 78 2.1 General..........................................................................................78 2.2 Inert gas systems based on other means than combustion of hydrocarbons....................................................................................... 79 2.3 Nitrogen inert gas systems fitted for other purposes........................... 80 3 Instrumentation.................................................................................81 3.1 General..........................................................................................81 Section 17 Personnel protection........................................................................... 85 1 General requirements........................................................................ 85 1.1 Protective equipment.......................................................................85 2 Safety equipment...............................................................................85 2.1 Safety equipment........................................................................... 85 3 Medical first-aid equipment............................................................... 86 3.1 General..........................................................................................86 4 Decontamination showers and eye washes....................................... 86 4.1 General..........................................................................................86 Changes – historic................................................................................................ 87

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 9

Part 5 Chapter 6 Contents

1.11 Increased ventilation of cargo handling spaces..................................72

1 Introduction 1.1 Introduction These rules apply to ships intended for carriage of liquid chemicals in bulk.

1.2 Scope 1.2.1 The requirements of this chapter are considered to meet the requirements of the international code for the construction and equipment of ships carrying dangerous chemicals in bulk (IBC code) and MARPOL 73/78 Annex II. 1.2.2 Machinery installations and their auxiliary systems that support cargo handling shall meet the same rule requirements as if they were considered to support a main function, see Pt.1 Ch.1 Sec.1 [2.1].

1.3 Application 1.3.1 Cargoes covered by the classification in accordance with this chapter are considered to be those listed in the IBC code chapter 17 and 18 and the agreed additions given in the latest IMO MEPC.2/Circ.xx List 1. Non-hazardous cargoes except oil, are covered by the general requirements for main class unless otherwise stated. 1.3.2 Chemical tankers also intended for carriage of oil shall comply with the requirements in Ch.5. 1.3.3 The requirements in this chapter are supplementary to those given for assignment of main class. 1.3.4 Simultaneous carriage of dry cargo (including vehicles and passengers) and liquid chemicals in bulk with flashpoint not exceeding 60°C is not permitted for ships with class notations as stated in [2.1]. 3

1.3.5 For cargo tanks intended for cargoes with specific gravity exceeding 1025 kg/m , see made to Pt.6 Ch.1 Sec.3. 1.3.6 These rules apply to ships intended for carriage of liquid chemicals in bulk with a flash point not exceeding 60°C (closed cup test), as well as ships heating its cargo to within 15°C or more of its flashpoint. 1.3.7 For other ships intended for carriage of liquid chemicals in bulk that are non-flammable or have a flashpoint exceeding 60°C, the requirement will be specially considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 10

Part 5 Chapter 6 Section 1

SECTION 1 GENERAL

2.1 Ship type notations Vessels built in compliance with the requirements specified in Table 1 will be assigned with the class notations as follows: Table 1 Ship type notations Class notation

Description

Application

Design requirements, rule reference

Tanker for chemicals

Ships designed for carriage of all types of liquid chemicals.

Chemical carriers. Cargoes listed in IBC code ch. 17 and 18 with additions given in IMO MEPC.2/Circ.xx List 1.

Sec.1 to Sec.14.

Tanker for C

Ships designed for carriage of specific types of liquid chemicals. C denotes the type of cargo for which the ship is classed.

Chemical carriers. Cargoes not requiring full compliance with Sec.1 to Sec.14. Chemical carriers according to the IBC code.

Requirements will be considered in each case depending on the nature of the cargo carried.

Tanker for chemicals with flashpoint above 60°C

Ships carrying non-flammable liquid chemicals or liquid chemicals with flashpoint above 60°C and which are not heated to within 15°C or more of its flashpoint.

Ships built in compliance with [1.3.6] and [1.3.7].

Requirement will be considered in each case depending on the nature of the cargo carried.

Barge for chemicals

Barge designed for carriage of all types of liquid chemicals.

Chemical carriers. Cargoes listed in IBC code ch.17 and 18 with additions given in IMO MEPC.2/Circ. xx. List 1.

Sec.1 to Sec.14.

Barge for C

Barge designed for carriage of specific types of liquid chemicals. C denotes the type of cargo for which the ship is classed.

Chemical carriers. Cargoes not requiring full compliance with Sec.1 to Sec.14. Chemical carriers according to IBC code.

Requirements will be considered in each case depending on the nature of the cargo carried.

Barge for chemicals with flashpoint above 60°C

Barge carrying non-flammable liquid chemicals or liquid chemicals with flashpoint above 60°C and which are not heated to within 15°C or more of its flashpoint.

Barge built in compliance with [1.3.6] and [1.3.7].

Requirement will be considered in each case depending on the nature of the cargo carried.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 11

Part 5 Chapter 6 Section 1

2 Class notations

Vessels built in compliance with the requirements specified in Table 2 will also be assigned the mandatory survey arrangement notations as follows: Table 2 Additional notations Class notation

Description

Application Mandatory for ships with class notations: Tanker for chemicals Tanker for C Tanker for chemicals with flashpoint above 60°C

ESP

Enhanced survey programme.

Barge for chemicals Barge for C Barge for chemicals with flashpoint above 60°C and having integral tanks intended for carriage of liquid chemicals in bulk in accordance with the IBC code.

Tanks or holds strengthened for heavy liquid, where (r) 3 denotes the maximum density in t/m in any of the cargo tanks.

HL(ρ)

Tankers.

ETC

Arranged for effective tank cleaning.

CCO

Centralised operation of cargo and ballast handling system. (1)

VCS

Systems for control of vapour emission from cargo tank and in compliance with IMO MSC/Circ.585.

Systems for control of vapour emission from cargo tanks and (2) in compliance with IMO MSC/Circ.585 and USCG CFR 46 part 39. (3)

Tanker for oil, Tanker for oil products, Tanker for chemicals

Systems for onboard vapour processing with a minimum recovery rate of 78% of non-methane VOC.

(B) Additional requirements for vapour balancing.

For vessels with class notation VCS(1), or VCS(2).

For a full definition of all additional class notations, see Pt.1 Ch.2.

2.3 Register information 2.3.1 In the register of vessels classed with the Society, a vessel with the class notation Tanker for chemicals may be given a series of letters and numbers describing technical features of the ship as described in Table 3.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 12

Part 5 Chapter 6 Section 1

2.2 Additional notations

Example: A ship has lowest and highest technical standard in tank groups as follows: Ship type 3, a1, b2, c2, f1, str 0.075 and Ship type 2, a2, b3, c3, f2 str 0.075. In the register of ships the following will be given: Ship type 2, a1.2, b2.3, c2.3, f1.2, str 0.075. Where more than one number is given in connection with a letter, all first and second numbers shall be combined, respectively. Table 3 Optional notations related to design features

Technical feature

Notation/letter Ship type 1

ship type

Ship type 2 Ship type 3

tank type (a)

tank vent system (c)

The notations identify the damage stability standard in accordance with IMO's IBC code.

Design requirements, rule ref.

Sec.3 [1]

a1

Integral tank, type a1.

a2

Integral tank, type a2.

a3

Independent tank, type a3.

a4

Independent tank, type a4.

ssp

Cargo piping and all equipment in contact with cargo and cargo vapours is made of stainless steel.

N/A

ss

Ship has one or more cargo tanks made of stainless steel, solid or clad, and that the pertaining cargo piping and all equipment in contact with cargo and cargo vapours is made of stainless steel.

N/A

b1

Open device.

b2

Restricted device.

b3

Closed device.

b4

Indirect device.

c1

Open type vent system.

c2

Tank vent system, outlet 6 m above deck.

c3

Tank vent system, outlet B/3, minimum 6 m above deck, alternatively 3 m above deck and high velocity valves.

materials of construction

liquid level gauging devices for cargo tanks (b)

Description

[2.4]

Sec.13

Sec.9

Guidance note: Register notation (v) to indicate ventilation capacity

ventilation system (v)

v

in cargo handling spaces (v2/v3 for 30/45 air changes per hour respectively), has been taken out of use.

N/A

---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

overflow control (f)

f1

High level alarm.

f2

High-high level alarm.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Sec.13

Page 13

Part 5 Chapter 6 Section 1

2.3.2 Ship type and tank groups may be indicated in the register of vessels classed with the Society. This will, for a ship with cargo tanks of different technical standard, be limited to the groups with the lowest and highest technical standard, respectively.

Notation/letter

Design requirements, rule ref.

Description 3

Residue quantity not in excess of 0.075 m cargo stripping efficiency (str) of the cargo stripping arrangements of a cargo tank and associated cargo piping

Guidance note: Register notations for stripping efficiency according to

str 0.075

previous MARPOL 73/78 Annex II requirements, were

Sec.6

str 0.3 and str 0.1 for residue quantity not in excess 3

3

of 0.3 m and 0.1 m respectively. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

cofferdam (k)

k

Bunker tanks are separated from cargo tanks by cofferdams.

N/A

2.4 Tank types 2.4.1 Integral tanks, general Integral tanks form a part of the ship's hull and are influenced in the same manner and by the same loads which stress the adjacent hull structure. The design vapour pressure p0 is normally not to exceed 0.25 bar. If, however, the hull scantlings are increased accordingly, p0 may be increased to a higher value but less than 0.7 bar. 2.4.2 Integral tanks, type a1 Integral tanks type a1 are built in such a way that the cargo is separated from the sea by a single skin. 2.4.3 Integral tanks, type a2 Integral tanks type a2 are built in such a way that the cargo is separated from the sea by a double skin. The distance between the ship’s shell plating (bottom and side) shall comply with the distances given in Sec.3 [1.1.1] for Ship type 1 and Sec.3 [1.1.2] for Ship type 2. Guidance note: If a cargo tank is positioned adjacent to a sea chest, a loading restriction for water reactive cargoes will be given on the international certificate of fitness for the carriage of dangerous chemical in bulk. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.4.4 Independent tanks, general Independent tanks do not form a part of the ship's hull. An independent tank is built and installed in such a way that the influence on the tank by the hull's deformation and stresses is minimised. An independent tank does not contribute to the hull strength. An independent tank is normally to have longitudinally rigid fixture to the ship in only one transverse plane. Distance between tanks and hull: see Sec.4 [1.1]. 2.4.5 Independent tanks, type a3 Independent tanks type a3 are self-supporting tanks with a design vapour pressure p0 not exceeding 0.7 bar. 2.4.6 Independent tanks, type a4 Independent tanks type a4 tanks are self-supporting pressure vessels with a design vapour pressure higher than 0.7 bar and where the internal pressure is carried mainly as tensile membrane stresses in the tank skin (cylinders, spheres, etc.).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 14

Part 5 Chapter 6 Section 1

Technical feature

Tanks for liquid cargo shall be so loaded as to avoid the tank becoming liquid full during the voyage taking into consideration the highest temperature which the cargo may reach.

2.6 Signboards Signboards are required by the rules for: — Sec.3 [5.1.1] regarding plates bolted to boundaries facing the cargo area and which can be opened for removal of machinery. These shall be fitted with signboard giving instructions that the plates shall be kept closed unless ship is gas-free. — Sec.8 [1.3] regarding marking plates for independent tanks. — Sec.10 [2.3.2] regarding pumps and compressors which shall not be started before the ventilation system in the electric motor room has been in operation for 15 minutes. — Sec.12 [6.1.1] regarding opening of a lighting fitting. Before opening, its supply circuit shall be disconnected. — Sec.12 [6.1.2] regarding ventilation that shall be in operation before lighting gets turned on. — Sec.12 [6.1.3] regarding portable electrical equipment supplied by flexible cables. This equipment shall not be used in areas where there is gas danger. — Sec.12 [6.1.4] regarding welding apparatus. These shall not be used unless the working space and adjacent spaces are gas-free.

2.7 Cargo information 2.7.1 A copy of the international code for construction and equipment of ships carrying dangerous chemicals in bulk, provisions of this code, shall be on board every ship covered by this code. 2.7.2 Information shall be on board, and available to all concerned, giving the necessary data for the safe carriage of the cargo. Such information should include a cargo stowage plan, kept in an accessible place, indicating all cargo on board, including each dangerous chemical carried: 1) 2) 3) 4) 5) 6)

a full description of the physical and chemical properties, including reactivity, necessary for the safe containment of the cargo action that shall be taken in the event of spills or leaks countermeasures against accidental personal contact fire-fighting procedure and fire-fighting media. procedures for cargo transfer, tank cleaning, gas-freeing and ballasting For those cargoes required to get stabilized or inhibited, the cargo should be refused if the certificate required by these paragraphs is not supplied.

2.8 Procedures and arrangements manual 2.8.1 Each ship shall be provided with a Procedures and Arrangements Manual (P & A Manual) developed for the ship in accordance with MARPOL Annex II, Appendix 4 - standard format for the procedures and arrangements manual, and approved by the Society. 2.8.2 Each ship shall be fitted with equipment and arrangements identified in its P & A Manual.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 15

Part 5 Chapter 6 Section 1

2.5 Filling limits for cargo tanks

2.9.1 Terms Table 4 Definitions Terms

Definition

accommodation spaces

spaces used for public spaces, corridors, lavatories, cabins, offices, barber shops, hospital, cinemas, games and hobby rooms, pantries containing no cooking appliances and similar spaces Public spaces are those portions of the accommodation which are used as halls, dining rooms, lounges and similar permanently enclosed spaces.

air lock

enclosed space for entrance between a hazardous area on open deck and a nonhazardous space, arranged to prevent ingress of gas to the non-hazardous space

boiling point

temperature at which a liquid exhibits a vapour pressure equal to the atmospheric barometric pressure

cargo area

part of the ship that contains cargo tanks, slop tanks, cargo pump rooms including pump rooms, cofferdams, ballast or void spaces adjacent to cargo tanks or slop tanks and also deck areas throughout the entire length, breadth and depth of the part of the ship over the above mentioned spaces Where independent tanks are installed in hold spaces, cofferdams, ballast or void spaces at the after end of the aftermost hold space or at the forward end of the forward-most hold space are excluded from the cargo area.

cargo control room

space used in the control of cargo handling operations

cargo handling spaces

cargo pump rooms and other enclosed spaces which contain fixed cargo handling equipment, and similar spaces in which work is performed on the cargo. It includes enclosed spaces containing cargo handling systems where cargo liquid, residue or vapour will be present during operation

cargo handling systems

piping systems in which cargo liquid, vapour or residue is transferred or likely to occur in operation and includes systems such as cargo pumping systems, cargo stripping systems, drainage systems within the cargo area, cargo tank venting systems, cargo tank washing systems, inert gas systems, vapour emission control systems and gas freeing systems for cargo tanks

cargo pump room

space containing pumps and their accessories for the handling of the products covered by the IBC code

cargo tank

liquid-tight shell designed for functioning as the primary container of the cargo. This includes also slop tanks, residual tanks and other tanks containing cargo

cargo tank block

part of the ship extending from the aft bulkhead of the aft-most cargo tank and to the forward bulkhead of the forward most cargo tank, extending to the full beam and depth of the ship, but not including the area above the deck of the cargo tank

cofferdam

isolating space between two adjacent steel bulkheads or decks. The space may be a void space or ballast space

control stations

spaces in which the ship’s radio or main navigating equipment or the emergency source of power is located or where the fire recording or fire control equipment is centralised. Spaces where the fire recording or fire control equipment is centralized are also considered to be a fire control station

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 16

Part 5 Chapter 6 Section 1

2.9 Definitions

Definition

design vapour pressure p0

maximum gauge pressure at the top of the tank which has been used in the design of the tank

flame screen

flame arrester, consisting of a fine-meshed wire gauze of corrosion-resistant material

hazardous area

area in which an explosive gas atmosphere is or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of electrical apparatus Hazardous areas are divided into zone 0, 1 and 2 as defined below and according to the area classification specified in Sec.12 [3]. — zone 0 Area in which an explosive gas atmosphere is present continuously or is present for long periods. — zone 1 Area in which an explosive gas atmosphere is likely to occur in normal operation. — zone 2 Area in which an explosive gas atmosphere is not likely to occur in normal operation and, if it does occur, is likely to do so only infrequently and will exist for a short period only.

high velocity vent valve

cargo tank vent valve which at all flow rates expels the cargo vapour upwards at a velocity of at least 30 m/s, measured at a distance equal to the nominal diameter of the standpipe above the valve outlet opening

hold space

space in which an independent cargo tank is situated

independent system

system not connected other systems and not having provisions available for potential connection to other systems

length (L)

96% of the total length on a waterline at 85% of the least moulded depth measured from the top of the keel, or the length from the foreside of the stem to the axis of the rudder stock on that waterline, if that be greater In ships designed with a rake of keel, the waterline on which this length is measured shall be parallel to the designed waterline. The length (L) shall be measured in metres.

lining

acid-resistant material that is applied to the tank or piping system in a solid state with a defined elasticity property (see IACS UI CC6 Rev. 1)

liquid cargo

cargo with a vapour pressure below 2.75 bar absolute at 37.8°C

non-hazardous area

area not considered to be hazardous

pressure-vacuum (P/V) valve

valve which keeps the tank overpressure or under-pressure within approved limits

public spaces

portions of the accommodation which are used for halls, dining rooms, lounges and similar permanently enclosed spaces

pump room

space located in the cargo area, containing pumps and their accessories for the handling of ballast and oil fuel

reference temperature

temperature corresponding to the vapour pressure of the cargo at the set pressure of the cargo tank pressure relief valve, for the purpose of cargoes with high vapour pressure (see IBC code chapter 15.14)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 17

Part 5 Chapter 6 Section 1

Terms

Definition

residual tank

tank particularly designated for carriage of cargo residues and cargo mixtures typically transferred from slop tanks, cargo tanks and cargo piping Residual tanks which are intended for this storage of cargo or cargo residue shall comply with the requirement for cargo tanks.

separate cargo system

cargo piping system or cargo vent system not connected to other cargo systems This separation may be achieved by the use of design or operational methods. Operational methods shall not be used within a cargo tank and shall consist of one of the following types: — removing spool pieces or valves and blanking the pipe ends — arrangement of two spectacle flanges in series with provisions for detecting leakage into the pipe between the two spectacle flanges.

service spaces

spaces used for galleys, pantries containing cooking appliances, lockers, mail and specie rooms, store rooms, workshops other than those forming part of the machinery spaces and similar spaces and trunks to such spaces

slop tanks

tanks particularly designated for the collection of tank draining, tank washing and other cargo mixtures Slop tanks which are intended for the carriage of cargo or cargo residue shall comply with the requirement for cargo tanks.

spaces not normally entered

cofferdams, double hull spaces, duct keels, pipe tunnels, stool tanks, spaces containing cargo tanks and other spaces where cargo may accumulate

spark arrester

device preventing sparks from the combustion in prime movers, boilers etc. from reaching the open air

tank deck

the following decks are designated tank deck: — deck or part of a deck which forms the top of a cargo tank — part of a deck upon which cargo tanks, cargo tank hatches, valves, pumps or other equipment intended for loading, discharging or transfer of the cargo, are located — part of a deck within the cargo area which is located lower than the top of a cargo tank — deck or part of deck within the cargo area, which is located lower than 2.4 m above a deck as described above

tank types

see [2.4]

void space

enclosed space in the cargo area external to a cargo containment system, not being a hold space, ballast space, fuel oil tank, cargo pump or compressor room, or any space in normal use by personnel

3 Documentation and certification 3.1 Documentation requirements 3.1.1 Tanker for chemical and Tanker for C Documentation shall be submitted as required by Table 5. The documentation will be reviewed by the Society as a part of the class contract.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 18

Part 5 Chapter 6 Section 1

Terms

Object

Internal access

Documentation type H200 – ship structure access manual

Additional description

Info

The plan shall include details enabling verification of compliance with requirements for safe access to cargo tanks, ballast tanks, cofferdams and other spaces within the cargo area as required by IBC code – 3.4.

AP

Including: — cargo hatches, butterworth hatches and any other openings to cargo tanks — doors, hatches and any other openings to pump rooms and other hazardous areas

General arrangement

Z010 – general arrangement plan

— ventilating pipes and openings for cargo hatches, pump rooms and other hazardous areas — doors, air locks, hatches, ventilating pipes and openings, hinged scuttles which can be opened, and other openings to non-hazardous spaces adjacent to the cargo area including spaces in and below the forecastle

FI

— cargo pipes and gas return pipes over the deck with shore connections including stern pipes for cargo discharge or pipes for bow loading arrangement. Hazardous area classification

Electrical equipment in hazardous areas

Ventilation systems for hazardous cargo areas

G080 – hazardous area classification drawing

AP

E170 – electrical schematic drawing

Single line diagrams for all intrinsically safe circuits, for each circuit including data for verification of the compatibility between the barrier and the field components.

AP

Z030 – arrangement plan

Where relevant, based on an approved hazardous area classification drawing where location of electric equipment in hazardous area is added (except battery room, paint stores and gas bottle store).

AP

Z163 – maintenance manual

As specified in Sec.12.

AP

S012 – ducting diagram (DD)

AP

S030 – capacity analysis

AP

C030 – detailed drawing

Rotating parts and casing of fans. Portable ventilators and drawing showing where and how these shall be fitted.

I200 – control and monitoring system documentation

Pollution prevention

AP

AP

S160 – shipboard marine pollution emergency plan (SMPEP)

Applicable when GT ≥ 150.

AP

S010 – piping diagram (PD)

Arrangement and location of underwater discharge outlet(s) including piping system connections to cargo system shall include calculations related to size.

AP

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 19

Part 5 Chapter 6 Section 1

Table 5 Documentation requirements

Documentation type

Cargo pumps and remotely operated valves control and monitoring system vapour return systems

Cargo tanks gasfreeing systems

Developed in accordance with MARPOL, Annex II, Appendix 4 – standard format for the procedures and arrangements manual.

AP

Z250 – procedure

Stripping test procedure.

AP

S010 – piping diagram (PD)

Including cargo stripping system. For vacuum stripping systems, details shall include termination of air pipes and openings from drain tanks and other tanks. For ships with cargo pumprooms, specification of temperature monitoring equipment for cargo pumps and shaft penetrations shall be included in addition to arrangement of drainage of cargo pumps and piping on the pump room.

AP

C030 – detailed drawing

Cargo pump(s).

AP

M010 – material specification, metals

Yard’s declarations of materials in contact with cargo.

AP

Z161 – operational manual

For propylene oxide cargo only. To include filling limit surveys.

AP

C030 – detailed drawing

Gastight bulkhead stuffing boxes, including details of lubrication arrangement and temperature monitoring.

AP

S010 – piping diagram (PD) I200 – control and monitoring system documentation

Cargo tanks level measurement system, fixed

AP For ships with cargo pumprooms, specification of temperature monitoring equipment for cargo pumps and shaft penetrations shall be included.

S010 – piping diagram (PD)

AP

AP

S010 – piping diagram (PD)

Serving cargo tanks and cargo pipes. To include types of connections and location of gas-freeing outlets. For fixed gas freeing fan units, location and means for prevention of backflow shall be included.

C030 – detailed drawing

For systems involving fixed gas freeing fan units, detailed drawings of rotating parts and casing of fans.

Cargo tank drying S010 – piping diagram (PD) systems

Cargo tanks venting system

Info

S140 – procedures and arrangement plan

Cargo piping system

Cargo handling arrangements

Additional description

AP

Only applicable for fixed systems.

AP

S010 – piping diagram (PD)

including settings of P/V-devices and type of gasfreeing outlets

AP

Z030 – specifications

For P/V-valves, gas freeing covers and other flame arresting elements. Detail drawings, specification of maximum experimental safety gap (mesg), flow curves and references to type approval certificates.

FI

I200 – control and monitoring system documentation Z030 – arrangement plan

AP Shall indicate type and location level indicators.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

FI

Page 20

Part 5 Chapter 6 Section 1

Object

Cargo tanks level alarm system, fixed

Documentation type

Additional description

I200 – control and monitoring system documentation

Info AP

Z030 – arrangement plan

Shall indicate type and location of sensors, as well as location of audible and visible alarms.

FI

I200 – control and monitoring system documentation

If required as a secondary mean of cargo tank venting as per Sec.9.

AP

Z030 – arrangement plan

Shall indicate type and location of sensors, as well as location of audible and visible alarms.

FI

Cargo temperature monitoring system

I200 – control and monitoring system documentation

If required by Sec.7.

AP

Cargo heating system

S010 – piping diagram (PD)

Cargo tank

H120 – protection cargo tank location

In accordance with IBC code, ch.2.

AP

S010 – piping diagram (PD)

As required by Pt.4 Ch.6 but shall also include bilge and drainage piping systems serving e.g. pump rooms, cofferdams, pipe tunnels and other dry spaces within cargo area. The drawing shall include arrangement for transfer of sludge/bilge water to slop tanks if installed. The drawing shall also include number and location of any bilge level sensors.

AP

S010 – piping diagram (PD)

As required by Pt.4 Ch.6 but shall also include ballast systems serving ballast tanks in the cargo area. The diagram shall include piping arrangement for forepeak tank (if connected to the ballast system serving the cargo area) as well as details related to ballast treatment systems if installed. For ships with cargo pumprooms, specification of temperature monitoring equipment for ballast pumps and shaft penetrations shall be included.

AP

S010 – piping diagram (PD)

inert gas distribution to cargo tanks, ballast tanks and cargo piping. Shall include connections to e.g. cargo tank venting and vapour return systems

AP

Cargo tanks pressure monitoring system, fixed

Bilge system

Ballast system

AP

— non-return valves — deck water seals S030 – piping diagram (PD)

— double-block and bleed arrangements

AP

— scrubbers

Inert gas system

— P/V breakers. S010 – piping diagram (PD)

Piping systems serving the inert gas unit such as compressed air, exhaust gas, fuel supply, water supply and discharge piping.

AP

Z161 – operation manual

See Ch.8 and 11 of MSC/Circ.353, as amended by MSC/Circ.387.

AP

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 21

Part 5 Chapter 6 Section 1

Object

Documentation type

Inert gas generator

Z100 – specification

Inert gas control and monitoring system

I200 – control and monitoring system documentation

Cargo tanks cleaning systems

Cargo cooling systems

Flammable gas detection systems

Decontamination shower and eye washer

Cargo tanks

Additional description If installed. Also applicable for nitrogen generators.

Info AP

AP

S010 – piping diagram (PD)

The drawing shall show number of and location of cargo tank washing machines.

AP

S110 – shadow diagram

Only applicable for ETC notation.

AP

Z030 – arrangement plan

Washing machines including installation and supporting arrangements.

AP

S010 – piping diagram (PD)

If installed onboard.

AP

Z030 – arrangement plan

Shall include arrangement of sampling piping, location of sampling points, detectors, call points and alarm devices.

AP

I200 – control and monitoring system documentation

Applicable for permanent systems. E.g. as required for cargo pump rooms.

S010 – piping diagram (PD)

With water supply and arrangement to prevent freezing.

AP

Z030 – arrangement plan Z030 – arrangement plan

FI

H131 – non-destructive testing(NDT) plan

AP

H132 – tank testing plan

FI

M010 – material specification, metals

For stainless steel and tanks with lining.

FI

H050 – structural drawing

Support and anti-flotation arrangement (for independent tanks only).

AP

H080 – strength analysis

Stress analysis (for independent tanks type a4 only).

FI

AP = for approval; FI =for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

3.1.2 For general requirements on documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. 3.1.3 For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 3.1.4 Other plans, specifications or information may be required depending on the arrangement and the equipment used in each separate case.

3.2 Certification requirements 3.2.1 Products shall be certified as required in Table 6.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 22

Part 5 Chapter 6 Section 1

Object

Certificate type

Issued by

PC

Society

MC

manufacturer

PC

Society

MC

manufacturer

P/V-valves, gas freeing valves and other flame arresting elements

TA

Society

Cargo pumps

PC

Society

Cargo tanks gas-freeing fans

PC

Society

Ventilation fans for hazardous areas

PC

Society

Hydrocarbon gas detection and alarm system, fixed

PC

Society

Cargo valves and pumps control and monitoring system

PC

Society

Cargo tanks level monitoring system

PC

Society

Cargo tanks overflow protection alarm system

PC

Society

Cargo tanks pressure monitoring alarm system

PC

Society

If required as a secondary mean of cargo tank venting as per Sec.9.

Cargo tank temperature monitoring system

PC

Society

If required by Sec.13 [2.4].

Portable gas detectors

TA

Society

See Sec.13.

Inert gas blowers

PC

Society

Inert gas generators

PC

Society

Scrubbers

PC

Society

Deck water seals

PC

Society

Scrubber sea water supply pumps

PC

Society

Deck water seal sea water supply pumps

PC

Society

Object Emergency towing strong points Emergency towing fairleads

Certification 1) standard

Part 5 Chapter 6 Section 1

Table 6 Certification requirements Additional description

Including stripping pumps.

Permanently installed fans.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 23

Issued by

Certification 1) standard

Pressure/vacuum breakers

PC

Society

Inert gas control and monitoring system

PC

Society

membrane separation vessels

PC

Society

Pressure vessels for nitrogen generators.

Air compressor ≤ 100 kW

PC

manufacturer

Nitrogen generators.

Air compressor > 100 kW

PC

Society

Nitrogen generators.

Control and monitoring system

PC

Society

Nitrogen generators. To include doubleblock and bleed arrangements if fitted.

Additional description

Associated electrical equipment (motors, switchgear and control gear and frequency converters) serving an item that is required delivered with a product certificate issued by the Society is also required to have a product certificate issued by the Society. Such electrical equipment is regarded as important equipment, see Pt.4 Ch.8 Sec.1 [2.3.2]. For EEA flagged ships, EC-MED may be required for inert gas components, fixed hydrocarbon gas detection and alarm systems and portable gas detectors, PV valves and other flame arresting elements. 1)

Unless otherwise specified, the certification standard is the Society's rules.

3.2.2 Documentation of material quality and testing for cargo piping Materials used in cargo piping systems shall be supplied with documentation according to Table 7. Table 7 Documentation of material quality and testing for cargo piping

Issued by

Cargo pipes and heating coils, including fittings made from pipe

PC

Society

pressure

PC

manufacturer

open ended

Flanges and bolts

TR

manufacturer

MC

manufacturer

TR

manufacturer

TR

manufacturer

MC

manufacturer

TR

manufacturer

TR

manufacturer

Bodies of valves and fittings, pump housings, source materials of steel expansion bellows, other pressure containing components not considered as pressure vessels

1)

Certification 1) standard

Additional description

Certificate type

Object

material

steel, nodular cast-iron grade 1 and 2

copper alloys

piping system

nominal diameter [mm]

pressure

> 100

pressure

< 100

open ended pressure

> 50

pressure

< 50

open ended

Unless otherwise specified, the certification standard is the Society's rules.

PC = product certificate, MC = material certificate, TR = test report

3.2.3 For general certification requirements, see Pt.1 Ch.3 Sec.4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 24

Part 5 Chapter 6 Section 1

Certificate type

Object

4 Testing 4.1 Testing during newbuilding 4.1.1 Testing requirements for cargo piping are given in Sec.6 [2.6]. 4.1.2 Testing requirements for cargo tanks are given in Sec.5. 4.1.3 Survey testing requirements for electrical installations are given in Sec.12 [4]. 4.1.4 Survey and test requirements for inert gas systems are given in Sec.16. 4.1.5 Testing requirements for materials of strong points for emergency towing are given in Sec.2 [3.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 25

Part 5 Chapter 6 Section 1

3.2.4 For a definition of the certificate types, see Pt.1 Ch.3 Sec.5.

1 General Requirements for the strength of the hull structure and selection of hull materials shall follow the principles given in Pt.3, supplemented by the requirements given in this section. For scantlings and testing of tanks other than integral tanks, see Ch.5 Sec.7.

2 Materials 2.1 Selection and testing 2.1.1 Where stainless steel in cargo tanks is required for the carriage of particular cargoes, the content of molybdenum in the material shall not be less than 2.5% if type VL 316 L or VL 316 LN is specified. 2.1.2 Clad steel will be accepted if the requirements of Pt.2 Ch.4 Sec.3 and Pt.2 Ch.4 Sec.4 are fulfilled. Acceptance of other linings necessary to protect the structural material will be specially considered. 2.1.3 Requirements for welding procedure tests and production weld tests are given in Sec.5 and Sec.6. 2.1.4 For certain cargoes as specified in Sec.15 and the IBC code chapter 15, special requirements for materials apply.

2.2 Materials for cargo tanks Materials for integral tanks and independent tanks type a3 may generally be selected in accordance with ordinary practice as given in Pt.3 Ch.3 Sec.1 for hull materials. Materials for independent tanks type a4 (pressure tanks) shall be pressure vessel steel in accordance with Pt.2 Ch.2 Sec.3.

2.3 Materials for cargo piping 2.3.1 Steel is the normal material of construction for cargo pipes. Other materials may be accepted for nonflammable chemicals. Grey cast-iron is not accepted as material of construction in cargo piping on ships with class notation Tanker for chemicals. 2.3.2 Bodies of valves and fittings, and pump housings shall be of cast steel, nodular cast iron grade VL NCI-1 or VL NCI-2 or other approved material (see Pt.2 Ch.2 Sec.9). 2.3.3 Pipes shall be tested according to relevant parts of Pt.2 Ch.2 Sec.5. 2.3.4 Piping for liquid cargo and cargo vapour for tanks made of or protected by corrosion-resistant material shall be made of or protected by a similar material. Guidance note: For cargo piping made of stainless steel, the material should be in accordance with a recognised standard. It is however recommended that the cargo piping is specified with a minimum content of molybdenum of 2.5%. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3.5 Manifold valves and distance pieces or reducers outboard of valves, which are connected directly to the cargo pipeline's shore connection on deck, shall be made of steel and fitted with flanges conforming to ASME B16.5, i.e. shall be of flanged or fully-lugged type.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 26

Part 5 Chapter 6 Section 2

SECTION 2 HULL

3.1 Independent tanks 3.1.1 Scantlings of independent tanks, constructed mainly of plane surfaces, shall be in accordance with relevant requirements given in Pt.3. 3.1.2 Tanks of pressure vessel configuration type (cylinders, spheres etc.) shall be in accordance with the requirements given in Ch.7 Sec.20.

3.2 Emergency towing Emergency towing arrangements for chemical carriers of 20 000 dwt and above shall comply with requirements in Ch.5 Sec.2 [2.2].

3.3 Vertically corrugated bulkhead without stool See Ch.5 Sec.2 [2.1].

3.4 Small confined spaces within or adjacent to cargo tanks 3.4.1 Due to hazards related to reactivity of cargo, small confined spaces within or adjacent to cargo tanks are not acceptable. Railings, ladders and similar fittings within cargo tanks shall be of solid type; hollow profiles are not acceptable. 3.4.2 A doubler plate within the cargo tank is in general not acceptable. If installed, this will be subject to case by case approval.

4 Fatigue assessment See Ch.5 Sec.2 [3].

5 Direct strength calculations See Ch.5 Sec.2 [4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 27

Part 5 Chapter 6 Section 2

3 Strength

1 Cargo tank location 1.1 General 1.1.1 Tanks intended for carriage of cargoes for which Ship type 1 is required, shall be located at a minimum distance from the ship's side shell plating of B/5 or 11.5 m, whichever is less, measured inboard from the ship's side at right angle to the centre line at the level of the summer load line, and at a vertical distance from the moulded line of the bottom shell plating at centre line not less than B/15 or 6 m, whichever is less but not less than 760 mm from the shell plating. 1.1.2 Tanks intended for carriage of cargoes for which Ship type 2 is required, shall be located at a vertical distance from the moulded line of the bottom shell plating at centreline of B/15 or 6 m, whichever is less, but not less than 760 mm from the shell plating. 1.1.3 For Ship type 3, there are no restrictions in respect of cargo tank location. 1.1.4 Except for Ship type 1, suction wells in cargo tanks may protrude into the double bottom below the boundary line defined by the distance given in [1.1.2], provided that such wells are as small as practicable and the protrusion below the inner bottom plating does not exceed 25% of the depth of the double bottom or 350 mm, whichever is less. Where there is no double bottom, the protrusion of the suction well of independent tanks below the upper limit of bottom damage shall not exceed 350 mm.

2 Location and separation of spaces 2.1 General 2.1.1 A cofferdam shall be provided at aft end of cargo area. For spaces which may be approved as cofferdams, see [5.1]. 2.1.2 Fuel oil tanks shall not be situated within the cargo tank block and are not permitted to extend into protective area of cargo tanks required by [3]. Such tanks may, however, be situated at forward and aft end of cargo area instead of cofferdams. Ships which do not have bunker tanks arranged adjacent to cargo tanks, will get the letter k added to the series of letters and numbers given in the register of vessels classed with the Society. 2.1.3 Machinery spaces of category A and boiler spaces shall be positioned aft of the cargo area, but not necessarily aft of fuel oil tanks. Where deemed necessary, machinery spaces other than those of category A may be permitted forward of the cargo area. Machinery spaces shall not be located fully nor partly within the cargo area including within e.g. pumprooms or other spaces approved as cofferdams, except as specified in [2.1.3]. Machinery spaces other than those of category A that contain electrically driven equipment and systems required for cargo handling may upon special considerations be accepted located within the cargo area. Area classification requirements apply. Examples of such systems are: — hydraulic power units for cargo systems — nitrogen generators — dehumidification plants.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 28

Part 5 Chapter 6 Section 3

SECTION 3 SHIP ARRANGEMENTS

2.1.5 Accommodation spaces and service spaces shall be positioned outside the cargo area, but not necessarily aft of fuel oil tanks. Accommodation spaces shall not be situated adjacent to fuel oil bunker tanks adjacent to cargo tanks. 2.1.6 Spaces mentioned in [2.1.3], except machinery spaces of category A, may be positioned forward of the cargo area after consideration in each case. Guidance note: Machinery spaces other than those of category A may be accepted located in forecastle spaces above forepeak tanks even if said forepeak tank is located adjacent to cargo tank. Bow thruster spaces cannot be located adjacent to cargo tanks (see SOLAS Ch.II-2 Reg.4.5.1.3). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.7 Where the fitting of a navigation position above the cargo area is proven necessary, it shall be for navigation purposes only, and it shall be separated from the cargo tank deck by means of an open space with a height of at least 2 m. 2.1.8 Deck spills shall be kept away from accommodation and service areas and from discharge into the sea by a permanent continuous coaming of minimum 100 mm high surrounding the cargo deck. In the aft corners of the cargo deck the coaming shall be at least 300 mm high and extend at least 4.5 m forward from each corner and inboard from side to side. Scupper plugs of mechanical type are required. Means of draining or removing oil or oily water within the coamings shall be provided. 2.1.9 Paint lockers shall not be located within the cargo area.

3 Arrangement of entrances and other openings 3.1 Accommodation and non-hazardous spaces 3.1.1 Entrances, air inlets and openings to accommodation spaces, service spaces, control stations and machinery spaces shall not face the cargo area. They shall be located on the end bulkhead and/or on the outboard side of the superstructure or deckhouse at a distance of at least L/25 but not less than 3 m from the end of the superstructure or deckhouse facing the cargo area. This distance, however, may be below 5 m. Within the limits specified above, the following apply: a) b) c) d)

Bolted plates for removal of machinery may be fitted. Such plates shall be insulated to A-60 class standard. Signboards giving instruction that the plates shall be kept closed unless the ship is gas-free, shall be posted on board. Wheelhouse windows may be non-fixed and wheelhouse doors may be located within the limits, as long as they are so designed that a rapid and efficient gas and vapour tightening of the wheelhouse can be ensured. Windows and sidescuttles shall be of the fixed (non-opening) type. Such windows and sidescuttles except wheelhouse windows, shall be constructed to A-60 class standard. Sidescuttles according to c), in the first tier on the main deck shall be fitted with inside covers of steel or equivalent material.

3.1.2 Cargo control rooms, stores and other spaces not covered by [3.1.3] but located within accommodation, service and control stations spaces, may be permitted to have doors facing the cargo area.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 29

Part 5 Chapter 6 Section 3

2.1.4 The lower portion of the cargo pump room may be recessed into machinery and boiler spaces to accommodate pumps, provided the deck head of the recess is in general not more than one-third of the moulded depth above the keel. For ships of not more than 25 000 tons deadweight, where it is demonstrated that for reasons of access and satisfactory piping arrangements this is impracticable, a recess in excess of such height may be permitted, though not exceeding one half of the moulded depth above the keel.

3.1.3 For access and openings to non-hazardous spaces other than accommodation and service spaces, the following provisions apply: a) b)

entrances shall not be arranged from hazardous spaces entrances from hazardous areas on the open deck shall normally not be arranged. If air locks are arranged such entrances may, however, be approved. See [3.1.5] and [3.1.6].

3.1.4 Ventilation inlets for the spaces mentioned in [3.1.1] shall be located as far as practicable from gasdangerous zones. Ventilation inlets/outlets shall not be located closer to the cargo area than specified for openings in [3.1.1]. 3.1.5 Entrance through air locks to non-hazardous spaces shall be arranged at a horizontal distance of at least 3 m from any opening to a hazardous space containing gas sources, such as valves, hose connection or pumps used with the cargo. 3.1.6 Air locks shall comply with the following requirements: — Air locks shall be enclosed by gastight steel bulkheads with two substantially gas tight self-closing doors spaced at least 1.5 m and not more than 2.5 m apart. The door sill height shall comply with requirements given in Pt.3 Ch.3 Sec.7, but shall not be less than 300 mm. — Air locks shall have a simple geometrical form. They shall provide free and easy passage, and shall have 2 a deck area not less than 1.5 m . Air locks shall not be used for other purposes, for instance as store rooms. — An alarm (acoustic and visual) shall be released on both sides of the air lock to indicate if more than one door has been moved from the closed position. — For requirements for ventilation of air locks, see Sec.10.

3.2 Hazardous spaces and cargo tanks 3.2.1 Pump room entrances shall be from open deck. 3.2.2 Doors to hazardous spaces, situated completely upon the open deck, shall have as low a sill height as possible. 3.2.3 For cargo tanks, no hatches, openings for ventilation, ullage plugs or inspection openings shall be arranged in enclosed compartments.

3.3 Access to and within cargo tanks, void spaces and other spaces in the cargo area 3.3.1 Arrangements for void spaces, cargo tanks and other spaces in the cargo area shall be such as to ensure adequate access for complete inspection. 3.3.2 Access to cofferdams, ballast tanks, cargo tanks and other spaces in the cargo area shall be directly from the open deck. Access to double bottom spaces may be through a cargo pump room, pump room, deep cofferdam, pipe tunnel or similar compartments, subject to consideration of ventilation aspects. 3.3.3 For access through horizontal openings, hatches or manholes, the dimensions shall be sufficient to allow a person wearing a breathing apparatus to ascend or descend without obstruction and also to provide a clear opening to facilitate the hoisting of an injured person from the bottom of the space. The minimum clear opening shall be not less than 600 mm × 600 mm.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 30

Part 5 Chapter 6 Section 3

Where such doors are fitted, the spaces shall not have access to the spaces covered by [3.1.3] and the boundaries of the spaces shall be insulated to A-60 class.

3.3.5 Smaller dimensions than specified in [3.3.3] and [3.3.4] may be approved in special circumstances.

4 Protection of crew 4.1 Arrangement 4.1.1 Guard rails, bulwarks and arrangements for safe access to the bow shall be arranged in accordance with Pt.3 Ch.11 Sec.3 [3]. Open guard rails shall normally be fitted on tank deck. Plate bulwarks, with a 230 mm high continuous opening at lower edge, may be accepted upon consideration of the deck arrangement and probable gas accumulation. Permanently constructed gangways for safe access to the bow should be of substantial strength and be constructed of fire resistant and non-slip material. 4.1.2 Systems with a surface temperature above 60°C shall be provided with insulation or mechanical shielding if they are so located that crew may come in contact with them during normal operation or access.

5 Cargo pump rooms, cofferdams, pipe tunnels and deck trunks 5.1 General 5.1.1 When the ship is certified for carriage of corrosive cargoes, the pump room tank top arrangements shall be installed to deal with possible leakage from cargo pumps and valves in the pump room. 5.1.2 Floors or decks under pumps and pipe connections for acid shall have a lining or coating of corrosionresistant material extending up to a minimum height of 500 mm on the bounding bulkheads or coamings. Hatches or other openings in such floors or decks shall be raised to a minimum height of 500 mm. 5.1.3 Cofferdams shall be of sufficient size for easy access to all parts. Minimum requirements for distance between bulkheads shall be in accordance with [3.3], however not less than 600 mm. 5.1.4 Pump rooms and ballast tanks are accepted as cofferdams. See also [3.1.2]. 5.1.5 Spaces surrounding independent tanks, are normally accepted as cofferdams. 5.1.6 Pipe tunnels shall have ample space for inspection of the pipes, and the pipes shall be situated as high as possible above the ship's bottom. 5.1.7 On ships with integral tanks, no connection between a pipe tunnel and the engine room, either by pipes or manholes, will be accepted. 5.1.8 Deck trunks containing liquid cargo and cargo vapour piping systems shall comply with IMO MSC/ Circ.1276. Deck trunks containing cargo pumps and/or cargo valves shall comply with the requirements for cargo pump rooms. The following shall be provided: — A fixed fire detection and extinguishing system (CO2 is acceptable). Note that the deck trunk area may be excluded from the total area used in the deck foam calculations. — A fixed gas detection in accordance with Ch.5 Sec.9 [6].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 31

Part 5 Chapter 6 Section 3

3.3.4 For access through vertical openings, or manholes providing passage through the length and breadth of the space, the minimum clear opening shall be not less than 600 mm × 800 mm at a height of not more than 600 mm from the bottom shell plating unless gratings or other footholds are provided.

6 Diesel engines driving emergency fire pumps, etc. 6.1 General 6.1.1 Diesel engines driving emergency fire pumps etc. shall be installed in a non-hazardous area. 6.1.2 The exhaust pipe of the diesel engine shall have an effective spark arrester and shall be led out to the atmosphere at a safe distance from hazardous areas.

7 Chain locker and windlass The chain locker shall be arranged as a non-hazardous space. Windlass and chain pipes shall be situated in a non-hazardous area.

8 Anodes, washing machines and other fittings in tanks and cofferdams Anodes, washing machines and other permanently attached equipment units in tanks and cofferdams shall be securely fastened to the structure. The units and their supports shall be able to withstand sloshing in the tanks and vibratory loads as well as other loads which may be imposed in service. Guidance note: When selecting construction materials in permanently attached equipment units in tanks and cofferdams, due consideration ought to be given to the contact spark-producing properties. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9 Slop tanks 9.1 Arrangement 9.1.1 One or more slop tanks for storage of contaminated bilge water from cargo area and tank washings shall be provided. 9.1.2 Means shall be provided to transfer contaminated water to on-shore slop tanks. 9.1.3 Cargo tanks may be accepted as slop tanks. Guidance note: For ships also carrying oil as cargo, see Ch.5 Sec.3 [3.3]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 32

Part 5 Chapter 6 Section 3

— A fixed mechanical ventilation system with capacity of minimum 30 air-changes per hour in accordance with Sec.10. Interlock shall be arranged between ventilation and light. — A fixed bilge system, operable from outside the trunk. — Bilge level alarms shall be in accordance with Sec.13 [2.4].

10.1 General Samples, which shall be kept on board, should be stowed in a designated space situated in the cargo area or, exceptionally, elsewhere subject to special approval.

10.2 Arrangement 10.2.1 The stowage space shall be: a) b)

cell-divided in order to avoid shifting of the bottles at sea made of material fully resistant to the different liquids intended stowed Guidance note: This may be achieved by placing the bottles in leak tight boxes of resistant material, or arranging a spill containment tray of resistant material in the bottom of the locker. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

c)

equipped with adequate ventilation arrangements.

10.2.2 Samples, which react with each other dangerously, shall not be stowed close to each other. 10.2.3 Samples shall not be retained on board longer than necessary.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 33

Part 5 Chapter 6 Section 3

10 Stowage of cargo samples

1 General 1.1 Distance between tanks and hull 1.1.1 The distance between independent tanks and the distance between such tanks and parts of the hull shall be sufficient to give reasonable space for inspection and maintenance. Guidance note: The free distance between independent tanks and the inner edge of ordinary frames should not be less than 500 mm. The free space between tanks and web frames should be not less than 50 mm. The free distance between independent tanks and the inner bottom should generally be not less than 400 mm. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.2 The distance between the ship's shell and an independent tank shall not be less than 760 mm. 1.1.3 The vertical distance between independent tanks and the outer bottom shall not be less than B/15. Drainage sumps will be considered in each case.

2 Gas pressure relief devices 2.1 Pressure and vacuum relief valves 2.1.1 If spaces for independent tanks can be completely closed, these spaces shall be equipped with pressure and vacuum relief valves. The number and size of these valves shall be decided depending on size and shape of the spaces. 2.1.2 The valves are normally to open at a pressure of 0.15 bar above and below atmospheric pressure.

3 Sealing around tanks Efficient sealing shall be provided where independent tanks extend above the upper deck. The sealing material shall be such that it will not deteriorate, even with considerable movement between the tanks and the deck. The sealing shall be able to withstand all temperatures and environmental hazards which may be expected.

4 Earth connections At least two effective earth connections between each tank and the hull shall be arranged.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 34

Part 5 Chapter 6 Section 4

SECTION 4 ARRANGEMENT IN HOLD SPACES

1 Requirements for testing of welds and non-destructive testing 1.1 General 1.1.1 Non-destructive testing of tank shell welds for chemical tankers with Ship type 1 and Ship type 2 notations shall be carried out as given in Table 1. For chemical tankers with Ship type 3 notation, nondestructive testing shall be as for oil carriers. 1.1.2 Most of the testing shall be placed at weld crossings and highly stressed connections. The Society may approve ultrasonic testing in lieu of or in addition to radiographic testing. Where such ultrasonic testing is carried out, the Society may require supplementary radiographic testing. Further, the Society may require ultrasonic testing in addition to radiographic testing. For surface crack detection, magnetic particle testing shall be used for ferromagnetic materials and penetrant testing shall be used for non-ferromagnetic materials. The quality of welds in steel shall comply with ISO 5817 quality level B. 1.1.3 Welding procedure tests are required for independent tanks.

1.2 Weld production tests 1.2.1 Weld production tests are required for independent tanks type a4 (pressure tanks) and independent tanks a3 (atmospheric), if of pressure vessel configuration i.e. cylindrical, spherical. 1.2.2 The requirements for weld production testing are as given for independent cargo tanks type C in Ch.7 Sec.4 [5.3] Table 1 Non-destructive testing of tank welds Tank type

Non-destructive testing 1),4)

Integral tanks

Independent tank

2)

butt welds minimum extent of radiographic testing, % of total weld length

welds other than butt welds. Surface crack detection, % of total weld length

a1

1%

3)

a2

2%

3)

a3

20%

10%, nozzles: 100%

a4

longitudinal welds: 100% transverse welds: 10%

10%, nozzles: 100%

1)

Butt welds of face plates and web plates of girders, stiffening rings etc. shall be radiographically tested as considered necessary.

2)

Guidance: Where double continuous fillet weld is used, full penetration weld at some points is recommended in order to reduce the possibility of leakage along the root of the fillet weld.

3)

The extent of surface crack detection will be decided on the basis of the visual inspection of the boundary welds. Normally this will be 2% to 5% of the total weld length.

4)

Ultrasonic testing may supplement or substitute radiographic testing in accordance with [1.1.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 35

Part 5 Chapter 6 Section 5

SECTION 5 TESTING OF CARGO TANKS

1 Piping systems not used for cargo 1.1 General 1.1.1 There shall be no connection between the piping systems serving the cargo area and the systems in the remainder of the ship except as specially permitted by this section. Guidance note: Piping systems for e.g. hydraulic oil, bunker lines, compressed air, steam and condensate, fire and foam located in the cargo area are generally permitted connected to systems in the remainder of the ship, provided they are not permanently connected to cargo handling systems or have open ends in the cargo tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.2 Piping systems such as compressed air and hydraulic oil which serve systems within tanks or spaces that are not used for cargo, shall not be led through cargo tanks. 1.1.3 Piping systems such as hydraulic oil serving systems within cargo tanks, shall be led to tanks from deck level and shall not penetrate boundaries between cargo tanks and tanks and compartments that do not contain cargo. 1.1.4 In general all piping led from machinery spaces into the cargo area shall be provided with means to preserve the integrity of the machinery space bulkhead. 1.1.5 Piping system with an open end in machinery spaces or in hazardous spaces in the cargo area and piping led from machinery spaces to the cargo area, shall be led above main deck. This also applies to ballast water treatment system piping (see IACS UR M74). Guidance note: For closed piping system without open ends, pipe penetrations may be accepted in the ER bulkhead if readily accessible isolation valves are provided in the machinery space close to the bulkhead. The penetrations shall be located as high as possible. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.6 Pipe penetrations shall be as per Pt.4 Ch.6 Sec.3 [1.4] and type approved according to DNVGLCP-0165. 1.1.7 The temperature in heating systems in the cargo area shall not exceed the temperature determined by the required temperature class of the equipment, as specified for the cargoes carried or 220°C, whichever is less. 1.1.8 Hazardous spaces (including any compartment or tank, cofferdams or void) within the cargo area shall only be drained by bilge pumps or ejectors located within the space itself or within a space with an equivalent hazard. 1.1.9 Pipe tunnels shall be drained from the cargo pump room or an equivalent hazardous space. 1.1.10 Ballast piping and other piping such as sounding and vent piping to ballast tanks shall not pass through cargo tanks. 1.1.11 Filling of tanks within cargo area shall be carried out from the cargo pump room or a similar hazardous space.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 36

Part 5 Chapter 6 Section 6

SECTION 6 PIPING SYSTEMS IN THE CARGO AREA

Guidance note: The requirement is not intended as prohibition to use additional portable washing machines through necessary access openings to enable additional complete washing of cargo tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Cargo pump rooms 1.2.1 Two possibilities for drainage shall be provided, one of which shall be operable from open deck. One ejector with two sources of supply will be accepted. 1.2.2 Bilge pump or ejector independent of the cargo pumps shall be fitted for drainage of the cargo pump rooms. 1.2.3 The bilge pipes in a cargo pump room shall not be led into the engine room.

1.3 Cofferdams and pipe tunnels 1.3.1 Cofferdams and pipe tunnels shall be provided with sounding pipes and with air pipes led to the atmosphere. For ships carrying flammable cargoes, the air pipes shall be fitted with flame screens at their outlets. 1.3.2 Cofferdams, pipe tunnels, voids and other dry compartments below main deck and within the cargo area, shall be provided with permanent means for bilge drainage. Guidance note: For voids, located at main deck level with direct access from open deck (e.g. transverse upper stool spaces), portable draining arrangements may be accepted. Arrangements where the use of the portable drainage equipment requires entry into the void will not be accepted. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.4 Spaces for independent tanks 1.4.1 Spaces for independent tanks shall be connected to a bilge system. 1.4.2 The capacity shall normally be such that the requirements given in Pt.4 Ch.6 Sec.4 are complied with. However, these requirements may be reduced by 50%, when the volume of the tanks is more than 75% of the total volume of the space. 1.4.3 Cargo pumps may be accepted for bilge system purposes to spaces for independent tanks when the pumps are so arranged that they effectively can be used for this purpose. The necessary pipe connection between cargo pumps and the space around the tanks shall not penetrate any part of tank walls situated in closed spaces or lower than the liquid level to maximum filling of the tank. Pipe connections shall be so arranged that cargo cannot be pumped into the spaces due to incorrect operation of valves etc.

1.5 Ballast systems 1.5.1 Filling or discharge of tanks within the cargo area with ballast shall be carried out from the cargo pump room, a similar hazardous space or from inside ballast tanks, except as permitted by [1.5.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 37

Part 5 Chapter 6 Section 6

1.1.12 On tankers, where inerting of cargo tanks is mandatory, tank cleaning machines shall be permanently installed.

1.5.3 Filling of ballast in cargo tanks may be arranged from deck level by pumps serving permanent ballast tanks, provided that the filling line has no permanent connection to cargo tanks or piping and that non-return valves are fitted. 1.5.4 Filling lines to permanent ballast tanks shall be so arranged that the formation of static electricity is reduced, e.g. by reducing the free fall into the tank to a minimum. 1.5.5 Suction for seawater to permanent ballast tanks shall not be arranged in the same sea chest as used for discharge of ballast water from cargo tanks, see also [2.3.5]. Guidance note: Seawater suction should be arranged at the opposite side from the discharge of ballast water from cargo tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.5.6 Lines from the engine room to ballast tanks forward of the cargo area shall be carried outside cargo tanks. 1.5.7 For requirements for drainage of ballast tanks, see Pt.4 Ch.6 Sec.4 [9]. 1.5.8 Ballast water treatment systems shall comply with safety requirements of Pt.6 Ch.7 Sec.1.

1.6 Forepeak ballast tank The forepeak may be ballasted with the system serving ballast tanks within the cargo area, provided that: a) b) c) d)

The forepeak tank is considered as hazardous. The air pipes shall be located on open deck. The hazardous zone classification in way of the air pipe shall be in accordance with Sec.12. Means are provided, on the open deck, to allow measurement of flammable gas concentrations within the tank by a suitable portable instrument. The access to the forepeak and the sounding arrangements are directly from open deck. In case the forepeak tank is separated by cofferdams from the cargo tanks, an access via upper void having direct access to open deck or through a gas tight bolted manhole located in an enclosed space, may be accepted. In that case, a warning sign shall be provided at the manhole, stating that the tank may only be opened either after the tank has been proven to be gas free or after the electrical equipment that is not certified safe in the enclosed space, is isolated.

1.7 Fuel oil tanks Fuel oil bunker tanks situated at forward or aft end of the cargo area may be connected directly to pumps in the engine room. The pipes shall not pass through cargo tanks.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 38

Part 5 Chapter 6 Section 6

1.5.2 Pumps, ballast lines, vent lines and other similar equipment serving permanent ballast tanks shall be independent of similar equipment serving cargo tanks and from cargo tanks themselves. Discharge arrangements for permanent ballast tanks sited immediately adjacent to cargo tanks, should be outside engine room and accommodation spaces. Filling arrangements may be located in the engine room, provided that such arrangements ensure filling from tank deck level and provided that non-return valves are fitted.

2.1 General 2.1.1 The complete system of piping and pumps shall be provided for the cargo tanks and positioned within the cargo area, except for bow and stern loading systems complying with [5]. This system shall be entirely separate from all other piping systems on board. Steam and water systems shall be connected to the cargo piping only by non-permanent means, and be fitted with a non-return valve in the cargo area upstream of the first outlet branch. See Sec.9 regarding pipes for ventilation or inerting purposes. 2.1.2 The cargo piping system shall be dimensioned according to Pt.4 Ch.6 Sec.8. The design pressure p is the maximum working pressure to which the system may be subjected. Due consideration shall be given to possible liquid hammering in connection with the closing of valves. The design pressure for cargo piping shall be 10 bar as a minimum. For ships designed for the carriage of high density cargo, including partially loaded tanks, the design pressure shall take into account the density of such cargo. Guidance note: Maximum pressure will occur with the cargo pump running at full speed against closed manifold valve. As an alternative to increased design pressure when carrying high density cargo, a pressure monitoring system which automatically prevents the design pressure from being exceeded, may be accepted. The system shall activate an alarm at the cargo control station. The system shall not impair the operation of ballast and bilge pumps connected to the cargo pump power supply system. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.3 The cargo piping shall be joined by butt welding with a minimum of flange connections. Where flanges are used, they shall comply with the following: — Flange types A and B will be accepted in piping systems with design pressure p > 16 bar. See Pt.4 Ch.6 Sec.9 Figure 5. — Flange types A, B and C will be accepted in piping systems with design pressure p ≤ 16 bar. — Flange connections in piping systems constructed of materials other than mild steel, will be especially considered. 2.1.4 All cargo piping shall be electrically bonded to the ship's hull. The resistance to earth from any point in 6 the piping system shall not exceed 10 Ohm. Fix points may be considered as an effective bonding. Piping sections not permanently connected to the hull, shall be electrically bonded to the hull by bonding straps. 2.1.5 Regarding manifold valves, distance pieces and reducers, see Sec.2 [2.3.5].

2.2 Cargo pumps 2.2.1 At least two independently driven cargo pumps shall be connected to the system. 2.2.2 In tankers where cargo tanks are equipped with independent pumps (e.g. deep well pumps), the installation of one pump per tank may be approved. Satisfactory facilities shall be provided for emptying the tanks in case of failure of the regular pump.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 39

Part 5 Chapter 6 Section 6

2 Cargo piping system

2.2.4 Cargo pumps shall be certified as required by Pt.4 Ch.6 Sec.1 Table 4. For electrically driven pumps, associated electric motors and motor starters shall be certified as required by Pt.4 Ch.8 Sec.1 Table 3. For steam driven pumps, steam turbines shall be certified in accordance with Pt.4 Ch.6. For hydraulically driven pumps, hydraulic pumps shall be certified in accordance with Pt.4 Ch.6. 2.2.5 Where machinery in the cargo pump room or other hazardous spaces are driven by shafting passing into the pump room through bulkheads or deck plating, gastight glands shall be fitted. The glands shall be efficiently lubricated and shall be constructed so to reduce the risk of overheating. The glands shall be visible and easily accessible. Parts which may accidentally come into contact if the seal is badly aligned or if a bearing is damaged, shall be of such material that no spark will occur. If an expansion below is fitted, it shall be hydraulically pressure tested. 2.2.6 Displacement pumps shall have relief valves with discharge to the suction line. 2.2.7 Means shall be provided for stopping the pumps from an easily accessible position outside the pump room.

2.3 Arrangement and general design 2.3.1 The complete cargo piping system shall be located within the cargo area. Bow or stern loading and discharge arrangements may be accepted by the Society after special consideration. See requirements in Ch.5 Sec.4. 2.3.2 Valves or branch pieces, which connect the cargo pipeline's shore connection on deck, and cargo piping shall be supported with due regard to load stresses. 2.3.3 Expansion elements shall be provided in the cargo piping as necessary. The elements shall not be of the sliding type. 2.3.4 Filling lines to cargo tanks shall be so arranged that the formation of static electricity is reduced, e.g. by reducing the free fall into the tank to a minimum. 2.3.5 The discharge of ballast water from cargo tanks shall be arranged in such a way as to prevent the ballast water from being drawn into sea suctions for other pipe systems, e.g. cooling water systems for machinery. 2.3.6 Cargo piping systems shall not be installed under deck between the outboard side of the cargo containment spaces and the skin of the ship, unless clearances required in Sec.1 [2.6] are maintained. This requirement does not apply when damage to the pipe would not cause release of cargo. 2.3.7 Means for drainage of the cargo lines shall be provided. 2.3.8 Runs of cargo piping, located below the weather deck, may run from the tank they serve and penetrate tank bulkheads or boundaries common to adjacent (longitudinally or transversely) cargo tanks, ballast tanks or empty tanks or pump rooms, provided that inside the tank they serve, the runs are fitted with a stop valve operable from the weather deck. As an exception, where a cargo tank is adjacent to a pump room the stop valve operable from the weather deck may be situated on the tank bulkhead on the pump room side, provided an additional valve is fitted between the bulkhead valve and the cargo pump.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 40

Part 5 Chapter 6 Section 6

2.2.3 Hydraulically powered pumps, submerged in cargo tanks (e.g. deep well pumps), shall be arranged with double barriers, preventing the hydraulic system serving the pumps from being directly exposed to the cargo. The double barrier shall be arranged for detection and drainage of possible cargo leakage.

— the valve is not located within the damage area as determined by damage stability requirements — the valve is specifically designed to prevent leakage in way of valves glands into the space where the valve is located — the valve is fitted to the bulkhead to the cargo tank served — the valve is operable from a manned control station on or above weather deck — the space in which the valve is located is provided with means for detection of leakages — the space in question is arranged for containing leakages from the cargoes carried. 2.3.9 Runs of cargo piping installed in pipe tunnels shall comply with the requirements in [2.3.8] and [2.3.11]. The tunnel shall not have any other openings except to the weather deck and the pump room. 2.3.10 Runs of cargo piping through bulkheads shall not utilise flanges bolted through the bulkhead. 2.3.11 In any pump room where a pump serves more than one tank, a stop valve shall be fitted in the line to each tank. 2.3.12 A stop valve shall be fitted at each cargo hose shore connection. 2.3.13 A stop valve capable of being manually operated, shall be fitted on each tank filling and discharge line, located near the tank penetration. If individual deep-well pumps are installed, a stop valve at the tank is not required on the discharge line. 2.3.14 Means for gas-freeing of the cargo lines shall be provided. 2.3.15 The controls necessary during transfer and/or transport of cargoes other than in pump rooms which have been specially dealt with, shall not be located below the weather deck. 2.3.16 In case of pressure type independent cargo tanks, all pipe connections shall be above the liquid level. 2.3.17 Drainage systems from cargo deck, drip trays etc. shall be arranged for transfer to cargo or slop tanks. Connections to cargo and slop tanks shall be arranged for separation by spool pieces or similar and shall be provided with means for prevention of backflow of vapour. 2.3.18 Ships that shall be certified for simultaneous carriage of cargoes, residues of cargoes or mixtures which react in a hazardous manner with other cargoes, residues or mixes onboard, shall have separate cargo tank venting systems as well as separate cargo handling systems which shall not pass through other cargo tanks containing such cargoes, residues or mixes. Means for separation shall be located outside cargo tanks, in open air and shall consist of spool pieces or similar. Guidance note: For information regarding incompatibility of cargoes and mixes, see USCG 46 CFR part 150. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.4 Pressure indication Pump discharge pressure gauges shall be provided outside the pump room.

2.5 Welding procedure tests 2.5.1 Welding procedure tests are required for cargo piping of austenitic stainless steel.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 41

Part 5 Chapter 6 Section 6

Where penetrations occur in other dry compartments such as voids, cofferdams and pipe tunnels, a totally enclosed hydraulically operated valve located outside the cargo tank may however be accepted provided that:

2.5.3 Special welding procedure tests will not be required if previous welding procedure tests for similar material, thicknesses and welding positions are satisfactorily documented. Guidance note: In order to comply with requirements for passing radiographic testing of welding of butt joints on stainless steel pipes, it is strongly recommended that welding is carried out with argon-backing inside piping. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.6 Testing 2.6.1 Cargo piping butt welds shall be subjected to radiographic testing covering at least 10% of the welded connections, when steel pipes are used. This percentage may be increased as found necessary by the Society's surveyor. The quality of the welds in steel shall comply with ISO 5817 quality level B. 2.6.2 Cargo piping shall be hydrostatically tested in the presence of the Society's surveyor to a test pressure = 1.5 × the design pressure. If hydrostatic testing of separate lengths of piping, valves, expansion elements etc. has been carried out prior to the installation on board, a tightness test only is required after completion of the installation onboard. 2.6.3 Cargo pumps and associated pump risers shall be hydrostatically tested to 1.5 times the design pressure, with a minimum of 14 bar. For centrifugal pumps the maximum pressure shall be the maximum pressure head on the head-capacity curve. Displacement pumps shall not have lower design pressure than the relief valve opening pressure. Hydrostatic testing of pump housings on submerged pumps will normally not be required. 2.6.4 Pump capacities shall be checked with the pump running at design condition (rated speed and pressure head, viscosity, etc.). Capacity test may be dispensed with for pumps produced in series when previous satisfactory tests have been carried out on similar pumps. 3

2.6.5 For centrifugal pumps having capacities less than 1 000 m /h, the pump characteristic (head-capacity curve) shall be determined for each type of pump. For centrifugal pumps having capacities equal to or 3 greater than 1 000 m /h, the pump characteristic shall be determined over a suitable range on each side of the design point, for each pump. 2.6.6 Special survey arrangements for testing of pumps may be agreed upon.

3 Stripping of cargo tank and cargo lines 3.1 General 3.1.1 The pumping and piping arrangement shall ensure that the amount of residues in each cargo tank and its associated piping, is not in excess of 75 litres (cargo stripping performance str 0.075). 3.1.2 The verification of the above residue quantity shall be through actual testing with water and in accordance with an approved test procedure. See MARPOL 73/78 Annex II, Appendix 5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 42

Part 5 Chapter 6 Section 6

2.5.2 The requirements are as given in Pt.2 Ch.4 Sec.5 except that Charpy tests are not required for austenitic stainless steel.

4.1 Location of discharge outlet 4.1.1 For discharge of cargo contaminated water, an outlet located below the waterline in vicinity of the turn of the bilge, shall be arranged within the cargo area. 4.1.2 The outlet(s) shall be located such that the cargo contaminated discharges will not enter the ship's seawater intakes.

4.2 Sizing of the discharge outlet The internal diameter of the outlet shall not be less than:

where:

QD L

3

= discharge rate [m /h] = distance of outlet from forward perpendicular [m].

In the case of angled outlets, only the velocity component of the discharge perpendicular to the ship's shell plating shall be considered when determining QD. The discharge rate assumed as the basis for outlet(s) sizing shall not be less than the aggregate throughput of the washing machines in anyone tank.

4.3 Cargo record book and SMPEP 4.3.1 All ships having a certificate of fitness (COF) for the carriage of liquid substances as listed in the IBC code chapter 17 and 18, shall have a cargo record book on board, according to MARPOL 73/78, Annex II Appendix 2. 4.3.2 All ships having a certificate of fitness (COF) for the carriage of liquid substances as listed in the IBC code chapter 17 and 18, shall carry a shipboard marine pollution emergency Plan (SMPEP) on board, according to MARPOL 73/78 Annex II, Reg. 17.

5 Stern loading and unloading arrangements 5.1 General 5.1.1 Subject to the approval of the Society, cargo piping may be fitted to permit stern loading and unloading. Portable arrangements are not permitted. 5.1.2 Stern loading and unloading lines shall not be used for the transfer of products required carried in Ship type 1 ships. Stern loading and unloading lines shall not be used for the transfer of cargoes emitting toxic vapours required to comply with Sec.9 [2.4], unless specifically approved by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 43

Part 5 Chapter 6 Section 6

4 Discharge of contaminated water

In addition to Pt.4 Ch.6 Sec.8, the following provisions apply: a)

b) c) d) e) f) g)

The piping outside the cargo area shall be fitted at least 760 mm inboard on the open deck. Such piping shall be clearly identified and fitted with a shut-off valve at its connection to the cargo piping system within the cargo area. At this location, it shall also be capable of being separated by means of a removable spool piece and blank flanges when not in use. The shore connection shall be fitted with a shut-off valve and a blank flange. The piping shall be full penetration butt welded, and fully radiographed. Flange connections in the piping shall only be permitted within the cargo area and at the shore connection. Spray shields shall be provided at the connections specified in a) as well as collecting trays of sufficient capacity with means for the disposal of drainage. The piping shall be self-draining to the cargo area and preferably into a cargo tank. Alternative arrangements for draining the piping may be accepted by the Society. Arrangements shall be made to allow such piping to get purged after use and maintained gas-safe, when not in use. The vent pipes connected with the purge shall be located in the cargo area. The relevant connections to the piping shall be provided with a shut-off valve and blank flange. If the stern line is used for unloading, the stripping requirements in [3.1] shall be complied with. The stripping requirements shall be verified through a stripping test, using the stern line.

5.3 Accommodation entrances 5.3.1 Entrances, air inlets and openings to accommodation, shall not face the cargo shore connection location of stern loading and unloading arrangements. They shall be located on the outboard side of the superstructure or deckhouse, at a distance of at least 4% of the length of the ship, but not less than 3 m from the end of the house facing the cargo shore connection location of the stern loading and unloading arrangements. This distance, however, may be less than 5 m. Sidescuttles facing the shore connection location and on the sides of the superstructure or deckhouse within the distance mentioned above shall be of the fixed (non-opening) type. In addition, during the use of the stern loading and unloading arrangements, all doors, ports and other openings on the corresponding superstructure or deckhouse side, shall be kept closed. Where, in the case of small ships, compliance with Ch.5 Sec.3 [3.1.1] and this paragraph is not possible, the Society may approve relaxations from the above requirements. 5.3.2 Air pipes and other openings to enclosed spaces not listed in [5.3.1] shall be shielded from any spray which may come from a burst hose or connection. 5.3.3 Escape routes shall not terminate within the coamings required by [5.3.4] or within a distance of 3 m beyond the coamings. 5.3.4 Continuous coamings of suitable height shall be fitted to keep any spills on deck and away from the accommodation and service areas.

5.4 Electrical equipment — fire fighting 5.4.1 Electrical equipment within the coamings required by [5.3.4] or within a distance of 3 m beyond the coamings shall be in accordance with the requirements of Sec.12. 5.4.2 Means of communication between the cargo control station and the cargo shore connection location, shall be provided and certified safe, if necessary. Provision shall be made for the remote shutdown or cargo pumps from the cargo shore connection location.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 44

Part 5 Chapter 6 Section 6

5.2 Piping arrangement

6 Cargo hoses 6.1 General 6.1.1 Liquid and vapour hoses used for cargo transfer shall be compatible with the cargo and suitable for the cargo temperature. 6.1.2 Hoses subject to tank pressure or the discharge pressure of pumps, shall be designed for a bursting pressure not less than 5 times the maximum pressure the hose will be subjected to during cargo transfer. 6.1.3 Each type of cargo hose, complete with end-fittings, shall be prototype-tested, at a normal ambient temperature, with 200 pressure cycles from zero to at least twice the specified maximum working pressure. After this cycle pressure test has been carried out, the prototype test shall demonstrate a bursting pressure of at least 5 times its specified maximum working pressure at the extreme service temperature. Hoses used for prototype testing shall not be used for cargo service. Thereafter, before being placed into service, each new length of cargo hose produced shall be hydrostatically tested at ambient temperature to a pressure not less than 1.5 times its specified maximum working pressure, but not more than two-fifths of its bursting pressure. The hose shall be stencilled or otherwise marked with the date of testing, its specified maximum working pressure and, if used in services other than the ambient temperature services, its maximum and minimum service temperature as applicable. The specified maximum working pressure shall not be less than 10 bar gauge.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 45

Part 5 Chapter 6 Section 6

5.4.3 Ships fitted with stern loading and unloading arrangements, shall be provided with one additional foam monitor, meeting the requirements of Sec.11 [2.2.8] and one additional applicator, meeting the requirements of Sec.11 [2.2.10]. The additional monitor shall be located to protect stern loading and unloading arrangements. The area of the cargo line aft of the cargo area shall be protected by the above mentioned applicator.

1 Cargo heating 1.1 General 1.1.1 The requirements for thermal oil, hot water systems and steam systems given in Pt.4 Ch.6 apply, with additional requirements given in this section. 1.1.2 The heating and cooling media shall be compatible with the cargo. 1.1.3 Heating or cooling systems shall be provided with valves to isolate the system for each tank and to allow manual regulation of flow. 1.1.4 For any heating or cooling system, means shall be provided to ensure that, when in any other but the empty condition, pressure is maintained within the system, higher than the maximum pressure head exerted by the cargo tank content on the system. 1.1.5 Cargo heating and cooling pipes shall not penetrate the cargo tank boundaries other than on the top of the tank. 1.1.6 Means shall be provided for measuring the cargo temperature. When overheating or overcooling could result in a dangerous condition, temperature alarm shall be provided. The means for measuring the cargo temperature shall be of restricted or closed type, respectively, when a restricted or closed gauging device is required for individual substances as shown in the IBC code ch.17 column j. Guidance note: —

A restricted temperature measuring device is subject to the definition for a restricted gauging device in Sec.13 [2.1.1], e.g. a portable thermometer lowered inside a gauge tube of the restricted type.

—

A closed temperature measuring device is subject to the definition for a closed gauging device in Sec.13 [2.1.1], e.g. a remote thermometer of which the sensor is installed in the tank. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.7 Where products with a significant toxic hazard (see IBC code ch.17 column o refers to ch. 15.12, 15.12.1 or 15.12.3) are being heated or cooled, the heating or cooling media shall operate: — in a circuit independent of other ship's services, except for another cargo heating or cooling system, and not enter the engine room, or — in a circuit dependent of other services, if the condensate is not returned to the engine room, or — in a system external to the tanks, or — in a circuit where the medium is sampled to check for the presence of cargo before it is recirculated to other ship's services or into the engine room. The sampling equipment shall be located within the cargo area and be capable of detecting the presence of any toxic cargo being heated or cooled. Guidance note: The suitability of the sampling method shall be documented for each product. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.8 For thermal oil and hot water systems being re-circulated into the engine room, the system shall comply with the following additional requirements: — The system is so arranged that a positive pressure in the heating coil within a cargo tank shall be at least 3 m water column above the static head of the cargo when circulating pump is not in operation. The specific gravity of cargo and the maximum P/V-valve setting shall be taken into account.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 46

Part 5 Chapter 6 Section 7

SECTION 7 CARGO HEATING AND COOLING ARRANGEMENTS

Pressurized expansion tanks may be considered. Expansion tanks shall be fitted with high and low level alarms. Means shall be provided in expansion tanks for detection of flammable cargo vapours. Valves for the individual heating coils shall be provided with locking arrangement to ensure that the coils are under static pressure at all times.

1.1.9 Supply and return pipes for heating coils fitted in cargo tanks shall be arranged for blank flanging outside the engine or boiler room. 1.1.10 Heating coils fitted in tanks intended for carriage of heat sensitive products (see IBC code ch.17 column o refers to ch. 16.6.2) shall be arranged for blank flanging at each tank. 1.1.11 Heating medium temperature shall normally not exceed 220°C. If cargoes with an auto-ignition temperature lower than 220°C are carried, the heating medium temperature shall be adjusted accordingly during transfer of cargo. 1.1.12 Condensate from cargo heating systems shall not be used for feed water for main boilers. 1.1.13 Heating coils shall be tested according to the non-destructive testing requirement listed in Pt.4 Ch.6 Sec.9.

1.2 Heating of cargoes with temperatures above 80°C 1.2.1 Heating plants for cargoes with temperatures above 80°C shall be arranged with redundancy. Redundancy is required for boilers/thermal oil heaters, heat exchangers, heating coils circuits as well as active components (e.g. circulation pumps). Failure of a redundant component shall not reduce the installed heating capacity by more than 50%. 1.2.2 Pumps and valve systems shall be suitable for the type of cargo transported. 1.2.3 Temperature gauges shall be arranged in each cargo tank enabling the monitoring of temperature at bottom, middle and top of tanks. 1.2.4 For cargoes requiring heating above 120°C, cargo pumps, P/V-valves (if fitted), automatic vent heads (if fitted) and cargo lines shall be provided with arrangements for heating.

1.3 Cargo cooling system Any cargo cooling system required to be installed, shall be arranged in accordance with the requirements in Ch.10 Sec.15. In addition, the cooling system shall comply with the requirements given in Pt.4 Ch.6 Sec.6 to the extent these are applicable. Guidance note: Where a cargo cooling system is not required to be installed, only the safety requirements and requirements to environmental protection referred to in rules, should apply. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 47

Part 5 Chapter 6 Section 7

— — — —

1 General 1.1 Marking plates Marking plates shall be made of corrosion resistant material, and shall be permanently fixed to valve handles, flanges or similar parts. Markings, bolt holes, etc. in the tanks themselves shall be avoided. The lettering shall be impressed on the marking plate in letters of at least 5 mm height. The marking plates shall be placed in easily visible positions and shall not be painted.

1.2 Pipelines Pumps, valves and pipelines shall be distinctively marked to identify the service and tanks which they serve. General remarks regarding marking of valves are given in Pt.4 Ch.6 Sec.3.

1.3 Marking of independent tanks Every independent tank shall have a marking plate giving the following information as relevant: — — — — — — —

tank number desgn vapour pressure, in bar 3 maximum cargo density, in t/m 3 capacitym, in m test pressure, in bar name of builder year of costruction.

The marking plate may also be used for the necessary marking of identification. For definitions of: Design vapour pressure po, see Sec.1 [2.9.1]. Test pressure.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 48

Part 5 Chapter 6 Section 8

SECTION 8 MARKING OF TANKS, PIPES AND VALVES

1 Gas freeing of cargo tanks 1.1 General 1.1.1 Means for gas freeing of the tanks shall be provided. The arrangement for gas freeing cargo tanks shall be such to minimize the hazards due to the dispersal of flammable or toxic vapours in the atmosphere and dispersal of flammable or toxic vapour mixtures in a cargo tank. The ventilating system for cargo tanks shall be used exclusively for ventilating purposes. Connection between cargo tank and pump room ventilation will not be accepted. 1.1.2 Gas freeing operations shall be carried out such that vapour is initially discharged in one of the following ways: 1) 2) 3) 4)

through the vent outlets specified in [2.3] or [2.4] through outlets at least 2 m above the cargo tank deck level, with a vertical efflux velocity of at least 30 m/s maintained during the gas freeing operation through outlets at least 2 m above the cargo tank deck level, with a vertical efflux velocity of at least 20 m/s which are protected by suitable devices to prevent the passage of flame for ships required to get inerted when carrying flammable chemicals, before gas-freeing with air, the cargo tanks shall be purged with inert gas through outlets pipes having a cross sectional area such that an exit velocity of at least 20 m/s can be maintained, when any three cargo tanks are being simultaneously supplied with inert gas. This outlet shall be at least 2 meters above deck level. Purging of cargo tanks shall be continued until the concentration of hydrocarbon or other flammable vapours are reduced to less than 2% by volume. Guidance note: When the flammable vapour concentration at the outlets has been reduced to 30% of the lower flammable limit and in the case of a toxic product the vapour concentration does not present a significant health hazard, gas freeing may thereafter be continued at cargo tank deck level. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.3 Permanently installed ventilating and gas-freeing systems with non-permanent connections to cargo tanks or cargo piping, shall comply with the following: — Where the fans are located in a non-hazardous space, the air supply piping from the fan shall have an automatically operated shut-off valve and a non-return valve in series. — The valves shall be located at the bulkhead where the air supply piping leaves the non-hazardous space, with at least the non-return valve on the outside. — The shut-off valve shall open after the fans are started, and close automatically when the fans stop. — Fans shall be of non-sparking type and certified in accordance with Sec.10 [1.2]. 1.1.4 Permanent pipe connections between a ventilating plant or inert gas plant and cargo piping systems will normally not be accepted.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 49

Part 5 Chapter 6 Section 9

SECTION 9 GAS FREEING AND VENTING OF CARGO TANKS

2.1 General 2.1.1 In the following the term pressure relief valve denotes a safety valve which opens at a given internal pressure above atmospheric pressure, and the term vacuum relief valve denotes a safety valve which opens at a given internal pressure below atmospheric pressure. By P/V valves are meant combined pressure/ vacuum relief valves. 2.1.2 The master shall be provided with the maximum permissible loading and unloading rates for each tank or group of tanks consistent with design of the venting systems. 2.1.3 The cargo venting system shall be so designed that, taking into account the density of the cargo vapour mixture, the pressure drop in the cargo tank venting system, due to the gas flow rates corresponding to the maximum design loading and discharge rate, does not exceed the design vapour pressures of the tank. The pressure drop shall include the pressure drop across the P/V-valve and/or other flame arresting elements for the gas flow corresponding to the maximum design loading and discharge rate. As a minimum, any P/V-valve fitted to a cargo tank shall have a capacity for the relief of full flow overpressure of not less than 125% of the gas volume flow corresponding to the maximum design loading rate for each tank. The P/V-valve capacity for the relief of underpressure, shall not be less than the gas flow corresponding to the maximum design discharge rate for each tank. Guidance note: USCG Vapour emission control systems (VECS): Note that for ship intended to comply with USCG regulations, the maximum allowable liquid loading rate when loading with vapour return will be determined by the capacity of the P/V-valves fitted to each tank. Under USCG regulations the P/V-valve capacity 3

shall take into account the vapour growth rate (min. 1.25) and the air vapour density (min. recommended 3.6 kg/m ) of the cargo to get carried. For ships provided with e.g. an in-line P/V-breather valve in connections to common cargo tank venting system or between such a system and the mast riser outlet, the opening pressure of this P/V-breather valve should be taken into account in the pressure drop calculations required by the USCG. However, if the P/V-breather valve can be isolated during vapour return and procedures for same are included in the VECS operation manual, the opening pressure may be disregarded. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.4 Tank venting systems as described in [2.2] - [2.4] below, shall be provided according to IBC code ch.17 column g. 2.1.5 For carriage of IBC code ch.18 products with flash point not exceeding 60°C, tank venting shall at least comply with [2.3]. 2.1.6 Any spool piece or similar means of separation provided in, or connected to a tank venting system, shall be so arranged that mounting or dismantling does not imply exposure to cargo vapour,i.e. isolation valves will normally be required.

2.2 Tank venting system, type c1 (open) 2.2.1 For some particular products, an open tank venting system is applicable. The height of cargo tank vent outlets shall comply with load line requirements, including requirements for automatic vent heads. 2.2.2 The venting system may consist of individual vents from each tank or the vents from each individual tank may be connected to a common header. Due regard shall be paid to requirements for separation of piping systems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 50

Part 5 Chapter 6 Section 9

2 Tank venting systems

2.3 Tank venting system, type c2 (controlled) 2.3.1 The tanks shall have arrangement for pressure/vacuum relief during voyage and venting during loading and unloading with closed tank hatch covers. 2.3.2 Pressure vacuum relief valves shall be fitted to each tank to limit the pressure or vacuum in the tank. The opening pressure of the vacuum relief valves shall normally not be lower than 0.07 bar below atmospheric pressure. The venting system may consist of individual vents from each tank. Alternatively, the vents from each individual tank may be connected on the pressure side of the P/V-valve to a common header. In that case, due regard shall be paid to cargo segregation. 2.3.3 Shut-off valves shall not be fitted neither above nor below P/V valves, unless alternative means of controlled venting are provided to prevent the tank being isolated from atmosphere. 2.3.4 The venting system shall be designed with redundancy for the relief of full flow overpressure and vacuum. One of the following arrangements may be accepted: — Two P/V-valves fitted to each individual cargo tank, without means for isolation, each with a capacity as required by [2.1.5]. — Pressure sensors fitted in each individual cargo tank, and connected to an alarm system. The setting of the over-pressure alarm shall be above the pressure setting of the P/V-valve and the setting of the under-pressure alarm shall be below the vacuum setting of the P/V-valve. The alarm settings shall be within the design pressures of the cargo tanks. The settings shall be fixed and not arranged for blocking or adjustment in operation, unless the ship is approved for carrying P/V-valves with different settings. See Sec.13 regarding high level alarms, overflow systems etc. Guidance note: In case the pressure sensors required are also used for USCG vapour return purposes, then the system shall be provided with multiple fixed settings. E.g. for ships where inerting is not mandatory, the system shall be provided with mode selection so that the vapour return alarms are blocked except when the ship is loading with vapour return. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3.5 P/V valves shall be located on open deck and shall be of a type which allows the functioning of the valve to get easily checked. 2.3.6 P/V valves and automatic vent heads shall be provided with arrangement for heating when carrying cargoes that may cause clogging. 2.3.7 Intake openings of vacuum relief valves shall be located at least 1.5 m above tank deck, and shall be protected against the sea. The arrangement shall comply with the requirements in Pt.3 Ch.12 Sec.2. 2.3.8 Cargo tank vent outlets shall be situated at not less than 6 m above the weather deck or above the fore and aft gangway, if fitted within 4 m of the gangway. The vent height may be reduced to 3 m above the deck or fore and aft gangway as applicable, provided that high velocity vent valves of an approved type with an exit velocity of at least 30 m/s, are fitted.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 51

Part 5 Chapter 6 Section 9

2.2.3 Shut-off valves or other means of isolation shall not be fitted in cargo tank venting lines, unless alternative means are provided to prevent the tank being isolated from atmosphere.

2.3.9 Vapour outlets for tanks intended for cargoes with flashpoint not exceeding 60°C shall be provided with devices tested and approved according to IMO MSC/Circ.677 as amended by MSC/Circ.1009, to prevent the passage of flame into the cargo tanks. Due attention shall be paid in the design of P/V valves, flame screens and vent heads to the possibility of the blockage of these devices by the freezing of cargo vapour or by icing up in adverse weather conditions. Provisions shall be made so that the system and fittings may be inspected, operationally checked, cleaned or renewed as applicable. 2.3.10 P/V-valves, gas freeing covers and other flame arresting elements shall also comply with the requirements for maximum experimental safety gap (MESG) corresponding to the gas group required for each cargo in column i’ of ch.17 of the IBC code (see IMO MSC.1/Circ.1324 amending IMO MSC Circ.677). Guidance note: For ships carrying cargoes requiring gas group IIA, the corresponding MESG is 0.9 mm (oil tanker standard). For ships carrying cargoes requiring gas group IIB, the corresponding MESG is 0.65 mm. For ships carrying cargoes requiring gas group IIC, the corresponding MESG is 0.28 mm. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3.11 The venting system shall be connected to the highest point of each cargo tank. Vent lines shall be self-draining under all normal operating conditions of list and trim. Where it is necessary to drain venting systems above the level of any P/V valve, capped or plugged drain cooks shall be provided. 2.3.12 Provision shall be made to ensure that the liquid head in any tank does not exceed the test head of that tank. Overflow control systems or spill valves, together with gauging devices and tank filling procedures may be accepted for this purpose. Guidance note: Where the means of limiting cargo tank overpressure includes an automatic closing valve, the valve should comply with [2.2]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.4 Tank venting system, type c3 (controlled venting for toxic products) 2.4.1 Type c3 venting is required for products for which IBC code ch.17 column o refers to ch. 15.12 or parts thereof. The requirements of [2.3] apply with the additions given in [2.4.2], [2.4.3] and [2.4.4]. 2.4.2 The opening pressure of the pressure relief valves shall normally be 0.20 bar above atmospheric pressure. The opening pressure of the vacuum relief valves shall normally not be lower than 0.07 bar below atmospheric pressure. 2.4.3 Gas outlets shall normally be at a minimum height of B/3 or 6 m, whichever is greater, above the weather deck, or in the case of a deck tank, above the access gangway, where B = ship's moulded breadth. Further, the outlets shall not be less than 6 m above the fore and aft gangway, if fitted within a horizontal distance of 6 m from the gangway. The vent height may be reduced to 3 m above the deck or fore and aft gangway, as applicable, provided that high velocity vent valves of an approved type, directing the vapour and air mixture upwards in an unimpeded jet with an exit velocity of at least 30 m/s, are fitted. The outlets shall be situated at a horizontal distance of at least 15 m from air intakes, port holes or doors to accommodation and service spaces. For ships with length less than 90 m, smaller distances may be accepted. 2.4.4 Valved pipe connections for returning the expelled gases ashore during loading, shall be provided.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 52

Part 5 Chapter 6 Section 9

The vent exits shall be arranged at a distance of at least 10 m from the nearest air intake or opening to accommodation and service spaces and ignition sources. The vapour discharge shall be directed upwards in the form of unimpeded jets.

1 System requirements 1.1 General 1.1.1 Any ducting used for the ventilation of hazardous spaces shall be separate from that used for the ventilation of non-hazardous spaces. Ventilation systems within the cargo area shall be independent of other ventilation systems. 1.1.2 Air inlets for hazardous enclosed spaces shall be taken from areas which, in the absence of the considered inlet, would be non-hazardous. Air inlets for non-hazardous enclosed spaces shall be taken from non-hazardous areas at least 1.5 m from the boundaries of any hazardous area. Where the inlet duct passes through a more hazardous space, the duct shall have over-pressure relative to this space, unless mechanical integrity and gas-tightness of the duct will ensure that gases will not leak into it. 1.1.3 Air outlets from non-hazardous spaces shall be located outside hazardous areas. 1.1.4 Air outlets from hazardous enclosed spaces shall be located in an open area which, in the absence of the considered outlet, would be of the same or lesser hazard than the ventilated space. 1.1.5 Ventilation ducts for spaces within the cargo area shall not be led through non-hazardous spaces. 1.1.6 Non-hazardous enclosed spaces shall be arranged with ventilation of the overpressure type. Hazardous spaces shall have ventilation with underpressure relative to the adjacent less hazardous spaces. 1.1.7 Starters for fans for ventilation of gas safe spaces within the cargo area shall be located outside this area or on open deck. If electric motors are installed in such spaces, the ventilation capacity shall be great enough to prevent the temperature limits specified in Pt.4 Ch.8, from being exceeded, taking into account the heat generated by the electric motors. 1.1.8 Wire mesh protection screens of not more than 13 mm square mesh shall be fitted in outside openings of ventilation ducts. For ducts where fans are installed, protection screens shall also be fitted inside of the fan to prevent the entrance of objects into the fan housing. 1.1.9 Spare parts for fans shall be carried onboard. Normally one motor and one impeller is required for each type of fan serving spaces in the cargo area. 1.1.10 Ventilation inlets and outlets for spaces in the cargo area that are required to get mechanically ventilated at sea, shall be located so that they are operable in all weather conditions. This implies that they shall be arranged at a height above deck as required in Pt.3 Ch.12 Sec.7, as a ventilator not requiring closing appliances.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 53

Part 5 Chapter 6 Section 10

SECTION 10 MECHANICAL VENTILATION IN THE CARGO AREA OUTSIDE THE CARGO TANKS

Spaces such as cargo pumprooms, ballast pumprooms and ballast water treatment spaces do normally not require continuous ventilation at sea. Spaces such as nitrogen rooms, cargo heater rooms and deck trunks containing cargo piping and cargo heaters may however require continuous ventilation at sea. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Fans serving hazardous spaces 1.2.1 Fans shall be certified as required by Sec.1 Table 6. Associated electric motors and motor starters shall be certified as required by Pt.4 Ch.8 Sec.1 Table 3. Guidance note: It is recommended that fans are certified in accordance with EN13463-1, EN13463-5 and EN14986. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.2 Electric fan motors shall not be installed in ventilation ducts for hazardous spaces. 1.2.3 Fans shall be designed with the least possible risk for spark generation. 1.2.4 Minimum safety clearances between the casing and rotating parts shall be such as to prevent any friction with each other. The radial air gap between the impeller and the casing shall not be less than 0.1 of the diameter of the impeller shaft in way of the bearing, but not less than 2 mm. It may be less than 13 mm. 1.2.5 The parts of the rotating body and of the casing shall be made of materials which are recognised as being spark proof, and they shall have antistatic properties. Furthermore, the installation on board of the ventilation units shall be such as to ensure safe bonding to the hull of the units themselves. Resistance between any point on the surface of the unit and the hull, shall not 6 be greater than 10 Ohm. The following combinations of materials and clearances used in way of the impeller and duct are considered to be non-sparking: — impellers and or housing of non-metallic material, due regard being paid to the elimination of static electricity — impellers and housings of non-ferrous materials — impellers of aluminium alloys or magnesium alloys and a ferrous (including austenitic stainless steel) housing on which a ring of suitable thickness of non-ferrous materials is fitted in way of the impeller, due regard being paid to static electricity, reliability of the arrangement for securing of the ring to the housing and corrosion between ring and housing — impellers and housing of austenitic stainless steel — any combination of ferrous (including austenitic stainless steel) impellers and housing with not less than 13 mm tip design clearance. 1.2.6 Any combination of an aluminium or magnesium alloy fixed or rotating component and a ferrous fixed or rotating component, regardless of tip clearance, is considered a sparking hazard and shall not be used in these places.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 54

Part 5 Chapter 6 Section 10

Guidance note:

2.1 General 2.1.1 The required capacity of the ventilation plant is normally based on the total volume of the room. An increase in required ventilation capacity may be necessary for rooms having a complicated form. 2.1.2 In case of failure of required fixed mechanical ventilation, an audible and visual alarm shall be activated in a permanently manned control station.

2.2 Non-hazardous spaces 2.2.1 Non-hazardous spaces with opening into a hazardous area, shall be arranged with an air lock in accordance with Sec.3 [3.1.5] and Sec.3 [3.1.6]. Ventilation and safety systems shall be arranged in accordance with IEC 60092-502. — Non-hazardous spaces with opening to an hazardous area, shall be arranged as a pressurised space, protected by an air lock. — The air lock shall be provided with a mechanical ventilation system independent of that of the space protected by the air lock. — The air lock shall be maintained at an overpressure relative to the hazardous area it opens into. — Electrical equipment that is located in spaces protected by air locks, that are not of the certified safe type, shall be de-energized in case of loss of overpressure in the pressurized space. Guidance note: Requirements applicable for air lock arrangements are given in IEC 60092-502 [4]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.2 Machinery necessary for maintaining the main functions, as well as safety systems such as the emergency generator and emergency fire pumps, shall not be located in spaces where automatic disconnection of electrical equipment is required. Guidance note: Equipment suitable for operating in a zone 1 is not required to get disconnected. Certified flameproof lighting may have a separate disconnection circuit. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3 Cargo handling spaces 2.3.1 A permanent mechanical ventilation system shall be installed capable of circulating sufficient air to give at least 30 air changes per hour. Extraction from above and below floor plates shall be possible, with the following arrangement of exhaust trunking: — in the pump room bilges just above the transverse floor plates or bottom longitudinals, so that air can flow over the top from adjacent spaces — an emergency intake located 2 m above the pump room lower grating. This emergency intake would be used when the lower intakes are sealed off due to flooding in the bilges. The emergency intake shall have a damper fitted, which can be remotely opened from the exposed main deck in addition to local opening and closing arrangement at the lower grating. For carriage of certain products, increased ventilation rates are required. See Sec.15 [1.11].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 55

Part 5 Chapter 6 Section 10

2 Ventilation arrangement and capacity requirements

2.3.3 The exhaust outlets shall discharge upwards and shall be situated at least 4 m above tank deck and at least 10 m in the horizontal direction from ventilation inlets to the accommodation and other gas safe spaces. 2.3.4 When the space is dependent on ventilation for its area classification, the following requirements apply: 1) 2) 3)

During initial start-up, and after loss of ventilation, the space shall be purged (at least 5 air changes), before connecting electrical installations which are not certified for the area classification in abscence of ventilation. Operation of the ventilation shall be monitored. In the event of failure of ventilation, the following requirements apply: — an audible and visual alarm shall be given at a manned location — immediate action shall be taken to restore ventilation — electrical installations shall be disconnected if ventilation cannot be restored for an extended period.

The disconnection shall be made outside the hazardous areas, and be protected against unauthorised reconnection, e.g. by lockable switches. Guidance note: Intrisically safe equipment suitable for zone 0, is not required to get switched off. Certified flameproof lighting, may have a separate switch-off circuit. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.4 Other hazardous spaces normally entered 2.4.1 Pump rooms and other enclosed spaces below deck not covered by [2.3], where access may be necessary for normal operation and maintenance, shall be provided with a fixed separate mechanical ventilation system giving at least 20 air changes per hour. 2.4.2 Other spaces situated on or above cargo deck level (e.g. cargo handling gear lockers and cargo sample lockers) may be accepted with natural ventilation only.

2.5 Spaces not normally entered 2.5.1 All spaces mentioned in Sec.1 [2.9.1] shall be arranged for gasfreeing. Where necessary, owing to the arrangement of the spaces, necessary ducting shall be permanently installed in order to ensure safe and efficient gasfreeing. 2.5.2 A mechanical ventilation system (permanent or portable) shall be provided, capable of circulating sufficient air to the compartments concerned. Where a permanent ventilation system is not provided, approved means of portable mechanical ventilation shall be provided. For permanent installations, the capacity of 8 air changes per hour shall be provided. For portable systems, the capacity of 16 air changes per hour shall be provided. Fans or blowers shall be clear of personnel access openings, and shall comply with [1.2.5].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 56

Part 5 Chapter 6 Section 10

2.3.2 Ventilation systems for pump rooms, compressor rooms and other cargo handling spaces shall be in operation when pumps or compressors are working. Warning notices to this effect shall be placed in an easily visible position near the control stand.

1 General 1.1 Application 1.1.1 The fire safety measures in SOLAS related to tankers in general will apply depending on flag state authorisation as specified in Ch.5 Sec.7 [1.1]. 1.1.2 Fire safety measures applicable to chemical tankers are specified in [2] and in Sec.6 [5].

2 Fire extinguishing 2.1 Fire extinguishing in cargo area Suitable fire extinguishing equipment for all products carried, shall be provided. Fire extinguishing media considered to be suitable for certain products are indicated in the IBC code ch.17 column l.

2.2 Deck fire extinguishing system in cargo area 2.2.1 All ships with the class notation Tanker for chemicals or Tanker for C for dedicated chemical cargoes, except those engaged solely in the transport of non-flammable products, shall be fitted with a fixed deck foam fire-extinguishing system in accordance with the following requirements. Ships which are dedicated to the carriage of specific cargoes may, however, be protected by alternative provisions to the satisfaction of the Society when they are equally effective for the products concerned as the deck foam system required for the generality of flammable cargoes. Guidance note: The expression ships which are dedicated to the carriage of specific cargoes is understood as ships that are dedicated to the carriage of a restricted number of cargoes. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.2 For ships intended to carry flammable products with flash point exceeding 60°C, the requirements specified for oil tankers in Ch.5 Sec.7 shall be applied in lieu the regulations of this section. 2.2.3 Only one type of foam concentrate shall be supplied, and it shall be effective for the maximum possible number of cargoes intended to be carried. For other cargoes for which foam is not effective or is incompatible, additional arrangements to the satisfaction of the Society shall be provided. Basic protein foams shall not be used. 2.2.4 The arrangements for providing foam shall be capable of delivering foam to the entire cargo tank area as well as into any cargo tank, the deck of which is assumed to be ruptured. 2.2.5 The deck foam system shall be capable of simple and rapid operation. The main control station for the system shall be suitably located outside of the cargo tank area, adjacent to the accommodation spaces and readily accessible and operable in the event of fires in the areas protected. 2.2.6 The rate of supply of foam solution shall be not less than the greater of the following: a) b)

2

2 l/m minute of the cargo deck area, where cargo deck area means the maximum breadth of the ship times the total longitudinal extent of the cargo tank spaces 2 20 l/m minute of the horizontal sectional area of the single tank having the largest such area

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 57

Part 5 Chapter 6 Section 11

SECTION 11 FIRE PROTECTION AND EXTINCTION

2

10 l/m minute of the area protected by the largest monitor, such area being entirely forward of the monitor, but not less than 1 250 l/minute. For ships of less than 4 000 tons deadweight, the minimum capacity of the monitor shall be to the satisfaction of the Society.

2.2.7 The foam concentrate shall be type approved, and delivered with a declaration of conformity and a declaration of the main characteristics (sedimentation, pH-value, expansion ratio, drainage time and volumetric mass and date of production). 2.2.8 Alcohol resistant fluorine protein based foam concentrates are subjected to a chemical stability test with acetone before pouring into foam tank and a new chemical stability test after installation onboard (preferably as long as possible but not less than after 14 days after installation onboard). A surveyor will collect the sample and witness the test. Guidance note: For test programme and requirements see appendix A of Type Approval Program 474.65. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.9 Sufficient foam concentrate shall be supplied to ensure at least 30 minutes of foam generation when using solution rates stipulated in [2.2.6] (a), (b) and (c), whichever is the greatest. 2.2.10 Foam from the fixed foam system shall be supplied by means of monitors and foam applicators. At least 50% of the foam rate required in [2.2.6] (a) or (b) shall be delivered from each monitor. The capacity of any monitor shall be at least 10 l/minute of foam solution per square metre of deck area protected by that monitor, such area being entirely forward of the monitor. Such capacity shall be not less than 1 250 l/ minute. For ships of less than 4 000 tons deadweight, the minimum capacity of the monitor shall be to the satisfaction of the Society. 2.2.11 The distance from the monitor to the farthest extremity of the protected area forward of that monitor shall be not more than 75% of the monitor throw in still air conditions. 2.2.12 A monitor and hose connection for a foam applicator shall be situated both port and starboard at the poop front or accommodation spaces facing the cargo tanks. 2.2.13 Applicators shall be provided for flexibility of action during fire-fighting operations and to cover areas screened from the monitors. The capacity of any applicator shall be not less than 400 l/minute and the applicator throw in still air conditions shall be not less than 15 m. The number of foam applicators provided shall be not less than four. The number and disposition of foam main outlets shall be such that foam from at least two applicators can be directed to any part of the cargo tank deck area. 2.2.14 Valves shall be provided in the foam main, and in the fire main where this is an integral part of the deck foam system, immediately forward of any monitor position to isolate damaged sections of those mains. 2.2.15 Operation of a deck foam system at its required output shall permit the simultaneous use of the minimum required number of jets of water at the required pressure from the fire main. 2.2.16 Suitable portable fire extinguishing equipment for the products carried, shall be provided and kept in good operating order. 2.2.17 All sources of ignition shall be excluded from spaces where flammable vapours may be present, except as permitted in Sec.12. 2.2.18 When the alternative deck fire extinguishing system permitted under [2.2.1] is a fixed dry chemical powder fire extinguishing system, the system shall comply with Ch.5 Sec.11.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 58

Part 5 Chapter 6 Section 11

c)

2.3.1 Ships with the class notation Tanker for chemicals, shall be equipped with a fixed carbon dioxide fire-extinguishing system in the cargo pump room, as specified in [2.3.2] to [2.3.4] below. For ships with class notation Tanker for C for dedicated chemical cargoes, see [2.3.5]. 2.3.2 A cargo pump room carbon dioxide fire extinguishing system shall comply with the requirements in SOLAS Reg. II-2/10.9. 2.3.3 The amount of gas carried shall be sufficient to provide a quantity of free gas equal to 45% of the gross volume of the cargo pump room in all cases. 2.3.4 A notice shall be exhibited at the controls stating that the system in only to be used for fire extinguishing and not inerting purposes, due to the electrostatic ignition hazard. 2.3.5 Cargo pump rooms of ships which are dedicated to the carriage of specific cargoes shall be protected to the satisfaction of the Society. Guidance note: The expression ships which are dedicated to the carriage of specific cargoes is understood as ships that are dedicated to the carriage of a restricted number of cargoes. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3.6 A fire-extinguishing system consisting of either a fixed pressure water spray system or a high expansion foam system, could be provided for the cargo pump room if it can be adequately demonstrated to the Society that cargoes will be carried which are not suited to extinguishment by carbon dioxide. The appendix to classification certificate will reflect this conditional requirement. 2.3.7 Steam smothering systems are not accepted for cargo pump rooms.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 59

Part 5 Chapter 6 Section 11

2.3 Fire extinguishing in cargo pump rooms

1 General 1.1 Application 1.1.1 The requirements in this section are additional to those given in Pt.4 Ch.8 and apply to tankers with the class notations Tanker for chemicals. The requirements may be made wholly or partly valid also for tankers for dedicated chemical cargoes (Tanker for c) in some cases. 1.1.2 Tankers exclusively built to carry cargoes with flash point above 60°C will be considered in each case. See [3.3].

1.2 Insulation monitoring Insulation fault Device(s) intended for continuous monitoring of insulation earth, shall be installed for both insulated and earthed distribution systems. An audible and visual alarm shall be given at a manned position in the event of an abnormally low level of insulation resistance and/or high level of leakage current.

2 Electrical installations in hazardous areas 2.1 General 2.1.1 Electrical equipment and wiring shall in general not be installed in hazardous areas. Where essential for operational purposes, the arrangement of electrical installations in hazardous areas shall comply with Pt.4 Ch.8 Sec.11, based on area classification specified in [3]. In addition, installations specified in [2.1.2] are accepted. Except as specified in [2.1.2] and [3.3], operational procedures are not acceptable as an equivalent method of ensuring compliance with these rules. Guidance note: Note however that for chemical tankers the requirements for gas group and temperature class are specified for each cargo in columns i’ and ii’’ of ch.17 of the IBC code. For advanced stainless steel chemical tankers, selecting equipment complying with requirements for gas group IIB and temperature class T4 should be considered. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Zone 1 2.1.2 Impressed cathodic protection equipment, electric depth-sounding devices and log devices are accepted provided that the following is complied with: — such equipment shall be of gas-tight construction or be housed in a gas tight enclosure — cables shall be installed in steel pipes with gas-tight joints up to the upper deck — corrosion resistant pipes, providing adequate mechanical protection, shall be used in compartments which may be filled with seawater (e.g. permanent ballast tanks) — wall thickness of the pipes shall be as for overflow and sounding pipes through ballast or fuel tanks, in accordance with Pt.4 Ch.6 Sec.6. 2.1.3 Additional requirements may apply for certain cargoes according to IBC code ch.15 and ch.17.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 60

Part 5 Chapter 6 Section 12

SECTION 12 AREA CLASSIFICATION AND ELECTRICAL INSTALLATIONS

3 Area classification 3.1 General 3.1.1 Area classification is a method of analysing and classifying the areas where explosive gas atmospheres may occur. The object of the classification shall allow the selection of electrical apparatus able to be operated safely in these areas. 3.1.2 In order to facilitate the selection of appropriate electrical apparatus and the design of suitable electrical installations, hazardous areas are divided into zones 0, 1 and 2 according to the principles of the standards IEC 60079-10 and IEC 60092-502. Classification of areas and spaces typical for tankers, is given in [3.2] and [3.3], based on IEC 60092-502. 3.1.3 Areas and spaces other than those classified in [3.2] and [3.4], shall be subject to special consideration. The principles of the IEC standards shall be applied. 3.1.4 Area classification of a space may be dependent of ventilation as specified in IEC 60092-502, table 1. Requirements for such ventilation are given in Sec.10 [2.3.4]. 3.1.5 A space with opening to an adjacent hazardous area on open deck, may be made into a less hazardous or non-hazardous space, by means of overpressure. Requirements for such pressurisation are given in Sec.10 [1.2.1] to Sec.10 [1.2.5]. 3.1.6 Ventilation ducts shall have the same area classification as the ventilated space. 3.1.7 With the exception of spaces arranged in accordance with [3.1.5], any space having an opening into a hazardous area or space, having a more severe classification, will be considered to have the same hazardous zone classification as the zone it has an opening into. Guidance note: Openings are considered to be any access door, ventilation inlets or outlets or other boundary openings. Bolted plates that are normally closed and only opened when area has been confirmed gas free may be accepted. Requirements for access and openings to non-hazardous spaces are given in Sec.3 [3.1.3]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2 Tankers for carriage of products with flashpoint not exceeding 60°C. Hazardous areas zone 0 3.2.1 1) 2) 3) 4)

interiors of cargo tanks slop tanks pipework of pressure-relief or other venting systems for cargo and slop tanks pipes and equipment containing the cargo or developing flammable gases or vapours.

3.2.2 Hazardous area zone 1 1) 2) 3)

void spaces and cofferdams adjacent to, above and below integral cargo tanks hold spaces containing independent cargo tanks ballast tanks and any other tank adjacent to cargo tanks

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 61

Part 5 Chapter 6 Section 12

2.1.4 The materials used for electrical equipment shall not react dangerously with the cargo liquids or gases to which they may be exposed, and shall be corrosion resistant against such liquids or gases.

6) 7)

cargo handling spaces (including cargo pump rooms) enclosed or semi-enclosed spaces, immediately above cargo tanks (for example, between decks) or having bulkheads above and in line with cargo tanks bulkheads, unless protected by a diagonal plate acceptable to the appropriate authority spaces, other than cofferdam, adjacent to and below the top of a cargo tanks (for example, trunks, passageways, pumprooms, ballast treatment spaces and hold spaces) areas on open deck, or semi- enclosed spaces on deck, within 3 m of any cargo tank outlet, gas or vapour outlet (see note), cargo manifold valve, cargo valve, cargo pipe flange, cargo pump-room ventilation outlets and cargo tank openings for pressure release provided to permit the flow of small volumes of gas or vapour mixtures caused by thermal variation Guidance note: Such areas are, for example, all areas within 3 m from cargo tank hatches, sight ports, tank cleaning openings, ullage openings, sounding pipes, cargo vapour outlets. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

8)

9) 10) 11) 12) 13)

areas on open deck, or semi-enclosed spaces on open deck above and in the vicinity of any cargo gas outlet, designed for the passage of large volumes of gas or vapour mixture during cargo loading and ballasting or during discharging, within a vertical cylinder of unlimited height and 6 m radius cantered upon the centre of the outlet, and within a hemisphere of 6 m radius below the outlet areas on open deck, or semi-enclosed spaces on deck, within 1.5 m of cargo pump room entrances, cargo pump room ventilation inlet, openings into cofferdams or other zone 1 spaces areas on the open deck within spillage coamings surrounding cargo manifold valves and 3 m beyond these, up to a height of 2.4 m above the deck areas on open deck over all cargo tanks (including ballast tanks within the cargo tank area) where structures are restricting the natural ventilation and to the full breadth of the ship plus 3 m fore and aft of the forward-most and the aft-most cargo tank bulkhead up to a height of 2.4 m compartments for cargo hoses and contaminated cargo equipment Enclosed or semi-enclosed spaces in which pipes containing liquid cargoes or cargo vapour are located.

3.2.3 Hazardous areas zone 2 1) 2) 3) 4) 5)

6)

areas within 1.5 m surrounding open or semi-enclosed spaces of zone 1 as specified in [3.2.2], if not otherwise specified in this standard spaces 4 m beyond the cylinder and 4 m beyond the sphere defined in [3.2.2] 8) the spaces forming an air-lock as defined in Sec.1 [2.9.1] and Ch.5 Sec.3 [4.1.5] and Ch.5 Sec.3 [4.1.6]. areas on open deck extending to the coamings fitted to keep any spills on deck and away from the accommodation and service areas and 3 m beyond these up to a height of 2.4 m above deck areas on open deck over all cargo tanks (including all ballast tanks within the cargo tank area) where unrestricted natural ventilation is guaranteed and to the full breadth of the ship plus 3 m fore and aft of the forward-most and aft-most cargo tank bulkhead, up to a height of 2.4 m above the deck surrounding open or semi-enclosed spaces of zone 1 spaces forward of the open deck areas to which reference is made in [3.2.2] 11) and [3.2.2] 5), below the level of the main deck, and having an opening on to the main deck or at a level less than 0.5 m above the main deck, unless: a) b)

the entrances to such spaces do not face the cargo tank area and, together with all other openings to the spaces, including ventilating system inlets and exhausts, are situated at least 10 m horizontally from any cargo tank outlet or gas or vapour outlet, and the spaces are mechanically ventilated.

7)

forepeak ballast tanks, if connected to a piping system serving ballast tanks within the cargo area. See Sec.6 [1.6]

8)

ballast pump-rooms or ballast treatment spaces which are not located adjacent to cargo tanks, but which could contain contaminated ballast water from ballast tanks located adjacent to cargo tanks.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 62

Part 5 Chapter 6 Section 12

4) 5)

Spaces containing ballast pumps or treatment systems only used for filling of ballast tanks and are provided with means for prevention of backflow are not considered hazardous. See however Pt.6 Ch.7 Sec.1 regarding ballast treatment systems generating explosive gases. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.3 Tankers for carriage of products with flashpoint exceeding 60°C 3.3.1 Unheated cargoes and cargoes heated to a temperature below and not within 15°C of their flashpoint. Hazardous areas zone 2: — — — —

interiors of cargo tanks slop tanks pipework of pressure-relief or other venting systems for cargo and slop tanks pipes and equipment containing the cargo

3.3.2 Cargoes heated above their flashpoint and cargoes heated to a temperature within 15°C of their flashpoint: the requirements of [3.2] are applicable. Guidance note: It is acceptable that an operational limitation is inserted in the appendix to the classification certificate, specifying that the ship is approved on the condition that cargo is not heated to within 15°C of its flashpoint. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.4 Tankers for carriage of products (e.g. acids) reacting with other products/materials to evolve flammable gases Hazardous areas zone 1 3.4.1 Areas as specified in [3.2.1], [3.2.2] 4) and [3.2.2] 12). 3.4.2 Hazardous areas zone 2 1) 2) 3)

areas of 1.5 m surrounding openings of zone 1 spaces as specified in [3.4.1], if not otherwise specified in the rules areas specified in [3.2.2] 1), [3.2.2] 2), [3.2.2] 3), [3.2.2] 5), [3.2.2] 6), [3.2.2] 13) areas as specified in [3.2.2] 7) and [3.2.2] 10) but with the distances of 2.4 m and 3 m reduced to 1.5 m, and areas as specified in [3.2.2] 8) but with the distance of 6 m reduced to 3 m.

4 Inspection and testing 4.1 General 4.1.1 Before the electrical installations in hazardous areas are put into service or considered ready for use, they shall be inspected and tested. All equipment, cables, etc. shall be verified to have been installed in accordance with installations procedures and guidelines issued by the manufacturer of the equipment, cables, etc., and that the installations have been carried out in accordance to Pt.4 Ch.8 Sec.11. 4.1.2 For spaces protected by pressurisation it shall be examined and tested that the purging can be effected. Purge time at minimum flow rate shall be documented. Required shutdowns and/or alarms upon ventilation overpressure falling below prescribed values shall be tested.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 63

Part 5 Chapter 6 Section 12

Guidance note:

4.1.3 For equipment for which safety in hazardous areas depends upon correct operation of protective devices (for example overload protection relays) and or operation of an alarm (for example loss of pressurisation for an Ex(p) control panel) it shall be verified that the devices have correct settings and/or correct operation of alarms. 4.1.4 Where interlocking and shutdown arrangements are required (such as for submerged cargo pumps), they shall be tested. 4.1.5 Intrinsically safe circuits shall be verified to ensure that the equipment and wiring are correctly installed. 4.1.6 Verification of the physical installation shall be documented by the yard. The documentation shall be available for the Society's surveyor at the site.

5 Maintenance 5.1 General 5.1.1 The maintenance manual referred to in Sec.1 [3.1.1], shall be in accordance with the recommendations in IEC 60079-17 and IEC 60092-502 and shall contain necessary information on: — overview of classification of hazardous areas, with information about gas groups and temperature class — records sufficient to enable the certified safe equipment to be maintained in accordance with its type of protection (list and location of equipment, technical information, manufacturer's instructions, spares etc.) — inspection routines with information about detailing level and time intervals between the inspections, acceptance/rejection criteria — register of inspections, with information about date of inspections and name(s) of person(s) who carried out the inspection and maintenance work. 5.1.2 Updated documentation and maintenance manual, shall be kept onboard, with records of date and names of companies and persons who have carried out inspections and maintenance. Inspection and maintenance of installations shall be carried out only by experienced personnel whose training has included instruction on the various types of protection of apparatus and installation practices on board the vessel. Appropriate refresher training shall be given to such personnel on a regular basis.

6 Signboards 6.1 General 6.1.1 Where electric lighting is provided for spaces in hazardous areas, a signboard at least 200 × 300 mm shall be fitted at each entrance to such spaces with text: BEFORE A LIGHTING FITTING IS OPENED ITS SUPPLY CIRCUIT SHALL BE DISCONNECTED Alternatively, a signboard with the same text can be fitted at each individual lighting fitting.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 64

Part 5 Chapter 6 Section 12

For other spaces where area classification depends on mechanical ventilation it shall be tested that ventilation flow rate is sufficient, and that and required ventilation failure alarm operates correctly.

BEFORE THE LIGHTING IS TURNED ON THE VENTILATION SHALL BE IN OPERATION 6.1.3 Where socket-outlets are installed in cargo area or adjacent area, a signboard shall be fitted at each socket-outlet with text: PORTABLE ELECTRICAL EQUIPMENT SUPPLIED BY FLEXIBLE CABLES SHALL NOT BE USED IN AREAS WHERE THERE IS GAS DANGER Alternatively, signboards of size approximately 600 × 400 mm, with letters of height approximately 30 mm, can be fitted at each end of the tank deck. 6.1.4 Where socket-outlets for welding apparatus are installed in areas adjacent cargo area, the socket outlet shall be provided with a signboard with text: WELDING APPARATUS SHALL NOT BE USED UNLESS THE WORKING SPACE AND ADJACENT SPACES ARE GAS-FREE.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 65

Part 5 Chapter 6 Section 12

6.1.2 Where electric lighting is provided in spaces where the ventilation shall be in operation before the electric power is connected, a signboard at least 200 × 300 mm shall be fitted at each entrance, and with a smaller signboard at the switch for each lighting circuit, with text:

1 General requirements 1.1 General 1.1.1 For instrumentation and automation, including computer based control and monitoring, the requirements in this chapter are additional to those given in Pt.4 Ch.9. The control and monitoring systems shall be certified according to the requirement listed in Sec.1 Table 6. 1.1.2 Remote reading systems for cargo temperature and pressure shall not allow the cargo or vapour to reach gas safe spaces. Direct pipe connections will not be accepted. 1.1.3 If the loading and unloading of the ship is performed by means of remotely controlled valves and pumps, all controls and indicators associated with a given cargo tank shall be concentrated in one control position. 1.1.4 Ships arranged with cargo pump room, carrying chemicals with flashpoint not exceeding 60°C, shall comply with the requirements for pump room safety as given in [2.9], Ch.5 Sec.6 [2.3.2], Ch.5 Sec.9 [2.1.2] and Ch.5 Sec.9 [2.1.3].

2 Alarm, indicating and recording systems 2.1 Cargo tank level gauging 2.1.1 By gauging device is meant an arrangement for determining the liquid level of cargo in tanks. Consideration of the hazard and physical properties of each cargo will give the basis for selecting one of the following types: — open, type b1 Method that makes use of an opening in the tank and directly exposes the operator to the cargo or its vapours. Examples of this type are ullage openings and gauge hatches. — restricted, type b2 Device that penetrates the tank and, when in use, permits a limited quantity of cargo vapour or liquid to be expelled to the atmosphere. When not in use, the device is completely closed. Examples of this type are rotary tube, fixed tube, slip tube and sounding pipe. — closed, type b3 Permanently installed device that penetrates the tank, but being part of a closed system that keeps the cargo containment system completely sealed off from the atmosphere. Examples of this type are sight glasses, pressure cells, float-tape systems, electronic or magnetic probe. — indirect, type b4 device that does not penetrate the tank shell or is independent of the tank and that makes use of an indirect measurement for determining the amount of cargo. Examples are weighing of cargo, pipe flow meter. 2.1.2 Each cargo tank shall be provided with at least one liquid level gauging device. Type of gauging devices required for the individual cargoes are shown in the IBC code ch.17 column j. 2.1.3 If a closed gauging device is not mounted directly on the tank, it shall be provided with shut-off valves situated as close as possible to the tank.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 66

Part 5 Chapter 6 Section 13

SECTION 13 INSTRUMENTATION AND AUTOMATION

2.2.1 Arrangements as described below shall be provided according to the IBC code ch.17 column o (references to 15.19.6 corresponds to f1, references to 15.19 corresponds to f2). 2.2.2 Type f1. The cargo tank shall be fitted with a visual and audible high level alarm. This shall be able to be function tested from the outside of the tank and is also to be independent of the level gauging device required in [2.1.2] and the high-high level alarm required in [2.2.3]. 2.2.3 Type f2. In addition to the high level alarm as described in [2.2.2], a high-high level alarm shall be fitted. The high-high level alarm shall be independent of the high level alarm and the level gauging device.

2.3 Vapour detection 2.3.1 Ships carrying toxic and/or flammable cargoes (see IBC code ch.17 column k) shall be equipped with at least two instruments designed and calibrated for testing for the specific vapours in question. If such instruments are not capable of testing for both toxic concentrations and flammable concentrations, then two separate sets of instruments shall be provided. 2.3.2 Vapour detection instruments may be portable or fixed. If a fixed system is installed, at least one portable instrument shall be provided. 2.3.3 In the case of portable instruments being used, provisions shall be made to facilitate easy measurements, and where necessary fitting of guide tubes to enable gas sampling hose to be easily lead to the space to be tested.

2.4 Cargo temperature measurement Means for measuring the cargo temperature shall be provided. Tanks intended for carriage of cargoes requiring cargo level gauging systems type b2, b3 or b4, shall be provided with a temperature measuring system providing a gas segregation equivalent to the gauging systems required.

2.5 Leakage alarms Hold spaces containing independent cargo tanks, cargo pump-rooms, spaces containing cargo piping, as well as pipe tunnels and dry spaces adjacent to cargo tanks that are normally entered (including ballast pumprooms) shall be provided with level alarms for detection of leakage. The alarms shall be audible and visual and shall be activated at a permanently manned control station.

2.6 Computer (PLC) based systems for cargo handling Local control of cargo handling systems independent of computer controlled systems will be required.

2.7 Centralised cargo control Ships having their cargo and ballast systems built and equipped, surveyed and tested in accordance with the requirements in Pt.6 Ch.4 may be given the additional class notation CCO.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 67

Part 5 Chapter 6 Section 13

2.2 Overflow control

2.8.1 The operation of cargo and/or ballast systems may be necessary, under certain emergency circumstances or during the course of navigation, to enhance the safety of tankers. As such, measures shall be taken to prevent cargo and ballast pumps becoming inoperative simultaneously due to a single failure in the integrated cargo and ballast system, including its control and safety systems. 2.8.2 Integrated cargo and ballast systems meaning any integrated hydraulic and/or electric system used to drive both cargo and ballast pumps (including active control and safety systems and excluding passive components, e.g. piping), shall be designed and constructed as follows: 1) 2) 3) 4)

the emergency stop circuits of the cargo and ballast systems shall be independent from the circuits for the control systems. A single failure in the control system circuits or the emergency stop circuits shall not render the integrated cargo and ballast system inoperative manual emergency stops of the cargo pumps shall be arranged in a way that they shall not cause the stop of the power pack making ballast pumps inoperable the control systems shall be provided with backup power supply, which may be satisfied by a duplicate power supply from the main switch board. The failure of any power supply shall provide audible and visible alarm activation at each location where the control panel is fitted in the event of failure of the automatic or remote control systems, a secondary means of control shall be made available for the operation of the integrated cargo and ballast system. This shall be achieved by manual overriding and/or redundant arrangements within the control systems.

2.9 Gas detection in cargo pump room for flammable liquids with flashpoint not exceeding 60°C 2.9.1 A system for continuous monitoring of the concentration of hydrocarbon gases shall be fitted according to SOLAS II-2 Reg.5.10.1.3. 2.9.2 Sequential sampling is acceptable as long as it is dedicated for the pump room only, including exhaust ducts, and the sampling time is reasonably short. Guidance note: Suitable positions may be the exhaust ventilation duct and lower parts of the pump room above the floor plates. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 68

Part 5 Chapter 6 Section 13

2.8 Integrated cargo and ballast systems

1 General 1.1 Application 1.1.1 All systems covered by this chapter shall be tested in operation. As far as practicable, the tests shall be performed at the building yard. 1.1.2 Remaining function tests, which cannot be carried out without cargo on board, may be carried out in connection with the first cargo loading and transport with a representative cargo.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 69

Part 5 Chapter 6 Section 14

SECTION 14 TESTS AFTER INSTALLATION

1 General requirements 1.1 Application The provisions of this section are applicable where specific reference is made in the IBC code ch.17 column o to corresponding parts of the code. The requirements are mainly of constructional nature or of a nature affecting both construction and operation. Specific operational requirements for some of the products are given in the IBC code. It is assumed that operational requirements are complied with during operation of the ship.

1.2 Materials of construction When cargo tanks are intended for carriage of acids/corrosive products, which in the IBC code ch.17 column o have a reference to 15.11 (or to 15.11.2 or 3), the tanks and associated pipe-lines, valves, fittings and other items of equipment which may come in contact with the cargo, shall be constructed of stainless steel unless fitted with an approved lining.

1.3 Segregation of cargo from bunker tanks Products listed in the IBC code ch.17 column o with reference to 15.12 or 15.12.3, shall not be carried in tanks adjacent to bunker tanks.

1.4 Separate piping systems Products listed in the IBC code ch.17 column o with reference to 15.12 or 15.12.3, shall be carried in tanks with separate piping systems and with vent systems separate from tanks containing other products. Separation of piping systems shall be by spool pieces or similar arrangements enabling visual confirmation of the status of the separation. The requirements for separation of piping systems apply to any cargo handling systems common to and connected to tanks or piping conveying cargo liquid or vapour. Examples of such systems are tank washing systems, inert gas systems, vapour return systems, fixed gas-freeing and drying systems, stripping systems and cargo pipe drainage systems.

1.5 Cargo contamination Water shall not be allowed to contaminate products listed in the IBC code ch.17 column o having reference to 15.16.2. In addition the following provisions apply: — Air inlets to pressure/vacuum relief valves of tanks containing this cargo shall be situated at least 2 m above the weather deck. — Water or steam shall not be used as the heat transfer media in a cargo temperature control system. — This cargo shall not be carried in tanks adjacent to permanent ballast or water tanks unless the tanks are empty and dry. — This cargo shall not be carried in tanks adjacent to sea chests, slop tanks, cargo tanks containing ballast or slops or other cargoes containing water which may react in a dangerous manner. Pumps, pipes or vent lines serving such tanks shall be separate from similar equipment serving tanks containing this cargo. Pipelines from slop tanks or ballast lines shall not pass through tanks containing this cargo unless in a tunnel.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 70

Part 5 Chapter 6 Section 15

SECTION 15 ADDITIONAL REQUIREMENTS FOR CERTAIN CARGOES

1.6.1 For products that in the IBC code ch.17 column h are assigned Inert, the cargo tank vapour space and associated piping systems shall be filled and maintained with a gas (inert) which will not support combustion and which will not react with the cargo. 1.6.2 An adequate supply of inert gas for use in filling and discharging shall be carried or shall be manufactured on board unless a shore supply is available. In addition, sufficient inert gas shall be available on the ship to compensate for normal losses during transportation. 1.6.3 The inert gas system on board the ship shall be able to maintain at least 0.07 bar over-pressure within the containment system at all times. In addition, the inert gas system shall not raise the cargo tank pressure to more than the tank's relief valve setting. 1.6.4 Means shall be provided for monitoring ullage spaces containing a gas blanket to ensure that the correct atmosphere is being maintained. 1.6.5 Inerting arrangements where used with flammable cargoes shall be such as to minimise the creation of static electricity during the admission of the inerting media.

1.7 Moisture control (drying) 1.7.1 For products which in the IBC code ch.17 column h are assigned Dry, the cargo tank vapour space and associated piping systems shall be filled and maintained with a moisture free gas or vapour which will prevent the access of water or water vapour to the cargo. For the purpose of this paragraph, moisture free gas or vapour is that which has a dewpoint of -40°C or below at atmospheric pressure. 1.7.2 Where dry nitrogen is used as the medium, similar arrangements for supply of the drying medium shall be made as required in [1.6.2], [1.6.3] and [1.6.5] above. Where drying agents are used as the drying medium on all air inlets to the tank, sufficient media shall be carried for the duration of the voyage taking into consideration the diurnal temperature range and the expected humidity.

1.8 Cargo pumps in tank For products which in the IBC code ch.17 column o have a reference to 15.18, cargo pumps shall be located in the cargo tank or the cargo pump room shall be located on the weather deck level. Special consideration by the Society is required for other locations of the pump room.

1.9 Products not to be exposed to excessive heat 1.9.1 Products which in the IBC code ch.17 column o have a reference to 16.6 or 16.6.3, shall, due to their heat sensitive nature, not be carried in uninsulated deck tanks. 1.9.2 Products which in the IBC code ch.17 column o have a reference to 16.6 or 16.6.4, shall, due to their heat sensitive nature, not be carried in deck tanks.

1.10 Cargo pump temperature sensors For products which in the IBC code ch.17 column o have a reference to 15.21, temperature sensors shall be used to monitor cargo pumps located in pump rooms, to detect overheating due to pump failure.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 71

Part 5 Chapter 6 Section 15

1.6 Inert gas

For products which in the IBC code ch.17 column o have a reference to 15.17, the ventilation system as described in Sec.10 [2.3.1], shall have a capacity of at least 45 air changes per hour. The ventilation exhaust outlets shall be situated at least 10 m from ventilation inlets to the accommodation and other non-hazardous spaces and at least 4 m above the tank deck.

2 Additional requirements for certain groups of products 2.1 Acids 2.1.1 No electrical equipment or other sources of ignition are permitted in enclosed spaces adjacent to cargo tanks, except as specified in Sec.12. 2.1.2 The ship's shell plating shall not form any boundaries of tanks containing mineral acids. 2.1.3 Materials of construction of the tanks shall be approved in each case. 2.1.4 Proposals for lining steel tanks and related piping systems with corrosion-resistant materials may be considered by the administration. The elasticity of the lining shall not be less than that of the supporting boundary plating. For definition of lining, see Sec.1. (see IACS UR CC6 rev.1) 2.1.5 Unless constructed completely of corrosion-resistant materials or fitted with an approved lining, the plating thickness shall take into account the corrosiveness of the cargo. 2.1.6 Flanges of the loading and discharge manifold connections shall be provided with spray shields which may be portable to guard against the danger of the cargo being sprayed. Drip trays shall be provided to guard against leakage on to the deck. 2.1.7 Means for detecting leakage of cargo into adjacent spaces shall be provided. 2.1.8 Bilge pumping arrangements and drainage arrangements in pump rooms shall be of corrosion resistant materials.

2.2 Products which have a vapour pressure greater than 1.013 bar at 37.8°C 2.2.1 Unless the tank is designed to withstand the vapour pressure of the cargo, provisions shall be made to maintain the temperature of the cargo below its boiling point at atmospheric pressure. 2.2.2 Valved connections for returning gas ashore during loading shall be provided. 2.2.3 Each tank shall be provided with a pressure gauge indicating the pressure in the vapour space above the cargo. 2.2.4 Where the cargo is being cooled, each tank shall be provided with thermometers at the top and bottom of the tank.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 72

Part 5 Chapter 6 Section 15

1.11 Increased ventilation of cargo handling spaces

3.1 Ammonium nitrate solution, 93% or less For applicable requirements, see the IBC code 15.2.

3.2 Carbon disulphide For applicable requirements, see the IBC code 15.3.

3.3 Diethyl ether 3.3.1 Unless inerted, natural ventilation shall be provided for the voids around the cargo tanks while the vessel is under way. If a mechanical ventilation system is installed, all blowers shall be of non-sparking construction. Mechanical ventilation equipment shall not be located in the void spaces surrounding the cargo tanks. 3.3.2 Pressure relief valve settings shall not be less than 0.2 bar. 3.3.3 Inert gas displacement may be used for discharging cargo from pressure vessel tanks provided the cargo system is designed for the expected pressure. 3.3.4 No electrical equipment except for approved lighting fixtures shall be installed in enclosed spaces adjacent to cargo tanks. Lighting fixtures shall be approved for use in diethyl ether vapours. The installation of electrical equipment on the weather deck shall comply with the requirements of Sec.12. 3.3.5 In view of fire hazards, provisions shall be made to avoid any ignition source and/or heat generation in the cargo area. 3.3.6 Pumps may be used for discharging cargo, provided that they are of a type designed to avoid liquid pressure against the shaft gland or are of a submerged type and are suitable for use with the cargo. 3.3.7 Provisions shall be made to maintain the inert gas pad in the cargo tank during loading, unloading and during transit.

3.4 Hydrogen peroxide solutions of 60% but not over 70% by mass For applicable requirements, see the IBC code 15.5.1.

3.5 Hydrogen peroxide solutions over 8% but not over 60% by mass For applicable requirements, see the IBC code 15.5.2 and 15.5.3.

3.6 Phosphorus, yellow or white For applicable requirements, see the IBC code 15.7.

3.7 Propylene oxide and mixtures of ethylene oxid/propylene oxide with ethylene oxide content of not more than 30% by weight 3.7.1 Propylene oxide transported under the provisions of this section shall be acetylene free.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 73

Part 5 Chapter 6 Section 15

3 Additional requirements for certain chemicals

3.7.3 Materials 1)

2)

3) 4)

All valves, flanges, fittings and accessory equipment shall be of a type suitable for use with propylene oxide and shall be constructed of steel or stainless steel or other material acceptable to the Society. The chemical composition of all material used should be submitted for approval prior to fabrication. Discs or disc faces, seats and other wearing parts of valves shall be made of stainless steel containing not less than 11% chromium. Gaskets shall be constructed of materials which do not react with, dissolve in or lower the autoignition temperature of these products and which are fire resistant and possess adequate mechanical behaviour. The surface presented to the cargo shall be polytetrafluoroethylene (PTFE) or materials giving a similar degree of safety by their inertness. Spirally-wound stainless steel with a filler of PTFE or similar fluorinated polymer will be accepted. Insulation and packing, if used, shall be of a material which does not react with, dissolve in, or lower the auto-ignition temperature of these products. The following materials are generally found unsatisfactory for gaskets, packing and similar uses in containment systems for these products and would require testing before being approved: — neoprene or natural rubber if it contacts propylene oxide — materials containing oxides of magnesium, such as mineral wools.

3.7.4 Threaded joints are not permitted in the cargo liquid and vapour lines. 3.7.5 Filling and discharge piping shall extend to within 100 mm of the bottom of the tank or any sump pit. 3.7.6 Containment system 1) 2)

3)

The containment system for a tank containing these products shall have a valved vapour return connection. The products shall be loaded and discharged in such a manner that venting of the tanks to atmosphere does not occur. If vapour return to shore is used during tank loading, the vapour return system connected to a propylene oxide containment system for these products shall be independent from all other containment systems. During discharging operations, the pressure in the cargo tank shall be maintained above 0.07 bar gauge.

3.7.7 Tanks carrying these products shall be vented independently of tanks carrying other products. Facilities shall be provided for sampling the tank contents without opening the tank to the atmosphere. 3.7.8 The cargo may be discharged only by deepwell pumps, hydraulically operated submerged pumps, or inert gas displacement. Each cargo pump shall be arranged to ensure that the oxide does not heat significantly if the discharge line from the pump is shut off or otherwise blocked. 3.7.9 Cargo hoses used for transfer of these products shall be marked: FOR ALKYLENE OXIDE TRANSFER ONLY 3.7.10 Cargo tanks, void spaces and other enclosed spaces, adjacent to an integral gravity cargo tank, shall either contain a compatible cargo or be inerted by injection of a suitable inert gas. Any enclosed space in which an independent cargo tank is located, shall be inerted. Such inerted spaces and tanks shall be monitored for propylene oxide and oxygen. The oxygen content of these spaces shall be maintained below 2%. 3.7.11 Air shall not be allowed to enter the cargo pump or piping system while these products are contained within the system.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 74

Part 5 Chapter 6 Section 15

3.7.2 Tanks for the carriage of propylene oxide shall be of steel or stainless steel construction.

3.7.13 Propylene oxide may be carried in pressure tanks (a4) or in independent (a3) or in integral (a2) gravity tanks. Ethylene oxide/propylene oxide mixtures shall be carried in independent gravity tanks (a3) or in pressure tanks (a4). Tanks shall be designed for the maximum pressure expected to be encountered during loading, conveying and discharging cargo. 3.7.14 Tanks 1) 2)

Cargo tanks with a design pressure less than 0.6 bar gauge and tanks for the carriage of ethylene oxide/ propylene oxide mixtures with a design pressure less than 1.2 bar gauge, shall have a cooling system to maintain the propylene oxide below the reference temperature (see Sec.1 Table 4). The refrigeration requirement for tanks with a design pressure less than 0.6 bar gauge may be waived by the Society for ships operating in restricted areas or in voyages of restricted duration and account may be taken in such cases of any insulation of the tanks. The area and times of year where and for which such carriage would be permitted will be included in the conditions of carriage in the Appendix to the classification certificate. Guidance note: For ships subject to USCG compliance, reference is also made to additional USCG requirements given in 46 CFR 153.370, 153.371 and 153.438. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.7.15 Cooling 1)

2) 3) 4)

Any cooling system shall maintain the liquid temperature below the boiling temperature at the containment pressure. At least two complete cooling plants automatically regulated by variations within the tanks shall be provided. Each cooling plant shall be complete with the necessary auxiliaries for proper operation. The control system shall also be capable of being manually operated. An alarm shall be provided to indicate malfunctioning of the temperature controls. The capacity of each cooling system shall be sufficient to maintain the temperature of the liquid cargo below the reference temperature (see Sec.1 Table 4) of the system. An alternative arrangement may consist of three cooling plants, any two of which shall be sufficient to maintain the liquid temperatures below the reference temperature. Cooling media which are separated from the products by a single wall only, shall be non-reactive with the propylene oxide. Cooling systems requiring compression of propylene oxide shall not be used.

3.7.16 Pressure relief valve settings shall not be less than 0.2 bar gauge, nor greater than 7.0 bar gauge for pressure tanks intended for the carriage of propylene oxide and not greater than 5.3 bar for the carriage of propylene oxide/ethylene oxide mixtures. 3.7.17 Piping 1)

2)

The piping system for tanks intended for these products, shall be completely separate from piping systems for all other tanks, including empty tanks, and from all cargo compressors. If the piping system for the tanks to be loaded is not independent as defined in Sec.1 Table 4, the required piping separation shall be accomplished by the removal of spool pieces, valves, or other pipe sections, and the installation of blank flanges at these locations. The required separation applies to any other possible connections such as common tank washing systems, inert gas/nitrogen systems, vapour return systems, fixed gasfreeing and drying systems, stripping systems and cargo pipe drainage systems. These products may be transported only in accordance with cargo handling plans that have been approved by the Society. Each intended loading arrangement shall be shown on a separate cargo handling plan. Cargo handling plans shall show the entire cargo piping system and the locations for

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 75

Part 5 Chapter 6 Section 15

3.7.12 Prior to disconnecting shore-lines, the pressure in liquid and vapour lines shall be relieved through suitable valves installed at the loading header. Liquid and vapour from these lines shall not be discharged to atmosphere.

Guidance note: When a ship carries propylene oxide or mixtures of ethylene oxide and propylene oxide under IMO's certificate of fitness, the administration or delegated body issuing the certificate will be required to include a reference to the approved cargo handling plans in the certificate. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3)

Before loading propylene oxide, certification verifying that the required piping separation has been achieved shall be obtained from a representative of the Society and carried on board the ship. Each connection between a blank flange and pipeline flange shall be fitted with a wire and seal by the Society's representative to ensure that inadvertent removal of the blank flange is impossible.

3.7.18 The maximum allowable tank filling limits for each cargo tank shall be indicated for each loading temperature which may be applied and for the applicable maximum reference temperature, on a list to be approved by the Society. A copy of the list shall be permanently kept on board by the master. 3.7.19 The cargo shall be carried under a suitable protective padding of nitrogen gas. An automatic nitrogen make-up system shall be installed to prevent the tank pressure falling below 0.07 bar gauge in the event of product temperature fall due to ambient conditions or maloperation of refrigeration systems. Sufficient nitrogen shall be available on board to satisfy the demand of the automatic pressure control. Nitrogen of acceptable purity shall be used for padding. 3.7.20 The nitrogen system shall be capable of inerting the tank vapour space to an oxygen content of less than 2% prior to loading and maintaining this content during the voyage. 3.7.21 A water-spray system shall be provided in the area where loading and unloading operations are conducted. The capacity and arrangement shall be such as to blanket effectively the area surrounding the loading manifold and the exposed deck pipework associated with product handling. The arrangement of piping and nozzles shall be such as to give a uniform distribution over the entire area protected at a 2 discharge rate of 10 l/m /minute. Remote manual operation should be arranged such that remote starting of pumps supplying the water spray system and remote operation of any normally closed valves in the system can be carried out from a suitable location outside the cargo area, adjacent to the accommodation spaces and readily accessible and operable in the event of fire in the areas protected. The water-spray system shall be capable of both local and remote manual operation and the arrangement shall ensure that any spilled cargo is washed away. Additionally, a water hose with pressure to the nozzle, when atmospheric temperatures permit, shall be connected ready for immediate use during loading and unloading operations. Guidance note: For ships subject to USCG compliance, reference is also made to additional USCG requirements to such systems given in 46 CFR 153.530 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.7.22 A remote operational, controlled closing-rate shut-off valve shall be provided at the manifold for each cargo hose connection used during cargo transfer.

3.8 Sulphuric acid 3.8.1 The following sulphuric acids will be accepted for the carriage in unlined mild steel tanks: — 96% (66° Be) or higher concentrations — 78% (60° Be) or higher with or without an inhibitor, provided the corrosive effect on mild steel at 25°C is not higher than that of 96% (66° Be) commercial sulphuric acid — spent sulphuric acid from industrial processes, provided the corrosive effect is not higher than that stated above.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 76

Part 5 Chapter 6 Section 15

installation of blank flanges needed to meet the above piping separation requirements. A copy of each approved cargo handling plan shall be maintained on board the ship.

3.8.3 Cargo pumps, piping and valves made from nodular cast iron, will be accepted for the following sulphuric acids: — 65% (51.7° Be) or higher concentrations — spent sulphuric acid from industrial processes, provided the corrosive effect is not higher than that stated above. 3.8.4 P/V-valves and vent pipes from the cargo tank shall be made of or protected by acid-resistant materials. Vent pipes to unprotected cargo tanks shall extend about 50 mm into the tank. 3.8.5 Drip pans shall be provided below pump glands and at shore connections. 3.8.6 The bilge piping and pumping system in pump rooms shall be made of or lined with corrosion-resistant material.

3.9 Sulphur liquid 3.9.1 Cargo tank ventilation shall be provided to maintain the concentration of H2S below one half of its lower explosive limit throughout the cargo tank vapour space for all conditions of carriage, i.e. below 1.85% by volume. 3.9.2 Where mechanical ventilation systems are used for maintaining low gas concentrations in cargo tanks, ventilation failure alarm shall be provided. 3.9.3 Ventilation systems shall be designed and arranged to preclude depositing of sulphur within the system. 3.9.4 Openings to void spaces adjacent to cargo tanks shall be designed and fitted to prevent the entry of water, sulphur or cargo vapour. 3.9.5 Connections shall be provided to enable sampling and analysis of vapour in void spaces. 3.9.6 An automatic temperature control system for the cargo shall be fitted in order to ensure that the temperature of the sulphur does not exceed 155°C. A high temperature alarm shall be fitted.

3.10 Alkyl (C7 - C9) nitrates 3.10.1 The carriage temperature on the cargo shall be maintained below 100°C to prevent the occurrence of a self-sustained, exothermic decomposition reaction. 3.10.2 The cargo may not be carried in independent pressure tanks (a4) permanently affixed to the ship's deck unless: 1) 2)

the tanks are sufficiently insulated from fire, and the ship has a water deluge system for the tanks such that the cargo temperature is maintained below 100°C and the temperature rise in the tanks does not exceed 1.5°C/hour for a fire of 650°C.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 77

Part 5 Chapter 6 Section 15

3.8.2 Sulphuric acid of other qualities and concentrations than stated in [3.8.1], shall be carried in tanks lined or made from suitable acid-resistant materials. These will be subject to special consideration by the Society.

1 General 1.1 Application 1.1.1 Chemical tankers of 8000 tonnes deadweight and upwards, constructed on or after 1 January 2016 shall be fitted with a fixed inert gas system. Requirements given for inert gas plants in the FSS Code Ch. 15 as amended by IMO Res. MSC.367(93) shall apply. Chemical tankers when transporting oil with flashpoint not exceeding 60°C shall comply with the inert gas requirements of SOLAS Reg. II-2/4.5.5. Ch. 15 of the FSS code as amended by IMO Res. MSC.367(93) have been included in table C1. SOLAS II-2 Reg. 16 as amended by IMO Res. MSC.365(93), specifies that for chemical tankers, when carrying flammable chemicals, the application of inert gas, may take place after the cargo tank has been loaded, but before commencement of unloading and shall continue to be applied until that cargo tank has been purged of all flammable vapours before gas-freeing. Only nitrogen is acceptable as inert gas under this provision. For ships that intend to apply this option, nitrogen generators with capacity of 125% of the maximum discharge rate shall be installed. 1.1.2 Chemical tankers of 8000 tonnes deadweight and upwards constructed on or after 1 January 2016 shall be fitted with a fixed inert gas system. Requirements given for inert gas plants in Ch.5 Sec.11 shall be followed. Guidance note: 1)

Oxygen alarm setting will from the date 01.01.2016 be reduced from 8% to 5%.

2)

Inerting of cargo tanks are from the date 01.01.2016 allowed after the completion of cargo loading. In that case nitrogen is the only acceptable inert gas medium.

Reference is also made to IMO Res. MSC.365(93). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Documentation Documentation in accordance with Sec.1 Table 5 shall be submitted for approval.

2 Materials, arrangement and design 2.1 General 2.1.1 Inert gas systems shall satisfy the requirements of Ch.5 Sec.11 to the extent these requirements are applicable. Certification requirements for components in inert gas systems and nitrogen systems based on separation of air, are given in Sec.1 Table 6. Alternative solutions to specific requirements in above rules may be accepted as follows: 1)

The water seal required by Ch.5 Sec.11 may be replaced by an alternative arrangement consisting of two automatically operated shut-off valves in series with a venting valve in between (double block and bleed). The following conditions apply: — The operation of the valve shall be automatically executed. Signals for opening and closing shall be taken from the process directly, e.g. inert gas flow or differential pressure. An arrangement where nitrogen supply directly from the process is used to control the valves (maintain block valves open and bleed valve closed) may be accepted, provided that nitrogen supply pressure is higher than the

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 78

Part 5 Chapter 6 Section 16

SECTION 16 INERT GAS SYSTEMS

2)

A lower capacity of the system than that required by Ch.5 Sec.11 [4] may be accepted on the condition that the cargo discharge rate from tanks being protected is restricted to 80% of the inert gas capacity. An entry to this effect will be made in the appendix to the classification certificate.

2.1.2 An inert gas system based on production of inert gas by other means than combustion of hydrocarbons may be accepted upon special considerations.

2.2 Inert gas systems based on other means than combustion of hydrocarbons 2.2.1 The requirements of [2.2] are specific for the gas generator system and apply when inert gas is produced by passing compressed air through hollow fibres, semi-permeable membranes or absorber materials. 2.2.2 The system shall be provided with at least two air compressors. 2.2.3 A feed air treatment system shall be fitted to remove water, particles and traces of oil from the compressed air. 2.2.4 The air compressor and the nitrogen generator may be installed in the engine room or in a separate compartment. The separate compartment is allowed positioned in the cargo area subject to hazardous zone consideration. When installed in a separate compartment, the compartment shall be treated as one of other machinery spaces with respect to fire protection. 2.2.5 Where a separate compartment is provided, it shall be fitted with an independent mechanical extraction ventilation system, providing 6 air changes per hour. Two oxygen sensors (low oxygen alarms) shall be fitted and give audible and visual alarm outside the door. The compartment shall have no direct access to accommodation spaces, service spaces or control stations. 2.2.6 Where fitted, a nitrogen receiver or buffer tank may be installed in a dedicated compartment or in the separate compartment containing the air compressor and the generator, in the engine room, or may be located in the cargo area. Where the nitrogen receiver or buffer tank is installed in an enclosed space, the access shall be arranged only from the open deck and the access door shall open outwards. Permanent ventilation and alarm shall be fitted as required in [2.2.5]. 2.2.7 Nitrogen separating systems that may be destroyed by high temperature in the supply air, shall be arranged with an alarm and automatic shutdown of the system upon alarm conditions. Table 1 Certification of nitrogen generator system components Equipment

Certificate type

Deck water seal

NV-P

Sea water pumps for deck water seal

NV-P

Liquid P/V breaker

W-P

Dryer (absorption/refrigerant)*

NV-P

Control and monitoring system

NV-P

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Comment

If pressure vessel (e.g. swing type).

Page 79

Part 5 Chapter 6 Section 16

pressure setting of the cargo tank P/V-valves and provided that the valves automatically return to safe position in the event of loss of nitrogen supply. — Valves shall be provided with position indication. An alarm for faulty operation of the valves shall be provided, e.g. the operational status of blower stop and supply valve(s) open is an alarm condition.

Certificate type

Electrical motors and motor starters

Comment See Pt.4 Ch.8 Sec.1.

Membrane separation vessels

NV-P

Air compressor ≤ 100 kW

W-P

Air compressor > 100 kW

NV-P

Cooling water pumps for compressors

NV-P

Pressure vessels containing N2 (e.g. buffer tanks)

NV-P

(if pressure vessels with p × V > 1.5.

(normally air cooled)

NV-P = DNV GL product certificate, W-P = Maker's (works) product certificate, NV-TA = DNV GL type approval *Electric motors pertaining serving dryers are not required delivered with DNV GL product certificate or type approval certificate.Manufacturer's (works) certificate only is required, regardless of size.

2.2.8 The oxygen-enriched air from the nitrogen generator and the nitrogen-product enriched gas from the protective devices of the nitrogen receiver shall be discharged to a safe location on the open deck. 1)

oxygen-enriched air from the nitrogen generator - safe locations on the open deck are: — outside of hazardous area — not within 3 m of areas traversed by personnel — not within 6 m of air intakes for machinery (engines and boilers) and all ventilation inlets.

2)

nitrogen-product enriched gas from the protective devices of the nitrogen receiver - safe locations on open deck are: — not within 3 m of areas traversed by personnel — not within 6 m of air intakes for machinery (engines and boilers) and all ventilation inlets/outlets.

See IACS UR F20.

2.3 Nitrogen inert gas systems fitted for other purposes 2.3.1 If an inert gas system is fitted for other applications than stated in [1.1.1], the requirements in [2.2] apply. However, only one air compressor is required and a permanent recording of the parameters in Ch.5 Sec.11 is not mandatory. 2.3.2 Where the connections to the hold spaces or to the cargo piping are not permanent, two non-return valves may substitute the non-return devices required in Ch.5 Sec.11 [3.6.2] and Ch.5 Sec.11 [3.6.3], see IACS UR F20.. Guidance note: Cargo tank connections for inert gas padding, as required for the carriage of certain products, are considered permanent, for the purpose of this requirement. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 80

Part 5 Chapter 6 Section 16

Equipment

3.1 General 3.1.1 Inert gas systems shall satisfy the requirements of Ch.5 Sec.11 [5] to the extent these requirements are applicable. In addition, for inert gas generator systems where nitrogen is produced by passing compressed air through hollow fibres, semi-permeable membranes or absorber materials, the requirements in Table 2 shall apply. Table 2 Control and Monitoring of inert gas plants based on nitrogen separation

Failure/ indication

Operational status of the inert gas system

Setting

-

Permanent recording

-

Continuous indication

CCR

1)

Alarm

-

Activation Shut-down Automatic of of gas shutdoubleregulating down of block and valve compressors 2) bleed

-

-

Comment

-

Indication showing that inert gas is being produced and delivered to 6) cargo area.

Operational status of the isolation valves between IG main and cargo 7) tanks

-

-

-

-

-

-

-

Position indicators providing open/ intermediate/ close status information in the control panel.

Oxygen 5) content

-

CCR

ECR and CCR

-

-

-

-

-

-

-

-

-

Shall be active also when the plant is not in use.

Pressure in IG 4) main

-

CCR

ECR, CCR and Bridge

IG supply temperature

-

-

ECR and CCR

-

-

-

-

-

High oxygen 5) content

> 5%

-

-

CCR and ECR

X

-

-

-

Low pressure 4) IG main

< 100 mm

-

-

CCR and ECR

-

-

-

-

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 81

Part 5 Chapter 6 Section 16

3 Instrumentation

Low-low pressure IG main

High pressure 4) IG main

Setting

Permanent recording

Continuous indication

1)

Alarm

< 50 mm

-

-

CCR or automatic shut-down of cargo pumps with alarm

-

-

-

CCR

Comment

Shall be independent of the lowpressure alarm, i.e. separate pressure transmitter.

-

-

-

-

-

-

-

Low level in deck water seal

-

-

-

CCR

-

-

-

Shall be active also when the IG plant is not in use.

Failure of air compressors

-

-

-

CCR

X

-

-

-

Power failure of the control and monitoring system

-

-

-

CCR and ECR

-

-

-

-

-

CCR and ECR

-

Shall be active also when the plant is not in use.

Power failure to oxygen and pressure indicators and recorders

-

-

-

-

Oxygen level in inert gas room(s)

< 19% O2

-

-

Outside space and ECR

-

-

-

Min. 2 oxygen sensors shall be provided in each space. Visual and audible alarm at entrance to the inert gas room(s).

Power failure of the N2 generator

-

-

-

CCR

-

-

-

-

Loss of inert gas supply (flow of differential pressure)

-

-

-

CCR

X

-

X

-

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 82

Part 5 Chapter 6 Section 16

Failure/ indication

Activation Shut-down Automatic of of gas shutdoubleregulating down of block and valve compressors 2) bleed

Setting

Permanent recording

Continuous indication

Faulty operation of double-block and bleed valves

-

-

-

CCR

-

-

-

Double-block and bleed valve position

-

-

CCR

-

-

-

-

-

Loss of power to doubleblock and bleed or Nitrogen generator

-

-

-

-

-

-

X

-

1)

Alarm

Comment

See footnote 3) .

Air temperature at suction side of the nitrogen generator (after compressors and coolers if fitted)

75°C

-

CCR

CCR

X

X

-

Manufacturer's alarm settings may apply, but shall not exceed that specified in Sec.7 [1.1.11].

Air pressure at suction side of the N2 generator

-

-

CCR

-

-

-

-

-

Failure of electric heater (if fitted)

-

-

-

CCR

-

-

-

-

Low feed air pressure from the compressor

-

-

-

CCR

-

-

-

-

High condensate level at automatic drain of water separator

-

-

-

CCR

-

-

-

-

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 83

Part 5 Chapter 6 Section 16

Failure/ indication

Activation Shut-down Automatic of of gas shutdoubleregulating down of block and valve compressors 2) bleed

Setting

Permanent recording

Continuous indication

1)

Alarm

Comment

- = not applicable; X = applicable. 1) Alarms shall be audible and visible. 2) Applicable only for ships with double-block and bleed replacing deck water seals. 3) Faulty operation of double-block and bleed valves: — one block valve open and other block valve closed — bleed-valve open and block valves open — bleed-valve closed and block valves closed — block valves open when there is no inert gas supply. 4) A common pressure transmitter is acceptable. 5) A common oxygen sensor is applicable. 6) The indication shall be based on the operational status of the gas regulating valve and on the pressure or flow of the inert gas mains forward of the non-return devices. However, the operational status of the IG system is not considered to require additional indicators and alarms other than those specified in the FSS Code. 7) Limit switches shall be used to positively indicate both open and closed position. Intermediate position status shall be indicated when the valve is in neither open nor closed position.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 84

Part 5 Chapter 6 Section 16

Failure/ indication

Activation Shut-down Automatic of of gas shutdoubleregulating down of block and valve compressors 2) bleed

1 General requirements 1.1 Protective equipment 1.1.1 For the protection of crew members who are engaged in loading and discharging operations, the ship shall have on board suitable protective equipment consisting of large aprons, special gloves with long sleeves, suitable footwear, coveralls of chemical-resistant material, and tight-fitting goggles or face shields or both. The protective clothing and equipment shall cover all skin so that no part of the body is unprotected. Six (6) sets of protective clothing and equipment shall be carried onboard. 1.1.2 Work clothes and protective equipment shall be kept in easily accessible places and in special lockers. Such equipment shall not be kept within accommodation spaces, with the exception of new, unused equipment and equipment which has not been used since undergoing a thorough cleaning process. Storage rooms for such equipment may, however, upon special consideration be approved within accommodation spaces if adequately segregated from living spaces such as cabins, passageways, dining rooms, bathrooms, etc.

2 Safety equipment 2.1 Safety equipment 2.1.1 Ships intended for carriage of toxic products for which the IBC Code Ch.17 column o refers to 15.12, 15.12.1 or 15.12.3, shall have on board sufficient, but not less than three complete sets of safety equipment each permitting personnel to enter a gas filled compartment and perform work there for at least 20 minutes. Such equipment shall be additional to that required by SOLAS regulation II-2/10.10. 2.1.2 One complete set of safety equipment shall consist of: 1) 2) 3) 4)

one self-contained air-breathing apparatus (not using stored oxygen) protective clothing, boots, gloves and tight-fitting goggles fireproof lifeline with belt resistant to the cargoes carried explosion-proof lamp.

2.1.3 For the safety equipment required in [2.1.1], all ships shall carry the following, either items 1) through 3) or 4), from the following list: 1) 2) 3) 4)

one set of fully charged spare air bottles for each breathing apparatus a special air compressor suitable for the supply of high-pressure air of the required purity a charging manifold capable of dealing with sufficient spare breathing apparatus air bottles for the breathing apparatus fully charged spare air bottles with a total free air capacity of at least 6 000 l for each breathing apparatus on board in excess of the requirements of SOLAS regulation II-2/10.10.

2.1.4 A cargo pump-room on ships carrying cargoes subject to the requirements of Sec.15 [1.8] or cargoes for which in the IBC code ch.17 column k, toxic vapour detection equipment is required, but is not available, shall have either item 1) or 2) from the following list: 1)

a low-pressure line system with hose connections suitable for use with the breathing apparatus required by [2.1.1]. This system shall provide sufficient high-pressure air capacity to supply, through pressure reduction devices, enough low-pressure air to enable two men to work in a hazardous space for at

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 85

Part 5 Chapter 6 Section 17

SECTION 17 PERSONNEL PROTECTION

2.1.5 At least one set of safety equipment as required by [2.1.2] shall be kept in a suitable clearly marked locker in a readily accessible place near the cargo pump-room. The other sets of safety equipment should also be kept in suitable, clearly marked, easily accessible, place. 2.1.6 A stretcher which is suitable for hoisting an injured person up from spaces such as the cargo pumproom, shall be placed in a readily accessible location. 2.1.7 Ships intended for the carriage of products which in the IBC Code Ch.17 column n are assigned yes, shall be provided with suitable respiratory and eye protection sufficient for every person on board for emergency escape purposes, subject to the following: 1) 2)

self-contained breathing apparatus shall normally have a duration of service of at least 15 min emergency escape respiratory protection shall not be used for fire-fighting or cargo handling purposes and should be marked to that effect.

2.1.8 For ships intended for the carriage of products which in the IBC code ch.17 column n are assigned yes, lifeboats shall be provided with a self-contained air support system complying with the requirements of the international life-saving appliance (LSA) code.

3 Medical first-aid equipment 3.1 General The ship shall have on board medical first-aid equipment including oxygen resuscitation equipment and antidotes for cargoes carried based on the guidelines developed by IMO. Guidance note: See the Medical First Aid Guide for Use in Accidents Involving Dangerous Goods (MFAG) which provides advice on the treatment of casualties in accordance with the symptoms exhibited as well as equipment and antidotes that may be appropriate for treating the casualty. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4 Decontamination showers and eye washes 4.1 General Suitably marked decontamination showers and eyewashes shall be available on deck in convenient locations. The showers and eyewashes shall be operable in all ambient conditions. Decontamination shower and eye wash units should be located on both sides of the ship in the cargo manifold area and at the aft end of the cargo area. A heating system with temperature control is considered required. Water supply capacity shall be sufficient for simultaneous use of at least two units. Guidance note: Thermal insulation is not considered as an alternative to a system with temperature control. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 86

Part 5 Chapter 6 Section 17

2)

least 1 h without using the air bottles and breathing apparatus air bottles from a special air compressor suitable for the supply of high-pressure air of the required purity an equivalent quantity of spare bottled air in lieu of the low-pressure air line.

January 2017 edition

Main changes January 2017, entering into force July 2017 • Sec.1 General — Sec.1 Table 4: Definition of cargo area has been updated to reflect that it also includes full depth of the ship. — Sec.1 Table 6: In Table 6, a note has been inserted under additional description indicating requirement for EC-MED certificates for P/V valves for EEA flagged vessels.

• Sec.3 Ship arrangements — Sec.3 [5]: Headline has been amended to include deck trunks. — Sec.3 [5.1.8]: Requirements for deck trunks according to IMO MSC/Circ.1276 has been introduced. — Sec.3 [9.1.3]: Guidance note has been amended.

• Sec.16 Inert gas systems — Sec.16 [1.1.1] and Sec.16 [1.1.2]: Text related to deadweight requirements has been rephrased in order to be aligned between 1.1.1 and 1.1.2. — Sec.16 [2.2.6]: Requirement to location of nitrogen system components including nitrogen buffer tanks have been amended in accordance with FSS code Ch.15 2.4.1.4. — Sec.16 Table 2: Has been amended in accordance with forthcoming IACS unified Interpretation to the FSS code.

July 2016 edition

Main changes July 2016, entering into force 1 January 2017 • Sec.1 General — Sec.1 Table 1 and Sec.1 Table 2: Notations Barge for chemicals, Barge for C and Barge for chemicals with flashpoint above 60°C have been included. — Sec.1 Table 4: Definition of cargo tank block has been amended to include extending to the full depth of the ship. — Sec.1 Table 6: Certificate issuer for emergency towing strong points changed from "Society" to "manufacturer".

• Sec.2 Hull — Sec.2 [2.3.5]: Requirements to manifold valves have been updated to be more in line with OCIMF recommendation.

• Sec.16 Inert gas systems — Sec.16 Table 2: The comment for "Operational status of the inert gas system" has been amended and footnote 6) has been removed.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 87

Part 5 Chapter 6 Changes – historic

CHANGES – HISTORIC

Part 5 Chapter 6 Changes – historic

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Amendments January 2016 • General — Only editorial corrections have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.6. Edition July 2017 Chemical tankers

DNV GL AS

Page 88

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition January 2018

Part 5 Ship types Chapter 7 Liquefied gas tankers

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the July 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.7. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018 Topic Update of Gas Carrier Rules DNVGL Rules Pt.5 Ch.7

Reference

Description

Sec.1 Table 5

Definition on cargo tank design temperature following text has been deleted: "provisions to the satisfaction of the Society shall be made so that the tank or cargo temperature cannot be lowered below the design temperature". Text has been added in Sec.4 [1.1.3].

Sec.3 [3.1.5]

Guidance note: Deleted as it was not per rule requirement in the paragraph.

Sec.5 [5.3.7]

Removed. The requirement was a duplicate of [5.2.2].

Sec.7 [3.1.2]

Removed LNG as this is also relevant for other cargoes.

Sec.7 [4]

Re-phrased title.

Sec.8 [2.2]

Heading removed as not relevant for all subsections. Heading "Valve testing" made to new subheading at lower level. References updated accordingly.

Sec.12 [1.1.7]

Deleted following text to align with IGC Code: "unless the motor is certified for the same hazard zone as the space served".

Sec.13 [11.1.1]

Added guidance note related to gas combustion unit.

Sec.13 Table 6

Added new row for reliquefication plant (Brayton cycle) and renamed gas combustion unit to thermal oxidation vapour system to be aligned with IGC Code.

Sec.17 [11]

Guidance note for CO2 deleted as it was not aligned with 2016 IGC Code.

Sec.20 [5.5.1]

Added the following: "A minimum safety factor of 2 may be accepted for AC-III acceptance criteria.".

Sec.22 [1.1.1]

Added: For the design with single side hull structure, it shall be evaluated according to Sec.20 [1.6] as relevant.

Sec.22 [2.8.6]

Acceptance criteria for accidental load case modified.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 3

Part 5 Chapter 7 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General requirements.......................................................................... 20 1 Introduction.......................................................................................20 1.1 Introduction................................................................................... 20 1.2 Scope............................................................................................ 20 1.3 Application..................................................................................... 20 1.4 Class notations............................................................................... 20 2 General.............................................................................................. 22 2.1 General..........................................................................................22 2.2 Tank types..................................................................................... 23 3 Definitions..........................................................................................24 3.1 Terms............................................................................................ 24 3.2 Symbols.........................................................................................29 4 Documentation...................................................................................30 4.1 Documentation requirements............................................................30 5 Certification requirements................................................................. 36 5.1 General..........................................................................................36 5.2 Certification of components..............................................................36 5.3 Material certification of cargo pipe systems and cargo components........ 38 5.4 Documentation requirements for manufacturers..................................39 6 Testing............................................................................................... 40 6.1 Testing during newbuilding...............................................................40 7 Signboards......................................................................................... 41 7.1 References..................................................................................... 41 Section 2 Ship survival capability and location of cargo tanks.............................. 42 1 General.............................................................................................. 42 1.1 Requirements and definitions........................................................... 42 2 Freeboard and stability......................................................................42 2.1 General requirements...................................................................... 42 3 Damage assumptions.........................................................................44 3.1 Maximum extent of damage.............................................................44 4 Location of cargo tanks..................................................................... 45 4.1 General requirements...................................................................... 45 5 Flood assumptions............................................................................. 54 5.1 General requirements...................................................................... 54

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 4

Part 5 Chapter 7 Contents

CONTENTS

6.1 Damage related to ship types.......................................................... 55 7 Survival of ship..................................................................................56 7.1 General requirements...................................................................... 56 Section 3 Ship arrangements................................................................................ 57 1 Segregation of the cargo area........................................................... 57 1.1 General requirements...................................................................... 57 2 Accommodation, service and machinery spaces and control station.................................................................................................. 57 2.1 General requirements...................................................................... 57 3 Cargo machinery spaces and turret compartments............................ 59 3.1 General requirements...................................................................... 59 4 Cargo control rooms.......................................................................... 60 4.1 General requirements...................................................................... 60 5 Access to spaces in the cargo area....................................................60 5.1 General requirements...................................................................... 60 6 Airlocks.............................................................................................. 66 6.1 General requirements...................................................................... 66 7 Bilge, ballast and oil fuel arrangements............................................ 66 7.1 General requirements...................................................................... 66 8 Bow and stern loading and unloading arrangements......................... 67 8.1 General requirements...................................................................... 67 9 Cofferdams and pipe tunnels............................................................. 68 9.1 General requirements...................................................................... 68 10 Guard rails and bulwarks.................................................................68 10.1 Arrangement.................................................................................68 11 Diesel engines driving emergency fire pumps or similar equipment forward of cargo area......................................................... 68 11.1 General requirements.................................................................... 68 12 Chain locker and windlass............................................................... 68 12.1 General requirements.................................................................... 68 13 Anodes and other fittings in tanks and cofferdams..........................69 13.1 General requirements.................................................................... 69 14 Emergency towing........................................................................... 69 14.1 General requirements.................................................................... 69 Section 4 Cargo containment................................................................................ 70 1 General.............................................................................................. 70 1.1 Definitions......................................................................................70

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 5

Part 5 Chapter 7 Contents

6 Standard of damage.......................................................................... 55

2 Cargo containment.............................................................................70 2.1 Functional requirements...................................................................70 2.2 Cargo containment safety principles.................................................. 72 2.3 Secondary barriers in relation to tank types....................................... 73 2.4 Design of secondary barriers............................................................ 73 2.5 Partial secondary barriers and primary barrier small leak protection system................................................................................................ 74 2.6 Supporting arrangements.................................................................74 2.7 Associated structure and equipment..................................................75 2.8 Thermal insulation.......................................................................... 75 3 Design loads...................................................................................... 75 3.1 General..........................................................................................75 3.2 Permanent loads............................................................................. 75 3.3 Functional loads..............................................................................76 3.4 Environmental loads........................................................................ 77 3.5 Accidental loads..............................................................................78 4 Structural integrity............................................................................ 78 4.1 General..........................................................................................78 4.2 Structural analyses......................................................................... 79 4.3 Design conditions............................................................................79 5 Materials and construction................................................................ 83 5.1 Materials........................................................................................ 83 5.2 Construction processes.................................................................... 86 5.3 Welding procedure tests.................................................................. 87 5.4 Welding production tests..................................................................87 5.5 Requirements for weld types and non-destructive testing..................... 88 6 Guidance............................................................................................ 90 6.1 Guidance for section 4.................................................................... 90 Section 5 Process pressure vessels and liquids, vapour and pressure piping systems.................................................................................................................96 1 General.............................................................................................. 96 1.1 General requirements...................................................................... 96 2 System requirements.........................................................................96 2.1 General requirements...................................................................... 96 2.2 General arrangements..................................................................... 96 3 Arrangements for cargo piping outside the cargo area...................... 97 3.1 Emergency cargo jettisoning............................................................ 97 3.2 Bow and stern loading arrangements................................................ 97

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 6

Part 5 Chapter 7 Contents

1.2 Application..................................................................................... 70

3.4 Gas fuel piping systems.................................................................. 98 4 Design pressure................................................................................. 98 4.1 Minimum design pressure for piping, piping systems and components.... 98 5 Cargo system valve requirements......................................................99 5.1 General requirements...................................................................... 99 5.2 Cargo tank connections................................................................... 99 5.3 Cargo manifold connections............................................................. 99 6 Cargo transfer arrangements...........................................................100 6.1 General........................................................................................ 100 6.2 Vapour return connections..............................................................100 6.3 Cargo tank vent piping systems......................................................100 6.4 Cargo sampling connections........................................................... 101 6.5 Cargo filters................................................................................. 101 7 Installation requirements................................................................ 101 7.1 Design for expansion and contraction.............................................. 101 7.2 Precautions against low-temperature............................................... 101 7.3 Water curtain................................................................................102 7.4 Bonding....................................................................................... 102 8 Piping fabrication and joining details.............................................. 102 8.1 General........................................................................................ 102 8.2 Direct connections.........................................................................102 8.3 Flanged connections...................................................................... 103 8.4 Expansion joints............................................................................103 8.5 Other connections......................................................................... 103 9 Welding, post-weld heat treatment and non-destructive testing......103 9.1 General........................................................................................ 103 9.2 Post-weld heat treatment............................................................... 103 9.3 Non-destructive testing.................................................................. 103 10 Installation requirements for cargo piping outside the cargo area.................................................................................................... 104 10.1 Bow and stern loading arrangements............................................. 104 10.2 Turret compartment transfer systems............................................ 104 10.3 Gas fuel piping........................................................................... 105 11 Piping system component requirements........................................ 105 11.1 General...................................................................................... 105 11.2 Allowable stress.......................................................................... 106 11.3 High pressure gas fuel outer pipes or ducting scantlings................... 106 11.4 Stress analysis............................................................................ 107

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 7

Part 5 Chapter 7 Contents

3.3 Turret compartment transfer systems................................................ 98

11.6 Ships' cargo hoses...................................................................... 108 12 Materials........................................................................................ 108 12.1 General...................................................................................... 108 12.2 Cargo piping insulation system..................................................... 108 13 Testing and construction............................................................... 109 13.1 Valves........................................................................................ 109 13.2 Expansion bellows....................................................................... 110 13.3 Piping system testing requirements............................................... 110 13.4 Emergency shutdown valves......................................................... 111 13.5 Pumps........................................................................................111 13.6 Cargo process pressure vessels.....................................................111 Section 6 Materials of construction, quality control and marking........................112 1 General............................................................................................ 112 1.1 Definitions.................................................................................... 112 2 Scope............................................................................................... 112 2.1 General requirements.................................................................... 112 3 General test requirements and specifications.................................. 113 3.1 Tensile tests................................................................................. 113 3.2 Toughness tests............................................................................ 113 3.3 Bend test..................................................................................... 115 3.4 Section observation and other testing..............................................115 4 Requirements for metallic materials................................................ 115 4.1 General requirements for metallic materials......................................115 5 Welding of metallic materials and non-destructive testing.............. 122 5.1 General........................................................................................ 122 5.2 Welding consumables.....................................................................122 5.3 Welding procedure tests for cargo tanks and process pressure vessels.. 122 5.4 Welding procedure tests for piping.................................................. 124 5.5 Production weld tests.................................................................... 124 5.6 Non-destructive testing.................................................................. 124 6 Other requirements for construction in metallic materials............... 125 6.1 General........................................................................................ 125 6.2 Independent tank..........................................................................125 6.3 Secondary barriers........................................................................ 126 6.4 Semi-membrane tanks...................................................................126 6.5 Membrane tanks........................................................................... 127 7 Non-metallic materials.....................................................................127

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 8

Part 5 Chapter 7 Contents

11.5 Flanges, valves and fittings.......................................................... 107

8 Hull materials.................................................................................. 127 8.1 Inner hull structure....................................................................... 127 8.2 Outer hull structure.......................................................................127 8.3 Secondary barrier......................................................................... 127 9 Marking of tanks, pipes and valves..................................................128 9.1 General requirements.................................................................... 128 Section 7 Cargo pressure - temperature control................................................. 129 1 Methods of control...........................................................................129 1.1 General requirements.................................................................... 129 2 Design of systems........................................................................... 129 2.1 General requirements.................................................................... 129 3 Re-liquefaction of cargo vapours..................................................... 130 3.1 General requirements.................................................................... 130 3.2 Compatibility................................................................................ 130 4 Thermal oxidation of vapours, i.e gas combustion........................... 131 4.1 General........................................................................................ 131 4.2 Thermal oxidation systems............................................................. 131 4.3 Burners........................................................................................ 131 4.4 Safety..........................................................................................132 5 Pressure accumulation systems.......................................................132 5.1 General requirements.................................................................... 132 6 Liquid cargo cooling........................................................................ 132 6.1 General requirements.................................................................... 132 7 Segregation......................................................................................132 7.1 General requirements.................................................................... 132 8 Availability....................................................................................... 133 8.1 General requirements.................................................................... 133 9 Cargo heating arrangements........................................................... 133 9.1 General requirements.................................................................... 133 Section 8 Vent system for cargo containment system........................................ 134 1 General............................................................................................ 134 1.1 General requirements.................................................................... 134 2 Pressure relief systems................................................................... 134 2.1 General requirements.................................................................... 134 3 Vacuum protection systems.............................................................136 3.1 General requirements.................................................................... 136

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 9

Part 5 Chapter 7 Contents

7.1 General........................................................................................ 127

4.1 Sizing of pressure relief valves....................................................... 137 4.2 Sizing of vent pipe system............................................................. 140 4.3 Upstream pressure losses.............................................................. 140 4.4 Downstream pressure losses.......................................................... 140 5 Pressure relief devices.................................................................... 141 5.1 General........................................................................................ 141 Section 9 Cargo containment system atmospheric control.................................. 143 1 Atmosphere control within the cargo containment system.............. 143 1.1 General requirements.................................................................... 143 1.2 Atmosphere control within the hold spaces (cargo containment systems other than type C independent tanks)...................................... 143 1.3 Environmental control of spaces surrounding type C independent tanks.................................................................................................144 1.4 Inerting........................................................................................144 2 Inert gas production on board.........................................................145 2.1 General requirements.................................................................... 145 2.2 Nitrogen systems.......................................................................... 145 Section 10 Electrical installations....................................................................... 147 1 General............................................................................................ 147 1.1 General........................................................................................ 147 1.2 Definitions.................................................................................... 147 1.3 General requirements.................................................................... 147 2 Area classification............................................................................148 2.1 General requirements.................................................................... 148 2.2 Tankers carrying flammable liquefied gases...................................... 149 2.3 Electrical installations in cargo area and adjacent to this area............. 150 3 Inspection and testing.....................................................................151 3.1 General requirements.................................................................... 151 4 Maintenance.....................................................................................151 4.1 General requirements.................................................................... 151 Section 11 Fire protection and extinction........................................................... 152 1 Fire safety requirements..................................................................152 1.1 General requirements.................................................................... 152 2 Fire mains and hydrants.................................................................. 152 2.1 General requirements.................................................................... 152 3 Water spray system.........................................................................153

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 10

Part 5 Chapter 7 Contents

4 Sizing of pressure relieving system................................................. 137

4 Dry chemical powder fire-extinguishing systems.............................155 4.1 General requirements.................................................................... 155 5 Enclosed spaces containing cargo handling equipment.................... 156 5.1 General requirements.................................................................... 156 6 Firefighters' outfits.......................................................................... 156 6.1 General requirements.................................................................... 156 Section 12 Artificial ventilation in cargo area..................................................... 157 1 Spaces required to be entered during normal handling operations...157 1.1 General requirements.................................................................... 157 2 Spaces not normally entered........................................................... 158 2.1 General requirements.................................................................... 158 3 Ventilation arrangement and capacity requirements....................... 158 3.1 General requirements.................................................................... 158 3.2 Non-hazardous spaces................................................................... 159 Section 13 Instrumentation and automation.......................................................161 1 General............................................................................................ 161 1.1 General requirements.................................................................... 161 2 Level indicators for cargo tanks...................................................... 161 2.1 General requirements.................................................................... 161 3 Overflow control.............................................................................. 162 3.1 General requirements.................................................................... 162 4 Pressure monitoring........................................................................ 163 4.1 General requirements.................................................................... 163 5 Temperature indicating devices....................................................... 163 5.1 General requirements.................................................................... 163 6 Gas detection................................................................................... 164 6.1 General requirements.................................................................... 164 7 Additional requirements for containment systems requiring a secondary barrier............................................................................... 166 7.1 Integrity of barriers.......................................................................166 7.2 Temperature indication devices....................................................... 166 8 Automation systems........................................................................ 166 8.1 General requirements.................................................................... 166 9 System integration.......................................................................... 167 9.1 General requirements.................................................................... 167 10 Hold leakage alarm........................................................................ 168 10.1 General requirements.................................................................. 168

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 11

Part 5 Chapter 7 Contents

3.1 General requirements.................................................................... 153

11.1 General requirements.................................................................. 168 12 Monitoring of re-liquefaction plants...............................................170 12.1 General requirements.................................................................. 170 12.2 Re-liquefaction system (Brayton cycle) for methane (LNG)................ 171 13 Monitoring of inert gas generator..................................................171 13.1 General requirements.................................................................. 171 14 Monitoring of nitrogen generator...................................................172 14.1 General arrangement................................................................... 172 15 Guidance on alarm and shut down................................................ 173 15.1 General arrangement................................................................... 173 Section 14 Personnel protection......................................................................... 177 1 General requirements for all products............................................. 177 1.1 Protective equipment..................................................................... 177 1.2 First-aid equipment....................................................................... 177 1.3 Safety equipment..........................................................................177 2 Personal protection requirements for individual products................178 2.1 General requirements.................................................................... 178 Section 15 Filling limit of cargo tanks................................................................ 179 1 General............................................................................................ 179 1.1 Definitions.................................................................................... 179 1.2 General requirements.................................................................... 179 1.3 Default filling limit.........................................................................179 1.4 Determination of increased filling limit............................................. 179 1.5 Maximum loading limit...................................................................180 2 Information to be provided to the master....................................... 180 2.1 Documentation............................................................................ 180 Section 16 Use of gas fuel.................................................................................. 181 1 General............................................................................................ 181 1.1 Requirements................................................................................181 2 Use of cargo vapour as fuel.............................................................181 2.1 General requirements.................................................................... 181 3 Arrangement of spaces containing gas consumers.......................... 181 3.1 General requirements.................................................................... 181 4 Gas fuel supply................................................................................ 182 4.1 General requirements.................................................................... 182 4.2 Leak detection.............................................................................. 182

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 12

Part 5 Chapter 7 Contents

11 Monitoring of thermal oxidation vapour systems........................... 168

4.4 Requirements for gas fuel with pressure greater than 1 MPa............... 182 4.5 Gas consumer isolation.................................................................. 183 4.6 Spaces containing gas consumers................................................... 183 4.7 Piping and ducting construction...................................................... 183 4.8 Gas detection............................................................................... 184 5 Gas fuel plant and related storage tanks......................................... 184 5.1 Provision of gas fuel......................................................................184 5.2 Remote stops and alarm................................................................ 184 5.3 Heating and cooling mediums.........................................................184 5.4 Piping and pressure vessels............................................................184 6 Special requirements for main boilers............................................. 184 6.1 Arrangements............................................................................... 184 6.2 Combustion equipment.................................................................. 185 6.3 Safety..........................................................................................185 7 Special requirements for gas-fired internal combustion engines...... 186 7.1 Arrangements............................................................................... 186 7.2 Combustion equipment.................................................................. 186 7.3 Safety..........................................................................................186 8 Special requirements for gas turbine...............................................187 8.1 Arrangements............................................................................... 187 8.2 Combustion equipment.................................................................. 187 8.3 Safety..........................................................................................187 9 Alternative fuels and technologies...................................................187 9.1 General requirements.................................................................... 187 10 Gas only installations.....................................................................188 10.1 General requirements and safety...................................................188 11 Gas fuel operation manual.............................................................188 11.1 General requirements.................................................................. 188 Section 17 Special requirements......................................................................... 189 1 General............................................................................................ 189 1.1 Materials of construction................................................................ 189 1.2 Independent tanks........................................................................ 189 1.3 Refrigeration systems.................................................................... 189 1.4 Cargoes requiring type 1G ship.......................................................190 1.5 Exclusion of air from vapour spaces................................................ 190 1.6 Moisture control............................................................................ 190 1.7 Inhibition..................................................................................... 190

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 13

Part 5 Chapter 7 Contents

4.3 Routeing of fuel supply pipes......................................................... 182

1.9 Maximum allowable quantity of cargo per tank................................. 191 1.10 Cargo pumps and discharge arrangements..................................... 191 2 Ammonia..........................................................................................191 2.1 General requirements.................................................................... 191 3 Chlorine........................................................................................... 192 3.1 Cargo containment system............................................................. 192 3.2 Cargo piping systems.................................................................... 193 3.3 Materials...................................................................................... 193 3.4 Instrumentation, safety devices...................................................... 193 3.5 Personnel protection...................................................................... 194 3.6 Filling limits for cargo tanks........................................................... 194 4 Ethylene oxide................................................................................. 194 4.1 General requirements.................................................................... 194 5 Separate piping systems..................................................................195 5.1 General........................................................................................ 195 6 Methyl acetylene-propadiene mixtures............................................ 195 6.1 General requirements.................................................................... 195 7 Nitrogen........................................................................................... 196 7.1 General requirements.................................................................... 196 8 Propylene oxide and mixtures of ethylene oxide-propylene oxide with ethylene oxide content of not more than 30% by weight............196 8.1 General requirements.................................................................... 196 9 Vinyl chloride................................................................................... 199 9.1 General requirements.................................................................... 199 10 Mixed C4 cargoes...........................................................................199 10.1 General requirements.................................................................. 199 11 Carbon dioxide............................................................................... 199 11.1 Carbon dioxide – high purity........................................................ 199 11.2 Carbon dioxide – reclaimed quality................................................ 200 Section 18 Cargo operation manual and cargo emergency shutdown system......201 1 Cargo operations manuals............................................................... 201 1.1 General requirements.................................................................... 201 1.2 Cargo information......................................................................... 201 2 Cargo emergency shutdown (ESD) system...................................... 202 2.1 General........................................................................................ 202 2.2 ESD valve requirements.................................................................202 2.3 ESD system controls..................................................................... 203

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 14

Part 5 Chapter 7 Contents

1.8 Flame screens on vent outlets........................................................ 191

Section 19 Summary of minimum requirements................................................. 207 1 General............................................................................................ 207 1.1 Explanatory notes to the summary of minimum requirements............. 207 Section 20 Design with independent prismatic tanks of type-A and type-B......... 212 1 Type-A tank..................................................................................... 212 1.1 Design basis................................................................................. 212 1.2 Structural analysis of cargo tanks................................................... 212 1.3 Ultimate design condition............................................................... 213 1.4 Accident design condition............................................................... 213 1.5 Testing......................................................................................... 214 1.6 Special consideration for single side hull.......................................... 214 2 Type-B tank..................................................................................... 214 2.1 Design basis................................................................................. 214 2.2 Structural analysis of cargo tanks................................................... 215 2.3 Ultimate design condition............................................................... 216 2.4 Fatigue design condition................................................................ 216 2.5 Accident design condition............................................................... 216 2.6 Testing......................................................................................... 216 3 Local strength of cargo tanks.......................................................... 217 3.1 Internal pressure in cargo tanks..................................................... 217 3.2 Requirements for local scantlings.................................................... 217 4 Cargo tank and hull finite element analysis..................................... 219 4.1 General........................................................................................ 219 4.2 Loading conditions and design load cases.........................................220 4.3 Acceptance criteria for cargo hold finite element analysis................... 221 5 Local structural strength analysis....................................................223 5.1 General........................................................................................ 223 5.2 Locations to be checked.................................................................223 5.3 Fine mesh FE models.................................................................... 224 5.4 Acceptance criteria........................................................................ 224 5.5 Acceptance criteria for wood, resin and dam plates........................... 224 6 Thermal analysis..............................................................................225 6.1 General........................................................................................ 225 6.2 Thermal stress analysis................................................................. 225 6.3 Acceptance criteria........................................................................ 226 7 Sloshing assessment........................................................................226

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 15

Part 5 Chapter 7 Contents

2.4 Additional shutdowns.....................................................................205

7.2 Sloshing strength analysis..............................................................226 8 Fatigue analysis............................................................................... 226 8.1 General........................................................................................ 226 8.2 Locations to be considered............................................................. 227 8.3 Loading conditions.........................................................................227 8.4 Load cases................................................................................... 228 8.5 Acceptance criteria........................................................................ 228 9 Crack propagation analysis.............................................................. 229 9.1 General........................................................................................ 229 9.2 Initial defects to be used............................................................... 230 9.3 Acceptance criteria........................................................................ 230 9.4 Leak rates.................................................................................... 230 10 Vibration analysis.......................................................................... 230 10.1 Requirements..............................................................................230 Section 21 Design with spherical independent tanks of type-B........................... 231 1 General............................................................................................ 231 1.1 Design basis................................................................................. 231 1.2 Spherical cargo tank system.......................................................... 231 1.3 Structural analysis of cargo tanks................................................... 232 2 Cargo tank and hull finite element analysis..................................... 233 2.1 General........................................................................................ 233 2.2 Loading conditions and design load cases.........................................234 3 Acceptance criteria – hull and cargo tanks...................................... 234 3.1 Ultimate limit state design condition - hull....................................... 234 3.2 Ultimate limit state design condition - cargo tanks............................ 235 3.3 Fatigue limit state design condition - cargo tanks.............................. 236 3.4 Accident design condition - cargo tanks........................................... 237 3.5 Acceptance levels for vibration response.......................................... 238 4 Thermal analysis..............................................................................238 4.1 Temperature analysis.....................................................................238 4.2 Acceptance criteria........................................................................ 238 5 Sloshing........................................................................................... 238 5.1 Sloshing loads.............................................................................. 238 6 Testing............................................................................................. 239 6.1 Requirements................................................................................239 Section 22 Design with cylindrical tanks of type-C............................................. 240

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 16

Part 5 Chapter 7 Contents

7.1 General........................................................................................ 226

1.1 Design basis................................................................................. 240 1.2 Design loads.................................................................................240 2 Ultimate strength assessment of cargo tanks.................................. 243 2.1 General requirement......................................................................243 2.2 Design conditions.......................................................................... 244 2.3 Scantling due to internal pressure...................................................245 2.4 Scantling due to external pressure.................................................. 246 2.5 Supports...................................................................................... 248 2.6 Swash bulkheads.......................................................................... 249 2.7 Openings and their reinforcement................................................... 249 2.8 Acceptance criteria........................................................................ 250 3 Cargo tank and hull finite element analysis..................................... 252 3.1 General........................................................................................ 252 3.2 Loading conditions and design load cases.........................................252 3.3 Acceptance criteria for cargo hold finite element analysis................... 253 4 Local structure strength analysis.....................................................253 4.1 General........................................................................................ 253 4.2 Locations to be checked.................................................................253 4.3 Acceptance criteria........................................................................ 254 5 Fatigue strength assessment........................................................... 254 5.1 Hull structure............................................................................... 254 5.2 Fatigue of cargo tanks................................................................... 254 6 Accidental strength assessment...................................................... 255 6.1 General........................................................................................ 255 7 Testing............................................................................................. 255 7.1 Requirements................................................................................255 8 Manufacture and workmanship........................................................256 8.1 General........................................................................................ 256 8.2 Stress relieving............................................................................. 256 8.3 Manufacture................................................................................. 257 8.4 Marking........................................................................................258 Section 23 Design with membrane tanks............................................................ 259 1 General............................................................................................ 259 1.1 Design basis................................................................................. 259 1.2 Design considerations.................................................................... 259 1.3 Arrangement of cargo area............................................................ 260 1.4 Loads...........................................................................................261

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 17

Part 5 Chapter 7 Contents

1 General............................................................................................ 240

2 Ultimate strength assessment......................................................... 262 2.1 General........................................................................................ 262 2.2 Local scantling of inner hull............................................................262 3 Finite element strength analysis for hull......................................... 265 3.1 Cargo hold analysis....................................................................... 265 3.2 Local fine mesh analysis................................................................ 265 4 Fatigue strength assessment......................................................... 265 4.1 General........................................................................................ 265 4.2 Fatigue assessment for hull............................................................ 266 4.3 Fatigue evaluation of membrane system.......................................... 266 5 Accidental strength assessment...................................................... 267 5.1 General........................................................................................ 267 6 Testing............................................................................................. 267 6.1 Design development testing........................................................... 267 6.2 Testing for newbuilding.................................................................. 267 Section 24 Other cargo tank designs.................................................................. 268 1 Integral tanks.................................................................................. 268 1.1 Design basis................................................................................. 268 1.2 Structural analysis.........................................................................268 1.3 Testing......................................................................................... 268 2 Semi-membrane tanks..................................................................... 269 2.1 Design basis................................................................................. 269 3 Cargo containment systems of novel configuration......................... 269 3.1 Limit state design for novel concepts...............................................269 Appendix A Non-metallic materials..................................................................... 271 1 General............................................................................................ 271 1.1 Introduction..................................................................................271 2 Material selection criteria................................................................ 271 2.1 Non-metallic materials................................................................... 271 3 Property of materials.......................................................................271 3.1 General........................................................................................ 271 4 Material selection and testing requirements.................................... 272 4.1 Material specification..................................................................... 272 4.2 Material testing............................................................................. 272 5 Quality assurance and quality control (QA/QC)............................... 274 5.1 General........................................................................................ 274

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 18

Part 5 Chapter 7 Contents

1.5 Structural analysis.........................................................................262

6 Bonding and joining process requirement and testing..................... 275 6.1 Bonding procedure qualification...................................................... 275 6.2 Personnel qualifications.................................................................. 276 7 Production bonding tests and controls............................................ 276 7.1 Destructive testing........................................................................ 276 7.2 Non-destructive testing.................................................................. 276 Appendix B Standard for the use of limit state methodologies in the design of cargo containment systems of novel configuration.............................................277 1 General............................................................................................ 277 1.1 Introduction..................................................................................277 2 Design format.................................................................................. 277 2.1 Design procedure.......................................................................... 277 3 Required analyses............................................................................279 3.1 General........................................................................................ 279 4 Ultimate limit state..........................................................................279 4.1 Design procedure for ULS design.................................................... 279 5 Fatigue limit states.......................................................................... 283 5.1 Design procedure for FLS design.....................................................283 6 Accident limit states........................................................................ 284 6.1 Design procedure for ALS.............................................................. 284 7 Testing............................................................................................. 284 7.1 Testing requirements..................................................................... 284 Changes – historic.............................................................................................. 285

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 19

Part 5 Chapter 7 Contents

5.2 QA/QC during component manufacture............................................ 275

1 Introduction 1.1 Introduction 1.1.1 This chapter provides rules for ships intended for carriage of the liquefied gases.

1.2 Scope 1.2.1 The scope of this chapter includes requirements applicable to tankers for liquefied gas, regardless of size.

1.3 Application 1.3.1 The requirements in this chapter are considered to meet the requirements of the international code for the construction and equipment of ships carrying liquefied gases in bulk, IGC code, Res. MSC.370(93). 1.3.2 The requirements in this chapter are supplementary to those for assignment of main class. The additional hazards considered in this chapter include fire, toxicity, corrosivity, reactivity, low temperature and pressure. 1.3.3 Machinery installations and their auxiliary systems that support cargo handling, shall meet the same rule requirements as if they were considered to support a main function, see Pt.1 Ch.1 Sec.1. 1.3.4 List of products The list of products in Sec.19 gives a summary of minimum requirements for each individual product. This list will be supplemented and adjusted by the Society as found necessary.

1.4 Class notations 1.4.1 Ship type notation The class notations specified in Table 1 are normally applicable for transport of liquefied gas cargo. Table 1 Ship type notations Class notation

Description

Applications

Tanker for liquefied gas

Ships designed for transportation of liquefied gas.

Tanker for C

Tanker for c, where c indicates Mandatory for ships dedicated the name or group of for transport of specific product(s) for which the ship is product(s) as in Sec.19. classified.

Mandatory for ships that shall transport products given in Sec.19.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Design requirements, rule reference This chapter. Tanker for C will be considered in each case, depending on the nature of the cargo to be carried based on requirements given in this chapter.

Page 20

Part 5 Chapter 7 Section 1

SECTION 1 GENERAL REQUIREMENTS

Design requirements, rule reference

Description

Applications

Barge for liquefied gas

Barge designed for transportation of liquefied gas.

Mandatory for barges that shall transport products given in Sec.19.

Ch.11 and this chapter.

Barge for C

Barge for c, where c indicates the name or group of product(s) for which the barge is classified.

Mandatory for barges dedicated for transport of specific product(s) as in Sec.19.

Barge for C will be considered in each case, depending on the nature of the cargo to be carried based on requirements given in this chapter and Ch.11.

1.4.2 Additional notations The following additional notations, as specified in Table 2, may be applicable. The following notations are particularly connected to liquefied gas cargo. Table 2 Additional class notations Class notations

Description

Applications

Design requirements, rule reference

REGAS

Ships designed for regasification operations.

All ships with regasification plant installed.

Pt.6 Ch.4 Sec.8

Gas bunker

Ships designed for gas bunker operations.

Alls ships.

Pt.6 Ch.5 Sec.14

Plus

Extended fatigue analysis of ship details.

All ships.

Pt.6 Ch.1 Sec.6

CSA

Direct analysis of ship structures

All ships.

Pt.6 Ch.1 Sec.7

For full definition of all additional class notations, see Pt.1 Ch.2. 1.4.3 Register information Special features notations provide information regarding special features of the ship and will be stated in the register of vessels classed with the Society. The register information specified in Table 3 is normally applicable for transport of liquefied gas cargo and give details on ship cargo transport compatibility. Table 3 Register information

Technical features

Register information

Design requirements, rule reference

Description

ship type 1G Ship type

ship type 2G ship type 2PG

The damage stability standard in accordance with IMO’s international gas carrier code.

Sec.2 [1]

ship type 3G Design parameters (specified in brackets)

temperature °C density kg/m

3

The minimum and/or maximum acceptable temperature in the tank in °C. 3

The maximum acceptable cargo density in kg/m .

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 21

Part 5 Chapter 7 Section 1

Class notation

Fuel type

Register information

Description

pressure MPa

Maximum allowable relief valve setting, MARVS in MPa.

GF

Gas fuelled according to the requirements given in this rule chapter.

Design requirements, rule reference

Sec.16

Guidance note: A ship with class notation Tanker for liquefied gas and the following data may be recorded in the register of vessels classed with 3

the Society: Ship type 2G (-163°C, 500 kg/m , 0.025 MPa) GF which means that the ship is a type 2G ship according to IMO’s international gas carrier code, the lowest acceptable tank temperature is -163°C, maximum acceptable density of the cargo is 500 3

kg/m , MARVS is 0.025 MPa and gas fuelled. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2 General 2.1 General 2.1.1 When cargo tanks contain products for which the chapter requires a type 1G ship, neither flammable liquids having a flashpoint of 60°C (closed cup test) or less, nor flammable products listed in Sec.19, shall be carried in tanks located within the protective zones described in Sec.2 [4.1.1]. 2.1.2 Similarly, when cargo tanks contain products for which the chapter requires a type 2G/2PG ship, the flammable liquids as described in [2.1.1], shall not be carried in tanks located within the protective zones described in Sec.2 [4.1.2]. 2.1.3 In each case, for cargo tanks loaded with products for which the chapter requires a type 1G or 2G/2PG ship, the restriction applies to the protective zones within the longitudinal extent of the hold spaces for those tanks. 2.1.4 The flammable liquids and products described in [2.1.1] may be carried within these protective zones when the quantity of products retained in the cargo tanks, for which the chapter requires a type 1G or 2G/2PG ship, is solely used for cooling, circulation or fuelling purposes. 2.1.5 When a ship is intended to operate for periods at a fixed location in a re-gasification and gas discharge mode or a gas receiving, processing, liquefaction and storage mode, the flag administration and port administrations involved in the operation shall take appropriate steps to ensure implementation of the provisions of this chapter as are applicable to the proposed arrangements. Furthermore, additional requirements shall be established based on the principles of this chapter as well as recognized standards that address specific risks not envisaged by it. Such risks may include, but not be limited to: 1) 2) 3) 4) 5) 6) 7) 8) 9)

fire and explosion evacuation extension of hazardous areas pressurized gas discharge to shore high-pressure gas venting process upset conditions storage and handling of flammable refrigerants continuous presence of liquid and vapour cargo outside the cargo containment system tank over-pressure and under-pressure

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 22

Part 5 Chapter 7 Section 1

Technical features

Guidance note: Additional requirements to regasification vessels are given in Pt.6 Ch.4 Sec.8. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.6 Where a risk assessment or study of similar intent is utilized within these rules, the results shall also include, but not be limited to, the following as evidence of effectiveness: 1) 2) 3) 4) 5) 6) 7) 8)

description of methodology and standards applied potential variation in scenario interpretation or sources of error in the study validation of the risk assessment process by an independent and suitable third party quality system under which the risk assessment was developed the source, suitability and validity of data used within the assessment the knowledge base of persons involved within the assessment system of distribution of results to relevant parties validation of results by an independent and suitable third party.

2.2 Tank types 2.2.1 Design basis together with reference to the respective rule parts are given in Table 4. Table 4 Tank type characteristics Tank type Integral tanks

Membrane tanks

Characteristics Integral tanks form a part of the ship’s hull and are influenced by the hull load. Membrane tanks consist of a thin membrane(s) supported through insulation by the adjacent hull structure. Thermal and other expansion or contraction is compensated for without undue risk of losing the tightness of the membrane.

Design requirements, rule reference Sec.24 [1] (integral tanks) Sec.23 (membrane tanks)

Semi-membrane tanks

Semi-membrane tanks consist of a layer, partly supported through insulation by the adjacent hull structure, whereas rounded parts of the layer connecting the supported parts are designed to accommodate thermal and other expansion or contraction

Independent tanks

Do not form part of the ship hull and is designed to minimise interaction forces on the tanks from hull deflection.

Type A

Primarily designed using classical ship-structural analysis procedures in accordance with recognized standards.

Sec.20 (prismatic tanks)

Type B

Designed using model tests, refined analytical tools and analysis methods to determine stress levels, fatigue life and crack propagation characteristics.

Sec.20 (prismatic tanks) or Sec.21 (spherical tanks)

Type C

Pressure vessel design with a minimum design pressure P0 is defined to ensure that stresses are predominantly of membrane type, and dynamic stresses are sufficiently low.

Sec.22 (cylindrical tanks)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Sec.24 [2] (semimembrane tanks)

Page 23

Part 5 Chapter 7 Section 1

10) ship-to-ship transfer of liquid cargo 11) collision risk during berthing manoeuvres.

3.1 Terms Table 5 Definitions of terms Terms

Definition

A class divisions

divisions as defined in regulation II-2/3.2 of the SOLAS convention

accommodation spaces

spaces used for public spaces, corridors, lavatories, cabins, offices, hospitals, cinemas, games and hobby rooms, barber shops, pantries without cooking appliances and similar spaces

air lock

enclosed space for entrance between a hazardous area on open deck and a non-hazardous space, arranged to prevent ingress of gas to the non-hazardous space

anniversary date

day and month of each year that will correspond to the date of expiry of the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk

boiling point

temperature at which a product exhibits a vapour pressure equal to the atmospheric pressure

breadth, B

maximum breadth of the ship, measured amidships to the moulded line of the frame in a ship with a metal shell, and to the outer surface of the hull in a ship with a shell of any other material The breadth, B, shall be measured in metres, see also Pt.3 Ch.1 Sec.4 [2].

cargo area

part of the ship which contains the cargo containment system and cargo pump and compressor rooms and includes the deck areas over the full length and breadth of the part of the ship over these spaces Where fitted, the cofferdams, ballast or void spaces at the after end of the aftermost hold space or at the forward end of the foremost hold space are excluded from the cargo area.

cargo containment system

arrangement for containment of cargo including, where fitted, a primary and secondary barrier, associated insulation and any intervening spaces, and adjacent structure, if necessary, for the support of these elements If the secondary barrier is part of the hull structure, it may be a boundary of the hold space.

cargo control room

space used in the control of cargo handling operations and complying with the requirements of Sec.3 [4.1]

cargo machinery spaces

spaces where cargo compressors or pumps, cargo processing units, are located, including those supplying gas fuel to the engine-room

cargo process pressure vessels

process pressure vessels in the cargo handling plant, which during normal operations will contain cargo in the liquid and or gaseous phase See Sec.5 [1.1.3] and Sec.5 [13.6].

cargo pumps

pumps used for the transfer of liquid cargo including main pumps, booster pumps, spray pumps, etc.

cargo service spaces

spaces within the cargo area, used for workshops, lockers and store-rooms that are of more 2 than 2 m in area

cargo tank

liquid-tight shell designed to be the primary container of the cargo and includes all such containment systems whether or not they are associated with the insulation or/and the secondary barriers

cargoes

products listed in Sec.19 that are carried in bulk by ships subject to this chapter

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 24

Part 5 Chapter 7 Section 1

3 Definitions

Definition

closed loop sampling

cargo sampling system that minimizes the escape of cargo vapour to the atmosphere by returning product to the cargo tank during sampling

cofferdam

isolating space between two adjacent steel bulkheads or decks This space may be a void space or a ballast space.

control station

spaces in which ship’s radio, main navigating equipment or the emergency source of power is located or where the fire-recording or fire control equipment is centralized This does not include special fire control equipment, which can be most practically located in the cargo area.

design pressure P0 for cargo piping

pressure used to determine minimum scantlings of piping and piping system components See Sec.5.

design temperature for cargo piping

minimum temperature that can occur in cargo process pressure vessels and all associated systems and components, during cargo handling operations

design temperature for cargo tanks

minimum temperature at which cargo may be loaded or transported in the cargo tanks This temperature normally reflects the boiling point (see definition of boiling point) of the cargo transported. Only on case by case basis a higher temperature corresponding to increased pressure should be considered.

design temperature for secondary barrier

complete or partial secondary barrier is equal to the boiling point of the most volatile cargo

flammable products

products identified by an F in column f in the table of Sec.19

flammability limits

conditions defining the state of fuel-oxidant mixture at which application of an adequately strong external ignition source is only just capable of producing flammability in a given test apparatus

FSS code

fire safety systems code meaning the international code for fire safety systems, adopted by the maritime safety committee of the organization by resolution MSC.98(73)

gas carrier

cargo ship constructed or adapted and used for the carriage in bulk of any liquefied gas or other products listed in the table of Sec.19

gas combustion unit (GCU)

means of disposing excess cargo vapour by thermal oxidation

gas consumer

unit within the ship using cargo vapour as a fuel

gauging device

arrangement for determining the amount of cargo in tanks See Sec.13 [2.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 25

Part 5 Chapter 7 Section 1

Terms

hazardous area

Definition area in which an explosive gas atmosphere is, or may be expected to be present, in quantities that require special precautions for the construction, installation and use of electrical equipment When a gas atmosphere is present, the following hazards may also be present: toxicity, asphyxiation, corrosivity, reactivity and low temperature. These hazards shall also be taken into account and additional precautions for the ventilation of spaces and protection of the crew will need to be considered. Examples of hazardous areas include, but are not limited to, the following with detailed requirements given in Sec.10:

.1

the interiors of cargo containment systems and any pipework of pressure-relief or other venting systems for cargo tanks, pipes and equipment containing the cargo

.2 .3 .4

interbarrier spaces

.5

a space separated from a hold space by a single gastight steel boundary where the cargo containment system requires a secondary barrier space separated from a hold space by a single gastight steel boundary where the cargo containment system requires a secondary barrier

.6 .7

cargo machinery spaces

.8

areas on open deck or semi-enclosed spaces on open deck within 1.5 m of cargo machinery space entrances, cargo machinery space ventilation inlets

.9

areas on open deck over the cargo area and 3 m forward and aft of the cargo area on the open deck up to a height of 2.4 m above the weather deck

.10

an area within 2.4 m of the outer surface of a cargo containment system where such surface is exposed to the weather area within 2.4 m of the outer surface of a cargo containment system where such surface is exposed to the weather

.11

enclosed or semi-enclosed spaces in which pipes containing cargoes are located, except those where pipes containing cargo products for boil-off gas fuel burning systems are located

.12

an enclosed or semi-enclosed space having a direct opening into any hazardous area enclosed or semi-enclosed space having a direct opening into any hazardous area

.13

void spaces, cofferdams, trunks, passageways and enclosed or semi-enclosed spaces, adjacent to, or immediately above or below, the cargo containment system

.14

areas on open deck or semi-enclosed spaces on open deck above and in the vicinity of any vent riser outlet, within a vertical cylinder of unlimited height and 6 m radius centred upon the centre of the outlet and within a hemisphere of 6 m radius below the outlet, and

.15

areas on open deck within spillage containment surrounding cargo manifold valves and 3 m beyond these up to a height of 2.4 m above deck

hold spaces where the cargo containment system requires a secondary barrier hold spaces where the cargo containment system does not require a secondary barrier

areas on open deck, or semi-enclosed spaces on open deck, within 3 m of possible sources of gas release, such as cargo valve, cargo pipe flange, cargo machinery space ventilation outlet, etc.

Guidance note: The definition of hazardous area is only related to the risk of explosion. In this context, health, safety and environmental issues, i.e. toxicity is not considered. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 26

Part 5 Chapter 7 Section 1

Terms

Definition

hold space

space enclosed by the ship’s structure in which a cargo containment system is situated

IBC code

international code for the construction and equipment of ships carrying dangerous chemicals in bulk, adopted by the maritime safety committee of the organization by resolution MSC.4(48), as amended

independent system

means that a piping or venting system, for example, is in no way connected to another system and that there are no provisions available for the potential connection to other systems

insulation space

space, which may or may not be an interbarrier space, occupied wholly or in part by insulation

length, LLL

freeboard length as defined in the international convention on load lines in force See also Pt.3 Ch.1 Sec.4 [2].

liquefied gas

cargo with a vapour pressure equal to or above 0.28 MPa absolute at 37.8°C

machinery space

machinery spaces of category A and other spaces containing propelling machinery, boilers, oil fuel units, steam and internal-combustion engines, generators and major electrical machinery, oil filling stations, refrigerating, stabilizing, ventilation and air-conditioning machinery, and similar spaces and the trunks to such spaces

machinery spaces of category A

spaces, and trunks to those spaces, which contain at least one fo the following: internal combustion machinery used for main propulsion, or .1

.2

internal combustion machinery used for purposes other than main propulsion where such machinery has, in the aggregate, a total power output of not less than 375 kW, or

.3

any oil-fired boiler or oil fuel unit or any oil-fired equipment other than boilers, such as inert gas generators, incinerators, etc.

MARVS

maximum allowable relief valve setting of a cargo tank (gauge pressure)

nominated surveyor

surveyor nominated/appointed by an administration to enforce the provisions of the SOLAS convention regulations with regard to inspections and surveys and the granting of exemptions therefrom

non-cargo process pressure vessels

process pressure vessels in the cargo handling plant which during normal operations will not contain cargo Non-cargo process pressure vessels generally contain refrigerants of the halogenated hydrocarbon type in the liquid and or gaseous phase. Non-cargo process pressure vessels shall meet the requirements to scantlings, manufacture, workmanship, inspection and testing, and material selection as for pressure vessels as given in Pt.4 Ch.7.

non-hazardous area

area other than a hazardous area, i.e. gas safe

oil fuel unit

equipment used for the preparation of oil fuel for delivery to an oil-fired boiler, or equipment used for the preparation for delivery of heated oil to an internal combustion engine, and includes any oil pressure pumps, filters and heaters dealing with oil at a pressure of more than 0.18 MPa gauge

organization

International Maritime Organization (IMO)

permeability of a space

ratio of the volume within a space which is assumed to be occupied by water to the total volume of that space

port administration

appropriate authority of the country for the port where the ship is loading or unloading

pressure relief valves (PRV)

safety valve which opens at a given internal pressure above atmospheric pressure See Sec.8.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 27

Part 5 Chapter 7 Section 1

Terms

Definition

primary barrier

inner element designed to contain the cargo when the cargo containment system includes two boundaries

products

any of the gases listed in Sec.19

public spaces

portions of the accommodation that are used for halls, dining rooms, lounges and similar permanently enclosed spaces

recognized organization

organization authorized by an administration in accordance with SOLAS regulation XI-1/1 to act on its behalf Guidance note: The Society is the recognized organization for the IGC code. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

recognized standards

applicable international or national standards acceptable to the administration, or standards laid down and maintained by the recognized organization Guidance note: A recognized standard is either the rules itself (as recognised by the flag adm by authorization), or it is a standard to be recognised by the Society. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

relative density

ratio of the mass of a volume of a product to the mass of an equal volume of fresh water

secondary barrier

liquid-resisting outer element of a cargo containment system, designed to afford temporary containment of any envisaged leakage of liquid cargo through the primary barrier and to prevent the lowering of the temperature of the ship’s structure to an unsafe level Types of secondary barrier are more fully defined in Sec.4.

separate systems

cargo piping and vent systems that are not permanently connected to each other Guidance note: The required piping separation should be accomplished by the removal of spool pieces, valves, or other pipe sections and the installation of blank flanges at these locations. The required separation applies to all liquid and vapour piping, liquid and vapour vent lines and any other possible connections such as common inert gas supply lines. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

service spaces

spaces used for galleys, pantries containing cooking appliances, lockers, mail and specie rooms, store-rooms, workshops other than those forming part of the machinery spaces, and similar spaces and trunks to such spaces

SOLAS convention

international convention for the safety of life at sea, 1974, as amended

spaces not normally entered

cofferdams, double bottoms, duct keels, pipe tunnels, stool tanks, spaces containing cargo tanks and other spaces where cargo may accumulate See Sec.12 [2].

steel significant temperature

calculated temperature in the hull structures, tank fundaments and tank supports when the cargo containment systems and the cargo piping systems are at the design temperature and the ambient temperatures are the design ambient temperatures See Sec.4 [5.1.1] and Sec.4 [5.1.2].

tank cover

protective structure intended to either protect the cargo containment system against damage where it protrudes through the weather deck or to ensure the continuity and integrity of the deck structure

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 28

Part 5 Chapter 7 Section 1

Terms

Definition

tank dome

upward extension of a portion of a cargo tank. In the case of below-deck cargo containment systems, the tank dome protrudes through the weather deck or through a tank cover

thermal oxidation

system where the boil-off vapours are utilized as fuel for shipboard use or as a waste heat system subject to the provisions of Sec.16 or a system not using the gas as fuel complying with this chapter

toxic products

products defined by a T in column f in the table of Sec.19

turret compartments

spaces and trunks that contain equipment and machinery for retrieval and release of the disconnectable turret mooring system, high-pressure hydraulic operating systems, fire protection arrangements and cargo transfer valves

vacuum relief valve

safety valve which opens at a given internal pressure below atmospheric pressure By P/V valves are meant combined pressure/vacuum See Sec.8.

vapour pressure

equilibrium pressure of the saturated vapour above the liquid, expressed in pascal (Pa) absolute at a specified temperature

void space

enclosed space in the cargo area external to a cargo containment system, other than a hold space, ballast space, oil fuel tank, cargo pumps or compressor room, or any space in normal use by personnel

3.2 Symbols For symbols not defined in this chapter, see Pt.3 Ch.1 Sec.4.

TMIN TDAM h Rm

= min. relevant seagoing draught in m

ReH

= the specified minimum upper yield stress at room temperature in N/mm . If the stress-strain curve does not show a defined yield stress, the 0.2% proof stress applies, see also Sec.4 [4.3.2].

ReH,0.2

= the specified minimum 0.2% proof stress at room temperature in N/mm . For welded connections in aluminium alloys the 0.2% proof stress in annealed condition shall be used, see also Sec.4 [4.3.2].

LT UDW

= material grade intended for low temperature service.

FDW

= fatigue design wave determined by direct hydrodynamic wave load analysis. The FDW returns -2 the same long term load level as spectral analysis and corresponds to a probability level 10 in North Atlantic wave environment.

= damaged draught from damage stability calculation in m = usage factor

2

= the specified minimum tensile strength at room temperature in N/mm . For welded connections in aluminium alloys the tensile strength in annealed condition shall be used, see also Sec.4 [4.3.2]. 2

2

= ultimate design wave determined by direct hydrodynamic wave load analysis. The UDW returns -8 the same long term load level as spectral analysis and corresponds to a probability level 10 in North Atlantic wave environment.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 29

Part 5 Chapter 7 Section 1

Terms

4.1 Documentation requirements Documentation shall be submitted as required by Table 6. Table 6 Documentation requirements - Liquefied gas tankers Object

Damage stability

Documentation type

Additional description

Info

B130 – Final damage stability calculation

AP

B070 – Preliminary damage stability calculation

AP

I200 - Control and monitoring system documentation

AP

S010 – Piping diagram (PD)

From master gas valve in cargo area to consumer, including vent arrangement.

AP

Z100 – Specification

Details of installation for preparations of gas before combustion.

FI

Z060 – Functional description

Applicable for novel gas fuel designs or for ships with gas only installation.

FI

Z030 – Arrangement plan

Gas piping, gas-tight boiler casing with funnel, ventilation, gas valve train and other items necessary for the fuel gas handling.

AP

G130 – Cause and effect diagram

Including all items that gives alarm and automatic shutdown.

AP

Bilge water control and monitoring system

Z030 – Arrangement plan

Sensors in hold spaces and secondary insulation spaces.

AP

Hazardous areas classification

G080 – Hazardous area classification drawing

Fuel gas system

AP

E170 – Electrical schematic drawing

Single line diagrams for all intrinsically safe circuits, for each circuit including data for verification of the compatibility between the barrier and the field components.

AP

Z030 – Arrangement plan

Electrical equipment in hazardous areas. Where relevant, based on an approved hazardous area classification drawing where location of electric equipment in hazardous area is added (except battery room, paint stores and gas bottle store).

AP

Explosion (Ex) protection

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 30

Part 5 Chapter 7 Section 1

4 Documentation

Documentation type

Additional description

Z250 – Explosion protected equipment maintenance manual

Info AP

Shows all details including: — inert gas plant including inert gas generator and nitrogen generator Z030 – Arrangement plan

— cooling and cleaning devices

FI

— non-return devices — pressure vacuum devices — inert gas distribution piping. S010 – Piping diagram (PD)

Inerting, purging and gas freeing of cargo tanks and hold spaces.

I200 – Control and monitoring system Inert gas generator. documentation

Inert gas system

Inert gas generator including drying and backflow prevention arrangements.

AP

Z161 – Operational manual

Inert gas generator manual can be part of operation manual required by Sec.18 [1]. See also Sec.9 [2.1].

FI

Nitrogen generator system including drying and backflow prevention arrangements.

AP

Z161 – Operational manual

Nitrogen generator system operational manual can be part of operation manual required by Sec.18 [1]. See also Sec.9 [2.1].

FI

Emergency shut down system G130 – Cause and effect diagram

Cargo tank deck fire extinguishing system

AP

S010 – Piping diagram (PD)

I200 – Control and monitoring system documentation

Fire water system

AP

S010 – Piping diagram (PD)

I200 – Control and monitoring system Nitrogen generator system. documentation

Hydrocarbon gas detection and alarm system, fixed

AP

AP Including all items that gives alarm and automatic shutdown. Can include both cargo handling and fuel.

I200 – Control and monitoring system documentation Z030 – Arrangement plan

AP

AP Detectors, call points and alarm devices.

AP

S010 – Piping diagram (PD)

AP

S030 – Capacity analysis

AP

Z030 – Arrangement plan

AP

G200 – Fixed fire extinguishing system documentation

AP

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 31

Part 5 Chapter 7 Section 1

Object

Documentation type

Additional description

Info

Cargo handling spaces fire extinguishing system

G200 – Fixed fire extinguishing system documentation

AP

External surface protection water-spray system

G200 – Fixed fire extinguishing system documentation

AP

Ventilation systems for cargo handling spaces

Z030 – Arrangement plan

Including gas safe spaces and air locks in cargo area.

AP

Z100 – Specification

Fans.

FI

Cargo handling spaces

C030 – Detailed drawing

Gas tight bulkhead shaft penetrations.

AP

Z254 – Commissioning procedure

Gas trial program for complete cargo system including cargo tank, preferable done at yard.

AP

Z254 – Commissioning procedure

Function tests and capacity tests of the cargo system after delivery, if applicable.

AP

Z161 – Operational manual

Covers items given in Sec.18.

AP

Z100 – Specification

Filling limits of cargo tanks.

FA

S030 – Capacity analysis

Boil of gas handling.

AP

S010 - Piping diagram (PD)

P&ID auxiliary systems like glycol, steam, lube oil, etc.

AP

Z100 – Specification

Product list according to names given in Sec.19.

FI

S010 – Piping diagram (PD)

Cargo and process piping including vapour piping and vent lines of safety relief valves or similar piping, and relief valves discharging liquid cargo from the cargo piping system.

AP

S070 – Pipe stress analysis

When design temperature is below – 110°C.

FI

S090 – Specification of pipes, valve, flanges and fittings

Including non-destructive testing specification. In addition also flame screen, if fitted.

AP

Z030 – Arrangement plan

Protection of hull against cryogenic leakage in way of loading manifolds.

AP

Z100 – Specification

Liquid relief valves.

FI

Z100 – Specification

Insulation including arrangement, if fitted.

FI

Cargo handling arrangement

Cargo piping system

Vapour handling system (boiloff handling)

I200 – Control and monitoring system Vapour handling methods as given documentation in Sec.7 if not included by CMC. Specification should include design Z100 – Specification capacity. S010 - Piping diagram (PD)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

AP FI AP

Page 32

Part 5 Chapter 7 Section 1

Object

Cargo valves control and monitoring system

Documentation type

Additional description

I200 – Control and monitoring system documentation

Info AP

Shows all tank details including: — complete tank with internal structure and bulkheads — secondary barrier, if fitted Z030 – Arrangement plan

— access for inspection — support arrangement with antifloat/roll

FI

— tank insulation — dome arrangement including tank connections — pump tower arrangement. Cargo compartments (general requirements for all tanks)

H131 – Non-destructive testing (NDT) plan

Welds.

AP

M010 – Material specification, metals

Including internal structures and piping.

AP

Z100 – Specification

Insulation manual for all independent tanks with spray on foam.

AP

M060 – Welding procedures (WPS)

AP

P030 - Temperature calculations

Hull steel temperature when cargo temperature is below -10°C.

FI

Z265 – Calculation report

Boil-off calculation.

FI

Z265 – Calculation report

Vibration analysis, if relevant.

FI

H050 – Structural drawing

Support and anti-flotation arrangement.

AP

Including: Cargo independent tank arrangements type A

Cargo independent tank arrangements type B

H080 – Strength analysis

— interaction between hull and tanks — partial filling, if applicable

FI

— cooling-down condition, when cargo temperature is below -55°C. S010 – Piping diagram (PD)

Hold spaces drainage arrangement.

AP

Z161 – Operation manual

Cooling-down procedure for tanks with design temperature below -55°C.

AP

H050 – Structural drawing

Support and anti-flotation arrangement.

AP

Including: H080 – Strength analysis

— interaction between hull and tanks — partial filling, if applicable

FI

— cooling-down condition, when cargo temperature is below -55°C.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 33

Part 5 Chapter 7 Section 1

Object

Documentation type

Additional description

Info

Z161 – Operation manual

Cooling-down procedure.

AP

Z100 – Specification

Small leak protection system, including arrangement.

AP

S010 – Piping diagram (PD)

Nitrogen purging system for insulation spaces.

AP

H050 – Structural drawing

Support and anti-flotation arrangement.

AP

H080 – Strength analysis

Prescriptive stress analysis.

FI

Z252 – Test procedure at manufacture

Stress relieving procedures, thermal or mechanical.

AP

Including: Cargo independent tank arrangements type C H080 – Strength analysis

— finite element analysis of highly stressed tank areas, for e.g. multi-lobe and vacuum insulated tanks

FI

— interaction between hull and tanks — partial filling, if applicable — cooling-down condition, when cargo temperature is below -55°C. Z161 – Operation manual

Cooling-down procedure. Normally not required for small single cylinder tanks.

AP

H050 – Structural drawing

Pump tower and its supports.

AP

Including:

H080 – Strength analysis

— strength and fatigue assessment of pump towers and bottom supports

FI

— partial filling, if applicable — cooling-down condition, when cargo temperature is below -55°C. S010 – Piping diagram (PD)

Nitrogen purging system for insulation spaces.

AP

S010 – Piping diagram (PD)

Water drainage arrangement for secondary insulation space.

AP

Z030 – Arrangement plan

Building principle including location of insulation boxes of different strength rating.

AP

Z100 – Specification

Insulation including load bearing capacities.

AP

Z100 – Specification

Load bearing components.

AP

Z100 – Specification

Materials for membranes and insulation.

AP

Cargo membrane tanks

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 34

Part 5 Chapter 7 Section 1

Object

Cargo compartments over- and under-pressure prevention arrangements

Cargo tanks level monitoring system

Cargo tanks overflow protection system

Cargo temperature monitoring system

Cargo pumps control and monitoring system

Documentation type

Additional description

Z251 – Test procedure

Tightness test of primary and secondary membranes.

AP

Z251 – Test procedure

Strength and tightness test of adjacent ballast tanks.

AP

Z250 – Procedure

Bonding handbook, if secondary barrier is bonded.

AP

Z250 – Procedure

Repair.

AP

Z250 – Procedure

Erection handbook.

FI

Z100 – Specification

Reference list of generic approved documents, if applicable.

FI

Z265 – Calculation report

Vibration analysis.

FI

Z100 – Specification

Relief valves for hold spaces and interbarrier spaces.

FI

Z265 – Calculation report

Required cargo tank relief valve capacity.

AP

Z250 – Procedure

Changing of set pressures of cargo tank safety relief valves, if applicable.

FI

I200 – Control and monitoring system documentation I260 – Plan for periodic test of field instruments

AP Testing procedure including intervals between re-calibration.

I200 – Control and monitoring system documentation I260 – Plan for periodic test of field instruments

Testing procedure including intervals between re-calibration.

I200 – Control and monitoring system documentation I260 – Plan for periodic test of field instruments

Testing procedure including intervals between re-calibration.

Liquefied gas tankers

DNV GL AS

FI AP

I200 – Control and monitoring system documentation

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018

FI AP

I200 - Control and monitoring system documentation

I260 – Plan for periodic test of field instruments

FI AP

I200 – Control and monitoring system documentation For membrane tank systems. Temperature indication system in insulation spaces and Z030 – Arrangement plan cofferdams I260 – Plan for periodic test of field Including intervals between reinstruments calibration.

Cargo pressure alarm system

Info

AP AP FI AP

Including intervals between recalibration.

FI

Page 35

Part 5 Chapter 7 Section 1

Object

Documentation type

Additional description

Info

C020 – Arrangement drawing

FI

I200 – Control and monitoring system documentation Re-liquefaction system

S010 – Piping diagram (PD) Z100 – Specification

If covered by separate CMC delivery, otherwise not applicable. Shall include design capacity and material specifications.

AP AP FI

Z161 – Operation manual

FI

G130 – Cause and effect diagram

AP

AP = for approval; FI = for information ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific

For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

5 Certification requirements 5.1 General 5.1.1 For general certification requirements, see Pt.1 Ch.3 Sec.4 . For a definition of the certification types, see Pt.1 Ch.3 Sec.5 .

5.2 Certification of components Products shall be certified as required in Table 7. Table 7 Certification of components

Object

Additional description Parameter: Size [mm] or PV 1) [-] or other

Rule reference

Society

DN ≥ 100 or working temperature below -55 °C.

Sec.5 [13.1]

PC

manufacturer

DN < 100 or used for isolation of instrumentation lines in piping not greater than 25mm regardless of working temperature.

Sec.5 [13.1]

PC

Society

Certificate type

PC

Issued by

Certification * standard

Valves

Cargo tank pressure relief valves

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Sec.8 [2.2] and Sec.8 [5]

Page 36

Part 5 Chapter 7 Section 1

Object

Issued by

PC

Society

DN ≥ 75

Sec.8 [2.2] and Sec.8 [5]

PC

manufacturer

DN < 75

Sec.8 [2.2] and Sec.8 [5]

Cargo process pressure vessels

PC

Society

Cargo, fuel and Booster pumps

PC

Society

Cargo and fuel compressors

PC

Society

Pt.4 Ch.5

Refrigerant compressors

PC

Society

Pt.4 Ch.7

Pumps for glycol, ethanol, lube oil

PC

manufacturer

Pt.4 Ch.6

Cargo hoses (permanently installed onboard)

PC

Society

Sec.5 [11.6]

Cargo expansion bellows

PC

Society

Sec.5 [11.6]

Ventilation fans and portable ventilators for hazardous spaces

PC

Society

Sec.12

Inert gas generator

PC

Society

Sec.9

Inert gas generator, air blower

PC

manufacturer

Sec.9

Inert gas, scrubber

PC

manufacturer

Sec.9

Inert gas, cooling water pumps for scrubber

PC

manufacturer

Sec.9

PC

Society

PV ≥ 1.5

Sec.9

PC

manufacturer

PV < 1.5

Sec.9

PC

Society

PV ≥ 1.5

Sec.9

PC

manufacturer

PV < 1.5

PC

Society

Nitrogen system, membrane separation vessels

PC

Society

PV ≥ 1.5

Sec.9

PC

manufacturer

PV < 1.5

Sec.9

Nitrogen system, air compressors for nitrogen plant

PC

Society

> 100 kW

Sec.9

PC

manufacturer

≤ 100 kW

Sec.9

PC

Society

Pressure relief valves for cargo system, except for cargo tanks

Inert gas, refrigerant type drier

Inert gas, absorption drier Inert gas, control and monitoring system

Nitrogen system, control and monitoring system

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Sec.5 [13.6] Given in Sec.5 [13.5].

Sec.5 [13.5]

Sec.9

Sec.9

Page 37

Part 5 Chapter 7 Section 1

Rule reference

Certificate type

Object

Certification * standard

Additional description Parameter: Size [mm] or PV 1) [-] or other

Issued by

Associated electrical equipment (motors, frequency converters, switchgear and controlgear) serving an item that is required to be delivered with a Society product certificate

PC

Society

Pt.4 Ch.8 Sec.1 [2.3.2]

Gas combustion unit

PC

manufacturer

Sec.7 [4] and Sec.13 [11]

Re-liquefaction unit (Brayton cycle)

PC

manufacturer

Sec.7 [4] and Sec.13 [11]

Cargo valves control and monitoring system

PC

Society

Sec.13 and Pt.4 Ch.9

Cargo pumps control and monitoring system

PC

Society

Sec.13 and Pt.4 Ch.9

Cargo tanks level monitoring system

PC

Society

Sec.13 and Pt.4 Ch.9

Cargo tanks overflow protection system

PC

Society

Sec.13 and Pt.4 Ch.9

Hydrocarbon gas detection and alarm system, fixed

PC

Society

Sec.13 and Pt.4 Ch.9

Vapour handling control and monitoring system

PC

Society

Emergency shut down system

PC

Society

Applicable for vapour handling methods like gas combustion unit(s) and reliquefaction plant(s) or other methods as given in Sec.7.

Rule reference

Sec.13 and Pt.4 Ch.9

Sec.13, Sec.18 and Pt.4 Ch.9

*Unless otherwise specified the certification standard is the rules. PC = product certificate, MC = material certificate, TR = test report. 1)

PV: pressure × volume as given in Pt.4 Ch.7.

5.3 Material certification of cargo pipe systems and cargo components 5.3.1 The materials used in cargo piping systems shall be supplied with documentation according to Table 8. For definition of material documentation, see Pt.1 Ch.1 Sec.4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 38

Part 5 Chapter 7 Section 1

Certificate type

Object

Certification * standard

Additional description Parameter: Size [mm] or PV 1) [-] or other

Additional description Certificate type

Issued by

MC

Society

pressure

DN > 25

MC

manufacturer

pressure

DN ≤ 25

MC

manufacturer

open ended

MC

manufacturer

pressure

TR

manufacturer

MC

manufacturer

pressure

TR

manufacturer

open ended

MC

Society

pressure

> 100

< -55

MC

manufacturer

pressure

> 100

≥ -55

MC

manufacturer

pressure

≤ 100

TR

manufacturer

open ended

MC

manufacturer

pressure

> 50

TR

manufacturer

pressure

≤ 50

TR

manufacturer

Nuts and bolts

TR

manufacturer

Wooden block

MC

manufacturer

Resin

MC

manufacturer

Object

Pipes

Elbows, t-pieces etc., fabricated by welding

Flanges

Bodies of valves and fittings, pump housings, source materials of steel expansion bellows, other pressure containing components not considered as pressure vessels

Certification * standard

Material

steel

steel

copper alloys

Piping system

Nominal diameter [mm]

Design temperature [°C]

open ended

open ended

*Unless otherwise specified the certification standard is the rules. PC = product certificate, MC = material certificate, TR = test report.

5.4 Documentation requirements for manufacturers Documentation shall be submitted as required by Table 9.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 39

Part 5 Chapter 7 Section 1

Table 8 Certification of material quality and testing

Object

Re-liquefaction system

Documentation type

FI

I200 – Control and monitoring system documentation

AP

S010 – Piping diagram (PD)

Shall include design capacity and material specifications.

G130 – Cause and effect diagram

AP

C020 – Arrangement drawing

FI

I200 – Control and monitoring system documentation

AP

S010 – Piping diagram (PD)

Shall include design capacity and material specifications.

C020 – Arrangement drawing I200 – Control and monitoring system documentation S010 – Piping diagram (PD)

AP FI FI

G130 – Cause and effect diagram

Cargo hoses

FI FI

Z161 – Operation manual

Cargo valves

AP

Z161 – Operation manual

Z100 – Specification

Cargo pumps

Info

C020 – Arrangement drawing

Z100 – Specification

Gas combustion unit

Additional description

FI FI Shall include design capacity and material specifications.

AP

Z100 – Specification

FI

Z161 – Operation manual

FI

C020 – Arrangement drawing

FI

Z100 – Specification

FI

C020 – Arrangement drawing

FI

Z100 – Specification

FI

AP = for approval; FI = for information. ACO = as carried out; L = local handling; R = on request; TA = covered by type approval; VS = vessel specific.

For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

6 Testing 6.1 Testing during newbuilding 6.1.1 Function tests and capacity tests shall be carried out according to a test programme set up by the builder and approved by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 40

Part 5 Chapter 7 Section 1

Table 9 Documentation requirements

6.1.3 All systems covered by this chapter including containment system shall be tested in operation according to approved programme. As far as practicable, these tests shall be performed at the building yard. 6.1.4 Function tests and capacity tests, which cannot be carried out without cargo on board, may be carried at the first cargo loading or transport with a representative cargo. Guidance note 1: For LNG carriers the performance of the cargo system should be verified during first loading and discharging, see IGC code 4.20.3.5 and IACS Unified Interpretation GC 13 (March 2016) Examination before and after the first loaded voyage. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.1.5 Ships equipped with re-liquefaction or refrigeration plant, which: — — — —

is is is is

designed for maintaining the cargo at a pressure below the tank design pressure, or designed for keeping the cargo at a specified condition at port of discharging, or important to safeguard the quality of cargo, or important for the safety,

shall be tested to demonstrate that the capacity of the plant is sufficient at design conditions. Guidance note: This test may be performed by stopping the re-liquefaction plant and record cargo temperature and pressure over given period. Then start up the re-liquefaction plant and run full capacity without the stand-by compressor, and record temperature and pressure decrease of cargo. Together with recording of ambient working conditions, air and seawater temperature, during the test, verification of sufficient capacity can be shown when these parameters are calculated up to design conditions. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.1.6 Heating arrangements, if fitted in accordance with Sec.4 [5.1.1].6, shall be tested to show heating of applicable space as required. 6.1.7 The cargo containment system shall be inspected for cold spots. See Sec.4 [1.1.1] and Sec.4 [5.2.3].7. 6.1.8 Cargo containment system shall be tested. See Sec.4 [5.2.3] and Sec.4 [5.2.4].

7 Signboards 7.1 References 7.1.1 Signboards are required by the rules in: 1) 2) 3) 4) 5)

Sec.3 [2.1.9]: Regarding plates bolted to boundaries facing the cargo area which can be opened for removal of machinery. Sec.6 [9.1.4]: Regarding marking plates for independent tanks, pipes and valves. Sec.12 [3.1.7]: Regarding ventilation system for pump and compressor rooms. Sec.10 [4.1]: Regarding electrical installations. Sec.16 [6.3.10]: Regarding gas operation of propulsion machinery.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 41

Part 5 Chapter 7 Section 1

6.1.2 Testing requirements for class notation Tanker for liquefied gas are given in Sec.4 [5.2.3] and Sec.4 [5.2.4] in general and Sec.20 [1.5], Sec.20 [2.6], Sec.21 [6], Sec.22 [7], Sec.23 [6] and Sec.24 [1.3] for each gas carrier ship type and other relevant parts of the rule set in addition to the ones listed below.

1 General 1.1 Requirements and definitions 1.1.1 Ships shall survive the hydrostatic effects of flooding following assumed hull damage caused by some external force. In addition, to safeguard the ship and the environment, the cargo tanks shall be protected from penetration in the case of minor damage to the ship resulting, for example, from contact with a jetty or tug, and also given a measure of protection from damage in the case of collision or grounding, by locating them at specified minimum distances inboard from the ship's shell plating. Both the damage to be assumed and the proximity of the tanks to the ship's shell shall be dependent upon the degree of hazard presented by the product carried. In addition, the proximity of the cargo tanks to the ship's shell shall be dependent upon the volume of the cargo tank. 1.1.2 Ships subject to this chapter shall be designed to one of the following standards:

.1

A type 1G ship is a gas carrier intended to transport the products indicated in Sec.19 that require maximum preventive measures to preclude their escape.

.2

A type 2G ship is a gas carrier intended to transport the products indicated in Sec.19 that require significant preventive measures to preclude their escape.

.3

A type 2PG ship is a gas carrier of 150 m in length or less intended to transport the products indicated in Sec.19 that require significant preventive measures to preclude their escape, and where the products are carried in type C independent tanks designed (see Sec.4 and Sec.22) for a MARVS of at least 0.7 MPa gauge and a cargo containment system design temperature of -55°C or above. A ship of this description that is over 150 m in length shall be considered a type 2G ship.

.4

A type 3G ship is a gas carrier intended to carry the products indicated in Sec.19 that require moderate preventive measures to preclude their escape.

Therefore, a type 1G ship is a gas carrier intended for the transportation of products considered to present the greatest overall hazard and types 2G/2PG and type 3G for products of progressively lesser hazards. Accordingly, a type 1G ship shall survive the most severe standard of damage and its cargo tanks shall be located at the maximum prescribed distance inboard from the shell plating. 1.1.3 The ship type required for individual products is indicated in column c in Sec.19 Table 2. 1.1.4 If a ship is intended to carry more than one of the products listed in Sec.19, the standard of damage shall correspond to the product having the most stringent ship type requirements. The requirements for the location of individual cargo tanks, however, are those for ship types related to the respective products intended to be carried. 1.1.5 The position of the moulded line for different containment systems is shown in [4.1].

2 Freeboard and stability 2.1 General requirements 2.1.1 Ships may be assigned the minimum freeboard permitted by the international convention on load lines in force. However, the draught associated with the assignment shall not be greater than the maximum draught otherwise permitted by the rules.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 42

Part 5 Chapter 7 Section 2

SECTION 2 SHIP SURVIVAL CAPABILITY AND LOCATION OF CARGO TANKS

2.1.3 When calculating the effect of free surfaces of consumable liquids for loading conditions, it shall be assumed that, for each type of liquid, at least one transverse pair or a single centre tank has a free surface. The tank or combination of tanks to be taken into account shall be those where the effect of free surfaces is the greatest. The free surface effect in undamaged compartments shall be calculated by a method according to the international code on intact stability. 2.1.4 Solid ballast shall not normally be used in double bottom spaces in the cargo area. Where, however, because of stability considerations, the fitting of solid ballast in such spaces becomes unavoidable, its disposition shall be governed by the need to enable access for inspection and to ensure that the impact loads resulting from bottom damage are not directly transmitted to the cargo tank structure. 2.1.5 The master of the ship shall be supplied with a loading and stability information booklet. This booklet shall contain details of typical service conditions, loading, unloading and ballasting operations, provisions for evaluating other conditions of loading and a summary of the ship's survival capabilities. The booklet shall also contain sufficient information to enable the master to load and operate the ship in a safe and seaworthy manner. 2.1.6 All ships, subject to this chapter shall be fitted with a stability instrument, capable of verifying compliance with intact and damage stability requirements, approved by the Society (see guidance note).

.1

ships constructed before 1 July 2016 shall comply with this paragraph at the first scheduled renewal survey of the ship after (date of entry into force) but not later than (five years after date of entry into force)

.2

notwithstanding the requirements of paragraph .1 a stability instrument installed on a ship constructed before 1 July 2016 need not be replaced provided it is capable of verifying compliance with intact and damage stability, to the satisfaction of the Society, and

.3

for the purposes of control under SOLAS regulation XI-1/4, the Society shall issue a document of approval for the stability instrument. Guidance note: Refer to part B, chapter 4, of the international code on intact stability, 2008 (2008 IS code), as amended; the guidelines for the approval of stability instruments (MSC.1/Circ.1229), annex, section 4, as amended; and the technical standards defined in part 1 of the guidelines for verification of damage stability requirements for tankers (MSC.1/Circ.1461). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.7 The Society may give special dispensation to the following ships from the requirements of [2.1.6], provided that the procedures employed for intact and damage stability verification, maintain the same degree of safety as being loaded in accordance with the approved conditions (see below guidance note). Any such dispensation shall be duly noted on the international certificate of fitness.

.1

ships which are on a dedicated service, with a limited number of permutations of loading such that all anticipated conditions have been approved in the stability information provided to the master in accordance with the requirements of paragraph [2.1.5]

.2 .3 .4

ships where stability verification is made remotely by a means approved by the Society ships which are loaded within an approved range of loading conditions, or ships constructed before 1 July 2016 provided with approved limiting KG/GM curves covering all applicable intact and damage stability requirements.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 43

Part 5 Chapter 7 Section 2

2.1.2 The stability of the ship, in all seagoing conditions and during loading and unloading cargo, shall comply with the requirements of the international code on intact stability. This includes partial filling and loading and unloading at sea, when applicable. Stability during ballast water operations shall fulfil stability criteria.

Refer to operational guidance provided in part 2 of the Guidelines for verification of damage stability requirements for tankers (MSC.1/Circ.1461). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.8 Conditions of loading Damage survival capability shall be investigated on the basis of loading information for all anticipated conditions of loading and variations in draught and trim. This shall include ballast and, where applicable, cargo heel.

3 Damage assumptions 3.1 Maximum extent of damage 3.1.1 The assumed maximum extent of damage shall be as given in Table 1: Table 1 Assumed maximum extent of damage 1

Side damage

1.1

longitudinal extent

1/3 LLL

1.2

transverse extent measured inboard from the moulded line of the outer shell at right angles

B/5 or 11.5 m, whichever is less

2/3

or 14.5 m, whichever is less

to the centreline at the level of the summer waterline 1.3

vertical extent from the moulded line of the outer shell at right angles to the centreline

upwards, without limit

2

bottom damage

for 0.3 LLL from the forward perpendicular of the ship

2.1

longitudinal extent

1/3 LLL or 14.5 m, whichever is less

1/3 LLL or 14.5 m, whichever is less

2.2

transverse extent

B/6 or 10 m, whichever is less

B/6 or 5 m, whichever is less

vertical extent

B/15 or 2 m, whichever is less, measured from the moulded line of the bottom shell plating at centreline, see [4.1.3]

B/15 or 2 m, whichever is less measured from the moulded line of the bottom shell plating at centreline, see [4.1.3]

2/3

2.3

any other part of the ship 2/3

3.1.2 Other damage If any damage of a lesser extent than the maximum damage specified in [3.1.1] would result in a more 1. severe condition, such damage shall be assumed.

2.

Local damage anywhere in the cargo area extending inboard distance d as defined in [4.1.1], measured normal to the moulded line of the outer shell shall be considered. Bulkheads shall be

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 44

Part 5 Chapter 7 Section 2

Guidance note:

4 Location of cargo tanks 4.1 General requirements 4.1.1 Cargo tanks shall be located at the following distances inboard:

.1

Type 1G ships: from the moulded line of the outer shell, not less than the transverse extent of damage specified in [3.1.1].1.2 and, from the moulded line of the bottom shell at centerline, not less than the vertical extent of damage specified in [3.1.1].2.3, and nowhere less than d where d is as follows:

.1 .2 .3 .4

3

for Vc below or equal 1000 m , d = 0.8 m 3

3

for 1000 m < Vc < 5000 m , d = 0.75+ Vc× 0.2/4000 m 3

3

for 5000 m ≤ Vc < 30 000 m , d = 0.8 + Vc/25 000 m, and 3

for Vc ≥ 30 000 m , d = 2 m.

where: Vc corresponds to 100% of the gross design volume of the individual cargo tank at 20°C, including domes and appendages (see Figure 1 and Figure 2. For the purpose of cargo tank protective distances, the cargo tank volume is the aggregate volume of all the parts of tank that have a common bulkhead(s), and d is measured at any cross section at a right angle from the moulded line of outer shell. Tank size limitations may apply to type 1G ship cargoes in accordance with Sec.17.

.2

Types 2G/2PG: from the moulded line of the bottom shell at centerline not less than the vertical extent of damage specified in [3.1.1].2.3 and nowhere less than d as indicated in [4.1.1].1 (see Figure 1 and Figure 3).

.3

Type 3G ships: from the moulded line of the bottom shell at centerline not less than the vertical extent of damage specified in [3.1.1].2.3 and nowhere less than d, where d = 0.8 m from the moulded line of outer shell (see Figure 1 and Figure 4).

4.1.2 For the purpose of tank location, the vertical extent of bottom damage shall be measured to the inner bottom when membrane or semi-membrane tanks are used, otherwise to the bottom of the cargo tanks. The transverse extent of side damage shall be measured to the longitudinal bulkhead when membrane or semimembrane tanks are used, otherwise to the side of the cargo tanks. The distances indicated in [3.1] and [4.1] shall be applied as in Figure 5 to Figure 9. These distances shall be measured plate to plate, from the moulded line to the moulded line, excluding insulation.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 45

Part 5 Chapter 7 Section 2

assumed damaged when the relevant sub-paragraphs of [6.1.1] apply. If a damage of a lesser extent than d would result in a more severe condition, such damage shall be assumed.

Part 5 Chapter 7 Section 2 Figure 1 Cargo tank locations centreline profile – type 1G, 2G, 2PG and 3G ships

Figure 2 Transverse sections- type 1G ship

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 46

Part 5 Chapter 7 Section 2 Figure 3 Transverse sections- type 2G and 2PG ship

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 47

Part 5 Chapter 7 Section 2 Figure 4 Transverse sections – type 3G ship

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 48

Part 5 Chapter 7 Section 2 Figure 5 Protective distance independent prismatic tank

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 49

Part 5 Chapter 7 Section 2 Figure 6 Protective distance semi-membrane tank

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 50

Part 5 Chapter 7 Section 2 Figure 7 Protective distance membrane tank

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 51

Part 5 Chapter 7 Section 2 Figure 8 Protective distance spherical tank

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 52

Part 5 Chapter 7 Section 2 Figure 9 Protective distance pressure type tank 4.1.3 Except for type 1G ships, suction wells installed in cargo tanks may protrude into the vertical extent of bottom damage specified in [3.1.1] 2.3 provided that such wells are as small as practicable and the protrusion below the inner bottom plating does not exceed 25% of the depth of the double bottom or 350 mm, whichever is less. Where there is no double bottom, the protrusion below the upper limit of bottom damage shall not exceed 350 mm. Suction wells installed in accordance with this paragraph may be ignored when determining the compartments affected by damage. 4.1.4 Cargo tanks shall not be located forward of the collision bulkhead.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 53

5.1 General requirements 5.1.1 The requirements of [7.1] shall be confirmed by calculations that take into consideration the design characteristics of the ship, the arrangements, configuration and contents of the damaged compartments, the distribution, relative densities and the free surface effects of liquids and the draught and trim for all conditions of loading. 5.1.2 The permeabilities of spaces assumed to be damaged shall be as given in Table 2: Table 2 Permeability of damaged spaces Spaces

Permeabilities

stores

0.6

accommodation

0.95

machinery

0.85

voids

0.95

hold spaces

0.95

(1)

consumable liquids

0 to 0.95

(2)

other liquids

0 to 0.95

(2)

notes 1)

Other values of permeability can be considered based on detailed calculations. Interpretations of regulation of part B-1 of SOLAS chapter II-1 (MSC/Circ.651) are referred.

2)

The permeability of partially filled compartments shall be consistent with the amount of liquid carried in the compartment.

5.1.3 Wherever damage penetrates a tank containing liquids, it shall be assumed that the contents are completely lost from that compartment and replaced by salt water up to the level of the final plane of equilibrium. 5.1.4 Where damage between transverse watertight bulkheads is envisaged, as specified in [6.1.1] 4), [6.1.1] 5), and [6.1.1] 6), transverse bulkheads shall be spaced at least at a distance equal to the longitudinal extent of damage specified in [3.1.1] 1.1 in order to be considered effective. Where transverse bulkheads are spaced at a lesser distance, one or more of these bulkheads within such extent of damage shall be assumed as non-existent for the purpose of determining flooded compartments. Further, any portion of a transverse bulkhead bounding side compartments or double bottom compartments, shall be assumed damaged if the watertight bulkhead boundaries are within the extent of vertical or horizontal penetration required by [3.1]. Also, any transverse bulkhead shall be assumed damaged if it contains a step or recess of more than 3 m in length located within the extent of penetration of assumed damage. The step formed by the after peak bulkhead and the after peak tank top shall not be regarded as a step for the purpose of this paragraph. 5.1.5 The ship shall be designed to keep unsymmetrical flooding to the minimum consistent with efficient arrangements.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 54

Part 5 Chapter 7 Section 2

5 Flood assumptions

5.1.7 If pipes, ducts, trunks or tunnels are situated within the assumed extent of damage penetration, as defined in [3.1], arrangements shall be such that progressive flooding cannot thereby extend to compartments other than those assumed to be flooded for each case of damage. 5.1.8 The buoyancy of any superstructure directly above the side damage shall be disregarded. However, the unflooded parts of superstructures beyond the extent of damage may be taken into consideration, provided that the following conditions are complied with.

.1

they are separated from the damaged space by watertight divisions and the requirements of [7.1.1].1 in respect of these intact spaces are complied with, and

.2

openings in such divisions are capable of being closed by remotely operated sliding watertight doors and unprotected openings are not immersed within the minimum range of residual stability required in [7.1.2].1. However, the immersion of any other openings capable of being closed weather tight may be permitted.

6 Standard of damage 6.1 Damage related to ship types 6.1.1 Ships shall be capable of surviving the damage indicated in [3.1] with the flood assumptions in [5.1], to the extent determined by the ship's type, according to the following standards.

.1 .2

a type 1G ship shall be assumed to sustain damage anywhere in its length, LLL

.3

a type 2G ship of 150 m in length or less shall be assumed to sustain damage anywhere in its length, except involving either of the bulkheads bounding a machinery space located aft

.4

a type 2PG ship shall be assumed to sustain damage anywhere in its length except involving transverse bulkheads spaced further apart than the longitudinal extent of damage as specified in [3.1.1].1.1

.5

a type 3G ship of 80 m in length or more shall be assumed to sustain damage anywhere in its length, except involving transverse bulkheads spaced further apart than the longitudinal extent of damage specified [3.1.1].1.1, and

.6

a type 3G ship less than 80 m in length shall be assumed to sustain damage anywhere in its length, except involving transverse bulkheads spaced further apart than the longitudinal extent of damage specified in [3.1.1].1.1 and except damage involving the machinery space when located after.

a type 2G ship of more than 150 m in length shall be assumed to sustain damage anywhere in its length

6.1.2 In the case of small type 2G/2PG and 3G ships that do not comply in all respects with the appropriate requirements of [6.1.1] 3), [6.1.1] 4) and [6.1.1] 6), special dispensations may only be considered if alternative measures can be taken which maintain the same degree of safety. The nature of the alternative measures shall be approved and clearly stated and be available to the port administration. Any such dispensation shall be duly noted on the international certificate of fitness for the carriage of liquefied gases in bulk.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 55

Part 5 Chapter 7 Section 2

5.1.6 Equalization arrangements requiring mechanical aids such as valves or cross-levelling pipes, if fitted, shall not be considered for the purpose of reducing an angle of heel or attaining the minimum range of residual stability to meet the requirements of [7.1.1], and sufficient residual stability shall be maintained during all stages where equalization is used. Spaces linked by ducts of large cross-sectional area may be considered to be common.

7.1 General requirements Ships subject to the rules shall be capable of surviving the assumed damage specified in [3.1], to the standard provided in [6.1], in a condition of stable equilibrium and shall fulfil following criteria. 7.1.1 In any stage of flooding, following criteria shall be fulfilled:

.1

The waterline, taking into account sinkage, heel and trim, shall be below the lower edge of any opening through which progressive flooding or downflooding may take place. Such openings shall include air pipes and openings that are closed by means of weather tight doors or hatch covers and may exclude those openings closed by means of watertight manhole covers and watertight flush scuttles, small watertight cargo tank hatch covers that maintain the high integrity of the deck, remotely operated watertight sliding doors and side scuttles of the non-opening type.

.2 .3

The maximum angle of heel due to unsymmetrical flooding shall not exceed 30°, and: The residual stability during intermediate stages of flooding shall not be less than that required by [7.1.2].1.

7.1.2 At final equilibrium after flooding, following criteria shall be fulfilled.

.1

the righting lever curve shall have a minimum range of 20° beyond the position of equilibrium in association with a maximum residual righting lever of at least 0.1 m within the 20° range; the area under the curve within this range shall not be less than 0.0175 m-radians. The 20° range may be measured from any angle commencing between the position of equilibrium and the angle of 25° (or 30° if no deck immersion occurs). Unprotected openings shall not be immersed within this range unless the space concerned is assumed to be flooded. Within this range, the immersion of any of the openings listed in [7.1.1].1 and other openings capable of being closed weather tight may be permitted, and

.2

the emergency source of power shall be capable of operating.

Note that other openings capable of being closed weathertight do not include ventilators (complying with ILLC 19(4)) that for operational reasons have to remain open to supply air to the engine room or emergency generator room (if the same is considered buoyant in the stability calculation or protecting openings leading below) for the effective operation of the ship. Reference is made to IACS GC17.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 56

Part 5 Chapter 7 Section 2

7 Survival of ship

1 Segregation of the cargo area 1.1 General requirements 1.1.1 Hold spaces shall be segregated from machinery and boiler spaces, accommodation spaces, service spaces, control stations, chain lockers, domestic water tanks and from stores. Hold spaces shall be located forward of machinery spaces of category A. Alternative arrangements, including locating machinery spaces of category A forward, may be accepted, based on SOLAS regulation II-2/17, after further consideration of involved risks, including that of cargo release and the means of mitigation. 1.1.2 Where cargo is carried in a cargo containment system not requiring a complete or partial secondary barrier, segregation of hold spaces from spaces referred to in [1.1.1] or spaces either below or outboard of the hold spaces, may be effected by cofferdams, oil fuel tanks or a single gastight bulkhead of all-welded construction forming an A-60 class division. A gastight A-0 class division is acceptable if there is no source of ignition or fire hazard in the adjoining spaces. 1.1.3 Where cargo is carried in a cargo containment system requiring a complete or partial secondary barrier, segregation of hold spaces from spaces referred to in [1.1.1], or spaces either below or outboard of the hold spaces that contain a source of ignition or fire hazard, shall be effected by cofferdams or oil fuel tanks. A gastight A-0 class division is acceptable if there is no source of ignition or fire hazard in the adjoining spaces. 1.1.4 Turret compartments segregation from spaces referred to in [1.1.1], or spaces either below or outboard of the turret compartment that contain a source of ignition or fire hazard, shall be effected by cofferdams or an A-60 class division. A gastight A-0 class division is acceptable if there is no source of ignition or fire hazard in the adjoining spaces. 1.1.5 In addition, the risk of fire propagation from turret compartments to adjacent spaces, shall be evaluated by a risk analysis, see Sec.1 [2.1.5] and further preventive measures, such as the arrangement of a cofferdam around the turret compartment, shall be provided if needed. 1.1.6 When cargo is carried in a cargo containment system requiring a complete or partial secondary barrier, following requirements apply.

.1 .2

at temperatures below -10°C, hold spaces shall be segregated from the sea by a double bottom, and at temperatures below -55°C, the ship shall also have a longitudinal bulkhead forming side tanks.

1.1.7 Arrangements shall be made for sealing the weather decks in way of openings for cargo containment systems. The sealing material shall be such that it will not deteriorate, even at considerable movements between the tanks and the deck. The sealing shall be able to withstand all temperatures and environmental hazards which may be expected.

2 Accommodation, service and machinery spaces and control station 2.1 General requirements 2.1.1 No accommodation space, service space or control station shall be located within the cargo area. The bulkhead of accommodation spaces, service spaces or control stations that face the cargo area, shall be so

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 57

Part 5 Chapter 7 Section 3

SECTION 3 SHIP ARRANGEMENTS

2.1.2 To guard against the danger of hazardous vapours, due consideration shall be given to the location of air intakes/outlets and openings into accommodation, service and machinery spaces and control stations in relation to cargo piping, cargo vent systems and machinery space exhausts from gas burning arrangements. 2.1.3 Access through doors, gastight or otherwise, shall not be permitted from a non-hazardous area to a hazardous area except for access to service spaces forward of the cargo area through airlocks, as permitted by [6.1.1], when accommodation spaces are aft. 2.1.4 Arrangements facing cargo area Entrances, air inlets and openings to accommodation spaces, service spaces, machinery spaces and .1 control stations shall not face the cargo area. They shall be located on the end bulkhead not facing the cargo area or on the outboard side of the superstructure or deckhouse or on both at a distance of at least 4 % of the length (LLL) of the ship but not less than 3 m from the end of the superstructure or deckhouse facing the cargo area. This distance, however, need not exceed 5 m. Air outlets are subject to the same requirements as air inlets/intakes.

.2

Windows and sidescuttles facing the cargo area and on the sides of the superstructures or deckhouses within the distance mentioned above shall be of the fixed (non-opening) type. Wheelhouse windows may be non-fixed and wheelhouse doors may be located within the above limits so long as they are designed in a manner that a rapid and efficient gas and vapour tightening of the wheelhouse can be ensured.

.3

For ships dedicated to the carriage of cargoes that have neither flammable nor toxic hazards, the Society may approve relaxations from the above requirements.

.4

Accesses to forecastle spaces containing sources of ignition may be permitted through a single door facing the cargo area, provided the doors are located outside hazardous areas as defined in Sec.10.

2.1.5 Windows and sidescuttles facing the cargo area and on the sides of the superstructures and deckhouses within the limits specified in [2.1.4], except wheelhouse windows, shall be constructed to A-60 class. Wheelhouse windows shall be constructed to not less than A-0 class (for external fire load). Sidescuttles in the shell below the uppermost continuous deck and in the first tier of the superstructure or deckhouse shall be of fixed (non-opening) type. Guidance note: The sentence "Wheelhouse windows shall be constructed to not less than A-0 class (for external fire load)" has been deleted by IMO Resolution MSC.411(97). This resolution will normally enter into force 1 January 2020. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.6 All air intakes, outlets and other openings into the accommodation spaces, service spaces and control stations shall be fitted with closing devices. When carrying toxic products, they shall be capable of being operated from inside the space. The requirement for fitting air intakes and openings with closing devices operated from inside the space for toxic products need not apply to spaces not normally manned, such as deck stores, forecastle stores, workshops. In addition, the requirement does not apply to cargo control rooms located within the cargo area.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 58

Part 5 Chapter 7 Section 3

located as to avoid the entry of gas from the hold space to such spaces through a single failure of a deck or bulkhead on a ship having a containment system requiring a secondary barrier.

The closing devices need not be operable from within the single spaces and may be located in centralized positions. Engine room casings, cargo machinery spaces, electric motor rooms and steering gear compartments are generally considered as spaces not covered by [2.1.6] and therefore the requirement for closing devices may be disregarded for these spaces. The closing devices are to give a reasonable degree of gas tightness. Ordinary steel fire-flaps without gaskets/seals are not to be considered satisfactory. Regardless of this interpretation, the closing devices shall be operable from outside of the protected space (SOLAS regulation II-2/5.2.1.1). See IACS UI GC 15 and MSC.1/Circ.1559. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.7 Control rooms and machinery spaces of turret systems may be located in the cargo area forward or aft of cargo tanks in ships with such installations. Access to such spaces containing sources of ignition may be permitted through doors facing the cargo area, provided the doors are located outside hazardous areas or access is through airlocks. 2.1.8 Where a corner-to-corner situation occurs between a non-hazardous space and a cargo tank, a cofferdam created by a diagonal plate across the corner on the non-hazardous side, may be accepted as separation. 2.1.9 Bolted plates for removal of machinery may be fitted in boundaries facing the cargo area. Such plates shall be insulated to A-60 class, see Sec.11. Signboards giving instruction that the plates shall be kept closed unless the ship is gas-free, shall be posted near the plates.

3 Cargo machinery spaces and turret compartments 3.1 General requirements 3.1.1 Cargo machinery spaces shall be situated above the weather deck and located within the cargo area. Cargo machinery spaces and turret compartments shall be treated as cargo pump-rooms for the purpose of fire protection according to SOLAS regulation II-2/9.2.4, and for the purpose of prevention of potential explosion according to SOLAS regulation ll-2/4.5.10. Guidance note: Measures for preventing explosion required by SOLAS are gas detection and temperature monitoring of shaft glands and pump/ compressor bearings. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: The sentence "for the purpose of prevention of potential explosion according to SOLAS regulation ll-2/4.5.10" does not require application of the aforementioned SOLAS regulation. SOLAS regulation II-2/4.5.10 does not apply in accordance with Sec.10. See MSC.1/Circ.1559 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.2 When cargo machinery spaces are located at the after end of the aftermost hold space or at the forward end of the foremost hold space, the limits of the cargo area, as defined in Sec.1 [3.1], shall be extended to include the cargo machinery spaces for the full breadth and depth of the ship and the deck areas above those spaces. 3.1.3 Where the limits of the cargo area are extended by [3.1.2], the bulkhead that separates the cargo machinery spaces from accommodation and service spaces, control stations and machinery spaces of category A shall be located so as to avoid the entry of gas to these spaces through a single failure of a deck or bulkhead.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 59

Part 5 Chapter 7 Section 3

Guidance note:

3.1.5 Arrangements of cargo machinery spaces and turret compartments shall ensure safe unrestricted access for personnel wearing protective clothing and breathing apparatus, and in the event of injury to allow unconscious personnel to be removed. At least two widely separated escape routes and doors shall be provided in cargo machinery spaces, except that a single escape route may be accepted where the maximum travel distance to the door is 5 m or less. 3.1.6 All valves necessary for cargo handling shall be readily accessible to personnel wearing protective clothing. Suitable arrangements shall be made to deal with drainage of pump and compressor rooms. 3.1.7 Turret compartments shall be designed to retain their structural integrity in case of explosion or uncontrolled high-pressure gas release (overpressure and/or brittle fracture), the characteristics of which shall be substantiated on the basis of a risk analysis with due consideration of the capabilities of the pressure relieving devices. Turret compartment should be provided with explosion pressure relief arrangements unless structure analysis show that the turret compartment can contain the explosion pressure.

4 Cargo control rooms 4.1 General requirements 4.1.1 Any cargo control room shall be above the weather deck and may be located in the cargo area. The cargo control room may be located within the accommodation spaces, service spaces or control stations, provided the following conditions are complied with:

.1 .2

the cargo control room is a non-hazardous area

.3

if the entrance does not comply with [2.1.4] .1, the cargo control room shall have no access to the spaces described above and the boundaries for such spaces shall be insulated to A-60 class.

if the entrance complies with [2.1.4] .1, the control room may have access to the spaces described above, and

4.1.2 If the cargo control room is designed to be a non-hazardous area, instrumentation shall, as far as possible, be by indirect reading systems and shall, in any case, be designed to prevent any escape of gas into the atmosphere of that space. Location of the gas detection system within the cargo control room will not cause the room to be classified as a hazardous area, if installed in accordance with Sec.13 [6.1.11]. 4.1.3 If the cargo control room for ships carrying flammable cargoes is classified as a hazardous area, sources of ignition shall be excluded and any electrical equipment shall be installed in accordance with Sec.10.

5 Access to spaces in the cargo area 5.1 General requirements 5.1.1 Visual inspection of at least one side of the inner hull structure shall be possible without the removal of any fixed structure or fitting. If such a visual inspection, whether combined with those inspections required in [5.1.2], Sec.4 [2.4.2] 4) or Sec.4 [5.2.3] 7) or not, is only possible at the outer face of the inner hull, the inner hull shall not be a fuel-oil tank boundary wall.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 60

Part 5 Chapter 7 Section 3

3.1.4 Cargo compressors and cargo pumps may be driven by electric motors in an adjacent non-hazardous space separated by a bulkhead or deck, if the seal around the bulkhead penetration ensures effective gastight segregation of the two spaces. Alternatively, such equipment may be driven by certified safe electric motors adjacent to them if the electrical installation complies with the requirements of Sec.10.

5.1.3 Arrangements for hold spaces, void spaces, cargo tanks and other spaces classified as hazardous areas, shall be such as to allow entry and inspection of any such space by personnel wearing protective clothing and breathing apparatus and shall also allow for the evacuation of injured and/or unconscious personnel. Such arrangements shall comply with the following:

.1

Access shall be provided as follows:

.1 .2

access to all cargo tanks. Access shall be direct from the weather deck access through horizontal openings, hatches or manholes. The dimensions shall be sufficient to allow a person wearing a breathing apparatus to ascend or descend any ladder without obstruction, and also to provide a clear opening to facilitate the hoisting of an injured person from the bottom of the space. The minimum clear opening shall be not less than 600 mm × 600 mm Guidance note: The minimum clear opening of 600 mm × 600 mm may have corner radii up to 100 mm maximum. In such a case where as a consequence of structural analysis of a given design the stress is to be reduced around the opening, it is considered appropriate to take measures to reduce the stress such as making the opening larger with increased radii, e.g. 600 × 800 with 300 mm radii, in which a clear opening of 600 mm × 600 mm with corner radii up to 100 mm maximum fits. Reference is made IACS GC 16 March 2016 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

.3

access through vertical openings or manholes providing passage through the length and breadth of the space. The minimum clear opening shall be not less than 600 mm × 800 mm at a height of not more than 600 mm from the bottom plating unless gratings or other footholds are provided, and

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 61

Part 5 Chapter 7 Section 3

5.1.2 Inspection of one side of any insulation in hold spaces shall be possible. If the integrity of the insulation system can be verified by inspection of the outside of the hold space boundary when tanks are at service temperature, inspection of one side of the insulation in the hold space need not be required.

The minimum clear opening of not less than 600 mm × 800 mm may also include an opening with corner radii of 300 mm. An opening of 600 mm in height × 800 mm in width may be accepted as access openings in vertical structures where it is not desirable to make large opening in the structural strength aspects, i.e. girders and floors in double bottom tanks. Reference is made IACS GC 16 March 2016

800

30

0

See figure Figure 1.

30 0

600

Figure 1 Minimum clear opening of not less than 600 × 800 mm ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 62

Part 5 Chapter 7 Section 3

Guidance note:

Subject to verification of easy evacuation of injured person on a stretcher the vertical opening 850 mm × 620 mm with wider upper half than 600 mm, while the lower half may be less than 600 mm with the overall height not less than 850 mm is considered an acceptable alternative to the traditional opening of 600 mm × 800 mm with corner radii of 300 mm. Reference is made IACS GC 16 March 2016 See figure Figure 2.

Figure 2 Minimum clear opening of less than 600 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: If a vertical opening is at a height of more than 600 mm steps and handgrips are to be provided. In such arrangements it is to be demonstrated that an injured person can be easily evacuated. Reference is made IACS GC 16 March 2016 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

.4

circular access openings to type C tanks shall have a diameter of not less than 600 mm.

.2

The dimensions referred to in .1.2 and .1.3 may be decreased, if the requirements of [5.1.3] can be met.

.3

Where cargo is carried in a containment system requiring a secondary barrier, the requirements of .1.2 and .1.3 do not apply to spaces separated from a hold space by a single gastight steel boundary. Such spaces shall be provided only with direct or indirect access from the weather deck, not including any enclosed non-hazardous area.

.4

Access required for inspection shall be a designated access through structures below and above cargo tanks, which shall have at least the cross-sections as required by .1.3.

.5

For the purpose of [5.1.1] or [5.1.2], the following shall apply:

.1

Where it is required to pass between the surface to be inspected, flat or curved, and structures such as deck beams, stiffeners, frames, girders, etc., the distance between that surface and the free edge of the structural elements shall be at least 380 mm. The distance between the surface to be inspected and the surface to which the above structural elements are fitted, e.g. deck, bulkhead or shell, shall be at least 450 mm for a curved tank surface, e.g. for a type C tank, or 600 mm for a flat tank surface, e.g. for a type A tank, see Figure 3.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 63

Part 5 Chapter 7 Section 3

Guidance note:

passage

cargo tank

Figure 3 Minimum passage requirements involving structural elements

600/450

Where it is not required to pass between the surface to be inspected and any part of the structure, for visibility reasons the distance between the free edge of that structural element and the surface to be inspected shall be at least 50 mm or half the breadth of the structure's face plate, whichever is the larger, see Figure 4.

380

.2

passage

cargo tank

Figure 4 Minimum visibility requirements

.3

If for inspection of a curved surface where it is required to pass between that surface and another surface, flat or curved, to which no structural elements are fitted, the distance between both surfaces shall be at least 380 mm, see Figure 5. Where it is not required to pass between that curved surface and another surface, a smaller distance than 380 mm may be accepted taking into account the shape of the curved surface.

flat surface of ship structure 380

cargo tank

380

Figure 5 Minimum passage requirements between two curved surfaces

.4

If for inspection of an approximately flat surface where it is required to pass between two approximately flat and approximately parallel surfaces, to which no structural elements are fitted, the distance between those surfaces shall be at least 600 mm. Where fixed access ladders are fitted, a clearance of at least 450 mm shall be provided for access, see Figure 6.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 64

Part 5 Chapter 7 Section 3

380

600/450

ship structure

flat surface of tank

600

flat surface of ship structure

450

step of access ladder

Figure 6 Minimum passage requirements between flat surfaces The minimum distances between a cargo tank sump and adjacent double bottom structure in way of a suction well shall not be less than those shown in Figure 7 This figure shows that the distance between the plane surfaces of the sump and the well is a minimum of 150 mm and that the clearance between the well and the knuckle point between the spherical or circular surface and sump of the tank is at least 380 mm. If there is no suction well, the distance between the cargo tank sump and the inner bottom shall not be less than 50 mm.

0

.5

150

38

inner bottom

150

Figure 7 Minimum distance requirements involving a cargo sump

.6

The distance between a cargo tank dome and deck structures shall not be less than 150 mm, see Figure 8.

150 deck structure

Figure 8 Minimum distance requirement between cargo tank dome and deck structures

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 65

Part 5 Chapter 7 Section 3

600

Fixed or portable staging shall be installed as necessary for inspection of cargo tanks, cargo tank supports and restraints, e.g. anti-pitching, anti-rolling and anti-flotation chocks, cargo tank insulation etc. This staging shall not impair the clearances specified in .5.1 to .5.4, and:

.8

If fixed or portable ventilation ducting shall be fitted in compliance with Sec.12 [1.1.2], such ducting shall not impair the distances required under .5.1 to .5.4.

5.1.4 Access from the open weather deck to non-hazardous areas shall be located outside the hazardous areas as defined in [6], unless the access is by means of an airlock in accordance with Sec.12. 5.1.5 Turret compartments shall be arranged with two independent means of access/egress. 5.1.6 Access from a hazardous area below the weather deck to a non-hazardous area is not permitted.

6 Airlocks 6.1 General requirements 6.1.1 Access between hazardous area on the open weather deck and non-hazardous spaces shall be by means of an airlock. This shall consist of two self-closing, substantially gastight, steel doors without any holding back arrangements, capable of maintaining the overpressure, at least 1.5 m but no more than 2.5 m apart. The airlock space shall be artificially ventilated from a non-hazardous area and maintained at an overpressure to the hazardous area on the weather deck. 6.1.2 Where spaces are protected by pressurization, the ventilation shall be designed and installed in accordance with Sec.12. 6.1.3 An audible and visible alarm system to give a warning on both sides of the airlock shall be provided. The visible alarm shall indicate if one door is open. The audible alarm shall sound if doors on both sides of the air lock are moved from the closed positions. 6.1.4 In ships carrying flammable products, electrical equipment that is located in spaces protected by airlocks and not of the certified safe type, shall be de-energized in case of loss of overpressure in the space. 6.1.5 Electrical equipment for manoeuvring, anchoring and mooring, as well as emergency fire pumps that are located in spaces protected by airlocks, shall be of a certified safe type. 6.1.6 The airlock space shall be monitored for cargo vapours, see Sec.13 [6]. 6.1.7 Subject to the requirements of the international convention on load lines in force, the door sill shall not be less than 300 mm in height. 6.1.8 Air locks shall have a simple geometrical form. Air locks shall not be used for other purposes, for instance as store rooms.

7 Bilge, ballast and oil fuel arrangements 7.1 General requirements 7.1.1 Where cargo is carried in a cargo containment system not requiring a secondary barrier, suitable drainage arrangements for the hold spaces that are not connected with the machinery space shall be provided. Means of detecting any leakage shall be provided.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 66

Part 5 Chapter 7 Section 3

.7

7.1.3 The hold or interbarrier spaces of type A independent tank ships shall be provided with a drainage system suitable for handling liquid cargo in the event of cargo tank leakage or rupture. Such arrangements shall provide for the return of any cargo leakage to the liquid cargo piping. 7.1.4 Arrangements referred to in [7.1.3] shall be provided with a removable spool piece. 7.1.5 Ballast spaces, including wet duct keels used as ballast piping, oil fuel tanks and non-hazardous spaces, may be connected to pumps in the machinery spaces. Dry duct keels with ballast piping passing through may be connected to pumps in the machinery spaces, provided the connections are led directly to the pumps, and the discharge from the pumps is led directly overboard with no valves or manifolds in either line that could connect the line from the duct keel to lines serving non-hazardous spaces. Pump vents shall not be open to machinery spaces. Guidance note: The requirement that pump vents shall not be open to machinery spaces, applies only to pumps in the machinery spaces serving dry duct keels through which ballast piping passes. See MSC.1/Circ.1599. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.6 For ships with integral tanks such connection given in [7.1.5] between cargo area and machinery spaces is not acceptable.

8 Bow and stern loading and unloading arrangements 8.1 General requirements 8.1.1 Subject to the requirements of this paragraph [8.1] and Sec.5, cargo piping may be arranged to permit bow or stern loading and unloading. 8.1.2 Bow or stern loading and unloading lines that are led past accommodation spaces, service spaces or control stations shall not be used for the transfer of products requiring a type 1G ship. Bow or stern loading and unloading lines shall not be used for the transfer of toxic products unless specifically approved. 8.1.3 Portable arrangements are not permitted. 8.1.4 Entrances, air inlets and openings Entrances, air inlets and openings to accommodation spaces, service spaces, machinery spaces 1. and controls stations, shall not face the cargo shore connection location of bow or stern loading and unloading arrangements. They shall be located on the outboard side of the superstructure or deckhouse at a distance of at least 4 % of the length of the ship, but not less than 3 m from the end of the superstructure or deckhouse facing the cargo shore connection location of the bow or stern loading and unloading arrangements. This distance need not exceed 5 m. Air outlets are subject to the same requirements as air inlets and air intakes.

2.

Windows and sidescuttles facing the shore connection location and on the sides of the superstructure or deckhouse within the distance mentioned above shall be of the fixed (non-opening) type.

3.

In addition, during the use of the bow or stern loading and unloading arrangements, all doors, ports and other openings on the corresponding superstructure or deckhouse side shall be kept closed.

4.

Where, in the case of small ships, compliance with [2.1.4] .1 to .4 and [8.1.4] .1 to .3 is not possible, the Society may approve relaxations from the above requirements.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 67

Part 5 Chapter 7 Section 3

7.1.2 Where there is a secondary barrier, suitable drainage arrangements for dealing with any leakage into the hold or insulation spaces through the adjacent ship structure, shall be provided. The suction shall not lead to pumps inside the machinery space. Means of detecting such leakage shall be provided.

8.1.6 Fire-fighting arrangements for the bow or stern loading and unloading areas shall be in accordance with Sec.11 [3.1.1] .4 and Sec.11 [4.1.6]. 8.1.7 Means of communication between the cargo control station and the shore connection location shall be provided and, where applicable, certified for use in hazardous areas.

9 Cofferdams and pipe tunnels 9.1 General requirements 9.1.1 Cofferdams shall be of sufficient size for easy access to all parts. Minimum distance between bulkheads: 600 mm. 9.1.2 Ballast tanks will be accepted as cofferdams. 9.1.3 Pipe tunnels shall have ample space for inspection of the pipes. The pipes shall be situated as high as possible above the ship's bottom. 9.1.4 On ships with integral tanks, no connections between a pipe tunnel and the engine room either by pipes or manholes will be accepted.

10 Guard rails and bulwarks 10.1 Arrangement In the cargo area open guard rails shall normally be fitted. Plate bulwarks with a 230 mm high continuous opening at lower edge may be accepted upon consideration of the deck arrangement and probable gas accumulation.

11 Diesel engines driving emergency fire pumps or similar equipment forward of cargo area 11.1 General requirements 11.1.1 Diesel engines driving emergency fire pumps or similar equipment shall be installed in a nonhazardous area. 11.1.2 The exhaust pipe of the diesel engine shall have an effective spark arrestor and shall be led out to the atmosphere at a safe distance from hazardous areas.

12 Chain locker and windlass 12.1 General requirements 12.1.1 Chain lockers shall be arranged as non-hazardous spaces. Windlass and chain pipes shall be situated in non-hazardous areas.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 68

Part 5 Chapter 7 Section 3

8.1.5 Deck openings and air inlets and outlets to spaces within distances of 10 m from the cargo shore connection location shall be kept closed during the use of bow or stern loading or unloading arrangements.

13.1 General requirements 13.1.1 Anodes and other permanently installed equipment in tanks and cofferdams shall be securely fastened to the structure. The units and their supports shall be able to withstand sloshing in the tanks and vibratory loads as well as other loads which may be imposed in service.

14 Emergency towing 14.1 General requirements 14.1.1 Emergency towing arrangement for gas carriers of 20 000 tonnes deadweight and above shall comply with requirements in Ch.5 Sec.2 [2.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 69

Part 5 Chapter 7 Section 3

13 Anodes and other fittings in tanks and cofferdams

1 General 1.1 Definitions 1.1.1 A cold spot is a part of the hull or thermal insulation surface where a localized temperature decrease occurs with respect to the allowable minimum temperature of the hull or of its adjacent hull structure, or to design capabilities of cargo pressure/temperature control systems required in Sec.7. 1.1.2 Design vapour pressure P0 is the maximum gauge pressure, at the top of the tank, to be used in the design of the tank. 1.1.3 Design temperature for selection of materials is the minimum temperature at which cargo may be loaded or transported in the cargo tanks. See Sec.24. For ships with design temperature higher than the cargo boiling point temperature at atmospheric pressure, provisions to the satisfaction of the Society shall be made so that the tank or cargo temperature cannot be lowered below the design temperature. 1.1.4 Independent tanks are self-supporting tanks. They do not form part of the ship's hull and are not essential to the hull strength. There are three categories of independent tank, which are referred to in Sec.20, Sec.21 and Sec.22. 1.1.5 Membrane tanks are non-self-supporting tanks that consist of a thin liquid and gastight layer (membrane) supported through insulation by the adjacent hull structure. Membrane tanks are covered in Sec.23. 1.1.6 Integral tanks are tanks that form a structural part of the hull and are influenced in the same manner by the loads that stress the adjacent hull structure. Integral tanks are covered in Sec.24 [1]. 1.1.7 Semi-membrane tanks are non-self-supporting tanks in the loaded condition and consist of a layer, parts of which are supported through insulation by the adjacent hull structure. Semi-membrane tanks are covered in Sec.24 [2].

1.2 Application 1.2.1 Unless otherwise specified in Sec.20, Sec.21, Sec.22 and Sec.23, the requirements of this section shall apply to all types of tanks, including those covered in Sec.24.

2 Cargo containment 2.1 Functional requirements 2.1.1 The design life of the cargo containment system shall not be less than the design life of the ship or 25 years whichever is the larger. 2.1.2 Cargo containment systems shall be designed for North Atlantic environmental conditions and relevant long-term sea state scatter diagrams for unrestricted navigation. Lesser environmental conditions, consistent with the expected usage, may be accepted by the Society for cargo containment systems used exclusively for restricted navigation. Greater environmental conditions may be required for cargo containment systems operated in conditions more severe than the North Atlantic environment.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 70

Part 5 Chapter 7 Section 4

SECTION 4 CARGO CONTAINMENT

.1

to withstand, in the intact condition, the environmental conditions anticipated for the cargo containment system’s design life and the loading conditions appropriate for them, which include full homogeneous and partial load conditions, partial filling within defined limits and ballast voyage loads, and

.2

being appropriate for uncertainties in loads, structural modelling, fatigue, corrosion, thermal effects, material variability, ageing and construction tolerances.

2.1.4 The cargo containment system structural strength shall be assessed against failure modes, including but not limited to plastic deformation, buckling, and fatigue. The specific design conditions which shall be considered for the design of each cargo containment system are given in Sec.20 to Sec.24. The three main categories of design conditions are outlined below.

.1

Ultimate design conditions – The cargo containment system structure and its structural components shall withstand loads liable to occur during its construction, testing and anticipated use in service, without loss of structural integrity. The design shall take into account proper combinations of the following loads:

.1 .2 .3 .4 .5 .6 .7 .8 .9 .10

internal pressure external pressure dynamic loads due to the motion of the ship thermal loads sloshing loads loads corresponding to ship deflections tank and cargo weight with the corresponding reaction in way of supports insulation weight loads in way of towers and other attachments, and test loads.

.2

Fatigue design conditions – The cargo containment system structure and its structural components shall not fail under accumulated cyclic loading.

.3

The cargo containment system shall meet the following criteria:

.1

Collision – The cargo containment system shall be protectively located in accordance with Sec.2 [4.1.1] and withstand the collision loads specified in [3.5.2] without deformation of the supports, or the tank structure in way of the supports, likely to endanger the tank structure.

.2

Fire – The cargo containment systems shall sustain without rupture the rise in internal pressure specified in Sec.8 [4.1.1] under the fire scenarios envisaged therein.

.3

Flooded compartment causing buoyancy on tank – The anti-flotation arrangements shall sustain the upward force, specified in [3.5.3], and there shall be no endangering plastic deformation to the hull.

2.1.5 Measures shall be applied to ensure that scantlings required meet the structural strength provisions and be maintained throughout the design life. Measures may include, but are not limited to, material selection, coatings, corrosion additions, cathodic protection and inerting. Corrosion allowance is not required in addition to the thickness resulting from the structural analysis. However, where there is no environmental control, such as inerting around the cargo tank, or where the cargo is of a corrosive nature, the Society may require a suitable corrosion allowance. 2.1.6 An inspection/survey plan for the cargo containment system shall be developed and approved by the Society. The inspection/survey plan shall identify areas for which inspection during surveys throughout

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 71

Part 5 Chapter 7 Section 4

2.1.3 Cargo containment systems shall be designed with suitable safety margins fulfilling following criteria:

2.2 Cargo containment safety principles 2.2.1 The containment systems shall be provided with a full secondary liquid-tight barrier capable of safely containing all potential leakages through the primary barrier and, in conjunction with the thermal insulation system, of preventing lowering of the temperature of the ship structure to an unsafe level. 2.2.2 However, the size and configuration or arrangement of the secondary barrier may be reduced where an equivalent level of safety is demonstrated in accordance with the requirements of [2.2.3] to [2.2.5], as applicable. 2.2.3 Cargo containment systems for which the probability for structural failures to develop into a critical state has been determined to be extremely low, but where the possibility of leakages through the primary barrier cannot be excluded, shall be equipped with a partial secondary barrier and small leak protection system capable of safely handling and disposing of the leakages. The arrangements shall comply with the following requirements:

.1

failure developments that can be reliably detected before reaching a critical state (e.g. by gas detection or inspection) shall have a sufficiently long development time for remedial actions to be taken, and

.2

failure developments that cannot be safely detected before reaching a critical state shall have a predicted development time that is much longer than the expected lifetime of the tank.

2.2.4 No secondary barrier is required for cargo containment systems, e.g. type C independent tanks, where the probability for structural failures and leakages through the primary barrier is extremely low and can be neglected. 2.2.5 No secondary barrier is required where the cargo temperature at atmospheric pressure is at or above -10°C. 2.2.6 Leak before failure For type B-tanks it shall be documented if failure development can be safely detected by leakage detection. Leak-before-failure (LBF) is proven whether following conditions are met:

.1

A crack in the tank shell shall be shown by fracture mechanics to exhibit stable growth through the shell thickness until the crack is sufficiently large to cause a leakage likely to be detected by the gas detection system, and:

.2

Continue to grow in a stable manner for a period of at least 15 days in specified environmental conditions.

.3

The small leak protection system shall be designed to safely contain and dispose of the expected leakage rate during the 15 day period.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 72

Part 5 Chapter 7 Section 4

the cargo containment system's life, is required and, in particular, all necessary in-service survey and maintenance that was assumed when selecting cargo containment system design parameters. Cargo containment systems shall be designed, constructed and equipped to provide adequate means of access for inspection, as specified in the inspection/survey plan. Cargo containment systems, including all associated internal equipment, shall be designed and built to ensure safety during operations, inspection and maintenance, see Sec.3 [5].

2.3.1 Secondary barriers in relation to the tank types defined in Sec.20 to Sec.24 shall be provided in accordance with Table 1. Table 1 Secondary barriers in relation to tank types Cargo temperature at atmospheric pressure

-10°C and above

Below -10°C down to -55°C

Below -55°C

basic tank type

no secondary barrier required

hull may act as secondary barrier

separate secondary barrier where required 1)

Integral

tank type normally not allowed

Membrane

complete secondary barrier

Semi-membrane

complete secondary barrier

Independent — type A — type B — type C

2)

— complete secondary barrier — partial secondary barrier — no secondary barrier

Notes: 1)

A complete secondary barrier shall normally be required if cargoes with a temperature at atmospheric pressure below -10°C are permitted in accordance with Sec.24 [1.1].

2)

In the case of semi-membrane tanks that comply in all respects with the requirements applicable to type B independent tanks, except for the manner of support, the Society may, after special consideration, accept a partial secondary barrier.

2.4 Design of secondary barriers 2.4.1 Where the cargo temperature at atmospheric pressure is not below -55°C, the hull structure may act as a secondary barrier provided that following conditions are met:

.1

the hull material shall be suitable for the cargo temperature at atmospheric pressure as required by [5.1.1] .4, and

.2

the design shall be such that this temperature will not result in unacceptable hull stresses.

2.4.2 The design of the secondary barrier shall fulfil following requirements:

.1

it is capable of containing any envisaged leakage of liquid cargo for a period of 15 days, unless different criteria apply for particular voyages, taking into account the load spectrum referred to in [4.3.3] .5

.2

physical, mechanical, or operational events within the cargo tank that could cause failure of the primary barrier shall not impair the due function of the secondary barrier, or vice versa

.3

failure of a support or an attachment to the hull structure will not lead to loss of liquid tightness of both the primary and secondary barriers

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 73

Part 5 Chapter 7 Section 4

2.3 Secondary barriers in relation to tank types

it is capable of being periodically checked for its effectiveness by means acceptable to the Society. This may be by means of a visual inspection or a pressure/vacuum test or other suitable means carried out according to a documented procedure agreed with the Society Guidance note: For containment systems with glued secondary barriers testing requirements are given in [5.2.4]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

.5

.6 .7

the methods required in .4 above shall be approved by the Society and shall include, where applicable to the test procedure:

.1

details on the size of defect acceptable and the location within the secondary barrier, before its liquid tight effectiveness is compromised

.2 .3

accuracy and range of values of the proposed method for detecting defects in 1 above

.4

effects of thermal and mechanical cyclic loading on the effectiveness of the proposed test.

scaling factors to be used in determining the acceptance criteria, if full scale model testing is not undertaken and

the secondary barrier shall fulfil its functional requirements at a static angle of heel of 30° Requirements with respect to pressure and leak testing of secondary barriers will be decided in each separate case.

2.5 Partial secondary barriers and primary barrier small leak protection system 2.5.1 Partial secondary barriers as permitted in [2.2.3] shall be used with a small leak protection system and meet all the requirements in [2.4.2]. The small leak protection system shall include means to detect a leak in the primary barrier, provision such as a spray shield to deflect any liquid cargo down into the partial secondary barrier, and means to dispose of the liquid, which may be by natural evaporation. 2.5.2 The capacity of the partial secondary barrier shall be determined, based on the cargo leakage corresponding to the extent of failure resulting from the load spectrum referred to in [4.3.3] .5, after the initial detection of a primary leak. Due account may be taken of liquid evaporation, rate of leakage, pumping capacity and other relevant factors. 2.5.3 The required liquid leakage detection may be by means of liquid sensors, or by an effective use of pressure, temperature or gas detection systems, or any combination thereof.

2.6 Supporting arrangements 2.6.1 The cargo tanks shall be supported by the hull in a manner that prevents bodily movement of the tank under the static and dynamic loads defined in [3.2] to [3.5], where applicable, while allowing contraction and expansion of the tank under temperature variations and hull deflections without undue stressing of the tank and the hull. 2.6.2 The supports shall be calculated for the most probable largest severe resulting acceleration taking into account rotational as well as translational effects. This acceleration in a given direction β may be determined as shown in Figure 1. The half axes of the acceleration ellipse are determined according to [6.1.2] for all tanks except type B-tanks where accelerations from direct hydrodynamic analysis shall be applied, see Sec.20 and Sec.21. 2.6.3 For independent tanks and, where appropriate, for membrane tanks and semi-membrane tanks, provisions shall be made to key the tanks against the rotational effects referred to in [2.6.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 74

Part 5 Chapter 7 Section 4

.4

2.6.5 Supports and supporting arrangements shall withstand the loads defined in [3.3.9] and [3.5]; combination of such loads with each other or with wave-induced loads, is not required.

2.7 Associated structure and equipment 2.7.1 Cargo containment systems shall be designed for the loads imposed by associated structure and equipment. This includes pump towers, cargo domes, cargo pumps and piping, stripping pumps and piping, nitrogen piping, access hatches, ladders, piping penetrations, liquid level gauges, independent level alarm gauges, spray nozzles, and instrumentation systems (such as pressure, temperature and strain gauges).

2.8 Thermal insulation 2.8.1 Thermal insulation shall be provided as required to protect the hull from temperatures below those allowable, see [5.1.1], and limit the heat flux into the tank to the levels that can be maintained by the pressure and temperature control system applied in Sec.7. 2.8.2 In determining the insulation performance, due regard shall be given to the amount of the acceptable boil-off in association with the re-liquefaction plant on board, main propulsion machinery or other temperature control system.

3 Design loads 3.1 General 3.1.1 This section defines the design loads to be considered with regard to the requirements in [4.1], [4.2] and [4.3]. This includes:

.1 .2

load categories (permanent, functional, environmental and accidental) and the description of the loads

.3

tanks, together with their supporting structure and other fixtures, that shall be designed taking into account relevant combinations of the loads described below.

the extent to which these loads shall be considered depending on the type of tank, and is more fully detailed in the following paragraphs, and

3.2 Permanent loads 3.2.1 Gravity loads The weight of tank, thermal insulation, loads caused by towers and other attachments shall be considered. 3.2.2 Permanent external loads Gravity loads of structures and equipment acting externally on the tank shall be considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 75

Part 5 Chapter 7 Section 4

2.6.4 Anti flotation arrangements shall be provided for independent tanks and capable of withstanding the loads defined in [3.5.3] without plastic deformation likely to endanger the hull structure.

3.3.1 Loads arising from the operational use of the tank system shall be classified as functional loads. All functional loads that are essential for ensuring the integrity of the tank system, during all design conditions, shall be considered. As a minimum, the effects from the following criteria, as applicable, shall be considered when establishing functional loads:

.1 .2 .3 .4 .5 .6 .7 .8 .9

internal pressure external pressure thermally induced loads vibration interaction loads loads associated with construction and installation test loads static heel loads, and weight of cargo.

3.3.2 Internal pressure In all cases, including .2 below, P0 shall not be less than MARVS. .1

.2

For cargo tanks where there is no temperature control and where the pressure of the cargo is dictated only by the ambient temperature, Po shall not be less than the gauge vapour pressure of the cargo at a temperature of 45°C except as follows:

.1

lower values of ambient temperature may be accepted by the Society in restricted areas. Conversely, higher values of ambient temperature may be required, and

.2

for ships on voyages of restricted duration, Po may be calculated based on the actual pressure rise during the voyage, and account may be taken of any thermal insulation of the tank.

.3

Subject to special consideration by the Society and to the limitations given in Sec.20 to Sec.24, for the various tank types, a vapour pressure Ph higher than Po may be accepted for site specific conditions (harbour or other locations), where dynamic loads are reduced. Any relief valve setting resulting from this paragraph shall be recorded in the Certificate of Fitness for the Carriage of Liquefied Gases in Bulk.

.4

The internal pressure Peq results from the vapour pressure Po or Ph plus the maximum associated dynamic liquid pressure Pgd, but not including the effects of liquid sloshing loads. Unless other values are justified by independent direct calculations, guidance formulae for associated dynamic liquid pressure Pgd are given in the guidance note in [6.1.1]. For FE analyses, see the cargo containment specific Sec.20 to Sec.24.

3.3.3 External pressure External design pressure loads shall be based on the difference between the minimum internal pressure and the maximum external pressure to which any portion of the tank may be simultaneously subjected. 3.3.4 Thermally induced loads Transient thermally induced loads during cooling down periods shall be considered for tanks intended for cargo temperatures below -55°C. Stationary thermally induced loads shall be considered for cargo containment systems where the design supporting arrangements or attachments and operating temperature may give rise to significant thermal stresses, see Sec.7 [2]. 3.3.5 Vibration The potentially damaging effects of vibration on the cargo containment system shall be considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 76

Part 5 Chapter 7 Section 4

3.3 Functional loads

3.3.6 Interaction loads The static component of loads resulting from interaction between cargo containment system and the hull structure, as well as loads from associated structure and equipment, shall be considered. 3.3.7 Loads associated with construction and installation Loads or conditions associated with construction and installation, e.g. lifting, shall be considered. 3.3.8 Test loads Account shall be taken of the loads corresponding to the testing of the cargo containment system referred to in Sec.20 to Sec.24. 3.3.9 Static heel loads Loads corresponding to the most unfavourable static heel angle within the range 0° to 30° shall be considered. 3.3.10 Other loads Any other loads not specifically addressed, which could have an effect on the cargo containment system, shall be taken into account.

3.4 Environmental loads 3.4.1 Environmental loads are defined as those loads on the cargo containment system that are caused by the surrounding environment and that are not otherwise classified as a permanent, functional or accidental load. 3.4.2 Loads due to ship motion The determination of dynamic loads shall take into account the long-term distribution of ship motion .1 in irregular seas, which the ship will experience during its operating life. Account may be taken of the reduction in dynamic loads due to necessary speed reduction and variation of heading.

.2

.3 .4 .5

The ship's motion shall include surge, sway, heave, roll, pitch and yaw. The accelerations acting on tanks shall be estimated at their centre of gravity and include the following components:

.1

vertical acceleration: motion accelerations of heave, pitch and, possibly roll normal to the ship base

.2

transverse acceleration: motion accelerations of sway, yaw and roll and gravity component of roll, and

.3

longitudinal acceleration: motion accelerations of surge and pitch and gravity component of pitch.

Methods to predict accelerations due to ship motion shall be proposed and approved by the Society. Guidance formulae for acceleration components are given in [6.1.2]. Ships for restricted service may be given special consideration.

3.4.3 Dynamic interaction loads Account shall be taken of the dynamic component of loads resulting from interaction between cargo containment systems and the hull structure, including loads from associated structures and equipment.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 77

Part 5 Chapter 7 Section 4

Design of hull and cargo tanks, choice of machinery and propellers shall be aimed at keeping vibration exciting forces and vibratory stresses low. Calculations or other appropriate information pertaining to the excitation forces from machinery and propellers, may be required for membrane tanks, semi-membrane tanks, independent tanks type B, and in special cases, for independent tanks type A and C. Full-scale measurements of vibratory stresses and or frequencies may be required.

.2

When significant sloshing-induced loads are expected to be present, special tests and calculations shall be required covering the full range of intended filling levels.

3.4.5 Snow and ice loads Snow and icing shall be considered, if relevant. 3.4.6 Loads due to navigation in ice Loads due to navigation in ice shall be considered for vessels intended for such service. Guidance note: See Pt.6 Ch.6 Sec.4 for requirements for operation in ice. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.5 Accidental loads 3.5.1 Accidental loads are defined as loads that are imposed on a cargo containment system and its supporting arrangements under abnormal and unplanned conditions. 3.5.2 Collision loads Collision loads shall be determined based on the cargo containment system under fully loaded condition with an inertial force corresponding to 0.5g in the forward direction and 0.25g in the aft direction, where g is gravitational acceleration. 3.5.3 Loads due to flooding on ship For independent tanks, loads caused by the buoyancy of an empty tank in a hold space, flooded to the summer load draught, shall be considered in the design of the anti-flotation chocks and the supporting hull structure.

4 Structural integrity 4.1 General 4.1.1 The structural design shall ensure that tanks have an adequate capacity to sustain all relevant loads with an adequate margin of safety. This shall take into account the possibility of plastic deformation, buckling, fatigue and loss of liquid and gas tightness. 4.1.2 The structural integrity of cargo containment systems shall be demonstrated by compliance with Sec.20 to Sec.24, as appropriate for the cargo containment system type. 4.1.3 The structural integrity of cargo containment system types that are of novel design and differ significantly from those covered by Sec.20 to Sec.24, shall be demonstrated by compliance with Sec.24 [3] to ensure that the overall level of safety provided for in this chapter is maintained. 4.1.4 When determining the design stresses the minimum specified mechanical properties of the material, including the weld metal in the fabricated condition shall be used. For certain materials, subject to special consideration by the Society, advantage may be taken of enhanced yield strength and tensile strength at design temperatures below -105°C. However, material strength data at ambient temperature shall be applied at ambient temperature conditions, e.g. pressure testing.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 78

Part 5 Chapter 7 Section 4

3.4.4 Sloshing loads The sloshing loads on a cargo containment system and internal components shall be evaluated based .1 on allowable filling levels.

4.2.1 Analysis The design analyses shall be based on accepted principles of statics, dynamics and strength of .1 materials.

.2

Simplified methods or simplified analyses may be used to calculate the load effects, provided that they are conservative. Model tests may be used in combination with, or instead of, theoretical calculations. In cases where theoretical methods are inadequate, model or full-scale tests may be required.

.3

When determining responses to dynamic loads, the dynamic effect shall be taken into account where it may affect structural integrity.

4.2.2 Load scenarios For each location or part of the cargo containment system to be considered and for each possible .1 mode of failure to be analysed, all relevant combinations of loads that may act simultaneously shall be considered.

.2

The most unfavourable scenarios for all relevant phases during construction, handling, testing and in service and conditions shall be considered.

4.2.3 When the static and dynamic stresses are calculated separately, and unless other methods of calculation are justified, the total stresses shall be calculated according to:

where:

τxy,st , τxz,st and τyz,st are static stresses, and σx,dyn , σy,dyn , σz,dyn , τxy,dyn , τxz,dyn and τyz,dyn are dynamic stresses, σx,st, σy,st , σz,st ,

each shall be determined separately from acceleration components and hull strain components due to deflection and torsion.

4.3 Design conditions 4.3.1 General All relevant failure modes shall be considered in the design for all relevant load scenarios and design conditions. The design conditions are given in the earlier part of this section, and the load scenarios are covered by [4.2.2]. 4.3.2 Ultimate design condition Structural capacity may be determined by testing, or by analysis, taking into account both the elastic and plastic material properties, by simplified linear elastic analysis or by this chapter.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 79

Part 5 Chapter 7 Section 4

4.2 Structural analyses

.3

Plastic deformation and buckling shall be considered. Analysis shall be based on characteristic load values as follows: permanent loads

expected values

functional loads

specified values

environmental loads

for wave loads: most probable largest load encountered during 10 wave encounters, or 25 years whichever is the stricter, in North Atlantic environment.

8

For the purpose of ultimate strength assessment, the following material parameters apply: 2

.1

R eh = specified minimum yield stress at room temperature in N/mm . If the stress-strain curve does not show a defined yield stress, the 0.2 % proof stress applies.

.2

R

m

2

= specified minimum tensile strength at room temperature in N/mm .

For welded connections where under-matched welds, i.e. where the weld metal has lower tensile strength than the parent metal, are unavoidable, such as in some aluminium alloys, the respective ReH and Rm of the welds, after any applied heat treatment, shall be used. In such cases the transverse weld tensile strength shall not be less than the actual yield strength of the parent metal. If this cannot be achieved, welded structures made from such materials shall not be incorporated in cargo containment systems.

.3

.4

The above properties shall correspond to the minimum specified mechanical properties of the material, including the weld metal in the as-fabricated condition. Subject to special consideration by the Society, account may be taken of the enhanced yield stress and tensile strength at low temperature. The temperature on which the material properties are based shall be shown on the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk.

The equivalent stress von Mises σvm shall be determined by:

where:

σx σy σz τxy τxz τyz

= total normal stress in x-direction = total normal stress in y-direction = total normal stress in z-direction = total shear stress in x-y plane = total shear stress in x-z plane, and = total shear stress in y-z plane.

The above values shall be calculated as described in [4.2.3].

.5

Allowable stresses for materials other than those covered by Sec.6 shall be subject to approval by the Society in each case.

.6

Stresses may be further limited by fatigue analysis, crack propagation analysis and buckling criteria.

4.3.3 Fatigue design condition The fatigue design condition is the design condition with respect to accumulated cyclic loading. .1

.2

Where a fatigue analysis is required, the cumulative effect of the fatigue load shall comply with:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 80

Part 5 Chapter 7 Section 4

.1 .2

ni Ni

= number of stress cycles at each stress level during the life of the tank = number of cycles to fracture for the respective stress level according to the high cycle design S-N curve

n Loading = number of loading and unloading cycles during the life of the tank, not to b less than 1000. Loading and unloading cycles include a complete pressure and thermal cycle

N loading = number of loading cycles to fracture due to low cycle fatigue from loading and unloading, and

Cw

= maximum allowable cumulative fatigue damage ratio 8

The fatigue damage shall be based on the design life of the tank but not less than 10 wave encounters, or 25 years whichever is the stricter.

.3 .4

.5

Where required, the cargo containment system shall be subject to fatigue analysis, considering all fatigue loads and their appropriate combinations for the expected life of the cargo containment system. Consideration shall be given to various filling conditions.

.1

Design S-N curves used in the analysis shall be applicable to the materials and weldments, construction details, fabrication procedures and applicable state of the stress envisioned.

.2

The S-N curves shall be based on a 97.6 % probability of survival corresponding to the meanminus-two-standard-deviation curves of relevant experimental data up to final failure. Use of SN curves derived in a different way requires adjustments to the acceptable Cw values specified in .7 to .9.

Analysis shall be based on characteristic load values as follows: permanent loads

expected values

functional loads

specified values or specified history

environmental loads

expected load history, but not less than 10 cycles or 25 years whichever is the stricter, in North Atlantic environment.

8

If simplified dynamic loading spectra are used for the estimation of the fatigue life, they shall be submitted to the Society, for particular evaluation.

.6

Crack propagation

.1

Where the size of the secondary barrier is reduced, as is provided for in [2.2.3], fracture mechanics analyses of fatigue crack growth shall be carried out to determine:

.1 .2 .3 .4 .5

crack propagate on paths in the structure crack growth rate the time required for a crack to propagate to cause a leakage from the tank the size and shape of through thickness cracks, and the time required for detectable cracks to reach a critical state. The fracture mechanics are, in general, based on crack growth data taken as a mean value plus two standard deviations of the test data.

.2

In analysing crack propagation, the largest initial crack not detectable by the inspection method applied shall be assumed, taking into account the allowable non-destructive testing and visual inspection criterion, as applicable.

.3

Crack propagation analysis under the condition specified in .7: the simplified load distribution and sequence over a period of 15 days may be used. Such distributions may be obtained as

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 81

Part 5 Chapter 7 Section 4

where:

.4 .5

The arrangements shall comply with .7 to .9, as applicable.

.6

If necessary, the requirements for establishing crack sizes and crack shapes may have to be documented by means of experiments. The fracture toughness properties of the tank material and its welded joints in the thicknesses used in the design shall be well documented to permit determination of crack sizes for important parts of the tanks. The determination of crack sizes shall be performed using recognized calculation procedures which have to be approved in each case.

.7

The fracture toughness properties shall be expressed using recognized standards or practice e.g., BS 7910 Guide on the Methods for Assessing the Acceptability of Flaws in Metallic Structures.

The analysis shall establish the size and shape of possible fatigue cracks at penetration of the tank wall and during subsequent propagation as through-thickness cracks as relevant, taking into account the stress distribution in the tank wall.

Depending on material, fracture toughness properties determined for loading rates similar to those expected in the tank system may be required. The fatigue crack propagation rate properties shall be documented for the tank material and its welded joints for the relevant service conditions. These properties shall be expressed using a recognized fracture mechanics practice relating the fatigue crack propagation rate to the variation in stress intensity, ΔK, at the crack tip. The effect of stresses produced by static loads shall be taken into account when establishing the choice of fatigue crack propagation rate parameters.

.8 .7

Fracture mechanics analysis procedures are given in the rule sections for the Independent tanks of type B, Sec.20 for prismatic tanks and Sec.21 for spherical tanks.

For failures that can be reliably detected by means of leakage detection: Cw ≤ 0.5 Predicted remaining failure development time, from the point of detection of leakage till reaching a critical state, shall not be less than 15 days, unless different requirements apply for ships engaged in particular voyages.

.8

For failures that cannot be detected by leakage but that can be reliably detected at the time of inservice inspections: Cw ≤ 0.5 Predicted remaining failure development time, from the largest crack not detectable by in- service inspection methods until reaching a critical state, shall not be less than three times the inspection interval.

.9

In particular locations of the tank where effective defect or crack development detection cannot be assured, the following, more stringent, fatigue acceptance criteria shall be applied as a minimum: Cw ≤ 0.1 Predicted failure development time, from the assumed initial defect until reaching a critical state, shall not be less than three times the lifetime of the tank.

4.3.4 Accident design condition The accident design condition is a design condition for accidental loads with extremely low probability .1 of occurrence.

.2

Analysis shall be based on the characteristic values as follows: permanent loads

expected values

functional loads

specified values

environmental loads

specified values

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 82

Part 5 Chapter 7 Section 4

indicated in Figure 4. Load distribution and sequence for longer periods, such as in .8 and .9 shall be approved by the Society.

.3

specified values or expected values

Loads mentioned in [3.3.9] and [3.5] need not be combined with each other or with wave induced loads.

5 Materials and construction 5.1 Materials 5.1.1 Materials forming ship structure To determine the grade of plate and sections used in the hull structure, a temperature calculation shall .1 be performed for all tank types when the cargo temperature is below -10°C. The following assumptions shall be made in this calculation:

.1 .2

the primary barrier of all tanks shall be assumed to be at the cargo temperature

.3

for worldwide service, ambient temperatures shall be taken as 5°C for air and 0°C for seawater. Higher values may be accepted for ships operating in restricted areas and conversely, lower values may be fixed by the Society for ships trading to areas where lower temperatures are expected during the winter months

.4 .5

still air and sea water conditions shall be assumed, i.e. no adjustment for forced convection

.6

the cooling effect of the rising boil-off vapour from the leaked cargo shall be taken into account, where applicable

.7

credit for hull heating may be taken in accordance with .5, provided the heating arrangements are in compliance with .6

.8 .9

no credit shall be given for any means of heating, except as described in .5, and

in addition to .1.1, where a complete or partial secondary barrier is required, it shall be assumed to be at the cargo temperature at atmospheric pressure for any one tank only

degradation of the thermal insulation properties over the life of the ship due to factors such as thermal and mechanical ageing, compaction, ship motions and tank vibrations, as defined in [5.1.3] .6 and .7, shall be assumed

for members connecting inner and outer hulls, the mean temperature may be taken for determining the steel grade. The ambient temperatures used in the design, described in this paragraph, shall be shown in appendix to class certificate and on the International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk.

.2

The shell and deck plating of the ship and all stiffeners attached thereto shall be in accordance with Sec.6. If the calculated temperature of the material in the design condition is below -5°C due to the influence of the cargo temperature, the material shall be in accordance with Sec.6 Table 5.

.3

The materials of all other hull structures for which the calculated temperature in the design condition is below 0°C, due to the influence of cargo temperature and that do not form the secondary barrier, shall also be in accordance with Sec.6 Table 5. This includes hull structure supporting the cargo tanks, inner bottom plating, longitudinal bulkhead plating, transverse bulkhead plating, floors, webs, stringers and all attached stiffening members.

.4

The hull material forming the secondary barrier shall be in accordance with Sec.6 Table 2. Where the secondary barrier is formed by the deck or side shell plating, the material grade required by Sec.6 Table 2 shall be carried into the adjacent deck or side shell plating, where applicable, to a suitable extent.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 83

Part 5 Chapter 7 Section 4

accidental loads

.6

Means of heating structural materials may be used to ensure that the material temperature does not fall below the minimum allowed for the grade of material specified in Sec.6 Table 5. In the calculations required in .1, credit for such heating may be taken in accordance with the following:

.1 .2

for any transverse hull structure

.3

as an alternative to .2, for longitudinal bulkhead between cargo tanks, credit may be taken for heating provided the material remain suitable for a minimum design temperature of -30°C, or a temperature 30°C lower than that determined by .1 with the heating considered, whichever is less. In this case, the ship's longitudinal strength shall comply with SOLAS regulation II-1/3-1 for both when those bulkhead(s) are considered effective and not. An additional risk assessment may be required by the Society.

for longitudinal hull structure referred to in .2 and .3 where colder ambient temperatures are specified, provided the material remains suitable for the ambient temperature conditions of +5°C for air and 0°C for seawater with no credit taken in the calculations for heating, and

The means of heating referred to in .5 shall comply with the following requirements:

.1

the heating system shall be arranged so that, in the event of failure in any part of the system, standby heating can be maintained equal to not less than 100 % of the theoretical heat requirement

.2

the heating system shall be considered as an essential auxiliary. All electrical components of at least one of the systems provided in accordance with .5.1 shall be supplied from the emergency source of electrical power, and

.3

the design and construction of the heating system shall be included in the approval of the containment system by the Society.

5.1.2 Materials of primary and secondary barriers Metallic materials used in the construction of primary and secondary barriers not forming the hull, shall .1 be suitable for the design loads that they may be subjected to, and be in accordance with, Sec.6 Table 1, Sec.6 Table 2 or Sec.6 Table 3.

.2

Materials, either non-metallic or metallic but not covered by Sec.6 Table 1, Sec.6 Table 2 or Sec.6 Table 3, used in the primary and secondary barriers may be approved by the Society, considering the design loads that they may be subjected to, their properties and their intended use, may be approved by the Society, considering the design loads that they may be subjected to, their properties and their intended use.

.3

Where non-metallic materials, including composites, are used for or incorporated in the primary or secondary barriers, they shall be tested for the following properties, as applicable, to ensure that they are adequate for the intended service:

.1 .2 .3 .4 .5 .6 .7 .8 .9

compatibility with the cargoes ageing mechanical properties thermal expansion and contraction abrasion cohesion resistance to vibrations resistance to fire and flame spread, and resistance to fatigue failure and crack propagation.

.4

The above properties, where applicable, shall be tested for the range between the expected maximum temperature in service and 5°C below the minimum design temperature, but not lower than -196°C.

.5

Non-metallic materials

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 84

Part 5 Chapter 7 Section 4

.5

Where non-metallic materials, including composites, are used for the primary and secondary barriers, the joining processes shall also be tested as described in .3.

.2

Guidance on the use of non-metallic materials in the construction of primary and secondary barriers is provided in App.A.

Consideration may be given to the use of materials in the primary and secondary barrier, which are not resistant to fire and flame spread, provided they are protected by a suitable system such as a permanent inert gas environment, or are provided with a fire-retardant barrier.

5.1.3 Thermal insulation and other materials used in cargo containment systems Load-bearing thermal insulation and other materials used in cargo containment systems shall be .1 suitable for the design loads.

.2

Thermal insulation and other materials used in cargo containment systems shall have the following properties, as applicable, to ensure that they are adequate for the intended service:

.1 .2 .3 .4 .5 .6 .7 .8

compatibility with the cargoes

.9 .10 .11 .12 .13 .14

abrasion

solubility in the cargo absorption of the cargo shrinkage ageing closed cell content density mechanical properties, to the extent that they are subjected to cargo and other loading effects, thermal expansion and contraction cohesion thermal conductivity resistance to vibrations resistance to fire and flame spread, and resistance to fatigue failure and crack propagation.

.3

The above properties, where applicable, shall be tested for the range between the expected maximum temperature in service and 5°C below the minimum design temperature, but not lower than -196°C.

.4

Due to location or environmental conditions, thermal insulation materials shall have suitable properties of resistance to fire and flame spread and shall be adequately protected against penetration of water vapour and mechanical damage. Where the thermal insulation is located on or above the exposed deck, and in way of tank cover penetrations, it shall have suitable fire resistance properties in accordance with recognized standards or be covered with a material having low flame-spread characteristics and forming an efficient approved vapour seal.

.5

Thermal insulation that does not meet recognized standards for fire resistance may be used in hold spaces that are not kept permanently inerted, provided its surfaces are covered with material with low flame-spread characteristics and that forms an efficient approved vapour seal. Guidance note: Organic foams should be of a flame-retarding quality, i.e. with low ignition point and low flame-spread properties. Testing shall be carried out in accordance with a recognised standard, e.g. DIN 4102 IB2, or equivalent. The test method chosen shall be suitable for the type of foam in question. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

.6

Testing for thermal conductivity of thermal insulation shall be carried out on suitably aged samples.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 85

Part 5 Chapter 7 Section 4

.6

.1

Where powder or granulated thermal insulation is used, measures shall be taken to reduce compaction in service and to maintain the required thermal conductivity and also prevent any undue increase of pressure on the cargo containment system.

5.2 Construction processes 5.2.1 Weld joint design All welded joints of the shells of independent tanks shall be of the in-plane butt weld full penetration .1 type. For dome-to-shell connections only, tee welds of the full penetration type may be used depending on the results of the tests carried out at the approval of the welding procedure. Except for small penetrations on domes, nozzle welds shall also be designed with full penetration.

.2

.3

Welding joint details for type C independent tanks, and for the liquid-tight primary barriers of type B independent tanks primarily constructed of curved surfaces, shall be as follows:

.1

all longitudinal and circumferential joints shall be of butt welded, full penetration, double vee or single vee type. Full penetration butt welds shall be obtained by double welding or by the use of backing rings. If used, backing rings shall be removed except from very small process pressure vessels. Other edge preparations may be permitted, depending on the results of the tests carried out at the approval of the welding procedure, and

.2

the bevel preparation of the joints between the tank body and domes and between domes and relevant fittings shall be designed according to the Society’s requirements for welding, e.g. Pt.4 Ch.7. All welds connecting nozzles, domes or other penetrations of the vessel and all welds connecting flanges to the vessel or nozzles shall be full penetration welds. shall be designed according to the Society’s requirements for welding, e.g. Pt.4 Ch.7. All welds connecting nozzles, domes or other penetrations of the vessel and all welds connecting flanges to the vessel or nozzles shall be full penetration welds.

Where applicable, all the construction processes and testing, except that specified in [5.2.3], shall be done in accordance with the applicable provisions of Sec.6.

5.2.2 Design for gluing and other joining processes The design of the joint to be glued, or joined by some other process except welding, shall take account of the strength characteristics of the joining process. 5.2.3 Testing All cargo tanks and process pressure vessels shall be subjected to hydrostatic or hydropneumatic .1 pressure testing in accordance with Sec.20 to Sec.24, as applicable for the tank type.

.2

All tanks shall be subject to a tightness test which may be performed in combination with the pressure test referred to in .1.

.3

Requirements with respect to inspection of secondary barriers shall be decided by the Society in each case, taking into account the accessibility of the barrier. See also [2.4.2].

.4

The Society may require that for ships fitted with novel type B independent tanks, or tanks designed according to Sec.24 [3] at least one prototype tank and its supporting structures shall be instrumented with strain gauges or other suitable equipment to confirm stress levels. Similar instrumentation may be required for type C independent tanks, depending on their configuration and on the arrangement of their supports and attachments.

.5

The overall performance of the cargo containment system shall be verified for compliance with the design parameters during the first full loading and discharging of the cargo, in accordance with the survey procedure of the Society. Records of the performance of the components and equipment essential to verify the design parameters, shall be maintained and be available to the Society.

.6

Heating arrangements, if fitted in accordance with [5.1.1] .5 and .6, shall be tested for required heat output and heat distribution.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 86

Part 5 Chapter 7 Section 4

.7

The cargo containment system shall be inspected for cold spots during, or immediately following, the first loaded voyage. Inspection of the integrity of thermal insulation surfaces that cannot be visually checked shall be carried out in accordance with recognized standards.

5.2.4 Membrane containment testing requirements Following testing applies:

.1

For membrane and semi-membrane tanks systems, inspection and testing shall be carried out in accordance with programmes specially prepared in accordance with an approved method for the actual tank system.

.2

For membrane containment systems a tightness test of the primary and secondary barrier shall be carried out in accordance with the system designers' procedures and acceptance criteria as approved. Low differential pressure tests may be used for monitoring the cargo containment system performance, but are not considered an acceptable test for the tightness of the secondary barrier.

.3

For membrane containment systems with glued secondary barriers if the designer's threshold values are exceeded, an investigation shall be carried out and additional testing such as thermographic or acoustic emissions testing should be carried out.

.4 .5

The values recorded should be used as reference for future assessment of secondary barrier tightness. For containment systems with welded metallic secondary barriers, a tightness test after initial cool down is not required. Guidance note: With reference to IACS UI GC12. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.3 Welding procedure tests 5.3.1 Cargo tanks and cargo process pressure vessels The requirements for welding procedure tests for cargo tanks and cargo process pressure vessels are given in Pt.2 Ch.4 Sec.5. 5.3.2 Secondary barriers Welding procedure tests are required for secondary barriers and shall be similar to those required for cargo tanks.

5.4 Welding production tests 5.4.1 General Weld production tests shall be carried out to the extent given in [5.4.2] for the different types of tanks. .1 The test requirements are given in [5.4.4].

.2

For all cargo process pressure vessels and cargo tanks except integral and membrane tanks, production tests are generally to be performed for approximately each 50 m of butt weld joints and shall be representative of each welding position and plate thickness.

.3

For secondary barriers, the same type production tests as required for primary tanks shall be performed, except that the number of tests may be reduced subject to agreement with the Society.

.4

Tests other than those specified in [5.4.2], may be required for cargo tanks or secondary barriers at the discretion of the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 87

Part 5 Chapter 7 Section 4

.7

Two bend tests, macro etching and when required for procedure tests, one set of three Charpy V-notch tests shall be made for each 50 m of weld. The Charpy V-notch tests shall be made with specimen having the notch alternately located in the centre of the weld and in the heat-affected zone (most critical location based on procedure qualification results). If only one production test is required, Charpy V-notch tests shall be made for both centre of weld and heat-affected zone. For austenitic stainless steel, all notches shall be in the centre of the weld.

.2

For independent tanks type C and cargo process pressure vessels, transverse weld tensile tests are required in addition to those tests listed in .1.

.3

Production tests for integral and membrane tanks will be dealt with in each separate case.

5.4.3 Preparation of production weld test One production weld test consists of two plates which shall be cut from the plate or the plates from .1 which the tank or pressure vessel shall be made. The plates shall be well fastened to the tank material and have sufficient dimensions to give cooling conditions as far as possible the same as for the production welding. Each plate is at least to be 150 mm x 300 mm. The test pieces shall not be detached from the shell plate until they have been properly marked and stamped by the surveyor.

.2

The two halves of the test assembly shall be tack welded to the tank or pressure vessel in such a manner that the weld of the test assembly forms a direct continuation of the joints in the product. The main rolling direction for the plates in the production weld test shall be parallel to the main rolling direction for the tank material at the place where the production weld test is situated. The weld in the test assembly shall be laid at the same time as the weld in the product, by the same welder, and the same welding parameters shall be used.

.3

If the production weld test cannot be made as a direct continuation of the weld in the tank or pressure vessel (e.g. a circumferential joint) it is, as far as possible, to be similar to the weld in the product.

.4 .5

The production weld test shall be heat-treated as the product. The weld reinforcement shall be machined flush with the plate surface on both sides of the test assembly.

5.4.4 Test requirements The dimensions of test pieces shall be as required for the welding procedure test detailed in Pt.2 Ch.4 .1 Sec.5.

.2

Test requirements are given in Pt.2 Ch.4 Sec.5.

5.5 Requirements for weld types and non-destructive testing 5.5.1 General Non-destructive testing, NDT, shall be performed in accordance with approved procedures. All test procedures shall be in accordance with recognised standards. Basic requirements are given in Pt.2 Ch.4 Sec.7. 5.5.2 Extent of testing The requirements to weld type and extent of non-destructive testing are given in Table 2. .1

.2

The repair of defects revealed during non-destructive testing shall be carried out according to agreement with the surveyor. All such weld repairs shall be inspected using the relevant testing method. If defects are detected, the extent of testing shall be increased to the surveyor's satisfaction.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 88

Part 5 Chapter 7 Section 4

5.4.2 Extent of testing For independent tanks types A and B and semi-membrane tanks, the production tests shall include the .1 following tests:

When random radiographic testing is performed and the radiograph reveals unacceptable defects, two further exposures shall be made, preferably one on each side of the initial one.

.4

When two or more radiographs (including possible additional ones) of the same weld reveal an unacceptable defect level, the entire length of the weld in question shall be radiographed.

5.5.3 Acceptance criteria The quality of the welds in aluminium shall comply with ISO 10042 quality level B, and the quality of the welds in steel shall comply with ISO 5817 quality level B. Table 2 Requirements for tank welds and non-destructive testing Non-destructive testing Tank type

Weld type requirement

Integral

full penetration

Membrane

subject to special consideration

Semimembrane

as for independent tanks or for membrane tanks as appropriate

radiography

ultrasonic testing surface crack detection

special weld inspection procedures and acceptable standards shall be submitted by the designers for approval radiography: a)

cargo tank design temperature lower than 20°C all full penetration welds of the shell plating 100%

b)

Independent, type A

Independent, type B

For dome to shell connections, tee welds of the full penetration type are acceptable. All welded joints of the shell shall be of the butt weld full penetration type. The same applies to the joints of face plates and web plates of girders and stiffening rings. Except for small penetrations on domes, nozzle welds are also generally to be designed with full penetration. For tank type C, see also Sec.22 [8.1.2].

Independent, type C

cargo tank design temperature higher than 20°C all full penetration welds in way of intersections and at least 10% of the remaining full penetration welds of tank shell

c)

butt welds of face plates and web plates of girders, stiffening rings etc. shall be radiographed as considered necessary.

radiography: a)

all butt welds in shell plates 100%

b)

butt welds of face plates and web plates of girders, stiffening rings etc. shall be radiographed as considered necessary.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

ultrasonic testing: — reinforcement rings around holes 100%. surface crack detection: — all butt welds in shell 10% — reinforcement rings around holes, nozzles etc. 100%. The remaining tank structure including the welding of girders, stiffening rings and other fittings and attachments, shall be examined by ultrasonic and surface crack detection as considered necessary.

Page 89

Part 5 Chapter 7 Section 4

.3

Weld type requirement

Secondary barriers

radiography

ultrasonic testing surface crack detection

radiography: when the outer shell of the hull is part of the secondary barrier, intersection of all vertical butt welds and seams in the side shell shall be tested. Where the sheer strake forms a part of the secondary barrier, all vertical butt welds in the sheer strake shall be tested. SeePt.2 Ch.4 Sec.7.

surface crack detection: See Pt.2 Ch.4 Sec.7.

6 Guidance 6.1 Guidance for section 4 6.1.1 Guidance to detailed calculation of internal pressure for quasi-static design purpose This section provides guidance for the calculation of the associated dynamic liquid pressure for the .1 purpose of quasi-static design calculations. This pressure may be used for determining the internal pressure referred to in [3.3.2] .4, where:

.2

.1

(Pgd)max , in MPa, is the associated liquid pressure determined using the maximum design accelerations.

.2

(Pgd site)max , in MPa, is the associated liquid pressure determined using site specific accelerations.

.3

Peq should be the greater of Peq1 and Peq2 calculated as follows: P

eq1

= Po + (Pgd)max,

P

eq2

= Ph + (Pgdsite)max.

The internal liquid pressures are those created by the resulting acceleration of the centre of gravity of the cargo due to the motions of the ship referred to in [3.4.2]. The value of internal liquid pressure Pgd , in MPa, resulting from combined effects of gravity and dynamic accelerations should be calculated as follows:

where:

αβ

= dimensionless acceleration, i.e. relative to the acceleration of gravity, resulting from gravitational and dynamic loads, in an arbitrary direction, see Figure 1 For large tanks an acceleration ellipsoid, taking account of transverse, vertical and longitudinal accelerations, should be used. 3

ρ

= maximum cargo density in kg/m at the design temperature

Zβ

= largest liquid height in m above the point where the pressure shall be determined measured from the tank shell in the β direction, see Figure 2. Tank domes considered to be part of the

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 90

Part 5 Chapter 7 Section 4

Non-destructive testing Tank type

with:

Vt FL

= tank volume without any domes, and = filling limit according to Sec.15. The direction that gives the maximum value (Pgd)max or (Pgdsite)max should be considered. The above formula applies only to full tanks.

6.1.2 Guidance formulae for acceleration components

.1

The following formulae are given as guidance for the components of acceleration due to ship's motions -8 corresponding to a probability level of 10 in the North Atlantic and apply to ships with a length exceeding 50 m and at or near their service speed: - Vertical acceleration as defined in [3.4.2]:

— Transverse acceleration as defined in [3.4.2]:

— Longitudinal acceleration as defined in [3.4.2]:

where:

L

= rule length in m of the ship for determination of scantlings as defined in Pt.3 Ch.1 Sec.4

CB B x

= block coefficient as defined in Pt.3 Ch.1 Sec.4

y

= transverse distance in m from centreline to the centre of gravity of the tank with contents, and

z

= vertical distance in m from the ship's actual waterline to the centre gravity of tank with contents; z is positive above and negative below the waterline.

K

= 1 in general. For particular loading conditions and hull forms, determination of K according to the formula below maybe necessary

= greatest moulded breadth in m of the ship as defined in Pt.3 Ch.1 Sec.4 = longitudinal distance in m from amidships to the centre of gravity of the tank with contents. x is positive forward of amidships, negative aft of amidships

K = max(13 GM/B;1.0), where GM = metacentric height in m

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 91

Part 5 Chapter 7 Section 4

accepted total tank volume shall be taken into account when determining Zb, unless the total volume of tank domes Vd does not exceed the following value:

= service speed in knots = maximum dimensionless accelerations, i.e. relative to the acceleration of gravity, in the respective directions. They are considered as acting separately for calculation purposes, and az does not include the component due to the static weight, ay includes the component due to the static weight in the transverse direction due to rolling and ax includes the component due to the static weight in the longitudinal direction due to pitching. The accelerations derived from the above formulae are applicable only to ships at or near their service speed, not while at anchor or otherwise near stationary in exposed locations.

6.1.3 Stress categories For the purpose of stress evaluation, stress categories are defined in this section as follows. .1

.2 .3

Normal stress is the component of stress normal to the plane of reference.

.4

Bending stress is the variable stress across the thickness of the section under consideration, after the subtraction of the membrane stress.

.5 .6

Shear stress is the component of the stress acting in the plane of reference.

.7

Primary general membrane stress is a primary membrane stress that is so distributed in the structure that no redistribution of load occurs as a result of yielding. distributed in the structure so that no redistribution of load occurs as a result of yielding.

.8

Primary local membrane stress arises where a membrane stress produced by pressure or other mechanical loading and associated with a primary or a discontinuity effect produces excessive distortion in the transfer of loads for other portions of the structure. Such a stress is classified as a primary local membrane stress, although it has some characteristics of a secondary stress. A stress region may be considered as local, if:

Membrane stress is the component of normal stress that is uniformly distributed and equal to the average value of the stress across the thickness of the section under consideration.

Primary stress is a stress produced by the imposed loading, which is necessary to balance the external forces and moments. The basic characteristic of a primary stress is that it is not self-limiting. Primary stresses that considerably exceed the yield strength will result in failure or at least in gross deformations.

where:

.9

S1 S2

= distance, in mm, in the meridional direction over which the equivalent stress exceeds 1.1f

R t

= mean radius of the vessel in mm

f

= allowable primary general membrane stress in N/mm .

= distance, in mm, in the meridional direction to another region where the limits for primary general membrane stress are exceeded = net wall thickness of the vessel at the location where the primary general membrane stress limit is exceeded, in mm, and 2

Secondary stress is a normal stress or shear stress developed by constraints of adjacent parts or by self-constraint of a structure. The basic characteristic of a secondary stress is that it is self-limiting. Local yielding and minor distortions can satisfy the conditions that cause the stress to occur.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 92

Part 5 Chapter 7 Section 4

V a x, a y, a z

Peak stress: the basic characteristic of a peak stress is that it does not cause any noticeable distortion and is objectionable only as a possible source of a fatigue crack or a brittle fracture.

.11

Thermal stress: a self-balancing stress produced by a non-uniform distribution of temperature or by differing thermal coefficient of expansion. Thermal stresses may be divided into two types:

.1

General thermal stress which is associated with distortion of the structure in which it occurs. General thermal stresses are classified as secondary stresses.

.2

Local thermal stress which is associated with almost complete suppression of the differential expansion and thus produces no significant distortion. Such stresses may be classified as local stresses and need only to be considered from a fatigue standpoint.

Guidance note: Examples of local thermal stresses are: Stress from radial temperature gradient in a cylindrical or spherical shell, stress in a cladding material which has a coefficient of expansion different from that of the base material, stress in a small cold point in a vessel wall. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Figure 1 Acceleration ellipsoid

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 93

Part 5 Chapter 7 Section 4

.10

Part 5 Chapter 7 Section 4 Figure 2 Determination of internal pressure heads

Figure 3 Determination of liquid height Zb for points 1, 2 and 3

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 94

Part 5 Chapter 7 Section 4 Figure 4 Simplified load distribution

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 95

1 General 1.1 General requirements 1.1.1 The requirements of this section shall apply to products and process piping, including vapour piping, gas fuel piping and vent lines of safety valves or similar piping. Auxiliary piping systems not containing cargo are exempt from the general requirements of this section. The requirements of this section are additional to those of Pt.4. Guidance note: Requirements for auxiliary piping systems not containing cargo are given in Pt.4 Ch.6. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.2 The requirements for type C independent tanks provided in Sec.4 may also apply to process pressure vessels. If so required, the term pressure vessels as used in Sec.4, covers both type C independent tanks and process pressure vessels. 1.1.3 Process pressure vessels include surge tanks, heat exchanges and accumulators that store or treat liquid or vapour cargo, see [13.6]. 1.1.4 The temperature in a steam pipe and any other hot pipeline shall not exceed 220°C, or be at least 40°C lower than the auto ignition temperature for the products intended to be carried, in hazardous space or area, or in any non-hazardous area protected by mechanical ventilation. 1.1.5 Pipes to engine or boiler rooms shall not pass through hold spaces serving as secondary barriers. 1.1.6 All normally dry spaces (not served by ballast, fuel or cargo system) within the cargo area, shall be fitted with bilge or drain arrangements. Spaces not accessible at all times shall have sounding pipes.

2 System requirements 2.1 General requirements 2.1.1 The cargo handling and cargo control systems shall be designed taking into account the following:

.1 .2 .3 .4 .5

prevention of an abnormal condition escalating to a release of liquid or vapour cargo the safe collection and disposal of cargo fluids released prevention of the formation of flammable mixtures prevention of ignition of flammable liquids or gases and vapours released, and limiting the exposure of personnel to fire and other hazards.

2.2 General arrangements 2.2.1 Any piping system that may contain cargo liquid or vapour shall fulfil following requirements:

.1

Be segregated from other piping systems, except where interconnections are required for cargo related operations such as purging, gas-freeing or inerting. The requirements of Sec.9 [1.4.4] shall be taken

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 96

Part 5 Chapter 7 Section 5

SECTION 5 PROCESS PRESSURE VESSELS AND LIQUIDS, VAPOUR AND PRESSURE PIPING SYSTEMS

.2

Except as provided in Sec.16, not pass through any accommodation space, service space or control station or through a machinery space other than a cargo machinery space.

.3

Be connected to the cargo containment system directly from the weather decks except where pipes installed in a vertical trunkway or equivalent are used to traverse void spaces above a cargo containment system and except where pipes for drainage, venting or purging traverse cofferdams.

.4

Be located in the cargo area above the weather deck except for bow or stern loading and unloading arrangements in accordance with Sec.3 [8], emergency cargo jettisoning piping systems in accordance with [3.1], turret compartment systems in accordance with [3.3] and except in accordance with Sec.16, and

.5

be located inboard of the transverse tank location requirements of Sec.2 [4.1], except for athwartship shore connection piping not subject to internal pressure at sea or emergency cargo jettisoning piping systems.

2.2.2 Suitable means shall be provided to relieve the pressure and remove liquid cargo from loading and discharging crossover headers; likewise, any piping between the outermost manifold valves and loading arms or cargo hoses to the cargo tanks, or other suitable location, prior to disconnection. 2.2.3 Piping systems carrying fluids for direct heating or cooling of cargo, shall not be led outside the cargo area, unless a suitable means is provided to prevent or detect the migration of cargo vapour outside the cargo area, see also Sec.13 [6.1.2] .6. 2.2.4 Relief valves discharging liquid cargo from the piping system shall discharge into the cargo tanks. Alternatively, they may discharge to the cargo vent mast, if means are provided to detect and dispose any liquid cargo that may flow into the vent system. Where required to prevent overpressure in downstream piping, relief valves on cargo pumps shall discharge to the pump suction. 2.2.5 All pipes shall be mounted in such a way as to minimize the risk of fatigue failure due to temperature variations or to deflections of the hull girder in a seaway. If necessary, they shall be equipped with expansion bends. Use of expansion bellows will be especially considered. Slide type expansion joints will not be accepted outside of cargo tanks. If necessary, expansion joints shall be protected against icing. 2.2.6 Means for effective drainage and gas-freeing of the cargo piping systems shall be provided.

3 Arrangements for cargo piping outside the cargo area 3.1 Emergency cargo jettisoning 3.1.1 If fitted, an emergency cargo jettisoning piping system shall comply with [2.2], as appropriate, and may be led aft, external to accommodation spaces, service spaces, control stations or machinery spaces, but shall not pass through them. If an emergency cargo jettisoning piping system is permanently installed, a suitable means of isolating the piping system from the cargo piping shall be provided within the cargo area.

3.2 Bow and stern loading arrangements 3.2.1 Subject to approval of the Society and by the requirements of Sec.3 [8], this section and [10.1], cargo piping may be arranged to permit bow or stern loading and unloading. 3.2.2 Arrangements shall be made to allow such piping to be purged and gas-freed after use. When not in use, the spool pieces shall be removed and the pipe ends shall be blank-flanged. The vent pipes connected with the purge shall be located in the cargo area.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 97

Part 5 Chapter 7 Section 5

into account with regard to preventing back-flow of cargo. In such cases, precautions shall be taken to ensure that cargo or cargo vapour cannot enter other piping systems through the interconnections.

3.3.1 For the transfer of liquid or vapour cargo through an internal turret arrangement located outside the cargo area, the piping serving this purpose shall comply with [2.2], as applicable, [10.2] and following requirements:

.1 .2 .3

piping shall be located above the weather deck except for the connection to the turret portable arrangements shall not be permitted, and arrangements shall be made to allow such piping to be purged and gas-freed after use. When not in use, the spool pieces for isolation from the cargo piping shall be removed and the pipe ends blankflanged. The vent pipes connected with the purge shall be located in the cargo area.

3.4 Gas fuel piping systems 3.4.1 Gas fuel piping in machinery spaces shall comply with all applicable parts of this section in addition to the requirements of Sec.16.

4 Design pressure 4.1 Minimum design pressure for piping, piping systems and components 4.1.1 The design pressure Po, used to determine minimum scantlings of piping and piping system components, shall be not less than the maximum gauge pressure to which the system may be subjected in service. The minimum design pressure used shall not be less than 1 MPa, except for: open-ended lines or pressure relief valve discharge lines, where it shall be not less than the lower of 0.5 MPa, or 10 times the relief valve set pressure. 4.1.2 The greatest of the following design conditions shall be used for piping, piping systems and components, based on the cargoes being carried:

.1

for vapour piping systems or components that may be separated from their relief valves and which may contain some liquid: the saturated vapour pressure at a design temperature of 45°C. Higher or lower values may be used if agreed upon by the Society, see Sec.4 [3.3.2] .2, or

.2

for systems or components that may be separated from their relief valves and which contain only vapour at all times: the superheated vapour pressure at 45°C. Higher or lower values may be used if agreed upon by the Society, see Sec.4 [3.3.2] .2; assuming an initial condition of saturated vapour in the system at the system operating pressure and temperature, or

.3 .4 .5

the MARVS of the cargo tanks and cargo processing systems, or the pressure setting of the associated pump or compressor discharge relief valve, or the maximum total discharge or loading head of the cargo piping system considering all possible pumping arrangements or the relief valve setting on a pipeline system. Guidance note: Note minimum design pressure is given in [4.1.1]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.3 Those parts of the liquid piping systems that may be subjected to surge pressures shall be designed to withstand this pressure.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 98

Part 5 Chapter 7 Section 5

3.3 Turret compartment transfer systems

5 Cargo system valve requirements 5.1 General requirements 5.1.1 Every cargo tank and piping system shall be fitted with manually operated valves for isolation purposes as specified in this section. 5.1.2 In addition, remotely operated valves shall also be fitted, as appropriate, as part of the emergency shutdown system (ESD). The purpose of this ESD system is to stop cargo flow or leakage in the event of an emergency when cargo liquid or vapour transfer is in progress. The ESD system is intended to return the cargo system to a safe static condition so that any remedial action can be taken. Due regard shall be given in the design of the ESD system to avoid the generation of surge pressures within the cargo transfer pipework. The equipment that shall be shut down on activation of ESD includes: manifold valves during loading or discharge, any pump or compressor, etc., transferring cargo internally or externally (e.g. to shore or another ship/barge) plus cargo tank valves, if the MARVS exceeds 0.07 MPa.

5.2 Cargo tank connections 5.2.1 All liquid and vapour connections, except for safety relief valves and liquid level gauging devices, shall have shut-off valves located as close to the tank as practicable. These valves shall provide full closure and shall be capable of local manual operation; they may also be capable of remote operation. 5.2.2 For cargo tanks with a MARVS exceeding 0.07 MPa, the above connections shall also be equipped with remotely controlled ESD valves. These valves shall be located as close to the tank as practicable. A single valve may be substituted for the two separate valves provided the valve complies with the requirements of Sec.18 [2.2] and provides full closure of the line. 5.2.3 All connections to independent tanks are normally to be mounted above the highest liquid level in the tanks and in the open air above the weather deck. 5.2.4 When the design temperature of cargo pipes is below -55°C, the connections to the tank shall be designed so as to reduce thermal stresses at cooling-down periods.

5.3 Cargo manifold connections 5.3.1 One remotely controlled ESD valve complying with Sec.18 [2.2] shall be provided at each cargo transfer connection in use, in order to stop liquid and vapour transfer to or from the ship. Transfer connections not in use shall be isolated with suitable blank flanges. 5.3.2 If the cargo tank MARVS exceeds 0.07 MPa, an additional manual valve shall be provided for each transfer connection in use, and may be inboard or outboard of the ESD valve to suit the ship's design. 5.3.3 Excess flow valves may be used in lieu of ESD valves if the diameter of the pipe protected does not exceed 50 mm. Excess flow valves shall close automatically at the rated closing flow of vapour or liquid as specified by the manufacturer. The piping including fittings, valves and appurtenances protected by an excess flow valve shall have a capacity greater than the rated closing flow of the excess flow valve. Excess flow

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 99

Part 5 Chapter 7 Section 5

4.1.4 The design pressure of the outer pipe or duct of gas fuel systems shall not be less than the maximum working pressure of the inner gas pipe. Alternatively, for gas fuel piping systems with a working pressure greater than 1 MPa, the design pressure of the outer duct shall not be less than the maximum built-up pressure arising in the annular space considering the local instantaneous peak pressure in way of any rupture and the ventilation arrangements.

5.3.4 Cargo tank connections for gauging or measuring devices need not be equipped with excess flow valves or ESD valves, provided that the devices are constructed so that the outward flow of tank contents cannot exceed that passed by a 1.5 mm diameter circular hole. 5.3.5 All pipelines or components which may be isolated in a liquid full condition, shall be protected with relief valves for thermal expansion and evaporation, unless pipe is designed for the saturation pressure corresponding to the temperature of +45°C of any cargo to be transported. Pressure relief valves as mentioned above, shall be set to open at a pressure of 1.0 to 1.1 times the design pressure of the pipes. 3

5.3.6 All pipelines or components with entrapped liquid volume of more than 0.05 m and that are designed to be isolated automatically at the occurrence of fire, shall be provided with pressure release valve (PRV) sized for a fire condition. Guidance note: Note that this requirement is applicable for remotely operated valves controlled by the ESD system. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6 Cargo transfer arrangements 6.1 General 6.1.1 Where cargo transfer is by means of cargo pumps that are not accessible for repair with the tanks in service, at least two separate means shall be provided to transfer cargo from each cargo tank and the design shall be such that failure of one cargo pump or means of transfer will not prevent the cargo transfer by another pump or pumps, or other cargo transfer means. 6.1.2 The procedure for transfer of cargo by gas pressurization shall preclude lifting of the relief valves during such transfer. Gas pressurization may be accepted as a means of transfer of cargo for those tanks where the design factor of safety is not reduced under the conditions prevailing during the cargo transfer operation. If the cargo tank relief valves or set pressure are changed for this purpose, as it is permitted in accordance with Sec.8 [2.2.4] and Sec.8 [2.2.5], the new set pressure is not to exceed Ph as is defined in Sec.4 [3.3]. 6.1.3 Sprayers or similar devices shall be fitted for even cooling of the cargo tanks.

6.2 Vapour return connections 6.2.1 Connections for vapour return to the shore installations shall be provided.

6.3 Cargo tank vent piping systems 6.3.1 The pressure relief system shall be connected to a vent piping system designed to minimize the possibility of cargo vapour accumulating on the decks, or entering accommodation spaces, service spaces, control stations and machinery spaces, or other spaces where it may create a dangerous condition.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 100

Part 5 Chapter 7 Section 5

valves may be designed with a bypass not exceeding the area of a 1.0 mm diameter circular opening to allow equalization of pressure after a shutdown activation.

6.4.1 Connections to cargo piping systems for taking cargo liquid samples shall be clearly marked and shall be designed to minimize the release of cargo vapours. For vessels permitted to carry cargoes noted as toxic in Sec.19, the sampling system shall be of a closed loop design to ensure that cargo liquid and vapour are not vented to atmosphere. 6.4.2 Liquid sampling systems shall be provided with two valves on the sample inlet. One of these valves shall be of the multi-turn type to avoid accidental opening, and shall be spaced far enough apart to ensure that they can isolate the line if there is blockage, by ice or hydrates for example. 6.4.3 On closed loop systems, the valves on the return pipe shall also comply with [6.4.2]. 6.4.4 The connection to the sample container shall comply with recognized standards and be supported so as to be able to support the weight of a sample container. Threaded connections shall be tack-welded, or otherwise locked, to prevent them being unscrewed during the normal connection and disconnection of sample containers. The sample connection shall be fitted with a closure plug or flange to prevent any leakage when the connection is not in use. 6.4.5 Sample connections used only for vapour samples may be fitted with a single valve in accordance with [5], [8] and [13], and shall also be fitted with a closure plug or flange.

6.5 Cargo filters 6.5.1 The cargo liquid and vapour systems shall be capable of being fitted with filters to protect against damage by foreign objects. Such filters may be permanent or temporary, and the standards of filtration shall be appropriate to the risk of debris etc., entering the cargo system. Means shall be provided to indicate that filters are becoming blocked. Means shall be provided to isolate, depressurize and clean the filters safely. Guidance note: Blockage of filters can be determined by use of the pressure indicators in the cargo system. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7 Installation requirements 7.1 Design for expansion and contraction 7.1.1 Provision shall be made to protect the piping, piping system and components and cargo tanks from excessive stresses due to thermal movement and from movements of the tank and hull structure. The preferred method outside the cargo tanks is by means of offsets, bends or loops, but multi-layer bellows may be used if offsets, bends or loops are not practicable.

7.2 Precautions against low-temperature 7.2.1 Low temperature piping shall be thermally isolated from the adjacent hull structure, where necessary, to prevent the temperature of the hull from falling below the design temperature of the hull material. Where liquid piping is dismantled regularly, or where liquid leakage may be anticipated, such as at shore connections and at pump seals, protection for the hull beneath shall be provided. 7.2.2 Protection for the hull beneath shall be provided for ships intended to carry liquefied gases with boiling points lower than -15°C. The protecting arrangement shall consist of a liquid-tight insulation, e.g. a wooden

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 101

Part 5 Chapter 7 Section 5

6.4 Cargo sampling connections

— The coaming height shall be at least 150 mm. — Elevated drip trays shall measure at least 1.2 × 1.2 m and have a volume of at least 200 litres. Such trays shall be drained over the ship's side.

7.3 Water curtain 7.3.1 For cargo temperatures below -110°C, a water distribution system shall be fitted in way of the hull under the shore connections to provide a low-pressure water curtain for additional protection of the hull steel and the ship's side structure. This system is in addition to the requirements of Sec.11 [3.1.1] .4, and shall be operated when cargo transfer is in progress.

7.4 Bonding 7.4.1 Where tanks or cargo piping and piping equipment are separated from the ship's structure by thermal isolation, provision shall be made for electrically bonding both the piping and the tanks. All gasketed pipe joints and hose connections shall be electrically bonded. Except where bonding straps are used, it shall be demonstrated that the electrical resistance of each joint or connection is less than 1MΩ. Guidance note: The value of resistance 1MΩ may be achieved without the use of bonding straps where cargo piping systems and equipment are directly, or via their supports, either welded or bolted to the hull of the ship. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

8 Piping fabrication and joining details 8.1 General 8.1.1 The requirements of this section apply to piping inside and outside the cargo tanks. Relaxation from these requirements may be accepted by the Society for piping inside cargo tanks and open-ended piping. 8.1.2 In general the piping system shall be joined by welding with a minimum of flange connections. Gaskets shall be of a type designed to prevent blow-out. Guidance note: Gasket should prevent blow out by having a design like stainless spiral wound, recess flanges, protective stainless steel ring etc. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

8.2 Direct connections 8.2.1 The following direct connection of pipe lengths, without flanges, may be considered:

.1

Butt-welded joints with complete penetration at the root may be used in all applications. For design temperatures colder than -10°C, butt welds shall be either double welded or equivalent to a double welded butt joint. This may be accomplished by use of a backing ring, consumable insert or inert gas backup on the first pass. For design pressures in excess of 1 MPa and design temperatures of -10°C or colder, backing rings shall be removed.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 102

Part 5 Chapter 7 Section 5

deck or a free, elevated drip tray, or it shall be made from a steel grade corresponding to the requirements for secondary barriers. The insulation or special steel deck shall extend to the ship's side and shall have a width of at least 1.2 m. The deck area shall be bounded by coamings on all sides except on the deck corner side.

Slip-on welded joints with sleeves and related welding, having dimensions in accordance with recognized standards, shall only be used for instrument lines and open-ended lines with an external diameter of 50 mm or less and design temperatures not colder than -55°C, and:

.3

Screwed couplings complying with recognized standards shall only be used for accessory lines and instrumentation lines with external diameters of 25 mm or less.

8.3 Flanged connections 8.3.1 Flanges in flange connections shall be of the welded neck, slip-on or socket welded type. 8.3.2 Flanges shall comply with recognized standards for their type, manufacture and test. For all piping except open ended, the following restrictions apply:

.1 .2

for design temperatures colder than -55°C, only welded neck flanges shall be used, and for design temperatures colder than -10°C, slip-on flanges shall not be used in nominal sizes above 100 mm and socket welded flanges shall not be used in nominal sizes above 50 mm.

8.4 Expansion joints 8.4.1 Where bellows and expansion joints are provided in accordance with [7.1], the following requirements apply:

.1 .2

if necessary, bellows shall be protected against icing and slip joints shall not be used except within the cargo tanks.

8.5 Other connections 8.5.1 Piping connections other than those mentioned above, may be accepted upon consideration in each case.

9 Welding, post-weld heat treatment and non-destructive testing 9.1 General 9.1.1 Welding shall be carried out in accordance with Sec.6 [5].

9.2 Post-weld heat treatment 9.2.1 Post-weld heat treatment shall be required for all butt welds of pipes made with carbon, carbonmanganese and low alloy steels. The Society may waive the requirements for thermal stress relieving of pipes with wall thickness less than 10 mm in relation to the design temperature and pressure of the piping system concerned.

9.3 Non-destructive testing 9.3.1 In addition to normal controls before and during the welding, and to the visual inspection of the finished welds, as necessary for proving that the welding has been carried out correctly and according to the requirements of this paragraph, the following tests shall be required.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 103

Part 5 Chapter 7 Section 5

.2

100% radiographic or ultrasonic inspection of butt-welded joints for piping systems with design temperatures colder than -10°C, and with inside diameters of more than 75 mm, or wall thicknesses greater than 10 mm

.2

When such butt welded joints of piping sections are made by automatic welding procedures upon special approved by the Society, then a progressive reduction in the extent of radiographic or ultrasonic inspection can be agreed, but in no case to less than 10% of each joint. If defects are revealed, the extent of examination shall be increased to 100% and shall include inspection of previously accepted welds. This approval can only be granted if well-documented quality assurance procedures and records are available to enable the Society to assess the ability of the manufacturer to produce satisfactory welds consistently, and:

.3

For other butt-welded joints of pipes not covered by .1 and .2, spot radiographic or ultrasonic inspection or other non-destructive tests shall be carried out at the discretion of the Society depending upon service, position and materials. In general, at least 10% of butt-welded joints of pipes shall be subjected to radiographic or ultrasonic inspection.

9.3.2 The radiographs shall be assessed according to ISO 10675 and shall at least meet the criteria for level 2 on general areas and level 1 on critical areas as given in Pt.2 Ch.4 Sec.7 [5.1].

10 Installation requirements for cargo piping outside the cargo area 10.1 Bow and stern loading arrangements 10.1.1 The following provisions shall apply to cargo piping and related piping equipment located outside the cargo area:

.1

Cargo piping and related piping equipment outside the cargo area shall have only welded connections. The piping outside the cargo area shall run on the weather decks and shall be at least 0.8 m inboard, except for athwartships shore connection piping. Such piping shall be clearly identified and fitted with a shutoff valve at its connection to the cargo piping system within the cargo area. At this location it shall also be capable of being separated, by means of a removable spool piece and blank flanges, when not in use, and:

.2

The piping shall be full penetration butt-welded and subjected to full radiographic or ultrasonic inspection, regardless of pipe diameter and design temperature. Flange connections in the piping shall only be permitted within the cargo area and at the shore connection.

.3

Arrangements shall be made to allow such piping to be purged and gas-freed after use. When not in use, the spool pieces shall be removed and the pipe ends be blank-flanged. The vent pipes connected with the purge shall be located in the cargo area.

10.2 Turret compartment transfer systems 10.2.1 The following provisions shall apply to liquid and vapour cargo piping where it is run outside the cargo area.

.1

cargo piping and related piping equipment outside the cargo area shall have only welded connections, and

.2

the piping shall be full penetration butt welded, and subjected to full radiographic or ultrasonic inspection, regardless of pipe diameter and design temperature. Flange connections in the piping shall only be permitted within the cargo area and at connections to cargo hoses and the turret connection.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 104

Part 5 Chapter 7 Section 5

.1

10.3.1 Gas fuel piping, as far as practicable, shall have welded joints. Those parts of the gas fuel piping that are not enclosed in a ventilated pipe or duct according to Sec.16 [4.3], and are on the weather decks outside the cargo area, shall have full penetration butt-welded joints and shall be subjected to full radiographic or ultrasonic inspection.

11 Piping system component requirements 11.1 General 11.1.1 Piping scantlings: piping systems shall be designed in accordance with this chapter. 11.1.2 The following criteria shall be used for determining pipe wall thickness. The wall thickness of pipes shall not be less than, in mm:

where to is the theoretical thickness in mm, determined by the following formula

where:

P D K e

= design pressure in MPa referred to in [4]

b

= allowance for bending in mm. The value of b shall be chosen so that the calculated stress in the bend, due to internal pressure only, does not exceed the allowable stress. Where such justification is not given, b shall be:

= outside diameter in mm = allowable stress in N/mm² referred to in [11.2] = efficiency factor equal to 1.0 for seamless pipes and for longitudinally or spirally welded pipes, delivered by approved manufacturers of welded pipes, that are considered equivalent to seamless pipes when non-destructive testing on welds is carried out in accordance with recognized standards. In other cases, an efficiency factor of less than 1.0, in accordance with recognized standards, may be required, depending on the manufacturing process

where:

r = mean radius of the bend in mm c = corrosion allowance in mm. If corrosion or erosion is expected, the wall thickness of the piping shall be increased over that required by other design requirements. This allowance shall be consistent with the expected life of the piping, and

a = negative manufacturing tolerance for thickness in %.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 105

Part 5 Chapter 7 Section 5

10.3 Gas fuel piping

11.1.4 Where necessary for mechanical strength to prevent damage, collapse, excessive sag or buckling of pipes due to superimposed loads, the wall thickness shall be increased over that required by [11.1.2] or, if this is impracticable or would cause excessive local stresses, these loads may be reduced, protected against or eliminated by other design methods. Such superimposed loads may be due to: supporting structures, ship deflections, liquid pressure surge during transfer operations, the weight of suspended valves, reaction to loading arm connections, or otherwise.

11.2 Allowable stress 11.2.1 For pipes, the allowable stress to be considered in the formula for t in [11.1.2] is the lower of the following values:

where:

Rm ReH

2

= specified minimum tensile strength at room temperature in N/mm as given in Sec.1, and 2

= specified minimum yield stress at room temperature in N/mm as given in Sec.1. If the stress-strain curve does not show a defined yield stress, the 0.2% proof stress applies.

The values of A and B shall not be taken less than A = 2.7 and B = 1.8. 11.2.2 For pipes made of materials other than steel, the allowable stress shall be considered by the Society.

11.3 High pressure gas fuel outer pipes or ducting scantlings 11.3.1 In fuel gas piping systems of design pressure greater than the critical pressure, the tangential membrane stress of a straight section of pipe or ducting shall not exceed the tensile strength divided by 1.5, i.e. Rm/1.5 when subjected to the design pressure specified in [4]. The pressure ratings of all other piping components shall reflect the same level of strength as straight pipes.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 106

Part 5 Chapter 7 Section 5

11.1.3 The minimum thickness shall be in accordance with Pt.4 Ch.6 Sec.9 Table 4 for austenitic stainless steel, and Pt.4 Ch.6 Sec.9 Table 3 for C-Mn steel.

For high-pressure piping the design pressure of the ducting should be taken as the highest of the following: —

the maximum built up pressure: static pressure in way of the rupture resulting from the gas flowing in the annular space

—

local instantaneous peak pressure in way of the rupture p*: this pressure shall be taken as the critical pressure and is given by the following expression:

p

=

p0 =

maximum working pressure of the inner pipe

k

=

Cp/Cv constant pressure specific heat divided by the constant volume specific heat

k

=

1.31 for CH4

The tangential membrane stress of a straight pipe should not exceed the tensile strength divided by 1.5 (Rm/1.5) when subjected to the above pressure. The pressure ratings of all other piping components shall reflect the same level of strength as straight pipes. As an alternative to using the peak pressure from the above formula, the peak pressure found from representative tests can be used. In this case, test reports shall be submitted. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

11.4 Stress analysis 11.4.1 When the design temperature is -110°C or lower, a complete stress analysis, taking into account all the stresses due to weight of pipes, including acceleration loads if significant, internal pressure, thermal contraction and loads induced by hog and sag of the ship for each branch of the piping system shall be submitted. For temperatures above –110°C, a stress analysis may be required by the Society in relation to such matters as the design or stiffness of the piping system and the choice of materials. In any case, consideration shall be given to thermal stresses even though calculations are not submitted. The analysis may be carried out according to Pt.4 Ch.6 or to a recognised code of practice accepted by the Society.

11.5 Flanges, valves and fittings 11.5.1 Flanges, valves and other fittings shall comply with recognized standards, taking into account the material selected and the design pressure defined in [4]. For bellows expansion joints used in vapour service, a lower minimum design pressure may be accepted. 11.5.2 For flanges not complying with a recognized standard, the dimensions of flanges and related bolts shall be to the satisfaction of the Society. 11.5.3 All emergency shutdown valves shall be of the fire closed type, see [13.1.1] and Sec.18 [2.2]. Guidance note: Fire closed means valve shall be fail-closed type (i.e. closed on loss of actuating power) and made of materials having melting temperature above 925°C. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

11.5.4 The design and installation of expansion bellows shall be in accordance with recognized standards and be fitted with means to prevent damage due to over-extension or compression. Guidance note: Means to prevent damage due to over-extension and compression i.e. anchoring supports are to be fitted. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 107

Part 5 Chapter 7 Section 5

Guidance note:

11.6.1 Liquid and vapour hoses used for cargo transfer shall be compatible with the cargo and suitable for the cargo temperature. 11.6.2 Hoses subject to tank pressure or the discharge pressure of pumps or vapour compressors, shall be designed for a bursting pressure not less than five times the maximum pressure the hose will be subjected to during cargo transfer. 11.6.3 Each new type of cargo hose, complete with end-fittings, shall be prototype-tested at a normal ambient temperature, with 200 pressure cycles from zero to at least twice the specified maximum working pressure. After this cycle pressure test has been carried out, the prototype test shall demonstrate a bursting pressure of at least five (5) times its specified maximum working pressure at the upper and lower extreme service temperature. Hoses used for prototype testing shall not be used for cargo service. Thereafter, before being placed in service, each new length of cargo hose produced shall be hydrostatically tested at ambient temperature to a pressure not less than 1.5 times its specified maximum working pressure, but not more than two fifths of its bursting pressure. The hose shall be stencilled or otherwise marked with the date of testing, its specified maximum working pressure and, if used in services other than ambient temperature services, its maximum and minimum service temperature, as applicable. The specified maximum working pressure shall not be less than 1 MPa.

12 Materials 12.1 General 12.1.1 The choice and testing of materials used in piping systems shall comply with the requirements of Sec.6, taking into account the minimum design temperature. However, some relaxation may be permitted in the quality of material of open-ended vent piping, provided that the temperature of the cargo at the pressure relief valve setting is not lower than -55°C, and provided that no liquid discharge to the vent piping can occur. Similar relaxations may be permitted under the same temperature conditions to open-ended piping inside cargo tanks, excluding discharge piping and all piping inside membrane and semi-membrane tanks. 12.1.2 Materials having a melting point (solidus temperature) below 925°C shall not be used for piping outside the cargo tanks except for short lengths of pipes attached to the cargo tanks, in which case fireresisting insulation shall be provided.

12.2 Cargo piping insulation system 12.2.1 Cargo piping systems shall be provided with a thermal insulation system as required to minimize heat leak into the cargo during transfer operations and to protect personnel from direct contact with cold surfaces. 12.2.2 Where applicable, due to location or environmental conditions, insulation materials shall have suitable properties of resistance to fire and flame spread and shall be adequately protected against penetration of water vapour and mechanical damage. 12.2.3 Where the cargo piping system is of a material susceptible to stress corrosion cracking in the presence of a salt-laden atmosphere, adequate measures to avoid this occurring shall be taken by considering material selection, protection of exposure to salty water and/or readiness for inspection.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 108

Part 5 Chapter 7 Section 5

11.6 Ships' cargo hoses

13.1 Valves 13.1.1 Prototype testing Each type of valve intended to be used at a working temperature below -55°C shall be subject to design assessment and the following type tests witnessed by the Society’s representative:

.1

Each size and type of valve shall be subjected to seat tightness testing over the full range of operating pressures for bi-directional flow and cryogenic temperatures, at intervals, up to the rated design pressure of the valve. Allowable leakage rates shall be to the requirements of the Society. During the testing, satisfactory operation of the valve shall be verified.

.2 .3 .4

The flow or capacity shall be certified to a recognized standard for each size and type of valve.

.5

For valves other than safety valves, a seat and stem leakage test at a pressure equal to 1.1 times the design pressure.

Pressurized components shall be pressure tested to at least 1.5 times the design pressure. For emergency shutdown valves, with materials having melting temperatures (solidus temperature) lower than 925°C, the type testing shall include a fire test to a standard acceptable to the Society.

13.1.2 Production testing All valves shall be tested at the plant of manufacturer in the presence of the Society’s representative. Testing shall include hydrostatic test of the valve body at a pressure equal to 1.5 times the design pressure for all valves as given in [13.1.1] .3, seat and stem leakage test at a pressure equal to 1.1 times the design pressure for valves other than safety valves. In addition, cryogenic testing consisting of valve operation and leakage verification for a minimum of 10% of each type and size of valve for valves other than safety valves intended to be used at a working temperature below -55°C. The set pressure of safety valves shall be tested at ambient temperature. For valves used for isolation of instrumentation in piping not greater than 25 mm, unit production testing need not be witnessed by the surveyor. Records of testing shall be available for review. See IACS GC 12. As an alternative to the above, if so requested by the relevant manufacturer, the certification of a valve may be issued subject to all the following conditions: — The valve has been approved as required by [13.1.1] for valves intended to be used at a working temperature below -55°C. — The manufacturer has a recognized quality system that has been assessed and certified by the Society subject to periodic audits. — The quality control plan contains a provision to subject each valve to a hydrostatic test of the valve body at a pressure equal to 1.5 times the design pressure for all valves and seat and stem leakage test at a pressure equal to 1.1 times the design pressure for valves other than safety valves. The set pressure of safety valves shall be tested at ambient temperature. The manufacturer shall maintain records of such tests. — Cryogenic testing consisting of valve operation and leakage verification for a minimum of 10% of each type and size of valve for valves other than safety valves intended to be used at a working temperature below -55°C. Guidance note: Cargo tank pressure relief valves are covered separately in Sec.8 [2]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 109

Part 5 Chapter 7 Section 5

13 Testing and construction

13.2.1 The following prototype tests shall be performed on each type of expansion bellows intended for use on cargo piping outside the cargo tank and where required by the Society, on those installed within the cargo tanks:

.1

Elements of the bellows, not pre-compressed, shall be pressure tested at not less than five times the design pressure without bursting. The duration of the test shall not be less than five minutes.

.2

A pressure test shall be performed on a type expansion joint, complete with all the accessories such as flanges, stays and articulations, at the minimum design temperature and twice the design pressure at the extreme displacement conditions recommended by the manufacturer without permanent deformation.

.3

A cyclic test (thermal movements) shall be performed on a complete expansion joint, which shall withstand at least as many cycles under the conditions of pressure, temperature, axial movement, rotational movement and transverse movement as it will encounter in actual service. Testing at ambient temperature is permitted when this testing is at least as severe as testing at the service temperature, and:

.4

A cyclic fatigue test (ship deformation) shall be performed on a complete expansion joint, without internal pressure, by simulating the bellows movement corresponding to a compensated pipe length, for at least 2 000 000 cycles at a frequency not higher than 5 Hz. This test is only required when, due to the piping arrangement, ship deformation loads are actually experienced.

13.3 Piping system testing requirements 13.3.1 The requirements of this section shall apply to piping inside and outside the cargo tanks. 13.3.2 After assembly, all cargo and process piping shall be subjected to a strength test with a suitable fluid. The test pressure shall be at least 1.5 times the design pressure (1.25 times the design pressure where the test fluid is compressible) for liquid lines and 1.5 times the maximum system working pressure (1.25 times the maximum system working pressure where the test fluid is compressible) for vapour lines. When piping systems or parts of systems are completely manufactured and equipped with all fittings, the test may be conducted prior to installation on board the ship. Joints welded on board shall be tested to at least 1.5 times the design pressure. Guidance note: If testing is done with a compressible fluid, safety considerations must be taken. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

13.3.3 After assembly on board, each cargo and process piping system shall be subjected to a leak test using air, or other suitable medium to a pressure depending on the leak detection method applied. 13.3.4 In double wall gas-fuel piping systems the outer pipe or duct shall also be pressure tested to show that it can withstand the expected maximum pressure at gas pipe rupture. 13.3.5 All piping systems, including valves, fittings and associated equipment for handling cargo or vapours, shall be tested under normal operating conditions not later than at the first loading operation, in accordance with approved programme.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 110

Part 5 Chapter 7 Section 5

13.2 Expansion bellows

The closing characteristics of emergency shutdown valves used in liquid cargo piping systems shall be tested to demonstrate compliance with Sec.18 [2.2.3]. The ESD valves with actuators shall be function tested when the valve is subjected to full working pressure. This testing may be carried out on board after installation.

13.5 Pumps 13.5.1 Prototype testing Each size and type of pump shall be approved through design assessment and prototype testing. Prototype testing shall be witnessed in the presence of the Society’s representative. In lieu of prototype testing, satisfactory in-service experience, of an existing pump submitted by the manufacturer may be considered. Prototype testing shall include hydrostatic test of the pump body equal to 1.5 times the design pressure and a capacity test. For submerged electric motor driven pumps, the capacity test shall be carried out with the design medium or with a medium below the minimum working temperature. For shaft driven deep well pumps, the capacity test may be carried out with water. In addition, for shaft driven deep well pumps, a spin test to demonstrate satisfactory operation of bearing clearances, wear rings and sealing arrangements shall be carried out at the minimum design temperature. The full length of shafting is not required for the spin test, but shall be of sufficient length to include at least one bearing and sealing arrangements. After completion of tests, the pump shall be opened out for examination. 13.5.2 Production testing All pumps shall be tested at the plant of manufacturer in the presence of the Society’s representative. Testing shall include hydrostatic test of the pump body equal to 1.5 times the design pressure and a capacity test. For submerged electric motor driven pumps, the capacity test shall be carried out with the design medium or with a medium below the minimum working temperature. For shaft driven deep well pumps, the capacity test may be carried out with water. As an alternative to the above, if so requested by the relevant manufacturer, the certification of a pump may be issued subject to all the following conditions: — The pump has been approved as required by [13.5.1]. — The manufacturer has a recognised quality system that has been assessed and certified by the Society subject to periodic audits. — The quality control plan contains a provision to subject each pump to a hydrostatic test of the pump body equal to 1.5 times the design pressure and a capacity test. The manufacturer shall maintain records of such tests.

13.6 Cargo process pressure vessels 13.6.1 Cargo process pressure vessels shall meet the requirements for scantlings, manufacture, workmanship, inspection and non-destructive testing for class I pressure vessels as given in Pt.4 Ch.7. 13.6.2 Materials in cargo process pressure vessels, welding procedure tests and production weld tests shall be in accordance with Sec.6, while pressure testing and nominal design stress shall be in accordance Sec.22 [7.1.1] as type C tank.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 111

Part 5 Chapter 7 Section 5

13.4 Emergency shutdown valves

1 General 1.1 Definitions 1.1.1 Where reference is made to A, B, D, E, AH, DH, EH and FH hull structural steels, these steel grades are hull structural steels according to Pt.2 Ch.2 Sec.2 (H means high strength steels of corresponding grade). 1.1.2 A piece is the rolled product from a single slab or billet or from a single ingot, if this is rolled directly into plates, strips, sections or bars. 1.1.3 A batch is the number of items or pieces to be accepted or rejected together, on the basis of the tests to be carried out on a sampling basis. The size of a batch is given in rules Pt.2 Ch.4. 1.1.4 Normalizing rolling (NR) and controlled rolling (CR) is a rolling procedure in which the final rolling temperature is controlled within a certain range above the Ar3 temperature so that the austenite completely re-crystallises. After the final pass, air cooling produces a fine grained ferrite-pearlite microstructure comparable to that obtained after normalising heat treatment. 1.1.5 Thermo-mechanical rolling (TM) and thermo-mechanical controlled processing (TMCP) is a rolling procedure in which both the rolling temperatures and reductions and, when used, accelerated cooling conditions are controlled. Generally, a high proportion of the rolling reduction is carried out close to the Ar3 temperature and may involve the rolling in the austenite-ferrite dual phase temperature region. After the final pass, either air cooling or accelerated cooling, excluding quenching, is used. Final rolling in the same temperature range as used for NR followed by accelerated cooling is considered to be a TM procedure. Unlike NR the properties conferred by TM cannot be reproduced by subsequent normalising heat treatment. 1.1.6 Accelerated cooling (AcC) is a process that aims to improve mechanical properties by controlled cooling with rates higher than air cooling, immediately after the final TM operation. Direct quenching is excluded from accelerated cooling. The material properties conferred by TM and AcC cannot be reproduced by subsequent normalizing or other heat treatment.

2 Scope 2.1 General requirements 2.1.1 This section gives the requirements for metallic and non-metallic materials used in the construction of the cargo system. This includes requirements for joining processes, production process, personnel qualification, NDT and inspection and testing including production testing. The requirements for rolled materials, forgings and castings are given in [4] and Table 1 to Table 5. The requirements for weldments are given in [5], and the guidance for non-metallic materials is given in App.A. Material manufacturers shall be approved by the Society according to the requirements of Pt.2, ensuring that a quality assurance/quality control program is implemented. 2.1.2 The manufacture, testing, inspection and documentation shall be in accordance with Pt.2. 2.1.3 Where post-weld heat treatment is specified or required, the properties of the base material shall be determined in the heat-treated condition, in accordance with Pt.2 and the applicable table of this section. The weld properties shall be determined in the heat treated condition in accordance with Pt.2 and in accordance

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 112

Part 5 Chapter 7 Section 6

SECTION 6 MATERIALS OF CONSTRUCTION, QUALITY CONTROL AND MARKING

2.1.4 Detailed requirements for chemical composition, mechanical properties, notch toughness etc. for plates, sections, pipes, forgings, castings and weldments used in the construction of cargo tanks, cargo process pressure vessels, cargo piping, secondary barriers and contiguous hull structures associated with the transportation of the products are found in Pt.2. 2.1.5 Steels for low temperature application shall follow the requirements of Pt.2 Ch.2 in addition to the requirements given herein. 2.1.6 Fabrication (welding, NDT, etc.) shall follow the requirements of Pt.2 Ch.4 in addition to the requirements given herein. 2.1.7 Materials other than those covered by Pt.2 and referred to in this section may be accepted subject to approval in each separate case. 2.1.8 For certain cargoes as specified in Sec.19, special requirements for materials apply. 2.1.9 Thermal insulation materials shall be in compliance with the requirements of Sec.4 [2.8].

3 General test requirements and specifications 3.1 Tensile tests 3.1.1 Tensile testing shall be carried out in accordance with Pt.2 Ch.1. 3.1.2 Tensile strength, yield stress and elongation shall meet the requirements of Pt.2 Ch.2, unless otherwise approved by the Society.

3.2 Toughness tests 3.2.1 Acceptance tests for metallic materials shall include Charpy V-notch toughness tests, unless otherwise approved by the Society. The largest size Charpy V-notch specimens possible for the material thickness shall be machined with the centreline of the specimens (C/L specimen) located as near as practicable to a line midway between the surface and the centre of the plate thickness, and with the notch direction perpendicular to the surface as shown in Figure 1 and Figure 2. The distance from the surface of the material to the specimen shall be approximately 1 mm to 2 mm. The specified Charpy V-notch requirements are minimum average energy values for three full size (10 mm × 10 mm) specimens and minimum single energy values for individual specimens. Dimensions and tolerances of Charpy V-notch specimens shall be in accordance with Pt.2 Ch.1. The testing and requirements for specimen width smaller than 5 mm shall be in accordance with a recognized standard. Minimum average values for subsized specimens shall be:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 113

Part 5 Chapter 7 Section 6

with [5]. However, in cases where a post-weld heat treatment is applied the test requirements may be modified at the discretion of the Society.

Minimum average energy of three specimens

10 x 10

KV

10 x 7.5

5/6 KV

10 x 5

2/3 KV

where:

KV

= the energy values (J) specified in Table 1 to Table 4.

Only one individual value may be below the specified average value, provided it is not less than 70% of that value. 3.2.2 For base metal, the test specimen location and notch location is indicated in Figure 1.

Figure 1 Orientation of base metal test specimen 3.2.3 For a weld test specimen, test specimen location and notch locations are indicated in Figure 2. For double-V butt welds, the specimens shall be machined from the side containing the last weld run.

Figure 2 Orientation of weld test specimen

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 114

Part 5 Chapter 7 Section 6

Charpy Vnotch specimen size (mm)

.1 .2 .3 .4 .5

centerline of the weld fusion line in heat-affected zone (HAZ), 1 mm from the fusion line in HAZ, 3 mm from the fusion line in HAZ, 5 mm from the fusion line

3.3 Bend test 3.3.1 The bend test may be omitted as a base material acceptance test, but is required for weld tests. Where a bend test is performed, this shall be done in accordance with Pt.2 Ch.1. 3.3.2 The bend tests for the welds shall be transverse to the welding direction, and may be face, root or side bend test at the discretion of the Society. However, longitudinal bend tests may be required in lieu of transverse bend tests in cases where the base material and weld metal have different strength levels. For bend tests of welds, see Pt.2 Ch.4.

3.4 Section observation and other testing 3.4.1 Macrosection, microsection observations and hardness tests may also be required by the Society, and they shall be carried out in accordance with Pt.2 Ch.1, where required.

4 Requirements for metallic materials 4.1 General requirements for metallic materials 4.1.1 Metallic materials shall in general follow the requirements of Pt.2 Ch.2 in addition to the requirements given herein. 4.1.2 The requirements for materials of construction are shown in the tables as follows: .1

Table 1

plates, pipes (seamless and welded), sections and forgings for cargo tanks and process pressure vessels for design temperatures not lower than 0°C

.2

Table 2

plates, sections and forgings for cargo tanks, secondary barriers and process pressure vessels for design temperatures below 0°C and down to -55°C

.3

Table 3

plates, sections and forgings for cargo tanks, secondary barriers and process pressure vessels for design temperatures below -55°C and down to -165°C

.4

Table 4

pipes (seamless and welded), forgings and castings for cargo and process piping for design temperatures below 0°C and down to -165°C

.5

Table 5

plates and sections for hull structures required by Sec.4 [5.1.1].2 and Sec.4 [5.1.1] .3

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 115

Part 5 Chapter 7 Section 6

The specimens shall be taken at each of the following notch locations as shown in Figure 2:

1) 2)

Part 5 Chapter 7 Section 6

Table 1 Plates, pipes (seamless and welded) , sections and forgings for cargo tanks and process pressure vessels for design temperatures not lower than 0°C CHEMICAL COMPOSITION AND HEAT TREATMENT carbon-manganese steel fully killed fine grain steel small additions of alloying elements by agreement with the Society composition limits shall follow the relevant requirements of Pt.2. normalized, or quenched and tempered

4)

TENSILE AND TOUGHNESS (IMPACT) TEST REQUIREMENTS Sampling frequency plates

each piece to be tested

sections and forgings

each batch to be tested Mechanical properties specified minimum yield stress not to exceed 410 N/ 2)5) mm

tensile properties

Toughness (Charpy V-notch test) plates

transverse test pieces. Minimum average energy value (KV) 27J

sections and forgings

longitudinal test pieces. Minimum average energy (KV) 41J Thickness t in mm

test temperature

Test temperature in °C

t ≤ 20 20 < t ≤ 40

0 3)

-20

1)

For seamless pipes and fittings normal practice applies. The use of longitudinally and spirally welded pipes shall be specially approved by the Society.

2)

Charpy V-notch impact tests are not required for pipes.

3)

This table is generally applicable for material thicknesses up to 40 mm. Proposals for greater thicknesses shall be approved by the Society.

4)

Steels with delivery conditions NR (CR) or TM may be used as an alternative.

5)

Materials with specified minimum yield stress exceeding 410 N/mm may be approved by the Society. For these materials, particular attention shall be given to the hardness of the welds and heat affected zones.

2

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 116

CHEMICAL COMPOSITION AND HEAT TREATMENT carbon-manganese steel fully killed, aluminium treated fine grain steel chemical composition (ladle analysis) C 0.16% max

3)

Mn

Si

S

P

0.7-1.60%

0.1-0.50%

0.025% max

0.025% max

Optional additions: alloys and grain refining elements may be generally in accordance with the following: Ni

Cr

Mo

Cu

Nb

V

0.8% max

0.25% max

0.08% max

0.35% max

0.05% max

0.1% max

Al content total 0.02% min (Acid soluble 0.015% min) normalized, or quenched and tempered

4)

TENSILE AND TOUGHNESS (IMPACT) TEST REQUIREMENTS Sampling frequency plates

each piece to be tested

sections and forgings

each batch to be tested Mechanical properties

tensile properties

specified minimum yield stress not to exceed 2)5) 410 N/mm Toughness (Charpy V-notch test)

plates

transverse test pieces. minimum average energy value (KV) 27J

sections and forgings

longitudinal test pieces. minimum average energy (KV) 41J

test temperature

5°C below the design temperature or -20°C, whichever is lower

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 117

Part 5 Chapter 7 Section 6

1)

Table 2 Plates, sections and forgings for cargo tanks, secondary barriers and process pressure 2) vessels for design temperatures below 0°C and down to -55°C maximum thickness 25 mm

The Charpy V-notch and chemistry requirements for forgings for low temperature service are given in Pt.2 Ch.2.

2)

For material thickness of more than 25 mm, Charpy V-notch tests shall be conducted as follows:

Material thickness (mm)

Test temperature (°C)

25 < t ≤ 30

10°C below design temperature or -20°C, whichever is lower

30 < t ≤ 35

15°C below design temperature or -20°C, whichever is lower

35 < t ≤ 40

20°C below design temperature

t > 40

temperature approved by the Society

The impact energy value shall be in accordance with the table for the applicable type of test specimen. Materials for tanks and parts of tanks which are completely thermally stress relieved after welding may be tested at a temperature 5°C below design temperature or -20°C, whichever is lower. For thermally stress relieved reinforcements and other fittings, the test temperature shall be the same as that required for the adjacent tank-shell thickness. 3)

By special agreement with the Society, the carbon content may be increased to 0.18 % maximum, provided the design temperature is not lower than -40°C.

4)

Steels with delivery conditions NR (CR) or TM may be used as an alternative.

5)

Materials with specified minimum yield stress exceeding 410 N/mm may be approved by the Society. For these materials, particular attention shall be given to the hardness of the welded and heat affected zones.

2

Guidance note: For materials exceeding 25 mm in thickness for which the test temperature is -60°C or lower, the application of specially treated steels or steels in accordance with Table 3 may be necessary. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 118

Part 5 Chapter 7 Section 6

1)

3)4)

Minimum design temperature in °C

Chemical composition see note 5 and heat treatment

Impact test temperature in °C

-60

1.5% nickel steel – normalized or normalized and tempered or 6) quenched and tempered or TMCP

-65

-65

2.25% nickel steel – normalized or normalized and 6) 7) tempered or quenched and tempered or TMCP

-70

-90

3.5% nickel steel – normalized or normalized and tempered or 6) 7) quenched and tempered or TMCP

-95

-105

5% nickel steel – normalized or normalized and tempered or quenched 6) 7) 8) and tempered

-110

-165

9% nickel steel – double normalized and tempered or quenched and 6) tempered

-196

-165

austenitic steels, such as types 304, 304L, 316, 316L, 321 and 347 9) solution treated

-196

-165

aluminium alloys; such as type 5083 annealed

not required

-165

austenitic Fe-Ni alloy (36% nickel). Heat treatment as agreed

not required

TENSILE AND TOUGHNESS (IMPACT) TEST REQUIREMENTS Sampling frequency plates

each piece to be tested

sections and forgings

each batch to be tested Toughness (Charpy V-notch test)

plates

transverse test pieces. minimum average energy value (KV) 27J

sections and forgings

longitudinal test pieces. minimum average energy (KV) 41J

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 119

Part 5 Chapter 7 Section 6

1)

Table 3 Plates, sections and forgings for cargo tanks, secondary barriers and process pressure 2) vessels for design temperatures below -55°C and down to -165°C maximum thickness 25 mm

Chemical composition see note 5 and heat treatment

Impact test temperature in °C

1)

The impact test required for forgings used in critical applications shall be subject to special consideration by the Society.

2)

The requirements for design temperatures below -165°C shall be specially agreed with the Society.

3)

For materials 1.5% Ni, 2.25% Ni, 3.5% Ni and 5% Ni, with thicknesses greater than 25 mm, the impact tests shall be conducted as follows:

Material thickness (mm)

Test temperature (°C)

25 < t ≤ 30

10°C below design temperature

30 < t ≤ 35

15°C below design temperature

35 < t ≤ 40

20°C below design temperature

The energy value shall be in accordance with the table for the applicable type of test specimen. For material thickness of more than 40 mm, the Charpy V-notch requirements (e.g. test temperature, test specimen location and acceptance criteria) shall be specially considered. 4)

For 9% Ni steels, austenitic stainless steels and aluminium alloys, thickness greater than 25 mm may be used. However, for thickness more than 40 mm, see last paragraph of note 3.

5)

The chemical composition limits shall be in accordance with Pt.2 Ch.2.

6)

Nickel steels with delivery condition TM shall be specially approved by the Society.

7)

A lower minimum design temperature for quenched and tempered steels may be specially agreed with the Society.

8)

A specially heat treated 5% nickel steel, for example triple heat treated 5% nickel steel, may be used down to -165°C, provided that the impact tests are carried out at -196°C.

9)

The impact test may be omitted, subject to agreement with the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 120

Part 5 Chapter 7 Section 6

Minimum design temperature in °C

2)

2)

Impact test Minimum design temperature in °C

Chemical composition

5)

and heat treatment

Test temp. in °C

Minimum average energy (KV) in J

-55

carbon-manganese steel. Fully killed fine grain. Normalized or 6) as agreed

-65 -90

4)

27

2.25% nickel steel. Normalized, normalized and tempered or 6) quenched and tempered

-70

34

3.5% nickel steel. Normalized, normalized and tempered or 6) quenched and tempered

-95

34

9% nickel steel . Double normalized and tempered or quenched and tempered

-196

41

austenitic steels, such as types 304. 304L, 316, 316L, 321 and 8) 347. Solution treated

-196

41

7)

-165

aluminium alloys; such as type 5083 annealed

not required

TENSILE AND TOUGHNESS (IMPACT) TEST REQUIREMENTS sampling frequency each batch to be tested toughness (Charpy V-notch test) impact test: longitudinal test pieces Notes 1)

The use of longitudinally or spirally welded pipes shall be specially approved by the Society.

2)

The requirements for forgings and castings for low temperature service are given in Pt.2 Ch.2.

3)

The requirements for design temperatures below -165°C shall be specially agreed with the Society.

4)

The test temperature shall be 5°C below the design temperature or -20°C, whichever is lower.

5)

The composition limits shall be in accordance with Pt.2 Ch.2, steels for low temperature service.

6)

A lower design temperature may be specially agreed with the Society for quenched and tempered materials.

7)

This grade is not suitable for castings.

8)

Impact tests may be omitted, subject to agreement with the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 121

Part 5 Chapter 7 Section 6

1)

Table 4 Pipes (seamless and welded) , forgings and castings for cargo and process piping 3) for design temperatures below 0°C and down to -165°C maximum thickness 25 mm

Steel significant temperature in °C 0 and above 3) and above

2)

Maximum thickness (mm) for steel grades in accordance with Pt.2 Ch.2 Sec.1 VL A

VL B

VL D

VL E

-5

Down to -5

VL AH

1)

VL DH

1)

VL EH

1)

VL FH

Normal practice 15

25

30

50

25

45

50

50

Down to -10

x

20

25

50

20

40

50

50

Down to -20

x

x

20

50

x

30

50

50

Down to -30

x

x

x

40

x

20

40

50

Below -30

1)

In accordance with Table 2 except that the thickness limitation given in Table 2 and in footnote 2 of that table does not apply.

x= steel grade not allowed. 1)

H means high strength steel.

2)

for the purpose of Sec.4 [5.1.1] .3.

3)

for the purpose of Sec.4 [5.1.1] .2.

5 Welding of metallic materials and non-destructive testing 5.1 General 5.1.1 Fabrication (welding, NDT, etc.) shall in general follow the requirements of Pt.2 Ch.4 in addition to the requirements given herein. 5.1.2 This section shall apply to primary and secondary barriers only, including the inner hull where this forms the secondary barrier. Acceptance testing is specified for carbon, carbon-manganese, nickel alloy and stainless steels, but these tests may be adapted for other materials. At the discretion of the Society, impact testing of stainless steel and aluminium alloy weldments may be omitted and other tests may be specially required for any material.

5.2 Welding consumables 5.2.1 Consumables intended for welding of cargo tanks shall be type approved by the Society, see [5.1.1].

5.3 Welding procedure tests for cargo tanks and process pressure vessels 5.3.1 For all butt welds and essential fillet welds of cargo tanks and process pressure vessels, approved welding procedure specifications (WPS) qualified by welding procedure qualification test (WPQT) is required, see Pt.2 Ch.4. The test assemblies shall be representative for:

.1 .2 .3

each type of base material each type of consumable and welding process, and each welding position.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 122

Part 5 Chapter 7 Section 6

Table 5 Plates and sections for hull structures required by Sec.4 [5.1.1].2 and Sec.4 [5.1.1].3

5.3.3 The following welding procedure tests for cargo tanks and process pressure vessels shall be carried out in accordance with [3], with specimens made from each test assembly:

.1 .2 .3

cross-weld tensile tests

.4

one set of three Charpy V-notch impact tests, generally at each of the following locations, as shown in Table 2:

longitudinal all-weld testing in accordance with Pt.2 Ch.4, where required by the Society transverse bend tests, which may be face, root or side bends. However, longitudinal bend tests may be required in lieu of transverse bend tests in cases where the base material and weld metal have different strength levels

.1 .2 .3 .4 .5 .5

centerline of the weld fusion line 1 mm from the fusion line 3 mm from the fusion line 5 mm from the fusion line, and

macro section, micro section and hardness survey may also be required by the Society.

5.3.4 Each test shall satisfy the following requirements:

.1

Tensile tests: cross-weld tensile strength shall not be less than the specified minimum tensile strength for the appropriate parent materials. The Society may also require that the transverse weld tensile strength is not to be less than the specified minimum tensile strength (SMTS) for the weld metal, in cases where the weld metal has a lower SMTS than that of the parent material. For aluminium alloys, reference shall be made to Sec.4 [4.3.2].3 with regard to the requirements for weld metal strength of under-matched welds (where the weld metal has a lower tensile strength than the parent metal). In every case, the position of fracture shall be recorded for information

.2

Bend tests: no fracture is acceptable after a 180° bend over a former of a diameter maximum four times the thickness of the test pieces, unless stricter requirements are specially required by or agreed with the Society, and:

.3

Charpy V-notch impact tests: Charpy V-notch tests shall be conducted at the temperature prescribed for the base material being joined. The results of weld metal impact tests, minimum average energy (KV), shall be no less than 27 J. The weld metal requirements for subsize specimens and single energy values shall be in accordance with [3.2]. The results of fusion line and heat-affected zone impact tests shall show a minimum average energy (KV) in accordance with the transverse or longitudinal requirements of the base material, whichever is applicable, and for subsize specimens, the minimum average energy (KV) shall be in accordance with [3.2]. If the material thickness does not permit machining of either full-size or standard subsize specimens, the testing procedure and acceptance standards shall be approved by the Society.

5.3.5 Procedure tests for fillet welding shall be in accordance with recognized standards. In such cases, consumables shall be so selected that exhibit satisfactory impact properties.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 123

Part 5 Chapter 7 Section 6

5.3.2 For butt welds in plates, the test assemblies shall be so prepared that the rolling direction is parallel to the direction of welding. The range of thickness qualified by each welding procedure test shall be in accordance with Pt.2 Ch.4. Radiographic or ultrasonic testing may be performed at the option of the fabricator or the Society. Fillet welding procedure tests shall be in accordance with the Society's practice. In such cases consumables shall be selected which exhibit satisfactory impact properties.

5.4.1 Welding procedure tests for piping shall be carried out and shall be similar to those detailed for cargo tanks in [5.3]. Unless otherwise specially agreed with the Society, the tests shall satisfy the requirements given in [5.3.5].

5.5 Production weld tests 5.5.1 For all cargo tanks and process pressure vessels, except integral and membrane tanks, production weld tests shall generally be performed for approximately each 50 m of butt-weld joints and shall be representative of each welding position. For secondary barriers, the same type production tests as required for primary tanks shall be performed, except that the number of tests may be reduced, subject to agreement with the Society. Tests, other than those specified in [5.5.2] to [5.5.5] may be required for cargo tanks or secondary barriers at the discretion of the Society. 5.5.2 The production tests for type A and type B independent tanks and semi-membrane tanks shall include bend tests and, where required for procedure tests, one set of three Charpy V-notch tests. The tests shall be made for each 50 m of weld. The Charpy V-notch tests shall be made with specimens having the notch alternately located in the center of the weld and in the heat-affected zone (most critical location based on procedure qualification results). For austenitic stainless steel, all notches shall be in the center of the weld. 5.5.3 For type C independent tanks and process pressure vessels, transverse weld tensile tests are required in addition to the tests listed in [5.5.2]. The test requirements are specified in [5.3.5]. 5.5.4 The quality assurance/quality control programme shall ensure the continued conformity of the production welds as defined in the fabricators quality manual. 5.5.5 Production tests for integral and membrane tanks shall be specially agreed with the Society. The test requirements for integral and membrane tanks are the same as the applicable test requirements listed in [5.3].

5.6 Non-destructive testing 5.6.1 All test procedures and acceptance standards shall be in accordance with Pt.2 Ch.4, unless the designer specifies a higher standard in order to meet design assumptions. Radiographic testing shall be used, in principle, to detect internal defects. However, an approved ultrasonic test procedure in lieu of radiographic testing may be conducted, but, in addition, supplementary radiographic testing at selected locations shall be carried out to verify the results. Radiographic and ultrasonic testing records shall be retained. 5.6.2 For type A independent tanks and semi-membrane tanks, where the design temperature is below -20°C, and for type B independent tanks, regardless of temperature, all full penetration butt welds of the shell plating of cargo tanks shall be subjected to non-destructive testing suitable to detect internal defects over their full length. Ultrasonic testing in lieu of radiographic testing may be carried out under the same conditions as described in [5.6.1]. 5.6.3 Where the design temperature is higher than -20°C, all full penetration butt welds in way of intersections and at least 10 % of the remaining full penetration welds of tank structures shall be subjected to radiographic testing or ultrasonic testing under the same conditions as described in [5.6.1]. 5.6.4 In each case, the remaining tank structure, including the welding of stiffeners and other fittings and attachments, shall be examined by magnetic particle or dye penetrant methods, as considered necessary.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 124

Part 5 Chapter 7 Section 6

5.4 Welding procedure tests for piping

1)

total non-destructive testing referred to in Sec.22 [2.8.4]: 1) 2)

radiographic testing: all butt welds over their full length non-destructive testing for surface crack detection: 1) 2)

2)

all welds over 10 % of their length reinforcement rings around holes, nozzles, etc., over their full length.

As an alternative, ultrasonic testing as described in [5.6.1] may be accepted as a partial substitute for the radiographic testing. In addition, the Society may require total ultrasonic testing on welding of reinforcement rings around holes, nozzles, etc. partial non-destructive testing referred to in Sec.22 [2.8.4]: 1)

Radiographic testing: 1) 2) 3)

2)

all butt-welded crossing joints and at least 10 % of the full length of butt welds at selected positions uniformly distributed non-destructive testing for surface crack detection reinforcement rings around holes, nozzles, etc., over their full length.

Ultrasonic testing: as may be required by the Society in each instance.

5.6.6 The quality assurance/quality control programme shall ensure the continued conformity of the nondestructive testing of welds, as defined in the fabricators quality manual. 5.6.7 Inspection of piping shall be carried out in accordance with the requirements of Sec.5. 5.6.8 The secondary barrier shall be non-destructive tested for internal defects as considered necessary. Where the outer shell of the hull is part of the secondary barrier, all sheer strake butts and the intersections of all butts and seams in the side shell shall be tested by radiographic testing.

6 Other requirements for construction in metallic materials 6.1 General 6.1.1 Inspection and non-destructive testing of welds shall be in accordance with the requirements of [5.5] and [5.6]. Where higher standards or tolerances are assumed in the design, they shall also be satisfied.

6.2 Independent tank 6.2.1 For type C tanks and type B tanks primarily constructed of bodies of revolution, the tolerances relating to manufacture, such as out-of-roundness, local deviations from the true form, welded joints alignment and tapering of plates having different thicknesses, shall comply with recognized standards as accepted by the Society. The tolerances shall also be related to the buckling analysis referred to in Sec.21 [3.2.3] and Sec.22 [2.1.3]. 6.2.2 For type C tanks of carbon and carbon-manganese steel, post-weld heat treatment shall be performed after welding, if the design temperature is below -10°C. Post-weld heat treatment in all other cases and for materials other than those mentioned above, shall be to recognized standards. The soaking temperature and holding time shall be to the recognized standards.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 125

Part 5 Chapter 7 Section 6

5.6.5 For type C independent tanks, the extent of non-destructive testing shall be total or partial according to recognized standards, but the controls to be carried out shall not be less than the following:

.1

Complicated welded pressure vessel parts such as sumps or domes with nozzles, with adjacent shell plates shall be heat treated before they are welded to larger parts of the pressure vessel.

.2

The mechanical stress relieving process shall preferably be carried out during the hydrostatic pressure test required by Sec.22 [2], by applying a higher pressure than the test pressure required by Sec.22 [2.1.2], The pressurizing medium shall be water.

.3 .4

For the water temperature, Sec.22 [2.1.1], applies.

.5

The maximum stress relieving pressure shall be held for 2 h per 25 mm of thickness, but in no case less than 2 h.

.6

The upper limits placed on the calculated stress levels during stress relieving shall be the following:

Stress relieving shall be performed while the tank is supported by its regular saddles or supporting structure or, when stress relieving cannot be carried out on board, in a manner which will give the same stresses and stress distribution as when supported by its regular saddles or supporting structure.

.1 .2

equivalent general primary membrane stress: 0.9 ReH equivalent stress composed of primary bending stress plus membrane stress: 1.35 ReH,

where ReH is the specific lower minimum yield stress or 0.2 % proof stress at test temperature of the steel used for the tank.

.7

Strain measurements will normally be required to prove these limits for at least the first tank of a series of identical tanks built consecutively. The location of strain gauges shall be included in the mechanical stress relieving procedure to be submitted in accordance with [6.2.3].

.8

The test procedure shall demonstrate that a linear relationship between pressure and strain is achieved at the end of the stress relieving process when the pressure is raised again up to the design pressure.

.9

High-stress areas in way of geometrical discontinuities such as nozzles and other openings shall be checked for cracks by dye penetrant or magnetic particle inspection after mechanical stress relieving. Particular attention in this respect shall be paid to plates exceeding 30 mm in thickness.

.10

Steels which have a ratio of yield stress to ultimate tensile strength greater than 0.8 shall generally not be mechanically stress relieved. If, however, the yield stress is raised by a method giving high ductility of the steel, slightly higher rates may be accepted upon consideration in each case.

.11

Mechanical stress relieving cannot be substituted for heat treatment of cold formed parts of tanks, if the degree of cold forming exceeds the limit above which heat treatment is required.

.12

The thickness of the shell and heads of the tank shall not exceed 40 mm. Higher thicknesses may be accepted for parts which are thermally stress relieved.

.13

Local buckling shall be guarded against, particularly when tori-spherical heads are used for tanks and domes, and:

.14

The procedure for mechanical stress relieving shall be to a recognized standard.

6.3 Secondary barriers 6.3.1 During construction, the requirements for testing and inspection of secondary barriers shall be approved or accepted by the Society (see Sec.4 [2.4.2] .5 and .6).

6.4 Semi-membrane tanks 6.4.1 For semi-membrane tanks, the relevant requirements in [6] for independent tanks or for membrane tanks shall be applied as appropriate.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 126

Part 5 Chapter 7 Section 6

6.2.3 In the case of type C tanks and large cargo pressure vessels of carbon or carbon-manganese steel, for which it is difficult to perform the heat treatment, mechanical stress relieving by pressurizing may be carried out as an alternative to the heat treatment and subject to the following conditions:

6.5.1 The quality assurance/quality control programme shall ensure the continued conformity of the weld procedure qualification, design details, materials, construction, inspection and production testing of components. These standards and procedures shall be developed during the prototype testing programme.

7 Non-metallic materials 7.1 General 7.1.1 The information in App.A is given for guidance in the selection and use of these materials, based on the experience to date.

8 Hull materials 8.1 Inner hull structure 8.1.1 The inner hull structure includes inner bottom plating, longitudinal bulkhead plating, transverse bulkhead plating, floors, webs, stringers and all attached stiffening members. 8.1.2 Materials in the inner hull structure which are subject to reduced temperature due to the cargo, and which do not form part of the secondary barrier, shall be in accordance with Table 5 if the steel significant temperature calculated according to Sec.4 [5.1] is below 0°C.

8.2 Outer hull structure 8.2.1 The outer hull structure includes the shell and deck plating of the ship and all stiffeners attached thereto. 8.2.2 The materials in the outer hull structure shall be in accordance with Pt.3 Ch.1 Sec.2, unless then calculated temperature of the material in the design condition (Sec.4 [5.1]) is below -5°C due to the effect of the low temperature cargo, in which case the material shall be in accordance with Table 5 assuming the ambient air and sea temperatures of 5°C and 0°C respectively. 8.2.3 In the design condition the complete or partial secondary barrier is assumed to be at the cargo temperature at atmospheric pressure and for tanks without secondary barriers, the primary barrier is assumed to be at the cargo temperature.

8.3 Secondary barrier 8.3.1 Hull material forming the secondary barrier shall be in accordance with Table 2. Metallic materials used in secondary barriers not forming part of the hull structure should be in accordance with Table 2 or Table 3 as applicable. Insulation materials forming a secondary barrier shall comply with the requirements of Sec.4 [2.8]. Where the secondary barrier is formed by the deck or side shell plating, the material grade required by Table 2 should be carried into the adjacent deck or side shell plating, where applicable to a suitable extent.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 127

Part 5 Chapter 7 Section 6

6.5 Membrane tanks

9.1 General requirements 9.1.1 General requirements regarding marking of valves are given in Pt.4 Ch.6 Sec.3. 9.1.2 Language All marking shall be in the language of the registration country of the ship. On ships in international service, corresponding marking is also to be made in a language appropriate for the ship's normal route, preferably in English. 9.1.3 Marking plates Marking plates shall be made of corrosion-resistant materials, and shall be permanently fixed to valves handles, flanges or similar parts. Markings, bolt holes etc. in the tanks themselves shall be avoided. The lettering shall be impressed on the marking plate in letters of at least 5 mm height. The marking plates shall be placed in easily visible positions and shall not be painted. 9.1.4 Marking of tanks, pipes and valves Every independent tank type C shall have a marking plate reading as follows: — — — — — — — —

tank number design pressure in MPa 3 maximum cargo density in kg/m lowest permissible temperature in °C 3 capacity of the tank in m at 98% filled or at maximum filling test pressure in MPa name of builder year of construction.

The marking plate may also be used for the necessary markings of identification. For definitions of: — design pressure, see Sec.1 [3.1] — test pressure, see Sec.4 [5.2.3] .1. All valves shall be clearly marked to indicate where the connected pipelines lead. 9.1.5 Marking of tank connections All intake and outlet connections, except safety valves, manometers and liquid level indicators, shall be clearly marked to indicate whether the connection leads to the vapour or liquid phase of the tank.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 128

Part 5 Chapter 7 Section 6

9 Marking of tanks, pipes and valves

1 Methods of control 1.1 General requirements 1.1.1 With the exception of tanks including cargo system that are designed to withstand full gauge vapour pressure of the cargo under conditions of the upper ambient design temperatures, cargo tanks' pressure and temperature shall be maintained at all times within their design range by either one, or a combination of, the following methods:

.1 .2 .3 .4

re-liquefaction of cargo vapours thermal oxidation of vapours, i.e. gas combustion pressure accumulation, and liquid cargo cooling.

1.1.2 For certain cargoes, where required by Sec.17, the cargo containment system shall be capable of withstanding the full vapour pressure of the cargo under conditions of the upper ambient design temperatures, irrespective of any system provided for dealing with boil-off gas. 1.1.3 Venting of the cargo to maintain cargo tank pressure and temperature is not acceptable except in emergency situations. The administration may permit certain cargoes to be controlled by venting cargo vapours to the atmosphere at sea. This may also be permitted in port with the permission of the port administration.

2 Design of systems 2.1 General requirements 2.1.1 For normal service, the upper ambient design temperature shall be: — sea: 32°C — air: 45°C. For service in particularly hot or cold zones, these design temperatures shall be increased or decreased, to the satisfaction of the Society. The overall capacity of the system shall be such that it can control the pressure within the design conditions without venting to atmosphere. 2.1.2 The design boil-off rate is the maximum evaporated cargo from the cargo tanks at stable pressure and temperature below the cargo tanks PRVs setting as given in [1.1.1] under the conditions given in [2.1.1]. Boil handling can be arranged as given in Table 1.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 129

Part 5 Chapter 7 Section 7

SECTION 7 CARGO PRESSURE - TEMPERATURE CONTROL

Table 1 Boil-off handling and redundancy requirements for methane when use of reliquefaction systems or thermal oxidation vapour systems Propulsion

Primary

Secondary

diesel

re-liquefaction

re-liquefaction

diesel

re-liquefaction

GCU

Capacity and redundancy 2 × 100% design boil-off gas capacity re-liquefaction units. Common cold box may be accepted. 1 × 100% design boil-off gas capacity re-liquefaction unit. 1 × 100% design boil-off gas capacity GCU. 1 × 100% design boil-off gas capacity GCU with redundant fans,

diesel

GCU

GCU

igniters, gas flow control valves and control systems, or 2 × 100% design boil-off gas capacity independent GCUs, or 3 × 50% design boil-off gas capacity independent GCUs 1 × 100% design boil-off gas capacity GCU with redundant fans,

dual fuel diesel and gas only

GCU

GCU

igniters, gas flow control valves and control systems, or 2 × 100% design boil-off gas capacity independent GCUs; or 3 × 50% design boil-off gas capacity independent GCUs

Note that gas fired boiler or inert gas generator can be used as thermal oxidation vapour system (GCU). Other methods as given in [1.1.1] can also be used for methane (LNG). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3 Re-liquefaction of cargo vapours 3.1 General requirements 3.1.1 The re-liquefaction system may be arranged in one of the following ways:

.1 .2

A direct system where evaporated cargo is compressed, condensed and returned to the cargo tanks.

.3

A combined (cascade) system where evaporated cargo is compressed and condensed in a cargo/ refrigerant heat exchanger and returned to the cargo tanks, and:

.4

If the re-liquefaction system produces a waste stream containing methane during pressure control operations within the design conditions, these waste gases, as far as reasonably practicable, are disposed off without venting to atmosphere.

An indirect system where cargo or evaporated cargo is cooled or condensed by refrigerant without being compressed.

The requirements of Sec.17 and Sec.19 may preclude the use of one or more of these systems or may specify the use of a particular system. 3.1.2 For re-liquefaction the control and monitoring requirements for such installations is given in Sec.13 [12].

3.2 Compatibility 3.2.1 Refrigerants used for re-liquefaction shall be compatible with the cargo they may come into contact with. In addition, when several refrigerants are used and may come into contact, they shall be compatible with each other.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 130

Part 5 Chapter 7 Section 7

Guidance note:

4 Thermal oxidation of vapours, i.e gas combustion 4.1 General 4.1.1 Maintaining the cargo tank pressure and temperature by means of thermal oxidation of cargo vapours, as defined in Sec.1 [3.1] and Sec.16 [2]. This is permitted only for LNG cargoes. In general:

.1

Thermal oxidation systems shall exhibit no externally visible flame and shall maintain the uptake exhaust temperature below 535°C.

.2

Arrangement of spaces where oxidation systems are located shall comply with Sec.16 [3] and supply systems shall comply with Sec.16 [4].

.3

If waste gases coming from any other system shall be burnt, the oxidation system shall be designed to accommodate all anticipated feed gas compositions.

4.1.2 Thermal oxidation of vapour system may be accepted as only method for cargo tanks' pressure and temperature control on following conditions. — The system is able to handle applicable design boil-off rate, i.e. design boil-off minus hotel loads. — Redundancy is arranged for fans (combustion and dilution), igniters, gas flow control valve(s) and control system. Guidance note: The amount of boil-off gas that can be consumed at all ship operations including harbour operations is defined as the base load (hotel load). This base load may be subtracted from the maximum design boil-off rate to establish the capacity of the gas combustion units. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.3 The control and monitoring requirements for such installations is given in Sec.13 [12].

4.2 Thermal oxidation systems 4.2.1 Thermal oxidation system shall comply with the following:

.1 .2

each thermal oxidation system shall have a separate uptake each thermal oxidation system shall have a dedicated forced draught system, and

.3

combustion chambers and uptakes of thermal oxidation systems shall be designed to prevent any accumulation of gas.

4.3 Burners 4.3.1 Burners shall be designed to maintain stable combustion under all design firing conditions.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 131

Part 5 Chapter 7 Section 7

3.2.2 The heat exchange may take place either remotely from the cargo tank or by cooling coils fitted inside or outside the cargo tank.

4.4.1 Suitable devices shall be installed and arranged to ensure that gas flow to the burner is cut off unless satisfactory ignition has been established and maintained. 4.4.2 Each oxidation system shall have provision to manually isolate its gas fuel supply from a safely accessible position. 4.4.3 Provision shall be made for automatic purging the gas supply piping to the burners by means of an inert gas, after the extinguishing of these burners. 4.4.4 In case of flame failure of all operating burners for gas or oil or for a combination thereof, the combustion chambers of the oxidation system shall be automatically purged before relighting. 4.4.5 Arrangements shall be made to enable the combustion chamber to be manually purged. 4.4.6 Control and monitoring requirements are given in Sec.13 [11].

5 Pressure accumulation systems 5.1 General requirements 5.1.1 The containment system insulation, design pressure or both shall be adequate to provide for a suitable margin for the operating time and temperatures involved. No additional pressure and temperature control system is required.

6 Liquid cargo cooling 6.1 General requirements 6.1.1 The bulk cargo liquid may be refrigerated by coolant circulated through coils fitted either inside the cargo tank or onto the external surface of the cargo tank.

7 Segregation 7.1 General requirements 7.1.1 Where two or more cargoes that may react chemically in a dangerous manner, are carried simultaneously, separate systems as defined in Sec.1 [3.1], each complying with availability criteria as specified in [8], shall be provided for each cargo. For simultaneous carriage of two or more cargoes that are not reactive to each other but where, due to properties of their vapour, separate systems are necessary, separation may be by means of isolation valves.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 132

Part 5 Chapter 7 Section 7

4.4 Safety

8.1 General requirements 8.1.1 The availability of the system and its supporting auxiliary services shall fulfil following requiements:

.1

In case of a single failure of a mechanical non-static component or a component of the control systems, the cargo tanks' pressure and temperature can be maintained within their design range without affecting other essential services.

.2 .3

Redundant piping systems are not required.

.4

For any cargo heating or cooling medium, provisions shall be made to detect the leakage of toxic or flammable vapours into an otherwise non-hazardous area or overboard in accordance with Sec.13 [6]. Any vent outlet from this leak detection arrangement shall be to a safe location and be fitted with a flame screen.

Heat exchangers that are solely necessary for maintaining the pressure and temperature of the cargo tanks within their design ranges shall have a stand- by heat exchanger, unless they have a capacity in excess of 25% of the largest required capacity for pressure control and they can be repaired on board without external resources. Where an additional and separate method of cargo tank pressure and temperature control is fitted that is not reliant on the sole heat exchanger, then a standby heat exchanger is not required, and:

9 Cargo heating arrangements 9.1 General requirements 9.1.1 Requirements for water systems and steam systems are identical to those of Pt.4 Ch.6 Sec.5, unless otherwise stated. 9.1.2 The heating media shall be compatible with the cargo and comply with the temperature requirements given in Sec.5 [1.1.4]. 9.1.3 For heating of cargoes where gas detection with regard to toxic effects are required by column f in the list of products in Sec.17, the heating medium shall not be returned to the machinery space. For heating of other cargoes, the medium may be returned to the engine room provided a degassing tank with gas detector is arranged, See Sec.13 [6.1.2] .6. The degassing tank shall be located in the cargo area.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 133

Part 5 Chapter 7 Section 7

8 Availability

1 General 1.1 General requirements 1.1.1 All cargo tanks shall be provided with a pressure relief system appropriate to the design of the cargo containment system and the cargo being carried. Hold space and interbarrier spaces, which may be subject to pressures beyond their design capabilities, shall also be provided with a suitable pressure relief system. Pressure control systems specified in Sec.7 shall be independent of the pressure relief systems.

2 Pressure relief systems 2.1 General requirements 2.1.1 Cargo tanks, including deck tanks, shall be fitted with a minimum of two pressure relief valves (PRVs), each being of equal size within manufacturer's tolerances and suitably designed and constructed for the prescribed service. 2.1.2 Interbarrier spaces shall be provided with pressure relief devices: — For membrane systems, the designer shall demonstrate adequate sizing of interbarrier space PRVs. — For type B tanks the relieving capacity of pressure relief devices of interbarrier spaces shall be determined on the basis of the leakage rate determined in accordance with Sec.4 [2.5.2] or as given for type A tanks in [5]. — For type A tanks, see requirements given in [5]. 2.1.3 The setting of the PRVs shall not be higher than the vapour pressure that has been used in the design of the tank. Where two or more PRVs are fitted, valves comprising not more than 50% of the total relieving capacity may be set at a pressure up to 5% above MARVS to allow sequential lifting, minimizing unnecessary release of vapour. 2.1.4 The following temperature requirements apply to PRVs fitted to pressure relief systems:

.1

PRVs on cargo tanks with a design temperature below 0°C shall be designed and arranged to prevent their becoming inoperative due to ice formation

.2

the effects of ice formation due to ambient temperatures shall be considered in the construction and arrangement of PRVs

.3

PRVs shall be constructed of materials with a melting point (solidus temperature) above 925°C. Lower melting point materials for internal parts and seals may be accepted, provided that fail-safe operation of the PRV is not compromised, and

.4

sensing and exhaust lines on pilot operated relief valves shall be of suitably robust construction to prevent damage.

2.1.5 Valve testing 2.1.5.1 PRVs shall be prototype tested. Type tests shall include:

.1 .2

verification of relieving capacity cryogenic testing when operating at design temperatures colder than -55°C

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 134

Part 5 Chapter 7 Section 8

SECTION 8 VENT SYSTEM FOR CARGO CONTAINMENT SYSTEM

seat tightness testing, and pressure containing parts are pressure tested to at least 1.5 times the design pressure. Guidance note: PRV can be tested according to ISO 21013-1:2008 – Cryogenic vessels – Pressure-relief accessories for cryogenic service – part 1: Recloseable pressure-relief valves; and ISO 4126-1; 2004/2013 Safety devices for protection against excessive pressure – part 1 and part 4: Safety valves. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.5.2 Each PRV shall be tested to ensure that:

.1

it opens at the prescribed pressure setting, with an allowance not exceeding ± 10% for 0 to 0.15 MPa, ± 6% for 0.15 to 0.3 MPa, ± 3% for 0.3 MPa and above

.2 .3

seat tightness at 90% of the set pressure is acceptable, and pressure containing parts shall withstand at least 1.5 times the design pressure.

2.1.6 PRVs shall be set and sealed by the Society, and recorded by a sealing certificate, including the valves' set pressure, shall be retained on board the ship. The set pressure shall be sealed by the use of a robust non-corrosive wire. 2.1.7 Cargo tanks may be permitted to have more than one relief valve set pressure in the following cases:

.1

installing two or more properly set and sealed PRVs and providing means, as necessary, for isolating the valves not in use from the cargo tank, or

.2

installing relief valves whose settings may be changed by the use of a previously approved device not requiring pressure testing to verify the new set pressure. All other valve adjustments shall be sealed.

2.1.8 Changing the set pressure under the provisions of [2.1.7] and the corresponding resetting of the alarms referred to in Sec.13 [4.1.3] shall be carried out under the supervision of the master in accordance with approved procedures and as specified in the ship's operating manual. Changes in set pressure shall be recorded in the ship's log and a sign shall be posted in the cargo control room, if provided, and at each relief valve, stating the set pressure. 2.1.9 In the event of a failure of a cargo tank PRV, a safe means of emergency isolation shall be available:

.1 .2 .3

Procedures shall be provided and included in the cargo operations manual, see Sec.18 [1].

.4

The tank shall not be loaded until the full relieving capacity is restored.

The procedures shall allow only one of the cargo tanks installed PRVs to be isolated. Isolation of the PRV shall be carried out under the supervision of the master. This action shall be recorded in the ship's log and a sign posted in the cargo control room, if provided, and at the PRV. Guidance note: The safe means of emergency isolation should be provided so that a PRV can be isolated on a temporary basis to reseat or repair the valve before putting the PRV back into service. Such means of emergency isolation should be installed in a manner that does not allow their inadvertent operation. Reference is made to MSC.1/Circ.1559 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.10 Each PRV installed on a cargo tank shall be connected to a venting system, which shall be:

.1 .2

so constructed that the discharge will be unimpeded and directed vertically upwards at the exit arranged to minimize the possibility of water or snow entering the vent system

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 135

Part 5 Chapter 7 Section 8

.3 .4

arranged such that the height of vent exits shall not be less than B/3 or 6 m, whichever is the greater, above the weather deck, and

.4

6 m above working areas and walkways.

2.1.11 Cargo PRV vent exits shall be arranged at a distance at least equal to B or 25 m, whichever is less, from the nearest air intake, outlet or opening to accommodation spaces, service spaces and control stations, other non-hazardous areas, exhaust outlet from machinery or from furnace installations onboard. For ships less than 90 m in length, smaller distances may be permitted. 2.1.12 All other vent outlets connected to the cargo containment system shall be arranged at a distance of at least 10 m from the nearest air intake, outlet or opening to accommodation spaces, service spaces and control stations, or other non-hazardous areas. 2.1.13 All other cargo vent outlets not dealt with in other sections shall be arranged in accordance with [2.1.10], [2.1.11] and [2.1.12]. Means shall be provided to prevent liquid overflow from vent mast outlets, due to hydrostatic pressure from spaces to which they are connected. Vent outlets for systems containing flammable and/or toxic gases (like refrigerants) shall also be handled as given above. 2.1.14 If cargoes that react in a dangerous manner with each other are carried simultaneously, a separate pressure relief system shall be fitted for each one. 2.1.15 In the vent piping system, means for draining liquid from places where it may accumulate shall be provided, preferably in the form of special condensation pots. The PRVs and piping shall be arranged so that liquid can, under no circumstances, accumulate in or near the PRVs. 2.1.16 Suitable protection screens of not more than 13 mm square mesh shall be fitted on vent outlets to prevent the ingress of foreign objects without adversely affecting the flow. Other requirements for protection screens apply when carrying specific cargoes, see Sec.17 [1.8] and Sec.17 [11]. 2.1.17 All vent piping shall be designed and arranged not to be damaged by the temperature variations to which it may be exposed, forces due to flow or the ship's motions. 2.1.18 PRVs shall be connected to the highest part of the cargo tank above deck level. PRVs shall be positioned on the cargo tank so that they will remain in the vapour phase at the maximum filling limit (FL) as defined in Sec.15, under conditions of 15° list and 0.015LLL trim, where LLL is defined in Sec.1 [3.1].29. 2.1.19 The adequacy of the vent system fitted on tanks loaded in accordance with Sec.15 [1.5.2] shall be demonstrated using Assembly resolution A.829(19) on Guidelines for the evaluation of the adequacy of type C tank vent systems. If the vent system is found acceptable, a certificate of increased loading limit will be issued by the Society. For the purposes of this paragraph, vent system means:

.1 .2 .3

the tank outlet and the piping to the PRV the PRV the piping from the PRVs to the location of discharge to the atmosphere, including any interconnections and piping that joins other tanks.

3 Vacuum protection systems 3.1 General requirements 3.1.1 Cargo tanks not designed to withstand a maximum external pressure differential of 0.025 MPa, or tanks that cannot withstand the maximum external pressure differential that can be attained at maximum

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 136

Part 5 Chapter 7 Section 8

.3

.1

two independent pressure switches to sequentially alarm and subsequently stop all suction of cargo liquid or vapour from the cargo tank and refrigeration equipment, if fitted, by suitable means at a pressure sufficiently below the maximum external designed pressure differential of the cargo tank, or

.2

vacuum relief valves with a gas flow capacity at least equal to the maximum cargo discharge rate per cargo tank, set to open at a pressure sufficiently below the external design differential pressure of the cargo tank.

3.1.2 Subject to the requirements of Sec.17, the vacuum relief valves shall admit an inert gas, cargo vapour or air to the cargo tank and shall be arranged to minimize the possibility of the entrance of water or snow. If cargo vapour is admitted it shall be from a source other than the cargo vapour lines. 3.1.3 The vacuum protection system shall be capable of being tested to ensure that it operates at the prescribed pressure.

4 Sizing of pressure relieving system 4.1 Sizing of pressure relief valves 4.1.1 PRVs shall have a combined relieving capacity for each cargo tank to discharge the greatest of the following, with not more than a 20% rise in cargo tank pressure above the MARVS:

.1

the maximum capacity of the cargo tank inerting system if the maximum attainable working pressure of the cargo tank inerting system exceeds the MARVS of the cargo tanks, or

.2

vapours generated under fire exposure computed using the following formula: 0.82

Q = FGA where: Q

3

= minimum required rate of discharge of air in m /s at standard conditions of 273.15 Kelvin (K) and 0.1013 MPa; fire exposure factor for different cargo types:

F

— 1.0 for tanks without insulation located on deck — 0.5 for tanks above the deck when insulation is approved by the Society. Approval will be based on the use of a fireproofing material, the thermal conductance of insulation, and its stability under fire exposure — 0.5 for uninsulated independent tanks installed in holds = — 0.2 for insulated independent tanks in holds or uninsulated independent tanks in insulated holds — 0.1 for insulated independent tanks in inerted holds or uninsulated independent tanks in inerted, insulated holds — 0.1 for membrane and semi-membrane tanks. — For independent tanks partly protruding through the weather decks, the fire exposure factor shall be determined on the basis of the surface areas above and below deck.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 137

Part 5 Chapter 7 Section 8

discharge rates with no vapour return into the cargo tanks, or by operation of a cargo refrigeration system, or by thermal oxidation, shall be fitted with one of the following:

=

G

=

2

external surface area of the tank in m , as defined in Sec.1 [3.1], for different tank types, as shown in Figure 1: gas factor taken equal to:

with: T

=

temperature in degrees Kelvin at relieving conditions, i.e. 120% of the pressure at which the pressure relief valve is set

L

=

latent heat of the material being vaporized at relieving conditions, in kJ/kg a constant based on relation of specific heats k and is calculated as follows:

D

=

k

= ratio of specific heats at relieving conditions, and the value of which is between 1.0 and 2.2. If k is not known, D = 0.606 shall be used

Z

= compressibility factor of the gas at relieving conditions; if not known, Z = 1.0 shall be used, and

M

= molecular mass of the product.

The gas factor of each cargo to be carried shall be determined and the highest value shall be used for PRV sizing.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 138

Part 5 Chapter 7 Section 8

A

Part 5 Chapter 7 Section 8 Figure 1 External surface area of tank

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 139

L min , for non-tapered tanks, is the smaller of the horizontal dimensions of the flat bottom of the tank. For tapered tanks, as would be used for the forward tank, L min is the smaller of the length and the average width. For prismatic tanks whose distance between the flat bottom of the tank and bottom of the hold space is equal to or less than L min /10: A = external surface area minus flat bottom surface area. For prismatic tanks whose distance between the flat bottom of the tank and bottom of the hold space is greater than L min /10:A = external surface area. Reference is made to MSC.1/Circ.1559

.3

---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

The required mass flow of air in kg/s at relieving conditions is given by: M

air

= Q · ρair,

where:

ρair ρair

= density of air at 273.15 K and 0.1013 MPa. 3

= 1.293 kg/m .

4.2 Sizing of vent pipe system 4.2.1 Pressure losses upstream and downstream of the PRVs, shall be taken into account when determining their size to ensure the flow capacity required by [4.1].

4.3 Upstream pressure losses 4.3.1 The pressure drop in the vent line from the tank to the PRV inlet shall not exceed 3% of the valve set pressure at the calculated flow rate, in accordance with [4.1]. Guidance note: An inlet pressure drop above 3% of MARVS may be accepted for pilot operated valves with remote sensing lines which are not affected by the inlet pipe pressure drops providing the sizing calculation includes the effect of inlet pressure drop. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.3.2 Pilot-operated PRVs shall be unaffected by inlet pipe pressure losses when the pilot senses directly from the tank dome. 4.3.3 Pressure losses in remotely sensed pilot lines shall be considered for flowing type pilots.

4.4 Downstream pressure losses 4.4.1 Where common vent headers and vent masts are fitted, calculations shall include flow from all attached PRVs. 4.4.2 The built-up back pressure in the vent piping from the PRV outlet to the location of discharge to the atmosphere, and including any vent pipe interconnections that join other tanks, shall not exceed the following values: — for unbalanced PRVs: 10% of MARVS — for balanced PRVs: 30% of MARVS — for pilot operated PRVs: 50% of MARVS. Alternative values provided by the PRV manufacturer may be accepted.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 140

Part 5 Chapter 7 Section 8

Guidance note:

5 Pressure relief devices 5.1 General 5.1.1 If independent tanks are surrounded by a secondary barrier, the spaces between the primary and secondary barriers shall be equipped with blow-out membranes or pressure relief devices which shall open when the pressure exceeds 0.025 MPa. Guidance note: For hold spaces where insulation is on the hull side and not on the cargo tank, special considerations related to the necessary pressure relief arrangement will be taken to suit the applicable design. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.1.2 The combined relieving capacity of the pressure relief devices for interbarrier spaces surrounding type A independent cargo tanks where the insulation is fitted to the cargo tanks may be determined by the following formula:

where: 3

Q sa

= minimum required discharge rate of air in m /s at standard conditions of 273.15 K, 0.1013 MPa

Ac

= design crack opening area in m

δ δ t ℓ

= maximum crack opening width in m

h ρ ρv

= maximum liquid height above tank bottom plus 10 × MARVS in m

2

= 0.2 t m = thickness of tank bottom plating in m = design crack length in m equal to the diagonal of the largest plate panel of the tank bottom, see Figure 2 3

= density of product liquid phase in kg/m , at the set pressure of the interbarrier space relief device 3

= density of product vapour phase in kg/m , at the set pressure of the interbarrier space relief device and a temperature of 273.15 K

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 141

Part 5 Chapter 7 Section 8

4.4.3 To ensure stable PRV operation, the blow-down shall not be less than the sum of the inlet pressure loss and 0.02 MARVS at the rated capacity.

Part 5 Chapter 7 Section 8

girder

b

(t) typical plate panel bxs

girder

S

S

S

stiffener Figure 2 Design crack length, ℓ Guidance note: See IACS UI GC9. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.1.3 The pressure relief hatches covered by [5.1.2] shall be constructed to avoid risk of damage by expected external forces. 5.1.4 Pressure relief devices covered by [5.1.2] need not be arranged to comply with the requirements of [2.2.7], [2.2.8] and [2.2.9] related to vent outlets.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 142

1 Atmosphere control within the cargo containment system 1.1 General requirements 1.1.1 A piping system shall be arranged to enable each cargo tank to be safely gas-freed, and to be safely filled with cargo vapour from a gas-free condition. The system shall be arranged to minimize the possibility of pockets of gas or air remaining after changing the atmosphere. 1.1.2 For flammable cargoes, the system shall be designed to eliminate the possibility of a flammable mixture existing in the cargo tank during any part of the atmosphere change operation by utilizing an inerting medium as an intermediate step. Guidance note: All cargo tanks operations should be carried out in such a way that flammable atmosphere within the tank will not occur. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.3 Piping systems that may contain flammable cargoes shall comply with [1.1.1] and [1.1.2]. 1.1.4 A sufficient number of gas sampling points shall be provided for each cargo tank and cargo piping system to adequately monitor the progress of atmosphere change. Gas sampling connections shall be fitted with a single valve above the main deck, sealed with a suitable cap or blank. See Sec.5 [6.4]. 1.1.5 Inert gas utilized in these procedures may be provided from the shore or from the ship. 1.1.6 Gas freeing system shall not be permanently connected to cargo tanks or cargo piping system. Such connection shall be portable means, like flexible hoses or spool pieces.

1.2 Atmosphere control within the hold spaces (cargo containment systems other than type C independent tanks) 1.2.1 Interbarrier and hold spaces associated with cargo containment systems for flammable gases requiring full or partial secondary barriers shall be inerted with a suitable dry inert gas and kept inerted with make-up gas provided by a shipboard inert gas generation system, or by shipboard storage, which shall be sufficient for normal consumption for at least 30 days. 1.2.2 Alternatively, subject to the restrictions specified in Sec.17, the spaces referred to in [1.2.1] requiring only a partial secondary barrier may be filled with dry air provided that the ship maintains a stored charge of inert gas or is fitted with an inert gas generation system sufficient to inert the largest of these spaces, and provided that the configuration of the spaces and the relevant vapour detection systems, together with the capability of the inerting arrangements, ensures that any leakage from the cargo tanks will be rapidly detected and inerting effected before a dangerous condition can develop. Equipment for the provision of sufficient dry air of suitable quality to satisfy the expected demand shall be provided. 1.2.3 For non-flammable gases, the spaces referred to in [1.2.1] and [1.2.2] may be maintained with a suitable dry air or inert atmosphere. 1.2.4 For membrane containments which has need for continues supply of inert gas (nitrogen) to the containment system redundancy on all active components should be provided, if not shipboard storage is provided.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 143

Part 5 Chapter 7 Section 9

SECTION 9 CARGO CONTAINMENT SYSTEM ATMOSPHERIC CONTROL

1.3.1 Spaces surrounding cargo tanks that do not have secondary barriers shall be filled with suitable dry inert gas or dry air and be maintained in this condition with make-up inert gas provided by a shipboard inert gas generation system, shipboard storage of inert gas, or with dry air provided by suitable air drying equipment. If the cargo is carried at ambient temperature, the requirement for dry air or inert gas is not applicable.

1.4 Inerting 1.4.1 Inerting refers to the process of providing a non-combustible environment. Inert gases shall be compatible chemically and operationally at all temperatures likely to occur within the spaces and the cargo. The dew points of the gases shall be taken into consideration. 1.4.2 Where inert gas is also stored for fire-fighting purposes, it shall be carried in separate containers and shall not be used for cargo services. 1.4.3 Where inert gas is stored at temperatures below 0°C, either as a liquid or as a vapour, the storage and supply system shall be designed so that the temperature of the ship's structure is not reduced below the limiting values imposed on it. 1.4.4 Arrangements to prevent the backflow of cargo vapour into the inert gas system that are suitable for the cargo carried, shall be provided. If such plants are located in machinery spaces or other spaces outside the cargo area, two non-return valves or equivalent devices and, in addition, a removable spool piece shall be fitted in the inert gas main in the cargo area. When not in use, the inert gas system shall be made separate from the cargo system in the cargo area except for connections to the hold spaces or interbarrier spaces. 1.4.5 The arrangements shall be such that each space being inerted can be isolated and the necessary controls and relief valves, etc., shall be provided for controlling pressure in these spaces. 1.4.6 Where insulation spaces are continually supplied with an inert gas as part of a leak detection system, means shall be provided to monitor the quantity of gas being supplied to individual spaces. Guidance note: This applies to detection of leakage through the secondary barrier. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.4.7 For inert gas lines/nitrogen lines having permanent connection to the cargo system or fuel gas system, the inert gas supply line shall be fitted with two shutoff valves in series with a venting valve in between (double block and bleed valves) as given in [1.4.8]. In addition a closable non-return valve shall be installed between the double block and bleed arrangement and the fuel system. These valves shall be located outside non-hazardous spaces. 1.4.8 The two shut-off valves in series with a venting valve in between given in [1.4.7] shall be provided with:

.1

the operation of the valve is automatically executed. Signal(s) for opening/closing shall be taken from the process directly, e.g. inert gas flow or differentialpressure; and

.2

alarm for faulty operation of the valves is provided, e.g. the operation status of "blower stop" and "supply valve(s) open" is an alarm condition.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 144

Part 5 Chapter 7 Section 9

1.3 Environmental control of spaces surrounding type C independent tanks

2.1 General requirements 2.1.1 The equipment shall be capable of producing inert gas with an oxygen content at no time greater than 5% by volume, subject to the special requirements of Sec.17. A continuous-reading oxygen content meter shall be fitted to the inert gas supply from the equipment and shall be fitted with an alarm set at a maximum of 5% oxygen content by volume, subject to the requirements of Sec.17. Guidance note: Inert gas can be generated by a nitrogen generator system making nitrogen by forcing air through a membrane separation vessel or by an inert gas generator where suitable fuel is burned to make inert gas. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.2 An inert gas system shall have pressure controls and monitoring arrangements appropriate to the cargo containment system. 2.1.3 Spaces containing inert gas generation plants shall have no direct access to accommodation spaces, service spaces or control stations, but may be located in machinery spaces. Inert gas piping shall not pass through accommodation spaces, service spaces or control stations. 2.1.4 Combustion equipment for generating inert gas shall not be located within the cargo area. Special consideration may be given to the location of inert gas generating equipment using a catalytic combustion process. 2.1.5 Where fitted, a nitrogen receiver or buffer tank shall be installed in a dedicated compartment or in the separate compartment containing the air compressor and the generator, engine room, or be located in the cargo area. Where the nitrogen receiver or buffer tank is installed in an enclosed space, the access shall be arranged only from the open deck and the access door shall open outwards. Where a separate compartment is provided it shall be fitted with an independent mechanical extraction ventilation system, providing 6 air changes per hour. A low oxygen alarm shall be fitted. The compartment shall have no direct access to accommodation spaces, service spaces or control stations. Guidance note: Gas carriers built also to carry oil with flashpoint less than 60°C should comply with the inert gas requirements of SOLAS as for oil tankers, Ch.5 or for chemical tankers, Ch.6. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.6 Control and monitoring of inert gas generator is given in Sec.13 [13].

2.2 Nitrogen systems 2.2.1 The nitrogen generator shall be capable of delivering high purity nitrogen in the system and shall be fitted with automatic means to discharge off-spec gas to the atmosphere during start-up and abnormal operation. 2.2.2 A feed air treatment system shall be fitted to remove water, particles and traces of oil from the compressed air. 2.2.3 The oxygen-enriched air from the nitrogen generator and the nitrogen-product enriched gas from the protective devices of the nitrogen receiver shall be discharged to a safe location on the open deck.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 145

Part 5 Chapter 7 Section 9

2 Inert gas production on board

Oxygen-enriched air from the nitrogen generator - safe locations on the open deck are: — outside of hazardous area — not within 3 m of areas traversed by personnel — not within 6 m of air intakes for machinery (engines and boilers) and all ventilation inlets. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: Nitrogen-product enriched gas from the protective devices of the nitrogen receiver - safe locations on the open deck are: — not within 3 m of areas traversed by personnel — not within 6 m of air intakes for machinery (engines and boilers) and all ventilation inlets/outlets. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.4 In order to permit maintenance, means of isolation shall be fitted between the generator and the receiver. 2.2.5 Control and monitoring of nitrogen generator is given in Sec.13 [14].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 146

Part 5 Chapter 7 Section 9

Guidance note:

1 General 1.1 General 1.1.1 The requirements in this chapter are additional to those given in Pt.4 Ch.8. Relaxation from these rules may be accepted for ships built to carry only non-flammable products. 1.1.2 In order to facilitate the selection of appropriate electrical apparatus an the design of suitable electrical installations, hazardous areas are divided into zones 0, 1 and 2 according to the principles of the standards IEC 60079-10 and guidance and informative examples given in IEC 60092-502. Main features of the guidance are given in this section. Guidance note: With reference to IEC 60079-20, the following temperature class and equipment groups can be used: Product

Temperature class

Equipment group

methane (LNG)

T1

IIA

LPG (propane, butane)

T2

IIA

ethylene

T1

IIB

---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Definitions For the purpose of this section, unless expressly provided otherwise, the definitions below shall apply. 1.2.1 Hazardous area is an area in which an explosive gas atmosphere is or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of electrical apparatus. 1.2.2 Zone 0 hazardous area is an area in which an explosive gas atmosphere is present continuously or is present for long periods. 1.2.3 Zone 1 hazardous area is an area in which an explosive gas atmosphere is likely to occur in normal operation. 1.2.4 Zone 2 hazardous area is an area in which an explosive gas atmosphere is not likely to occur in normal operation and, if it does occur, is likely to do so infrequently and for a short period only. 1.2.5 Non-hazardous area is an area in which an explosive gas atmosphere is not expected to be present in quantities such as to require special precautions for the construction, installation and use of electrical apparatus.

1.3 General requirements 1.3.1 Electrical installations shall be such as to minimize the risk of fire and explosion from flammable products. 1.3.2 Electrical installations shall be in accordance to [1.1.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 147

Part 5 Chapter 7 Section 10

SECTION 10 ELECTRICAL INSTALLATIONS

1.3.4 Where electrical equipment is installed in hazardous areas as provided in [1.3.2] it shall be selected, installed and maintained in accordance with standards not inferior to those acceptable to the Society. Equipment for hazardous areas shall be evaluated and certified or listed by an accredited testing authority or notified body recognized by the Society. Automatic isolation of non-certified equipment on detection of a flammable gas shall not be accepted as an alternative to the use of certified equipment. 1.3.5 To facilitate the selection of appropriate electrical apparatus and the design of suitable electrical installations, hazardous areas are divided into zones as given in [1.2]. 1.3.6 Electrical generation and distribution systems, and associated control systems, shall be designed such that a single fault will not result in the loss of ability to maintain cargo tank pressures, as required by Sec.7 [8.1.1].1 and hull structure temperature, as required by Sec.4 [5.1.1].6, within normal operating limits. Failure modes and effects shall be analysed and documented to a standard not inferior to those acceptable to the Society. Guidance note: See IEC 60812, Edition 2.0 2006-01 Analysis techniques for system reliability – Procedure for failure mode and effects analysis (FMEA). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3.7 The lighting system in hazardous areas shall be divided between at least two branch circuits. All switches and protective devices shall interrupt all poles or phases and shall be located in a non-hazardous area. 1.3.8 Electrical depth sounding or log devices and impressed current cathodic protection system anodes or electrodes shall be housed in gastight enclosures. Guidance note: Gas tight enclosure is required only if the equipment is located in a hazardous area. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3.9 Submerged cargo pump motors and their supply cables may be fitted in cargo containment systems. Arrangements shall be made to automatically shut down the motors in the event of low-liquid level. This may be accomplished by sensing low pump discharge pressure, low motor current, or low liquid level. This shutdown shall be alarmed at the cargo control station. Cargo pump motors shall be capable of being isolated from their electrical supply during gas-freeing operations.

2 Area classification 2.1 General requirements 2.1.1 Area classification is a method of analysing and classifying the areas where explosive gas atmospheres may occur. The object of the classification shall allow the selection of electrical apparatus able to be operated safely in these areas. 2.1.2 Areas and spaces other than those classified in [2.2], shall be subject to special consideration. The principles of the IEC standards listed in [1.1.2], shall be applied. 2.1.3 Area classification of a space may be dependent of ventilation as specified in IEC 60092-502, Table 1. Requirements to such ventilation are given in Sec.12 [3.1.6] to Sec.12 [3.1.8].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 148

Part 5 Chapter 7 Section 10

1.3.3 Electrical equipment or wiring shall not be installed in hazardous areas unless essential for operational purposes or safety enhancement.

2.1.5 Ventilation ducts shall have the same area classification as the ventilated space.

2.2 Tankers carrying flammable liquefied gases 2.2.1 Hazardous areas zone 0 Following spaces are considered hazardous areas zone 0: interiors of cargo tanks, interbarrier spaces, hold spaces where the tank requires a secondary barrier, slop tanks, any pipework of pressure-relief or other venting systems for cargo and slop tanks, pipes and equipment containing the cargo or developing flammable gases or vapours. Guidance note: Instrumentation and electrical apparatus in contact with the gas or liquid should be of a type suitable for zone 0. Temperature sensors installed in thermo wells, and pressure sensors without additional separating chamber should be of intrinsically safe type Ex-ia. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.2 Hazardous areas zone 1 Hold spaces for tanks not requiring secondary barrier, void spaces adjacent to, above and below .1 integral cargo tanks.

.2 .3 .4

Cofferdams and permanent (for example, segregated) ballast tanks adjacent to cargo tanks.

.5

Spaces, other than cofferdam, adjacent to a cargo tank boundary or a secondary barrier (for example, trunks, passageways and hold).

.6

Areas on open deck, or semi- enclosed spaces on deck, within 3 m of any cargo tank outlet, gas or vapour outlet (see note), cargo manifold valve, cargo valve, cargo pipe flange, cargo pump-room ventilation outlets and cargo tank openings for pressure release provided to permit the flow of small volumes of gas or vapour mixtures caused by thermal variation.

Cargo compressor room arranged with ventilation according to Sec.12 [3.1.7]. Enclosed or semi-enclosed spaces, immediately above cargo tanks (for example, between decks) or having bulkheads above and in line with cargo tanks bulkheads, unless protected by a diagonal plate acceptable to the appropriate authority.

Guidance note: Such areas are, for example, all areas within 3 m of cargo tank hatches, sight ports, tank cleaning openings, ullage openings, sounding pipes, cargo vapour outlets. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

.7

Areas on open deck, or semi-enclosed spaces on open deck above and in the vicinity of any cargo gas outlet intended for the passage of liquefied gas or large volumes of vapour mixture during cargo loading and ballasting or during discharging, within a vertical cylinder of unlimited height and 6 m radius centred upon the centre of the outlet, and within a hemisphere of 6 m radius below the outlet.

.8

Areas on open deck, or semi-enclosed spaces on open deck, within 1.5 m of cargo pump room entrances, cargo pump room ventilation inlet, openings into cofferdams or other zone 1 spaces.

.9

Areas on the open deck within spillage coamings surrounding cargo manifold valves and 3 m beyond these, up to a height of 2.4 m above the deck.

.10

Areas where structures are obstructing the natural ventilation e.g. by semi-enclosed spaces, up to a height of 2.4 m above the deck and structure. This applies to: — areas in the cargo area on open deck (including also areas above ballast tanks within the cargo area), to the full breadth of the ship — 3 m fore and aft of the forward-most and after-most cargo tank bulkhead.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 149

Part 5 Chapter 7 Section 10

2.1.4 A space with opening to an adjacent hazardous area on open deck, may be made into a less hazardous or non-hazardous space, by means of overpressure. Requirements to such pressurisation are given in Sec.12 [3].

Compartments for cargo hoses. Enclosed or semi-enclosed spaces in which pipes containing cargoes are located.

2.2.3 Hazardous areas zone 2 Areas within 1.5 m surrounding open or semi-enclosed spaces of zone 1 as specified in [2.2.2], if not .1 otherwise specified in this standard.

.2 .3 .4

Spaces 4 m beyond the cylinder and 4 m beyond the sphere defined in [2.2.2].7.

.5

Areas on open deck over all cargo tanks (including all ballast tanks within the cargo tank area) where unrestricted natural ventilation is guaranteed and to the full breadth of the ship plus 3 m fore and aft of the forward-most and aft-most cargo tank bulkhead, up to a height of 2.4 m above the deck surrounding open or semi-enclosed spaces of zone 1.

.6

Spaces forward of the open deck areas to which reference is made in [2.2.2].10 and [2.2.3].5, below the level of the main deck, and having an opening on to the main deck or at a level less than 0.5 m above the main deck, unless:

Spaces forming an air-lock as defined in Sec.1 [3.1]. Areas on open deck extending to the coamings fitted to keep any spills on deck and away from the accommodation and service areas and 3 m beyond these up to a height of 2.4 m above deck.

— the entrances to such spaces do not face the cargo tank area and, together with all other openings to the spaces, including ventilating system inlets and exhausts, are situated at least 10 m horizontally from any cargo tank outlet or gas or vapour outlet, and — the spaces are mechanically ventilated.

2.3 Electrical installations in cargo area and adjacent to this area In addition to [1.3.2], installations as specified in [2.3] are accepted. 2.3.1 In zone 1: Impressed cathodic protection equipment is accepted provided the following is complied with: — such equipment shall be of gas-tight construction or be housed in a gas tight enclosure — cables shall be installed in steel pipes with gas-tight joints up to the upper deck — corrosion resistant pipes, providing adequate mechanical protection, shall be used in compartments which may be filled with seawater (e.g. permanent ballast tanks) — wall thickness of the pipes shall be as for overflow and sounding pipes through ballast or fuel tanks, in accordance with Pt.4 Ch.6. In zone 0: Submersible electrically driven pumps are accepted provided the following is complied with: — at least two independent means of shutting down automatically in the event of low liquid level, and prevention from being energised when not submerged — the supply circuit to the pumps shall be automatically disconnected and/or shall be prevented from being energised in the event of an abnormally low level of insulation resistance or high level of leakage current — the protective systems shall be arranged so that manual intervention is necessary for the reconnection of the circuit after disconnection after a short circuit, overload or earth-fault condition. 2.3.2 Additional requirements may apply for certain cargoes according to Sec.17 and Sec.19.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 150

Part 5 Chapter 7 Section 10

.11 .12

3.1 General requirements 3.1.1 Before the electrical installations in hazardous areas are put into service or considered ready for use, they shall be inspected and tested. All equipment, cables, etc. shall be verified to have been installed in accordance with installations procedures and guidelines issued by the manufacturer of the equipment, cables, etc., and that the installations have been carried out in accordance to Pt.4 Ch.8 Sec.11. 3.1.2 For spaces protected by pressurisation it shall be examined and tested that the purging can be effected. Purge time at minimum flow rate shall be documented. Required shutdowns and/or alarms upon ventilation overpressure falling below prescribed values shall be tested. For other spaces where area classification depends on mechanical ventilation it shall be tested that ventilation flow rate is sufficient, and that and required ventilation failure alarm operates correctly. 3.1.3 For equipment for which safety in hazardous areas depends upon correct operation of protective devices (for example overload protection relays) and/or operation of an alarm (for example loss of pressurisation for an Ex(p) control panel) it shall be verified that the devices have correct settings and/or correct operation of alarms. 3.1.4 Where interlocking and shutdown arrangements are required (such as for submerged cargo pumps), they shall be tested. 3.1.5 Intrinsically safe circuits shall be verified to ensure that the equipment and wiring are correctly installed. 3.1.6 Verification of the physical installation shall be documented by yard. The documentation shall be available for the Society's surveyor at the site.

4 Maintenance 4.1 General requirements 4.1.1 The maintenance manual referred to in Sec.1 [4], shall be in accordance with the recommendations in IEC 60079-17 and 60092-502 and shall contain necessary information on: — overview of classification of hazardous areas, with information about gas groups and temperature class — records sufficient to enable the certified safe equipment to be maintained in accordance with its type of protection (list and location of equipment, technical information, manufacturer's instructions, spares etc.) — inspection routines with information about detailing level and time intervals between the inspections, acceptance/rejection criteria — register of inspections, with information about date of inspections and name(s) of person(s) who carried out the inspection and maintenance work. 4.1.2 Updated documentation and maintenance manual, shall be kept onboard, with records of date and names of companies and persons who have carried out inspections and maintenance. Inspection and maintenance of installations shall be carried out only by experienced personnel whose training has included instruction on the various types of protection of apparatus and installation practices to be found on the vessel. Appropriate refresher training shall be given to such personnel on a regular basis.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 151

Part 5 Chapter 7 Section 10

3 Inspection and testing

1 Fire safety requirements 1.1 General requirements 1.1.1 Requirements for tankers in SOLAS chapter II-2 apply to ships, irrespective of tonnage, including ships of less than 500 gross tonnage with the following exceptions:

.1 .2

SOLAS Ch.II-2 regulation 4.5.1.6 and SOLAS Ch.II-2 regulation 4.5.10 do not apply

.3 .4

SOLAS Ch.II-2 regulation 10.5.6 shall apply to ships of 2000 gross tonnage and over

SOLAS Ch.II-2 regulation 10.2 as applicable to cargo ships, and SOLAS Ch.II-2 regulation 10.4 and SOLAS Ch.II-2 regulation 10.5 shall apply as they would apply to tankers of 2000 gross tonnage and over the following regulations of SOLAS chapter II-2 related to tankers do not apply and are replaced by requirements of this chapter as detailed below: Table 1 SOLAS regulation

.5

Replaced by

10.10

[6]

4.5.1.1 and 4.5.1.2

Sec.3

4.5.5

Relevant sections

10.8

[3] and [4]

10.9

[5]

10.2

[2.1]

SOLAS Ch.II-2 regulation 13.3.4 and SOLAS Ch.II-2 regulation 13.4.3 shall apply to ships of 500 gross tonnage and over.

1.1.2 All sources of ignition shall be excluded from spaces where flammable vapour may be present, except as otherwise provided in Sec.10 and Sec.16. 1.1.3 The provisions of this section shall apply in conjunction with Sec.3. 1.1.4 For the purposes of fire fighting, any weather deck areas above cofferdams, ballast or void spaces at the after end of the aftermost hold space or at the forward end of the forwardmost hold space shall be included in the cargo area.

2 Fire mains and hydrants 2.1 General requirements 2.1.1 All ships, irrespective of size, carrying products that are subject to the chapter shall comply with the requirements of regulation ll-2/10.2 of the SOLAS convention, except that the required fire pump capacity and fire main and water service pipe diameter shall not be limited by the provisions of regulations ll-2/10.2.2.4.1 and ll-2/10.2.1.3, when a fire pump is used to supply the water spray system, as

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 152

Part 5 Chapter 7 Section 11

SECTION 11 FIRE PROTECTION AND EXTINCTION

2.1.2 The arrangements shall be such that at least two jets of water can reach any part of the deck in the cargo area and those portions of the cargo containment system and tank covers that are above the deck. The necessary number of fire hydrants shall be located to satisfy the above arrangements and to comply with the requirements of regulations ll-2/10.2.1.5.1 and ll-2/10.2.3.3 of the SOLAS convention, with hose lengths as specified in regulation ll-2/10.2.3.1.1 of the SOLAS convention. In addition, the requirements of regulation ll-2/10.2.1.6 of the SOLAS convention, shall be met at a pressure of at least 0.5 MPa. 2.1.3 Stop valves shall be fitted in any crossover provided and in the fire main or mains in a protected location, before entering the cargo area and at intervals ensuring isolation of any damaged single section of the fire main, so that [2.1.2] can be complied with using not more than two lengths of hoses from the nearest fire hydrant. The water supply to the fire main serving the cargo area shall be a ring main supplied by the main fire pumps or a single main supplied by fire pumps positioned fore and aft of the cargo area, one of which shall be independently driven. 2.1.4 All nozzles shall be of an approved dual purpose type, i.e. spray/jet type, incorporating a shutoff. 2.1.5 After installation, the pipes, valves, fittings and assembled system shall be subject to a tightness and function test.

3 Water spray system 3.1 General requirements 3.1.1 On ships carrying flammable or toxic products, or both, a water application system, which may be based on water spray nozzles, for cooling, fire prevention and crew protection shall be installed to cover:

.1

Exposed cargo tank domes, any exposed parts of cargo tanks and any part of cargo tank covers that may be exposed to heat from fires in adjacent equipment containing cargo such as exposed booster pumps/heaters/re- gasification or re-liquefaction plants, hereafter addressed as gas process units, positioned on weather decks.

.2 .3 .4

Exposed on-deck storage vessels for flammable or toxic products.

.5

All exposed emergency shut-down (ESD) valves in the cargo liquid and vapour pipes, including the master valve for supply to gas consumers.

.6

Exposed boundaries facing the cargo area, such as bulkheads of superstructures and deckhouses normally manned, cargo machinery spaces, store-rooms containing high fire risk items and cargo control rooms. Exposed horizontal boundaries of these areas do not require protection unless detachable cargo piping connections are arranged above or below. Boundaries of unmanned forecastle structures not containing high fire-risk items or equipment do not require water-spray protection.

.7

Exposed lifeboats, life rafts and muster stations facing the cargo area, regardless of distance to cargo area, and:

.8

Any semi-enclosed cargo machinery spaces and semi-enclosed cargo motor room.

Gas process units, positioned on deck. Cargo liquid and vapour discharge and loading connections, including the presentation flange and the area where their control valves are situated, which shall be at least equal to the area of the drip trays provided.

Ships intended for operation as listed in Sec.1 [2.1.5], shall be subject to special consideration and covered by Pt.6 Ch.4 Sec.8.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 153

Part 5 Chapter 7 Section 11

permitted by [3.1.3]. The capacity of this fire pump shall be such that these areas can be protected when simultaneously supplying two jets of water from fire hoses with 19 mm nozzles at a pressure of at least 0.5 MPa gauge.

3.1.3 On vertical surfaces, spacing of nozzles protecting lower areas may take account of anticipated rundown from higher areas. Stop valves shall be fitted in the spray water application main supply line(s), at intervals not exceeding 40 m, for the purpose of isolating damaged sections. Alternatively, the system may be divided into two or more sections that may be operated independently, provided the necessary controls are located together in a readily accessible position outside of the cargo area. A section protecting any area included in [3.1.1].1 and [3.1.1].2 shall cover at least the entire athwartship tank grouping in that area. Any gas process unit(s) included in [3.1.1].3 may be served by an independent section. 3.1.4 The capacity of the water application pumps shall be capable of simultaneous protection of the greatest of the following:

.1 .2

any two complete athwartship tank groupings, including any gas process units within these areas; or for ships intended for operation as listed in Sec.1 [2.1.5], necessary protection subject to special consideration under [3.1.1] of any added fire hazard and the adjacent athwartship tank grouping are covered in Pt.6 Ch.4 Sec.8.

In addition to surfaces specified in [3.1.1].4 to [3.1.1].8. Alternatively, the main fire pumps may be used for this service, provided that their total capacity is increased by the amount needed for the water-spray application system. In either case a connection, through a stop valve, shall be made between the fire main and water-spray application system main supply line outside of the cargo area. 3.1.5 The boundaries of superstructures and deckhouses normally manned, lifeboats, life-rafts and muster areas facing the cargo area, shall also be capable of being served by one of the fire pumps or the emergency fire pump, if a fire in one compartment could disable both fire pumps. 3.1.6 Water pumps normally used for other services may be arranged to supply the water spray application system main supply line. 3.1.7 All pipes, valves, nozzles and other fittings in the water application systems shall be resistant to corrosion by seawater. Piping, fittings and related components within the cargo area (except gaskets) shall be designed to withstand 925°C. The water application system shall be arranged with in-line filters to prevent blockage of pipes and nozzles. In addition, means shall be provided to back flush the system with fresh water. Guidance note: Water spray pipes should be provided with drain holes or valves at the lowest points. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: The sentence "In addition, means shall be provided to back-flush the system with fresh water", should be understood to mean that arrangements should be provided so that the water-spray system as a whole (i.e. piping, nozzles and in-line filters) can be flushed or back-flushed, as appropriate, with fresh water to prevent the blockage of pipes, nozzles and filters. Reference is made to MSC.1/Circ.1559 ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.8 Remote starting of pumps supplying the water application system and remote operation of any normally closed valves in the system shall be arranged in suitable locations outside the cargo area, adjacent to the accommodation spaces and readily accessible and operable in the event of fire in the protected areas.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 154

Part 5 Chapter 7 Section 11

3.1.2 The system shall be capable of covering all areas mentioned in [3.1.1] with a uniformly distributed 2 2 water application rate of at least 10 ℓ/m /minute for the largest projected horizontal surfaces and 4 ℓ/m / minute for vertical surfaces. For structures having no clearly defined horizontal or vertical surface, the 2 capacity of the water application shall not be less than the projected horizontal surface multiplied by 10 ℓ/m / minute.

4 Dry chemical powder fire-extinguishing systems 4.1 General requirements 4.1.1 Ships intended for carriage of flammable products shall be fitted with fixed dry chemical powder fire-extinguishing systems, approved by the Society based on the guidelines for the approval of fixed dry chemical powder fire-extinguishing systems for the protection of ships carrying liquefied gases in bulk (MSC. 1/Circ. 1315), for the purpose of firefighting on the deck in the cargo area, including any cargo liquid and vapour discharge and loading connections on deck and bow or stern cargo handling areas, as applicable. 4.1.2 The system shall be capable of delivering powder from at least two hand hose lines, or a combination of monitor/hand hose lines, to any part of the exposed cargo liquid and vapour piping, load/unload connection and exposed gas process units. 4.1.3 The dry chemical powder fire-extinguishing system shall be designed with not less than two independent units. Any part required to be protected by [4.1.2] shall be capable of being reached from not less than two independent units with associated controls, pressurizing medium fixed piping, monitors or 3 hand hose lines. For ships with a cargo capacity of less than 1000 m , only one such unit is required fitted. A monitor shall be arranged to protect any load/unload connection area and be capable of actuation and discharge both locally and remotely. The monitor is not required to be remotely aimed if it can deliver the necessary powder to all required areas of coverage from a single position. One hose line shall be provided at both port- and starboard side at the end of the cargo area facing the accommodation and readily available from the accommodation. 4.1.4 The capacity of a monitor shall be not less than 10 kg/s. Hand hose lines shall be non-kinkable and be fitted with a nozzle capable of on/off operation and discharge at a rate not less than 3.5 kg/s. The maximum discharge rate shall allow operation by one man. The length of a hand hose line shall not exceed 33 m. Where fixed piping is provided between the powder container and a hand hose line or monitor, the length of piping shall not exceed that length which is capable of maintaining the powder in a fluidized state during sustained or intermittent use, and which can be purged of powder when the system is shut down. Hand hose lines and nozzles shall be of weather-resistant construction or stored in weather resistant housing or covers and be readily accessible. 4.1.5 Hand hose lines shall be considered to have a maximum effective distance of coverage equal to the length of hose. Special consideration shall be given where areas to be protected are substantially higher than the monitor or hand hose reel locations. 4.1.6 Ships fitted with bow, stern load/unload connections shall be provided with independent dry powder unit protecting the cargo liquid and vapour piping, aft or forward of the cargo area, by hose lines and a monitor covering the bow, stern load/unload complying with the requirements of [4.1.1] to [4.1.5]. 4.1.7 Ships intended for operation as listed in Sec.1 [2.1.5] are covered in Pt.6 Ch.4 and for dedicated storage vessels are subject to special considerations. 4.1.8 After installation, the pipes, valves, fittings and assembled systems shall be subjected to a tightness test and functional testing of the remote and local release stations. The initial testing shall also include a discharge of sufficient amounts of dry chemical powder to verify that the system is in proper working order. All distribution piping shall be blown through with dry air to ensure that the piping is free of obstructions.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 155

Part 5 Chapter 7 Section 11

3.1.9 After installation, the pipes, valves, fittings and assembled system shall be subject to a tightness and function test.

At least one dry chemical powder hose and one monitor shall be tested for each ship. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5 Enclosed spaces containing cargo handling equipment 5.1 General requirements 5.1.1 Enclosed spaces meeting the criteria of cargo machinery spaces in Sec.1 [3.1], and the cargo motor room within the cargo area of any ship, shall be provided with a fixed fire-extinguishing system complying with the provisions of the FSS code and taking into account the necessary concentrations/application rate required for extinguishing gas fires. 5.1.2 Enclosed spaces meeting the criteria of cargo machinery spaces in Sec.3 [3], within the cargo area of ships that are dedicated to the carriage of a restricted number of cargoes, shall be protected by an appropriate fire-extinguishing system for the cargo carried. 5.1.3 Turret compartments of any ship shall be protected by internal water spray, with an application rate 2 of not less than 10 ℓ/m /minute of the largest projected horizontal surface. If the pressure of the gas flow 2 through the turret exceeds 4 MPa, the application rate shall be increased to 20 ℓ/m /minute. The system shall be designed to protect all internal surfaces.

6 Firefighters' outfits 6.1 General requirements 6.1.1 Every ship carrying flammable products shall carry firefighter's outfits complying with the requirements of regulation ll-2/10.10 of the SOLAS convention, as follows: Table 2 Total capacity 3

5000 m and below above 5000 m

3

Number of outfits 4 5

6.1.2 Additional requirements for safety equipment are given in Sec.14. 6.1.3 Any breathing apparatus required as part of a firefighter’s outfit shall be a self-contained compressed air-operated breathing apparatus having a capacity of at least 1200ℓ of free air.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 156

Part 5 Chapter 7 Section 11

Guidance note:

1 Spaces required to be entered during normal handling operations 1.1 General requirements 1.1.1 Electric motor rooms, cargo compressor and pump rooms, spaces containing cargo handling equipment and other enclosed spaces where cargo vapours may accumulate, shall be fitted with fixed artificial ventilation systems capable of being controlled from outside such spaces. The ventilation shall be run continuously to prevent the accumulation of toxic and/or flammable vapours, with a means of monitoring acceptable to the Society to be provided. A warning notice requiring the use of such ventilation prior to entering, shall be placed outside the compartment. 1.1.2 Artificial ventilation inlets and outlets shall be arranged to ensure sufficient air movement through the space to avoid accumulation of flammable, toxic or asphyxiant vapours, and to ensure a safe working environment. 1.1.3 The ventilation system shall have a capacity of not less than 30 changes of air per hour, based upon the total volume of the space. As an exception, non-hazardous cargo control rooms may have eight changes of air per hour. 1.1.4 Where a space has an opening into an adjacent more hazardous space or area, it shall be maintained at an over-pressure. It may be made into a less hazardous space or non-hazardous space by over-pressure protection. 1.1.5 Ventilation ducts, air intakes and exhaust outlets serving artificial ventilation systems shall be positioned in as given in [3]. 1.1.6 Ventilation ducts serving hazardous areas shall not be led through accommodation, service and machinery spaces or control stations or other non-hazardous spaces, except as allowed in Sec.16. 1.1.7 Electric motors driving fans shall be placed outside the ventilation ducts that may contain flammable vapours. Ventilation fans shall not produce a source of ignition in either the ventilated space or the ventilation system associated with the space. For hazardous areas, ventilation fans and ducts, adjacent to the fans, shall be of non-sparking construction, as defined below:

.1

impellers or housing of non-metallic construction, with due regard being paid to the elimination of static electricity

.2 .3 .4 .5

impellers and housing of non-ferrous materials impellers and housing of austenitic stainless steel ferrous impellers and housing with not less than 13 mm design tip clearance impellers of aluminium alloys or magnesium alloys and a ferrous (including austenitic stainless steel) housing on which a ring of suitable thickness of non-ferrous materials is fitted in way of the impeller, due regard being paid to static electricity and corrosion between ring and housing.

Any combination of an aluminium or magnesium alloy fixed or rotating component and a ferrous fixed or rotating component, regardless of tip clearance, is considered a sparking hazard and shall not be used in these places. 1.1.8 Where fans are required by this section, full required ventilation capacity for each space shall be available after failure of any single fan or spare parts shall be provided comprising; a motor, starter spares and complete rotating element, including bearings of each type.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 157

Part 5 Chapter 7 Section 12

SECTION 12 ARTIFICIAL VENTILATION IN CARGO AREA

1.1.10 Where spaces are protected by pressurization the ventilation shall be designed and installed as given in [3]. 1.1.11 Starters for fans for ventilation of non-hazardous spaces in cargo area, shall be located outside the cargo area or on open deck. If electric motors are installed in such rooms, the ventilation capacity shall be great enough to prevent the temperature limits specified in Pt.4 Ch.8, from being exceeded, taking into account the heat generated by the electric motors. Guidance note: The principles of ventilation should the standard International Electrotechnical Commission, in particular, to publication IEC 60092-502:1999. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.12 The installation of the ventilation units shall be such as to ensure the safe bonding to the hull of the units themselves. Resistance between any point on the surface of the unit and the hull shall not be greater than 1MΩ.

2 Spaces not normally entered 2.1 General requirements 2.1.1 Enclosed spaces where cargo vapours may accumulate shall be capable of being ventilated to ensure a safe environment when entry into them is necessary. This shall be capable of being achieved without the need for prior entry. 2.1.2 For permanent installations, the capacity of 8 air changes per hour shall be provided and for portable systems, the capacity of 16 air changes per hour. Guidance note: For hold spaces containing independent tanks a lower capacity may be considered on a case by case basis, provided it can be demonstrated that the space concerned can be satisfactorily gas-freed in less than 5 hours. For inerted spaces an increase of the oxygen content from 0% to 20% in all locations of the space within 5 hours would be acceptable ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.3 Fans or blowers shall be clear of personnel access openings, and shall comply with [1.1.7].

3 Ventilation arrangement and capacity requirements 3.1 General requirements 3.1.1 Any ducting used for the ventilation of hazardous spaces shall be separate from that used for the ventilation of non-hazardous spaces. Ventilation systems within the cargo area shall be independent of other ventilation systems. 3.1.2 Air inlets for hazardous enclosed spaces shall be taken from areas which, in the absence of the considered inlet, would be non-hazardous. Air inlets for non-hazardous enclosed spaces shall be taken from non-hazardous areas at least 1.5 m away from the boundaries of any hazardous area.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 158

Part 5 Chapter 7 Section 12

1.1.9 Protection screens of not more than 13 mm square mesh shall be fitted to outside openings of ventilation ducts.

3.1.3 Air outlets from non-hazardous spaces shall be located outside hazardous areas. 3.1.4 Air outlets from hazardous enclosed spaces shall be located in an open area which, in the absence of the considered outlet, would be of the same or lesser hazard than the ventilated space. 3.1.5 The required capacity of the ventilation plant is normally based on the total volume of the room. An increase in required ventilation capacity may be necessary for rooms having a complicated form. 3.1.6 The exhaust outlets for hazardous space shall discharge upwards. 3.1.7 Ventilation systems for pump and compressor rooms shall be in operation when pumps or compressors are working. Pumps and compressors shall not be started before the ventilation system in the electric motor room has been in operation for 15 minutes. Warning notices to this effect shall be placed in an easily visible position near the control stand. 3.1.8 When the space is dependent on ventilation for its area classification, the following requirements apply: 1) 2) 3)

During initial start-up, and after loss of ventilation, the space shall be purged (at least 5 air changes), before connecting electrical installations which are not certified for the area classification in absence of ventilation. Operation of the ventilation shall be monitored. In the event of failure of ventilation, the following requirements apply: — an audible and visual alarm shall be given at a manned location — immediate action shall be taken to restore ventilation — electrical installations shall be disconnected if ventilation cannot be restored for an extended period. The disconnection shall be made outside the hazardous areas, and be protected against unauthorised re-connection, e.g. by lockable switches. Guidance note: Intrinsically safe equipment suitable for zone 0, is not required to be switched off. Certified flameproof lighting, may have a separate switch-off circuit. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.9 Air lock spaces shall be mechanically ventilated at an overpressure relative to the adjacent open deck hazardous area. 3.1.10 Other spaces situated on or above cargo deck level (e.g. cargo handling gear lockers) may be accepted with natural ventilation only.

3.2 Non-hazardous spaces 3.2.1 Spaces with opening to a hazardous area, shall be arranged with an air-lock, and be maintained at overpressure, relative to the external hazardous area.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 159

Part 5 Chapter 7 Section 12

Where the inlet duct passes through a more hazardous space, the duct shall have over-pressure relative to this space, unless mechanical integrity and gas-tightness of the duct will ensure that gases will not leak into it.

1)

During initial start-up or after loss of overpressure ventilation, it is required before energising any electrical installations not certified safe for the space in the absence of pressurisation, to: — proceed with purging (at least 5 air changes) or confirm by measurements that the space is nonhazardous — pressurise the space.

2)

Operation of the overpressure ventilation shall be monitored.

3)

In the event of failure of the overpressure ventilation: — an audible and visual alarm shall be given at a manned location — if overpressure cannot be immediately restored, automatic or programmed disconnection of electrical installations is required according to IEC 60092-502, Table 5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 160

Part 5 Chapter 7 Section 12

The overpressure ventilation shall be arranged according to the following requirements:

1 General 1.1 General requirements 1.1.1 Each cargo tank shall be provided with a means for indicating level, pressure and temperature of the cargo. Pressure gauges and temperature indicating devices shall be installed in the liquid and vapour piping systems, in cargo refrigeration and thermal oxidation installation (GCU). 1.1.2 If loading and unloading of the ship is performed by means of remotely controlled valves and pumps, all controls and indicators associated with a given cargo tank shall be concentrated in one control position. 1.1.3 Instruments shall be tested to ensure reliability under the working conditions and re-calibrated at regular intervals. Test procedures for instruments and the intervals between re-calibration shall be in accordance with manufacturer's recommendations and shall be submitted for review by the Society. 1.1.4 For instrumentation and automation, including computer based control and monitoring, the requirements in this chapter are additional to those given in Pt.4 Ch.9. 1.1.5 Remote reading systems for cargo temperature and pressure shall not allow the cargo or vapour to reach gas-safe spaces. Direct pipe connections will not be accepted.

2 Level indicators for cargo tanks 2.1 General requirements 2.1.1 Each cargo tank shall be fitted with liquid level gauging device(s), arranged to ensure a level reading is always obtainable whenever the cargo tank is operational. The device(s) shall be designed to operate throughout the design pressure range of the cargo tank and at temperatures within the cargo operating temperature range. 2.1.2 Where only one liquid level gauge is fitted, it shall be arranged so that it can be maintained in an operational condition without the need to empty or gas-free the tank. 2.1.3 Cargo tank liquid level gauges may be of the following types, subject to special requirements for particular cargoes shown in column g in Sec.19 Table 2:

.1

Indirect devices, which determine the amount of cargo by means such as weighing or in-line flow metering.

.2

Closed devices, which do not penetrate the cargo tank, such as devices using radio-isotopes or ultrasonic devices.

.3

Closed devices, which penetrate the cargo tank, but which form part of a closed system and keep the cargo from being released, such as float type systems, electronic probes, magnetic probes and bubble tube indicators. If a closed gauging device is not mounted directly onto the tank, it shall be provided with a shutoff valve located as close as possible to the tank, and:

.4

Restricted devices, which penetrate the tank and when in use permit a small quantity of cargo vapour or liquid to escape to the atmosphere, such as fixed tube and slip tube gauges. When not in use, the devices shall be kept completely closed. The design and installation shall ensure that no dangerous escape of cargo can take place when opening the device. Such gauging devices shall be so designed

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 161

Part 5 Chapter 7 Section 13

SECTION 13 INSTRUMENTATION AND AUTOMATION

3 Overflow control 3.1 General requirements 3.1.1 Except as provided in [3.1.4] each cargo tank shall be fitted with a high liquid level alarm operating independently of other liquid level indicators and giving an audible and visual warning when activated. 3.1.2 An additional sensor operating independently of the high liquid level alarm shall automatically actuate a shutoff valve in a manner that will both avoid excessive liquid pressure in the loading line and prevent the tank from becoming liquid full. Guidance note: The high liquid level alarm [3.1.1] and the additional sensor [3.1.2] shall be implemented in systems that are complete independent of each other. One of these may be combined with level gauging system [2.1.1]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.3 The emergency shutdown valve referred to in Sec.5 [5] and Sec.18 [2] may be used for this purpose. If another valve is used for this purpose, the same information as referred to in Sec.18 [2.2.3] shall be available on board. During loading, whenever the use of these valves may possibly create a potential excess pressure surge in the loading system, alternative arrangements such as limiting the loading rate shall be used. 3.1.4 A high liquid level alarm and automatic shut-off of cargo tank filling need not be required when the cargo tank:

.1 .2

3

is a pressure tank with a volume not more than 200 m , or is designed to withstand the maximum possible pressure during the loading operation and such pressure is below that of the set pressure of the cargo tank relief valve.

3.1.5 The position of the sensors in the tank shall be capable of being verified before commissioning. At the first occasion of full loading after delivery and after each dry-docking when cargo tank has been in gas free condition, testing of high level alarms shall be conducted by raising the cargo liquid level in the cargo tank to the alarm point. Guidance note: The expression "each dry docking" is considered to refer to the survey of the outside of the ship's bottom required for the renewal of the Cargo Ship Safety Construction Certificate and/or the Cargo Ship Safety Certificate. See IACS GC18. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.6 All elements of the level alarms, including the electrical circuit and the sensor(s), of the high and overfill alarms, shall be capable of being functionally tested. Systems shall be tested prior to cargo operation. 3.1.7 Where arrangements are provided for overriding the overflow control system, they shall be such that inadvertent operation is prevented. When this override is operated, continuous visual indication shall be given at the relevant control station(s) and the navigating bridge. 3.1.8 When pumps situated in different tanks discharge into a common header, unintended stop of a pump shall be alarmed at the centralized cargo control position.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 162

Part 5 Chapter 7 Section 13

that the maximum opening does not exceed 1.5 mm diameter or equivalent area, unless the device is provided with an excess flow valve.

4.1 General requirements 4.1.1 The vapour space of each cargo tank shall be provided with a direct reading gauge. Additionally, an indirect indication shall be provided at the control position required by [1.1.2]. Maximum and minimum allowable pressures shall be clearly indicated. 4.1.2 A high-pressure alarm and, if vacuum protection is required, a low-pressure alarm shall be provided on the navigating bridge and at the control position required by [1.1.2]. Alarms shall be activated before the set pressures are reached. 4.1.3 For cargo tanks fitted with PRVs, which can be set at more than one set pressure in accordance with Sec.8 [2.2.4], high-pressure alarms shall be provided for each set pressure. 4.1.4 Each cargo-pump discharge line and each liquid and vapour cargo manifold shall be provided with at least one pressure indicator. 4.1.5 Local-reading manifold pressure indication shall be provided to indicate the pressure between ship's manifold valves and hose connections to the shore. 4.1.6 Hold spaces and interbarrier spaces without open connection to the atmosphere shall be provided with pressure indication. 4.1.7 All pressure indications provided shall be capable of indicating throughout the operating pressure range.

5 Temperature indicating devices 5.1 General requirements 5.1.1 Each cargo tank shall be provided with at least two devices for indicating cargo temperatures, one placed at the bottom of the cargo tank and the second near the top of the tank, below the highest allowable liquid level. The lowest temperature for which the cargo tank has been approved by the Society shall be clearly indicated, by means of a sign on or near the temperature indicating devices. 5.1.2 The temperature indicating devices shall be capable of providing temperature indication across the expected cargo operating temperature range of the cargo tanks. 5.1.3 Where thermowells are fitted they shall be designed to minimize failure due to fatigue in normal service.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 163

Part 5 Chapter 7 Section 13

4 Pressure monitoring

6.1 General requirements 6.1.1 Gas detection equipment shall be installed to monitor the integrity of the cargo containment, cargo handling and ancillary systems in accordance with this section. 6.1.2 A permanently installed system of gas detection and audible and visual alarms shall be fitted in:

.1

all enclosed cargo and cargo machinery spaces (including turrets compartments) containing gas piping, gas equipment or gas consumers

.2

other enclosed or semi-enclosed spaces where cargo vapours may accumulate including interbarrier spaces and hold spaces for independent tanks other than type C

.3 .4 .5 .6 .7 .8

airlocks the spaces in gas fired internal combustion engines, referred to in Sec.16 [7.3.3] ventilation hoods and gas ducts required by Sec.16 cooling/heating circuits, including degassing tank if fitted, as required by Sec.7 [8.1.1] inert gas generator supply headers, and motor rooms for cargo handling machinery. Guidance note: Gas detection, with regard to [6.1.2] 7), should be fitted for the pipe section between the inert gas generator and devices preventing back flow. ow. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.1.3 Gas detection equipment shall be designed, installed and tested. Such equipment shall be suitable for the cargoes to be carried in accordance with column f in Sec.19 Table 2. 6.1.4 Where indicated by an A in column f of Sec.19 Table 2 ships certified for carriage of non-flammable products, oxygen deficiency monitoring shall be fitted in cargo machinery spaces and hold spaces for independent tanks other than type C tanks. Furthermore, oxygen deficiency monitoring equipment shall be installed in enclosed or semi-enclosed spaces containing equipment that may cause an oxygen-deficient environment such as nitrogen generators, inert gas generators or nitrogen cycle refrigerant systems. 6.1.5 In the case of products that are toxic or both toxic and flammable, except when column h in Sec.19 Table 2 refers to Sec.17 [1.4.3], portable equipment can be used for the detection of toxic products as an alternative to a permanently installed system. This equipment shall be used prior to personnel entering the spaces listed in [6.1.2] and at 30-minute intervals while the personnel remain in the space. 6.1.6 In the case of toxic gases, hold spaces and interbarrier spaces shall be provided with a permanently installed piping system for obtaining gas samples from the spaces. Gas from these spaces shall be sampled and analysed from each sampling head location. 6.1.7 Permanently installed gas detection shall be of the continuous detection type, capable of immediate response. Where such equipment is not used to activate safety shutdown functions required by [6.1.9] and Sec.16, the sampling type detection may be accepted. 6.1.8 When sampling type gas detection equipment is used, the following requirements shall be met:

.1

the gas detection equipment shall be capable of sampling and analysing for each sampling head location sequentially at intervals not exceeding 30 minutes

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 164

Part 5 Chapter 7 Section 13

6 Gas detection

individual sampling lines from sampling heads to the detection equipment shall be fitted, and pipe runs from sampling heads shall not be led through non-hazardous spaces except as permitted by [6.1.9].

6.1.9 The gas detection equipment may be located in a non-hazardous space, provided that the detection equipment such as sample piping, sample pumps, solenoids and analysing units are located in a fully enclosed steel cabinet with the door sealed by a gasket. The atmosphere within the enclosure shall be continuously monitored. At gas concentrations above 30% lower flammable limit (LFL) inside the enclosure, the gas detection equipment shall be automatically shut down. 6.1.10 Where the enclosure cannot be arranged directly on the forward bulkhead, sample pipes shall be of steel or equivalent material and be routed on their shortest way. Detachable connections, except for the connection points for isolating valves required in [6.1.11] and analysing units, are not permitted. 6.1.11 When gas sampling equipment is located in non-hazardous space, a flame arrester and a manual isolating valve shall be fitted in each of the gas sampling lines. The isolating valve shall be fitted on the nonhazardous side. Bulkhead penetrations of sample pipes between hazardous and non-hazardous areas shall maintain the integrity of the division penetrated. The exhaust gas shall be discharged to the open air in a safe location. 6.1.12 In every installation, the number and the positions of detection heads shall be determined with due regard to the size and layout of the compartment, the compositions and densities of the products intended to be carried and the dilution from compartment purging or ventilation and stagnant areas. 6.1.13 Any alarms status within a gas detection system required by this section shall initiate an audible and visible alarm:

.1 .2 .3

on the navigation bridge at the relevant control station(s) where continuous monitoring of the gas levels is recorded, and at the gas detector readout location.

6.1.14 In the case of flammable products, the gas detection equipment provided for hold spaces and interbarrier spaces that are required to be inerted, shall be capable of measuring gas concentrations of 0% to 100% by volume. 6.1.15 Alarms shall be activated when the vapour concentration by volume reaches the equivalent of 30% of the LFL in air. 6.1.16 For membrane containment systems, the primary and secondary insulation spaces shall be able to be inerted and their gas content analysed individually. The alarm in the secondary insulation space shall be set in accordance with [6.1.15] that in the primary space is set at a value approved by the Society. 6.1.17 For other spaces described by [6.1.2], alarms shall be activated when the vapour concentration reaches 30% LFL. Safety functions required by Sec.16 shall be activated before the vapour concentration reaches 60% LFL. The crankcases of internal combustion engines that can run on gas shall be arranged to alarm before 100% LFL. 6.1.18 Gas detection equipment shall be designed so that it may readily be tested. Testing and calibration shall be carried out at regular intervals. Suitable equipment for this purpose shall be carried on board and be used in accordance with the manufacturer's recommendations. Permanent connections for such test equipment shall be fitted. 6.1.19 Every ship shall be provided with at least two sets of portable gas detection equipment that meet the requirement of [6.1.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 165

Part 5 Chapter 7 Section 13

.2 .3

7 Additional requirements for containment systems requiring a secondary barrier 7.1 Integrity of barriers 7.1.1 Where a secondary barrier is required, permanently installed instrumentation shall be provided to detect when the primary barrier fails to be liquid-tight at any location or when liquid cargo is in contact with the secondary barrier at any location. This instrumentation shall consist of appropriate gas detecting devices according to [6]. However, it is not required that the instrumentation shall be capable of locating the area where liquid cargo leaks through the primary barrier or where liquid cargo is in contact with the secondary barrier.

7.2 Temperature indication devices 7.2.1 The number and position of temperature indicating devices shall be appropriate to the design of the containment system and cargo operation requirements. 7.2.2 When cargo is carried in a cargo containment system with a secondary barrier, at a temperature lower than -55°C, temperature indicating devices shall be provided within the insulation or on the hull structure adjacent to cargo containment systems. The devices shall give readings at regular intervals and, where applicable, alarm of temperatures approaching the lowest for which the hull steel is suitable. 7.2.3 If cargo shall be carried at temperatures lower than -55°C, the cargo tank boundaries, if appropriate for the design of the cargo containment system, shall be fitted with a sufficient number of temperature indicating devices to verify that unsatisfactory temperature gradients do not occur. 7.2.4 For the purposes of design verification and determining the effectiveness of the initial cooldown procedure on a single or series of similar ships, one tank shall be fitted with devices in excess of those required in [7.2.1]. These devices may be temporary or permanent and only need to be fitted to the first vessel, when a series of similar ships is built.

8 Automation systems 8.1 General requirements 8.1.1 The requirements of this section shall apply where automation systems are used to provide instrumented control, monitoring/alarm or safety functions required by this chapter. Guidance note: The below requirements in this section are additional to those given in Pt.4 Ch.9. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

8.1.2 Automation systems shall be designed, installed and tested. 8.1.3 Hardware shall be capable of being demonstrated to be suitable for use in the marine environment by type approval or other means. 8.1.4 Software shall be designed and documented for ease of use, including testing, operation and maintenance.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 166

Part 5 Chapter 7 Section 13

6.1.20 A suitable instrument for the measurement of oxygen levels in inert atmospheres shall be provided.

8.1.6 Automation systems shall be arranged such that a hardware failure or an error by the operator does not lead to an unsafe condition. Adequate safeguards against incorrect operation shall be provided. 8.1.7 Appropriate segregation shall be maintained between control, monitoring/alarm and safety functions to limit the effect of single failures. This shall be taken to include all parts of the automation systems that are required to provide specified functions, including connected devices and power supplies. 8.1.8 Automation systems shall be arranged such that the software configuration and parameters are protected against unauthorized or unintended change. 8.1.9 A management of change process shall be applied to safeguard against unexpected consequences of modification. Records of configuration changes and approvals shall be maintained on board. 8.1.10 Processes for the development and maintenance of integrated systems shall be in accordance with programme accepted by class. These processes shall include appropriate risk identification and management. Guidance note: See ISO/IEC 15288:2008. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9 System integration 9.1 General requirements 9.1.1 Essential safety functions shall be designed such that risks of harm to personnel or damage to the installation or the environment are reduced to a level acceptable to the Society, both in normal operation and under fault conditions. Functions shall be designed to fail safe. Roles and responsibilities for integration of systems shall be clearly defined and agreed by relevant parties. Guidance note: Essential safety functions in this context are defined as a safety function required by this rule chapter, i.e. a system that initiate an action to prevent escalation of potential hazard. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9.1.2 Functional requirements of each component sub-system shall be clearly defined to ensure that the integrated system meets the functional and specified safety requirements and takes account of any limitations of the equipment under control. Guidance note: Integrated system in this context is defined as a system which includes a combination of the two or more of the following functions control, monitoring and safety as required in this chapter. Integration of functions is permitted only for systems where independence is not required. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9.1.3 Key hazards of the integrated system shall be identified using appropriate risk based techniques.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 167

Part 5 Chapter 7 Section 13

8.1.5 The user interface shall be designed such that the equipment under control can be operated in a safe and effective manner at all times.

Guidance note: Reversionary control in this context is defined as alternative means of control that may be local manual or local automatic, whichever is chosen has to be suitable for the needs of the end user. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

9.1.5 Operation with an integrated system shall be at least as effective as it would be with individual standalone equipment or systems. 9.1.6 The integrity of essential machinery or systems, during normal operation and fault conditions, shall be demonstrated. 9.1.7 Where components in remote control systems are required to be designed with redundancy, or to be independent of each other, e.g. gas compressors and cargo pumps, redundancy or independence has also to be provided for in the control system.

10 Hold leakage alarm 10.1 General requirements 10.1.1 A device shall be provided in each hold space surrounding independent cargo tanks for giving alarm in case of leakage of water, oil or cargo into the holds.

11 Monitoring of thermal oxidation vapour systems 11.1 General requirements 11.1.1 Monitoring of thermal oxidation vapour system shall be as given in Table 1. Guidance note: Gas combustion unit is a thermal oxidation vapour system. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Table 1 Monitoring of thermal oxidation vapour system Item/parameter

Alarm

Shut down

Flame failure

X

X

Loss of combustion air supply

X

X

Loss of cooling air/dilution air supply

X

X

BOG inlet temperature

L

LL

Combustion gas exit temperature [HH at 535°C]

H

HH

Methane gas concentration in gas pipe duct

H

HH

Loss of ventilation in gas pipe duct, alternatively loss of N2 pressure

X

X

Fire detection in GCU compartment

X

X

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 168

Part 5 Chapter 7 Section 13

9.1.4 The integrated system shall have a suitable means of reversionary control.

Alarm

Shut down

Part 5 Chapter 7 Section 13

Item/parameter X= when happens, L= Low, LL= Low Low, H= High, HH= High High.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 169

12.1 General requirements 12.1.1 Monitoring of re-liquefaction system shall be as given in Table 2. Table 2 Monitoring of reliquefaction system Item/parameter*

Alarm

Shut down

BOG compressor, gas outlet temp.

H

HH

BOG compressor, gas outlet pressure

H

HH

BOG compressor, gas inlet pressure

Comment

H/L

BOG compressor, gas differential pressure

H

BOG compressor, gas inlet temp.

H

HH

BOG compressor, vibrations

H

HH

BOG compressor, lube oil press

L

LL

BOG compressor, bearings

H

HH

For shaft power above 1 500 kW.

BOG pre-cooler level

H

Refrigerant compressor gas inlet pressure

L

Refrigerant compressor gas inlet temp.

H

Refrigerant compressor gas outlet pressure

H

Refrigerant compressor, vibrations

H

HH

Only relevant for centrifugal compressors.

Refrigerant compressor lube oil press

L

LL

Refrigerant compressor, bearings

H

HH

Refrigerant high press/low press differential

X

ESD activated

Only relevant for centrifugal compressors.

For shaft power above 1 500 kW. Outside normal range.

X

Cargo tanks overfill danger

H

Mist separator (suction drum) level or temperature

L

Loss of power supply to control and monitoring system

X

HH Ensure that no liquid into BOG compressor. X

*BOG is Boil-off Gas X= when happens, L= Low, LL= Low Low, H= High, HH= High High.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 170

Part 5 Chapter 7 Section 13

12 Monitoring of re-liquefaction plants

12.2.1 Monitoring of re-liquefaction system (Brayton cycle) for methane (LNG) shall be as given in Table 2 and Table 3. Table 3 Monitoring of re-liquefaction system (Brayton cycle) for methane (LNG) Item/parameter* BOG pre-cooler level

Alarm

Shut down

Comment

H

Vapour header pressure

H/L

LNG separator level

H/L

LNG separator, pressure

H/L

Cold box enclosure, gas concentration — methane

LL

—H —L

— oxygen Cooling water press.

L

Cooling water outlet temp.

H

N2 compressor room, O2 concentration

L

N2 compressor room, loss of ventilation

X

N2 rejection column, level

H

N2 rejection column, pressure BOG compressor room O2 concentration

H/L L

X= when happens, L= Low, LL= Low Low, H= High, HH= High High.

13 Monitoring of inert gas generator 13.1 General requirements 13.1.1 Monitoring of inert gas generator shall be as given in Table 4. Table 4 Monitoring of inert gas generator Failure

Alarm

Shutdown

Oxygen content > 5%

X

X

High water level in scrubber

X

Low water pressure /flow to scrubber

X

Failure of blowers

X

X

Flame failure

X

X

Power failure instrumentation

X

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 171

Part 5 Chapter 7 Section 13

12.2 Re-liquefaction system (Brayton cycle) for methane (LNG)

Alarm

Insufficient fuel supply

Shutdown

Part 5 Chapter 7 Section 13

Failure

X

14 Monitoring of nitrogen generator 14.1 General arrangement 14.1.1 Monitoring of nitrogen gas generator shall be as given in Table 5. Table 5 Monitoring of nitrogen gas generator Failure

Alarm

Shutdown

High oxygen content > 5%

X

X, 1

Low pressure of nitrogen

X

Low pressure feed air supply

X

High temperature feed air supply

X

Failure of electrical heater, if fitted

X

High condensate level at automatic drain of water separator, if fitted

X

Power failure instrumentation

X

Block and bleed valve faulty operation with inconsistency valve positions, if fitted

X

2

Notes: 1) Alternatively automatically vented to atmosphere. 2) Nitrogen separating systems that may be destroyed by high temperature in the supply air shall be arranged with automatic shutdown of the system upon alarm conditions. Guidance note: The safety shutdowns required by [14] may be handled by the same control system as the control and alarm functions, i.e. exempted from the independency requirement of Pt.4 Ch.9 Sec.3 [1.1.3]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 172

15.1 General arrangement 15.1.1 Guidance on different alarm and shut down are given in Table 6. Table 6 Alarm and shut down Parameter

Item description

Alarm

Airlocks

One open door in airlock or doors on both sides of airlock are moved from closed position.

X

Vacuum protection systems

Under pressure of cargo tanks.

X

Inert gas production on board

Detection of oxygen content by volume more than 5% in inert gas supply from equipment.

X

Cargo pumps

Low-liquid level in cargo containment system when cargo pump motors and their supply cables are fitted in the cargo containment system.

X

Failure of ventilation in spaces dependent in ventilation for its area Ventilation arrangement classification. and capacity Failure of the overpressure requirements ventilation non-hazardous spaces with opening to hazardous areas. High liquid level in cargo tank. Overflow control

Shutdown

X

Rule reference

Comment

Sec.3 [6.1.3]

Visible alarm or audible alarm on both sides of airlock.

Sec.8 [3.1.1]

Sec.9 [2.1.1]

X

Sec.10 [1.3.9]

X

Sec.12 [3.1.8] .3

Audible and visual alarm.

X

Sec.12 [3.2.1] .3

Audible and visual alarm.

X

[3.1.1]

See also [3.1.4].

High high liquid level in cargo tank.

X

[3.1.2]

Unintended stop of pump when pumps situated in different tanks discharge into common header in cargo transfer arrangement.

X

[3.1.8]

Pressure monitoring

Before pressure monitoring reaching set pressure.

X

[4.1.2]

Gas detection

If gas detection equipment is located in an enclosure in a non-hazardous space and gas concentrations in enclosure reaches above 30% of lower flammable limit (LFL).

X

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

[6.1.9]

Shut down of gas detection equipment.

Page 173

Part 5 Chapter 7 Section 13

15 Guidance on alarm and shut down

Item description

Vapour concentration by volume reaches 30% of the LFL.

Vapour concentration by volume in primary and seconday insulation.

Alarm

Shutdown

X

X

Vapour concentration reaches 60% LFL as required in Sec.16. Before 100% LFL in crankcase of internal combustion engines that can run on gas.

X

X

Additional requirements for Temperatures approaching the containment lowest for which the hull steel is systems suitable. requiring a secondary barrier

X

Leakage in the piping system in enclosed spaces.

X

Gas detection when using gas as fuel at 30% LFL.

X

Gas fuel supply

Gas detection when using gas as fuel at 60% LFL.

Gas fuel plant and related storage tanks

Special requirements for main boilers

Rule reference

Comment

[6.1.15] and [6.1.17]

See also [6.1.4] and includes inerted hold spaces and interbarrier spaces.

[6.1.16]

Shall be 30% LEL for secondary barrier space, while primary insulation space can be set to value accepted by the Society.

[6.1.17]

[6.1.17]

[7.2.2]

X

Sec.16 [4.2.1] Sec.16 [4.8.1]

X

Sec.16 [4.8.1]

Abnormal pressure in the gas fuel supply line of failure of the valve control actuating medium.

X

Sec.16 [5.2.3]

Heating of cooling medium for the gas fuel conditioning system is returned to spaces outside the cargo area.

X

Sec.16 [5.3.1]

Discontinuous availability in automatic fuel changeover system.

X

Sec.16 [6.3.4]

Decrease in liquid fuel oil pressure or a failure of the related pumps.

X

Sec.16 [6.3.8]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

When cargo is carried in a cargo containment system with a secondary barrier, at a temperature lower than -55°C.

Shut down master gas fuel valve.

Page 174

Part 5 Chapter 7 Section 13

Parameter

Item description

Alarm

Shutdown

Rule reference

Comment

X

Sec.16 [7.3.5]

Shut down fuel supply.

Poor combustion of mis-firing in gas turbine.

X

Sec.16 [8.3.1]

High exhaust temperatures in gas turbines.

X

Sec.16 [8.3.2]

Special requirements for gasPoor combustion of mis-firing in fired internal combustion engine. combustion engines Special requirements for gas turbine

Chlorine

Methyl acetylenepropadiene mixtures

Carbon dioxide

Pressure equal to 1.05 MPa in cargo tanks.

X

Sec.17 [3.4.4]

Audible alarm.

Chlorine concentration of more than 5 ppm.

X

Sec.17 [3.4.3]

Audible and visible alarm.

When a high-pressure switch, or a high-temperature switch operates.

X

Sec.17 [6.1.4]

For composition given in Sec.17 [6.1.2], when discharge piping from vapour compression refrigeration stage or cylinder in compressor reach temperatures of 60°C or less.

X

Cargo tank low pressure for carbon dioxide.

X

Cargo tank low low pressure for carbon dioxide.

X

Cargo tank pressure reaches within 0.05 MPa of the triple point for the particular cargo.

Oxygen deficiency in hold spaces and compressor rooms in case of entrance to hold space is from any enclosed space specified in Sec.17 [11.1.10].

Sec.17 [11.1.1] X

X

X

Cargo emergency shutdown (ESD) system

Sec.17 [6.1.4]

Sec.17 [11.1.4]

Sec.17 [11.1.4]

Automatic closing of all cargo manifold liquid and vapour valves and stop all cargo compressors and cargo pumps.

Sec.17 [11.1.8]

Sec.18 Table 1

Thermal oxidation vapour system

Table 1

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Normally called gas combustion unit

Page 175

Part 5 Chapter 7 Section 13

Parameter

Item description

Alarm

Shutdown

Rule reference

Reliquefaction plants

Table 2 and Table 3

Reliquefaction plants (brayton cycle)

Table 2 and Table 3

Inert gas generator

Table 4

Nitrogen generator

Table 5

Comment

Notes: This table can only be used for guidance

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 176

Part 5 Chapter 7 Section 13

Parameter

1 General requirements for all products 1.1 Protective equipment 1.1.1 Suitable protective equipment, including eye protection shall be provided for protection of crew members engaged in normal cargo operations, taking into account the characteristics of the products being carried. 1.1.2 Personal protective and safety equipment required shall be kept in suitable, clearly marked lockers located in readily accessible places. 1.1.3 The compressed air equipment shall be inspected at least once a month by a responsible officer and the inspection logged in the ship's records. This equipment shall also be inspected and tested by a competent person at least once a year.

1.2 First-aid equipment 1.2.1 A stretcher that is suitable for hoisting an injured person from spaces below deck shall be kept in a readily accessible location. 1.2.2 The ship shall have on board medical first aid equipment, including oxygen resuscitation equipment, based on the requirements of the medical first aid guide (MFAG) for the cargoes to be carried.

1.3 Safety equipment 1.3.1 Sufficient, but not less than three complete sets of safety equipment shall be provided in addition to the firefighter's outfits required by Sec.11 [6.1]. Each set shall provide adequate personal protection to permit entry and work in a gas-filled space. This equipment shall take into account the nature of the cargoes to be carried. 1.3.2 Each complete set of safety equipment shall consist of:

.1

one self-contained positive pressure air breathing apparatus incorporating full face mask, not using stored oxygen and having a capacity of at least 1200 litres of free air. Each set shall be compatible with that required by Sec.11 [6.1]

.2 .3 .4

protective clothing, boots and gloves steel cored rescue line with belt, and explosion proof lamp.

1.3.3 An adequate supply of compressed air shall be provided and shall consist of:

.1

at least one fully charged spare air bottle for each breathing apparatus required by [1.3.1], in accordance with the requirements of Sec.11 [6.1]

.2

an air compressor of adequate capacity capable of continuous operation, suitable for the supply of high pressure air of breathable quality, and

.3

a charging manifold capable of dealing with sufficient spare breathing apparatus air bottles for the breathing apparatus required by [1.3.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 177

Part 5 Chapter 7 Section 14

SECTION 14 PERSONNEL PROTECTION

2.1 General requirements Provisions of [2] shall apply to ships carrying products for which those paragraphs are listed in column i in Sec.19 Table 2. 2.1.1 Suitable respiratory and eye protection suitable for emergency escape purposes shall be provided for every person on board, subject to the following:

.1 .2 .3

Filter type respiratory protection is unacceptable. Self-contained breathing apparatus is normally to have a duration of service of at least 15 min, and: Emergency escape respiratory protection shall not be used for fire-fighting or cargo handling purposes and should be marked to that effect.

2.1.2 One or more suitably marked decontamination showers and eyewash stations shall be available on deck, taking into account the size and layout of vessel. The showers and eyewashes shall be operable in all ambient conditions. Guidance note: Decontamination showers and eye wash units should be located on both sides of the ship in the cargo manifold area and in way of the cargo compressor room. For small ships, reduced number of showers and eye wash can be considered. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.3 The protective clothing required under [1.3.2].2 shall be gastight.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 178

Part 5 Chapter 7 Section 14

2 Personal protection requirements for individual products

1 General 1.1 Definitions 1.1.1 Filling limit (FL) means the maximum liquid volume in a cargo tank relative to the total tank volume when the liquid cargo has reached the reference temperature. 1.1.2 Loading limit (LL) means the maximum allowable liquid volume relative to the tank volume to which the tank may be loaded. 1.1.3 Reference temperature means, for the purposes of this section only:

.1

when no cargo vapour pressure/temperature control, as referred to in Sec.7, is provided, the temperature corresponding to the vapour pressure of the cargo at the set pressure of the PRVs, and

.2

when a cargo vapour pressure/temperature control, as referred to in Sec.7, is provided, the temperature of the cargo upon termination of loading, during transport or at unloading, whichever is the greatest.

1.1.4 Ambient design temperature for unrestricted service means sea temperature of 32°C and air temperature of 45°C. However, lesser values of these temperatures may be accepted by the Society for ships operating in restricted areas or on voyages of restricted duration, and account may be taken in such cases of any insulation of the tanks. Conversely, higher values of these temperatures may be required for ships permanently operating in areas of high ambient temperature.

1.2 General requirements 1.2.1 The maximum filling limit of cargo tanks shall be so determined that the vapour space has a minimum volume at reference temperature allowing for:

.1 .2

tolerance of instrumentation such as level and temperature gauges

.3

an operational margin to account for liquid drained back to cargo tanks after completion of loading, operator reaction time and closing time of valves, see Sec.5 [5] and Sec.18 [2.2.4].

volumetric expansion of the cargo between the PRV set pressure and the maximum allowable rise stated in Sec.8 [4], and

1.3 Default filling limit 1.3.1 The default value for the filling limit (FL) of cargo tanks is 98% at the reference temperature. Exceptions to this value shall meet the requirements of [1.4].

1.4 Determination of increased filling limit 1.4.1 A filling limit greater than the limit of 98% specified in [1.3] on condition that, under the trim and list conditions specified in Sec.8 [2.2.15] may be permitted, providing:

.1 .2

no isolated vapour pockets are created within the cargo tank the PRV inlet arrangement shall remain in the vapour space, and

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 179

Part 5 Chapter 7 Section 15

SECTION 15 FILLING LIMIT OF CARGO TANKS

allowances need to be provided for:

.1

volumetric expansion of the liquid cargo due to the pressure increase from the MARVS to full flow relieving pressure in accordance with Sec.8 [4]

.2 .3

an operational margin of minimum 0.1% of tank volume, and tolerances of instrumentation such as level and temperature gauges.

1.4.2 In no case shall a filling limit exceeding 99.5% at reference temperature be permitted.

1.5 Maximum loading limit 1.5.1 The maximum loading limit (LL) to which a cargo tank may be loaded shall be determined by the following formula:

where:

LL FL ρR ρL

= loading limit as defined in [1.1.2] expressed in percentage = filling limit as specified in [1.3] or [1.4] expressed in percentage = relative density of cargo at the reference temperature = relative density of cargo at the loading temperature.

1.5.2 The Society may allow type C tanks to be loaded according to the formula in [1.5.1] with the relative density ρR as defined below, provided that the tank vent system has been approved in accordance with Sec.8 [2.2.16].

ρR = relative density of cargo at the highest temperature that the cargo may reach upon termination of

loading, during transport, or at unloading, under the ambient design temperature conditions described in [1.1.4].

This paragraph does not apply to products requiring a type 1G ship.

2 Information to be provided to the master 2.1 Documentation 2.1.1 A document shall be provided to the vessel specifying the maximum allowable loading limits for each cargo tank and product, at each applicable loading temperature and maximum reference temperature. The information in this document shall be approved by the Society. 2.1.2 Pressures at which the PRVs have been set shall also be stated in the document. 2.1.3 A copy of the above document shall be permanently kept on board by the master.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 180

Part 5 Chapter 7 Section 15

.3

1 General 1.1 Requirements 1.1.1 Except as provided for in [9], methane (LNG) is the only cargo whose vapour or boil-off gas may be utilized in machinery spaces of category A, and in these spaces it may be utilized only in systems such as boilers, inert gas generators, internal combustion engines, gas combustion unit (GCU) and gas turbines. 1.1.2 Alarm and safety systems shall comply with the requirements in this section and Pt.4 Ch.9. A dedicated gas safety system, independent of the gas control system, shall be arranged in accordance with the general principles in Pt.4 Ch.9 Sec.3 [1.1.3].

2 Use of cargo vapour as fuel 2.1 General requirements This section addresses the use of cargo vapour as fuel in systems such as boilers, inert gas generators, internal combustion engines, gas combustion units (GCU) and gas turbines. 2.1.1 For vaporized LNG, the fuel supply system shall comply with the requirements of [4.1] to [4.3]. 2.1.2 For vaporized LNG, gas consumers shall exhibit no visible flame and shall maintain the uptake exhaust temperature below 535°C. Guidance note: Thermal oxidation of vapours is covered in Sec.7 [4]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3 Arrangement of spaces containing gas consumers 3.1 General requirements 3.1.1 Spaces in which gas consumers are located shall be fitted with a mechanical ventilation system that is arranged to avoid areas where gas may accumulate, taking into account the density of the vapour and potential ignition sources. The ventilation system shall be separated from those serving other spaces. 3.1.2 Gas detectors shall be fitted in these spaces, particularly where air circulation is reduced. The gas detection system shall comply with the requirements of Sec.13. 3.1.3 Electrical equipment located in the double wall pipe or duct specified in [4.3] shall comply with the requirements of Sec.10. 3.1.4 All vents and bleed lines that may contain or be contaminated by gas fuel shall be routed to a safe location external to the machinery space and be fitted with a flame screen.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 181

Part 5 Chapter 7 Section 16

SECTION 16 USE OF GAS FUEL

4.1 General requirements 4.1.1 The requirements of [4] shall apply to gas fuel supply piping outside of the cargo area. Fuel piping shall not pass through accommodation spaces, service spaces, electrical equipment rooms or control stations. The routeing of the pipeline shall take into account potential hazards due to mechanical damage, such as stores or machinery handling areas. 4.1.2 Provision shall be made for inerting and gas-freeing that portion of the gas fuel piping systems located in the machinery space.

4.2 Leak detection 4.2.1 Continuous monitoring and alarms shall be provided to indicate a leak in the piping system in enclosed spaces and shut down the relevant gas fuel supply.

4.3 Routeing of fuel supply pipes 4.3.1 Fuel piping may pass through or extend into enclosed spaces other than those mentioned in [4.1], provided that it fulfils one of the following conditions:

.1

A double wall design with the space between the concentric pipes pressurized with inert gas at a pressure greater than the gas fuel pressure. The isolating valve, as required by [4.5], closes automatically upon loss of inert gas pressure, or

.2

Installed in a pipe or duct equipped with mechanical exhaust ventilation having a capacity of at least 30 air changes per hour, and be arranged to maintain a pressure less than the atmospheric pressure. The mechanical ventilation is in accordance with Sec.12 as applicable. The ventilation is always in operation when there is fuel in the piping and the isolating valve, as required by [4.5], closes automatically if the required air flow is not established and maintained by the exhaust ventilation system. The inlet or the duct may be from a non-hazardous machinery space and the ventilation outlet is in a safe location. Guidance note: Condensation in annular space in double wall fuel gas piping shall be prevented, e.g. by heating fuel gas above the inlet air temperature or drying the ventilation air. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.4 Requirements for gas fuel with pressure greater than 1 MPa 4.4.1 Fuel delivery lines between the high pressure fuel pumps/compressor and consumers shall be protected with a double-walled piping system capable of containing a high pressure line failure, taking into account the effects of both pressure and low temperature. A single walled pipe in the cargo area up to the isolating valve(s) required by [4.6] is acceptable. 4.4.2 The arrangement in [4.3.1].2 may also be acceptable providing the pipe or trunk is capable of containing a high pressure line failure, according to the requirements of [4.7] and taking into account the effects of both pressure and possible low temperature and providing both inlet and exhaust of the outer pipe or trunk are in the cargo area.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 182

Part 5 Chapter 7 Section 16

4 Gas fuel supply

4.5.1 The supply piping of each gas consumer unit shall be provided with gas fuel isolation by automatic double block and bleed, vented to a safe location, under both normal and emergency operation. The automatic valves shall be arranged to fail to the closed position on loss of actuating power. In a space containing multiple consumers, the shutdown of one shall not affect the gas supply to the others.

4.6 Spaces containing gas consumers 4.6.1 It shall be possible to isolate the gas fuel supply to each individual space containing a gas consumer(s) or through which fuel gas supply piping is run, with an individual master valve, which is located within the cargo area. The isolation of gas fuel supply to a space shall not affect the gas supply to other spaces containing gas consumers if they are located in two or more spaces, and it shall not cause loss of propulsion or electrical power. 4.6.2 If the double barrier around the gas supply system is not continuous due to air inlets or other openings, or if there is any point where single failure will cause leakage into the space, it shall be possible to isolate the gas fuel supply to each individual space by means of an individual master gas fuel valve, which shall be located within the cargo area. This valve shall operate:

.1

automatically by:

.1 .2 .3 .4 .5 .2

gas detection within the space leak detection in the annular space of a double walled pipe leak detection in other compartments inside the space, containing single walled gas piping loss of ventilation in the annular space of a double walled pipe; and loss of ventilation in other compartments inside the space, containing single walled gas piping, and

manually from within the space, and at least one remote location.

4.6.3 If the double barrier around the gas supply system is continuous, an individual master valve located in the cargo area may be provided for each gas consumer inside the space. The individual master valve shall operate:

.1

.2

automatically by:

.1

leak detection in the annular space of a double walled pipe served by that individual master valve

.2

leak detection in other compartments containing single-walled gas piping that is part of the supply system served by that individual master valve; and

.3

loss of ventilation or loss of pressure in the annular space of a double walled pipe; and

manually from within the space, and at least one remote location.

4.7 Piping and ducting construction 4.7.1 Gas fuel piping in machinery spaces shall comply with Sec.5 [1] to Sec.5 [9], as applicable. The piping shall, as far as practicable, have welded joints. Those parts of the gas fuel piping that are not enclosed in a ventilated pipe or duct according to [4.3], and are on the weather decks outside the cargo area, shall have full penetration butt-welded joints and shall be fully radiographed.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 183

Part 5 Chapter 7 Section 16

4.5 Gas consumer isolation

4.8.1 Gas detection systems provided in accordance with the requirements of this section shall activate the alarm at 30% LFL and shut down the master gas fuel valve required by [4.6] at not more than 60% LFL. See also Sec.13 [6.1.17].

5 Gas fuel plant and related storage tanks 5.1 Provision of gas fuel 5.1.1 All equipment, e.g. heaters, compressors, vaporizers, filters, for conditioning the cargo and/or cargo boil-off vapour for its use as fuel, and any related storage tanks, shall be located in the cargo area. If the equipment is in an enclosed space, the space shall be ventilated according to Sec.12 [1] and be equipped with a fixed fire-extinguishing system, according to Sec.11 [5], and with a gas detection system according to Sec.13 [6], as applicable.

5.2 Remote stops and alarm 5.2.1 All rotating equipment utilized for conditioning the cargo for its use as fuel, shall be arranged for manual remote stop from the engine room. Additional remote stops shall be located in areas that are always easily accessible, typically cargo control room, navigation bridge and fire control station. 5.2.2 The fuel supply equipment shall be automatically stopped in the case of low suction pressure or fire detection. Gas fuel compressors or pumps are not required to fulfil Sec.18 [2.1.1],when used to supply gas consumers. 5.2.3 Alarm should be given for abnormal pressure in the gas fuel supply line or for failure of the valve control actuating medium.

5.3 Heating and cooling mediums 5.3.1 If the heating or cooling medium for the gas fuel conditioning system is returned to spaces outside the cargo area, provisions shall be made to detect and alarm the presence of cargo/cargo vapour in the medium. Any vent outlet shall be in a safe position and fitted with an effective flame screen of an approved type.

5.4 Piping and pressure vessels 5.4.1 Piping or pressure vessels fitted in the gas fuel supply system shall comply with Sec.5.

6 Special requirements for main boilers 6.1 Arrangements 6.1.1 Each boiler shall have a separate exhaust uptake. 6.1.2 Each boiler shall have a dedicated forced draught system. A crossover between boiler force draught systems may be fitted for emergency use providing that any relevant safety functions are maintained.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 184

Part 5 Chapter 7 Section 16

4.8 Gas detection

6.2 Combustion equipment 6.2.1 The burner systems shall be of dual type, suitable to burn either: oil fuel or gas fuel alone, or oil and gas fuel simultaneously. 6.2.2 Burners shall be designed to maintain stable combustion under all firing conditions. 6.2.3 An automatic system shall be fitted to change over from gas fuel operation to oil fuel operation without interruption of the boiler firing, in the event of loss of gas fuel supply. 6.2.4 Gas nozzles and the burner control system shall be configured such that gas fuel can only be ignited by an established oil fuel flame, unless the boiler and combustion equipment is designed and approved by the Society to light on gas fuel.

6.3 Safety 6.3.1 There shall be arrangements to ensure that gas fuel flow to the burner is automatically cut-off, unless satisfactory ignition has been established and maintained. 6.3.2 On the pipe of each gas burner a manually operated shut-off valve shall be fitted. 6.3.3 Provisions shall be made for automatically purging the gas supply piping to the burners, by means of an inert gas, after the extinguishing of these burners. 6.3.4 The automatic fuel changeover system required by [6.2.3] shall be monitored with alarms to ensure continuous availability. 6.3.5 Arrangements shall be made that, in case of flame failure of all operating burners, the combustion chambers of the boilers are automatically purged before relighting. 6.3.6 Arrangements shall be made to enable the boilers to be manually purged. 6.3.7 Oxygen content in the exhaust gas line shall be indicated. 6.3.8 Alarm devices shall be fitted in order to monitor a possible decrease in liquid fuel oil pressure or a possible failure of the related pumps. 6.3.9 The extent of monitoring of gas fired boilers shall comply with the requirements specified in Pt.4 Ch.7 for oil fired boilers. 6.3.10 At the operating stations for the boilers, a readily visible signboard with the following instruction shall be posted: CAUTION: NO BURNER SHALL BE FIRED BEFORE THE FURNACE HAS BEEN PROPERLY PURGED.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 185

Part 5 Chapter 7 Section 16

6.1.3 Combustion chambers and uptakes of boilers shall be designed to prevent any accumulation of gaseous fuel.

Dual fuel engines are those that employ gas fuel (with pilot oil) and oil fuel. Oil fuels may include distillate and residual fuels. Gas only engines are those that employ gas fuel only.

7.1 Arrangements 7.1.1 When gas is supplied in a mixture with air through a common manifold, flame arrestors shall be installed before each cylinder head. 7.1.2 Each engine shall have its own separate exhaust. 7.1.3 The exhausts shall be configured to prevent any accumulation of un-burnt gaseous fuel. 7.1.4 Unless designed with the strength to withstand the worst case over pressure due to ignited gas leaks, air inlet manifolds, scavenge spaces, exhaust system and crank cases shall be fitted with suitable pressure relief systems. Pressure relief systems shall lead to a safe location, away from personnel. 7.1.5 Each engine shall be fitted with vent systems independent of other engines for crankcases, sumps and cooling systems.

7.2 Combustion equipment 7.2.1 Prior to admission of gas fuel, correct operation of the pilot oil injection system on each unit shall be verified. 7.2.2 For a spark ignition engine, if ignition has not been detected by the engine monitoring system within an engine specific time after opening of the gas supply valve, this shall be automatically shut-off and the starting sequence terminated. It shall be ensured that any unburned gas mixture is purged from the exhaust system. 7.2.3 For dual fuel engines fitted with a pilot oil injection system, an automatic system shall be fitted to change over from gas fuel operation to oil fuel operation with minimum fluctuation of the engine power. 7.2.4 In the case of unstable operation on engines with the arrangement in [7.2.3] when gas firing, the engine shall automatically change to oil fuel mode.

7.3 Safety 7.3.1 During stopping of the engine the gas fuel shall be automatically shut-off before the ignition source. 7.3.2 Arrangements shall be provided to ensure that there is no unburned gas fuel in the exhaust gas system prior to ignition. 7.3.3 Crankcases, sumps, scavenge spaces and cooling system vents shall be provided with gas detection, see Sec.13 [6.1.17]. Guidance note: Gas detection in crankcase vent will be acceptable. One common gas detector for crankcase vent of multi engines is acceptable. For sump tanks, scavenge spaces and cooling water vents individual sensors is required. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 186

Part 5 Chapter 7 Section 16

7 Special requirements for gas-fired internal combustion engines

7.3.5 A means shall be provided to monitor and detect poor combustion or mis-firing that may lead to unburned gas fuel in the exhaust system during operation. In the event that it is detected, the gas fuel supply shall be shut down. Instrumentation fitted inside the exhaust system shall be in accordance with the requirements of Sec.10.

8 Special requirements for gas turbine 8.1 Arrangements 8.1.1 Each turbine shall have its own separate exhaust. 8.1.2 The exhausts shall be appropriately configured to prevent any accumulation of un-burnt gas fuel. 8.1.3 Unless designed with the strength to withstand the worst case over pressure due to ignited gas leaks, pressure relief systems shall be suitably designed and fitted to the exhaust system, taking into consideration of explosions due to gas leaks. Pressure relief systems within the exhaust uptakes shall be lead to a nonhazardous location, away from personnel.

8.2 Combustion equipment An automatic system shall be fitted to change over easily and quickly from gas fuel operation to oil fuel operation with minimum fluctuation of the engine power.

8.3 Safety 8.3.1 Means shall be provided to monitor and detect poor combustion that may lead to unburned gas fuel in the exhaust system during operation. In the event such unburned gas fuel is detected, the gas fuel supply shall be shut down. 8.3.2 Each turbine shall be fitted with an automatic shutdown device for high exhaust temperatures.

9 Alternative fuels and technologies 9.1 General requirements 9.1.1 If acceptable to the Society, other cargo gases may be used as fuel, providing that the same level of safety as natural gas in this section is ensured. 9.1.2 The use of cargoes identified as toxic in Sec.19 are not permitted. 9.1.3 For cargoes other than LNG, the fuel supply system shall comply with the requirements of [4.1], [4.2], [4.3] and [5], as applicable, and shall include means for preventing condensation of vapour in the system. 9.1.4 Liquefied gas fuel supply systems shall comply with [4.5]. 9.1.5 In addition to the requirements of [4.3.1].2, both ventilation inlet and outlet shall be located outside the machinery space. The inlet shall be in a non-hazardous area and the outlet shall be in a safe location.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 187

Part 5 Chapter 7 Section 16

7.3.4 Provision shall be made within the design of the engine to permit continuous monitoring of possible sources of ignition within the crank case. Instrumentation fitted inside the crankcase shall be in accordance with the requirements of Sec.10.

10.1 General requirements and safety 10.1.1 The requirements of this sub-section apply for single fuel installations with gas only. 10.1.2 The fuel supply system shall be arranged with full redundancy with separate master gas valves and full segregation all the way from the cargo tanks to the consumer, so that a single failure does not lead to loss of propulsion, power generation or other main function. 10.1.3 Power supply to spray water and fire main pumps shall be provided by power source not depending on gas supply. Guidance note: This requirement means that the spray water pumps shall be driven by diesel engine or alternatively one of the generators driven by diesel or duel fuel engine. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

10.1.4 Each fuel gas system shall be fitted with its own set of independent gas control and gas safety systems. 10.1.5 Gas supply lines with master gas valves should be located as far as possible from each other.

11 Gas fuel operation manual 11.1 General requirements 11.1.1 A gas fuel operational manual shall be kept onboard and may be part of the required operation manual required in Sec.18 [1]. The gas fuel operation manual should give information regarding the following:

.1 .2 .3 .4 .5

Descriptions of main components in the gas fuel supply system A general description of how the fuel system is intended to work Description of the safety shut-down system for the gas fuel supply system Safety pre-cautions related to maintenance Relevant drawings of the gas fuel installation, including: — fuel gas piping diagram — fuel gas system arrangement plan — ventilation systems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 188

Part 5 Chapter 7 Section 16

10 Gas only installations

1 General The provisions of this section are applicable where reference is made in column i in Sec.19 Table 2. These are requirements additional to the general requirements of the rule set.

1.1 Materials of construction 1.1.1 Materials that may be exposed to cargo during normal operations shall be resistant to the corrosive action of the gases. In addition, the following materials of construction for cargo tanks and associated pipelines, valves, fittings and other items of equipment normally in direct contact with the cargo liquid or vapour, shall not be used for certain products as specified in column i in Sec.19 Table 2:

.1 .2 .3 .4 .5 .6

mercury, copper and copper-bearing alloys, and zinc copper, silver, mercury, magnesium and other acetylide-forming metals aluminium and aluminium-bearing alloys copper, copper alloys, zinc and galvanized steel aluminium, copper and alloys of either, and copper and copper-bearing alloys with greater than 1% copper.

1.2 Independent tanks 1.2.1 Products shall be carried in independent tanks only. 1.2.2 Products shall be carried in type C independent tanks and the provisions of Sec.7 [1.1.2] shall apply. The design pressure of the cargo tank shall take into account any padding pressure or vapour discharge unloading pressure.

1.3 Refrigeration systems 1.3.1 Only the indirect system described in Sec.7 [3.1.1] .2 shall be used. 1.3.2 For a ship engaged in the carriage of products that readily form dangerous peroxides, re-condensed cargo shall not be allowed to form stagnant pockets of uninhibited liquid. This may be achieved by one of the following methods:

.1 .2

using the indirect system described in Sec.7 [3.1.1] .2, with the condenser inside the cargo tank, or using the direct system or combined system described in Sec.7 [3.1.1] .1 and Sec.7 [3.1.1].3, respectively, or the indirect system described in Sec.7 [3.1.1] .2 with the condenser outside the cargo tank, and designing the condensate system to avoid any places in which liquid could collect and be retained. Where this is impossible, inhibited liquid shall be added upstream of such a place.

1.3.3 If the ship shall consecutively carry products as specified in [1.3.2] with a ballast passage between, all uninhibited liquid shall be removed prior to the ballast voyage. If a second cargo shall be carried between such consecutive cargoes, the reliquefaction system shall be thoroughly drained and purged before loading the second cargo. Purging shall be carried out using either inert gas or vapour from the second cargo, if compatible. Practical steps shall be taken to ensure that polymers or peroxides do not accumulate in the cargo system.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 189

Part 5 Chapter 7 Section 17

SECTION 17 SPECIAL REQUIREMENTS

1.4.1 All butt-welded joints in cargo piping exceeding 75 mm in diameter shall be subject to 100% radiography. 1.4.2 Gas sampling lines shall not be led into or through non-hazardous areas. Alarms referred to in Sec.13 [6.1.2] shall be activated when the vapour concentration reaches the threshold limiting value. 1.4.3 The alternative of using portable gas detection equipment in accordance with Sec.13 [6.1.5] shall not be permitted. 1.4.4 Cargo control rooms shall be located in a non-hazardous area and, additionally, all instrumentation shall be of the indirect type. 1.4.5 Personnel shall be protected against the effects of a major cargo release by the provision of a space within the accommodation area that is designed and equipped to the satisfaction of the Society. 1.4.6 Notwithstanding the provision in Sec.3 [2.1.4] .3, access to forecastle spaces shall not be permitted through a door facing the cargo area unless airlock in accordance with Sec.3 [6] is provided. 1.4.7 Notwithstanding the provision in Sec.3 [2.1.7], access to control rooms and machinery spaces of turret systems shall not be permitted through doors facing the cargo area.

1.5 Exclusion of air from vapour spaces Air shall be removed from cargo tanks and associated piping before loading and then subsequently excluded by one of the following methods:

.1

introducing inert gas to maintain a positive pressure. Storage or production capacity of the inert gas shall be sufficient to meet normal operating requirements and relief valve leakage. The oxygen content of inert gas shall at no time be greater than 0.2% by volume, or

.2

control of cargo temperatures such that a positive pressure is maintained at all times.

1.6 Moisture control For gases that are non-flammable and may become corrosive or react dangerously with water, moisture control shall be provided to ensure that cargo tanks are dry before loading and that, during discharge, dry air or cargo vapour is introduced to prevent negative pressures. For the purposes of this paragraph, dry air is air that has a dew point of -45°C or below at atmospheric pressure.

1.7 Inhibition 1.7.1 Care shall be taken to ensure that the cargo is sufficiently inhibited to prevent self-reaction, e.g. polymerization or dimerization, at all times during the voyage. Ships shall be provided with a certificate from the manufacturer stating:

.1 .2 .3 .4

name and amount of inhibitor added date inhibitor was added and the normally expected duration of its effectiveness any temperature limitations affecting the inhibitor, and the action to be taken shall the length of the voyage exceed the effective lifetime of the inhibitors.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 190

Part 5 Chapter 7 Section 17

1.4 Cargoes requiring type 1G ship

1.8.1 When carrying a cargo referenced to this section, cargo tank vent outlets shall be provided with readily renewable and effective flame screens or safety heads of an approved type. Due attention shall be paid to the design of flame screens and vent heads, to the possibility of the blockage of these devices by the freezing of cargo vapour or by icing up in adverse weather conditions. Flame screens shall be removed and replaced by protection screens in accordance with Sec.8 [2.2.13] when carrying cargoes not referenced to this section.

1.9 Maximum allowable quantity of cargo per tank 1.9.1 When carrying a cargo referenced to in this section, the quantity of the cargo shall not exceed 3000 m in any tank.

3

1.10 Cargo pumps and discharge arrangements 1.10.1 The vapour space of cargo tanks equipped with submerged electric motor pumps shall be inerted to a positive pressure prior to loading, during carriage and during unloading of flammable liquids. 1.10.2 The cargo shall be discharged only by deepwell pumps or by hydraulically operated submerged pumps. These pumps shall be of a type designed to avoid liquid pressure against the shaft gland. 1.10.3 Inert gas displacement may be used for discharging cargo from type C independent tanks, provided the cargo system is designed for the expected pressure.

2 Ammonia 2.1 General requirements 2.1.1 Anhydrous ammonia may cause stress corrosion cracking in containment and process systems made of carbon-manganese steel or nickel steel. To minimize the risk of this occurring, measures detailed in [2.1.2] to [2.1.8] shall be taken, as appropriate. 2.1.2 Where carbon-manganese steel is used, cargo tanks, process pressure vessels and cargo piping 2 shall be made of fine-grained steel with a specified minimum yield strength not exceeding 355 N/mm , and 2 with an actual yield strength not exceeding 440 N/mm . One of the following constructional or operational measures shall also be taken: 2

.1

lower strength material with a specified minimum tensile strength not exceeding 410 N/mm shall be used, or

.2 .3

cargo tanks, etc., shall be post-weld stress relief heat treated, or

.4

the ammonia shall contain not less than 0.1% w/w water and the master shall be provided with documentation confirming this.

carriage temperature shall be maintained, preferably at a temperature close to the product's boiling point of -33°C, but in no case at a temperature above -20°C, or

2.1.3 If carbon-manganese steels with higher yield properties are used other than those specified in [2.1.2], the completed cargo tanks, piping, etc., shall be given a post-weld stress relief heat treatment. 2.1.4 Process pressure vessels and piping of the condensate part of the refrigeration system shall be given a post-weld stress relief heat treatment when made of materials mentioned in [2.1.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 191

Part 5 Chapter 7 Section 17

1.8 Flame screens on vent outlets

2.1.6 Nickel steel containing more than 5% nickel and carbon-manganese steel, not complying with the requirements of [2.1.2] and [2.1.3], are particularly susceptible to ammonia stress corrosion cracking and shall not be used in containment and piping systems for the carriage of this product. 2.1.7 Nickel steel containing not more than 5% nickel may be used provided the carriage temperature complies with the requirements specified in [2.1.2] .3. 2.1.8 To minimize the risk of ammonia stress corrosion cracking, it is advisable to keep the dissolved oxygen content below 2.5 ppm w/w. This can best be achieved by reducing the average oxygen content in the tanks prior to the introduction of liquid ammonia to less than the values given as a function of the carriage temperature T in the table below: Table 1 Ammonia stress corrosion cracking T in °C

O2 in % by volume

-30 and below

0.90

–20

0.50

–10

0.28

0

0.16

+10

0.10

+20

0.05

+30

0.03

Oxygen % for intermediate temperatures may be obtained by direct interpolation.

3 Chlorine 3.1 Cargo containment system 3

3.1.1 The capacity of each tank shall not exceed 600 m and the total capacity of all cargo tanks shall not 3 exceed 1200 m . 3.1.2 The tank design vapour pressure shall not be less than 1.35 MPa, see also Sec.7 [1.1.2] and [1.2.2]. 3.1.3 Parts of tanks protruding above the upper deck shall be provided with protection against thermal radiation, taking into account total engulfment by fire. 3.1.4 Each tank shall be provided with two PRVs. A bursting disc of appropriate material shall be installed between the tank and the PRVs. The rupture pressure of the bursting disc shall be 1 bar lower than the opening pressure of the pressure relief valve, which shall be set at the design vapour pressure of the tank but not less than 1.35 MPa bar gauge. The space between the bursting disc and the relief valve shall be connected through an excess flow valve to a pressure gauge and a gas detection system. Provision shall be made to keep this space at or near the atmospheric pressure during normal operation.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 192

Part 5 Chapter 7 Section 17

2.1.5 The tensile and yield properties of the welding consumables shall exceed those of the tank or piping material by the smallest practical amount.

3.1.6 The national regulations and the port administration may require that chlorine is carried in a refrigerated state at a specified maximum pressure.

3.2 Cargo piping systems 3.2.1 Cargo discharge shall be performed by means of compressed chlorine vapour from shore, dry air or another acceptable gas, or fully submerged pumps. Cargo discharge compressors on board ships shall not be used for this. The pressure in the vapour space of the tank during discharging shall not exceed 1.05 MPa. 3.2.2 The design pressure of the cargo piping system shall be not less than 2.1 MPa. The internal diameter of the cargo pipes shall not exceed 100 mm. Only pipe bends shall be accepted for compensation of pipeline thermal movement. The use of flanged joints shall be restricted to a minimum and, when used the flanges, shall be of the welding neck type with tongue and groove. 3.2.3 Relief valves of the cargo piping system shall discharge to the absorption plant, and the flow restriction created by this unit shall be taken into account when designing the relief valve system, see also Sec.8 [2.2.16].

3.3 Materials 3.3.1 The cargo tanks and cargo piping systems shall be made of steel suitable for the cargo and for a temperature of -40°C, even if a higher transport temperature is intended to be used. 3.3.2 The tanks shall be thermally stress relieved. Mechanical stress relief shall not be accepted as an equivalent.

3.4 Instrumentation, safety devices 3.4.1 The ship shall be provided with a chlorine absorbing plant with a connection to the cargo piping system and the cargo tanks. The absorbing plant shall be capable of neutralizing at least 2% of the total cargo capacity at a reasonable absorption rate. 3.4.2 During the gas-freeing of cargo tanks, vapours shall not be discharged to the atmosphere. 3.4.3 A gas detecting system shall be provided that is capable of monitoring chlorine concentrations of at least 1 ppm by volume. Sample points shall be located:

.1 .2 .3 .4

near the bottom of the hold spaces

.5

on deck – at the forward end, midships and the after end of the cargo area.

in the pipes from the safety relief valves at the outlet from the gas absorbing plant at the inlet to the ventilation systems for the accommodation, service and machinery spaces and control stations, and This is only required to be used during cargo handling and gas-freeing operations.

The gas detection system shall be provided with an audible and visual alarm with a set point of 5 ppm.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 193

Part 5 Chapter 7 Section 17

3.1.5 Outlets from PRVs shall be arranged in such a way as to minimize the hazards on board the ship as well as to the environment. Leakage from the relief valves shall be led through the absorption plant to reduce the gas concentration as far as possible. The relief valve exhaust line shall be arranged at the forward end of the ship to discharge outboard at deck level with an arrangement to select either port or starboard side, with a mechanical interlock to ensure that one line is always open.

3.5 Personnel protection The enclosed space required by [1.4.5] shall meet the following requirements:

.1

the space shall be easily and quickly accessible from the weather decks and from accommodation spaces by means of air locks and shall be capable of being rapidly closed gastight

.2

one of the decontamination showers required by Sec.14 [2.1.2] shall be located near the weather decks airlock to the space

.3

the space shall be so designed to accommodate the entire crew of the ship and be provided with a source of uncontaminated air for a period of not less than 4 hours, and

.4

one set of oxygen therapy equipment shall be carried in the space.

3.6 Filling limits for cargo tanks 3.6.1 The requirements of Sec.15 [1.1.3] .2 do not apply when the tank is intended to carry chlorine. 3.6.2 The chlorine content of the gas in the vapour space of the cargo tank after loading shall be greater than 80% by volume.

4 Ethylene oxide 4.1 General requirements 4.1.1 For the carriage of ethylene oxide the requirements of [8] shall apply, with the additions and modifications as given in this section. 4.1.2 Deck tanks shall not be used for the carriage of ethylene oxide. 4.1.3 Stainless steels types 416 and 442, as well as cast iron, shall not be used in ethylene oxide cargo containment and piping systems. 4.1.4 Before loading, tanks shall be thoroughly and effectively cleaned to remove all traces of previous cargoes from tanks and associated pipework, except where the immediate prior cargo has been ethylene oxide, propylene oxide or mixtures of these products. Particular care shall be taken in the case of ammonia in tanks made of steel other than stainless steel. 4.1.5 Ethylene oxide shall be discharged only by deepwell pumps or inert gas displacement. The arrangement of pumps shall comply with [8.1.15]. 4.1.6 Ethylene oxide shall be carried refrigerated only and maintained at temperatures of less than 30°C. 4.1.7 PRVs shall be set at a pressure of not less than 0.55 MPa. The maximum set pressure shall be specially approved by the Society. 4.1.8 The protective padding of nitrogen gas, as required by [8.1.27], shall be such that the nitrogen concentration in the vapour space of the cargo tank will at no time be less than 45% by volume. 4.1.9 Before loading, and at all times when the cargo tank contains ethylene oxide liquid or vapour, the cargo tank shall be inerted with nitrogen.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 194

Part 5 Chapter 7 Section 17

3.4.4 Each cargo tank shall be fitted with a high-pressure alarm giving an audible alarm at a pressure equal to 1.05 MPa.

4.1.11 A jettisoning arrangement shall be provided to allow the emergency discharge of ethylene oxide in the event of uncontrollable self-reaction.

5 Separate piping systems 5.1 General 5.1.1 Separate piping systems, as defined in Sec.1 [3.1] shall be provided.

6 Methyl acetylene-propadiene mixtures 6.1 General requirements 6.1.1 Methyl acetylene-propadiene mixtures shall be suitably stabilized for transport. Additionally, upper limits of temperatures and pressure during the refrigeration shall be specified for the mixtures. 6.1.2 Examples of acceptable, stabilized compositions are:

.1

.2

composition 1

.1 .2 .3

maximum methyl acetylene to propadiene molar ratio of 3 to 1

.4

maximum combined concentration of propylene and butadiene of 10 mol %

maximum combined concentration of methyl acetylene and propadiene of 65 mol % minimum combined concentration of propane, butane, and isobutane of 24 mol %, of which at least one third (on a molar basis) shall be butanes and one third propane

composition 2

.1 .2 .3 .4 .5 .6

maximum methyl acetylene and propadiene combined concentration of 30 mol % maximum methyl acetylene concentration of 20 mol % maximum propadiene concentration of 20 mol % maximum propylene concentration of 45 mol % maximum butadiene and butylenes combined concentration of 2 mol % minimum saturated C4 hydrocarbon concentration of 4 mol % and

.7

minimum propane concentration of 25 mol %.

6.1.3 Other compositions may be accepted provided the stability of the mixture is demonstrated to the satisfaction of the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 195

Part 5 Chapter 7 Section 17

4.1.10 The water-spray system required by [8.1.29] and that are required by Sec.11 [3] shall operate automatically in a fire involving the cargo containment system.

.1

a vapour compressor that does not raise the temperature and pressure of the vapour above 60°C and 1.75 MPa during its operation, and that does not allow vapour to stagnate in the compressor while it continues to run

.2

discharge piping from each compressor stage or each cylinder in the same stage of a reciprocating compressor shall have:

.1 .2 .3

two temperature-actuated shutdown switches set to operate at 60°C or less a pressure-actuated shutdown switch set to operate at 1.75 MPa bar gauge or less a safety relief valve set to relieve at 1.8 MPa bar gauge or less.

.3

the relief valve required by .2 and .3 shall vent to a mast meeting the requirements of Sec.8 [2.2.7], Sec.8 [2.2.8] and Sec.8 [2.2.13] and shall not relieve into the compressor suction line, and

.4

an alarm that sounds in the cargo control position and in the navigating bridge when a high-pressure switch, or a high-temperature switch, operates.

6.1.5 The piping system, including the cargo refrigeration system, for tanks to be loaded with methyl acetylene-propadiene mixtures shall be either independent, as defined in Sec.1 [3.1], or separate, as defined in Sec.1 [3.1], from piping and refrigeration systems for other tanks. This segregation shall apply to all liquid and vapour vent lines and any other possible connections, such as common inert gas supply lines.

7 Nitrogen 7.1 General requirements 7.1.1 Materials of construction and ancillary equipment such as insulation shall be resistant to the effects of high oxygen concentrations caused by condensation and enrichment at the low temperatures attained in parts of the cargo system. Due consideration shall be given to ventilation in such areas, where condensation might occur, to avoid the stratification of oxygen-enriched atmosphere.

8 Propylene oxide and mixtures of ethylene oxide-propylene oxide with ethylene oxide content of not more than 30% by weight 8.1 General requirements 8.1.1 Products transported under the provisions of this section shall be acetylene-free. 8.1.2 Unless cargo tanks are properly cleaned, these products shall not be carried in tanks that have contained as one of the three previous cargoes any product known to catalyse polymerization, such as:

.1 .2 .3

anhydrous ammonia and ammonia solutions amines and amine solutions, and oxidizing substances (e.g. chlorine).

8.1.3 Before loading, tanks shall be thoroughly and effectively cleaned to remove all traces of previous cargoes from tanks and associated pipework, except where the immediate prior cargo has been propylene

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 196

Part 5 Chapter 7 Section 17

6.1.4 If a ship has a direct vapour compression refrigeration system, this shall comply with the following requirements, subject to pressure and temperature limitations depending on the composition. For the example, the compositions given in [6.1.2], the following features shall be provided:

8.1.4 In all cases, the effectiveness of cleaning procedures for tanks and associated pipework shall be checked, by suitable testing or inspection, to ascertain that no traces of acidic or alkaline materials remain that might create a hazardous situation in the presence of these products. 8.1.5 Tanks shall be entered and inspected prior to each initial loading of these products to ensure freedom from contamination, heavy rust deposits and any visible structural defects. When cargo tanks are in continuous service for these products, such inspections shall be performed at intervals of not more than two years. 8.1.6 Tanks for the carriage of these products shall be of steel or stainless steel construction. 8.1.7 Tanks that have contained these products may be used for other cargoes after thorough cleaning of tanks and associated pipework systems by washing or purging. 8.1.8 All valves, flanges, fittings and accessory equipment shall be of a type suitable for use with these products and shall be constructed of steel or stainless steel in accordance with recognized standards. Disc or disc faces, seats and other wearing parts of valves shall be made of stainless steel containing not less than 11% chromium. 8.1.9 Gaskets shall be constructed of materials which do not react with, dissolve in, or lower the autoignition temperature of these products and which are fire-resistant and possess adequate mechanical behaviour. The surface presented to the cargo shall be polytetrafluoroethylene (PTFE) or materials giving a similar degree of safety by their inertness. Spirally-wound stainless steel with a filler of PTFE or similar fluorinated polymer may be accepted if approved by the Society. 8.1.10 Insulation and packing if used shall be of a material which does not react with, dissolve in, or lower the auto-ignition temperature of these products. 8.1.11 The following materials are generally found unsatisfactory for use in gaskets, packing and similar uses in containment systems for these products and would require testing before being approved:

.1 .2 .3

neoprene or natural rubber it if comes into contact with the products asbestos or binders used with asbestos, and materials containing oxides of magnesium, such as mineral wools.

8.1.12 Filling and discharge piping shall extend to within 100 mm of the bottom of the tank or any sump. 8.1.13 The products shall be loaded and discharged in such a manner that venting of the tanks to atmosphere does not occur. If vapour return to shore is used during tank loading, the vapour return system connected to a containment system for the product shall be independent of all other containment systems. 8.1.14 During discharging operations, the pressure in the cargo tank shall be maintained above 0.007 MPa. 8.1.15 The cargo shall be discharged only by deepwell pumps, hydraulically operated submerged pumps, or inert gas displacement. Each cargo pump shall be arranged to ensure that the product does not heat significantly if the discharge line from the pump is shut off or otherwise blocked. 8.1.16 Tanks carrying these products shall be vented independently of tanks carrying other products. Facilities shall be provided for sampling the tank contents without opening the tank to atmosphere. 8.1.17 Cargo hoses used for transfer of these products shall be marked FOR ALKYLENE OXIDE TRANSFER ONLY.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 197

Part 5 Chapter 7 Section 17

oxide or ethylene oxide-propylene oxide mixtures. Particular care shall be taken in the case of ammonia in tanks made of steel other than stainless steel.

8.1.19 Prior to disconnecting shore lines, the pressure in liquid and vapour lines shall be relieved through suitable valves installed at the loading header. Liquid and vapour from these lines shall not be discharged to atmosphere. 8.1.20 Tanks shall be designed for the maximum pressure expected to be encountered during loading, carriage or unloading of cargo. 8.1.21 Tanks for the carriage of propylene oxide with a design vapour pressure of less than 0.06 MPa, and tanks for the carriage of ethylene oxide-propylene oxide mixtures with a design vapour pressure of less than 0.12 MPa, shall have a cooling system to maintain the cargo below the reference temperature. For reference temperatures see Sec.15 [1.1.3]. 8.1.22 Pressure relief valve settings shall not be less than 0.02 MPa; for type C independent cargo tanks not greater than 0.7 MPa for the carriage of propylene oxide and not greater than 0.53 MPa for the carriage of ethylene oxide-propylene oxide mixtures. 8.1.23 The piping system for tanks to be loaded with these products shall be completely separate from piping systems for all other tanks, including empty tanks, and from all cargo compressors. If the piping system for the tanks to be loaded with these products is not independent, as defined in Sec.1 [3.1], the required piping separation shall be accomplished by the removal of spool pieces, valves, or other pipe sections and the installation of blank flanges at these locations. The required separation applies to all liquid and vapour piping, liquid and vapour vent lines and any other possible connections such as common inert gas supply lines. 8.1.24 The products shall be transported only in accordance with cargo handling plans approved by the Society. Each intended loading arrangement shall be shown on a separate cargo handling plan. Cargo handling plans shall show the entire cargo piping system and the locations for installation of the blank flanges needed to meet the above piping separation requirements. A copy of each approved cargo handling plan shall be kept on board the ship. 8.1.25 Before each initial loading of these products, and before every subsequent return to such service, certification verifying that the required piping separation has been achieved, shall be obtained from a responsible person acceptable to the port administration. Such certification shall carried on board the ship. Each connection between a blank flange and pipeline flange shall be fitted with a wire and seal by the responsible person to ensure that inadvertent removal of the blank flange is impossible. 8.1.26 The maximum allowable loading limits for each tank shall be indicated for each loading temperature that may be applied, in accordance with Sec.15 [1.5]. 8.1.27 The cargo shall be carried under a suitable protective padding of nitrogen gas. An automatic nitrogen make-up system shall be installed to prevent the tank pressure falling below 0.07 MPa in the event of product temperature fall due to ambient conditions or malfunctioning of refrigeration system. Sufficient nitrogen shall be available on board to satisfy the demand of the automatic pressure control. Nitrogen of commercially pure quality, i.e. 99.9% by volume, shall be used for padding. A battery of nitrogen bottles, connected to the cargo tanks through a pressure reduction valve, satisfies the intention of the expression automatic in this context. 8.1.28 The cargo tank vapour space shall be tested prior to and after loading to ensure that the oxygen content is 2% by volume or less. 8.1.29 A water spray system of sufficient capacity shall be provided to blanket effectively the area surrounding the loading manifold, the exposed deck piping associated with product handling and the tank

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 198

Part 5 Chapter 7 Section 17

8.1.18 Hold spaces shall be monitored for these products. Hold spaces surrounding type A and B independent tanks shall also be inerted and monitored for oxygen. The oxygen content of these spaces shall be maintained below 2% by volume. Portable sampling equipment is satisfactory.

8.1.30 The water spray system shall be capable of local and remote manual operation in case of a fire involving the cargo containment system. Remote manual operation shall be arranged such that the remote starting of pumps supplying the water spray system and remote operation of any normally closed valves in the system can be carried out from a suitable location outside the cargo area, adjacent to the accommodation spaces and readily accessible and operable in the event of fire in the areas protected. 8.1.31 When ambient temperatures permit, a pressurized water hose ready for immediate use shall be available during loading and unloading operations, in addition to the water spray requirements above.

9 Vinyl chloride 9.1 General requirements 9.1.1 In cases where polymerization of vinyl chloride is prevented by addition of an inhibitor, [1.7] is applicable. In cases where no inhibitor has been added, or the inhibitor concentration is insufficient, any inert gas used for the purposes of [1.5] shall contain no more oxygen than 0.1% by volume. Before loading is started, inert gas samples from the tanks and piping shall be analysed. When vinyl chloride is carried, a positive pressure shall always be maintained in the tanks and during ballast voyages between successive carriages.

10 Mixed C4 cargoes 10.1 General requirements 10.1.1 Cargoes that may be carried individually under the requirement of this chapter, notably butane, butylenes and butadiene, may be carried as mixtures subject to the provisions of this section. These cargoes may variously be referred to as crude C4, crude butadiene, crude steam-cracked C4, spent steam-cracked C4, C4 stream, C4 raffinate, or may be shipped under a different description. In all cases, the material data sheets (MSDS) shall be consulted as the butadiene content of the mixture is of prime concern as it is potentially toxic and reactive. While it is recognized that butadiene has a relatively low vapour pressure, if such mixtures contain butadiene they shall be regarded as toxic and the appropriate precautions applied. 10.1.2 If the mixed C4 cargo shipped under the terms of this section contains more than 50% in mole of butadiene, the inhibitor precautions in [1.7] shall apply. 10.1.3 Unless specific data on liquid expansion coefficients is given for the specific mixture loaded, the filling limit restrictions of Sec.15 shall be calculated as if the cargo contained 100% concentration of the component with the highest expansion ratio.

11 Carbon dioxide 11.1 Carbon dioxide – high purity 11.1.1 Uncontrolled pressure loss from the cargo can cause sublimation and the cargo will change from the liquid to the solid state. The precise triple point temperature of a particular carbon dioxide cargo shall be supplied before loading the cargo, and will depend on the purity of that cargo, and this shall be taken into account when cargo instrumentation is adjusted. The set pressure for the alarms and automatic actions

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 199

Part 5 Chapter 7 Section 17

2

domes. The arrangement of piping and nozzles shall be such as to give a uniform distribution rate of 10 l/m per minute. The arrangement shall ensure that any spilled cargo is washed away.

11.1.2 There is a potential for the cargo to solidify in the event that a cargo tank relief valve, fitted in accordance with Sec.8 [2], fails in the open position. To avoid this, a means of isolating the cargo tank safety valves shall be provided and the requirements of Sec.8 [2.2.6] do not apply when carrying this carbon dioxide. Discharge piping from safety relief valves shall be designed so they remain free from obstructions that could cause clogging. Protective screens shall not be fitted to the outlets of relief valve discharge piping, so the requirements of Sec.8 [2.2.13] do not apply. Normally each cargo tank shall be provided with four safety relief valves. Means of easy isolation of each safety relief valve shall be fitted. Two valves shall always be in operation. 11.1.3 Discharge piping from safety relief valves are not required to comply with Sec.8 [2.2.7], but shall be designed so they remain free from obstructions that could cause clogging. Protective screens shall not be fitted to the outlets of relief valve discharge piping, so the requirements of Sec.8 [2.2.13] do not apply. 11.1.4 Cargo tanks shall be continuously monitored for low pressure when a carbon dioxide cargo is carried. An audible and visual alarm shall be given at the cargo control position and on the bridge. If the cargo tank pressure continues to fall to within 0.05 MPa of the triple point for the particular cargo, the monitoring system shall automatically close all cargo manifold liquid and vapour valves and stop all cargo compressors and cargo pumps. The emergency shutdown system required by Sec.8 [2] may be used for this purpose. 11.1.5 All materials used in cargo tanks and cargo piping system shall be suitable for the lowest temperature that may occur in service, which is defined as the saturation temperature of the carbon dioxide cargo at the set pressure of the automatic safety system described in [11.1.1]. 11.1.6 Cargo hold spaces, cargo compressor rooms and other enclosed spaces where carbon dioxide could accumulate, shall be fitted with continuous monitoring for carbon dioxide build-up. This fixed gas detection system replaces the requirements of Sec.13 [6], and hold spaces shall be monitored permanently even if the ship has type C cargo containment. 11.1.7 Hold spaces shall be segregated from machinery, boiler spaces and accommodation spaces by at least A-0 class. 11.1.8 Oxygen deficiency monitoring shall be fitted for cargo compressor rooms and cargo hold spaces. Audible and visual alarm shall be located on the navigation bridge, in the cargo control room, the engine control room and the cargo compressor room. 11.1.9 Cargo compressor rooms shall be mechanically ventilated by 30 air changes per hour. 11.1.10 Entrances to hold spaces containing cargo tanks and compressor rooms should be preferably from open deck. Direct access from accommodation spaces, service spaces and control stations is not accepted. In case the entrance is from any enclosed space other than the spaces specified above shall have audible and visual alarm for oxygen deficiency of the hold spaces and the compressor rooms. The access door shall be open outwards.

11.2 Carbon dioxide – reclaimed quality 11.2.1 The requirements of [11.1] also apply to this cargo. In addition, the materials of construction used in the cargo system shall also take account of the possibility of corrosion in case the reclaimed quality carbon dioxide cargo contains impurities such as water, sulphur dioxide, etc., which can cause acidic corrosion or other problems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 200

Part 5 Chapter 7 Section 17

described in this section shall be set to at least 0.05 MPa above the triple point for the specific cargo being carried. The triple point for pure carbon dioxide occurs at 0.5 MPa and -54.4°C.

1 Cargo operations manuals 1.1 General requirements 1.1.1 The ship shall be provided with copies of suitably detailed cargo system operating manuals approved by the Society such that trained personnel can safely operate the vessel with due regard to the hazards and properties of the cargoes that are permitted to be carried. 1.1.2 The content of the manuals shall include but not be limited to:

.1

overall operation of the ship from dry-dock to dry-dock, including procedures for cargo tank cooldown and warm-up, transfer including ship-to-ship transfer, cargo sampling, gas-freeing, ballasting, tank cleaning and changing cargoes

.2 .3

cargo temperature and pressure control systems

.4 .5

nitrogen and inert gas systems

.6 .7 .8 .9 .10

special equipment needed for the safe handling of the particular cargo

.11

emergency procedures, including cargo tank relief valve isolation, single tank gas-freeing and entry and emergency ship-to-ship transfer operations.

cargo system limitations, including minimum temperatures in cargo system and inner hull, maximum pressures, transfer rates, filling limits and sloshing limitations fire-fighting procedures: operation and maintenance of firefighting systems and use of extinguishing agents fixed and portable gas detection control, alarm and safety systems emergency shutdown systems procedures to change cargo tank pressure relief valve set pressures in accordance with Sec.8 [2.2.5] and Sec.4 [3.3.1].3, and

1.2 Cargo information 1.2.1 Information shall be on board and available to all concerned, in the form of a cargo information data sheet(s) giving the necessary data for the safe carriage of cargo. Such information shall include, for each product carried:

.1

a full description of the physical and chemical properties necessary for the safe carriage and containment of the cargo

.2

reactivity with other cargoes that are capable of being carried on board in accordance with the certificate of fitness

.3 .4 .5 .6 .7

the actions to be taken in the event of cargo spills or leaks countermeasures against accidental personal contact fire-fighting procedures and fire-fighting media special equipment needed for the safe handling of the particular cargo; and emergency procedures.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 201

Part 5 Chapter 7 Section 18

SECTION 18 CARGO OPERATION MANUAL AND CARGO EMERGENCY SHUTDOWN SYSTEM

1.2.3 Contingency plans in accordance with [1.2.1].3, for spillage of cargo carried at ambient temperature, shall take account of potential local temperature reduction such as when the escaped cargo has reduced to atmospheric pressure and the potential effect of this cooling on hull steel.

2 Cargo emergency shutdown (ESD) system 2.1 General 2.1.1 A cargo emergency shutdown system shall be fitted to all ships to stop cargo flow in the event of an emergency, either internally within the ship, or during cargo transfer with ship or shore. The design of the ESD system shall avoid the potential generation of surge pressures within cargo transfer pipe work, see [2.1.4]. 2.1.2 Auxiliary systems for conditioning the cargo that use toxic or flammable liquids or vapours shall be treated as cargo systems for the purposes of ESD. Indirect refrigeration systems using an inert medium, such as nitrogen, need not be included in the ESD function. 2.1.3 The ESD system shall be activated by the manual and automatic inputs listed in Table 1. Any additional inputs shall only be included in the ESD system if it can be shown their inclusion does not reduce the integrity and reliability of the system overall. 2.1.4 Ship's ESD systems shall incorporate a ship-shore link. 2.1.5 A functional flow chart of the ESD system and related systems shall be provided in the cargo control station and on the navigation bridge.

2.2 ESD valve requirements 2.2.1 The term ESD valve means any valve operated by the ESD system. 2.2.2 ESD valves shall be remotely operated, be of the fail closed type (closed on loss of actuating power), shall be capable of local manual closure and have positive indication of the actual valve position. As an alternative to the local manual closing of the ESD valve, a manually operated shut-off valve in series with the ESD valve shall be permitted. The manual valve shall be located adjacent to the ESD valve. Provisions shall be made to handle trapped liquid shall the ESD valve close while the manual valve is also closed. 2.2.3 ESD valves in liquid piping systems shall close fully and smoothly within 30 seconds of actuation. Information about the closure time of the valves and their operating characteristics shall be available on board, and the closing time shall be verifiable and repeatable. Guidance note: Emergency shutdown valves in liquid piping shall fully close under all service conditions within 30 s of actuation as measured from the time of manual or automatic initiation to full closure. This is called the total shut-down time and is made up of a signal response time and a valve closure time. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 202

Part 5 Chapter 7 Section 18

1.2.2 The physical data supplied to the master, in accordance with [1.2.1], shall include information regarding the relative cargo density at various temperatures to enable the calculation of cargo tank filling limits in accordance with the requirements of Sec.15.

where:

U = ullage volume at operating signal level in m3 LR = maximum loading rate agreed between ship and shore facility in m3/h. The loading rate shall be adjusted to limit surge pressure on valve closure to an acceptable level, taking into account the loading hose or arm, the ship and the shore piping systems where relevant. 2.2.5 Ship-shore and ship-ship manifold connections One ESD valve shall be provided at each manifold connection. Cargo manifold connections not being used for transfer operations shall be blanked with blank flanges rated for the design pressure of the pipeline system. 2.2.6 Cargo system valves If cargo system valves as defined in Sec.5 [5] are also ESD valves within the meaning of this sub-section, then the requirements of this sub-section shall apply.

2.3 ESD system controls 2.3.1 As a minimum, the ESD system shall be capable of manual operation by a single control on the bridge and either in the control position required by Sec.13 [1.1.2] or the cargo control room if installed, and no less than two locations in the cargo area. Guidance note: The ESD system should be arranged for release from at least one position forward of and at least one position aft the cargo area, and from an appropriate number of positions within the cargo area, dependent on the size of the ship. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.3.2 The ESD shall be automatically activated on detection of a fire on the weather decks of the cargo area and/or cargo machinery spaces. As a minimum, the method of detection used on the weather decks shall cover the liquid and vapour domes of the cargo tanks, the cargo manifolds and areas where liquid piping is dismantled regularly. Detection may be by means of fusible elements designed to melt at temperatures between 98°C and 104°C, or by area fire detection methods. 2.3.3 Cargo machinery that is running shall be stopped by activation of the ESD system in accordance with the cause and effect matrix in Table 1. 2.3.4 The ESD control system shall be configured so as to enable the high-level testing required in Sec.13 [3.1.5] to be carried out in a safe and controlled manner. For the purpose of the testing, cargo pumps may be operated while the overflow control system is overridden. Procedures for level alarm testing and re-setting of the ESD system after completion of the high-level alarm testing shall be included in the operation manual required by [1.1.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 203

Part 5 Chapter 7 Section 18

2.2.4 The closing time of the valve in seconds referred to in Sec.13 [3.1.1] to Sec.13 [3.1.3], i.e. time from shutdown signal initiation to complete valve closure, shall not be greater than:

Re-liquefaction plant*** including condensate return pumps, if fitted

Gas combustion unit

ESD valves

Signal to ship/shore link****

Link

Fuel gas compressors

Valves

Vapour return compressors

Compressor Systems

Spray/stripping pumps

Pumps

Cargo pumps/ cargo booster pumps

Shutdown action

X

X

X

2)

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

1) and 2)

1) and 3)

1)

6)

X

X

X

X

2)

3)

N/A

X

N/A

Loss of motive power to ESD valves**

X

X

X

2)

3)

N/A

X

X

Main electric power failure (blackout)

7)

7)

7)

7)

7)

7)

X

X

Level alarm override, see Sec.13 [3.1.7]

4)

4) and 5)

X

1)

1)

1)

X

X

Initiation

Emergency push buttons, see [2.3.1] Fire detection on deck or in compressor house*, see [2.3.2] High level in cargo tank, see Sec.13 [3.1.2] Signal from ship/shore link, see [2.1.4]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 204

Part 5 Chapter 7 Section 18

Table 1 ESD functional arrangements

ESD valves

1)

These items of equipment can be omitted from these specific automatic shutdown initiators provided the compressor inlets are protected against cargo liquid ingress.

2)

If the fuel gas compressor is used to return cargo vapour to shore, it shall be included in the ESD system only when operating in this mode.

3)

If the reliquefaction plant compressors are used for vapour return/shore line clearing, they shall be included in the ESD system only when operating in that mode.

4)

The override system permitted by Sec.13 [3.1.7] may be used at sea to prevent false alarms or shutdowns. When level alarms are overridden, cargo pumps and manifold valves shall be inhibited except when high-level alarm testing carried out in accordance with [2.3.4].

5)

Cargo spray or stripping pumps used to supply forcing vaporizer may be excluded from the ESD system only when operating in that mode.

6)

The sensors referred to in Sec.13 [3.1.2] may be used to close automatically the tank filling valve for the individual tank where the sensors are installed, as an alternative to closing the ESD valve referred to in [2.2.5] If this option is adopted, activation of the full ESD system shall be initiated when the high-level sensors in all the tanks to be loaded have been activated.

7)

These items of equipment shall not be started automatically upon recovery of main electric power and without confirmation of safe conditions.

Remarks:

*

Fusible plugs, electronic point temperature monitoring or area fire detection may be used for this purpose on deck.

** ***

Failure of hydraulic, electric or pneumatic power for remotely operated ESD valve actuators.

**** X N/A

Signal need not indicate the event initiating ESD.

Indirect refrigeration systems using an inert medium, such as nitrogen, need not be included in the ESD function. Function requirement. Not applicable.

2.4 Additional shutdowns 2.4.1 The requirements of Sec.8 [3.1.1].1] to protect the cargo tank from external differential pressure may be fulfilled by using an independent low pressure trip to activate the ESD system, or as minimum to stop any cargo pumps or compressors.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 205

Part 5 Chapter 7 Section 18

Link Signal to ship/shore link****

Valves

Gas combustion unit

Re-liquefaction plant*** including condensate return pumps, if fitted

Fuel gas compressors

Vapour return compressors

Compressor Systems

Spray/stripping pumps

Initiation

Pumps

Cargo pumps/ cargo booster pumps

Shutdown action

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 206

Part 5 Chapter 7 Section 18

2.4.2 An input to the ESD system from the overflow control system required by Sec.13 [3] may be provided to stop any cargo pumps or compressors' running at the time a high level is detected, as this alarm may be due to inadvertent internal transfer of cargo from tank to tank.

1 General 1.1 Explanatory notes to the summary of minimum requirements Minimum requirements for each product are as described in Table 2. Table 1 Description of items in Table 2 Item

Column in Table 2

Description

Product name

a

The product name shall be used in the shipping document for any cargo offered for bulk shipments. Any additional name may be included in brackets after the product name. In some cases, the product names are not identical with the names given in previous issues of the rule set.

Lquid density

b

Applicable density for guidance.

Ship type

c

1: ship type 1G, see Sec.2 [1.1.2] .1. 2: ship type 2G, see Sec.2 [1.1.2] .2. 3: ship type 2PG, see Sec.2 [1.1.2] .3. 4: ship type 3G, see Sec.2 [1.1.2] .4.

Independent tank type C required

d

type C independent tank, see Sec.22 [1.1.2].

Tank environmental control

e

inert: inerting, see Sec.9 [1.4]. dry: drying, see Sec.17 [1.6]. - : no special requirements under this chapter.

Vapour detection

f

F: flammable vapour detection. T: toxic vapour detection. F+T: flammable and toxic vapour detection. A: asphyxiating.

Gauging

g

I: indirect or closed, see Sec.13 [2.1.3] .1 and .2. R: indirect, closed or restricted, see Sec.13 [2.1.3]. C: indirect or closed, see Sec.13 [2.1.3] .1, .2, and .3.

Special requirements

i

When specific reference is made to Sec.14 and/or Sec.17, these requirements shall be additional to the requirements in any other column.

Refrigerant gases

-

Non-toxic and non-flammable gases.

Unless otherwise specified, gas mixtures containing less than 5% total acetylene may be transported with no further requirements than those provided for the major components.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 207

Part 5 Chapter 7 Section 19

SECTION 19 SUMMARY OF MINIMUM REQUIREMENTS

g

i

Product name

Gauging

f

Vapour detection

e

Control of vapour space within cargo tanks

d

Independent tank type C required

c

Ship type

b Liquid density 3 in kg/m and (Temp.) at atm

a

Special requirements

780 (20.8°C)

2G/2PG

-

inert

F+T

C

Sec.14 [1.3.3] .1, Sec.14 [2.1.2], Sec.17 [1.3.1], Sec.17 [1.5] .1

ammonia, anhydrous

680 (–33.4°C)

2G/2PG

-

-

T

C

Sec.14 [2], Sec.17 [1.1.1].1, Sec.17 [2]

butadiene (all isomers)

650 (- 4.5°C)

2G/2PG

-

-

F+T

C

Sec.14 [2], Sec.17 [1.1.1] .2, Sec.17 [1.3.2], Sec.17 [1.3.3], Sec.17 [1.5], Sec.17 [1.7]

butane (all isomers)

600 (–0.5°C)

2G/2PG

-

-

F

R

-

2G/2PG

-

-

F

R

630 to 640 (–6.3 to 3.7°C)

2G/2PG

-

-

F

R

-

3G

-

-

A

R

Sec.17 [11.1]

-

3G

-

-

A

R

Sec.17 [11.2]

I

Sec.14 Sec.17 Sec.17 Sec.17

[2], Sec.17 [1.2.2], [1.3.1], Sec.17 [1.4], [1.6], Sec.17 [1.8], [3] [2.1.1], Sec.14 [2.1.2], [1.1.1] .6, Sec.17 [1.2.1], [1.5] .1, Sec.17 [1.8], [1.9], Sec.17 [1.10.2], [1.10.3]

acetaldehyde

butane-propane mixture butylenes (all isomers) carbon dioxide (high purity) carbon dioxide (reclaimed quality)

chlorine

1 560 (–34°C)

1G

yes

dry

T

diethyl ether*

640 (34.6°C)

2G/2PG

-

inert

F+T

C

Sec.14 Sec.17 Sec.17 Sec.17 Sec.17

dimethylamine

670 (6.9°C)

2G/2PG

-

-

F+T

C

Sec.14 [2], Sec.17 [1.1.1] .1

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 208

Part 5 Chapter 7 Section 19

Table 2 Summary of minimum requirements

d

e

f

g

i

Product name

Independent tank type C required

Control of vapour space within cargo tanks

Special requirements

2G/2PG

ethane

550 (–88°C)

2G

-

ethyl chloride

920 (12.4°C)

2G/2PG

ethylene

560 (-104°C)

2G

ethylene oxide

870 (10.4°C)

ethylene oxidepropylene oxide mixtures with ethylene oxide content of not

1G

Gauging

668 (–23°C)

Vapour detection

dimethyl ether

F

R

-

F

R

-

-

F +T

C

-

-

F

R

yes

inert

F +T

Sec.17 [8.1.9], Sec.17 [8.1.11]

C

Sec.14 Sec.17 Sec.17 Sec.17

[2], Sec.17 [1.1.1] .2, [1.2.1], Sec.17 [1.3.1], [1.4], Sec.17 [1.5] .1, [4] .1, Sec.17 [4] [2.1.2], Sec.17 [1.2.1], [1.3.1], [1.5] .1, Sec.17 [1.8], [1.9], Sec.17 [8]

-

2G/2PG

-

inert

F +T

C

Sec.14 Sec.17 Sec.17 Sec.17

isoprene*, all isomers

680 (34°C)

2G/2PG

-

-

F

R

Sec.14 [2.1.2], Sec.17 [1.7], Sec.17 [1.8], Sec.17 [1.10.3]

isoprene*, part refined

-

2G/2PG

-

-

F

R

Sec.14 [2.1.2], Sec.17 [1.7], Sec.17 [1.8], Sec.17 [1.10.3] Sec.14 Sec.17 Sec.17 Sec.17

more than 30% by weight*

isopropylamine*

710 (33°C)

2G/2PG

-

-

F+ T

C

methane (LNG)

420 (–164°C)

2G

-

-

F

C

-

2G/2PG

-

-

F

R

methyl acetylenepropadiene mixtures

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

[2.1.1], Sec.14 [2.1.2], [1.1.1].4, Sec.17 [1.8], [1.9], Sec.17 [1.10.1], [1.4]

Sec.17 [6]

Page 209

Part 5 Chapter 7 Section 19

c

Ship type

b Liquid density 3 in kg/m and (Temp.) at atm

a

i

Product name

Special requirements

methyl bromide

1 730

1G

yes

-

F+T

C

Sec.14 [2], Sec.17 [1.1.1] .3, Sec.17 [1.2.2], Sec.17 [1.3.1], Sec.17 [1.4]

methyl chloride

920

2G/ 2PG

-

-

F+T

C

Sec.17 [1.1.1] .3

C

Sec.14 Sec.17 Sec.17 Sec.17

[2], Sec.17 [1.1.1] .2, [1.3.2], Sec.17 [1.3.3], [1.5], Sec.17 [1.7], [10] [2], Sec.17 [1.1.1] .1, [1.2.1], Sec.17 [1.8], [1.9], Sec.17 [1.10.1], [5]

mixed C4 cargoes

-

2G/2PG

-

-

F+T

monoethylamine*

690 (16.6°C)

2G/2PG

-

-

F+T

C

Sec.14 Sec.17 Sec.17 Sec.17

nitrogen

808 (–196°C)

3G

-

-

A

C

Sec.17 [1.6]

pentane*, all isomers

630

2G/2PG

-

-

F

R

Sec.17 [1.8], Sec.17 [1.10]

pentene*, all isomers

650

2G/2PG

-

-

F

R

Sec.17 [1.8], Sec.17 [1.10]

propane

590 (–42.3°C)

2G/2PG

-

-

F

R

propylene

610 (–47.7°C)

2G/2PG

-

-

F

R

propylene oxide*

860

2G/2PG

-

inert

F+T

C

refrigerant gases

--

3G

-

-

-

R

1 460 (–10°C)

1G

yes

dry

T

C

sulphur dioxide

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Sec.14 [2.1.2], Sec.17 [1.2.1], Sec.17 [1.3.1], Sec.17 [1.5] .1, Sec.17 [1.8], Sec.17 [1.9], Sec.17 [8]

Sec.14 [2], Sec.17 [1.2.2], Sec.17 [1.3.1], Sec.17 [1.4], Sec.17 [1.6]

Page 210

Part 5 Chapter 7 Section 19

g

Gauging

f

Vapour detection

e

Control of vapour space within cargo tanks

d

Independent tank type C required

c

Ship type

b Liquid density 3 in kg/m and (Temp.) at atm

a

c

d

e

f

g

i

Product name

Liquid density 3 in kg/m and (Temp.) at atm

Ship type

Independent tank type C required

Control of vapour space within cargo tanks

Vapour detection

vinyl chloride

vinyl ethyl ether*

vinylidene chloride*

970 (–13.9°C)

754

1 250

2G/2PG

2G/2PG

2G/2PG

-

-

-

-

inert

inert

F+T

F+T

F+T

Special requirements

C

Sec.14 [2.1.1], Sec.14 [2.1.2], Sec.17 [1.1.1] .2, Sec.17 [1.1.1] .3, Sec.17 [1.2.1], Sec.17 [1.5], Sec.17 [9]

C

Sec.14 [2.1.1], Sec.14 [2.1.2], Sec.17 [1.1.1] .2, Sec.17 [1.2.1], Sec.17 [1.5] .1, Sec.17 [7], Sec.17 [1.8], Sec.17 [9], Sec.17 [1.10.2], Sec.17 [1.10.3]

C

Sec.14 [2.1.1], Sec.14 [2.1.2], Sec.17 [1.1.1] .5, Sec.17 [1.5] .1, Sec.17 [1.7], Sec.17 [1.8], Sec.17 [1.9]

* this cargo is also covered by the IBC code

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 211

Part 5 Chapter 7 Section 19

b

Gauging

a

1 Type-A tank 1.1 Design basis 1.1.1 Hull design The hull design shall be carried out according to main class requirements in Pt.3 of the rules. In addition, the present rules for liquefied gas carriers, this section gives additional design requirements for liquefied gas carriers with independent prismatic type A tanks. 1.1.2 Type A independent tanks are tanks primarily designed using ship-structural analysis procedures as given in Pt.3. Where such tanks are primarily constructed of plane surfaces, the design vapour pressure Po shall be less than 0.07 MPa. 1.1.3 If the cargo temperature at atmospheric pressure is below -10°C, a complete secondary barrier shall be provided as required in Sec.4 [2.3]. The secondary barrier shall be designed according to Sec.4 [2.4]. 1.1.4 If the cargo temperature at atmospheric pressure is at or above –55°C the hull may act as a secondary barrier based on the following: — the hull material shall be suitable for the cargo temperature at atmospheric pressure as required in Sec.4 [5.1.1] — the design shall be such that this temperature will not result in unacceptable hull stresses. With lower temperature a separate complete secondary barrier shall be arranged according to Sec.4 [2.4.2]. 1.1.5 Cargo design density For design the specific cargo density shall be taken as the highest density for the actual gas composition to be carried at the planned trades.

1.2 Structural analysis of cargo tanks 1.2.1 A structural analysis shall be performed taking into account the internal pressure as indicated in Sec.4 [3.3.2], and the interaction loads with the supporting and keying system as well as a reasonable part of the ship's hull. 1.2.2 For parts, such as supporting structures, not otherwise covered by the requirements of this section, stresses shall be determined by direct calculations, taking into account the loads referred to in Sec.4 [3.2] to Sec.4 [3.5] as far as applicable, and the ship deflection in way of supporting structures. 1.2.3 The tanks with supports shall be designed for the accidental loads specified in Sec.4 [3.5].IIt is not required to take into account combination of such loads with each other or with environmental loads. 1.2.4 Design conditions The effects of all dynamic and static loads shall be used to determine the suitability of the structure with respect to: — ultimate limit state design condition (ULS) — plastic deformation — buckling. — accident limit state design condition (ALS)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 212

Part 5 Chapter 7 Section 20

SECTION 20 DESIGN WITH INDEPENDENT PRISMATIC TANKS OF TYPE-A AND TYPE-B

1.2.5 Finite element analysis A three-dimensional analysis shall be carried out to evaluate the stress levels, including interaction with the ship's hull. The model for this analysis shall include the cargo tank with its supporting and keying system, as well as a reasonable part of the hull. 1.2.6 Thermal analysis and fatigue analysis o For conventional proven designs, and when the cargo temperature is not lower than -55 C, the following applies: — it is not required to perform stationary or transient thermal analyses — fatigue analysis of cargo tanks and supports may not be considered. o

For novel designs, and/or when the cargo temperature is below -55 C the following applies: — thermal analysis for material selection and thermal stress analysis shall be carried out — fatigue analyses of the cargo tanks and the supports shall be carried out with damage factor Cw ≤ 1.0, as specified in Pt.3 Ch.9 and DNVGL-CG-0129. Guidance note: Methods for strength analysis of hull structure and cargo tanks with prismatic Type-A tanks are given in DNVGL-CG-0133. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3 Ultimate design condition 1.3.1 For tanks primarily constructed of plane surfaces, the nominal membrane stresses for primary and secondary members (web frames, stringers, girders, stiffeners), when not calculated with FE analysis procedures, shall not exceed the lower of Rm /2.66 or ReH /1.33 for nickel steels, carbon-manganese steels, austenitic steels and aluminium alloys, where Rm and ReH are defined in Sec.4 [4.3.2].3. However, when finite element calculations are carried out for the primary members, the equivalent stress σvm, as defined in Sec.4 [4.3.2].4, may be increased to the level given in [4.3.4]. Calculations shall take into account the effects of bending, shear, axial and torsional deformation as well as the hull/cargo tank interaction forces due to the deflection of the double bottom and cargo tank bottoms. 1.3.2 Tank boundary scantlings shall meet at least the requirements of the Society for deep tanks taking into account the internal pressure as indicated in Sec.4 [3.3.2] and any corrosion allowance required by Sec.4 [2.1.5]. 1.3.3 The cargo tank structure shall be reviewed against potential buckling.

1.4 Accident design condition 1.4.1 The tanks and the tank supports shall be designed for the accidental loads and design conditions specified in Sec.4 [2.1.4].3 and Sec.4 [3.5], as relevant. 1.4.2 When subjected to the accidental loads specified in Sec.4 [3.5], the stress shall comply with the acceptance criteria specified in [1.3], modified as appropriate, taking into account their lower probability of occurrence.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 213

Part 5 Chapter 7 Section 20

— plastic deformation — buckling.

1.5.1 All type A independent tanks shall be subjected to a hydrostatic or hydropneumatic test. This test shall be performed such that the stresses approximate, as far as practicable, the design stresses, and that the pressure at the top of the tank corresponds at least to the MARVS. When a hydropneumatic test is performed, the conditions shall simulate, as far as practicable, the design loading of the tank and of its support structure, including dynamic components, while avoiding stress levels that could cause permanent deformation.

1.6 Special consideration for single side hull 1.6.1 Where the structural arrangement in cargo hold is similar to the single side skin bulk carrier as defined in Ch.1 Sec.6 [1.3.1], the following shall be considered. 1.6.2 Shear force correction For the hull structure with single side skin construction, the hull girder shear strength assessment shall be carried out in accordance with Pt.3 Ch.5 Sec.2 [2] with consideration of shear force correction given in Ch.1 Sec.5 [5.2.4] if applicable. Within the cargo hold region, shear force correction shall be applied to each loading condition given in the loading manual and the loading/unloading sequences. 1.6.3 Transverse frames in side shell 3 2 The net section modulus Z, in cm , and the net shear sectional area Ashr, in cm , of side frames subjected to lateral pressure shall not be less than the requirement in Ch.1 Sec.2 [5.2]. Permissible stress coefficient Cs and Ct are according to Pt.3 Ch.6 Sec.5. 1.6.4 Buckling strength of side shell plating When the buckling strength of side shell plating is assessed by closed form method (CFM) according to DNVGL-CG-0128 Sec.3, the factors, Ftran, and Cy for single side skin bulk carrier is applicable.

2 Type-B tank 2.1 Design basis 2.1.1 Hull design The hull design shall be carried out according to main class requirements in Pt.3. In addition, the present rules for liquefied gas carriers, this section give additional design requirements for liquefied gas carriers with independent prismatic type B tanks. 2.1.2 Type B independent tanks are tanks designed using model tests, refined analytical tools and analysis methods to determine stress levels, fatigue life and crack propagation characteristics. Where such tanks are primarily constructed of plane surfaces (prismatic tanks), the design vapour pressure Po shall be less than 0.07 MPa. 2.1.3 If the cargo temperature at atmospheric pressure is below -10°C, a partial secondary barrier with a small leak protection system shall be provided as required in Sec.4 [2.3]. The small leak protection system shall be designed according to Sec.4 [2.5], typically consisting of: — — — —

a gas detection system liquid containers to contain liquids spray shields to deflect liquids into the containers, and equipment to dispose of the liquid as required.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 214

Part 5 Chapter 7 Section 20

1.5 Testing

2.1.4 Cargo design density For design the specific cargo density shall be taken as the highest density for the actual gas composition to be carried at the planned trades.

2.2 Structural analysis of cargo tanks 2.2.1 Design conditions The effects of all dynamic and static loads shall be used to determine the suitability of the structure with respect to: — ultimate limit state design condition (ULS) — plastic deformation — buckling. — fatigue limit state design condition (FLS) — fatigue failure, and — crack propagation analysis. — accident limit state design condition (ALS) — plastic deformation — buckling. Finite element analysis and/or prescriptive requirements and fracture mechanics analysis shall be applied. Guidance note: Methods for strength analysis of hull structure and cargo tanks with prismatic B-type tanks are given in DNVGL-CG-0133. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.2 Finite element models A three-dimensional analysis shall be carried out to evaluate the stress levels, including interaction with the ship's hull. The model for this analysis shall include the cargo tank with its supporting and keying system, as well as a reasonable part of the hull. 2.2.3 Wave load analysis A complete analysis of the particular ship accelerations and motions in irregular waves, and of the response of the ship and its cargo tanks to these forces and motions shall be performed, unless the data is available from similar ships. 2.2.4 Fracture mechanics analyses Crack propagation analyses and design against brittle fracture shall be carried out according to recognized standards, e.g. BS7910. A fracture mechanics analysis according to Sec.4 [4.3.3].6 to 9 is required. 2.2.5 Fatigue testing Model tests may be required to determine stress concentration factors and fatigue life of structural elements.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 215

Part 5 Chapter 7 Section 20

This requires analyses and/or tests to document that the likelihood of massive leakages from the primary containment is reduced to an acceptable level, and to document the type and extent of potential leakages to be used for design and dimensioning the small leak protection system.

2.3.1 Plastic deformation For type B independent tanks, primarily constructed of plane surfaces, the allowable membrane equivalent stresses applied for finite element analysis shall not exceed:

.1 .2 .3

for nickel steels and carbon-manganese steels, the lesser of Rm/2 and ReH/1.2 for austenitic steels, the lesser of Rm/2.5 and ReH/1.2, and for aluminium alloys, the lesser of Rm/2.5 and ReH/1.2.

The above figures may be amended, taking into account the locality of the stress, stress analysis methods and design condition considered in acceptance with the Society. 2.3.2 Plates and stiffeners on boundary The thickness of the skin plate and the size of the stiffener shall not be less than those required for type A independent tanks. 2.3.3 Buckling Buckling strength analyses of cargo tanks subject to external pressure and other loads causing compressive stresses shall be carried out in accordance with Pt.3 Ch.8. The method shall adequately account for the difference in theoretical and actual buckling stress as a result of plate edge misalignment, lack of straightness or flatness, ovality and deviation from true circular form over a specified arc or chord length, as applicable. Reference is made to IACS Rec.47 Shipbuilding and Repair Quality Standard.

2.4 Fatigue design condition 2.4.1 Fatigue and crack propagation assessment shall be performed in accordance with Sec.4 [4.3.3]. The acceptance criteria shall comply with Sec.4 [4.3.3].7, Sec.4 [4.3.3].8 or Sec.4 [4.3.3].9, depending on the detectability of the defect. 2.4.2 Fatigue analysis shall consider construction tolerances. 2.4.3 Where deemed necessary by the Society, model tests may be required to determine stress concentration factors and fatigue life of structural elements.

2.5 Accident design condition 2.5.1 The tanks and the tank supports shall be designed for the accidental loads and design conditions specified in Sec.4 [2.1.4].3 and Sec.4 [3.5], as applicable. 2.5.2 When subjected to the accidental loads specified in Sec.4 [3.5], the stress shall comply with the acceptance criteria specified in [2.3], modified as appropriate, taking into account their lower probability of occurrence.

2.6 Testing 2.6.1 Type B independent tanks shall be subjected to a hydrostatic or hydropneumatic test as follows:

.1

the test shall be performed as required in [1.5.1] for type A independent tanks, and

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 216

Part 5 Chapter 7 Section 20

2.3 Ultimate design condition

in addition, the maximum primary membrane stress or maximum bending stress in primary members under test conditions shall not exceed 0.9 ReH at the test temperature. To ensure that this condition is satisfied, when calculations indicate that this stress exceeds 0.75 ReH, the prototype test shall be monitored by the use of strain gauges or other suitable equipment.

3 Local strength of cargo tanks 3.1 Internal pressure in cargo tanks -8

3.1.1 Cargo tank pressure at 10 probability level is calculated using the acceleration ellipsoid with 8 component accelerations corresponding to 10 wave encounters defined in Sec.1 [3.2] - General North Atlantic. The guidance formulas in Sec.4 [6.1.2] are normally to be applied for type A tanks. For type B tanks direct wave load analysis shall be carried out and the accelerations from direct wave analysis shall be used. However the guidance formulas in Sec.4 [6.1.2] shall be used in the early design stage when the acceleration from direct wave analysis are not available. 3.1.2 Internal pressure including the influence on pressure head from the dome shall be calculated as described in Sec.4 [6.1.1]. 3.1.3 The acceleration aβ is calculated by combining the three component accelerations ax, ay and az values according to an ellipsoid surface, Sec.4 Figure 1. For type B tanks the acceleration shall be based on direct wave load analysis as outlined in DNVGL-CG-0130 Wave load analysis. 3.1.4 The internal pressure in cargo tanks given in this section is based on the assumption of tight CL bulkhead, but with one cargo dome with common vapour pressure on both sides. The filling level is assumed the same at port and starboard side for all seagoing conditions. In case of other arrangement, a case-by-case evaluation will be required.

3.2 Requirements for local scantlings 3.2.1 General The requirement below is applicable for both A-type tanks and B-type tanks. Tank boundary scantlings shall meet at least the requirements of the Society for deep tanks taking into account internal pressure as indicated in Sec.4 [3.3.2] and any corrosion allowance required by Sec.4 [2.1.5]. 3.2.2 Tank shell plating The net thickness requirement in mm for the tank shell plating corresponding to lateral pressure is given by:

where:

Peq b σall

2

2

= pressure as given in [3.1], in kN/m (1 bar = 100 kN/m ) = shortest width of plate in mm, measured along the plating as defined in Pt.3 Ch.3 Sec.7 2

= allowable stress in N/mm as given in [3.2.4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 217

Part 5 Chapter 7 Section 20

.2

tmin = max[0.01b;8.0] Regarding corrosion additions for cargo tanks, see Sec.4 [2.1.5]. 3.2.3 Section modulus for stiffeners The net section modulus requirement for simple stiffeners is given by:

where: = stiffener spacing in mm as defined in Pt.3 Ch.3 Sec.7 s ℓbdg = bending span of stiffener, in m, as defined in Pt.3 Ch.3 Sec.7 fbdg = bending moment factor taken as: — 7.5 for vertical stiffeners simply supported at one or both ends — 10 for transverse stiffeners and vertical stiffeners which may be considered fixed at both ends — 12 for longitudinal stiffeners which may be considered fixed at both ends. The fbdg factor may be adjusted for members with boundary condition not corresponding to the above specification. 3.2.4 Allowable stress, σall For tanks primarily constructed of plane surfaces, the nominal allowable stresses for primary supporting members (web frames, stringers, girders), secondary members (stiffeners) and tertiary members (plating), when calculated by classical analysis procedures, shall for nickel steels, carbon-manganese steels, austenitic steels and aluminium alloys not exceed the lower of: σall = min(Rm/C; ReH/D) where:

Rm ReH

2

= minimum specified tensile strength in N/mm at room temperature 2

= yield stress in N/mm at room temperature, as defined in Sec.1 [3.2].

The stress factors, C and D, are given in Table 1. Table 1 Allowable stress factors for local scantlings, AC-II Stress factors

Primary and secondary (stiffeners)

Tertiary (plating)

C

2.66

-

D

1.33

1.1

Guidance note: Primary members should be checked with FE analysis as described in [4], whereas plates and stiffeners are checked with the prescriptive requirements in [3.2.2] and [3.2.3] with stress factors from Table 1. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 218

Part 5 Chapter 7 Section 20

The minimum net thickness requirement in mm is:

3.2.6 Connection area Connection area of stiffeners shall be according to Pt.3 Ch.6 Sec.7 with design pressure in [3.1.2] based on the combined total acceleration from the acceleration ellipsoid aβ, calculated from the acceleration components ax, ay and

az.

3.2.7 Sloshing loads and scantling requirements Design formulas for sloshing loads on bulkheads, girders, web frames and stringers are given in Pt.3 Ch.10 Sec.4 [2.2] to Pt.3 Ch.10 Sec.4 [2.4], design load scenarios in Pt.3 Ch.10 Sec.4 [2.1.1] and scantling requirements for plates, stiffeners and primary supporting members in Pt.3 Ch.10 Sec.4 [3.1] and Pt.3 Ch.10 Sec.4 [3.2]. The above procedures are the base case requirements for design against inertia and impact sloshing pressures. In case of special geometries and/or novel designs the Society may require more elaborate analyses (CFD) and/or experiments. 3.2.8 Longitudinal bulkhead Longitudinal bulkhead shall be verified based on the condition that one side of tank is filled and another side of tank is empty in harbour condition (one side overfilling). The pressure need not be applied higher than top of longitudinal bulkhead. The acceptance criteria AC-I shall be applied

4 Cargo tank and hull finite element analysis 4.1 General 4.1.1 For gas carriers with independent tanks, constructed mainly of plane surfaces, 3D structural analysis shall be carried out for the evaluation of a cargo tank, tank supports and hull structures. An integrated cargo hold and cargo tank finite element model shall be established to determine reaction forces in supports and to assess the structural adequacy of primary members of the cargo tank, tanks supports and associated hull structure under hull girder bending, external and internal loads. 4.1.2 Model extent For A type tanks the midship region shall be modelled as a minimum, but additional analyses for the fore and/or aft cargo hold regions may be required by the Society depending on the actual tank/ship design configuration if fore and aft region deviates significantly from the midship region. For B type tanks, in addition to the midship region fore and aft cargo hold regions are mandatory for FE analysis to be carried out. The necessary longitudinal extent of the model will depend on the structural arrangement and the loading conditions. The analysis model shall normally extended over three hold lengths (1+1+1), where the middle tank/hold of the model is used to assess the yield and buckling strength. However, shorter models may be accepted by the Society when relevant. The model shall cover the full breadth of the ship in order to account for asymmetric structural layout of the cargo tank/supporting hull structure and asymmetric design load conditions (heeled or unsymmetrical loading conditions).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 219

Part 5 Chapter 7 Section 20

3.2.5 Stiffeners with large deflections Stiffeners subjected to high relative deflections, e.g. horizontal stiffeners between transverse bulkhead and neighboring web frame shall be verified with consideration of relative deflection. The relative deflection can be calculated by FE cargo hold analysis and the stress induced by relative deflection can be assessed according to DNVGL-CG-0129 Sec.4 [7.5]. The total stress combining local bending and relative deflection shall not exceed a permissible stress applying stress factor D = 1.47 for static loads (AC-I) and D = 1.1 for static plus dynamic loads (AC-II).

4.2.1 General The design load cases shall be selected based on actual loading conditions from vessel’s loading manual. 4.2.2 Selection of loading conditions The design loading conditions shall include fully loaded condition, alternate conditions, with realistic combinations of full and empty cargo tanks, with sea pressure/tank pressure, giving maximum net loads on cargo tanks, tank supports and double bottom structures. The ship should be able to operate with any tank empty and the others full, if applicable. The cargo tank and hull stress response shall be maximized when combining internal and external loads with hull girder bending. The worst combination of loads shall be considered. 4.2.3 Accidental loads The tanks and the tank supports shall be designed for the accidental loads and design conditions specified in Sec.4 [2.1.4].3 and Sec.4 [3.5], as relevant. 4.2.4 Load cases Design load cases shall be selected to cover all relevant loading conditions for independent tanks constructed mainly of plane surfaces. Static (S) and dynamic (D) design loads; bending moments, torsional moments (as applicable), maximum cargo accelerations and sea pressure shall be applied to the cargo hold finite element model and serve as basis for design against yield and buckling of the cargo tank, the supports and the hull structure. 4.2.5 Ship hull The dynamic Equivalent design waves (EDWs) for ultimate strength assessment (ULS) defined in Pt.3 Ch.4 Sec.2 shall be applied. 4.2.6 Cargo containment For A-type tank and support design the following EDWs defined in Pt.3 Ch.4 Sec.2 shall be specifically .1 considered for ULS analysis: — for maximum vertical acceleration, BSP-1 and BSP-2 port (P) and/or starboard (S) — for maximum transverse acceleration, BSR-1 and BSR-2, port (P) and/or starboard (S). The port (P) and/or starboard (S) versions shall be selected based on the geometry/symmetry of the construction.

.2

For B-tanks dynamic ultimate design waves (UDWs) defined in Sec.1, shall be determined from linear hydrodynamic analyses, all headings included, maximizing: — vertical acceleration and — transverse acceleration. The procedure for determining the UDWs given in DNVGL-CG-0130 Wave load analysis, shall be used.

.3

In addition, the following design conditions shall be examined for both type A-tanks and type B-tanks: — static condition with 30 degree heel, (ULS) — cargo tank CL bulkhead to be checked for one sided static pressure, (ULS) — flooded condition with one tank empty at full draught with 54% of North Atlantic wave bending moment, (ALS) — crash stop collision load of 0.5 g forward and 0.25 g aftwards combined with still water loads, but no dynamic hull girder loads, (ALS) — damaged condition with flooding in hold with empty cargo tank for checking of anti-floatation support and hull structure in way of anti-floatation support, (ALS)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 220

Part 5 Chapter 7 Section 20

4.2 Loading conditions and design load cases

4.2.7 Pressure loads 2 Sea pressure and internal pressure, Pex and Pin in kN/m , shall be as given in Pt.3 Ch.4 Sec.5 and Pt.3 Ch.4 Sec.6 respectively. For type B-tanks the accelerations shall be determined by direct hydrodynamic analysis. The weight of cargo tank and hull structures shall be included in the FE analysis.

4.3 Acceptance criteria for cargo hold finite element analysis 4.3.1 Application The ship hull including the double hull construction with inner hull plating and stiffeners shall be subject to ship hull design criteria with usage factors given in Pt.3 Ch.7 Sec.3 [4] for yield and Pt.3 Ch.8 Sec.1 [3] for buckling. The cargo tanks with supports shall be subject to tank design acceptance criteria for allowable stress [4.3.4] and buckling [4.3.5]. 4.3.2 Equivalent stress and summation of static and dynamic stresses 2 The equivalent von Mises stress in N/mm shall be calculated according to the formula:

where:

σx σy τxy

= total normal stress in x-direction, in N/mm = total normal stress in y-direction, in N/mm

2 2 2

= total shear stress in the x-y plane, in N/mm .

4.3.3 Determination of dynamic stresses and stress summation The equivalent design waves (EDWs) defined in [4.2.6].1 for A-tanks and the UDWs described in [4.2.6].2 for B-tanks shall be used for determining the dynamic parts of the stress components σx, σy and τxy in any point of the cargo tanks and the supports. Since all dynamic stresses in a design wave approach are acting simultaneously, i.e. in phase – same time instant, linear summation of static and dynamic components can be made. In special cases, e.g. when envelope values are used, the methods given in the guidance below may be used.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 221

Part 5 Chapter 7 Section 20

— damaged condition with flooding in hold with full cargo tank for checking of transverse bulkhead strength, (ALS).

2

Total stresses, in N/mm , in given directions in any point of a structure may be calculated according to the following formulae:

σxs, σys and τxys are static stresses in N/mm2. σxdn, σydn and τxydn are dynamic component stresses in N/mm2, determined separately from acceleration components and hull strain components due to deflection and torsion. Coupling effects should be considered if the dynamic component stresses in a given direction may not be assumed to act independently. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.3.4 Allowable stress For cargo tank and support structures subject to static and dynamic loads, the allowable membrane equivalent stress for AC-II is:

where:

C and D are given in Table 2. The allowable usage factor for AC-II is:

Table 2 Allowable stress factors for FE analysis: ULS and ALS design Design condition (limit state)

ULS (AC-II) type A ALS (AC-III)

ULS (AC-II) type B ALS (AC-III))

Stress factors

Nickel steels and carbonmanganese steels

Austenitic steels

C

1.7

D

1.1

C

1.5

D

1.0

Aluminium alloys

C

2

2.5

2.5

D

1.2

1.2

1.2

C

1.5

1.5

1.5

D

1.0

1.0

1.0

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 222

Part 5 Chapter 7 Section 20

Guidance note:

Allowable stresses in sub-regions and design details will be considered by the Society on a case by case basis. Thermal stresses shall be considered as given in [1.2.6]. 4.3.5 Buckling acceptance criteria Allowable usage factors for primary members subjected to ULS and ALS design conditions are given in Table 3 below. Table 3 Allowable buckling usage factors for cargo tank analysis Design condition (limit state)

Cargo tanks and tank supports

Hull structures

ULS (AC-II)

0.9

1.0

ALS (AC-III))

1.0

1.0

Acceptable usage factors for static load cases (S), AC-I, shall not exceed 70% of the allowable stresses for the (S+D), AC-II, load cases. Guidance note: Due to the severe consequences of potential damages to the cargo tanks the allowable buckling usage factors in Table 3 have in general been reduced with a factor of 0.9 as compared to general ship standard, see Pt.3 Ch.8 Sec.1 [3.3]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5 Local structural strength analysis 5.1 General 5.1.1 Local structural analyses shall be carried out to analyse strength in high stress areas of hull structures and cargo tank/tank supports. Stiffeners subjected to large relative deflections between girders or frames and bulkhead shall be investigated. Local fine mesh analyses may be omitted if the Society considers low cycle fatigue (LCF) or high cycle fatigue (HCF) to be more relevant for the actual location.

5.2 Locations to be checked 5.2.1 The following areas in the midship cargo region shown in the list below shall be investigated with fine mesh analysis. The scope of fine mesh analysis for these areas may be determined based on a screening of the actual geometry and the results from the cargo hold analysis. If considered necessary, the Society may require additional locations to be analysed:

1

hull structures — double hull longitudinals subject to large relative deformation — upper and lower ends of vertical frames at single side shell — vertical stiffeners on transverse watertight bulkheads to inner bottom.

2

cargo tanks and tank supports including associated hull structures — vertical supports (including bottom stiffeners at end of tank, if relevant) — upper and lower transverse support

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 223

Part 5 Chapter 7 Section 20

Nominal stresses for static load cases (S), AC-I, shall not exceed 70% of the allowable stresses for the (S +D), AC-II, load cases.

5.3 Fine mesh FE models 5.3.1 The principles of sub-modelling and application of loads on sub-models shall follow the procedures in DNVGL-CG-0127 Finite element analysis. The procedure is based on the application of 50 mm × 50 mm quadrilateral elements.

5.4 Acceptance criteria 5.4.1 The acceptance criteria given in this sub section apply unless more detail analysis of high cycle and low cycle fatigue strength are carried out. The von Mises equivalent stress shall be calculated based on the membrane axial and shear stresses of the plate element evaluated at the element centroid. Where shell elements are used, the stresses shall be evaluated at the mid plane of the element (membrane stress). 5.4.2 It is required that the resulting von Mises stresses are not exceeding the allowable membrane values specified in Table 4. These criteria apply to regions where stress concentrations occur due to irregular geometries. Nominal stresses shall remain within the limits for cargo hold analysis. 5.4.3 When mesh sizes smaller than 50 mm × 50 mm is used, the average stress shall be calculated based on stresses at the element centroid. Stress averaging is not to be carried across structural discontinuities and abutting structure. Table 4 Maximum allowable membrane stresses for local fine mesh analysis Element stress

Allowable stresses

Acceptance criteria

AC-I

AC-II

AC-III

Load components

ULS (S)

USL (S+D)

ALS (A)

element not adjacent to weld (base material)

1.07 ReHκ

1.53 ReHκ

2.04ReH

element adjacent to weld

0.95 ReHκ

1.35 ReHκ

1.8ReH

cargo tanks and tank supports

ship hull structure including double hull with inner hull plating and stiffeners 1)

The material factor

according to Pt.3 Ch.7 Sec.4 [4.2]

κ for cargo tanks and supports is given in [4.3.4]. ReHκ accounts for the specified minimum

material tensile strength. 2)

The maximum allowable stresses are based on the mesh size of 50 mm × 50 mm. Where a smaller mesh size is used, an average von Mises stress calculated over an area equal to the specified mesh size may be used to compare with the permissible stresses.

3)

Average von Mises stress shall be calculated according to Pt.3 Ch.7 Sec.4 [4.2.1].

5.5 Acceptance criteria for wood, resin and dam plates 5.5.1 A minimum safety factor as followsshall be applied for wood and resin: — 3 for acceptance criteria AC-II

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 224

Part 5 Chapter 7 Section 20

— upper and lower longitudinal support — anti-floatation supports.

The allowable shear stress for the strength of dam plates is

.

5.5.2 Material strength data shall be supplied by the designer based on certification of the relevant materials.

6 Thermal analysis 6.1 General 6.1.1 To determine the grade of plate and sections used in the hull structure, a temperature calculation shall be performed for both type A and type B tanks when the cargo temperature is below -10°C, Sec.4 [5.1.1] .1. 6.1.2 If not available from similar designs, steady state thermal analysis of the cargo hold area and the cargo tank shall be performed to: — determine steel temperature as basis for material quality selection of the surrounding hull structure and as input to thermal stress analysis, and — to confirm the structural integrity of the cargo tank, tanks supports and supporting hull structure with respect to yield and buckling in partial and full load conditions. For type A-tanks reference is made to [1.1.4] and [1.2.6]. 6.1.3 Transient thermally induced loads during cooling down periods shall be considered for tanks intended for cargo temperatures below -55°C. 6.1.4 Thermal expansion coefficient of the material of the cargo tank shall be supplied by/documented by the designer. 6.1.5 Simplified 2-D models and/or 3-D FE models may be used as applicable. Guidance note: If a 3-D model is deemed necessary, the integrated cargo hold/tank finite element model specified in [4.1] can be used for the thermal stress analysis. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.2 Thermal stress analysis 6.2.1 Load cases should at least be considered as follows: — full load condition, i.e. 98% filling, to determine maximum cool-down of surrounding hull structure — partial load condition, filling to each stringer level as relevant to determine stress ranges for low cycle fatigue analysis for the full thermal cycle due to loading and unloading of cargo. 6.2.2 Thermal loads due to the calculated/measured temperature distributions shall be applied over the tank height for each design load case. 6.2.3 For partial load conditions and full load condition, thermal loads, static cargo pressure and minimum design vapour pressure shall be applied. Deflection of double bottom structure shall be taken into account for all load conditions. If a tank is divided by longitudinal or/and transverse liquid tight bulkheads in a common tank space, the possible loading patterns of the tank shall be considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 225

Part 5 Chapter 7 Section 20

— 2 for acceptance criteria AC-III.

6.3.1 The acceptance criteria for the ULS design condition given in [4] and [5] applies for thermal induced stress analysis.

7 Sloshing assessment 7.1 General 7.1.1 For partial tank fillings the risk of significant loads due to sloshing induced by ship motions shall be considered. 7.1.2 Interaction of liquid sloshing motion with the natural ship motion periods should be avoided. Normally, the lowest natural liquid periods should be 20% away from the natural ship motion periods. The fitting of swash bulkheads can move the liquid resonance periods away from the motion periods of the ship and significantly reduce the risk of sloshing loads inside the tanks. Guidance note: Natural periods for liquid motion in prismatic tanks can be estimated as described in Pt.3 Ch.10 Sec.4 [2.4.2]. For a general description of sloshing phenomena, see DNVGL-CG-0158 Sloshing analysis of LNG membrane tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.3 For tanks built without swash bulkheads and/or longitudinal bulkhead the need for documentation by more advanced sloshing analyses, e.g. CFD, and/or model testing will be determined by the Society.

7.2 Sloshing strength analysis 7.2.1 The tank boundary structure including swash bulkheads should be designed to withstand loads caused by liquid sloshing. The design sloshing pressures shall be explicitly considered in the scantling requirements of plates and stiffeners. 7.2.2 As a minimum the tank shall be designed for the sloshing inertia and liquid impact pressure loads given in Pt.3 Ch.10 Sec.4. Based on experience, this will normally be considered sufficient if swash bulkheads are arranged to reduce liquid sloshing resonances in the tanks. 7.2.3 The acceptance criteria for strength analysis shall follow the AC-I and AC-IV criteria for internal sloshing loads and liquid impact loads respectively, see Pt.3 Ch.10 Sec.4, with ReHκ representing the specified minimum material strength, i.e. yield equivalent. Where

κ is according to [4.3.4].

8 Fatigue analysis 8.1 General 8.1.1 Hull structure Fatigue strength of hull structures for both type A and type B tanks shall be determined according to Pt.3 Ch.9. Additional requirements may apply for the hull structure depending on class notations, e.g. Plus, CSA.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 226

Part 5 Chapter 7 Section 20

6.3 Acceptance criteria

8.1.3 B-tanks For independent tank type B, fatigue life and crack propagation analyses are required for the design of the tank with small leak protection system. The fatigue design shall be based on direct hydrodynamic wave load 8 analysis with a minimum of 10 load cycles in North Atlantic environment. 8.1.4 Construction tolerances Fatigue analysis shall consider construction tolerances.

8.2 Locations to be considered 8.2.1 The fatigue strength assessment shall be carried out for cargo tank, tank supports and hull structures in the cargo area as specified below. Additional areas may have to be analysed based on specific structural configurations:

.1

hull structures — hopper knuckles — liquid dome opening and liquid dome coaming connection to deck, type B tanks — side stringer connections to transverse bulkheads, type B tanks.

.2

cargo tank, see also [1.2.6] and [8.1.2] — — — — —

stiffener end connections tank structure in general tanks in way of supports tank supports. cargo pump/riser support.

8.3 Loading conditions 8.3.1 Fatigue analyses shall be carried out for representative loading conditions according to the ship’s intended operation as given in the loading manual (the trim and stability booklet). The following loading conditions shall be represented as applicable: 8.3.2 Hull structure — Homogeneous full load condition at design draught (departure). — Ballast condition at normal ballast draught (arrival). If a normal ballast condition is not defined in the loading manual, minimum ballast draught shall be used. 8.3.3 Tank and tank supports — Homogeneous full load condition at design draught (departure). — Partial tank fillings as relevant. Sloshing effects shall be considered. — Ballast condition at normal ballast draught (arrival). If a normal ballast condition is not defined in the loading manual, minimum ballast draught should be used (10% filling in the cargo tank if applicable). 8.3.4 Cargo pump/riser supports or cargo pipe attachment to cargo tank — Partial fillings: If relevant a minimum of 3 part filling levels shall be used.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 227

Part 5 Chapter 7 Section 20

8.1.2 A-tanks Fatigue analysis for proven designs of independent tank type A may normally not be considered for the cargo tanks. With design cargo temperature below –55°C, fatigue analysis shall be carried out. The analysis shall 8 be referred to a minimum of 10 load cycles in North Atlantic environment for tanks and tank supports with damage factor Cw ≤ 1.0.

8.4 Load cases 8.4.1 Hull structures The dynamic equivalent design waves (EDWs) for fatigue assessment (FLS) defined in Pt.3 Ch.4 Sec.2 [3] shall be applied. 8.4.2 Cargo tanks and supports o For novel type A tank designs, and/or when the cargo temperature is below –55 C all EDWs defined in .1 Pt.3 Ch.4 Sec.2 [3] shall be considered for FLS analysis of tanks and tank supports.

.2

For B-tanks dynamic fatigue design waves (FDWs) shall be determined from linear hydrodynamic analyses, all headings included, maximizing: — vertical acceleration — transverse acceleration, and — longitudinal acceleration.

.3

The dynamic stress range shall be determined as the difference between the results from the 1 and the 2, i.e. HSM-1 and HSM-2, versions of the rule EDWs and the directly calculated FLS design waves (FDWs) for A and B type tanks respectively. Guidance note: For determining FDWs for B-tanks reference is made to DNVGL-CG-0130 Wave load analysis. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

8.5 Acceptance criteria 8.5.1 The fatigue damage ratio may be calculated based on the S-N fatigue approach under the assumption of linear cumulative damage, i.e. the Miner-Palmgren method. Acceptable fatigue damage ratios are specified in Table 5. The table refers to the principle of leak-before-failure (LBF) as defined in Sec.4 [2.2.6]. Table 5 Required fatigue damage ratios, CW Area type B-tanks: primary barrier of cargo tank, i.e. outer tank shell plates, attached stiffeners and adjacent structure

Requirement

Environment

Comment

for failures that can be reliably detected by means of leakage detection: — Cw ≤ 0.5 — predicted remaining failure development time, from the point of detection of leakage till reaching a critical state, shall not be less than 15 days unless different requirements apply for ships engaged in particular voyages

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

North Atlantic

leak-beforefailure (LBF) proven

Page 228

Part 5 Chapter 7 Section 20

— Ballast condition at normal ballast draught (arrival). If a normal ballast condition is not defined in the loading manual, minimum ballast draught should be used.

type B-tanks: primary supporting structures, i.e. girders, stringers, web frames in cargo tanks

type B-tanks: primary barrier, secondary and tertiary structures where relevant

type B-tanks: tank supports and associated hull structure

Requirement

Environment

Comment

for failures that cannot be detected by leakage detection system but can be reliably be detected at the time of inservice inspections — Cw ≤ 0.5 — predicted remaining failure development time, from the largest crack not detectable by in- service inspection methods until reaching a critical state, shall not be less than three (3) times the inspection interval. in particular locations of the tank where effective defect or crack development detection cannot be assured, the following, more stringent, fatigue acceptance criteria should be applied as a minimum: — Cw ≤ 0.1

North Atlantic

No leakage detection, not LBF

North Atlantic

no leakage detection, not LBF

— predicted failure development time from the assumed initial defect until reaching a critical state, shall not be less than three (3) times the lifetime of the tank. North Atlantic

— Cw ≤ 0.5

type A-tanks: primary barrier, secondary, tertiary structures, tank supports and supporting hull structure

— Cw ≤ 1.0

North Atlantic

for novel designs and/ or for cargo temperature below -55°C

hull structure in general

— Cw ≤ 1.0

world wide

follow procedures in Pt.3 Ch.9

9 Crack propagation analysis 9.1 General 9.1.1 For type B tanks fracture mechanics analyses shall be carried out for dynamically loaded weld connections in the tank shell structure and internal girder/frame structure. For details located in the tank shell structure including shell stiffeners and parts of webs/girders adjacent to the shell, the analyses shall be used to determine if:

.1

a crack penetrates through the plate thickness of the primary barrier and remains stable for at least 15 days from time of detection of leaks in the worst storm conditions, or

.2

the crack does not go through the thickness, but grows in length due to dominating bending stress over the plate thickness.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 229

Part 5 Chapter 7 Section 20

Area

9.2.1 The size of initial defects to be used in the analysis shall be decided considering the production quality of the builder. Normally, if the Society does not decide otherwise, the following initial defect sizes can be used for failures originating in the primary barrier plate in way of the heat affected zone (HAZ) from welding: — butt welds : 1.0 mm depth and 5 mm in length — fillet welds : 0.5 mm depth and 5 mm in length For failures originating elsewhere, e.g. from end connections of primary barrier stiffeners, the initial crack size in the shell plating shall be determined considering the development of the crack through the stiffener.

9.3 Acceptance criteria 9.3.1 The acceptance criteria described in [8.5.1] shall be satisfied.

9.4 Leak rates 9.4.1 Leak rates through cracks in the outer shell plates (the primary barrier) shall be determined. The requirements to the drip tray and gas venting arrangement to dispose of leakages are given in Sec.4 [2.5]. Guidance note: For details on crack propagation analysis procedures and the determination of leak rates reference is made to DNVGL-CG-0133, Liquefied gas carriers with independent prismatic tanks of type A and B. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

10 Vibration analysis 10.1 Requirements 10.1.1 For type B tanks a vibration analysis shall be carried out for the various structural components of the tank in order to obtain the natural frequencies for the significant modes of vibration. Due attention shall be given to the effect of liquid, rotational restraint, flange stiffness and cut-outs on the natural frequencies. Guidance note: The natural frequencies for the significant modes of vibration of a structural component should comply with the following requirements: Motor-driven ships: f · Δ ≥ 1.1 F Turbine-driven ships: f · Δ ≥ 1.1 F or f · Δ ≤ 0.55 F

f

=

natural frequency for the actual mode of vibration in air (Hz.)

Δ =

reduction factor for the natural frequency when the structural component is immersed in liquid

F =

highest local excitation frequency expected to be of significance plus 10% (Hz.) ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 230

Part 5 Chapter 7 Section 20

9.2 Initial defects to be used

1 General 1.1 Design basis 1.1.1 Hull design The hull design shall be carried out according to main class requirements in Pt.3 of the rules. In addition, the present rules for liquefied gas carriers, this section give additional design requirements for liquefied gas carriers with independent spherical type B tanks. 1.1.2 Cargo tank design Spherical tanks are type B independent tanks and shall be designed using model tests, refined .1 analytical tools and analysis methods to determine stress levels, fatigue life and crack propagation characteristics.

.2

If the cargo temperature at atmospheric pressure is below -10°C, a partial secondary barrier with a small leak protection system shall be provided as required in Sec.4 [2.3]. The small leak protection system shall be designed according to Sec.4 [2.5].

.3

The design vapour pressure shall be less than 0.07 MPa, but shall not be taken to be less than 0.025 MPa.

1.2 Spherical cargo tank system 1.2.1 Cargo tank Spherical cargo tanks are normally built in aluminium, Al 5083-0. However, low temperature steel may also be used, e.g. 9% Ni steel. See Sec.6 for material specifications. Figure 1 shows the arrangement of a conventional spherical tank design. The spherical tank is supported at the equator of the sphere by a cylindrical skirt welded to the foundation deck. 1.2.2 Equator profile The equator profile is designed to give optimal fatigue life taking the stress and relative movement between tank and hull into consideration. 1.2.3 Cylindrical skirt The skirt supports the tank and is designed to act as a thermal brake between the tank and the hull structure by reducing the thermal conduction from the tank to the supporting structure. It is built up of three parts, the upper part in which the same material as in the sphere is used, the middle stainless steel part (the thermal brake) and the lower carbon steel part, see Figure 1. 1.2.4 Structural transition joint (STJ) The STJ joint connects the upper aluminium part and the middle stainless steel part of the skirt for cargo tanks made of aluminium. 1.2.5 Tank insulation The insulation forms an annular space between the tank and the insulation barrier. The space shall be continuously purged with Nitrogen and supplied with a gas detection system. The nitrogen purging also prevents icing between the tank and the insulation. Any possible leakage shall be led via the annular gap down to the drip pan.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 231

Part 5 Chapter 7 Section 21

SECTION 21 DESIGN WITH SPHERICAL INDEPENDENT TANKS OF TYPE-B

Insulation is typically provided according to one of the two following principles: —

extruded polystyrene-foam logs are butt-welded and fed as a long string from platform outside of hold space, also referred to as spiral generation

—

studs welded to tank surface support expanded polystyrene panels applied prior or after erection of tank into the hull. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Figure 1 Spherical tank system and cargo hold configuration 1.2.6 Drip tray The drip tray is placed below the cargo tank and act as the partial secondary barrier, i.e. the small leak protection system. The drip tray shall be designed to hold the maximum calculated leak during 15 days after leakage detection in the most severe weather conditions in the North Atlantic. The drip tray shall be insulated towards the inner bottom and designed to prevent splashing of the leaked cargo onto the inner bottom, usually achieved by fitting of internal ribs. Evaporation of the leaked cargo is normally achieved by blowing the drip tray with nitrogen.

1.3 Structural analysis of cargo tanks 1.3.1 Design conditions The effects of all dynamic and static loads shall be used to determine the suitability of the structure with respect to the following limit state conditions: — ultimate limit state design condition (ULS)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 232

Part 5 Chapter 7 Section 21

Guidance note:

— fatigue limit state design condition (FLS) — fatigue failure, and — crack propagation analysis. — accident limit state design condition (ALS) — plastic deformation — buckling. Finite element analysis and/or prescriptive requirements and fracture mechanics analysis shall be applied. 1.3.2 Structural analyses A three-dimensional analysis shall be carried out to evaluate stress levels, including interaction with the ship's hull. The model for this analysis shall include the cargo tank with its supporting structure, as well as a reasonable part of the hull. 1.3.3 Wave load analysis A direct hydrodynamic analysis of the particular ship accelerations and motions in irregular waves, and of the structural response of the ship and its cargo tanks to these forces and motions shall be performed, unless the data is available from similar ships. 1.3.4 Fracture mechanics analyses Crack propagation analyses and design against brittle fracture shall be carried out according to recognized standards, e.g. BS7910. A fracture mechanics analysis according to Sec.4 [4.3.3] .6 to Sec.4 [4.3.3] .9 is required. 1.3.5 Model testing Model tests may be required to determine material properties for yield and fracture mechanics analyses, stress concentration factors and fatigue life of structural elements, Sec.4 [4.3.3] .6 and .7.

2 Cargo tank and hull finite element analysis 2.1 General 2.1.1 For gas carriers with spherical independent tanks, 3D structural analysis shall be carried out for the evaluation of cargo tanks, tank supports and hull structures. 2.1.2 Model extent For the evaluation of cargo tanks and supporting structures in way of cargo tank, full integrated 3D model of the whole ship hull with cargo tanks and tank covers shall normally be used. However, part ship models may be accepted by the Society. For the evaluation of cargo hold hull structures, three (3) cargo hold length model is normally to be used. 2.1.3 Static and dynamic interaction forces shall be determined from the global FE model for all relevant loads, i.e. hull girder bending, torsion and external and internal loads. Depending on the particular ship design the size and fineness of the FE models will be determined by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 233

Part 5 Chapter 7 Section 21

— plastic deformation — buckling.

2.2.1 The loading conditions shall be reflected in the loading manual and include the following conditions: a) b) c) d)

homogeneous loading conditions for all approved cargoes ballast conditions one or more tanks empty or partially filled harbour condition for which an increased vapour pressure has been approved. Guidance note: Conditions a), b) and c) above refers to relevant design conditions for the hull and tank structure. Condition d) refers to emergency discharge of the tanks in case of failure of the cargo pumps and is a structural condition for the tanks only. If two cargo pumps are fitted inside each cargo tank emergency discharge need not be considered/designed for, see Sec.5 [6.1.1] and Sec.5 [6.1.2]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

The design load cases shall be selected based on actual loading conditions from vessel’s loading manual. 2.2.2 Selection of loading conditions The design loading conditions shall include fully loaded condition, alternate conditions, with realistic combinations of full and empty cargo tanks, with sea pressure/tank pressure, giving maximum net loads on cargo tanks, tank supports and double bottom structures. The ship should be able to operate with any tank empty and the others full, if applicable. The cargo tank and hull stress response shall be maximized when combining internal and external loads with hull girder bending. The worst combination of loads shall be considered. 2.2.3 Accidental loads The tanks and the tank supports shall be designed for the accidental loads and design conditions specified in Sec.4 [2.1.4] .3 and Sec.4 [3.5], as relevant. 2.2.4 Load cases Design load cases shall be selected to cover all relevant loading conditions for independent spherical tanks. Static (S) and dynamic (D) design loads; bending moments, torsional moments (as applicable), maximum cargo accelerations and sea pressure shall be applied to the finite element model and serve as basis for design of the cargo tanks and the hull structure.

3 Acceptance criteria – hull and cargo tanks 3.1 Ultimate limit state design condition - hull 3.1.1 Yielding Acceptance criteria are given in Pt.3 Ch.6 Sec.4 to Pt.3 Ch.6 Sec.6 for yield control of the hull structures. The criteria cover prescriptive requirements for primary support members, secondary members (stiffeners) and plate panels. Further, acceptance levels for FE cargo hold analyses and fine mesh analyses are given in Pt.3 Ch.7 Sec.3 and Pt.3 Ch.7 Sec.4. 3.1.2 Buckling Acceptance criteria is given in Pt.3 Ch.8 Sec.1 for buckling control of the hull structures. The Buckling check procedures in DNVGL-CG-0128 Buckling, shall be applied. In case of highly irregular geometries and/or boundary conditions, nonlinear FE analyses may have to be carried out in order to determine the buckling strength of specific areas. In such cases, i.e. by using non-linear structural analysis programs, special considerations with respect to modelling, e.g. mesh fineness, imperfection levels/modes and acceptance levels is required and will be considered by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 234

Part 5 Chapter 7 Section 21

2.2 Loading conditions and design load cases

Part 5 Chapter 7 Section 21

3.2 Ultimate limit state design condition - cargo tanks 3.2.1 Basic conditions The analyses shall be based on the conditions in Sec.4 [4.3.2]. 3.2.2 Allowable stress for plastic deformation For spherical tanks (sphere and skirt) the allowable stresses shall not exceed:

σm

≤f

σL

≤ 1.5 f

σb

≤ 1.5 F

σL + σb

≤ 1.5 F

σm + σb

≤ 1.5 F

σm + σb + σg

≤ 3.0 F

σL + σb + σg

≤ 3.0 F

where: 2

σm σL σb

= equivalent von Mises primary general membrane stress, in N/mm

σg

= equivalent von Mises secondary stress, in N/mm

2

= equivalent von Mises primary local membrane stress, in N/mm = equivalent von Mises primary bending stress, in N/mm

2

2

where:

ReH Rm

2

= minimum specified yield strength in N/mm as defined in Sec.1 2

= minimum specified tensile strength in N/mm as defined in Sec.1

Stress factors to be used for ULS analyses are given in Table 1. Table 1 Allowable stress factors for ULS design, AC-II Stress factors

Nickel steels and carbonmanganese steels

Austenitic steels

Aluminium alloys

A

3

3.5

4

B

2

1.6

1.5

C

3

3

3

D

1.5

1.5

1.5

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 235

.2

Buckling criteria and acceptance levels for the spherical tanks and the skirts shall be according to DNVGL-CG-0134 App.D. The acceptance criteria are given in a partial safety factor format with the partial safety factors given in the document.

.3

For the cylindrical skirt other recognised buckling formulations can be applied if considered applicable by the Society. In such cases the safety level (the partial safety factors) shall provide a safety level not lower than the safety level inherent in .2.

3.2.4 Stress categories and stress definitions Stress categories for interpretation of stress results are defined in Sec.4 [6.1.3].

3.3 Fatigue limit state design condition - cargo tanks 3.3.1 Fatigue design conditions The fatigue and crack propagation analyses shall be carried based on the conditions in Sec.4 [4.3.3]. 3.3.2 Design damage ratios and fracture criteria Acceptable fatigue damage ratios and crack propagation analysis criteria are summarised in Table 2. The table refers to the principle of leak-before-failure (LBF) defined in Sec.4 [2.2.6]. Table 2 Required fatigue damage ratios, CW and associated crack propagation criteria Area

Requirement

primary barrier

for failures that can be reliably detected by means of leakage detection:

— tank shell welds

— Cw ≤ 0.5

— tower supports and — equator area as applicable.

primary barrier — tank shell welds — equator area and — attachments as applicable

— predicted remaining failure development time, from the point of detection of leakage till reaching a critical state, shall not be less than 15 days unless different requirements apply for ships engaged in particular voyages

Environment

North Atlantic

— predicted remaining failure development time, from the largest crack not detectable by in- service inspection methods until reaching a critical state, shall not be less than three (3) times the inspection interval

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

leak-before-failure (LBF) proven Sec.4 [2.2.6] Sec.4 [4.3.3] .7

for failures that cannot be detected by leakage but can be reliably be detected at the time of in-service inspections: — Cw ≤ 0.5

Comment

North Atlantic

no leakage detection, not LBF Sec.4 [4.3.3] .8

Page 236

Part 5 Chapter 7 Section 21

3.2.3 Buckling criteria for cargo tanks Buckling strength analyses of cargo tanks subject to external pressure and other loads causing .1 compressive stresses shall be carried out in accordance with .2 and .3. The method shall adequately account for the difference in theoretical and actual buckling stress as a result of plate edge misalignment, lack of straightness or flatness, ovality and deviation from true circular form over a specified arc or chord length, as applicable.

primary barrier — areas with dominating bending stress — upper horizontal weld to equator profile tank skirt, STJ, foundation deck area and associated hull structure

Requirement

Environment

in particular locations of the tank where effective defect or crack development detection cannot be assured, the following, more stringent, fatigue acceptance criteria should be applied as a minimum:

Comment

no leakage detection, not LBF North Atlantic

— Cw ≤ 0.1 — predicted failure development time from the assumed initial defect until reaching a critical state, shall not be less than three (3) times the lifetime of the tank

— Cw ≤ 0.5

hull structure in general — Cw ≤ 1.0

Sec.4 [4.3.3] .9

North Atlantic

no leakage detection, not LBF

World Wide

follow procedures in Pt.3 Ch.9 and DNVGL DNVGL-CG-0129 Fatigue assessment of ship structures

3.4 Accident design condition - cargo tanks 3.4.1 ALS design conditions The analyses shall be carried out based on the design conditions in Sec.4 [4.3.4]. 3.4.2 Design premises The tanks and the tank supports shall be designed for the accidental loads and design conditions .1 specified in Sec.4 [2.1.4] .3 and Sec.4 [3.5], as applicable.

.2

When subjected to the accidental loads specified in Sec.4 [3.5], the stress shall comply with the acceptance criteria specified in [3.2.2] and [3.2.3], modified as appropriate, taking into account their lower probability of occurrence.

3.4.3 Allowable stress factors Due to the low probability of occurrence higher utilisation of the material is in general allowed for the .1 ALS condition than for the ULS condition, [3.4.2] .2.

.2

Stress factors for the ALS limit State allowing up to full yield utilisation are shown in Table 3. Based on the severity (consequence) of the actual incident the Society will assess the safety level (stress factors), but will generally not accept lower values than given in Table 3.

Table 3 Allowable stress factors for ALS design Stress factors

Nickel steels and carbonmanganese steels

Austenitic steels

Aluminium alloys

A

1.5

1.5

1.5

B

1.0

1.0

1.0

C

1.5

1.5

1.5

D

1.0

1.0

1.0

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 237

Part 5 Chapter 7 Section 21

Area

3.5 Acceptance levels for vibration response Vibration effects with the potential to damage the containment system shall be considered, Sec.4 [3.3.5]. Vibration levels for the tower and tank structure shall be below 10 mm/s unless it is documented that the risk of fatigue cracking is within acceptable limits with a higher vibration level.

4 Thermal analysis 4.1 Temperature analysis 4.1.1 Stationary analysis If not available from similar designs, stationary thermal analysis of cargo hold area and the cargo tank shall be performed as required in Sec.4 [3.3.4] and Sec.4 [5.1.1] .1 in order to:

.1

determine steel temperature as basis for material quality selection of the hull structure and as input to thermal stress analysis, and

.2

to determine temperature loads/stresses in the tank system for use in the structural integrity analyses of the cargo tanks and support systems with respect to yield and buckling in partial and full load conditions. Guidance note: Cool-down from ambient temperature to cargo temperature leads to shrinking of the diameter of the spherical tank and the top of the cylindrical skirt. This imposes an extra eccentricity for the meridional forces in the tank and skirt with additional bending stresses in the equator area as a result. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.2 Transient analysis Analysis of transient thermally induced loads during cooling down periods shall be carried out according .1 to Sec.4 [3.3.4].

.2

The analysis shall be used to limit the loading rate from warm tank considering spraying rate while avoiding overstressing of critical areas at the tank/the equator profile. Guidance note: Simplified 2-D models and/or 3-D FE models may be used as applicable. If a 3-D model is deemed necessary, an integrated cargo hold/tank finite element model should be used for the temperature - and thermal stress analyses ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.2 Acceptance criteria The acceptance criteria for the ULS design condition for yielding and buckling in [3.2.2] and [3.2.3] applies for the combined set of mechanically and thermally induced stress.

5 Sloshing 5.1 Sloshing loads 5.1.1 Effect to be considered Liquid sloshing effects shall be considered as required in Sec.4 [3.4.4]. .1

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 238

Part 5 Chapter 7 Section 21

3.4.4 Allowable buckling utilisation for ALS The buckling safety factors shall be according to [3.2.3] .2.

Due to the smooth internal surface spherical tanks are not subject to liquid impact loads, but inertia sloshing loads shall be accounted for in the analysis procedure.

6 Testing 6.1 Requirements 6.1.1 Test acceptance criteria and procedures Spherical type B independent tanks shall be subjected to a hydrostatic or hydropneumatic test as follows:

.1

The maximum primary membrane stress or maximum bending stress in primary members under test conditions shall not exceed 0.9 ReH as fabricated at the test temperature.

.2

To ensure that this condition is satisfied, when calculations indicate that this stress exceeds 0.75 ReH, the prototype test shall be monitored by the use of strain gauges or other suitable equipment.

.3

During filling up of the tank, prior to applying internal hydropneumatic overpressure, the lower hemisphere shall be monitored for buckling.

Testing shall be carried out for the skirt as well as the spherical tank itself. Guidance note: In addition to the general requirements in Pt.3 for the hull structure detailed analysis procedures for spherical carrier hull and cargo tank structures are given in DNVGL-CG-0134 Liquefied gas carriers with spherical tanks of type B. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 239

Part 5 Chapter 7 Section 21

.2

1 General 1.1 Design basis 1.1.1 Hull design The hull design shall be carried out according to main class requirements in Pt.3 of the rules. In addition, the present rules for liquefied gas carriers, this section give additional design requirements for liquefied gas carriers with independent cylindrical type C tanks. Design with single side hull structure shall comply with Sec.20 [1.6], as relevant. 1.1.2 The design basis for type C independent tanks is pressure vessel criteria modified to include fracture mechanics and crack propagation criteria. The minimum design vapour pressure defined in [1.2.1] is intended to ensure that dynamic stresses are sufficiently low, so that an initial surface flaw will not propagate more than half the thickness of the shell during the lifetime of the tank. 1.1.3 The class may allocate a tank complying with the criteria of type C minimum design pressure as in [1.2.1], to a type A or type B, dependent on the configuration of the tank and the arrangement of its supports and attachments. 1.1.4 Structural analysis of cargo tanks A structural analysis with integrated model including tanks, hull, tank supports and keying structures shall be performed with direct FE analyses and/or classical methods as relevant. The following limit state design conditions shall be considered for type-C tanks: ultimate limit state design condition (ULS) — plastic deformation — buckling. accident limit state design condition (ALS) — plastic deformation — buckling. Guidance note: Methods for strength analysis of hull structure in liquefied gas carriers with cylindrical Type-C tanks are given in DNVGL-CG-0135 Liquefied gas carriers with independent cylindrical tanks of type C. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.5 In special cases, a fatigue analysis according to Sec.4 [4.3.3] may be required.

1.2 Design loads 1.2.1 Design vapour pressure The vapour pressure, in MPa, used in the design is generally to be taken as given in the specification, and not to be taken less than the maximum allowable relief valve setting (MARVS). However, for the tank to be defined as a tank type C, the minimum vapour pressure as described below shall be satisfied.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 240

Part 5 Chapter 7 Section 22

SECTION 22 DESIGN WITH CYLINDRICAL TANKS OF TYPE-C

with:

σm ΔσA

= design primary membrane stress in N/mm

2 -8

= allowable dynamic membrane stress range, i.e. double amplitude at probability level Q = 10 , taken equal to: 2

— 55 N/mm for ferritic-perlitic, martensitic and austenitic steels 2 — 25 N/mm for aluminium alloy (5083-0).

C

= characteristic tank dimension in m taken equal to: max(h; 0.75b ; 0.45ℓ)

h b ℓ ρr

= height of tank exclusive dome in m, dimension in ship's vertical direction = width of tank in m, dimension in ship's transverse direction = length of tank in m, dimension in ship's longitudinal direction = the relative density of the cargo at the design temperature (ρr = 1 for fresh water)

If other materials than those specified above are used, the allowable dynamic membrane stress ΔσA shall be agreed with the Society. The determination of the maximum dynamic membrane stress ranges for other materials should be based on a crack propagation analysis, assuming a defined initial surface flaw, to ensure a suitable low probability for a crack to propagate through thickness of the shell. 1.2.2 If the carriage of products not covered by Sec.19 is intended, the relative density of which exceeds 1.0, e.g. CO2, it shall be verified that the double amplitude of the primary membrane stress Δσm created by the maximum dynamic pressure differential ΔP does not exceed the allowable double amplitude of the dynamic membrane stress ΔσA as specified in [1.2.1] i.e.: ∆σm ≤ ∆σA The dynamic pressure differential ΔP, in MPa, shall be calculated as follows:

where:

ρ aβ, Zβ aβ1 and Zβ1 aβ2 and Zβ2

3

is maximum liquid cargo density in kg/m at the design temperature are as defined in Sec.4 [6.1.1].2, see also Figure 1 below

aβ and Zβ values giving the maximum liquid pressure (Pgd)max are the aβ and Zβ values giving the minimum liquid pressure (Pgd)min. are the

In order to evaluate the maximum pressure differential ΔP, pressure differentials shall be evaluated over the full range of the acceleration ellipse as shown in the sketches below.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 241

Part 5 Chapter 7 Section 22

where:

1

2

2

2

1

1

2

1

2

Figure 1 Acceleration ellipse used to evaluate pressure differential 1.2.3 Cargo tank pressure The design liquid pressure defined in Sec.4 [3.3.2] shall be taken into account in the internal pressure calculations. The internal pressure, in MPa, used to determine the thickness of any specific part of the tank is given by: P

eq

=P

0

+ (P

gd

)

max

where: P

eq

is determined as detailed in Sec.4 [6.1.1].

For vacuum insulated tanks the vacuum shall be included in the above formula. 1.2.4 External pressure External overpressure shall be applied to the tank shell for empty and partially filled tank conditions to ensure that the buckling capacity of the tank is sufficient to withstand the maximum pressure difference between the minimum internal pressure (maximum vacuum) and the maximum external pressure to which any portion of the tank may be subjected simultaneously. The design external pressure, in MPa, used for verifying the buckling of the pressure vessels, shall not be less than that given by: P

ed

=P

1

+P

2

+P

3

+P

4

where:

P 1 = setting value of vacuum relief valves, in MPa. For vessels not fitted with vacuum relief valves P1 shall be specially considered, but shall not, in general, be taken as less than 0.025 MPa

P 2 = the set pressure of the pressure relief valves (PRVs), in MPa, for completely closed spaces containing pressure vessels or parts of pressure vessel; elsewhere P2= 0

P 3 = compressive loads, in MPa, in or on the shell due to the weight and contraction of thermal insulation,

weight of shell including corrosion allowance and other miscellaneous external pressure loads to which the pressure vessel may be subjected. These include, but are not limited to, weight of domes, weight of towers and piping, effect of product in the partially filled condition, accelerations and hull deflection. In addition, the local effect of external or internal pressures or both shall be taken into account. Unless otherwise documented, as a guidance an external pressure of 0.005 MPa can be applied.

P 4 = external pressure, in MPa, due to head of water for pressure vessels or part of pressure vessels on

exposed decks; elsewhere P4 = 0. P4 may be calculated using the formulae given in Pt.3 Ch.4 Sec.5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 242

Part 5 Chapter 7 Section 22

1

Guidance note: Methods for investigating the sensitivity for sloshing loads are given in the Society's document DNVGL-CG-0135 Sec.1 [4.4]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.6 Thermal loads Separate thermal analysis may be required if it is assumed that large temperature gradients are present in the tank, or if constraints in the tank impose large stresses in the tank structure due to contraction of the tank. Thermal stresses are normally classified as secondary stresses. For selection of hull material grades stationary temperature analysis need to be carried out for the part of the hull supporting the cargo tank and the adjacent structure. These temperature calculations shall be according to Sec.4 [5.1.1]. 1.2.7 Hull interaction loads Horizontal tanks supported by saddles should preferably be supported by two saddle supports only. In this case, the effect of hull interaction is normally small. For tanks supported in such a way that the deflection of the hull transfers significant stresses in the tank, the static and wave induced interaction loads shall be included. The interaction loads may in general be found from a cargo hold analysis, where both the local deflections of the double bottom and the deflections due to hull girder bending are assessed. The wave-induced loads shall be calculated as given in Sec.4 [3.4.2]. For saddle-supported tanks, the supports are also to be calculated for the most severe resulting acceleration. The most probable resulting acceleration in a given direction β may be found as shown in Figure 1. The half axes in the acceleration ellipse may be found from the formulae given in Sec.4 [6.1.2]. In cases where hull interaction loads are significant, separate fatigue evaluations shall be carried out. 1.2.8 Tank test load Tank test shall be done at a pressure of not less than 1.5P0. For vacuum insulated tanks the vacuum pressure shall be included, i.e. 1.5 (P0 + Pvacuum). 1.2.9 Accidental loads The accidental loads and design conditions specified in Sec.4 [2.1.4].3 and Sec.4 [3.5] shall be considered, as applicable.

2 Ultimate strength assessment of cargo tanks 2.1 General requirement 2.1.1 For design against excessive plastic deformation, cylindrical and spherical shells, dished ends and openings and their reinforcement shall be calculated according to [2.3] and [2.7] when subjected to internal pressure only and according to membrane strength check in [2.4] when subjected to external pressure. 2.1.2 An analysis of the stresses imposed on the shell from supports is always to be carried out, see [2.5]. Analysis of stresses from other local loads, thermal stresses and stresses in parts not covered by [2.3] may be required to be submitted. For the purpose of these calculations the stress limits given in [2.8.1] apply. 2.1.3 The buckling criteria to be applied shall allow for the actual shape and thickness of the pressure vessels subjected to external pressure and other loads causing compressive stresses. The calculations shall be based on accepted pressure vessel shell buckling theory, e.g. DNVGL-RP-C202 and/or DNVGL-CG-0128,

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 243

Part 5 Chapter 7 Section 22

1.2.5 Sloshing loads Simplified sloshing requirements as per Pt.3 Ch.10 Sec.4 for inertia sloshing loads and liquid impact loads shall be satisfied as a minimum requirement. In addition, numerical analyses and/or model testing may be required by the Society if found necessary.

2.1.4 Minimum thickness For pressure vessels, the thickness calculated according to [2.3] shall be considered as a minimum thickness after forming, without any negative tolerance. For pressure vessels, the minimum thickness of shell and heads including corrosion allowance, after forming, shall not be less than 5 mm for carbon-manganese steels and nickel steels, 3 mm for austenitic steels or 7 mm for aluminium alloys. 2.1.5 Corrosion addition Corrosion addition to be considered for the cargo tank is in general according to Sec.4 [2.1.5]. For deck tanks exposed to the weather a corrosion addition of 1.0 mm should be added to the calculated thickness.

2.2 Design conditions 2.2.1 For ultimate (ULS) design conditions, accidental (ALS) design conditions and test conditions, the following shall be considered. Table 1 Design conditions for scantling control of tank structure and support Condition

DC 1 yield check

ULS DC 2 yield check

DC 3 yield and buckling check

Location

Reference

Load components

cylindrical shell

Pt.4 Ch.7 Sec.4 [3.2]

spherical shell

Pt.4 Ch.7 Sec.4 [3.3]

dished ends

Pt.4 Ch.7 Sec.4 [4]

— tank system self-weight

shell in way of support

As described in [2.3.2]

— internal static and dynamic cargo pressure

openings and reinforcements

Pt.4 Ch.7 Sec.4 [6.3]

supports

as described in DC 3 below

swash bulkhead

Pt.3 Ch.10 Sec.2 [2]

— sloshing pressure

tank

as for DC 1

— tank system self-weight

— internal vapour pressure

— max acceleration in way of supports

as for DC 1

— static cargo pressure at 30 degr. inclination — internal vapour pressure

DC 4 buckling check

cylindrical shell

[2.4.1]

spherical shell

[2.4.2]

dished ends

[2.4.3]

— design external pressure — partial filling as relevant — tank system self-weight

ALS

DC 5 forward collision

tank ends and supports

as described in [2.5]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

— static cargo pressure — longitudinal dynamic cargo pressure of 0.5g in forward direction

Page 244

Part 5 Chapter 7 Section 22

Buckling, and shall adequately account for the difference in theoretical and actual buckling stress as a result of plate edge misalignment, ovality and deviation from true circular form over a specified arc or chord length.

Location

Reference

Load components — tank system self-weight

DC 6 aft collision

tank ends and supports

as described in [2.5]

DC 7 flooding condition

flotation supports (tanks located below waterline)

as described in [2.5]

tank and support

[7.1]

tank DC 8 test tank test

— static cargo pressure — longitudinal dynamic cargo pressure of 0.25g in aftward direction — empty tank — external liquid height in cargo hold up to design water line — full tank filled with fresh water

2.3 Scantling due to internal pressure 2.3.1 Minimum plate thickness calculation based on allowable stress The minimum thickness of a cylindrical, conical and spherical shell for pressure loading only shall be determined from the formulae in Pt.4 Ch.7 Sec.4: pressure vessel class I shall apply. The design pressure is given in [1.2.3]. The nominal design allowable stress, f, is given in [2.8.1]. 2.3.2 Longitudinal stresses in the cylindrical shell The longitudinal stress in a cylindrical shell shall be calculated from the following formula:

where:

P0 R t W M

= internal vapour pressure, in MPa, as defined in [1.2.1] = inside radius of shell in mm = minimum net required shell thickness in mm = axial force (tension is positive) due to static and dynamic weight of cargo in N, excluding P0 = longitudinal bending moment in Nm, e.g. due to: — mass loads in a horizontal vessel — eccentricities of the centre of working pressure relative to the neutral axis of the vessel — friction forces between the vessel and a saddle support.

If applicable,

σz is also to be checked for P0 = 0.

Tank test condition need to be taken into account considering p0 the test pressure described in [1.2.8]. The allowable longitudinal stress in the cylindrical tank is given in [2.8.4] against P0 and [2.8.5] for tank test load. The longitudinal stresses are normally to be checked at tank mid-span and at the saddles.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 245

Part 5 Chapter 7 Section 22

Condition

Part 5 Chapter 7 Section 22

2.4 Scantling due to external pressure 2.4.1 Cylindrical shell The cylindrical shell shall be checked so that elastic instability or membrane yield does not occur. The allowable design pressure shall be complied with the requirement in [2.8.2].

TANGENT OF STIFFENER

Figure 2 Effective length of cylinders subject to external pressure — calculation of elastic instability The pressure Pc, in MPa, corresponding to elastic instability of an ideal cylinder, shall be determined from the following formula:

(1)

where n is chosen to minimise Pc which means that the critical pressure is found by an iteration process over the range n, where n > Z. The formula is only applicable when n > Z.

D t

= outside diameter in mm = net thickness of plate, in mm, exclusive of corrosion allowance =

2

E n Z

= Young's modus in N/mm , as defined in Pt.3 Ch.1 Sec.4

L

= effective length between stiffeners in mm, see Figure 2

= integral number of waves (≥ 2) for elastic instability = coefficient equal to 0.5πD/L

— calculation of membrane yield

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 246

2.4.2 Spherical shells The spherical shell shall be checked so that elastic instability or membrane yield does not occur. The allowable design pressure shall be complied with the requirement in [2.8.2]. — calculation of elastic instability The pressure Pc, in MPa, corresponding to elastic instability of a spherical shell, shall be determined from the following formula:

where:

R

= outside radius of sphere in mm.

— calculation of membrane yield For membrane check, the external pressure in MPa causing yield in the sphere will be:

2.4.3 Dished ends Hemispherical ends shall be designed as spherical shells as given in [2.4.2]. Tori spherical ends shall be designed as spherical shells as given in [2.4.2], taking the crown radius as the spherical radius, and in addition, the thickness shall not be less than 1.2 times the thickness required for an end of the same shape subject to internal pressure. Ellipsoidal ends shall be designed as spherical shells as given in [2.4.2], taking the maximum radius of the crown as the equivalent spherical radius, and in addition, the thickness shall not be less than 1.2 times the thickness required for an end of the same shape subject to internal pressure. 2.4.4 Stiffening rings The requirements for scantling of stiffening rings are given in terms of minimum moment of inertia for the 4 member, in mm .

where:

DS P ed

= diameter to the neutral axis of stiffener in mm = external design pressure in MPa defined in [1.2.4].

The length of the shell in mm contributing to the moment of inertia is limited by

Stiffening rings shall extent completely around the circumference of the shell.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 247

Part 5 Chapter 7 Section 22

The pressure Py, in MPa, corresponding to a general membrane yield, shall be determined from the following formula:

2.5.1 The supporting members shall be arranged in such a way as to provide for the maximum imposed loads given in [1.2]. In designs where significant compressive stresses are present, the possibility of buckling shall be investigated. The tank shall be able to expand and contract due to temperature changes without undue restrains. 2.5.2 Where more than two supports are used, the deflection of the hull girder shall be considered. Guidance note: Horizontal tanks supported by saddles should preferably be supported by two saddle supports only. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.5.3 Saddles shall afford bearing over at least 140° of the circumference. 2.5.4 Calculation of stresses in a cylindrical tank shall include: — longitudinal stresses at mid-span and at supports — tangential shear stress at supports and in dished ends, if applicable — circumferential stresses at supports. 2.5.5 For tanks supported in such a way that deflections of the hull transfer significant stresses to the tank, a three-dimensional analysis for the evaluation of the overall structural response of the tank may have to be carried out as required for tanks type B. In that case the same stress limits as given in Sec.20 [4.3] for tanks of type B apply. 2.5.6 The circumferential stresses at supports shall be calculated by a procedure acceptable to the Society for a sufficient number of load cases as defined in [1.2]. The acceptance of calculations based on methods given in recognised standards will be considered from case to case. For horizontal cylindrical tanks made of C-Mn steel supported in saddles, the equivalent stress in stiffening rings shall not exceed the following values if calculated using finite element method:

where:

σvm σall σn σb τ

= von Mises stress = min(0.57Rm;0.85ReH)

2

= normal stress in N/mm in the circumferential direction of the stiffening ring 2

= bending stress in N/mm in the circumferential direction of the stiffening ring 2

= shear stress in N/mm in the stiffening ring.

The buckling strength of the stiffening ring shall be examined.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 248

Part 5 Chapter 7 Section 22

2.5 Supports

The following assumptions may be made when calculating stresses in stiffening rings of horizontal cylindrical tanks: 1)

The stiffening ring may be considered as a circumferential beam formed by web, face plate, doubler plate, if any, and associated shell plating. The effective width of the associated plating may be taken as: —

for cylindrical shells: an effective width. Leff, not larger than given below may be applied

A doubler plate, if any, may be included within that distance. R = mean radius of the cylindrical shell in mm t = shell thickness in mm —

for longitudinal bulkheads, in the case of lobe tanks: the effective width should be determined according to established standards. A value of 20 tb on each side of the web may be taken as a guidance value tb = bulkhead thickness in mm.

2)

The stiffening ring shall be loaded with circumferential forces, on each side of the ring, due to the shear stress, determined by the bi-dimensional shear flow theory from the sheer force of the tank.

3)

For calculation of the reaction forces at the supports the following factors shall be taken into account: —

elasticity of support material, e.g. intermediate layer of wood or similar material

—

change in contact surface between tank and support, and of the relevant reactions, due to: —

thermal shrinkage of tank

—

elastic deformations of tank and support material.

The final distribution of the reaction forces at the supports should not show any tensile forces. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.6 Swash bulkheads 2.6.1 The plates and stiffeners of the swash bulkhead shall as far as practicable be calculated according to Pt.3 Ch.10 Sec.4. In cases where the prescriptive formulas do not apply, alternative equivalent methods may be accepted, provided that the capacity formulation reflects the assumed return period of the load.

2.7 Openings and their reinforcement 2.7.1 The requirements to reinforcements of openings and the dimensioning of attachments related to openings are given in Pt.4 Ch.7 Sec.4. This includes openings related to, e.g. tank domes, sumps and manholes, pipe penetrations. 2.7.2 Scantling control of attachments such as domes and sumps should in principle follow the same calculation procedures as for the main shell of the tank, taking into account the actual dimensions. Effects of openings or penetrations should be included.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 249

Part 5 Chapter 7 Section 22

Guidance note:

2.8.1 Design stresses for allowable code stress assessment For evaluation of the design stresses in the tank, the design equivalent stress shall not exceed the values given below:

σm σL σb σL + σb σm + σb σm + σb + σg σL + σb + σg

≤f ≤ 1.5f ≤ 1.5f ≤ 1.5f ≤ 1.5f ≤ 3.0f ≤ 3.0f

where:

σm σL σb σg f

2

= equivalent von Mises primary general membrane stress, in N/mm 2

= equivalent von Mises primary local membrane stress, in N/mm = equivalent von Mises primary bending stress, in N/mm

2

2

= equivalent von Mises secondary stress, in N/mm , and 2

= allowable stress in N/mm equal to min (Rm/A; ReH/B),

with Rm and ReH as defined in Sec.1. With regard to the stresses σm, σL, σb and σg, the definition of stress categories in Sec.4 [6.1.3] are referred. The values A and B shall have at least the following minimum values: Nickel steels and carbonmanganese steels

Austenitic steels

Aluminium alloys

A

3

3.5

4

B

1.5

1.5

1.5

For certain materials, subject to special consideration by the Society, advantage may be taken of enhanced yield strength and tensile strength at temperatures below -105°C. However, during pressure testing at ambient temperature, [7.1], the specified minimum material properties at the test temperature shall be applied. Allowable stresses for materials other than those referred to in Sec.6, will be subject to approval in each separate case. 2.8.2 Acceptance criteria for buckling strength assessment A membrane stress check shall be carried out for the cylindrical and spherical shells to ensure that elastic instability or membrane yield do not occur under external pressure. The external pressure shall in general not exceed a critical pressure, Pc, which is determined based on an evaluation of the buckling strength of the member, including a general safety factor. The critical pressure, including safety factor, is not allowed to exceed the yield strength of the material. The requirements are given in the following general format: for cylindrical shell

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 250

Part 5 Chapter 7 Section 22

2.8 Acceptance criteria

for cylindrical and spherical shells where:

P Py Ped

= external pressure in MPa corresponding to elastic instability of cylindrical or spherical shell = external pressure in MPa corresponding to membrane yield of the material = external design pressure in MPa as given in [1.2.4].

2.8.3 Acceptance criteria for evaluation of swash bulkhead The capacity formulations given in Pt.3 Ch.10 Sec.4 [3.1] generally apply for the structural members of the swash bulkheads, provided that the bulkhead is not part of the strength of the tank. 2.8.4 Acceptance criteria for longitudinal stresses in the cylindrical shell For design against excessive plastic deformation, σZ according to [2.3.2] shall not exceed 0.8 f e. where:

e

= efficiency factor for welded joints, expressed as a fraction.

The welded joint efficiency factor to be used in the calculation shall be 0.95 when the inspection and the nondestructive testing referred to in Sec.6 [5.6.5] are carried out. This figure may be increased up to 1.0 when account is taken of other considerations, such as the material used, type of joints, welding procedure and type of loading. For process pressure vessels the Society may accept partial non-destructive examinations, but not less than those of Sec.6 [5.6.5], depending on such factors as the material used, the design temperature, the nil ductility transition temperature of the material as fabricated and the type of joint and welding procedure, but in this case an efficiency factor of not more than 0.85 shall be adopted. For special materials the above-mentioned factors shall be reduced, depending on the specified mechanical properties of the welded joint. The value for f, shall be based onvalues for Rm and ReH in cold worked or tempered condition. For design against buckling, the longitudinal compressive stress, σZ shall not exceed:

2.8.5 Acceptance criteria for tank test condition

σt shall at any point not exceed σt ≤ 0.9 · ReH. It should be ensured that any compression stresses in the tank during filling do not cause any instability of the tank shell. In connection with the hydrostatic test described in [7], the membrane stress

2.8.6 Acceptance criteria for accidental condition 2 For the accidental load cases, the nominal equivalent von Mises stress in N/mm shall satisfy the following:

For fine mesh strength assessment with maximum mesh size 50 mm x 50 mm, the acceptance criteria may be increased to 1.5ReH, but not larger than Rm.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 251

Part 5 Chapter 7 Section 22

for spherical shell

3.1 General 3.1.1 A direct finite element strength assessment of the cargo tank is in general not required provided stresses at the supports are properly assessed by other means. For novel designs, large tanks and tank geometries different from the conventional ones such as multi-lobe tanks finite element strength assessment may be required by the Society, see also [1.1.4]. In case a finite element strength assessment of the cargo tank is required the procedure and load cases shall be agreed with the Society. With only two supports, the cargo tank can be modelled independently from the hull structures with consideration of the supports and be evaluated separately. However, in case of more than two (2) supports the analysis shall be based on an integrated cargo tank/hull finite element model in order to determine the interaction forces between the tanks and the supporting ship hull. Loads given in Sec.4 [3] shall be considered and the evaluation shall be based on acceptance criteria given in [2.8]. 3.1.2 Finite element analysis of the ship hull and supports shall be carried out according to Pt.3 Ch.7 and as given in this sub-section. 3.1.3 As a minimum the midship region shall be modelled, but additional analyses for the fore and/or aft cargo hold regions may be required by the Society depending on the actual tank/ship design configuration if fore and aft region deviates significantly from the midship region. 3.1.4 The structure assessment shall be carried out in accordance with the requirement given in Pt.3 Ch.7 Sec.3 [2] and the Society's document DNVGL-CG-0127 Finite element analysis if not otherwise described in this sub section. 3.1.5 Model extent The necessary longitudinal extent of the model will depend on the structural arrangement and the loading conditions. The analysis model shall normally extended over three hold lengths (1+1+1), where the middle tank/hold of the model is used to assess the yield and buckling strength. However, shorter models may be accepted by the Society. The model shall cover the full breadth of the ship in order to account for asymmetric structural layout of the cargo tank/supporting hull structure and asymmetric design load conditions (heeled or other unsymmetrical loading conditions). In order to consider the cargo loads, the cargo tank model shall be integrated into the cargo hold model.

3.2 Loading conditions and design load cases 3.2.1 General Hull girder and local loads according to Pt.3 Ch.4 shall be applied to the model. 3.2.2 Selection of loading conditions At least the following loading conditions shall be examined: — maximum draft with any cargo tank(s) empty — minimum draft with any cargo tank full. Both harbour and sea-going conditions, inclusive any sequential ballast exchange conditions, shall be reviewed. Where the loading conditions specified by the designer are not covered by the standard load cases then these additional loading conditions shall be examined.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 252

Part 5 Chapter 7 Section 22

3 Cargo tank and hull finite element analysis

3.3.1 Evaluation of the analysis shall be made for hull and support structures. 3.3.2 Acceptance criteria for yielding are given in Table 2. Table 2 Coarse mesh permissible yield utilisation factor Structural component

Coarse mesh permissible yield utilization factor,

ship hull structures

λyperm

according to Pt.3 Ch.7 Sec.3 [4] 0.72 (AC-I)

saddle support structures

0.9 (AC-II) 1.0 (AC-III)

Acceptance criteria for buckling are given in Table 3. Table 3 Allowable buckling utilisation factor

η

Structural component ship hull structures

all,

Allowable buckling utilisation factor

according to Pt.3 Ch.8 Sec.1 [3] 0.72 (AC-I)

saddle support structures

0.9 (AC-II) 1.0 (AC-III)

4 Local structure strength analysis 4.1 General 4.1.1 The fine mesh strength assessment shall be carried out in accordance with the rules Pt.3 Ch.7 Sec.4 and DNVGL-CG-0127 Finite element analysis if not otherwise described in this sub section.

4.2 Locations to be checked 4.2.1 The following areas in the midship cargo region shown in the list below shall be investigated with fine mesh analysis. The need for fine mesh analysis of these areas may be determined based on a screening of the actual geometry and the result from the cargo hold analysis. If considered necessary, the Society will require additional locations to be analysed. 4.2.2 Hull structures — Vertical stiffeners on transverse bulkheads connection to inner bottom (when extended to the deck without any support/stringer). 4.2.3 Tank support — Saddle support (when cargo hold model is not sufficient). — Anti floating key.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 253

Part 5 Chapter 7 Section 22

3.3 Acceptance criteria for cargo hold finite element analysis

It is required that the resulting von Mises stresses are not exceeding the allowable membrane values specified in Table 4. These criteria apply to regions where stress concentrations occur due to irregular geometries. Nominal stress shall remain within the limits for cargo hold analysis. Table 4 Maximum allowable membrane stresses for local fine mesh analysis Element stress

Allowable stress

Acceptance criteria

AC-I

AC-II

AC-III

Load components

ULS (S)

ULS (S+D)

ALS (A)

element not adjacent to weld (base material)

1.07 ReH

1.53 ReH

1.84 ReH

element adjacent to weld

0.95 ReH

1.35 ReH

1.62 ReH

tank supports

ship hull structures

according to Pt.3 Ch.7 Sec.4 [4.2]

1)

The maximum allowable stresses are based on the mesh size of 50 mm × 50 mm. Where a smaller mesh size is used, an average von Mises stress calculated over an area equal to the specified mesh size may be used to compare with the permissible stresses.

2)

Average von Mises stress shall be calculated according to Pt.3 Ch.7 Sec.4 [4.2.1].

5 Fatigue strength assessment 5.1 Hull structure 5.1.1 Design criteria The fatigue strength assessment shall be carried out in accordance with Pt.3 Ch.9 and the Society's document DNVGL-CG-0129 Fatigue assessment of ship structures. 5.1.2 Acceptance criteria The hull structure shall be designed to satisfy a minimum design fatigue life of 25 years operation in worldwide environment according to Pt.3 Ch.9 Sec.1.

5.2 Fatigue of cargo tanks 5.2.1 The Society may, in special cases, require fatigue analyses to be carried out. For tanks where the cargo temperature at atmospheric pressure is below -55°C, verification of compliance with [1.1.2] regarding static and dynamic stress may be required. 5.2.2 The analysis shall be carried out for parent material and welded connections at areas where high dynamic stresses or large stress concentrations may be expected, e.g. at tank supports, penetrations and attachments. Static and dynamic membrane and bending stresses shall be determined for use in the fatigue strength assessment, Sec.4 [4.3.3].9. 5.2.3 The procedure for fatigue analysis shall be in accordance with Sec.4 [4.3.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 254

Part 5 Chapter 7 Section 22

4.3 Acceptance criteria

6.1 General 6.1.1 The tanks and the tank supporting structures shall be designed for the accidental loads and design conditions specified in Sec.4 [2.1.4].3 and Sec.4 [3.5], as applicable. 6.1.2 When subjected to the accidental loads specified in Sec.4 [3.5], the stress shall comply with the acceptance criteria specified in [2.8.1] and [2.8.6], modified as appropriate taking into account their lower probability of occurrence.

7 Testing 7.1 Requirements 7.1.1 Each pressure vessel shall be subjected to a hydrostatic test at a pressure measured at the top of the tanks, of not less than 1.5 Po. In no case during the pressure test shall the calculated primary membrane stress at any point exceed 0.9 ReH. To ensure that this condition is satisfied where calculations indicate that this stress will exceed 0.75 times ReH, the prototype test shall be monitored by the use of strain gauges or other suitable equipment in pressure vessels other than simple cylindrical and spherical pressure vessels. 7.1.2 The temperature of the water used for the test shall be at least 30°C above the nil-ductility transition temperature of the material, as fabricated. 7.1.3 The pressure shall be held for two (2) hours per 25 mm of thickness, but in no case less than two (2) hours. 7.1.4 Where necessary for cargo pressure vessels, and with specific approval of the Society, a hydropneumatic test may be carried out under the conditions prescribed in [7.1.1] to [7.1.3]. 7.1.5 Special consideration may be given to the testing of tanks in which higher allowable stresses are used, depending on service temperature. However, the requirements of [7.1.1] shall be fully complied with. 7.1.6 After completion and assembly, each pressure vessel and its related fittings shall be subjected to an adequate tightness test which may be performed in combination with the pressure testing referred to in [7.1.1]. 7.1.7 Pneumatic testing of pressure vessels other than cargo tanks shall only be considered on an individual case basis. Such testing shall only be permitted for those vessels designed or supported such that they cannot be safely filled with water, or for those vessels that cannot be dried and shall be used in a service where traces of the testing medium cannot be tolerated.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 255

Part 5 Chapter 7 Section 22

6 Accidental strength assessment

8.1 General 8.1.1 The tanks shall be manufactured by works approved by the Society for manufacturing of class I pressure vessels. 8.1.2 The workmanship shall comply with the requirements in Pt.4 Ch.7 Sec.7, for class I pressure vessels. Special precautions shall be taken to avoid notches as undercutting, excessive reinforcement, cracks and arc flashes. All welds, nozzle welds included, shall be full penetration welds, unless specially approved for small nozzle diameters.

8.2 Stress relieving 8.2.1 Tanks made of carbon and carbon-manganese steel shall be thermally stress-relieved after welding if the design temperature is below –10°C. 8.2.2 The soaking temperature and holding time shall be as given in Sec.6 [5] and Pt.4 Ch.7 Sec.7 Table 2. For nickel alloy steels and austenitic stainless steel, the requirements for heat treatment will be considered in each case. 8.2.3 In the case of large cargo pressure vessels of carbon or carbon-manganese steel for which it is difficult to perform the heat treatment, mechanical stress relieving by pressurizing may be carried out as an alternative to the heat treatment subject to the following conditions: 1) 2) 3) 4) 5) 6)

Complicated welded pressure vessel parts such as sumps or domes with nozzles, with adjacent shell plates shall be heat treated before they are welded to larger parts of the pressure vessel. The mechanical stress relieving process shall preferably be carried out during the hydrostatic pressure test required by [7], by applying a higher pressure than the test pressure required by [7]. The pressurizing medium shall be water. For the water temperature, [7] applies. Stress relieving shall be performed while the tank is supported by its regular saddles or supporting structure or, when stress relieving cannot be carried out on board, in a manner which will give the same stresses and stress distribution as when supported by its regular saddles or supporting structure. The maximum stress relieving pressure shall be held for two hours per 25 mm of thickness but in no case less than two hours. The upper limits placed on the calculated stress levels during stress relieving shall be the following: — equivalent general primary membrane stress: 0.9 ReH — equivalent stress composed of primary bending stress plus membrane stress: 1.35 ReH where ReH is the specific lower minimum yield stress or 0.2% proof stress at test temperature of the steel used for the tank.

7)

Strain measurements will normally be required to prove these limits for at least the first tank of a series of identical tanks built consecutively. The location of strain gauges shall be included in the mechanical stress relieving procedure.

8)

The test procedure should demonstrate that a linear relationship between pressure and strain is achieved at the end of the stress relieving process when the pressure is raised again up to the design pressure.

9)

High stress areas in way of geometrical discontinuities such as nozzles and other openings shall be checked for cracks by dye penetrant or magnetic particle inspection after mechanical stress relieving. Particular attention in this respect shall be given to plates exceeding 30 mm in thickness.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 256

Part 5 Chapter 7 Section 22

8 Manufacture and workmanship

11) Mechanical stress relieving cannot be substituted for heat treatment of cold formed parts of tanks if the degree of cold forming exceeds the limit above which heat treatment is required. 12) The thickness of the shell and heads of the tank shall not exceed 40 mm. Higher thicknesses may be accepted for parts which are thermally stress relieved. 13) Local buckling shall be guarded against particularly when tori-spherical heads are used for tanks and domes. 14) The procedure for mechanical stress relieving shall be submitted beforehand to the Society for approval.

8.3 Manufacture 8.3.1 Out of roundness shall not exceed the limit given in Pt.4 Ch.7 Sec.8 [2.3.4]. 8.3.2 Irregularities in profile shall not exceed the limit given in Pt.4 Ch.7 Sec.7 [2.3.5], or 0.2% of D, whichever is the greater, with a maximum equal to the plate thickness. D is the diameter of the shell. Measurements shall be made from a segmental circular template having the design inside or outside radius, and having a chord length corresponding to the arc length obtained from Figure 3. For spheres, L is one half the outside diameters. For shells under internal pressure, the chord length need not exceed 0.17 D.

Figure 3 Arc length for determining deviation for true form

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 257

Part 5 Chapter 7 Section 22

10) Steels which have a ratio of yield stress to ultimate tensile strength greater than 0.8 shall generally not be mechanically stress relieved. If, however, the yield stress is raised by a method giving high ductility of the steel, slightly higher rates may be accepted upon consideration in each case.

Part 5 Chapter 7 Section 22

8.4 Marking 8.4.1 The required marking of the pressure vessel shall be achieved by a method that does not cause unacceptable local stress raisers.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 258

1 General 1.1 Design basis 1.1.1 Hull design The hull design shall be carried out according to main class requirements in Pt.3 of the rules. In addition, the present rules for liquefied gas carriers, this section give additional design requirements for liquefied gas carriers with membrane tanks. 1.1.2 The design basis for membrane containment systems is that thermal and other expansion or contraction is compensated for without undue risk of losing the tightness of the membrane. 1.1.3 A systematic approach based on analysis and testing shall be used to demonstrate that the system will provide its intended function in consideration of the events identified in service as specified in [1.2.1]. 1.1.4 If the cargo temperature at atmospheric pressure is below -10°C a complete secondary barrier shall be provided as required in Sec.4 [2.3]. The secondary barrier shall be designed according to Sec.4 [2.4]. 1.1.5 The design vapour pressure Po shall not normally exceed 0.025 MPa. If the hull scantlings are increased accordingly and consideration is given, where appropriate, to the strength of the supporting thermal insulation, Po may be increased to a higher value, but less than 0.07 MPa. 1.1.6 The definition of membrane tanks does not exclude designs such as those in which non-metallic membranes are used or in which membranes are included or incorporated into the thermal insulation. Such designs require, however, special consideration by the Society. 1.1.7 The thickness of the membranes shall not normally exceed 10 mm. 1.1.8 The circulation of inert gas throughout the primary insulation space and the secondary insulation space, in accordance with Sec.9 [2], shall be sufficient to allow for effective means of gas detection. 1.1.9 The structural analysis of the hull shall be performed in accordance with this section and the rules for hull structure given in Pt.3. Special attention is, however, to be paid to deflections of the hull and their compatibility with the membrane and associated insulation. Guidance note: Methods for strength analysis of hull structure in liquefied gas carriers with membrane tanks are given in DNVGL-CG-0136 Liquefied gas carriers with membrane tanks. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Design considerations 1.2.1 Potential incidents that could lead to loss of fluid tightness over the life of the membranes shall be evaluated. These include, but are not limited to:

.1

ultimate design events:

.1 .2 .3

tensile failure of membranes compressive collapse of thermal insulation thermal ageing

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 259

Part 5 Chapter 7 Section 23

SECTION 23 DESIGN WITH MEMBRANE TANKS

.2

loss of attachment of membranes to thermal insulation system structural integrity of internal structures and their supporting structures, and failure of the supporting hull structure.

fatigue design events:

.1 .2 .3 .4 .3

loss of attachment between thermal insulation and hull structure

fatigue of membranes including joints and attachments to hull structure fatigue cracking of thermal insulation fatigue of internal structures and their supporting structures, and fatigue cracking of inner hull leading to ballast water ingress.

accident design events:

.1 .2 .3 .4

accidental mechanical damage (such as dropped objects inside the tank while in service) accidental over pressurization of thermal insulation spaces accidental vacuum in the tank, and water ingress through the inner hull structure.

Designs where a single internal event could cause simultaneous or cascading failure of both membranes are unacceptable. 1.2.2 The necessary physical properties, i.e. mechanical, thermal, chemical, etc. of the materials used in the construction of the cargo containment system shall be established during the design development in accordance with [1.1.3]. 1.2.3 As basis for hull material selection temperature analyses shall be carried out as given in Sec.4 [3.3.4], and the hull material selected according to Sec.5 [1.1]. 1.2.4 For corrosion additions of the hull structure, see Pt.3 Ch.3 Sec.3.

1.3 Arrangement of cargo area 1.3.1 A double bottom, double side, trunk deck and cofferdam bulkhead shall be arranged to facilitate the support of the membrane system. The distance of bottom line to the tank and the distance of shell to the inner side shall comply with Sec.2 [4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 260

Part 5 Chapter 7 Section 23

.4 .5 .6 .7

Part 5 Chapter 7 Section 23

1.3.2 Definition

Figure 1 Nomenclature for a midship section

1.4 Loads 1.4.1 Particular consideration shall be given to the possible loss of tank integrity due to either an overpressure in the interbarrier space, a possible vacuum in the cargo tank, sloshing effects, hull vibration effects, or any combination of these events. 1.4.2 Environmental loads Design loads according to the rules Pt.3 Ch.4 are applicable for all parts of hull structure including inner hull and transverse bulkhead. In addition loads from the cargo, as given in Sec.4 [3.3.2], shall be applied when analyzing local strength of plates and stiffeners of the parts of inner hull supporting the membrane tanks as required in [2.2]. For cargo hold FE analysis, dynamic loads defined in Pt.3 Ch.4 shall be applied. 1.4.3 Sloshing loads When partial tank filling is contemplated, the risk of significant loads due to sloshing induced by any of the ship motions shall be considered.

.1 .2

Inertia sloshing loads as described in the rules, Pt.3 Ch.10 Sec.4, shall be considered as a minimum. In order to determine liquid impact loads for membrane tanks special tests and/or calculations shall be carried out as described in the Society's document DNVGL-CG-0158 Sloshing analysis of LNG

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 261

Guidance note: In order to avoid insulation system damage from high liquid impact loads the system may either be strengthened (if possible) or be subject to operational limitation in the form of: —

tank filling restrictions, or if this is not an option

—

maximum operating limits may be specified e.g. in terms of ship headings and significant wave height. Such restrictions are mostly relevant for loading/offloading at offshore export/import terminals. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.5 Structural analysis 1.5.1 Structural analyses and/or testing for the purpose of determining the ultimate strength and fatigue assessments of the cargo containment and associated structures, e.g. structures as defined in Sec.4 [2.7], shall be performed. The structural analysis shall provide the data required to assess each failure mode that has been identified as critical for the cargo containment system. 1.5.2 Structural analyses of the hull shall take into account the internal pressure as indicated in Sec.4 [3.3.2]. Special attention shall be paid to deflections of the hull and their compatibility with the membrane and associated thermal insulation. 1.5.3 The analyses referred to in [1.5.1] and [1.5.2] shall be based on the particular motions, accelerations and response of ships and cargo containment systems.

2 Ultimate strength assessment 2.1 General 2.1.1 The structural resistance of every critical component, subsystem, or assembly shall be established, in accordance with [1.1.3], for in-service conditions. 2.1.2 The choice of strength acceptance criteria for the failure modes of the cargo containment system, its attachments to the hull structure and internal tank structures, shall reflect the consequences associated with the considered mode of failure.

2.2 Local scantling of inner hull 2.2.1 The scantling of inner hull plates and stiffeners shall meet the requirements described in Pt.3 Ch.6 as minimum. In addition, they shall comply with below requirement taking into account the internal pressure as indicated in Sec.4 [3.3.2] and the specified appropriate requirements for sloshing load as defined in Sec.4 [3.4.4]. 2.2.2 Plating The net local scantlings in mm of inner hull plating supporting the membrane tanks shall satisfy the following:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 262

Part 5 Chapter 7 Section 23

membrane tanks. Result of tests and/or calculations available from previous vessel may be used when the configuration of the tank/ship is considered to be identical.

αp

= correction factor for the panel aspect ratio calculated as follows but not to be taken greater than 1.0

a b Peq

= length of plate panel in mm, Pt.3 Ch.3 Sec.7 [2.1.1]

Ca

= permissible bending stress coefficient for plate taken equal to:

= breadth of plate panel in mm, Pt.3 Ch.3 Sec.7 [2.1.1] 2

= cargo tank pressure in kN/mm as given in Sec.4 [3.3.2]

where

αa, βa Ca-max

= coefficient as defined for AC-II in Pt.3 Ch.6 Sec.4 Table 1

σhg

= hull girder bending stress, in N/mm , calculated at the load calculation point as defined in Pt.3 Ch.3 Sec.7 [2.2]

= maximum permissible bending stress coefficient as defined for AC-II in Pt.3 Ch.6 Sec.4 Table 1 2

= max[|σsw-i + σwv-i|; |σsw-i + 0.5σwv-i| + σwh] 2

σsw-i

= longitudinal stress, in N/mm , induced by still water bending moment as defined in Pt.3 Ch.5 Sec.3 [4.1.1]

σwv-i

= longitudinal stress, in N/mm , induced by vertical wave bending moment, sagging or hogging

2

=

, where vertical wave bending moments, Mwv-i, as defined in Pt.3 Ch.4 Sec.4 [3.1.1]

σwh

2

= longitudinal stress, in N/mm , induced by horizontal wave bending moment =

, where horizontal wave bending moment, Mwh, as defined in Pt.3 Ch.4 Sec.4 [3.3.1]

2.2.3 Section modulus for stiffeners 3 The net section modulus in cm of stiffeners on inner hull supporting the membrane tanks shall satisfy the following:

where:

fu lbdg

= factor for unsymmetrical profiles, as given in Pt.3 Ch.6 Sec.5 [1.1.2] = effective bending span in m as defined in Pt.3 Ch.3 Sec.7

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 263

Part 5 Chapter 7 Section 23

where:

= permissible bending stress coefficient for stiffener taken equal to:

where:

αs , βs Cs-max

= coefficients as defined for AC-II in Pt.3 Ch.6 Sec.5 Table 4

σhg

= hull girder compressive stress, in N/mm , calculated at the load calculation point as defined in Pt.3 Ch.3 Sec.7 [3.2]

= maximum permissible bending stress coefficient as defined for AC-II in Pt.3 Ch.6 Sec.5 Table 4 2

= max[|σsw-s + σwv-s|; |σsw-s + 0.5σwv-s| + σwh], for z ≥ zn = max[|σsw-h + σwv-h|; |σsw-h + 0.5σwv-h| + σwh], for z < zn

σsw-s , σsw-h

2

= longitudinal stress, in N/mm , induced by sagging/hogging still water bending moment respectively = as σsw-i given in [2.2.2]

σwv-s , σwv-h

2

= longitudinal stress, in N/mm , induced by vertical sagging/hogging wave bending moment respectively = as σwv-i given in [2.2.2]

zn

= vertical distance from BL to horizontal neutral axis, see Pt.3 Ch.1 Sec.4.

σwh as given in [2.2.2]

s fbdg

= stiffener spacing in mm = bending moment factor as defined in Pt.3 Ch.6 Sec.5 Table 5. For stiffeners with fixity deviating from the ones included in Pt.3 Ch.6 Sec.5 Table 5 with complex load pattern, or being part of a grillage, the requirement in Pt.3 Ch.6 Sec.5 [1.2] applies.

2.2.4 Effect of impact sloshing loads Sloshing impact loads acting on the containment system inside the cargo tanks have to be transferred into the supporting hull structure, i.e. the inner hull supporting the insulation system. It shall be ensured that the inner hull structure has the sufficient stiffness and strength to carry the sloshing loads. The hull structure assessment shall be carried out in two steps in order to make sure that:

.1

The stiffness of the inner hull plates is sufficient to provide adequate support for the containment system.

.2

The strength of the inner hull longitudinals (stiffeners) is sufficient to carry the sloshing loads without suffering large permanent deformations.

Procedures for such assessments are given in DNVGL-CG-0158 Sloshing analysis of LNG membrane tanks. Guidance note: Sloshing impact loads are mostly relevant for localised areas as knuckles and tank corners, e.g. in chamfer knuckles at transverse bulkheads. However, the extent of these areas will be increased if the normal filling restrictions recommended by the system designer have been relaxed. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.5 Connection area Connection area of stiffeners shall be according to the rules Pt.3 Ch.6 Sec.7. The design pressure load p may then be taken according to Sec.4 [3.3.2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 264

Part 5 Chapter 7 Section 23

Cs

3.1 Cargo hold analysis 3.1.1 Model extent Cargo hold structural strength analysis is mandatory within the cargo area and shall include the aft bulkhead of the aftmost cargo hold and the collision bulkhead, of the forward hold. Longitudinal members and scarfing structures in the deck house between trunk deck and upper deck shall in addition be included in the evaluation along with longitudinal members and scarfing structures in engine room and the cargo area. 3.1.2 Loading conditions The following loading conditions shall be examined: — maximum draft with any cargo tank(s) empty — minimum draft with any cargo tank full. Both harbour and sea-going conditions, inclusive any sequential ballast exchange conditions, shall be reviewed. The filling condition of the ballast tank under the considered tank should be taken into account. 3.1.3 Acceptance Criteria Acceptance criteria for yielding are given in the rules Pt.3 Ch.7 Sec.3 [4.2]. Acceptance criteria for buckling are given in the rules Pt.3 Ch.8 Sec.1 [3.3].

3.2 Local fine mesh analysis 3.2.1 Locations to be checked Double hull longitudinals with brackets subjected to large deformations. .1 Fine mesh analysis shall be carried out for the connections of side and bottom longitudinal stiffeners and adjoining structures of the cofferdam bulkhead. The adjoining structures at the cofferdam bulkheads include the structural members in way of the bulkhead, the partial double side girders and bottom girders, if any.

.2

Other locations. Additional locations may be required for fine mesh analysis in case the results of cargo hold analysis is not sufficient to judge the area, i.e. due to the poor shape of element.

3.2.2 Acceptance criteria Acceptance criteria for stress results for local structural analysis are given in Pt.3 Ch.7 Sec.4 [4.2].

4 Fatigue strength assessment 4.1 General 4.1.1 Fatigue analysis shall be carried out for structures inside the tank, i.e. pump towers, and for parts of membrane and pump tower attachments, where failure development cannot be reliably detected by continuous monitoring.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 265

Part 5 Chapter 7 Section 23

3 Finite element strength analysis for hull

.1 .2

the significance of the structural components with respect to structural integrity, and the availability for inspection.

4.2 Fatigue assessment for hull 4.2.1 The ship hull shall be designed to satisfy a minimum design fatigue life of 25 years operation in worldwide environment according to Pt.3 Ch.9 Sec.1 with damage factor CW ≤ 1.0. 4.2.2 Plates in inner hull structures acting as supports for the membrane system where cracks along the plate boundaries can cause leakage into the insulation system, i.e. plate welds to stiffeners and frames/ 8 girders in the ballast tanks, shall be designed to satisfy a design fatigue life with 10 wave encounters in North Atlantic operation. 4.2.3 Loading conditions For fatigue assessment, the following two loading conditions shall normally be taken into account: — fully loaded condition, departure — normal ballast condition, departure. 4.2.4 Locations to be checked The fatigue strength calculations shall be carried out for following locations as a minimum. Other locations subject to high dynamic stress and/or high stress concentration may be required for fatigue analysis by the Society: — — — — —

lower and upper hopper knuckle connections forming boundary of inner skin amidships inner bottom connection to transverse cofferdam bulkhead double hull side stringer connection to transverse cofferdam bulkhead liquid dome opening and coaming connection to deck, if applicable termination of aft end of no.1 inner longitudinal bulkhead, if applicable.

Special consideration regarding specified scope may be given for well proven detail designs.

4.3 Fatigue evaluation of membrane system 4.3.1 For structural elements for which it can be demonstrated by tests and/or analyses that a crack will not develop to cause simultaneous or cascading failure of both membranes, shall satisfy the fatigue and fracture mechanics requirements in Sec.4 [4.3.3] .7 with Cw≤ 0.5. 4.3.2 Structural elements subject to periodic inspection, and where an unattended fatigue crack can develop to cause simultaneous or cascading failure of both membranes, shall satisfy the fatigue and fracture mechanics requirements stated in Sec.4 [4.3.3] .8, with Cw ≤ 0.5. 4.3.3 Structural element not accessible for in-service inspection, and where a fatigue crack can develop without warning to cause simultaneous or cascading failure of both membranes, shall satisfy the fatigue and fracture mechanics requirements stated in Sec.4 [4.3.3] .9, with Cw ≤ 0.1. Guidance note: All non-inspectable failures that may lead to damage to the primary and secondary barrier, e.g. pump tower supports, should be analysed in accordance with [4.3.3]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 266

Part 5 Chapter 7 Section 23

4.1.2 The fatigue calculations shall be carried out in accordance with Sec.4 [3.3.3], with relevant requirements depending on:

5.1 General 5.1.1 The containment system and the supporting hull structure shall be designed for the accidental loads specified in Sec.4 [3.5]. These loads need not be combined with each other or with environmental loads. 5.1.2 Additional relevant accident scenarios shall be determined based on a risk analysis. Particular attention shall be paid to securing devices inside of tanks.

6 Testing 6.1 Design development testing 6.1.1 The design development testing required in [1.1.3] shall include a series of analytical and physical models of both the primary and secondary barriers, including corners and joints, tested to verify that they will withstand the expected combined strains due to static, dynamic and thermal loads. This will culminate in the construction of a prototype scaled model of the complete cargo containment system. Testing conditions considered in the analytical and physical models shall represent the most extreme service conditions the cargo containment system will be likely to encounter over its life. Proposed acceptance criteria for periodic testing of secondary barriers required in Sec.4 [2.4.2] may be based on the results of testing carried out on the prototype-scaled model. 6.1.2 The fatigue performance of the membrane materials and representative welded or bonded joints in the membranes shall be determined by tests. The ultimate strength and fatigue performance of arrangements for securing the thermal insulation system to the hull structure shall be determined by analyses or tests.

6.2 Testing for newbuilding 6.2.1 In ships fitted with membrane cargo containment systems, all tanks and other spaces that may normally contain liquid and are adjacent to the hull structure supporting the membrane, shall be hydrostatically tested. 6.2.2 All hold structures supporting the membrane shall be tested for tightness before installation of the cargo containment system. 6.2.3 Pipe tunnels and other compartments that do not normally contain liquid need not be hydrostatically tested.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 267

Part 5 Chapter 7 Section 23

5 Accidental strength assessment

1 Integral tanks 1.1 Design basis 1.1.1 Integral tanks that form a structural part of the hull and are affected by the loads that stress the adjacent hull structure shall comply with the following:

.1

the design vapour pressure Po as defined in Sec.4 [1.1.2] shall normally not exceed 0.025 MPa. If the hull scantlings are increased accordingly, Po may be increased to a higher value, but less than 0.07 MPa

.2

integral tanks may be used for products if the boiling point of the cargo is not below -10°C. A lower temperature may be accepted by the Society subject to special consideration, but in such cases a complete secondary barrier shall be provided

.3

products required by Sec.19 to be carried in type 1G ships shall not be carried in integral tanks. 3

1.1.2 Tanks for cargoes with density below 1000 kg/m shall as a minimum have scantlings based on the density of seawater. 3

Tanks for cargoes with density above 1000 kg/m , see Pt.3 Ch.4 Sec.6. 1.1.3 For materials other than normal strength steel, the minimum thickness requirements will be considered in each case.

1.2 Structural analysis 1.2.1 The structural analysis of integral tanks shall be in accordance with Pt.3 Ch.7. 1.2.2 Ultimate design condition, ULS The tank boundary scantlings shall meet the requirements for deep tanks, taking into account the .1 internal pressure as given in Sec.4 [3.3.2].

.2

For integral tanks, allowable stresses as given for hull structure in Pt.3 shall be applied.

1.2.3 Accidental design condition, ALS The tanks and the tank supports shall be designed for the accidental loads specified in Sec.4 [2.1.4].3 .1 and Sec.4 [3.5], as relevant.

.2

When subjected to the accidental loads specified in Sec.4 [3.5], the stress shall comply with the acceptance criteria specified in [1.2.2], modified as appropriate, taking into account their lower probability of occurrence.

1.3 Testing 1.3.1 All integral tanks shall be hydrostatically or hydro-pneumatically tested. The test shall be performed so that the stresses approximate, as far as practicable, to the design stresses and that the pressure at the top of the tank corresponds at least to the MARVS.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 268

Part 5 Chapter 7 Section 24

SECTION 24 OTHER CARGO TANK DESIGNS

2.1 Design basis 2.1.1 Semi-membrane tanks are non-self-supporting tanks when in the loaded condition and consist of a layer, parts of which are supported through thermal insulation by the adjacent hull structure, whereas the rounded parts of this layer connecting the above-mentioned supported parts are designed also to accommodate thermal expansion and/or contraction as well as deformations due to the loads given in Pt.3 Ch.4. 2.1.2 The design vapour pressure Po shall not normally exceed 0.025 MPa. If the hull scantlings are increased accordingly, and consideration is given, where appropriate, to the strength of the supporting thermal insulation, Po may be increased to a higher value, but less than 0.07 MPa. 2.1.3 For semi-membrane tanks the relevant requirements in this section for independent tanks or for membrane tanks shall be applied as appropriate. 2.1.4 Structural analysis shall be performed in accordance with the requirements for membrane tanks or independent tanks, as appropriate, taking into account the internal pressure as indicated in Sec.4 [3.3.2]. 2.1.5 In the case of semi-membrane tanks that comply in all respects with the requirements applicable to type B independent tanks, except for the type of support, the Society may accept a partial secondary barrier on a case by case basis.

3 Cargo containment systems of novel configuration 3.1 Limit state design for novel concepts 3.1.1 Application Cargo containment systems that are of a novel configuration that cannot be designed using Sec.20 to [2] shall be designed using this sub section and Sec.4, as applicable. Cargo containment system design according to this sub section shall be based on the principles of limit state design which is an approach to structural design that can be applied to established design solutions as well as novel designs. This more generic approach maintains a level of safety similar to that achieved for known containment systems as designed using Sec.20 to [2]. 3.1.2 Limit states Limit state designs is a systematic approach where each structural element is evaluated with respect .1 to possible failure modes related to the design conditions identified in Sec.4 [2.1.4]. A limit state can be defined as a condition beyond which the structure, or part of a structure, no longer satisfies the requirements.

.2

For each failure mode, one or more limit states may be relevant. By consideration of all relevant limit states, the limit load for the structural element is found as the minimum limit load resulting from all the relevant limit states. The limit states are divided into the three following categories:

.1

ultimate limit states (ULS), which correspond to the maximum load-carrying capacity or, in some cases, to the maximum applicable strain or deformation; under intact (undamaged) conditions

.2

fatigue limit states (FLS), which correspond to degradation due to the effect of time varying cyclic loading

.3

accident limit states (ALS), which concern the ability of the structure to resist accidental situations.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 269

Part 5 Chapter 7 Section 24

2 Semi-membrane tanks

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 270

Part 5 Chapter 7 Section 24

3.1.3 The procedure and relevant design parameters of the limit state design shall comply with the standard for the use of limit state methodologies in the design of cargo containment systems of novel configuration (LSD Standard), as set out in App.B.

1 General 1.1 Introduction 1.1.1 The guidance given in this appendix is in addition to the requirements of Sec.4 [5.1.1], where applicable to non-metallic materials. 1.1.2 The manufacture, testing, inspection and documentation of non-metallic materials should in general comply with recognized standards, and with the specific requirements in the rules, as applicable. 1.1.3 When selecting a non-metallic material, the designer should ensure that it has properties appropriate to the analysis and specification of the system requirements. A material can be selected to fulfil one or more requirements. A wide range of non-metallic materials may be considered. Therefore, the section below on material selection criteria cannot cover every possibility and should be considered as guidance.

2 Material selection criteria 2.1 Non-metallic materials 2.1.1 Non-metallic materials may be selected for use in various parts of liquefied gas carrier cargo systems based on consideration of the following basic properties:

.1 .2 .3 .4

insulation - the ability to limit heat flow load bearing - the ability to contribute to the strength of the containment system tightness - the ability to provide liquid and vapour tight barriers joining - the ability to be joined, e.g. by bonding, welding or fastening.

2.1.2 Additional considerations may apply depending on the specific system design.

3 Property of materials 3.1 General 3.1.1 Flexibility of insulating material is the ability of an insulating material to be bent or shaped easily without damage or breakage. 3.1.2 Loose fill material is a homogeneous solid generally in the form of fine particles, such as a powder or beads, normally used to fill the voids in an inaccessible space to provide an effective insulation. 3.1.3 Nanomaterial is a material with properties derived from its specific microscopic structure. 3.1.4 Cellular material is a material type containing cells that are either open, closed or both and which are dispersed throughout its mass. 3.1.5 Adhesive material is a product that joins or bonds two adjacent surfaces together by an adhesive process.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 271

Part 5 Chapter 7 Appendix A

APPENDIX A NON-METALLIC MATERIALS

4 Material selection and testing requirements 4.1 Material specification 4.1.1 When the initial selection of a material has been made, tests should be conducted to validate the suitability of this material for the use intended. 4.1.2 The material used should clearly be identified and the relevant tests should be fully documented. 4.1.3 Materials should be selected according to their intended use. They should:

.1 .2 .3 .4

be compatible with all the products that may be carried not be contaminated by any cargo nor react with it not have any characteristics or properties affected by the cargo, and be capable to withstand thermal shocks within the operating temperature range.

4.2 Material testing 4.2.1 The tests required for a particular material depend on the design analysis, specification and intended duty. The list of tests below is for illustration. Any additional tests required, for example in respect of sliding, damping and galvanic insulation, should be identified clearly and documented. Materials selected according to [4.1] of this appendix should be tested further according to the following: Function

Load bearing structural

Insulation

mechanical tests

X

tightness tests thermal tests

Tightness

Joining X

X X

Thermal shock testing should submit the material and/or assembly to the most extreme thermal gradient it will experience when in service. 4.2.2 Inherent properties of materials Tests should be carried out to ensure that the inherent properties of the material selected will not have .1 any negative impact in respect of the use intended.

.2

For all selected materials, the following properties should be evaluated:

.1 .2 .3

density - example standard ISO 845 linear coefficient of thermal expansion (LCTE) - example standard ISO 11359 across the widest specified operating temperature range. However, for loose fill material the volumetric coefficient of thermal expansion (VCTE) should be evaluated, as this is more relevant.

Irrespective of its inherent properties and intended duty, all materials selected should be tested for the design service temperature range down to 5°C below the minimum design temperature, but not lower than -196°C.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 272

Part 5 Chapter 7 Appendix A

3.1.6 Other materials are materials that are not characterized in this section of the code and should be identified and listed. The relevant tests used to evaluate the suitability of material for use in the cargo system should be identified and documented.

Each property evaluation test should be performed in accordance with recognized standards. Where there are no such standards, the test procedure proposed should be fully detailed and submitted to the Society for acceptance. Sampling should be sufficient to ensure a true representation of the properties of the material selected.

4.2.3 Mechanical tests The mechanical tests should be performed in accordance with the following: 1. Mechanical tests

Load bearing structural ISO 527 ISO 1421

tensile

ISO 3346 ISO 1926

shearing

ISO 4587 ISO 3347 ISO 1922 ISO 6237

compressive

ISO 604 ISO 844 ISO 3132

bending

ISO 3133 ISO 14679

creep

ISO 7850

.2

If the chosen function for a material relies on particular properties such as tensile, compressive and shear strength, yield stress, modulus or elongation, these properties should be tested to a recognized standard. If the properties required are assessed by numerical simulation according to a high order behaviour law, the testing should be performed to the satisfaction of the Society.

.3

Creep may be caused by sustained loads, for example cargo pressure or structural loads. Creep testing should be conducted based on the loads expected to be encountered during the design life of the containment system.

4.2.4 Tightness tests The tightness requirement for the material should relate to its operational functionality. .1

.2

Tightness tests should be conducted to give a measurement of the material's permeability in the configuration corresponding to the application envisaged, e.g. thickness and stress conditions using the fluid to be retained, e.g. cargo, water vapour or trace gas.

.3

The tightness tests should be based on the tests indicated as examples in the following: Tightness tests

porosity/permeability

Tightness ISO 15106 ISO 2528 ISO 2782

4.2.5 Thermal conductivity tests Thermal conductivity tests should be representative of the lifecycle of the insulation material so its .1 properties over the design life of the cargo system can be assessed. If these properties are likely to deteriorate over time, the material should be aged as best possible in an environment corresponding

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 273

Part 5 Chapter 7 Appendix A

.4

.2

Requirements for the absolute value and acceptable range of thermal conductivity and heat capacity should be chosen taking into account the effect on the operational efficiency of the cargo containment system. Particular attention should also be paid to the sizing of the associated cargo handling system and components such as safety relief valves plus vapour return and handling equipment.

.3

Thermal tests should be based on the tests indicated as examples in the following or their equivalents: Thermal tests

thermal conductivity heat capacity

Insulating ISO 8301 ISO 8302 x

4.2.6 Physical tests In addition to the requirements of Sec.4 [5.1.2].3] and Sec.4 [5.1.3].2] guidance and information on .1 some of the additional physical tests that may be considered are listed as follows: Physical tests

Flexible insulating

particle size

Loose fill

Nanomaterial

Adhesive

X

closed cells content absorption/desorption

Cellular

ISO 4590 ISO 12571

X

absorption/desorption

ISO 2896 X ISO 2555 ISO 2431

viscosity open time

ISO 10364

thixotropic properties

X

hardness

ISO 868

.2

Requirements for loose fill material segregation should be chosen considering its potential adverse effect on the material properties as density and thermal conductivity, when subjected to environmental variations such as thermal cycling and vibration.

.3

Requirements for materials with closed cell structures should be based on its possible impact on gas flow and buffering capacity during transient thermal phases.

.4

Similarly, adsorption and absorption requirements should take into account the potential adverse effect an uncontrolled buffering of liquid or gas may have on the system.

5 Quality assurance and quality control (QA/QC) 5.1 General 5.1.1 Once a material has been selected, after testing as outlined in [4], a detailed quality assurance/quality control (QA/QC) programme should be applied to ensure the continued conformity of the material during installation and service. This programme should consider the material starting from the manufacturer's quality manual (QM) and then follow it throughout the construction of the cargo system.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 274

Part 5 Chapter 7 Appendix A

to its lifecycle, for example operating temperature, light, vapour and installation, e.g. packaging, bags, boxes.

5.1.3 Where powder or granulated insulation is produced, arrangements should be made to prevent compacting of the material due to vibrations.

5.2 QA/QC during component manufacture The QA/QC programme in respect of component manufacture should include, as a minimum but not limited to, the following items. 5.2.1 Component identification For each material, the manufacturer should implement a marking system to clearly identify the .1 production batch. The marking system should not interfere, in any way, with the properties of the product.

.2

The marking system should ensure complete traceability of the component and should include:

.1 .2 .3 .4 .5

date of production and potential expiry date manufacturer's references reference specification reference order, and when necessary, any potential environmental parameters to be maintained during transportation and storage.

5.2.2 Production sampling and audit method Regular sampling is required during production to ensure the quality level and continued conformity of .1 a selected material.

.2

The frequency, the method and the tests to be performed should be defined in QA/QC programme; for example, these tests will usually cover, inter alia, raw materials, process parameters and component checks.

.3

Process parameters and results of the production QC tests should be in strict accordance with those detailed in the QM for the material selected.

.4

The objective of the audit method as described in the QM shall control the repeatability of the process and the efficacy of the QA/QC programme.

.5

During auditing, auditors should be provided with free access to all production and QC areas. Audit results should be in accordance with the values and tolerances as stated in the relevant QM.

6 Bonding and joining process requirement and testing 6.1 Bonding procedure qualification 6.1.1 The bonding procedure specification and qualification test should be defined in accordance with recognized standards. 6.1.2 The bonding procedures should be fully documented before work commences to ensure the properties of the bond are acceptable.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 275

Part 5 Chapter 7 Appendix A

5.1.2 The QA/QC programme should include the procedure for fabrication, storage, handling and preventive actions to guard against exposure of a material to harmful effects. These may include, for example, the effect of sunlight on some insulation materials or the contamination of material surfaces by contact with personal products such as hand creams. The sampling methods and the frequency of testing in the QA/QC programme should be specified to ensure the continued conformity of the material selected throughout its production and installation.

.1 .2 .3 .4 .5 .6 .7

surface preparation materials storage and handling prior to installation covering-time open-time mixing ratio, deposited quantity environmental parameters as temperature and humidity, and curing pressure, temperature and time.

6.1.4 Additional requirements may be included as necessary to ensure acceptable results. 6.1.5 The bonding procedures specification should be validated by an appropriate procedure qualification testing programme.

6.2 Personnel qualifications 6.2.1 Personnel involved in bonding processes should be trained and qualified to recognized standards. 6.2.2 Regular tests should be made to ensure the continued performance of people carrying out bonding operations to ensure a consistent quality of bonding.

7 Production bonding tests and controls 7.1 Destructive testing During production, representative samples should be taken and tested to check that they correspond to the required level of strength as required for the design.

7.2 Non-destructive testing 7.2.1 During production, tests which are not detrimental to bond integrity should be performed using an appropriate technique such as:

.1 .2 .3

visual examination internal defects detection, e.g. acoustic, ultrasonic and shear test, and local tightness testing.

7.2.2 If the bonds have to provide tightness as part of their design function, a global tightness test of the cargo containment system should be completed after the end of the erection in accordance with the designer's and QA/QC programme. 7.2.3 The QA/QC standards should include acceptance standards for the tightness of the bonded components when built and during the lifecycle of the containment system.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 276

Part 5 Chapter 7 Appendix A

6.1.3 The following parameters should be considered when developing a bonding procedure specification:

1 General 1.1 Introduction 1.1.1 Purpose The purpose of this standard is to provide procedures and relevant design parameters of limit state design of cargo containment systems of a novel configuration in accordance with Sec.24 [3]. 1.1.2 Limit state design Limit state design is a systematic approach where each structural element is evaluated with respect to possible failure modes related to the design conditions identified in Sec.4 [2.1.4]. A limit state can be defined as a condition beyond which the structure, or part of a structure, no longer satisfies the requirements. 1.1.3 Limit states The limit states are divided into the three following categories:

.1

Ultimate limit states (ULS), which correspond to the maximum load-carrying capacity or, in some cases, to the maximum applicable strain, deformation or instability in structure resulting from buckling and plastic collapse - under intact (undamaged) conditions.

.2 .3

Fatigue limit states (FLS), which correspond to degradation due to the effect of cyclic loading, and: Accident limit states (ALS), which concern the ability of the structure to resist accident situations.

1.1.4 Compliance Sec.4 and Sec.20 through Sec.24 [2] shall be complied with as applicable depending on the cargo containment system concept.

2 Design format 2.1 Design procedure 2.1.1 Design formulation The design format in this standard is based on a load and resistance factor design format. The fundamental principle of the load and resistance factor design format shall verify that design load effects Ld, do not exceed design resistances, Rd, for any of the considered failure modes in any scenario:

A design load Fdk is obtained by multiplying the characteristic load by a load factor relevant for the given load category:

where

γf is load factor, and

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 277

Part 5 Chapter 7 Appendix B

APPENDIX B STANDARD FOR THE USE OF LIMIT STATE METHODOLOGIES IN THE DESIGN OF CARGO CONTAINMENT SYSTEMS OF NOVEL CONFIGURATION

A design load effect Ld (e.g., stresses, strains, displacements and vibrations) is the most unfavourable combined load effect derived from the design loads, and may be expressed by:

where q denotes the functional relationship between load and load effect determined by structural analyses. The design resistance Rd is determined as follows:

where:

Rk

= is the characteristic resistance. In case of materials covered by chapter 6 of this code, it may be, but not limited to, specified minimum yield stress, specified minimum tensile strength, plastic resistance of cross sections, and ultimate buckling strength

γR

= is the resistance factor, defined as

γm

= is the partial resistance factor to take account of the probabilistic distribution of the material properties (material factor)

γs

= is the partial resistance factor to take account of the uncertainties on the capacity of the structure, such as the quality of the construction, method considered for determination of the capacity including accuracy of analysis, and

γC

= is the consequence class factor, which accounts for the potential results of failure with regard to release of cargo and possible human injury.

2.1.2 Consequence classes Cargo containment design shall take into account potential failure consequences. Consequence classes are defined in Table 1, to specify the consequences of failure when the mode of failure is related to the ultimate limit state, the fatigue limit state, or the accident limit state. Table 1 Consequence classes Consequence class

Definition

low

failure implies minor release of the cargo

medium

failure implies release of the cargo and potential for human injury

high

failure implies significant release of the cargo and high potential for human injury/fatality.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 278

Part 5 Chapter 7 Appendix B

Fk is the characteristic load as specified in Sec.4 [3] and Sec.4 [4].

3.1 General 3.1.1 Analysis requirements Three dimensional finite element analyses shall be carried out as an integrated model of the tank and the ship hull, including supports and keying system as applicable. All the failure modes shall be identified to avoid unexpected failures. Hydrodynamic analyses shall be carried out to determine the particular ship accelerations and motions in irregular waves and the response of the ship and its cargo containment systems to these forces and motions. 3.1.2 Buckling strength Buckling strength analyses of cargo tanks subject to external pressure and other loads causing compressive stresses shall be carried out in accordance with Pt.3 Ch.8 or equivalent, e.g. Appendix 4 in CN Spherical. The method shall adequately account for the difference in theoretical and actual buckling stress as a result of plate out of flatness, plate edge misalignment, straightness, ovality and deviation from true circular form over a specified arc or chord length, as relevant. 3.1.3 Fatigue analysis Fatigue and crack propagation analysis shall be carried out in accordance with [5] below.

4 Ultimate limit state 4.1 Design procedure for ULS design 4.1.1 Determination of structural resistance Structural resistance may be established by testing or by complete analysis taking account of both elastic and plastic material properties. Safety margins for ultimate strength shall be introduced by partial factors of safety taking account of the contribution of stochastic nature of loads and resistance considering dynamic loads, pressure loads, gravity loads, material strength, and buckling capacities. 4.1.2 Load combinations and load factors Appropriate combinations of permanent loads, functional loads and environmental loads including sloshing loads shall be considered in the analysis. At least two load combinations with partial load factors as given in Table 2 shall be used for the assessment of the ultimate limit states. Table 2 Partial load factors Load combination

Permanent loads

Functional loads

Environmental loads

a

1.1 1.0

1.1 1.0

0.7 1.3

b

The load factors for permanent and functional loads in load combination a are relevant for the normally wellcontrolled and/or specified loads applicable to cargo containment systems such as vapour pressure, cargo weight, system self-weight, etc. Higher load factors may be relevant for permanent and functional loads where the inherent variability and/or uncertainties in the prediction models are higher.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 279

Part 5 Chapter 7 Appendix B

3 Required analyses

4.1.4 Consequence factors In cases where structural failure of the cargo containment system are considered to imply high potential for human injury and significant release of cargo, the consequence class factor shall be taken as γC = 1.2. This value may be reduced if it is justified through risk analysis and subject to the approval by the Society. The risk analysis shall take account of factors including, but not limited to, provision of full or partial secondary barrier to protect hull structure from the leakage and less hazards associated with intended cargo. Conversely, higher values may be fixed by the Society, for example, for ships carrying more hazardous or higher pressure cargo. The consequence class factor shall in any case not be less than 1.0. 4.1.5 Safety level equivalence The load factors and the resistance factors used shall be such that the level of safety is equivalent to that of the cargo containment systems as described in Sec.20 through Sec.24 [2]. This may be carried out by calibrating the factors against known successful designs. 4.1.6 Material factors

The material factor γm shall in general reflect the statistical distribution of the mechanical properties of the material, and needs to be interpreted in combination with the specified characteristic mechanical properties. For the materials defined in Sec.6, the material factor γm may be taken as: 1) 2)

when the characteristic mechanical properties specified by the Society typically represents the lower 2.5% quantile in the statistical distribution of the mechanical properties, or when the characteristic mechanical properties specified by the Society represents a sufficiently small quantile such that the probability of lower mechanical properties than specified is extremely low and can be neglected.

4.1.7 Resistance factors

The partial resistance factors γsi shall in general be established based on the uncertainties in the capacity of the structure considering construction tolerances, quality of construction, the accuracy of the analysis method applied, etc. 4.1.8 Resistance factors for plastic deformation For design against excessive plastic deformation using the limit state criteria given in [4.1.9], the partial resistance factors γsi shall be taken as follows:

Factors A, B, C and D are defined in Sec.20 Table 2 and Sec.21 Table 1. Rm and ReH are defined in Sec.1. The partial resistance factors given above are the results of calibration to conventional type B independent tanks.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 280

Part 5 Chapter 7 Appendix B

4.1.3 Load factors for sloshing For sloshing loads, depending on the reliability of the estimation method, a larger load factor may be required by the Society.

Stress acceptance criteria given below refer to elastic stress analyses.

.2

Parts with predominating membrane response Parts of cargo containment systems where loads are primarily carried by membrane response in the structure shall satisfy the following limit state criteria:

where: 2

σm σL σb

= equivalent von Mises primary general membrane stress in N/mm

σg

= equivalent von Mises secondary stress in N/mm

= equivalent von Mises primary local membrane stress in N/mm = equivalent von Mises primary bending stress in N/mm

2

2

2

With regard to the stresses σm, σL, σb and σg, see also the definition of stress categories in Sec.4 [6.1.3]. Guidance note: The stress summation described above should be carried out by summing up each stress component (σx, σy, τxy), and subsequently the equivalent stress should be calculated based on the resulting stress components as shown in the example below.

---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

.3

Parts with predominating bending response Parts of cargo containment systems where loads are primarily carried by bending of girders, stiffeners and plates, shall satisfy the following limit state criteria: σms + σbp ≤ 1.25F (See note 1, 2)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 281

Part 5 Chapter 7 Appendix B

4.1.9 Design against excessive plastic deformation Stress response reference .1

σms + σbp + σbs + σbt + σg ≤ 3F Guidance note: The sum of equivalent section membrane stress and equivalent membrane stress in primary structure (σms + σbp) will normally be directly available from three-dimensional finite element analyses. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: The coefficient, 1.25, may be modified by the Society considering the design concept, configuration of the structure, and the methodology used for calculation of stresses. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

where: 2

σms σbp

= equivalent von Mises section membrane stress in primary structure in N/mm

σbs

= equivalent von Mises section bending stress in secondary structure (stiffener) and stress in 2 tertiary structure (plating) caused by bending of secondary structure (stiffener) in N/mm

σbt

= equivalent von Mises section bending stress in tertiary structure, i.e. plate bending stress 2 in N/mm

σg

= equivalent von Mises secondary stress in N/mm

= equivalent von Mises membrane stress in primary structure and stress in secondary (stiffener) and tertiary (plating) structure caused by bending of primary structure

2

Guidance note: The stress summation described above should be carried out by summing up each stress component (σx, σy, τxy), and subsequently the equivalent stress shall be calculated based on the resulting stress components. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

The stresses

σms, σbp, σbs, and σbt are defined in [4.1.9].4. For a definition of σg, see Sec.4 [6.1.3].

Skin plates shall be designed in accordance with the requirements of the administration or recognized organization acting on its behalf. When membrane stress is significant, the effect of the membrane stress on the plate bending capacity shall be appropriately considered in addition.

.4

Section stress categories Normal stress is the component of stress normal to the plane of reference. Equivalent section membrane stress is the component of the normal stress that is uniformly distributed and equal to the average value of the stress across the cross section of the structure under consideration. If this is a simple shell section, the section membrane stress is identical to the membrane stress defined in paragraph [4.1.9].2. Section bending stress is the component of the normal stress that is linearly distributed over a structural section exposed to bending action, as illustrated in Figure 1.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 282

Part 5 Chapter 7 Appendix B

σms + σbp + σbs ≤ 1.25F (See note 2)

4.1.10 Resistance factors for buckling

The same factors γC, γm, γsi shall be used for design against buckling unless otherwise stated in the applied recognised buckling standard. In any case the overall level of safety shall not be less than given by these factors.

5 Fatigue limit states 5.1 Design procedure for FLS design 5.1.1 Fatigue design condition as described in Sec.4 [4.3.3] shall be complied with as applicable depending on the cargo containment system concept. Fatigue analysis is required for the cargo containment system designed under Sec.24 [3]. 5.1.2 The load factors for FLS shall be taken as 1.0 for all load categories. 5.1.3 Consequence class factor γC and resistance factor γR shall be taken as 1.0. 5.1.4 Fatigue damage shall be calculated as described in Sec.4 [4.3.3].2-9 The calculated cumulative fatigue damage ratio for the cargo containment systems shall be less than or equal to the values given in Table 3. Table 3 Maximum allowable cumulative fatigue damage ratio Consequence class Cw 1)

low

medium

1.0

0.5

high 0.5

1)

Lower value shall be used in accordance with Sec.4 [4.3.3].7 to Sec.4 [4.3.3].9. depending on the detectability of defect or crack, etc.

5.1.5 Lower values may be fixed by the Society, for example for tank structures where effective detection of defect or crack cannot be assured, and for ships carrying more hazardous cargo.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 283

Part 5 Chapter 7 Appendix B

Figure 1 Definition of the three categories of section stress (Stresses σbp and σbs are normal to the cross section showed)

6 Accident limit states 6.1 Design procedure for ALS 6.1.1 Accident design condition as described in Sec.4 [4.3.4] shall be complied with as applicable, depending on the cargo containment system concept. 6.1.2 Load and resistance factors may be relaxed compared to the ultimate limit state considering that damages and deformations can be accepted as long as this does not escalate the accident scenario. 6.1.3 The load factors for ALS shall be taken as 1.0 for permanent loads, functional loads and environmental loads. 6.1.4 Loads mentioned in Sec.4 [3.3.9] (static heel loads) and Sec.4 [3.5] (collision and loads due to flooding on ship) of this code need not be combined with each other or with environmental loads, as defined in Sec.4 [3.4]. 6.1.5 Resistance factor γR shall in general be taken as 1.0. 6.1.6 Consequence class factors γC shall in general be taken as defined in [4.1.4], but may be relaxed considering the nature of the accident scenario. 6.1.7 The characteristic resistance Rk shall in general be taken as for the ultimate limit state, but may be relaxed considering the nature of the accident scenario. 6.1.8 Additional relevant accident scenarios shall be determined based on a risk analysis.

7 Testing 7.1 Testing requirements 7.1.1 Cargo containment systems designed according to this standard shall be tested to the same extent as described in Sec.4 [5.2.3], as applicable depending on the cargo containment system concept.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 284

Part 5 Chapter 7 Appendix B

5.1.6 Crack propagation analyses are required in accordance with Sec.4 [4.3.3].6 to Sec.4 [4.3.3].9. The analysis shall be carried out in accordance with methods laid down in a standard recognized by the Society.

July 2017 edition

Changes July 2017, entering into force 1 January 2018. Topic

Reference

Description

Update of gas carrier rules

All.

-

Register information.

Sec.1 [1.4.3]

Guidance note corrected: 0.05MPa instead of old 0.5MPa.

Certification of valves.

Sec.1 Table 7

Addition of following text for valves subject to manufacturer certification: "...or used for isolation of instrumentation lines in piping not greater than 25mm regardless of working temperature.".

Certification requirement Sec.1 Table 7 for hoses.

Certification requirement updated to be relevant only for fixed hoses permanently installed onboard.

Certification requirements for cargo bellows.

Sec.1 Table 7

Certification requirement to bellows added.

Unprotected openings.

Sec.2 [7.1.2]

IACS GC 17 added related to flooding condition.

Wheelhouse windows.

Sec.3 [2.1.5]

Added guidance note on wheel house windows not need to be A0 based on MSC97 modification of the IGC Code in IMO Res. MSC.411 (97).

Closing devices.

Sec.3 [2.1.6]

Modified guidance note to be align with MSC.1/Circ.1599.

Preventing explosion.

Sec.3 [3.1.1]

Guidance note related to MSC.1/Circ.1599 added on applicable SOLAS requirements.

Access.

Sec.3 [5.1.3]

Reference on guidance note to MSC.1/Circ.1599 added.

Pump vents in engine room.

Sec.3 [7.1.5]

Reference on guidance note to MSC.1/Circ.1599 added.

Piping.

Sec.5 [1.1.1]

Reinserted reference to Pt.4 as given in DNV Rules.

Emergency shut down (ESD) valves.

Sec.5 [11.5.3]

Guidance note modified after OCIMF proposal to MSC97 was accepted.

Pressure vessel safety factors (nominal design stress).

Sec.5 [13.6.2]

Same design stress factors on type C tanks and cargo process pressure vessels.

ESD valves.

Sec.8 [2.2.6]

Added guidance note from MSC.1/Circ.1559 on safe means of emergency isolation of pressure relief valves.

Pressure relief valve calculations.

Sec.8 [4.1.1]

Added guidance note from MSC.1/Circ.1559 on definition on L on prismatic tanks.

Nitrogen production.

Sec.9 [2.1.5]

Added text "engine room" to clarify the rules with regard to current practice.

Water spray.

Sec.11 [3.1.7]

Deleted text "Also forward flushing through the nozzles is recommended" and inserted guidance note based on MSC.1/Circ.1599.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 285

Part 5 Chapter 7 Changes – historic

CHANGES – HISTORIC

Reference

Description

Water spray.

Sec.11 [3.1.7]

Added guidance note from MSC.1/Circ.1559 on back flushing of filters.

Testing of filling alarms.

Sec.13 [3.1.5]

Added guidance note with reference to IACS GC 18.

Oxygen monitoring.

Sec.13 [6.1.4]

Modified requirement for oxygen deficiency monitoring from "cargo tank hold space" to "hold spaces for independent tanks other than type C tanks" based on proposal to MSC97 from CCC2 which was accepted.

List of products reference.

Sec.13 [6.1.4]

The words "where indicated in column f in the table of Sec.19 are replaced with the words "where indicated by an "A" in column f in Sec.19 Table 2.

Gas combustion unit (GCU)

Sec.13 Table 1

Modified "Fire detection in GCU Space" to "Fire detection in GCU compartment" to void confusion with GCU fire space.

Reliquefaction plants.

Sec.13 Table 2

All general reliquefaction systems are now covered, regardless of product. Removed comment text on cargo tanks overfill danger.

Liquid in compressor.

Sec.13 Table 2

Added function mist separator to ensure that compressor does get contact with liquid.

Reliquefaction plants.

Sec.13 Table 3

New table covering Brayton LNG cycle add on requirements, in addition to the requirements given in Sec.13 Table 2 relevant for all units. Like the old Table 2 in the previous rule sets.

Shut down matrix.

Sec.13 [15]

Updated references due to new reliquefaction systems given in Sec.13.

January 2017 edition

Main changes January 2017, entering into force July 2017 • Sec.20 Design with independent prismatic tanks of type-A and type-B — Editorial changes have been implemented.

• Sec.23 Design with membrane tanks — Editorial changes have been implemented. — Sec.23 [2.2.2] and Sec.23 [2.2.3]: Changes have been made to formula for σhg due to the change in Pt.3 Ch.4 Sec.2 Table 6, factor for horizontal bending moment from 0.9 to 1.0.

July 2016 edition

Main changes July 2016, entering into force 1 January 2017 • General

These rules are in general updated to be in line with the latest IACS unified interpretations (UI) and unified requirements (UR) following the revised 2016 IGC code.

• Sec.1 General requirements

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 286

Part 5 Chapter 7 Changes – historic

Topic

— Inert gas system has been extended to cover both inert gas generator and nitrogen generator system as separate documentation requirements. — Cargo handling arrangement: Commissioning procedure has been corrected and more detail descriptions for gas trials before and after delivery are added. Documentation requirement for product list has been added. — Vapour handling system (boil-off handling): Additional description has been added. — Reliquefaction system: Document requirements have been added. — Documentation requirement for items with certification requirements (gas combustion unit, cargo pumps, cargo valves and cargo hoses), but currently no documentation requirements, has been added. — Sec.1 Table 7: — — — —

Valves: Corrected to require PC by Society also for valves below -55°C. PC by manufacturer added for reliquefaction unit. Requirement on certification of reliquefaction systems with rule references has been added. Emergency shut down system listed as separate system.

— Sec.1 [6.1.4]: Guidance note has been updated.

• Sec.3 Ship arrangements — Sec.3 [2.1.6]: Guidance note to be in line with IACS GC15 related to closing devices has been added. — Sec.3 [5.1.3]: Guidance note to be in line with IACS GC16 related to minimum openings has been added. — Sec.3 [7.1.5: Guidance note amended to be in line with IACS UI GC12.

• Sec.4 Cargo containment — Sec.4 [2.4.2].4: Guidance note has been added to be in clear line with IACS GC 12 Rev.2. — Sec.4 [5.1.3].5: Guidance note for organic foams has been added.

• Sec.5 Process pressure vessels and liquids, vapour and pressure piping system — Sec.5 [9.3.1].1: Paragraph corrected by replacing or with and. — Sec.5 [13.1.2]: Paragraph updated in line with IACS G3 Rev.3.

• Sec.7 Cargo pressure - temperature control — Sec.7 [2.1.2]: Guidance note: Table heading amended and sentence included below table for further clarification.

• Sec.9 Cargo containment system atmospheric control — Sec.9 [2.1.1]: Guidance note added.

• Sec.12 Artificial ventilation in cargo area — Sec.12 [2.1.2]: Text in guidance note has been modified with case by case acceptance.

• Sec.13 Instrumentation and automation — Sec.13 [1.1.4]: Listing of all systems removed. — Sec.13 [15]: Guidance on alarm and shut down added.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 287

Part 5 Chapter 7 Changes – historic

— Sec.1 Table 1: Barge for liquefied gas and Barge for c added to ship type notations. — Sec.1 Table 6:

Part 5 Chapter 7 Changes – historic

• Sec.18 Cargo operation manual and cargo emergency shutdown system — Sec.18 [2.2.3]: Guidance note related to closing time of ESD valves has been added.

• Sec.20 Design with independent prismatic tanks of type-A and type-B — Sec.20 [3.1.1]: Better wording.

• Sec.23 Design with membrane tanks — Sec.23 [2.2.1]: Repeating sentence is removed.

January 2016 edition This document supersedes the October 2015 edition.

Main changes January 2016, entering into force as from date of publication • Sec.9 Cargo containment system atmospheric control — Implement UR F20 Rev.7

• Sec.20 Design with independent prismatic tanks of type-A and type-B — [1.6.3]: Permissible stress coefficient has been updated in accordance with Pt.3 Ch.6 Sec.5. — [3.2.8]: The acceptance criterion has been changed from AC-III to AC-I for calculation of longitudinal bulkhead of independent tank. — Table 4: Allowable stresses for AC-III have been changed for fine mesh analysis.

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.7. Edition January 2018 Liquefied gas tankers

DNV GL AS

Page 288

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition October 2015 Amended July 2016

Part 5 Ship types Chapter 8 Compressed natural gas tankers

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS October 2015

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

Part 5 Chapter 8 Changes - current

CHANGES – CURRENT This was a new edition in October 2015 and has been amended latest in July 2016. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Amendments July 2016 • General — Only editorial corrections have been made.

Amendments January 2016 • General — Only editorial corrections have been made.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 3

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................... 7 1 Introduction.........................................................................................7 1.1 Introduction..................................................................................... 7 1.2 Scope..............................................................................................7 1.3 Application....................................................................................... 7 1.4 Fundamental safety requirements....................................................... 7 2 Class notations.................................................................................... 9 2.1 Ship type notations.......................................................................... 9 3 Definitions........................................................................................... 9 3.1 Terms..............................................................................................9 4 Documentation...................................................................................10 4.1 Documentation requirements............................................................10 Section 2 Materials................................................................................................16 1 General.............................................................................................. 16 1.1 Materials........................................................................................ 16 1.2 Design temperature........................................................................ 16 Section 3 Ship arrangement and location of cargo tanks...................................... 18 1 General.............................................................................................. 18 1.1 General..........................................................................................18 1.2 Divisions........................................................................................ 18 1.3 Collision and grounding................................................................... 18 Section 4 Arrangements and environmental control in hold spaces...................... 20 1 General.............................................................................................. 20 1.1 General..........................................................................................20 1.2 Inerting of hold spaces....................................................................20 1.3 Overpressure protection of hold spaces............................................. 20 1.4 Drainage........................................................................................ 21 1.5 Area classification........................................................................... 21 Section 5 Scantling and testing of cargo tanks..................................................... 22 1 General.............................................................................................. 22 1.1 General..........................................................................................22 2 Coiled type cargo tank.......................................................................22

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 4

Part 5 Chapter 8 Contents

CONTENTS

3 Cylinder type cargo tank................................................................... 23 3.1 Cargo tank cylinder.........................................................................23 3.2 Cargo tank piping........................................................................... 26 3.3 Welding requirements......................................................................26 3.4 Pressure testing and tolerances........................................................ 27 3.5 Non-destructive testing (NDT).......................................................... 27 3.6 Post weld heat treatment.................................................................27 3.7 Prototype testing............................................................................ 27 4 Composite type cargo tank................................................................ 27 4.1 General..........................................................................................27 4.2 Cargo tank cylinder - calculations..................................................... 28 4.3 Cargo tank piping........................................................................... 30 4.4 Production requirements and testing after installation..........................30 4.5 Full scale prototype pressure testing and tolerances............................ 30 4.6 Non-destructive testing (NDT).......................................................... 33 4.7 Composite - metal connector interface.............................................. 33 4.8 Inner liner..................................................................................... 33 4.9 Outer liner..................................................................................... 35 4.10 Installation................................................................................... 36 Section 6 Piping systems in cargo area................................................................ 37 1 General.............................................................................................. 37 1.1 Bilge, ballast fuel oil piping.............................................................. 37 1.2 Cargo piping, general...................................................................... 37 1.3 Cargo valves.................................................................................. 37 1.4 Cargo piping design........................................................................ 37 Section 7 Overpressure protection of cargo tanks and cargo piping system..........39 1 General.............................................................................................. 39 1.1 Cargo piping.................................................................................. 39 1.2 Cargo tanks................................................................................... 39 Section 8 Gas-freeing of cargo containment system and piping system................ 41 1 General.............................................................................................. 41 1.1 General..........................................................................................41 Section 9 Mechanical ventilation in cargo area..................................................... 42 1 General.............................................................................................. 42 1.1 General..........................................................................................42

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 5

Part 5 Chapter 8 Contents

2.1 General..........................................................................................22

Section 10 Fire protection and extinction............................................................. 43 1 General.............................................................................................. 43 1.1 General..........................................................................................43 1.2 Structural fire preventive measures...................................................43 1.3 Means of escape.............................................................................44 1.4 Firefighter’s outfit........................................................................... 44 1.5 Fire main....................................................................................... 44 1.6 Dual agent (water and powder) for process and load/unload area.......... 45 1.7 Water spray................................................................................... 45 1.8 Spark arrestors...............................................................................46 Section 11 Electrical installations......................................................................... 47 1 General.............................................................................................. 47 1.1 General..........................................................................................47 Section 12 Control and monitoring....................................................................... 48 1 General.............................................................................................. 48 1.1 General..........................................................................................48 Section 13 Tests after installation........................................................................ 49 1 General.............................................................................................. 49 1.1 General..........................................................................................49 Section 14 Filling limits for cargo tanks............................................................... 50 1 General.............................................................................................. 50 1.1 General..........................................................................................50 Section 15 Gas specification................................................................................. 51 1 General.............................................................................................. 51 1.1 General..........................................................................................51 Section 16 In service inspection plan................................................................... 52 1 General.............................................................................................. 52 1.1 General..........................................................................................52 Changes – historic................................................................................................ 53

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 6

Part 5 Chapter 8 Contents

1.2 Ventilation in hold spaces................................................................ 42

Symbols For symbols and definitions not given in this chapter, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction The rules in this chapter apply to ships engaged in the transportation of compressed natural gases (CNG). For liquefied gas carriers reference is made to Ch.7. Guidance note: The vessel is to be accepted by the flag state and the respective port authorities ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Scope The rules in this chapter gives requirements to cargo tank strength and materials, systems and equipment, safety and availability, and the relevant procedural requirements applicable to ships engaged in the transportation of compressed natural gases.

1.3 Application 1.3.1 The requirements in this chapter shall be regarded as supplementary to those given for the assignment of main class Pt.2, Pt.3 and Pt.4. 1.3.2 The minimum and/or maximum operating temperature (°C), maximum acceptable cargo density (kg/ 3 m ) and the design pressure (MPa), will be stated in the Society’s “Register of Vessels”. In the case of carriage of the gas in the chilled condition the carriage temperature will be stated. If no chilling is provided ambient temperature will be stated. 1.3.3 Ships having offshore loading arrangements shall comply with the requirements in Pt.6 Ch.4 Sec.1. 1.3.4 The process plant, relief and flare system shall be designed according to a standard recognised by the Society.

1.4 Fundamental safety requirements 1.4.1 The overall safety with respect to life, property and environment shall be equivalent to or higher than comparable LNG vessels built and operated according to typical ship rules and industry practices. 1.4.2 For new concepts a quantitative risk assessment (QRA) shall be submitted as a part of the classification documentation. The QRA shall comply with the principles for safety assessment outlined in e.g. IMO Report MSC 72/16. For new concepts or modifications to existing systems a hazard identification (HAZID)/hazard operability study (HAZOP) of the cargo tank, cargo piping, process system, operational procedures etc. shall be submitted for information.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 7

Part 5 Chapter 8 Section 1

SECTION 1 GENERAL

— life, with respect to crew and third party personnel — property, e.g. damage to ship and off-hire — environment, e.g. gas release to the atmosphere. 1.4.4 The safety level of a LNG carrier represents the minimum acceptable safety level for a CNG vessel. The targets shall therefore be based on historical experience as shown in Table 1. Table 1 Safety target values for CNG carriers (annual risk) 1)

Historical data LNG Individual risk for crew members due to major accidents

1.2 · 10

Total loss due to collision

1.2 · 10

Total loss due to cargo hazards, e.g. fires and explosions

2.4 · 10

Target safety values for CNG

-4

1 · 10

-4

-4

1 · 10

-4

-4

1 · 10

-4

Individual risk from cargo cylinder failure

1 · 10

-5

Individual risks for public ashore

1 · 10

-5

1)

Comment Does not include occupational risks and work place accidents Total loss frequency – generic LNG vessel Total loss frequency – generic LNG vessel Safety class high, as defined in the Society's document DNVGL ST F101 See IMO MSC 72/16 Annex 1

The historical data for LNG vessels has been taken from the Society's Technical Report No. 2001-0858.

In addition, the as low as reasonably practicable (ALARP) principle shall be adopted as a safety philosophy to ensure: — focused and continuous safety efforts — that the overall (and absolute) targets are not misused to argue that sound safety measures are not implemented. Guidance note: ALARP is applied on a project specific basis and applies the principles that: —

Intolerable risk cannot be justified and the vessel cannot be built or continue to operate.

—

Where the risk is below this level but higher than the broadly acceptable risk, then the risk is tolerable provided that the risk is ALARP, i.e. further risk reduction is impracticable or its cost is grossly disproportional to the risk improvement gained. This means that the owner or operator shall take all reasonably practicable precautions to

—

reduce the risk, either by ensuring the faults do not occur, or that if they do then their consequences are not serious.

—

In the broadly acceptable region, the risk is so low that further risk assessment or consideration of additional precautions is unnecessary. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 8

Part 5 Chapter 8 Section 1

1.4.3 The fundamental safety requirements shall take into consideration safety targets for:

2.1 Ship type notations 2.1.1 Vessels built in compliance with the requirements as specified in Table 2 will be assigned the mandatory class notation as follows: Table 2 Ship type notations

Class notation

Description

Qualifier

Tanker for compressed natural gas

Ship intended for carriage of compressed natural gas

<none>

Additional description

Design requirements, rule reference

Pt.5 Ch.8

3 Definitions 3.1 Terms Table 3 Definitions Terms

Definition

blow down

depressurising or disposal of an inventory of pressurised gas

cargo area

that part of the ship which contains the cargo tanks, hold spaces, process area, turret space and cofferdams and includes deck areas over the full length and breadth of the part of the ship over the above-mentioned spaces

cargo hold vent pipes

low pressure pipes for venting of cargo hold spaces to vent mast

cargo load/unload valve

the valve isolating the cargo piping from external piping

cargo piping

the piping between the cargo tank valve and the cargo load and or unload valve

cargo tank

consists of the storage system for the compressed gas, i.e. all pressurised equipment up to the cargo tank valve

cargo tank valve

isolates the cargo tank from the cargo piping

cargo vent piping

the piping from the cargo relief valve to the vent mast

class H fire division

divisions formed by bulkheads and decks. See Sec.10 [1.2.8]

coiled type cargo tank

a cargo tank consisting of long lengths of small diameter coiled piping

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 9

Part 5 Chapter 8 Section 1

2 Class notations

Definition

cylinder type cargo tank

a cargo tank consisting of an array of cylinder type pressure vessels connected by cargo tank piping. The following definitions are relevant for the cylinder type tank: — cargo tank cylinder is a large diameter cylinder, i.e. standard offshore pipe, composite wrapped pipe of composite tank, with end-caps constituting the main tank volume — cargo tank piping is the piping connecting the cargo tank cylinders up to the cargo tank valve

pressure

the following pressure definitions are used: — design pressure is the maximum gauge gas pressure which has been used in the calculation of the scantlings of the cargo tank and cargo piping. Design pressure defined in these rules is synonymous with “incidental pressure” as used in the Society's document DNVGL ST F101 — maximum allowable operating pressure is 95% of the design pressure — set pressure of pressure relief system, the design pressure less the tolerance of the pressure relief system

design temperature

design temperature for the selection of materials in cargo tanks, piping, supporting structure and inner hull structure is the lowest or highest temperature which can occur in the respective components. Reference is made to Sec.2 [1.2]

gas dangerous area and zones

regarding the definitions of gas dangerous area and zones the principles of Ch.7 Sec.1 and Ch.7 Sec.10 applies. The extension of the gas dangerous zones shall be re-evaluated taking into account high pressure relief sources and new equipment. IEC-92 may be used for guidance in evaluating the extent of the zones

hold space

the space enclosed by the ship's structure in which a cargo tank is situated

hold space cover

the enclosure of hold space above main deck ensuring controlled environmental conditions within the hold space

4 Documentation 4.1 Documentation requirements 4.1.1 General For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 4.1.2 Other plans, specifications or information may be required depending on the arrangement and the equipment used in each separate case.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 10

Part 5 Chapter 8 Section 1

Terms

Table 4 Documentation requirements Object

Documentation type

Additional description

Bilge water control Z030 – Arrangement plan and monitoring system Hazardous area classification

Explosion (Ex) protection

Sensors in hold spaces.

G080 – Hazardous area classification drawing

Info AP AP

E170 – Electrical schematic drawing

Single line diagrams for all intrinsically safe circuits, for each circuit including data for verification of the compatibility between the barrier and the field components.

AP

Z030 – Arrangement plan

Electrical equipment in hazardous areas. Where relevant, based on an approved ‘hazardous area classification drawing’ where location of electric equipment in hazardous area is added (except battery room, paint stores and gas bottle store).

AP

Z250 – Explosion protected equipment maintenance plan

AP

I200 – Control and monitoring system documentation

AP — Including drying and backflow prevention arrangements.

S010 – Piping diagram (PD)

— Inerting, purging and gas freeing of cargo tanks and hold spaces.

AP

To show all details including

Inert gas system

— inert gas plant — cooling and cleaning devices

Z030 – Arrangement plan

— non-return devices

AP

— pressure vacuum devices — inert gas distribution piping. Z161 – Operational manual

Emergency shut down (ESD) system

Hydrocarbon gas detection and alarm system, fixed

Fire water system

FI

G130 – Cause and effect diagram

Including all items that gives alarm and automatic shutdown.

AP

I200 – Control and monitoring system documentation

AP

I200 – Control and monitoring system documentation

AP

Z030 – Arrangement plan

Detectors, call points and alarm devices.

AP

S010 – Piping diagram (PD)

AP

S030 – Capacity analysis

AP

Z030 – Arrangement plan

AP

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 11

Part 5 Chapter 8 Section 1

4.1.3 Documentation shall be submitted as required by Table 4.

Documentation type

Additional description

Cargo tank deck fire extinguishing system

G200 – Fixed fire extinguishing system documentation

AP

Cargo handling spaces fire extinguishing system

G200 – Fixed fire extinguishing system documentation

AP

External surface protection water-spray system

G200 – Fixed fire extinguishing system documentation

AP

Ventilation systems for Z030 – Arrangement plan cargo handling spaces Z100 – Specification

Info

Including gas safe spaces and air locks in cargo area.

AP

Fans.

FI

— For new concepts a quantitative risk assessment (QRA) shall be submitted as a part of the classification documentation. The QRA shall comply with the principles for formal safety assessment outlined in IMO Report MSC 72/16 and 74/19. — For new concepts or modifications to existing systems a hazard identification (HAZID)/ hazard and operability study (HAZOP) of the cargo system, process system (if applicable), operational procedures etc.

G010 – Risk analysis

FI

— For new concepts documentation of fire loads based on risk analysis and fire and explosion analysis. In case of cold venting. Purpose to evaluate the extent of the gas dangerous area.

G110 – Dispersion study

Cargo handling arrangements

FI

G120 – Escape route drawing

FI

G170 – Safety philosophy

FI

P050 – Flare heat radiation study

Heat radiation towards cargo holds and other important areas and equipment.

FI

P080 – Flare and blow down system report

Blow down calculations also including cooling effect of depressurizing.

FI

Locations of — machinery spaces, accommodation, service and control station spaces, chain lockers, cofferdams, fuel oil tanks, drinking and domestic water tanks and stores Z030 – Arrangement plan

— cargo tanks and cargo piping systems — cargo control rooms

AP

— cargo piping with shore or offshore connections including loading and discharge arrangements and emergency cargo dumping arrangement, if fitted — ventilation system with capacity.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 12

Part 5 Chapter 8 Section 1

Object

Documentation type

Additional description

Z100 – Specification

Insulation including arrangement, if fitted.

FI

Z161 – Operational manual

Information related to all cargo operations.

AP

Z330 – Cargo list

Information on gas specification to be carried on the ship.

FI

Z254 – Commissioning procedure

Gas trial program for complete cargo system including tanks.

AP

— Cargo and process piping including vapour piping and vent lines of safety relief valves or similar piping, and relief valves discharging cargo from the cargo piping system.

S010 – Piping diagram (PD)

AP

— Auxiliary systems like glycol, steam, lubrication oil, etc., if fitted.

Cargo piping system

Cargo valves control and monitoring systems

Info

S070 – Pipe stress analysis

Complete stress analysis for each branch of the cargo piping system according to ANSI/ASME B31.3.

FI

S90 – Specification of pipes, valve, flanges and fittings

Including non-destructive testing specification.

AP

I200 – Control and monitoring system documentation

AP — Stress analysis including interaction between hull and tank system. — Ultimate (burst) strength of the cargo tanks. — Fatigue analysis for cargo tanks.

C040 – Design analyses

— Relevant fatigue crack propagation calculations for cargo tanks.

FI

— Fatigue crack propagation calculations for the cargo tank piping using leak-before-failure principle. Compressed gas cargo tank arrangements

H131 – Non-destructive testing (NDT) plan

Welds.

AP

M010 – Material specification, metals

Including internal structures and piping.

AP

M030 – Material specification, non-metallic material

AP

M060 – Welding procedures (WPS)

AP

P030 – Temperature calculation

Calculation of maximum and minimum design temperature for materials in the cargo tank, supporting structure and inner hull due to loading/ unloading and depressurising.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

FI

Page 13

Part 5 Chapter 8 Section 1

Object

Documentation type

Additional description

Info

All tank details including — complete tank — access for inspection — support arrangement with anti-float/anti-roll supports

Z030 – Arrangement plan

AP

— tank and hold space insulation, if fitted — tank connections — hold space — temperature keeping arrangement, if fitted. Z030 – Arrangement plan

Protection of cargo tank system with double hull and minimum distance to ship bottom.

AP

Z252 – Test procedure at manufacturer

Prototype testing with full scale fatigue and burst tests for cargo tanks.

AP

Z051 – Design basis

The cooling effect from gas released as a result of a leakage or rupture of piping and cargo tank.

AP

— Raking damage calculations, showing that the maximum ship speed, at which the extent of raking damage will not penetrate into the forward cargo hold space, is sufficient for safe manoeuvring of the ship at not less than 5 knots.

Z265 – Calculation report

FI

— Collision damage analysis which demonstrates that the energy absorption capability of the ship side is sufficient to prevent the bow of the striking vessel(s) to damage the cargo tanks. — Hull steel temperature when cargo temperature is below -10°C.

Z265 – Calculation report

FI

— Vibration analysis if considered relevant. Cargo compartments over- and underpressure prevention arrangements

Z100 – Specification

Relief valves.

AP

Z265 – Calculation report

Required cargo hold relief hatch capacity.

FI

— Gas leak monitoring. Cargo compartment control and monitoring systems

I200 – Control and monitoring system

I260 – Plan for periodic test of field instruments

— Temperature in cargo tanks. — Temperature and oxygen in hold spaces.

AP

— Moisture and H2S at load/unload or shore connection. Including intervals between recalibration.

FI

Pressure in Cargo pressure control I200 – Control and monitoring and monitoring system system

— each hold space — each cargo tank

AP

— cargo piping at load/unload connection.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 14

Part 5 Chapter 8 Section 1

Object

Documentation type

Additional description

I260 – Plan for periodic test of field instruments

Including intervals between recalibration

Info FI

4.1.4 Reference documents are: — Ch.7 Liquefied gas carriers — The Society document DNVGL ST F101 Submarine pipeline systems — International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk, IGC Code, Res. MSC. 370(93) — ASME VIII Div.2 - ASME Boiler and Pressure Vessel Code - Alternative Rules for Pressure Vessels — ASME VIII Div.3 - ASME Boiler and Pressure Vessel Code - Alternative Rules for Construction of High Pressure Vessels — ASME B31.3 - Process Piping — API RP521 - Guide for Pressure Relieving and Depressurizing Systems — The Society document DNVGL ST C501 Composite components.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 15

Part 5 Chapter 8 Section 1

Object

1 General 1.1 Materials 1.1.1 The materials used in the hull structure shall comply with the requirements for manufacture, survey and certification given in Pt.2 and Pt.3 Ch.3 Sec.1. 1.1.2 For the cylinder type cargo tank the materials used in the cylinder and end-caps shall comply with the requirements for manufacture, survey and certification given in the Society's document DNVGL ST F101. See also [1.1.7]. Due regard shall be given to corrosion protection. Guidance note: The use of suitable protective coating or liners can be an acceptable means of corrosion protection. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.3 For the coiled type cargo tank the materials used shall comply with the requirements for manufacture, survey and certification given in the Society's document DNVGL ST F101 or a recognised standard accepted by the Society. See also [1.1.7]. 1.1.4 The materials used in the cargo tank piping, cargo piping and all valves and fittings shall be of quality VL 316L or equivalent with respect to ductility, fatigue and corrosion resistance, and shall comply with the requirements for manufacture survey and certification given in Pt.2 and Ch.7. Guidance note: Unprotected piping on open deck is recommended to be painted. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.5 Cargo hold vent pipes shall be of a fire resistant material capable of withstanding the calculated pressure. 1.1.6 Composite materials will be specially considered. Composite material used in cargo tanks shall comply with Sec.5 [4]. 1.1.7 All material used in the cargo tank and cargo piping shall be made at an approved manufacturer and provided with material certificate issued by the Society.

1.2 Design temperature 1.2.1 The maximum design temperature for selection of materials is the highest temperature which can occur in the cargo tanks or cargo piping due to: — loading/transport/unloading. 1.2.2 The minimum design temperature for the selection of materials is the lowest temperature which can occur in the cargo tanks, cargo piping, supporting structure or inner hull due to: — loading/transport/unloading — the cooling effect from accidental release of cargo gas. When determining the minimum design temperature the cooling effects from an accidental release inside the cargo holds shall be documented. The documentation shall address: — a leakage or complete rupture of the cargo tank piping at one location for the cylinder type system

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 16

Part 5 Chapter 8 Section 2

SECTION 2 MATERIALS

Partial protective boundaries shall be provided to prevent direct cooling down of tank units or of ship's structure. Ambient temperatures for calculating the above steel temperatures shall be 5°C for air and 0°C for sea water unless other values are specified for special areas.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 17

Part 5 Chapter 8 Section 2

— the cooling effect from the complete rupture of one pipe in the coil for the coiled system.

1 General 1.1 General 1.1.1 The ship shall meet the requirements to survival capability and ship arrangement as given in Ch.7 Sec.2 and Ch.7 Sec.3. In addition the below requirements applies. 1.1.2 A tanker for compressed natural gas is to be of a double hull construction with double sides and double bottom. Equivalent bottom solutions may be used if they can be shown by calculations or tests to offer the same protection to the cargo tanks against indentations and have the same energy absorption capabilities as conventional double bottom designs, see raking damage described in [1.3.1].

1.2 Divisions The cargo holds shall be segregated from engine rooms and accommodation spaces and similar spaces, by cofferdams, see Ch.7 Sec.3.

1.3 Collision and grounding 1.3.1 For conventional double bottom designs the double bottom height shall at least be B/15 or 3 m whichever is less, but not less than 1.0 m. A safe maximum navigating speed whereby the cargo tank or its supports are not damaged by grounding on a rocky seabed, shall be determined by grounding raking damage calculations. The maximum navigating speed shall be equal to or larger than the minimum safe manoeuvring speed of the vessel. For the purpose of these calculations this speed shall not be taken to be less than 5 knots. Guidance note: For grounding raking damage calculations a triangular shaped rock with a width of twice the penetrating height may be used. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3.2 A collision frequency analysis shall, for new projects, be conducted for a characteristic vessel trade. The analysis shall determine the annual collision frequency and associated collision energies of striking vessels, based on vessel sizes, types and speeds determined from traffic data for the selected trade. If applicable traffic data for the actual trade is not available, or no specific trade rather than world-wide trading is planned, relevant traffic data for North Sea trading acceptable to the Society may be used. 1.3.3 Collision damage analysis shall be conducted to demonstrate that: — For the ship sizes and energies determined in [1.3.2] the energy absorption capability of the ship side shall be sufficient to prevent the bow of the striking vessel(s) from penetrating the double side in to the position of the cargo tanks, thus not damaging the cargo tanks. Alternatively: For the purpose of the calculations it may conservatively be assumed that all the collision energy will be absorbed by the struck ship side. Hence, the following simplifications will be accepted: — the use of an infinitely stiff striking bow — hit perpendicular to the ship side and no rotation of struck ship — no common velocity of the two ships after collision

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 18

Part 5 Chapter 8 Section 3

SECTION 3 SHIP ARRANGEMENT AND LOCATION OF CARGO TANKS

1.3.4 The minimum collision energy in MJ to be absorbed in the collision shall be taken as:

where:

Lpp Δ1

= length between perpendiculars of the CNG vessel in m

ΔCNG

= the displacement of the struck CNG vessel, in tons.

= the displacement of the average size of the population of striking vessels which can be taken as 10000 tons

1.3.5 For conventional double side designs the width of the double side shall at least be minimum B/15 or 2 m whichever is the greater. Equivalent side solutions may be used if they can be shown by tests or calculations to offer the same protection to the cargo tank against indentations, i.e. the same energy absorption capabilities as conventional double side designs, and complies with the energy absorption requirements in [1.3.2], [1.3.3] and [1.3.4] whichever is the more conservative. The minimum horizontal distance from the outer hull to the cargo containment system shall not be less than as stated in the beginning of this paragraph. 1.3.6 Due to changing ship lines at the ends of the cargo area it will be acceptable to apply the minimum double bottom height in [1.3.1] and the minimum double side width in [1.3.5] at the forward cross-section and aft cross-section of the of the cargo area. When the side width, w, and the double bottom height, h, are different, the distance w shall have preference at levels exceeding 1.5 h above the base line as shown in Figure 1.

w

w

w

w

h <w

h>w

h

h h

1.5 h

h base line

Figure 1 Minimum double bottom height and double side width

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 19

Part 5 Chapter 8 Section 3

In lieu of more specific information a raking bow with a stem angle of 65 degrees, i.e. a typical bow for a 5000 tonnes standard supply vessel, may be used. It shall be demonstrated by calculations that the side of the CNG carrier has an energy absorption capability according to [1.3.2], but not less than given by the formula in [1.3.4] without the bow penetrating into the position of the cargo tanks.

1 General 1.1 General 1.1.1 The principles for access for inspection given in Ch.7 Sec.3 [5] shall be used where visual inspection is required. For the cylinder type cargo tank access for inspection of cargo tank cylinders, supports, foundations and cargo tank piping shall be arranged from outside the cylinders. For the coiled type cargo tank a method for inspection from inside by use of special inspection tools shall be predetermined. 1.1.2 An inspection plan shall be developed and submitted for approval. The plan shall include a detailed description on how safe access for inspection is provided. 1.1.3 The cargo tank valve shall be mounted outside the hold space. For enclosed hold spaces the provisions in [1.2] and [1.3] apply. Guidance note: Cargo tanks may be located in enclosed or open hold spaces. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.4 For open hold spaces special attention shall be given to corrosion protection and fire protection of the cargo tanks and the possibility for detecting a leak within the cargo area.

1.2 Inerting of hold spaces 1.2.1 The hold space shall be inerted with nitrogen or inerted with other suitable non-corrosive medium. The nitrogen supply system shall be arranged to prevent back flow in the case of overpressure in the hold space. The nitrogen system shall be designed with redundancy to the extent necessary for maintaining safe operation of the vessel. 1.2.2 For composite cargo tanks the hold space is to be enclosed and inerted. The atmosphere in the hold space is to be purged with nitrogen or other suitable inert gas and the concentration is to be kept under 30% of LEL (lower explosion limit).

1.3 Overpressure protection of hold spaces 1.3.1 Hold spaces shall be fitted with an overpressure protection system. The following functional requirements apply: a) b)

c) d) e)

Pressure control of inerted atmosphere with positive pressure automatically adjusted between 0.005 and 0.015 MPa above atmospheric pressure shall be provided. Pressure relief device, normally set to open at 0.025 MPa, shall be provided. The relief device shall have sufficient capacity to handle a rupture of the largest cargo tank piping in the hold space for the cylinder type cargo tank and a rupture of one pipe in the coil for the coiled type cargo tank. This applies to the largest cargo tank in the relevant hold space. The discharge from the hold spaces shall be routed to a safe location. In addition to the relief system required by b) relief hatches, normally set to open at 0.04 MPa shall be provided in each hold space cover. It shall be demonstrated that the pressure protection devices and their surrounding structures are capable of handling the lowest temperature achieved during pressure relieving at maximum capacity.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 20

Part 5 Chapter 8 Section 4

SECTION 4 ARRANGEMENTS AND ENVIRONMENTAL CONTROL IN HOLD SPACES

1.4.1 Hold spaces shall be provided with a suitable drainage arrangement not connected with machinery spaces. Means for detecting leakage of water into the hold space shall be provided.

1.5 Area classification 1.5.1 The extent of gas dangerous zones and gas dangerous spaces shall follow the principles in Ch.7. 1.5.2 If cold venting is used for the gas relief system a gas dispersion analysis shall be conducted in order to evaluate the extent of the gas dangerous zone. The analyses shall be carried out according to a recognised standard/software and the boundaries of the gas dangerous zone shall be based on 50% LEL (lower explosion limit) concentration.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 21

Part 5 Chapter 8 Section 4

1.4 Drainage

1 General 1.1 General 1.1.1 The cargo tank shall be designed using model tests, refined analytical tools and analysis methods to determine stress levels, fatigue life and crack propagation characteristics. Changes to material properties with time due to long term static loads and the environment shall also be considered for composites. 1.1.2 The cargo tank together with supports and other fixtures shall be designed taking into account all relevant loads listed in Ch.7 Sec.4. 1.1.3 The dynamic loads due to ship motions shall be taken as the most probable largest loads the ship will -8 encounter during its operating life, normally taken to correspond to a probability level of 10 in the North Atlantic environment. Loading rates shall be considered for composites, since these materials have rate dependent properties. 1.1.4 The dynamic effect of pressure variations due to loading and unloading shall represent the extreme service conditions the containment system will be exposed to during the lifetime of the ship. As a minimum the design number of pressure cycles from maximum pressure to minimum pressure shall not be less than 50 per year. 1.1.5 Vibration analysis shall be carried out as outlined in Ch.7 Sec.4. 1.1.6 Transient thermal loads during loading and unloading shall be considered. 1.1.7 The effects of all dynamic and static loads shall be used to determine the strength of the structure with respect to: — — — —

maximum allowable stresses buckling cyclic and static fatigue failure crack propagation.

1.1.8 For cargo tank types other than coiled type and cylinder type, the requirements for cylinder type tanks given in [3] applies, as relevant. 1.1.9 Process prototype testing shall be carried out to document that the system functions as specified with respect to accumulation and disposal of liquids. It shall be verified that liquid hammering does not occur in the piping system during any operation. Where it is impractical to perform full scale testing, successful operation can be simulated computationally and in small scale testing to provide adequate assurance of functionality. Commissioning and start-up testing shall be witnessed by a surveyor and is considered complete when all systems, equipment and instrumentation are operating satisfactorily.

2 Coiled type cargo tank 2.1 General Requirements for the coiled type cargo tank shall be specially considered. The requirements applicable for the cylinder type cargo tank shall be complied with, as found relevant.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 22

Part 5 Chapter 8 Section 5

SECTION 5 SCANTLING AND TESTING OF CARGO TANKS

3.1 Cargo tank cylinder 3.1.1 The stresses in the cargo cylinder and the hemispherical end caps shall fulfil the burst requirements given in DNVGL ST F101 for safety class high. Recognised standards such as the ASME BPV VIII Div. 3 may also be used. The pressure used for calculating the wall thicknesses is the design pressure defined in Sec.1 Table 3. The maximum operating pressure shall not be higher than 95% of the design pressure. Hemispherical ends shall have a cylindrical extension (skirt) so that the distance to the circumferential weld to the cylinder is not less than:

where:

R t

= radius in mm of hemispherical end = thickness in mm of hemispherical end.

For elliptical or toro-spherical end-caps additional requirements may apply subject to agreement with DNV GL. The local equivalent surface stress (primary bending + membrane stress) in the cargo tank cylinders according to von Mises shall not exceed 0.8 ReH. The cargo tank cylinder shall be subject to fatigue analysis by both S-N curves and fracture mechanics crack propagation analysis as described in [3.1.2] and [3.1.3]. The number of load cycles to be used for design is the number of cycles expected during design life multiplied by a design fatigue factor (DFF) in order to achieve an appropriate safety level. The minimum calculated fatigue life for all analysis options is not to be less than 25 × DFF years. 3.1.2 S-N curves shall be applicable for the material, the construction detail and the state of stress in question. Model testing of cargo tank details as fabricated is required to establish the curve. Testing shall be carried out for longitudinal welds and circumferential girth welds of the cargo cylinders. Testing may also be required for special details as deemed necessary by DNV GL. Guidance note: The test specimens can be either coupon tests or full ring test specimens cut from fabricated cylinders at the actual pipe production line. Normally, ring tests will provide more realistic results for longitudinal welds. For circumferential girth welds coupon tests should be carried out. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Two alternative formulations are given based on the following definitions of characteristic value for log10N for the system of ns cylinders: 1) 2)

Mean value minus 3 standard deviations (μ-3σ) and no further adjustment Mean value minus 2 standard deviations (μ-2σ), supplemented with a system effect term.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 23

Part 5 Chapter 8 Section 5

3 Cylinder type cargo tank

Alternative 1: The characteristic S-N curve for use in design is defined as the “mean-minus-three-standard-deviations” curve as obtained from a log10Δσ -log10N plot of experimental data. With a Gaussian assumption for the residuals in log10N with respect to the mean curve through the data, this corresponds to a curve with 99.865% survival probability. The uncertainty in this curve when its derivation is based on a limited number of test data shall be accounted for. It is required that the characteristic curve be estimated with at least 95% confidence. When a total of n observations of the number of cycles to failure N are available from n fatigue tests carried out at the same representative stress range Δσ, then the characteristic value of log10N at this stress level is to be taken as:

where: = mean value of the n observed values of log10N

c3 (n)

= factor whose value depends on number of tests n and is tabulated in Table 1 = standard deviation of the n observed values of log10N.

The combined Miner sum for fatigue loads due to loading/unloading and dynamic ship loads is not to be higher than 0.1 (DFF = 10) for cylinders with design S-N curve established as mean minus 3 standard deviations and with enhanced control in fabrication with respect to production tolerances. Out-of-roundness has not been specifically considered for the longitudinal welds, and the weld length is not explicitly accounted for in the design analyses. The safety level is calibrated for a long weld. Alternative 2: Here the system information is taken into account providing an estimate of the characteristic value of log10N for the system based on “mean value minus two standard deviations” of the test data.

where:

c2 (n)

is a factor whose value depends on number of tests n and is tabulated in Table 1 corresponding to a 97.725% probability of survival. For

logN

= 0.20, the expression for the characteristic value of log10N for the system is identical

to the expression for the S-N curve with system effects given in DNVGL RP C203 for traditional offshore applications

ℓweld

is length of weld subjected to the same stress range, typical length of one cylinder

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 24

Part 5 Chapter 8 Section 5

The two formulations for the estimate of the characteristic value of log10N for the system of ns cylinders are correspondingly denoted as Alternative 1 and Alternative 2:

is reference weld length with similar weld quality and fatigue strength as the tested specimen. 120 mm may be used if not otherwise documented by fatigue testing

ns

is number of similar connections subjected to the same stress range, typical number of cylinders.

The combined Miner sum for fatigue loads due to loading/unloading and dynamic ship loads is not to be higher than 1)

2)

0.2 (DFF = 5) with length effect and design S-N curve established as mean minus 2 standard deviations. The cylinders are assumed to be fabricated with enhanced control with respect to production tolerances. Out-of-roundness has not been specifically considered for the longitudinal welds. 0.33 (DFF = 3) with length effect and standard design S-N curves from DNVGL RP C203. Out-ofroundness and local stress concentrations are to be specifically considered in design, i.e. all local stresses are to be included in the fatigue stress range. This does not necessarily require enhanced control in fabrication of the cylinders.

The fatigue damage effects from filling and emptying of the containment cylinders and the damage contribution from support stresses originating from the accelerations of the ship in seagoing conditions can be combined as given in DNVGL RP C203 App.[D.3]. Guidance note: The main contribution to the fatigue loading comes normally from filling and emptying of the cylinders. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Table 1 Coefficient c(n) for estimation of characteristic values with confidence 95% Number of tests, n

c2(n) survival prob. 97.725%

c3(n) survival prob. 99.865%

2

32.2

46.0

3

9.24

13.7

5

5.01

7.29

7

4.09

5.96

10

3.45

5.05

12

3.26

4.72

15

3.07

4.45

20

2.88

4.19

25

2.75

4.00

30

2.65

3.91

50

2.48

3.66

100

2.32

3.44

∞

2.00

3.00

3.1.3 Additional fatigue analyses using fracture mechanics crack growth calculations shall be carried out for the cargo tank cylinders using mean plus 2 standard deviation values for the crack growth data (μ+2σ). The analysis shall be carried out for planar defects assumed located in both the longitudinal and circumferential welds of the cylinders. The calculated fatigue life for a crack to grow through the cylinder wall thickness shall be 3 times the design life, but not less than 75 years (i.e. using DFF = 3 and no system length effect). A realistic stress concentration factor relevant for the weld toe shall be applied. The assumed initial planar

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 25

Part 5 Chapter 8 Section 5

ℓref

The fracture mechanics assessments may be carried out according to e.g. BS 7910 Guide to methods for assessing the acceptability of flaws in metallic structures. 3.1.4 If the necessary number of load cycles for the crack to propagate through the wall thickness required in [3.1.3] cannot be shown, or if Leak-Before-Failure is to be used, it shall be documented that unstable fracture will not occur in the cylinder from a fatigue crack before a possible leak from the calculated through thickness crack can be detected and the tank pressure relieved (blown-down). Applied fracture toughness values shall be documented for the base material, heat affected zone and weld metal for the relevant operation temperature. 3.1.5 The supported areas of the cargo containment cylinders shall be included in the fatigue calculation required by [3.1.2], [3.1.3] and [3.1.4].

3.2 Cargo tank piping 3.2.1 The stresses in the cargo tank piping shall fulfil the requirements given in Ch.7 Sec.5 [11]. The stress calculation shall include all relevant loads given above including vibrations. The calculation of maximum stresses and stress range may be carried out according to ASME B31.3. The design principles given in Sec.6 [1.4] applies also for the cargo tank piping. 3.2.2 The cargo tank piping shall be subject to fatigue analysis. The S-N curve shall be applicable for the material, construction detail and state of stress considered. Model testing of details of piping as fabricated may be required. The S-N curve shall be based on the mean curve of log10N with the subtraction of 2 standard deviations from log10N. The Miner sum from combined dynamic loads and fatigue loads due to loading and unloading shall not be higher than 0.1. 3.2.3 Fatigue crack propagation calculations shall be carried out for the cargo tank piping. The analysis shall be carried out for defects assumed located in circumferential welds only as the piping shall be of a seamless type or equivalent. The leak-before-failure principle shall be used, i.e. a crack shall propagate through the thickness allowing gas detection and safe blow-down or venting of the affected cargo tank before a complete rupture takes place. Design criteria as for [3.1.3] apply. 3.2.4 The cargo tank piping shall be adequately supported so that the reaction force from a complete rupture of a pipe will not lead to rupture of other pipes by the damaged pipe hitting other pipes. At the same time sufficient flexibility shall be provided in order to allow the cylinders to expand due to pressure and horizontally movement of the cylinder nozzle due to accelerations and vibrations without causing excessive stresses in the piping system which might lead to yielding or fatigue problems. Cargo tank piping up to the cargo tank valve shall be of all welded construction. 3.2.5 All fittings in the cargo tank piping shall be of forged type. Alternative solutions may be considered by the Society.

3.3 Welding requirements 3.3.1 Welding procedure qualification Pre-production weldability testing shall be carried out for qualification of the tank material and welding consumable according to a weldability testing programme including bead on plate, Y-groove and also fracture toughness tests of base material, HAZ and weld metal. Metallographic examination shall be conducted to establish the presence of local brittle zones. The maximum and minimum heat inputs giving acceptable properties in the weld zones with corresponding preheat temperature, working temperatures and post weld heat treatment temperatures (if post weld heat treatment required) shall be determined for both fabrication and installation welding. The testing programme for the cargo tank cylinder shall be in accordance with

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 26

Part 5 Chapter 8 Section 5

defect shall reflect the largest non-detected defect during the non-destructive inspection carried out. The applied crack growth parameters shall be documented for the cylinder base material and its welds.

3.4 Pressure testing and tolerances Fabrication tolerances and hydraulic testing of the complete cargo tank shall be in accordance with DNVGL ST F101 or Ch.7 as applicable. Guidance note: A test pressure equal to 1.2 times the design pressure is considered appropriate. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.5 Non-destructive testing (NDT) All welds in cylinders and cargo tank piping shall be 100% NDT tested in accordance with an approved NDT program. Reference is made to [3.1.3] regarding required detectable crack size.

3.6 Post weld heat treatment All longitudinal welds in the cylinders shall be post weld heat treated or stress relieved by an equivalent procedure acceptable to DNV GL.

3.7 Prototype testing 3.7.1 A set of full scale (with respect to diameter, thickness, number of circumferential welds, including end-caps but not necessarily full length) fatigue and burst tests shall be performed. It shall be documented that the cylinder wall, end-caps and welding has sufficient reliability against fatigue and that the cylinder possesses sufficient burst resistance after twice the number of anticipated design lifetime pressure induced stress cycles. A minimum of 3 tests shall be performed. One burst test shall be carried out after having been subjected to twice the anticipated number of stress cycles and 2 fatigue tests to document that the fatigue capacity during the design lifetime is — 15 × the number of stress cycles for fatigue design analysis without length effect, and — 10 × the number of stress cycles for the cylinders when length effect has been explicitly included in the design analyses.

4 Composite type cargo tank 4.1 General 4.1.1 All general requirements from [1.1] apply also to composite tanks. 4.1.2 The composite cargo tanks addressed here are made of fibre reinforced plastic. A typical simplified pressure vessel with a laminate and inner and outer liner is shown in Figure 1. The inner liner is the fluid barrier. It may also be designed to carry part of the loads. The composite laminate carries the pressure loads alone or in combination with the inner liner. The fibres are typically carbon, glass or aramid. The plastic matrix is typically an epoxy or polyester. Other fibres and matrices may be used. Whatever material system is chosen the short term and long term material properties shall be sufficiently characterized. Requirements for the characterization of composite materials are given in DNVGL ST C501

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 27

Part 5 Chapter 8 Section 5

DNVGL ST F101. Relevant documentation may be agreed in lieu of weldability testing. Fracture mechanics testing at the minimum design temperature shall, however, be performed for the base material, heat affected zone and weld metal after being subjected to any post weld heat treatment. Weld production testing shall be carried out according to DNVGL ST F101.

Figure 1 Typical simplified composite pressure vessel 4.1.3 All metal parts shall be designed according to the requirements given in [3]. If the liner is made of polymeric materials DNVGL ST C501 can be used. Additional requirements are also given in [4.8] to [4.9]. 4.1.4 The dynamic short term loads due to ship motions shall be taken as the most probable largest loads the ship will encounter during its operating life (normally the characteristic load effect is defined as the 99% quantile in the distribution of the annual extreme value of the local response of the structure, or of the applied global load when relevant). Dynamic long term loads may be taken as realistic load sequences. 4.1.5 The requirements given here are mainly related to cylindrical cargo tanks. Requirements for coiled type cargo tank shall be specially considered. The requirements applicable for the cylinder type cargo tank shall be complied with as found relevant.

4.2 Cargo tank cylinder - calculations 4.2.1 As a minimum requirement, the composite tanks shall be designed for (not limited to) the potential modes of failures as listed in Table 2 for all relevant conditions expected during the various phases of its life. All failure mechanisms that can be related to the limit states shall be identified and evaluated. Table 2 Typical limit states for the tank system Limit state category

Limit state or failure mode

Failure definition or comments

Bursting

Membrane rupture of the tank wall caused by internal overpressure, possibly in combination with axial tension or bending moments.

Liquid tightness

Leakage in the tank system including pipe and components, caused by internal overpressure, possibly in combination with axial tension or bending moments.

Buckling

Buckling of the tank cross section and/or local buckling of the pipe wall due to the combined effect of bending, axial loads and possible external overpressure (when flooding).

Damage due to wear and tear

Damage to the inside or possibly to the outside of the tank during operation or installation, resulting into burst or leakage.

Ultimate limit state (ULS)

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 28

Part 5 Chapter 8 Section 5

Composite components. The outer liner is a protective layer against external loads/environments. It does typically not carry any loads.

Accidental limit state (ALS)

Fatigue limit state (FLS)

Limit state or failure mode

Failure definition or comments

Explosive decompression

Rapid expansion of fluid inside a material or interface leading to damage that may cause leakage or burst.

Chemical decomposition Corrosion

Chemical decomposition or corrosion of materials with time that leads to a reduction in strength, resulting into burst or leakage.

Same as ULS

Failure caused by accidental loads directly, or by normal loads after accidental events (damage conditions).

Impact

Damage introduced by dropped objects.

Fire

Resistance to fire.

Cooling down

Accidental quick release of the gas can cause cooling down of the damaged and possibly neighbouring tanks. Materials and structures should be able to operate under these conditions.

Fatigue failure

Excessive Miner fatigue damage or fatigue crack growth mainly due to cyclic loading, directly or indirectly.

Resonance

The effect of vibrations and resonance frequencies may cause fatigue and shall be considered.

4.2.2 The pressure used for calculating the composite lay-up is the design pressure defined in Sec.1 Table 3. The maximum operating pressure should be 5% or more below the design pressure. The ends and cylindrical part of the composite laminate shall be made in one piece. Special attention shall be given to all metal composite connections. These connections shall be designed and qualified according to DNVGL ST C501 Sec.7. 4.2.3 The cargo tank cylinder and all composite metal joints shall be subject to fatigue analysis. The S-N curve shall be established as described in [3.1.2]. The Miner sum (for both dynamic loads and fatigue loads due to loading and unloading) shall not be higher than 0.02. 4.2.4 Fatigue calculations shall be carried out for the laminates in the fibre directions and for all relevant interface properties as described in DNVGL ST C501. 4.2.5 The maximum and minimum temperatures of the cylinders shall be defined. Extreme and long term temperatures should be defined if necessary. Temperature changes due to pressure changes during loading, off-loading and blow down shall be considered. 4.2.6 All material properties shall be established for the relevant operating and extreme environments. 4.2.7 The cargo tank cylinders shall be supported as described in [3.1.5]. 4.2.8 Stresses (static and dynamic) from all sources shall be included in the calculations, like primary bending, membrane stress, thermal stresses and vibrations. The cargo containment cylinders at supports shall be included in the fatigue calculation required by [4.2.3]. 4.2.9 Different expansion coefficients for steel, composite and other materials shall be considered. 4.2.10 The resonance frequencies shall be checked, see also [1.1.5]. Vibrations from machinery and wave loading should not coincide with the resonance frequencies of the pressure vessel (filled or unfilled).

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 29

Part 5 Chapter 8 Section 5

Limit state category

relevant and γS = 1.0. Otherwise a system factor shall be documented. A value of γS = 1.10 can be used as a first approach. In some cases a system may consist of parallel components that support each other and provide redundancy, even if one component fails. In that case a system factor smaller than 1 may be used if it can be based on a thorough structural reliability analysis. Guidance note 1: In the case of a number of tanks connected in sequence, the failure of one section (i.e. plain pipe or end connector) is equivalent to the failure of the entire system. This is a chain effect in which any component of the sequence can contribute. As a consequence, the target safety of individual section should be higher than the target safety of the entire system, in order to achieve the overall target safety. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: A continuous spoolable tank has only two end connectors (one at each end). Failure of an end connector is also a system failure. However, since there are only two connectors it is not a chain effect and

γS = 1.0 can be used.

---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.3 Cargo tank piping 4.3.1 It is assumed here that piping is made of metal and the same requirements as given in [3.2] apply. 4.3.2 Composite piping may be considered on an individual basis.

4.4 Production requirements and testing after installation 4.4.1 Fabrication tolerances and hydraulic testing of the complete cargo tank shall be in accordance with DNVGL ST F101 Sec.7 or DNVGL ST C501 Sec.11 as applicable. Guidance note: A test pressure equal to 1.3 times the design pressure is considered appropriate. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.4.2 The cargo tanks shall be tested on the ship after installation as a final acceptance test. The test pressure shall be 1.3 times the design pressure.

4.5 Full scale prototype pressure testing and tolerances 4.5.1 A set of full scale (with respect to diameter, thickness, number of circumferential welds, including endcaps but not necessarily full length) fatigue and burst tests shall be performed and it shall be documented that the cylinder wall, end-caps and welding have sufficient reliability against fatigue and that the cylinder possesses sufficient burst resistance. Possible damage during installation or operation shall be included in the design tests, see also [4.5.4]. The sequence of the failure modes in the test shall be the same as predicted in the design. If the sequence is different or if other failure modes are observed, the design shall be carefully re-evaluated. Minimum test requirements are given in Table 3. 4.5.2 Additional testing should be done whenever uncertainties in the analysis cannot be resolved. These uncertainties may be related to the structural analysis, boundary conditions, modelling of local geometry, material properties, failure modes, properties of interfaces, etc. The procedure given in DNVGL ST C501 should be followed for testing.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 30

Part 5 Chapter 8 Section 5

4.2.11 The safety factors for all load bearing metal parts shall be the same as given in [3]. The safety factors for the composite laminate are given in DNVGL ST C501 and safety class high shall be chosen. The partial safety factors are given for the entire system. The effect of combining various components in a system is described by the system effect factor γS. If the components do not interact the system effect is not

Guidance note: Testing with gas requires special safety precautions during testing and it may not be possible to carry out the tests on board the vessel. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.5.4 The tank shall be exposed to typical impact damage, like damage from a dropped hammer etc. Subsequently a pressure test and a fatigue test shall be carried out. The testing may be combined with the tests specified in Table 3. 4.5.5 The specimen geometry for testing may be chosen to be different from the actual under certain conditions. Specimens may be shorter than in reality. If shorter specimens are chosen, the free length of the tank pipe between end-fittings should be at least 6 × diameter. Scaled specimens may be used if analytical calculations can demonstrate that: — all critical stress states and local stress concentrations in the joint of the scaled specimen and the actual tank are similar, i.e. all stresses are scaled by the same factor between actual tank and test specimen — the behaviour and failure of the specimen and the actual tank can be calculated based on independently obtained material parameters. This means no parameters in the analysis should be based on adjustments to make large scale data fit — the sequence of predicted failure modes is the same for the scaled specimen and the actual tank over the entire lifetime of the tank — an analysis method that predicts the test results properly but not entirely based on independently obtained materials data, may be used for other joint geometry. In that case it should be demonstrated that the material values that were not obtained by independent measurements can also be applied for the new conditions. Tests on previous tanks may be used as testing evidence if the scaling requirement given above are fulfilled. Materials and production process should also be identical or similar. Similarity should be evaluated based on the requirements in DNVGL ST C501 Sec.4. Table 3 Summary of test requirements Name of test

Description

Reference

Design phase Pressure test

1 test to failure

[4.5.6]

Pressure fatigue of tank

2 tests to 5 × actual number of cycles or survival test to about 100 000 cycles, followed by burst test.

Stress rupture test of tank if matrix properties are critical or fibres can creep

2 tests to 50 × actual lifetime or survival test to about 1 000 hours

If the inner liner is bonded to the laminate

Test bond between liner and laminate

[4.5.10]

If impact requirement

Impact tests

[4.5.11]

Process Prototype Testing

System test

[4.5.12]

[4.5.7] and [4.5.8]

[4.5.9]

After fabrication Pressure test

Test to 1.3 times design pressure for each tank component

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

[4.4.1]

Page 31

Part 5 Chapter 8 Section 5

4.5.3 Testing may be done at room temperature and with water as a pressure medium if the effect of temperature changes and fluid changes can be well described. If the effect of changing the environmental conditions is uncertain, testing should be carried out in the worst conditions and possibly with gas.

Description

System acceptance test

Test to 1.3 times design pressure for each tank component

Reference [4.4.2]

4.5.6 Burst pressure test: A burst test shall be done and the burst pressure shall be at least the predicted μ -σ, where μis the mean prediction and σis standard deviation of the predicted burst pressure. If more than one test is done the requirements are given in DNVGL ST C501 [10.3.2]. 4.5.7 Pressure fatigue testing: Fatigue tests shall be carried out with a typical pressure load sequence. Axial tension or bending should be added if relevant. The most relevant test should be found by evaluating the design analysis. At least two survival tests shall be carried out. The specimen shall not fail during the survival test and it shall not show unexpected damage. The requirements to the testing are: — Tests shall be carried out up to five times the maximum number of design cycles with realistic amplitudes and mean loads that the component will experience. 5 — If realistic pressure sequences cannot be tested or if the anticipated lifetime exceeds 10 cycles, the test procedure may be changed as given in DNVGL ST C501 [10.3.3]. — All tests shall be completed with a pressure test. The failure load or pressure shall be at least the predicted μ - σ, where μ is the mean prediction and σ is one standard deviation of the predicted load. 4.5.8 In some cases high amplitude fatigue testing may introduce unrealistic failure modes in the structure. In other cases, the required number of test cycles may lead to unreasonable long test times. In these cases an individual evaluation of the test conditions should be made that fulfils the requirements of [4.5.7] as closely as possible. 4.5.9 Stress rupture testing: Only if the performance of the metal composite interface depends on matrix properties or adhesives, or if the fibres in the laminate can creep, long term static testing should be performed. Two survival tests should be carried out. Stress rupture tests should be carried out with a typical load sequence or with a constant load. If a clearly defined load sequence exists, load sequence testing should be preferred. The specimen should not fail during the survival test and it should not show unexpected damage. The requirements to the test results are: — Tests should be carried out up to five times the maximum design life with realistic mean pressure loads that the component will experience. If constant load testing is carried out tests should be carried out up to 50 times the design life to compensate for uncertainty in sequence effects. — If the anticipated lifetime exceeds 1000 hours testing up to 1000 hours may be sufficient. The load levels 3 should be chosen such that testing is completed after 10 hours. The logarithms of the two test results shall fall within μ -σ of the logarithm of the anticipated lifetime, where μ is the mean of the logarithm of the predicted lifetime and σ is one standard deviation of the logarithm of the predicted lifetime, both interpreted from a log(stress) - log(lifetime) diagram for the anticipated lifetime. If more tests are made the requirements are given in DNVGL ST C501 [10.3.3]. — All tests should be completed with a pressure test. The failure load or pressure should be at least the predicted μ -σ, where μ is the mean prediction and σ is one standard deviation of the predicted load. 4.5.10 Liner bond testing: If the design relies on a bond between liner and composite laminate, the quality of the bond shall be tested. Tests can be done on the pipe or representative smaller specimens. If the laminate may have cracks, it shall be ensured that the cracks do not propagate into the liner or reduce the bond quality between liner and laminate. 4.5.11 Impact testing: The tank should be exposed to typical impact damage, like damage from a dropped hammer etc. Subsequently a pressure test and a fatigue test should be carried out. The testing may be combined with the tests specified above.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 32

Part 5 Chapter 8 Section 5

Name of test

4.6 Non-destructive testing (NDT) Composites laminates shall be inspected according to DNVGL ST C501 [12.2].

4.7 Composite - metal connector interface 4.7.1 The interface between the metal connector and the composite pipe is a critical part of the tank design. The interface is basically a joint and all general requirements given in DNVGL ST C501 Sec.7 Joints should be considered. 4.7.2 The composite metal connector interface shall be strong enough to transfer all loads considered for the connector and the pipe section. 4.7.3 Internal or external pressure on the tank system may be beneficial or detrimental to the performance of the joint. This effect shall be considered in the analysis. 4.7.4 Creep of any of the materials used in the joint may reduce friction, open up potential paths for leakage or lead to cracks. Effects of creep shall be considered. Guidance note: It is highly recommended to design the joint in a way that it also functions if the matrix of the composite laminate is completely degraded. In that case the joint can perform as long as the fibres are intact and sufficient friction between fibres and the fibre metal interface exists. Such a joint does not rely on the usually uncertain long-term properties of the matrix. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.7.5 Metal parts should be designed in a way that they do not yield to ensure no changes in the geometric arrangement of the joint. If any yielding can occur a non-linear analysis shall be done taking all relevant load histories and accumulated plastic deformations into account. Local yielding in thin sections or near welds shall be evaluated. 4.7.6 Possible effects of corrosion on metals and interfaces shall be evaluated. 4.7.7 Possible galvanic corrosion between different materials shall be considered. An insulating layer between the different materials can often provide good protection against galvanic corrosion. 4.7.8 Leak tightness of the joint shall be evaluated. In particular possible flow along interfaces should be analysed.

4.8 Inner liner 4.8.1 Most composite tanks have an inner liner as a fluid barrier. The liner may also carry parts of the pressure load. This inner liner is typically made of metal or polymeric materials. 4.8.2 It shall be shown that the inner liner remains fluid tight throughout the design life, if it is used as a fluid barrier. 4.8.3 The inner liner may contribute to the overall stiffness and strength of the tank system depending on its stiffness and thickness.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 33

Part 5 Chapter 8 Section 5

4.5.12 Process prototype testing shall be carried out to document that the system functions as specified with respect to accumulation and disposal of liquids. It shall be verified that liquid hammering does not occur in the piping system during any operation. Where it is impractical to perform full scale testing, successful operation can be simulated computationally and in small scale testing to provide adequate assurance of functionality.

4.8.5 If the inner liner is designed to carry also part of the pressure loads all requirements from [4.8.4] shall be fulfilled. In addition, the load bearing capability of the liner shall be checked according to [3]. The inner liner needs to deform somewhat and press against the composite laminate before the laminate can support the liner and reduce the loads in the liner. This effect shall be considered. Its magnitude depends on how tightly the laminate is wound around the liner and on how stiff the laminate is in relation to the liner. 4.8.6 The inner liner should be operated in its elastic range. Neither operational conditions nor test conditions should bring it to yield. An exception is the first pressure loading called autofrettage. Autofrettage is common practice to pressurize a vessel initially at the manufacturer to such high pressures that the inner liner yields. This creates a tight fit between the liner and laminate. The liner will subsequently be compressed by the outer laminate when the high pressure is removed. 4.8.7 Autofrettage of the inner liner is common practice. The tank is pressurized initially at the manufacturer to such a high pressure that the inner liner yields. After removing the pressure the inner liner will be compressed by the outer laminate. This procedure ensures a tight fit between inner liner and laminate. It shall be shown that the inner liner does not buckle due to the compressive loads. The yielding of the inner liner during autofrettage also causes the liner’s welds to yield. This may reduce stress concentrations, but it can also cause local thinning around the weld. Any thickness variations in the inner liner may cause localised yielding. The weld zone may have lower yield strength than the main part of the inner liner. Due to this the inner liner may yield locally close to the welds. The strain in the localised yield region can be very high, possibly leading to instant rupture, lower fatigue performance, enhanced creep. The inner liner and its welds shall be analysed taking all these effects into account. Guidance note: A small thin area in the inner liner can be worse than a larger thin area, because the inner liner may only deform by yielding in the thin section. In that case the small thin section will have much higher strains than the large section, if the total deformation is the same. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.8.8 If the inner liner material can creep, then creep will happen especially in the thin highly strained regions. The effect of creep with respect to fatigue, stress rupture and buckling shall be evaluated. 4.8.9 If the inner liner is under compression, local yielding may create deformations resulting in local or global buckling. 4.8.10 Buckling of the liner due to hoop compression shall be considered as a potential failure mechanism. The following two phenomena should be considered as a minimum: — Rapid decompression causes a pressure to build up suddenly between the liner and the composite tank tube, at the same time as the pressure inside the liner suddenly drops. This effect can happen if gas or liquid can diffuse through the inner liner and accumulate in the interface between liner and laminate or inside the laminate. This effect can be ignored for metal liners, since they are diffusion tight, provided no other diffusion path through seals etc. exists in the system. — As a result of the sustained internal pressure, the liner yields plastically (or undergoes creep deformation) in tension in the hoop direction. Decompression causes the composite tank cylinder to contract, compressing the liner and causing it to buckle. This effect can be prevented by using initially the autofrettage process ([4.8.7]) and by keeping the liner below yield during operation. 4.8.11 Inner liner specifications with respect to acceptable thickness variations, weld quality, and maximum misalignments should be consistent with the worst cases evaluated in the analysis.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 34

Part 5 Chapter 8 Section 5

4.8.4 If the inner liner is only a fluid barrier it usually follows the deformations of the main load bearing laminate. It shall be shown that the inner liner has sufficiently high strains to failure and yield strains to follow all movements of the tank system.

4.8.13 The liner may be bonded to the composite laminate or it may be un-bonded. 4.8.14 A different layer of material may also be placed between the laminate and the liner. 4.8.15 All possible failure modes of the interface and their consequence to the performance of the system shall be evaluated. 4.8.16 If a bond is required between laminate and liner, for example to obtain good buckling resistance of the liner, the performance of the bond shall be tested [4.5.10]. 4.8.17 If interfaces only touch each other friction and wear should be considered, see DNVGL ST C501 [6.13]. 4.8.18 If the liner is not totally fluid tight, fluids may accumulate between interfaces. They may accumulate in voids or de-bonded areas and or break the bond of the interface. They may also accumulate in the laminate. The effect of such fluids should be analysed. The fluid should diffuse more rapidly through the laminate than through the inner liner, and more rapidly through the outer liner then through the laminate. Possible effects of rapid decompression of gases should be considered. The effect of the slight gas leaks due to diffusion shall be considered in the system analysis. 4.8.19 If the laminate may have matrix cracks, but the liner shall not crack (or vice versa), it shall be shown that cracks cannot propagate from one substrate across the interface into the other substrate. Possible debonding of the interface due to the high stresses at the crack tip should also be considered. 4.8.20 It is recommended to demonstrate by experiments that cracks cannot propagate across the interface from one substrate to the other. It should be shown that by stretching or bending both substrates and their interface that no cracks form in the one substrate even if the other substrate has the maximum expected crack density. Guidance note: A weak bond between the substrates is beneficial to prevent crack growth across the interface. However, it means that the risk of de-bonding increases. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.8.21 The inner liner should be strong enough to withstand possible shear, scraping and torsional loads from equipment running inside tank. 4.8.22 The inner liner shall be resistant to the internal environment. Possible accumulation of water or other liquids on the bottom of the tank shall be considered. A possible combination of water and H2S from the gas shall also be considered.

4.9 Outer liner 4.9.1 An outer liner is usually applied for keeping out external fluids, for protection from rough handling and the outer environment and for impact protection. 4.9.2 If no outer liner is applied the outer layers of the laminate have to take the functions of the outer liner. 4.9.3 The outer liner material shall be chosen so that it is resistant to the external environment, e.g., seawater, temperature, UV etc.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 35

Part 5 Chapter 8 Section 5

4.8.12 Polymeric inner liners, like thermoplastic inner liners may be evaluated against the yield criterion in DNVGL ST C501 [6.6].

4.9.5 Outer liners are not exposed to autofrettage. They should be kept below yielding. 4.9.6 Resistance of the outer liner to handling and the external environment shall be considered. The outer liner may get some damage from handling, but the structural layer underneath should not be affected. 4.9.7 The performance requirements to the outer liner should not be affected by a possible impact scenario. 4.9.8 If fluids can diffuse through the inner liner into the load bearing laminate the outer liner may suffer from blow out if the external pressure is lower than the pressure inside the laminate. Blow out can be prevented by a venting mechanism. 4.9.9 Blow out will also not happen if it can be shown that the fluids will diffuse from the laminate through the outer liner into the external environment more rapidly than from the inside of the tube through the inner liner into the laminate. In addition, the remaining fluid concentration should be low enough that even under low external pressure the outer liner cannot blow out.

4.10 Installation 4.10.1 A procedure for handling of the composite cargo tanks shall be submitted for information. The procedure shall describe how the tanks will be handled to avoid external impacts and point loads. 4.10.2 The installation procedure shall as a minimum address the following issues: — — — — —

How can impact loads be avoided? How can impact loads be detected, if they should happen? What are the loads during installation and handling, point loads should be avoided? What shall be done in case of fire during installation? What is the effect of weld spatter, sparks, naked flames, how can it be avoided?

Possible excessive moments and forces from the manifold system during installation should be addressed.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 36

Part 5 Chapter 8 Section 5

4.9.4 If the outer liner is exposed to UV radiation in service or during storage, it should be UV resistant.

1 General 1.1 Bilge, ballast fuel oil piping For piping systems in cargo area not forming a part of the cargo piping the requirements given in Pt.4 Ch.1, Pt.4 Ch.6 and Ch.7 Sec.5 apply. Piping systems common to multiple holds shall be arranged so that release of gas from one hold space shall not leak into other hold spaces.

1.2 Cargo piping, general 1.2.1 Structure and supports shall be suitably shielded from leak from flanges and valves and other possible leak sources if the cool down effect cannot be shown to be negligible. 1.2.2 If cargo piping enters enclosed spaces above main deck in process area, these spaces shall be provided with overpressure protection in case of high pressure leak or explosion.

1.3 Cargo valves 1.3.1 All remotely operated valves shall be capable of local manual operation. 1.3.2 The cargo tanks shall be connected to the cargo piping in accordance with the following principles: — Each cargo tank shall be segregated from the cargo piping by a manually operated stop valve and a remotely operated valve in series. A combined manually and remotely operated stop valve is acceptable provided means are available to check the integrity of the valve. — The loading/unloading connection point shall be equipped with a manually operated stop valve and a remotely operated valve in series. — The remotely operated cargo tank valves and load/unload valves required above shall have emergency shut-down (ESD) functions. The valves shall close smoothly so that excessive pressure surges do not occur. — The ESD valves shall be arranged so that they close automatically in case of high pressure, sudden pressure drop during loading/unloading operations and in the event of fire. The ESD valves shall be arranged to be operated manually from cargo control room and other suitable locations. — The cargo compressors shall shutdown automatically if the ESD system is activated.

1.4 Cargo piping design 1.4.1 The cargo piping system shall as a minimum meet the requirements given in Pt.4 Ch.6 and Ch.7 Sec.5 or a standard acceptable to the Society with the following additional requirements: — The design temperature shall be the minimum temperature achieved during all normal and emergency procedures e.g. loading/unloading and pressure relieving shall be considered. — The design pressure is the maximum pressure to which the system may be subjected to in service e.g. the set point of the safety relief valve, see Sec.7 [1.1]. — The pipes shall be seamless or equivalent. — Only butt welded and flanged connections of the welding neck type are allowed. Flange connections shall be limited as far as possible. — All butt welds shall be subject to 100% radiographic testing.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 37

Part 5 Chapter 8 Section 6

SECTION 6 PIPING SYSTEMS IN CARGO AREA

1.4.2 Procedures for cargo transfer including emergency procedures shall be submitted for approval. The procedures shall address potential accidents related cargo transfer, and information regarding emergency disconnection, emergency shutdown, communication with offshore/onshore terminals etc. shall be included.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 38

Part 5 Chapter 8 Section 6

— Welding procedure tests and production weld test are required for cargo piping as specified in Ch.7 Sec.6 [5] — After assembly the piping system shall be hydrostatic pressure tested to at least 1.5 times design pressure prior to installation. — After assembly on board the complete cargo piping shall be subjected to a leak test using air, halides or other suitable medium according to an approved procedure. — The effects of vibrations imposed on the piping system shall be evaluated. — A complete stress analysis for each branch of the piping system shall be conducted according to ANSI/ ASME B31.3.

1 General 1.1 Cargo piping A pressure relief valve for preventing overpressure in the cargo piping shall be provided. The set point of the safety relief valve shall not be more than the design pressure of the cargo piping, less the tolerance of the relief valve.

1.2 Cargo tanks 1.2.1 The cargo tanks shall be provided with a blow down system and an automatic pressure relief system. The system shall ensure safe collection and disposal of pressurised gas during normal operation and during emergency conditions. The gas from the vent may be cold vented or ignited. If there are provisions for cold venting a gas dispersion analysis shall be conducted in order to evaluate the extent of the gas dangerous area. 1.2.2 The blow down system shall meet the following principles: — The blow down system shall provide means for pressure relieving of individual cargo tanks due to leakage. — The blow down system shall be provided with remote control for blowing down individual cargo tanks. — It shall be possible to determine which of the cargo tanks is leaking based on input from e.g. gas detection system, pressure sensors in cargo tank sections, temperature in hold space, and pressure in hold space. — Cold venting will be acceptable provided it does not impose an unacceptable risk. There shall be two blow down valves fitted in series with a common control signal. One of the valves may be common for all cargo tanks. It shall be possible to check the integrity of the valves. — The capacity of the blow down system shall be sufficient to ensure that rupture of cargo tank or cargo tank piping will not occur in case of heat input from a fire or cool down from a gas leak. Guidance note: The capacity of the system should be based on evaluation of: —

system response time

—

heat input from defined accident scenarios

—

material properties and material utilisation ratio

—

other protection measures, e.g. active and passive fire protection

—

system integrity requirements.

Fire water systems are not normally regarded as reliable protection measures for systems exposed to jet fires. Physical separation and passive fire protection should be the preferred means of preventing escalation. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.3 The cargo tanks shall be provided with a pressure relief system appropriate to the design of the cargo tank. The set point of the safety relief valve shall not be higher than the design pressure of the cargo tanks, less the tolerance of the relief valve. 1.2.4 If it proves impractical to install the blow down valves required in [1.2.2] and the safety relief valve required in [1.2.3], then alternative measures may be considered. These include high integrity pressure protection systems (HIPPS) where the cargo valve may also serve as blow down valve and a safety relief valve. The acceptability of such systems shall be considered on a case by case basis and will be dependent upon demonstration of adequate reliability and response of the complete system from detector to actuated

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 39

Part 5 Chapter 8 Section 7

SECTION 7 OVERPRESSURE PROTECTION OF CARGO TANKS AND CARGO PIPING SYSTEM

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 40

Part 5 Chapter 8 Section 7

device(s). The reliability target shall be an order of magnitude higher than critical failure of a typical relief device.

1 General 1.1 General Arrangements for gas freeing shall be provided for all parts of the cargo system. A detailed procedure describing this routine shall be included in the cargo handling manual and submitted to the Society for review.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 41

Part 5 Chapter 8 Section 8

SECTION 8 GAS-FREEING OF CARGO CONTAINMENT SYSTEM AND PIPING SYSTEM

1 General 1.1 General 1.1.1 The ship shall meet the requirements given in Ch.7 Sec.8 and Ch.7 Sec.12 as applicable. 1.1.2 Shut down philosophy for gas detection in cargo area, air ventilation intakes for accommodation and machinery spaces shall be evaluated and submitted for information.

1.2 Ventilation in hold spaces In order to provide for aeration of hold space an efficient ventilation system shall be provided. The ventilation system shall discharge to outlets ensuring safe environment for crew during release of inert gas.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 42

Part 5 Chapter 8 Section 9

SECTION 9 MECHANICAL VENTILATION IN CARGO AREA

1 General 1.1 General The ship shall meet the requirements for gas carriers given in Ch.7 Sec.11 with additional requirements specified in this section. For new concepts the fire loads shall be determined as a part of the quantitative risk assessment referred to in Sec.1 Table 3.

1.2 Structural fire preventive measures 1.2.1 Exterior boundaries of superstructures and deckhouses, and including any overhanging decks, shall be A-60 fire-protected for the portions facing the cargo area, the fuel oil storage wing tanks area and the process plant area, and for 3 metres away of any such boundary line. 1.2.2 If a process plant or any other potential release sources with gas under high pressure is located in the vicinity of accommodation, additional means of fire protection shall be considered. Guidance note: Additional fire protection may be: —

H-60 insulation of the boundaries described in [1.2.1]

—

Physical protection preventing a jet from a gas leak exposing accommodation. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.3 Hold space covers facing the process area shall be protected from the process area by a transverse firewall of not less than H-0. Hold space covers facing the engine room area and flare mast aft shall be constructed with a transverse fire class division of not less than A-0. Hold space covers shall have: — fire integrity to withstand exposure of a standard fire test used for A-class divisions with exposure from outside — surface flammability characteristics according to IMO resolution A.653(16) (towards weather deck) — sufficient strength and tightness to ensure effective inert atmosphere within hold space for one hour. 1.2.4 Hold spaces below the weather deck shall be protected from the turret area or process area by A-0 class division. For cargo tanks made of materials with fire resistance properties not equivalent to steel, the hold space cover shall be insulated to “A-60” class standard. In addition, hold space covers which are facing a process area or equipment with pressurised hydrocarbons shall be insulated to “H-60” class standard. 1.2.5 Accommodation, service spaces and engine room below the weather deck shall be separated from the process area, turret and cargo holds by means of cofferdams. The minimum distance between the bulkheads shall be 600 mm. 1.2.6 Any external boundaries of the engine room or service spaces, casings and the vent mast shall be made of steel. 1.2.7 Hold space covers or other essential areas or equipment which may be exposed to heat loads from an ignited leak from the cargo tanks/cargo piping shall be adequately protected for the time it takes to depressurise the cargo tanks.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 43

Part 5 Chapter 8 Section 10

SECTION 10 FIRE PROTECTION AND EXTINCTION

— They shall be constructed of steel or other equivalent material. — They shall be suitably stiffened. — They shall be constructed as to be capable of preventing the passage of gas, smoke and flames up to the end of the two-hour standard test for hydrocarbon fires. The relevant exposure model is implemented in the revised edition of ISO 834 (HC curve). — They shall be insulated with approved non-combustible materials or equivalent passive fire protection such that the average and maximum temperature of the unexposed side will not rise to more than 140°C and 180°C respectively above the original temperature, within the time listed below: class H-120 120 minutes class H-60 60 minutes class H-0 0 minutes.

1.3 Means of escape 1.3.1 Means of escape shall be provided from the engine room or service spaces to accommodation by means of enclosed shelter, preferably without having to be exposed to the weather deck. 1.3.2 Escape routes shall be arranged from the process area and other working zones in the cargo area to the muster area in the accommodation. 1.3.3 The transverse firewalls required in [1.2.1] shall provide protection against heat radiation for lifeboats.

1.4 Firefighter’s outfit 1.4.1 4 sets of firefighter’s outfits shall be placed in 2 separate fire stations, within the accommodation. 1.4.2 For concepts where the cargo area is dividing the accommodation and engine room or service spaces, 2 sets of firefighter’s outfits are required in the engine room or service spaces in addition to the sets required in [1.4.1].

1.5 Fire main 1.5.1 The basic requirements for fire pumps, hydrants and hoses, as given in SOLAS Ch. II-2/10.2, apply with the additional requirements given in [1.5.2] to [1.5.8]. 1.5.2 The arrangement shall be such that at least 2 jets of water, not emanating from the same hydrant, are available, one of which shall be from a single length of hose that can reach any part of the deck and external surfaces of the hold space covers. The minimum pressure at the hydrants with 2 hoses engaged shall be 0.5 MPa. Hose lengths shall not exceed 33 m. 1.5.3 The fire main shall be arranged either as: — a ring main port and starboard or — as a single line along the centre line through the cargo area provided the fire main is shielded from possible jet fire occurring from within the cargo piping. 1.5.4 Two main fire pumps shall be installed, each with 100% capacity. One pump shall be located forward of the cargo area and one pump aft of the cargo area and both pumps shall be arranged with remote control from both the bridge and the engine room.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 44

Part 5 Chapter 8 Section 10

1.2.8 Divisions formed by bulkheads and decks which comply with the following are regarded as Class H fire division:

1.5.6 Remote controlled isolation valves shall be arranged on the weather deck at each end of the fire main leading into the cargo or process area. The isolation valves shall be on the protected side of the fire wall or boundary. Manual operated stop valves shall be provided between each cargo hold space, and the distance between the valves shall not exceed 40 m. 1.5.7 All pipes, valves, nozzles and other fittings in the fire-fighting system shall be resistant to corrosion by seawater and to the effect of fire. 1.5.8 Mooring equipment positioned within gas dangerous zone shall be protected by a water sprinkler 2 system with a capacity of not less than 5 litres/m /minute. The sprinkler system shall be activated prior to any simultaneously use of the mooring equipment and cargo handling. If only one side of the mooring equipment is used at a time, the capacity for the water supply may be based on one side in operation only. The water sprinkler system may be served from the fire main. 1.5.9 The cargo load and unload area on the open deck shall be covered by water monitors which can be remotely controlled from a safe location.

1.6 Dual agent (water and powder) for process and load/unload area 1.6.1 The system shall be capable of delivering water and powder from at least two widely separated connections to the process area, cargo load and unload area and any other high fire risk areas located on the open deck. The length of the hoses shall be 25 m to 30 m. 1.6.2 Water supply may be taken from the main fire pumps and fire main if the added capacity of the system is included in capacity calculation for the main fire pumps. Powder shall be arranged in two separate units, each with the following discharge capacities: — 3.5 kg/s powder for not less than 60 seconds for one hand held hose.

1.7 Water spray 1.7.1 Water spray is not an acceptable means for complying with the minimum structural fire integrity given in [1.2]. 1.7.2 The following shall be protected by water spray: — — — — — — —

process area turret unprotected and pressurised cargo tank/deck piping emergency shut down (ESD) valves other important equipment for controlling the pressure in the cargo tanks due to fire the part of accommodation facing the cargo area external bulkheads of hold space covers facing the engine room and the flare mast.

1.7.3 The system shall be capable of covering all areas mentioned in [1.7.2] with a uniformly distributed 2 2 water spray of at least 10 litre/m per minute for horizontal projected surfaces and 4 litre/m per minute for vertical surfaces.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 45

Part 5 Chapter 8 Section 10

1.5.5 Both main fire pumps shall at any time during operation, when the ship is not gas-free, be available for start and delivery of water. The fire main shall be pressurised for immediate delivery of water at hydrants for engaging at least two effective jets of water onto the weather deck. The fire pumps shall start automatically upon low pressure detection in the fire main.

1.7.5 The water spray main shall be arranged either as: — a ring main port and starboard or — as a single line along the centre line through the cargo area provided the fire main is shielded from possible jet fire occurring from within the cargo piping. 1.7.6 Both water spray pumps shall be available for immediate start up and delivery of water. 1.7.7 2 water spray pumps shall be installed, each with 100% capacity. One pump shall be located forward of the cargo area and one pump aft of the cargo area and both pumps shall be arranged with remote control from both the bridge and the engine room. 1.7.8 Each water spray pump capacity shall be based on simultaneous demand for water spray to all areas required in [1.7.2], [1.7.3] and [1.7.4]. 1.7.9 Remote controlled isolation valves shall be arranged on the weather deck at each end of the fire main leading into the cargo or process area. The isolation valves shall be on the protected side of the fire wall or boundary. Manual operated stop valves shall be provided between each cargo hold space, and the distance between the valves shall not exceed 40 m.

1.8 Spark arrestors Exhaust outlet from internal combustion machinery and boilers shall be provided with spark arrestors.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 46

Part 5 Chapter 8 Section 10

1.7.4 The outlets of gas disposal systems, e.g. flare, cold vent or pressure relief valves shall be led to an area where radiation, heat or gases will not cause any hazard to the vessel, personnel or equipment. The heat radiation from the flare towards the cargo holds or other important equipment or areas shall be calculated to verify that the heat load does not lead to high temperatures in the cargo holds or equipment failure. The flare shall comply with API RP521 or equivalent.

Part 5 Chapter 8 Section 11

SECTION 11 ELECTRICAL INSTALLATIONS 1 General 1.1 General The ship shall meet the requirements given in Ch.7 Sec.10 as applicable.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 47

1 General 1.1 General 1.1.1 The ship shall meet the applicable requirements given in Ch.7 Sec.13 with the additional requirements given in this section. 1.1.2 Alarms shall be located on the navigating bridge and in the cargo control room. 1.1.3 Means for detection of moisture and H2S at the load/unload or shore connection shall be provided. 1.1.4 As a minimum the following location or spaces shall be monitored for gas: — — — — — —

suitable positions in each hold space deck piping (line sensors) ventilation inlets for gas safe spaces ventilation outlets for gas dangerous spaces air inlets to machinery spaces manifold area.

1.1.5 As a minimum the following location or spaces shall be fitted with pressure indicators and alarm: — each hold space — each cargo tank — cargo piping at load/unload connection. 1.1.6 Temperature sensors and oxygen indicators shall be fitted in the hold space. 1.1.7 Means for temperature measurement of the cargo within the cargo tanks shall be provided. 1.1.8 The temperature in the cargo tanks shall be monitored at a representative location during pressure relief, e.g. during unloading, blow-down. It shall be controlled that the temperature does not fall below the minimum design temperature.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 48

Part 5 Chapter 8 Section 12

SECTION 12 CONTROL AND MONITORING

Part 5 Chapter 8 Section 13

SECTION 13 TESTS AFTER INSTALLATION 1 General 1.1 General All systems shall be tested before the ship is taken into service.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 49

1 General 1.1 General The pressure in the cargo tanks, after filling, shall be limited so that the pressure does not increase above 95% of the design pressure at any time during transport or unloading taking into account: — for a system without cooling, the ambient temperature conditions given in Ch.7 Sec.7 [2] — for a system provided with a cooling system, the capacity of the cooling system and the ambient temperature conditions given in Ch.7 Sec.7 [2].

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 50

Part 5 Chapter 8 Section 14

SECTION 14 FILLING LIMITS FOR CARGO TANKS

1 General 1.1 General 1.1.1 The gas shall have a water dew point that during all operation modes does not lead to formation of hydrates or corrosion due to free water in the system. 1.1.2 Sour services shall be handled in compliance with supplementary requirements in the Society's document DNVGL ST F101.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 51

Part 5 Chapter 8 Section 15

SECTION 15 GAS SPECIFICATION

Part 5 Chapter 8 Section 16

SECTION 16 IN SERVICE INSPECTION PLAN 1 General 1.1 General 1.1.1 An inspection and monitoring philosophy shall be established, and this shall form the basis for a detailed inspection and monitoring program. 1.1.2 For the cylinder type cargo tank the program shall as a minimum address: — — — — — — —

number of cargo tank cylinders to monitor inspection tools and accuracy periodical surveys NDT requirements destructive testing of cargo tank cylinders if found necessary cargo tank piping, fittings and supports cargo piping, fittings and supports.

The inspection plan shall ensure that cracks and corrosion are detected with high reliability.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 52

Part 5 Chapter 8 Changes – historic

CHANGES – HISTORIC There are currently no historical changes for this document.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch8. Edition October 2015, amended July 2016 Compressed natural gas tankers

DNV GL AS

Page 53

DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification and technical assurance along with software and independent expert advisory services to the maritime, oil and gas, and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our 16 000 professionals are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition January 2018

Part 5 Ship types Chapter 9 Offshore service vessels

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the January 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.9. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018 Topic Requirements to offshore gangways

Updated requirements to DP

Reference

Description

Sec.6 [4.1]

The class notation CRANE is made mandatory. Removed certification requirement for crane as this is now covered by notation CRANE.

Sec.6 [4.2]

The class notation Walk2work is made mandatory.

Sec.6 [5.1]

Changed wording from "shall be built .. according to class notation.." to "shall .. have class notation..".

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 3

Part 5 Chapter 9 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................... 8 1 Introduction.........................................................................................8 1.1 Introduction..................................................................................... 8 1.2 Scope..............................................................................................8 1.3 Application....................................................................................... 8 2 Class notations.................................................................................... 9 2.1 Ship type notations.......................................................................... 9 2.2 Additional notations........................................................................ 10 3 Definitions..........................................................................................11 3.1 Terms............................................................................................ 11 4 Documentation...................................................................................11 4.1 Documentation requirements............................................................11 5 Certification....................................................................................... 15 5.1 Certification requirements................................................................ 15 6 Testing............................................................................................... 17 6.1 Testing during newbuilding...............................................................17 Section 2 Offshore service vessels........................................................................18 1 Introduction.......................................................................................18 1.1 Introduction................................................................................... 18 1.2 Scope............................................................................................ 18 1.3 Application..................................................................................... 18 2 Hull.................................................................................................... 18 2.1 Loads............................................................................................ 18 2.2 Hull local scantling.......................................................................... 19 2.3 Ship’s sides and stern..................................................................... 19 2.4 Weather deck for cargo................................................................... 19 2.5 Stow racks..................................................................................... 20 2.6 Primary supporting members........................................................... 20 3 Hull local scantling for ships assigned class notation Offshore service vessel(+).................................................................................. 23 3.1 Ship's sides and stern..................................................................... 23 3.2 Bulwark......................................................................................... 24 3.3 Support of heavy components.......................................................... 24 3.4 Deckhouses and superstructures.......................................................25

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 4

Part 5 Chapter 9 Contents

CONTENTS

4 Systems and equipment.................................................................... 26 4.1 Steering gear................................................................................. 26 4.2 Exhaust outlets...............................................................................26 4.3 Anchoring equipment...................................................................... 27 5 Stability............................................................................................. 27 5.1 Stability manual............................................................................. 27 5.2 Loading conditions.......................................................................... 27 5.3 Icing..............................................................................................27 5.4 Intact stability................................................................................ 28 6 Openings and closing appliances....................................................... 28 6.1 Weathertight doors......................................................................... 28 6.2 Freeing ports and scuppers.............................................................. 28 6.3 Windows and side scuttles for ships assigned class notation Offshore service vessel(+)..................................................................................28 Section 3 Anchor handling and towing vessels..................................................... 33 1 Introduction.......................................................................................33 1.1 Introduction................................................................................... 33 1.2 Scope............................................................................................ 33 1.3 Application..................................................................................... 33 1.4 Testing requirements....................................................................... 33 2 Hull.................................................................................................... 34 2.1 Deck structure................................................................................34 2.2 Ship’s sides and stern..................................................................... 34 3 Systems and equipment.................................................................... 35 3.1 General..........................................................................................35 3.2 Materials for equipment................................................................... 35 3.3 Anchor handling and towing winch.................................................... 36 3.4 Other equipment.............................................................................37 3.5 Marking......................................................................................... 37 4 Stability............................................................................................. 37 4.1 General requirements...................................................................... 37 Section 4 Platform supply vessels.........................................................................38 1 Introduction.......................................................................................38 1.1 Introduction................................................................................... 38 1.2 Scope............................................................................................ 38 1.3 Application..................................................................................... 38 2 Systems and equipment.................................................................... 38

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 5

Part 5 Chapter 9 Contents

3.5 Loading conditions.......................................................................... 26

2.2 Cement and dry mud systems..........................................................38 2.3 Liquid mud systems........................................................................ 39 Section 5 Standby vessels.....................................................................................40 1 Introduction.......................................................................................40 1.1 Introduction................................................................................... 40 1.2 Scope............................................................................................ 40 1.3 Application..................................................................................... 40 2 Hull.................................................................................................... 40 2.1 Ship’s sides.................................................................................... 40 2.2 Steel deckhouses and superstructures for ships assigned class notation Standby vessel(S)....................................................................42 3 Systems and equipment.................................................................... 43 3.1 Towing arrangement........................................................................43 3.2 Exhaust outlets...............................................................................43 3.3 Propulsion...................................................................................... 43 4 Fire safety and lifesaving appliances................................................. 43 4.1 Rescue zone arrangement, equipment and facilities............................. 43 4.2 Survivors spaces.............................................................................44 4.3 Safety equipment........................................................................... 44 4.4 Care of personal............................................................................. 44 5 Stability............................................................................................. 45 5.1 Intact and damage stability............................................................. 45 6 Openings and closing appliances....................................................... 45 6.1 Freeing ports..................................................................................45 6.2 Weathertight doors......................................................................... 45 6.3 Windows and side scuttles............................................................... 45 Section 6 Windfarm maintenance vessels............................................................. 46 1 Introduction.......................................................................................46 1.1 Introduction................................................................................... 46 1.2 Scope............................................................................................ 46 1.3 Application..................................................................................... 46 2 Testing requirements.........................................................................46 2.1 Work boat davits............................................................................ 46 3 Hull.................................................................................................... 47 3.1 Hull arrangement and strength......................................................... 47 4 Systems and equipment.................................................................... 47 4.1 Cranes........................................................................................... 47

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 6

Part 5 Chapter 9 Contents

2.1 General requirements for cargo handling arrangement.........................38

4.3 Work boat davits............................................................................ 47 4.4 Work boats.................................................................................... 47 5 Dynamic positioning.......................................................................... 48 5.1 Dynamic positioning system............................................................. 48 5.2 Capability plots...............................................................................48 Changes – historic................................................................................................ 50

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 7

Part 5 Chapter 9 Contents

4.2 Offshore transfer systems................................................................ 47

1 Introduction 1.1 Introduction These rules apply to vessels supporting offshore installations including towing- and anchor handling operations and rescue and standby services.

1.2 Scope The rules in this chapter give requirements to hull strength, systems and equipment, safety and availability, and stability including openings and closing appliances and the relevant procedural requirements applicable to offshore service vessels. In addition, for vessels intended for specific operations, this chapter gives additional requirements on strength, stability including openings and closing appliances and specific functions relevant for these operations.

1.3 Application The requirements in this chapter shall be regarded as supplementary to those given for the assignment of main class Pt.2, Pt.3 and Pt.4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 8

Part 5 Chapter 9 Section 1

SECTION 1 GENERAL

2.1 Ship type notations 2.1.1 Vessels built in compliance with the requirements as specified in Table 1 will be assigned the class notations as follows: Table 1 Ship type notations

Class notation

Description

Qualifier

Additional description

<none>

Offshore service vessel

Standby vessel

Ship intended for supporting offshore installations

Ship designed to carry out standby and rescue services to offshore installations

Design requirements, rule reference Sec.1 and Sec.2

+

Designed for operations in harsh weather conditions, e.g. the North Sea.

Sec.1 and Sec.2 [3]

Supply

For performing supply services to offshore installations.

Sec.1, Sec.2 and Sec.4

Anchor handling

Equipped to handle subsurface deployment and lifting of anchoring equipment, including handling of floating objects on the surface or on the sea floor.

Sec.1, Sec.2 and Sec.3

Towing

Equipped to handle towing of floating objects in open waters.

Sec.1, Sec.2 and Sec.3

AHTS

Multi-purpose offshore service vessels complying with notations Anchor handling, Towing and Supply.

Sec.1, Sec.2 Sec.3 and Sec.4

Windfarm maintenance

Equipped for maintenance and service of offshore wind farms.

Sec.1, Sec.2 and Sec.6

<none>

S

Sec.1 and Sec.5 Designed specially to operate in harsh weather conditions, e.g. the North Sea.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Sec.1 and Sec.5 [2.2]

Page 9

Part 5 Chapter 9 Section 1

2 Class notations

2.2.1 The following additional notations, as specified in Table 2, are typically applied to offshore service vessels: Table 2 Additional notations Class notation

Description

Application

Rule reference

NAUT

Requirements to bridge design, instrumentation, location of equipment and bridge procedures for enhanced safety for manoeuvring of the ship.

All ships

Pt.6 Ch.3 Sec.3

LFL

Vessel designed for carriage of liquids with low flashpoint.

All ships except Tanker for oil and Tanker for chemicals.

Pt.6 Ch.5 Sec.9

Clean

Vessel designed for controlling and limiting operational emissions and discharges.

All ships

Pt.6 Ch.7 Sec.2

DYNPOS/DPS

Vessel equipped with dynamic positioning system.

All ships

COMF

Comfort class covering requirements for noise and vibration and indoor climate.

All ships

Pt.6 Ch.8 Sec.1

OILREC

Recovered oil reception and transportation after a spill of oil in emergency situations.

All ships except Tanker for oil.

Pt.6 Ch.5 Sec.11

Fire fighter

Vessels with special fire fighting capabilities.

All ships intended for fighting fires on board ships and on offshore and onshore installations.

Ch.10 Sec.9Sec.9

SF

Compliance with the damage stability requirements of IMO Res.MSC.235(82) (Guidelines for the Design and Construction of Offshore Supply Vessels, 2006), alternatively as amended by IMO Res. MSC.335(90) (Amendments to the Guidelines for the Design and Construction of Offshore Supply Vessels, 2006).

Offshore service vessels

Pt.6 Ch.5 Sec.6

HL(ρ)

Tanks or holds strengthened for heavy liquid, where ρ denotes the maximum 3 density in t/m in any of the cargo tanks.

Pt.6 Ch.3 Sec.2 Pt.6 Ch.3 Sec.1 Pt.6 Ch.3 Sec.6

Tanker for oil Tanker for oil products Tanker for chemicals

Pt.6 Ch.1 Sec.3

Offshore service vessel

Strengthened (DK)

Decks strengthened for heavy cargo 2 applicable when deck cargo ≥1.5 t/m .

All ships

Pt.6 Ch.1 Sec.2

HELDK

Helicopter deck

All ships

Pt.6 Ch.5 Sec.5

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 10

Part 5 Chapter 9 Section 1

2.2 Additional notations

Description

Application

Rule reference

Crane

Vessel with crane(s) onboard.

All ships

Pt.6 Ch.5 Sec.3

Walk2work

Vessel with offshore gangway system.

All ships

Pt.6 Ch.5 Sec.16

2.2.2 For a full definition of all additional class notations see Pt.1 Ch.2.

3 Definitions 3.1 Terms Table 3 Definitions of terms Terms

Definition

anchor handling winch

winch used for towing and anchor handling as described in Sec.3 [3.3] The towing and anchor handling functions may be covered/fulfilled by dedicated drums on the winch.

bollard pull (BP)

the maximum continuous pull obtained at static pull test on sea trial

shark jaw

equipment for temporary securing of the inboard end of towline or rig chains

stern roller

rollers, fairleads or other equipment at the towline exit on the vessel (irrespective of location onboard), supporting the towline during lifting to avoid chafing and excessive bending, and arranged to facilitate the launch and recovery of rig anchors etc.

towing pins

equipment for leading and maintain the towline to the intended path

towing winch

winch used for towing as described in Sec.3 [3.3]

towline

rope/wire used for towing

4 Documentation 4.1 Documentation requirements 4.1.1 General For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 4.1.2 Offshore service vessel Documentation shall be submitted as required by Table 4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 11

Part 5 Chapter 9 Section 1

Class notation

Object

Documentation type

Additional description

Info

Cargo securing devices, fixed

H050 – Structural drawing

Stow racks and their supporting structures.

AP

Cargo independent tank

H050 – Structural drawing

Including design loads and reaction forces.

AP

Windows

Z030 – Arrangement plan

Information on type of glass, frames, including references to standards, and deadlights where applicable.

AP

Cargo piping system

S010 – Piping diagram (PD)

Liquid mud system

AP

Cargo piping system

S010 – Piping diagram (PD)

Cement and dry mud system

AP

Qualifier +

Qualifier Supply

Qualifiers Anchor handling and Towing Including: — towline paths showing extreme sectors and wrap on towing-equipment Z030 – Arrangement plan Anchor handling arrangement, towing winch arrangement

— towline points of attack

FI

— maximum expected BP — maximum design loads for each component — emergency release capabilities. Z253 – Test procedure for quay and sea trial

Bollard pull

AP, L

Z263 – Report from quay and sea trial

Winch and other equipment required by the class notation.

AP, L

Including: — RL and the expected maximum BP — hoisting capacity, rendering and braking force of the winch

C010 – Design criteria

Anchor handling winch, towing winch

FI

— release capabilities (response time and intended remaining holding force after release). C020 – Assembly or arrangement drawing

FI

C030 – Detailed drawing

AP Strength calculation of the drum with flanges, shafts with couplings, framework and brakes.

C040 – Design analysis C050 – Non-destructive testing (NDT) plan

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

FI AP

Page 12

Part 5 Chapter 9 Section 1

Table 4 Documentation requirements - Offshore service vessel

Documentation type

Additional description

Info

Including: — Maximum design load

C010 – Design criteria

Shark jaw, towing pins

C020 – Assembly or arrangement drawing

FI

C030 – Detailed drawing

Stern roller supporting structure, Shark jaw supporting structure,

FI

— Emergency release capabilities in operational and dead ship condition.

Components transmitting loads

AP

C040 – Design analysis

FI

C050 –Non-destructive testing (NDT) plan

AP

H050 – Structural drawing

Including maximum applicable design loads.

AP

Towing pin supporting structure Anchor handling supporting structure, Towing winch supporting structure

Including: H050 – Structural drawing

— The maximum forces acting on the winches (see Sec.3 [2.1])

AP

— Foot print loads.

Qualifier Windfarm maintenance Position keeping systems

Z201 – Position keeping capability plot

AP Safe working load, heel/trim if applicable, dynamic factor if above 1.5.

C010 – Design criteria

FI

C020 – Assembly or arrangement drawing Work boat davit winch, Work boat davit

FI

C030 – Detailed drawing

Components transmitting loads

AP

C040 – Design analysis

FI

Z161 – Operation manual

FI

Z162 – Installation manual

FI

Z163 – Maintenance manual

FI

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 13

Part 5 Chapter 9 Section 1

Object

Table 5 Documentation requirements - Standby vessel Object

Stability

Rescue and recovery arrangements Safety, general

Documentation type

Additional description

Info

B030 - Internal watertight integrity plan

FI

B070 – Preliminary damage stability calculation

AP

B130 – Final damage stability calculation

AP

Z030 – Arrangement plan

Rescue zones including contingency equipment, and accommodation, furnishings and medical equipment for rescued persons and spaces for survivors.

AP

Z090 – Equipment list

Contingency equipment for standby vessel.

AP

Including: — towline paths showing extreme sectors and wrap on towing-equipment Towing arrangement

Z030 – Arrangement plan

FI

— towline points of attack — maximum expected BP — maximum design loads for each component — emergency release capabilities.

Towing hook supporting structure, Towing winch supporting structure

H050 – Structural drawing

Maximum braking force of winch and breaking strength of the towline (if applicable).

AP

Towing hook

C030 – Detailed drawing

Including emergency release mechanism.

AP

Z030 – Arrangement plan

Including type of glass, frames, references to standards, and deadlights where applicable.

AP

Qualifier (S) Windows and side scuttles

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 14

Part 5 Chapter 9 Section 1

4.1.3 Standby vessel Documentation shall be submitted as required by Table 5.

5.1 Certification requirements 5.1.1 Supply Products shall be certified as required by Table 6. Table 6 Certification requirements - Supply Certificate type

Issued by

Cargo pumps

PC

Society

Pumps for transfer of liquid mud, fuel oil and base oil.

Cargo system valves

PC

Society

Manufacturer’s certificate may be accepted subject to approval by the Society.

Object

Certification standard*

Additional description

Electrical equipment

PC

Society

Electrical equipment (motors, frequency converters, switchgear and control gear) defined as important equipment (see Pt.4 Ch.8 Sec.1 [2.3.2]) shall be delivered with the Society’s product certificate.

Cement and dry mud tanks

PC

Society

Only applicable for independent pressure vessels, see Pt.4 Ch.7.

* Unless otherwise specified the certification standard is the rules. Guidance note: Other pumps in the cargo systems, including hydraulic power systems, need not to be delivered with the Society's certificate. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 15

Part 5 Chapter 9 Section 1

5 Certification

Part 5 Chapter 9 Section 1

5.1.2 Anchor handling and towing Products shall be certified as required by Table 7. Table 7 Certification requirements - Anchor handling and Towing Object

Certificate type

Issued by

PC

Society

MC

Society

PC

Manufacturer

Certification standard*

Additional description

Anchor handling/towing winch Towing hook Shark jaw Towing pins Shark jaw and towing pins with attachment Winch drum and flanges Shafts for drum Brake components Couplings Winch framework Gear shaft and wheels

Electrical equipment

PC

Electrical equipment (motors, frequency converters, switchgear and control gear) defined as important equipment (see Pt.4 Ch.8 Sec.1 [2.3.2]) shall be delivered with the Society’s product certificate.

Society

* Unless otherwise specified the certification standard is the rules.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 16

Table 8 Certification requirements - Standby vessel Object Loose gear of towing equipment

Certificate type

Issued by

PC

Manufacturer

Certification standard*

Additional description Including shackles, rings, wire and rope.

* Unless otherwise specified the certification standard is the rules.

5.1.4 Windfarm maintenance Products shall be certified as required by Table 9. Table 9 Certification requirements - Windfarm maintenance Object

Work boat davits

Winch for work boat davit Work boat

Certificate type

Issued by

PC

Society

MC

Society

PC

Society

MC

Society

PC

Society

Certification standard*

Additional description

DNVGL-ST-0342 Craft

* Unless otherwise specified the certification standard is the rules.

5.1.5 For a definition of the certificate types see Pt.1 Ch.3 Sec.5.

6 Testing 6.1 Testing during newbuilding 6.1.1 Testing requirements for class notations Anchor handling and Towing are given in Sec.3 [1.4], and for Windfarm maintenance in Sec.6 [2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 17

Part 5 Chapter 9 Section 1

5.1.3 Standby vessel Products shall be certified as required by Table 8.

Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4.

ss

= standard frame spacing in m = 0.48 + 0.002 L = maximum 0.61 m forward of the collision bulkhead and aft of the after peak bulkhead

L90

= rule length, L, but need not be taken greater than 90 m.

1 Introduction 1.1 Introduction These rules provide requirements for vessels intended for offshore services. This includes also operations in harsh weather conditions.

1.2 Scope These rules include requirements for hull strength, systems and equipment, and stability including openings and closing appliances applicable to offshore service vessels.

1.3 Application Vessels built in compliance with the relevant requirements in Sec.1 and Sec.2 may be given the class notation Offshore service vessel. If in addition the vessel complies with the additional requirements given in [3] and relevant parts of [6], the notation may be extended to Offshore service vessel(+). Guidance note: The extended notation Offshore service vessel(+) is recommended for vessels primarily intended to operate in harsh weather conditions, e.g. the North Sea. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

If the damage stability requirements in Pt.6 Ch.5 Sec.6 are satisfied in addition to the general requirements in [5], then the additional notation SF may be given.

2 Hull 2.1 Loads 2.1.1 Design still water bending moments and shear forces The still water bending moment and shear force limits, in seagoing and in harbour/sheltered water conditions, are normally taken as the design still water bending moments and shear forces as given in Pt.3 Ch.4 Sec.4 [2.2] and Pt.3 Ch.4 Sec.4 [2.4]. This may also be applicable for ships with length L ≤ 65m after special considerations. 2.1.2 The limits calculated in [2.1.1] may have to be calculated for extreme non-homogeneous loading conditions after special consideration of tank arrangement and cargo deck loading.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 18

Part 5 Chapter 9 Section 2

SECTION 2 OFFSHORE SERVICE VESSELS

2.2 Hull local scantling 2.2.1 Yield check of plate and stiffeners General reference is given to Pt.3 Ch.6 Sec.4 and Sec.5 for prescriptive requirements to plate and stiffeners respectively. For wheel loading, reference is given to Pt.3 Ch.10 Sec.5. Additional hull local scantling requirements for offshore service vessels are given in [2.3] to [2.6].

2.3 Ship’s sides and stern 2.3.1 Longitudinal steel fenders shall be fitted on the ship’s sides at freeboard cargo deck and second deck above. The fenders shall extend not less than 0.02 L forward of the section where the deck has its full breadth. Additional steel fenders shall be arranged aslope between the longitudinal steel fenders. The steel fenders may be omitted if the side shell scantlings are increased as specified in [2.3.2]. 2.3.2 The net thickness, in mm, of side plating including bilge strake, up to second deck above freeboard deck, shall not to be less than:

The ratio b/ss shall not be taken as less than 1.0. Requirements given for side plating in Pt.3 Ch.6 Sec.4 shall be complied with as applicable. In way of fender area described in [2.3.1], steel fenders can be omitted when the side plate thickness is at least twice that required above, for a breadth not less than 0.01 L, along the level of the freeboard deck and at the second deck above. 3

2.3.3 The net section modulus, in cm , of transverse stiffeners or side longitudinals shall not in any region be less than:

where:

Z

3

= required net section modulus, in cm , as given in Pt.3 Ch.6 Sec.5 and Pt.3 Ch.6 Sec.8.

All stiffeners up to second deck above freeboard deck, and forward of 0.2 L from FPLL. up to forecastle deck, shall have end connections with brackets. 2.3.4 Non-continuous welds shall not be used in connections between stiffeners and shell plating.

2.4 Weather deck for cargo 2

2.4.1 The deck shall have scantlings based on a minimum cargo load of 1.5 t/m , in combination with 80% of the design sea pressure as specified for the main class. If the deck scantlings are based on cargo load 2 2 exceeding 1.5 t/m , the notation Strengthened(DK) may be added. The design cargo load in t/m will be 2 given in the appendix to the classification certificate. Cargo loads exceeding 4 t/m need not be combined with sea pressure. For intermediate loads the percentage of the design sea pressure to be added shall be varied linearly.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 19

Part 5 Chapter 9 Section 2

2.1.3 If the calculated bending moments and shear forces in [2.1.2] exceed the design values given in [2.1.1], the calculated values shall be applied in the hull girder scantling check.

2.4.3 In deck areas for heavy cargo units, e.g. drilling rig anchors, the deck structure shall be strengthened against the maximum expected anchor weight. 2.4.4 Air pipes, valves, smaller hatches etc. shall be located inside the stow racks, and be protected and strengthened. 2.4.5 Scantlings of flush hatch covers in the cargo deck areas shall normally be based on the same load as the adjacent deck. In case the flush hatch cover is designed for a different load then this shall be stated in the appendix to the classification certificate.

2.5 Stow racks 2.5.1 Stow racks for pipes as deck cargo shall be provided. The stow racks shall be efficiently attached and supported at deck. The scantling of the stow racks shall be designed for a transverse load taking into account a deck load of not less than FS = 6 A, in kN, acting evenly distributed on one side of the vessel. In addition, the stow racks shall withstand the deck load at an angle of heel of 30 degrees assumed to be evenly distributed on one side of the vessel, where: 2

A = total deck area between the stow racks in m . 2.5.2 Allowable stresses 2 Acceptable stresses, in N/mm , for the stow rack scantlings and respective supporting structure resulting from bending moments and shearing forces calculated for the load given above shall be according to AC-II for primary supporting members given in Pt.3 Ch.6 Sec.6 [2]. 2

In case of direct strength calculations the equivalent von Mises stress, in N/mm , shall satisfy:

2.6 Primary supporting members 2.6.1 Direct strength analysis The strength of primary structural members that form part of a grillage system, such as deck girders, side web frames, pillars, floors and girders in double bottom may be determined by using direct strength analysis, i.e. by use of beam analysis as described in [2.6.2]. Primary supporting members shall be evaluated in accordance with Pt.3 Ch.6 Sec.6. 2.6.2 Beam analysis Beam analysis will in general be accepted to evaluate bending and shear stresses in webs and flanges of grillage structure under lateral loads such as decks, double bottom and side structure under cargo or liquid pressure, e.g. sea and tank pressures. The effective plate breadth in bending of the primary strength members shall be calculated according to Pt.3 Ch.3 Sec.7 [1.3]. 2.6.3 Design load sets General reference is made in Pt.3 Ch.6 Sec.2 Table 2 where the load combinations of static and dynamic loads for tank and watertight boundary structure, external shell envelope structure e.g. bottom structure, side shell primary members and deck structure is given. Other load combinations than those given in Pt.3 Ch.6 Sec.2 Table 2, may be accepted after consideration by the Society on a case-by-case basis. In addition to the prescriptive design load sets and load combinations given in Pt.3 Ch.6 Sec.2 Table 2, the load sets and load combinations given in Table 1 shall be applied to check the primary supporting structure on offshore service vessels, if applicable.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 20

Part 5 Chapter 9 Section 2

2.4.2 The net deck plating thickness shall not be less than 7.0 mm.

DNV GL AS

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

Table 1 Design load sets for primary supporting members Load component Description

Primary supporting members

Design load set

Hull girder loads

6)

Local load

Loading condition Acceptance for Draught criteria definition of GM and kr

Load pattern

(Pdl-s + Pdl-d , Transverse deck girders, side web frames and floors

F UDL-1 + SEA-1

4)

4)

Distributed deck load on internal or external decks (adjacent Longitudinal deck tanks empty), and bottom girders/ including grillage, stringers external shell

UDL-1h + SEA-1h UDL-1h + SEA-1h UDL-1s + SEA-1s

UDL-1s + SEA-1s UDL-1s + SEA-1s

Page 21

Transverse deck girders, side web frames and floors

UDL-2 + SEA-2 UDL-2 + SEA-2

+ FU-d

5)

) - Pex

1)

N/A

(Pdl-s + Pdl-d , F

UDL-1h + SEA-1h

U-s

U-s

5) 7)

+ FU-d

) - Pex

(Pdl-s + Pdl-d , F

4)

U-s

+ FU-d

1)

Mwv-h + 2) Msw-h

) - Pex

Mwv-h + 2) Msw-h

5)

) - Pex

(Pdl-s + Pdl-d , F

4)

U-s

+ FU-d

5) 7)

(Pdl-s + Pdl-d , F

U-s

+ FU-d

4)

Mwv-h + 3) Msw-h

1)

Mwv-s + 2) Msw-s

) - Pex

Mwv-s + 2) Msw-s

4)

Mwv-s + 3) Msw-s

5)

) - Pex

(Pdl-s + Pdl-d , F

4)

U-s

+ FU-d

5)

) - Pex

(Pdl-s + Pdl-d , F

4)

U-s

+ FU-d

5) 7)

(Pdl-s + Pdl-d , F

U-s

+ FU-d

(Pdl-s ,FU-s

5)

) - Pex

5)

5)

) - Pex

1) 4)

1) 4)

(Pdl-s ,FU-s ) - Pex

T

BAL

AC-II

Normal ballast condition

T

BAL

AC-I

Normal ballast condition

N/A N/A

Part 5 Chapter 9 Section 2

DNV GL AS

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

Load component Description

Primary supporting members

Longitudinal deck and bottom girders/ grillage, stringers

Design load set

Local load

UDL-2h + SEA-2h

(Pdl-s ,FU-s ) - Pex

UDL-2s + SEA-2s

(Pdl-s ,FU-s

5)

5)

Hull girder loads

6)

) - Pex

1) 4)

Msw-h

1) 4)

Msw-s

Loading condition Acceptance for Draught criteria definition of GM and kr

1)

The EDW giving the highest sea pressure with corresponding distributed or concentrated loads to be applied.

2)

The EDW giving the highest pressure with corresponding bending moment to be applied.

3)

The EDW giving the highest bending moment with corresponding pressure to be applied.

4)

P

5)

Distributed or concentrated loads only. Need not to be combined with simultaneously occurring green sea pressure.

6)

Local loads are defined in Pt.3 Ch.4 Sec.2 Table 1.

7)

The EDW giving the highest acceleration with corresponding sea pressure to be applied.

ex

Load pattern

shall be considered for external shell only.

Page 22

Part 5 Chapter 9 Section 2

2.6.5 Buckling check of plate panels based on beam analysis The normal stresses and shear stresses taken from the strength assessment in [2.6.2] are subject for buckling capacity calculation of plate panels as given in Pt.3 Ch.8 Sec.4 and the stresses shall be corrected as given in the Society's document DNVGL-CG-0128 Sec.3 [2.2.7].

3 Hull local scantling for ships assigned class notation Offshore service vessel(+) 3.1 Ship's sides and stern 3.1.1 Where subjected to heavy loads when handling anchors for offshore floating units drilling rigs, the stern shall be adequately strengthened. The net plate thickness, in mm, adjacent to the stern roller and shark jaw shall not be taken less than: t = 8 + 0.2 L The deck adjacent to the stern shall be strengthened accordingly. If a substantial sheathing is fitted on the deck, the requirement may be modified. 3.1.2 The net thickness of the side plating up to forecastle deck shall not be less than as given in [2.3.2]. 3

3.1.3 The net section modulus, in cm , of transverse stiffeners or side longitudinals up to second deck above the freeboard deck shall not be taken less than:

If steel fenders are omitted:

3

The net section modulus, in cm , of transverse stiffeners or side longitudinals shall, however, not in any region be taken less than:

where: 3 = required net section modulus, in cm , as given in Pt.3 Ch.6 Sec.5 and Pt.3 Ch.6 Sec.8 Z ℓbdg = effective bending span of stiffener, in m, as defined in Pt.3 Ch.3 Sec.7 [1.1.2] = stiffener spacing in mm, as defined in Pt.3 Ch.3 Sec.7 [1.2.1]. s

The requirement for Z1 given above refers to the ship’s sides, which have an inclination to the vertical (along the ship’s depth) less than 15°. For greater inclinations the requirement given for Zmin shall be applied. All stiffeners up to second deck above freeboard deck, and stiffeners forward of 0.2 L from F.E. up to forecastle deck, shall have end connections with brackets. 3.1.4 Non-continuous welds shall not be used in connections between stiffeners and shell plating up to second deck above the freeboard deck.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 23

Part 5 Chapter 9 Section 2

2.6.4 Allowable stresses See Pt.3 Ch.6 Sec.6 [2.2].

3

Part 5 Chapter 9 Section 2

3.1.5 In the ship sides up to second deck above freeboard deck, the gross section modulus, in cm , of primary supporting member (PSM) shall not be less than:

If steel fenders are omitted:

where:

ℓbdg

= effective bending span of primary supporting member, in m, as defined in Pt.3 Ch.3 Sec.7 [1.1.8]. 3

Additionally, the gross section modulus, in cm , of PSM’s shall not be less than:

Zmin Z

3

= 1.25 Z in cm . = required section modulus, as given in Pt.3 Ch.6 Sec.6 [2].

The PSM’s are assumed to have substantial connections at both ends.

3.2 Bulwark 3.2.1 The bulwark gross plate thickness shall not be less than 7 mm. Bulwark stays shall have a depth not less than 350 mm at deck. Stays shall be fitted on every second frame. Open rails shall have ample scantlings and efficient supports.

3.3 Support of heavy components 3.3.1 General Primary supporting members supporting deck cargo and equipment, foundations for separate cargo tanks, as well as supports of other heavy components, shall have scantlings based on the supported mass, forces due to the ship motions and reaction forces at supports of deck machinery. 3.3.2 Strength analysis of primary supporting members Strength analysis of primary supporting members may follow the principles given in [2.6]. 3.3.3 Pressure due to distributed deck load 2 The total pressure Pdl, in kN/m , for the static plus dynamic (S+D) design load scenarios applied for strength analysis of primary supporting members shall be in accordance with Pt.3 Ch.4 Sec.5 [2.3.1]. 2

For vessels with L < 100 m, the total pressure Pdl, in kN/m , for the static plus dynamic (S+D) design load scenarios applied for strength analysis of primary supporting members may be based on the simplified calculation as follows: — aft of 0.2 L from A.E. and forward of 0.2 L from F.E: — amidships within 0.4 L: — between specified regions, Pdl, shall be varied linearly.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 24

q = specified distributed deck load, in t/m2. 3.3.4 Concentrated forces due to unit load The force FU, in kN, due to the loads described in [3.3.1] for the static plus dynamic (S+D) design load scenarios shall be in accordance with Pt.3 Ch.4 Sec.5 [2.3.2]. 3.3.5 Allowable stresses 2 Acceptable stresses, in N/mm , for the supporting structure resulting from bending moments and shearing forces calculated for the load given above, shall be according to AC-I for primary supporting members given in Pt.3 Ch.6 Sec.6 [2.1] or Pt.3 Ch.6 Sec.6 [2.2], depending on calculation method used. 2

In case of direct strength calculations the equivalent von Mises stress, in N/mm , shall satisfy:

3.4 Deckhouses and superstructures 3

3.4.1 The net section modulus, in cm , of stiffeners and beams not contributing to longitudinal strength shall not be taken less than:

where:

P

= design pressure in kN/m

2

= PD for exposed decks max(PSI ; PW ) for exposed superstructure side P

A

for exposed end bulkheads and deckhouse boundaries 2

= minimum 10 kN/m for weather decks 2

= minimum 5 kN/m for top of the wheelhouse 2

= 8 kN/m for accommodation decks, aft of 0.2 L from A.E. and forward of 0.2 L from F.E. 2

6.5 kN/m elsewhere

2

PD

= design sea pressure, in kN/m , as given in Pt.3 Ch.4 Sec.5 [2] and Pt.3 Ch.4 Sec.5 [3], as applicable

PSI PW PA

= design sea pressure, in kN/m , for superstructure side as given in Pt.3 Ch.4 Sec.5 [3]

fbdg

= bending moment factor as defined in Pt.3 Ch.6 Sec.6 Table 1. For stiffeners with end fixity deviating from the ones included in Table 1, with complex load pattern, or being part of a grillage, the requirement in Pt.3 Ch.6 Sec.5 [1.2] applies

fu Cs

= Factor for unsymmetrical profiles, as given in Pt.3 Ch.6 Sec.5 [1.1.2]

2

2

= wave pressure, in kN/m , for superstructure side as given in Pt.3 Ch.4 Sec.5 [1.3] 2

= design sea pressure, in kN/m , for end bulkheads of superstructure and deckhouse boundaries as given in Pt.3 Ch.4 Sec.5 [3]

= permissible bending stress coefficient, taken as: C

s

= 0.75 for acceptance criteria set AC-II.

3.4.2 Stiffeners shall have effective end connections, i.e. with brackets or welded webs. Stiffeners on lower front bulkhead on weather deck forward shall have brackets at the lower ends.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 25

Part 5 Chapter 9 Section 2

where:

where:

t0

= 4.5 mm for front bulkheads and weather deck forward of the lowest tier of the front bulkhead = 3.5 mm for sides and aft end bulkheads and weather decks elsewhere = 3.0 mm for superstructure and deckhouse decks (in way of accommodation)

c

= coefficient taken as:

3.5 Loading conditions 3.5.1 The following loading conditions shall be presented: — vessel in fully loaded departure condition with cargo distributed below deck and with deck cargo specified by position and weight, with full stores and fuel, corresponding to the worst service condition in which all stability criteria are met — vessel in fully loaded arrival condition with cargo as specified, but with 10% stores and fuel — vessel in ballast departure condition, without cargo but with full stores and fuel — vessel in ballast arrival condition, without cargo but with 10% stores and fuel — vessel in the worst anticipated operating condition — if the vessel is equipped with towing gear, vessel in a typical condition ready for towing. 3.5.2 Assumptions for calculating loading conditions: — if a vessel is fitted with cargo tanks, the fully loaded conditions as described in [3.5.1] shall be modified, assuming first the cargo tanks full and then the cargo tanks empty — in all cases when deck cargo is carried a realistic stowage weight shall be assumed and stated in the stability information, including the height of the cargo and its centre of gravity — where pipes are carried on deck, a quantity of trapped water equal to a certain percentage of the net volume of the pipe deck cargo shall be assumed in and around the pipes. The net volume shall be taken as the internal volume of the pipes plus the volume between the pipes. This percentage shall be 30 if the freeboard amidships is equal to or less than 0.015 LLL and 10 if the freeboard amidships is equal to or greater than 0.03 LLL. For intermediate values of the freeboard amidships the percentage may be obtained by linear interpolation.

4 Systems and equipment 4.1 Steering gear The steering gear shall be capable of bringing the rudder from 35° on one side to 30° on the other side in 20 s, when the vessel is running ahead at maximum service speed.

4.2 Exhaust outlets Exhaust outlets from diesel engines shall have spark arrestors.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 26

Part 5 Chapter 9 Section 2

3.4.3 The net plate thickness, in mm, in superstructures and deckhouses shall not be less than:

For vessels without means for dynamic positioning, but intended for anchoring close to offshore installations/ fields, safety precautions shall be considered. Guidance note: Safety precautions may consist of increasing the diameter and length of the chain cables above the minimum class requirements given in Pt.3 Ch.11 Sec.3. In such case, for operation in the North Sea or areas with similar environmental conditions, it is recommended to have the diameter of chain cables based on an equipment letter at least two steps higher than the corresponding vessel's equipment number and length of the chain cables 85% greater than the table value corresponding to the increased diameter. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5 Stability 5.1 Stability manual 5.1.1 The requirements given in this sub-section are applicable to vessels with a freeboard length LLL of 24 m and above. 5.1.2 The stability manual shall contain the following information: — — — — — — — — — —

report on inclining test and determination of light ship data capacities and centres of gravity of all tanks and spaces intended for cargo and consumables free surface particulars for all tanks information on types, weights, centres of gravity and distribution of deck cargoes that can be carried within the limits as set out in Pt.3 Ch.15 Sec.1 [4]. Possible restrictions, such as plugging of pipes, shall be clearly stated where applicable, instructions related to the vessel when towing shall be included hydrostatic data cross curves of stability loading conditions including righting lever curves and calculation of metacentric height GM including free surface corrections curves for limiting VCG (centre of gravity above keel) or GM values for intact conditions and a curve showing the permissible area of operation stillwater bending moment and shear force limit curves.

5.2 Loading conditions For loading conditions see [3.5].

5.3 Icing 5.3.1 If the vessel is intended to operate in zones where icing is expected, this shall be included in the calculation of the stability. The vessel shall in any service condition satisfy the stability criteria set out in Pt.3 Ch.15 Sec.1 including the additional weight imposed by the ice. Weight distribution shall be taken as at 2 least 30 kg/m for exposed weather decks, passageways and fronts of superstructures and deckhouses, and 2 at least 7.5 kg/m for projected lateral planes on both sides of the vessel above the waterline. The weight distribution of ice on un-composite structures such as railings, rigging, posts and equipment shall be included by increasing the total area for the projected lateral plane of the vessel's sides by 5%. The static moment of this area shall be increased by 10%.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 27

Part 5 Chapter 9 Section 2

4.3 Anchoring equipment

5.4.1 The freeboard at the stern in the upright condition shall not be less than 0.005 LLL in any loading condition. 5.4.2 In addition to the stability criteria for main class the vessel shall comply with the requirements in Ch.10 Sec.11 [5.1] in all towing conditions.

6 Openings and closing appliances 6.1 Weathertight doors 6.1.1 Where necessary, an arrangement for protecting the doors against deck cargo shall be provided. 6.1.2 For scuttles or windows fitted in weathertight doors, they shall comply with Pt.3 Ch.12 Sec.6. 6.1.3 For ships assigned the class notation Offshore service vessel(+) the arrangements and sill heights of weathertight doors are in general to comply with Pt.3 Ch.12 Sec.6. Unprotected doors in exposed positions on a weather deck for cargo shall be made of steel. 6.1.4 For ships assigned the class notation Offshore service vessel(+), the doors located in exposed positions in sides and front bulkheads, the requirements to sill heights apply one deck higher than given by Pt.3 Ch.6 Sec.6. 6.1.5 For ships assigned the class notation Offshore service vessel(+), doorways to the engine room and other compartments below the weather deck are, as far as is practicable, to be located at a deck above the weather deck. Alternatively, two weathertight doors in series may be accepted. 6.1.6 For ships assigned the class notation Offshore service vessel(+) scuttles or windows fitted in weathertight doors shall comply with [6.3].

6.2 Freeing ports and scuppers The area of the freeing ports in the side bulwarks on the cargo deck is at least to meet the requirements of Pt.3 Ch.12 Sec.10. The disposition of the freeing ports shall be carefully considered to ensure the most effective drainage of water trapped in pipe deck cargoes and in recesses at the after end of the forecastle. In such recesses appropriate scuppers with discharge pipes led overboard may be required. If an emergency exit is located in a recess, freeing ports should be located nearby.

6.3 Windows and side scuttles for ships assigned class notation Offshore service vessel(+) 6.3.1 Typical arrangements complying with the requirements given below are shown in Figure 2 and Figure rd 3. Side scuttles will normally not be accepted in the ship sides below 3 tier forward of 0.1 LLL from forward perpendicular.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 28

Part 5 Chapter 9 Section 2

5.4 Intact stability

rd

Side scuttles below 3

tier forward of 0.1 LLL from forward perpendicular may be accepted upon special consideration with respect

to strength and position. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.3.2 In the after end bulkhead of deckhouses and superstructures, in sides of deckhouses and of superstructures that are not part of the shell plating, windows will be accepted in second tier and higher, above the freeboard deck. In front bulkheads of deckhouses and superstructures, windows will be accepted in third tier and higher, above the freeboard deck. In the first tier of the front bulkhead above the weather deck (forecastle deck) only side scuttles will be accepted. 6.3.3 Hinged deadlights shall be fitted to: — side scuttles in the vessel's hull, i.e. shell plating — windows and side scuttles in the sides of deckhouses and superstructures up to and including the third tier above the freeboard deck — all windows and side scuttles in front bulkheads of superstructures and deckhouses — windows and side scuttles in the after end of bulkheads of superstructures and deckhouses, casings and companionways in the first and second tier above the freeboard deck — windows and side scuttles in all bulkheads of the first tier on the weather deck. 6.3.4 Deadlights fitted in the side of third tier may be portable if they are stored near by For tier four and above, unless it is the first tier above the forward weather deck, the deadlights may be portable if they are stored nearby. In the second tier above the freeboard deck and higher, deadlights on windows may be arranged externally, provided there is easy and safe access for closing. Other deadlights shall be internally hinged. 6.3.5 Deadlights shall be available for each type of window sited on the front of a wheelhouse that is located on the forward part of the vessel, unless the wheelhouse is located on fifth tier (or above) and is at least two decks above the forward weather deck. For externally fitted deadlights an arrangement for easy and safe access shall be provided (e.g. gangway with railing). The deadlights of portable type shall be stowed adjacent to the window for quick mounting. For the wheelhouse front windows, at least two deadlights shall have means for providing a clear view. 6.3.6 The strength of side scuttles with internally hinged deadlights and toughened glass panes shall comply with International Standard ISO 1751 as follows: Type A (heavy):

In the hull, in the sides of superstructures and in the front of superstructures and deckhouses (weather deck tier).

Type B (medium):

In the after end of superstructures and in the sides and ends of deckhouses (except front in weather deck tier).

6.3.7 Windows shall have toughened safety glass panes of thickness, in mm, not less than as given below:

where:

β = factor obtained from the Figure 1 S = safety factor obtained from the Table 2 b = smaller dimension of the glass pane, in mm

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 29

Part 5 Chapter 9 Section 2

Guidance note:

Part 5 Chapter 9 Section 2

P = local sea pressure as given in [3.4.1], in kN/m2.

Figure 1 Curve for factor β based on window size ratio Furthermore, the thickness of windows should not be taken less than 10 mm. When laminated glass panes are used, equivalent thickness according to formula given in Pt.3 Ch.12 Sec.6 [4.1.3] shall be applied.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 30

nd

rd

th

Window and tier

2

Front or side

100

100

150

Aft

100

150

200

3

4

and above

6.3.8 Windows of design not in accordance with recognised international standards shall be approved by the Society on a case-by-case basis. Drawings showing details of the frame design, its fixation and material specification shall be submitted for approval. 6.3.9 For large windows with the lower edge positioned at or less than 900 mm above the deck, provision of handrails at a level approximately 1 m above the deck shall be considered when applicable.

Figure 2 Side scuttles and windows in supply vessel with complete superstructure and uppermost forecastle

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 31

Part 5 Chapter 9 Section 2

Table 2 Safety factor (S)

Part 5 Chapter 9 Section 2 Figure 3 Side scuttles and windows in supply vessel with forecastle only

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 32

Part 5 Chapter 9 Section 3

SECTION 3 ANCHOR HANDLING AND TOWING VESSELS Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction The requirements in this section apply to vessels intended for anchor handling and towing operations offshore. Anchor handling operations implies towing of floating objects in open waters and objects on sea bed in addition to subsurface deployment and lifting of anchoring equipment. Towing operations implies towing of floating objects in open waters.

1.2 Scope The following is covered by this section: — design and testing requirements to towing and anchor handling equipment — hull arrangement and supporting structure — stability and watertight integrity. Basic requirements for anchor handling and towing vessels are given in Sec.1 and Sec.2.

1.3 Application Vessels with class notation Offshore service vessel intended for anchor handling operations built in compliance with the requirements in this section may be given the class notation qualifier Anchor handling. Vessels with class notation Offshore service vessel intended for towing operations built in compliance with relevant requirements in this section may be given the class notation qualifier Towing.

1.4 Testing requirements 1.4.1 The winch and other equipment made mandatory in this section shall be function tested according to approved procedure in order to verify: — the ability for the arrangement and equipment to operate within the specified limitations, towline paths, towline sectors etc. specified by the arrangement drawing — the correct function of the normal operation modes — the correct function of the emergency operation modes, including emergency release and dead ship operations. 1.4.2 The winch shall be load tested during hoisting, braking, and pay out. Design loads to be applied. However, a maximum load equal to BP may be accepted if the winch is not of novel design or complex structure. 1.4.3 The BP testing shall comply with applicable requirements in Ch.10 Sec.11 [1.5].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 33

2.1 Deck structure 2.1.1 Scantlings of foundations and supports of towing pins shall be based on two (2) times the specified maximum static working load specified by the designer. 2.1.2 Scantlings of foundations and supports of winches intended for towing functions shall be based on minimum 2.2 times the maximum BP of the vessel. 2.1.3 Scantlings of foundations and supports of winches intended for anchor handling functions shall be based on 1.5 times the specified maximum hoisting capacity or the maximum brake holding capacity of the winch whichever is the greater. 2.1.4 Scantlings of foundations and supports of stern roller shall be based on two (2) times the maximum static working load as specified by the designer or two (2) times the specified maximum hoisting capacity of the anchor handling winch whichever is the greater. 2.1.5 Scantlings of foundations and supports of shark jaws shall be based on two (2) times the maximum static working load as specified by the designer. 2

2.1.6 Acceptable stresses, in N/mm , for the scantlings of the supporting structure resulting from bending moment M, in kNm, and shear force Q, in kN, calculated for the load given above are: 2

σb

= bending stress, in N/mm , taken as:

τ

= average shear stress, in N/mm , taken as:

Z Ashr

= net section modulus, in cm

2

3

2

= net shear area, in cm . 2

In case of direct strength calculations the equivalent von Mises stress, in N/mm , shall satisfy:

2.2 Ship’s sides and stern 2.2.1 Where subjected to heavy loads when handling anchors, the stern and the flat part of bottom in way of stern shall be adequately strengthened. The net plate thickness shall not be less than twice the basic requirement stated in Sec.2 [2.3.2]. The deck adjacent to the stern shall be strengthened accordingly. If a substantial sheathing is fitted on the deck, the requirement may be modified.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 34

Part 5 Chapter 9 Section 3

2 Hull

3.1 General 3.1.1 The equipment shall meet the requirements in this section. Alternatively, equipment complying with a recognized standard may be accepted upon special considerations provided such standard gives a reasonable equivalence to the requirements of this section and fulfils the intention. 3.1.2 Arrangement drawing for anchor handling and towing with the content listed under documentation requirement in this section shall be posted on the bridge. 3.1.3 Structural elements, e.g. cargo rails, bulwarks, etc., that may support the towline during normal operation, shall have a radius of bend sufficient to avoid damage to the towline. 3.1.4 The arrangement shall be such that the heeling moment arising when the towline is running in the athwart ships direction, will be as small as possible. 3.1.5 Vessel with class notation qualifier Anchor handling shall be fitted with the following items: — — — —

anchor handling winch shark jaw towing pins stern roller.

3.1.6 Vessel with class notation qualifier Towing shall be fitted with the following items: — towing winch or towing hook. 3.1.7 If a vessel with qualifier Towing is fitted with towing pins and/or shark jaws, these shall be certified as specified in Sec.1 Table 7. 3.1.8 The arrangement shall be such that the towline is led to the winch drum in a controlled manner under all foreseeable conditions (directions of the towline) and provide proper spooling on drum.

3.2 Materials for equipment 3.2.1 Shark jaw and towing pins with attachment shall be made of rolled, forged or cast steel in accordance with Pt.2 Ch.2. 3.2.2 For anchor handling and towing winch materials shall comply with relevant specifications given in Pt.2. 2

3.2.3 For forged and cast steel with minimum specified tensile strength, Rm above 650 N/mm , specifications of chemical composition and mechanical properties shall be submitted for approval for the equipment in question. 3.2.4 Plate material in welded parts shall be of the grades as given in Pt.3 Ch.11 Sec.1 Table 10. 3.2.5 When ReH is greater than 80% of Rm, the following value shall be used as ReH in calculations for structural strength as given in [3.3]:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 35

Part 5 Chapter 9 Section 3

3 Systems and equipment

3.3 Anchor handling and towing winch 3.3.1 Control system The control stands shall provide a safe and logical interface to the operator with operating levers returning to stop position when released and in addition provide a clear view to the drums. The anchor handling winch shall be capable of controlled operation during lowering and hoisting of anchors both submerged and over the stern roller. 3.3.2 Monitoring system Device for measuring tension in tow rope should be fitted. 3.3.3 Emergency release The winch shall be designed to allow drum release in an emergency, and in all operational modes. The release capabilities shall be as specified on arrangement drawing as required in [3.1.2]. The action to release the drum shall be from a position at the bridge with full view and control of the operation. Identical means of equipment for the release operation to be used on all release stations. After an emergency release the winch brake shall be in normal function without delay. It shall always be possible to carry out the emergency release sequence (emergency release and/or application of brake), even during a black-out. Control handles, buttons etc. for emergency release shall be protected against unintentional operation. 3.3.4 Structural strength of winch for anchor handling function Winch for anchor handling function shall be capable of withstanding the maximum forces from hoisting, rendering and braking, including dynamic effects, without exceeding the following stress levels: — hoisting including dynamic effect at relevant layer: 0.67 ReH — braking at relevant layer as specified in [3.3.10]: 0.67 ReH — rendering load/load in towline when drum starts to rotate in the opposite direction of the applied driving torque: 0.85 ReH. Buckling and fatigue shall be considered according to a recognized standard or code of practice. 3.3.5 Structural strength for winch for towing function The design and scantlings shall be capable of withstanding the winch holding capacity as given in Ch.10 Sec.11 [3.3] without permanent deformations at relevant layer. Buckling and fatigue shall be considered according to a recognized standard or code of practice. 3.3.6 Winch intended for both functions shall meet requirements both in [3.3.4] and [3.3.5]. 3.3.7 Drums The drum design shall be carried out with due consideration to the relevant operations. The drum diameter for steel wire rope should not be less than 14 times the maximum intended diameter of the rope. However, for all rope types, the rope bending specified by the rope manufacturer should not be exceeded. 3.3.8 Towline attachment The end attachment of the towline to the winch barrel shall be of limited strength making a weak link in case the towline has to be run out. At least 3 dead turns of rope are assumed on the drum under normal operation to provide proper attachment.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 36

Part 5 Chapter 9 Section 3

3.2.6 Fabrication of items in [3.4.1] shall be in accordance with the Society's document DNVGL-ST-0378 Offshore and platform lifting appliances or a standard recognised by the Society.

3.3.10 Brake on drum intended for anchor handling The brake shall normally act directly on drum. It shall be capable of holding at least 1.25 times the maximum torque created from towline pull including dynamic effect. In addition, the brake shall be capable of stopping the rotation of the drum from its maximum speed. The holding load of the winch shall not be affected by failure in the power supply and the brake shall be actuated at power failure if the load is not controlled by the winch motors or similar. Means shall however be provided for overriding such systems at any time. 3.3.11 Brake on drums intended for both functions shall meet the requirements in [3.3.9] and [3.3.10].

3.4 Other equipment 3.4.1 The shark jaw shall be capable of sustaining the load defined on the arrangement drawing given in [3.1.2] without exceeding a stress level of 0.67 ReH. Dynamic effect shall be included. 3.4.2 The towing pins shall withstand forces and towline sectors defined on the arrangement drawing given in [3.1.2] without exceeding a stress level of 0.67 ReH. Dynamic effect shall be included. 3.4.3 If an emergency release on shark jaw and towing pins is arranged, the capabilities shall be as specified on the arrangement drawing given in [3.1.2]. 3.4.4 When towing hook is fitted, applicable requirements in Ch.10 Sec.11 [3.5] shall be complied with.

3.5 Marking 3.5.1 Equipment shall be marked to enable them to be readily related to their specifications and manufacturer. When the Society's product certificate is required, the equipment shall be clearly marked by the Society for identification.

4 Stability 4.1 General requirements 4.1.1 For towing operations, stability shall comply with applicable requirements in Ch.10 Sec.11 [5.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 37

Part 5 Chapter 9 Section 3

3.3.9 Brake on drum intended for towing The brake shall normally act directly on drum and should be capable of holding the winch holding capacity as given in Ch.10 Sec.11 [3.3] at inner layer. It shall be arranged for manual operation or other means for activation during failure of the power supply.

1 Introduction 1.1 Introduction The requirements in this section apply to vessels designed specially for platform supply services.

1.2 Scope In addition to the basic requirements given in Sec.1 and Sec.2, the section contains additional requirements for cargo handling arrangement and certification of cement and dry mud tanks onboard platform supply vessels.

1.3 Application Vessels with class notation Offshore service vessel built in compliance with the relevant requirements in this section may be given the qualifier Supply.

2 Systems and equipment 2.1 General requirements for cargo handling arrangement 2.1.1 Systems and arrangements shall in general comply with the relevant requirements for main class given in Pt.4 Ch.6. Redundancy requirements for cargo pumps as specified in Ch.5 Sec.4 [3.1.1] and Ch.6 Sec.6 [2.2.1] are not applicable. 2.1.2 Cargo pumps shall be provided with remote shut down devices capable of being activated from a dedicated cargo control location which is manned at the time of cargo transfer. Remote shut down shall also be capable of being activated from at least one other location outside the cargo area and at a safe distance from it. 2.1.3 Segregation between cargo piping systems where cross-contamination causes safety hazards or marine pollution hazards shall be by means of spectacle flanges, spool pieces or equivalent. Valve segregation is not considered equivalent. 2.1.4 Vessels intended for transportation of liquids with flashpoint below 60°C shall comply with Pt.6 Ch.5 Sec.9. Vessels that occasionally handle, store and transport recovered oil from a spill shall comply with Pt.6 Ch.5 Sec.11.

2.2 Cement and dry mud systems 2.2.1 Cement and dry mud tanks and piping systems shall in general be separated from the engine room. Where cement and dry mud tanks are situated in way of engine room, at least the upper parts of the tanks with hatches, pipe connections and other fittings, shall be segregated from the engine room by a steel deck and bulkhead. 2.2.2 Where cement and dry cargo piping is led through the engine room, the wall gross thicknesses of the pipes shall not be less than given in Table 1. Pipe connections located in the engine room shall be welded as

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 38

Part 5 Chapter 9 Section 4

SECTION 4 PLATFORM SUPPLY VESSELS

2.2.3 Access doors between the engine room and spaces in which cement and dry mud systems are located, shall be provided with signboard stating that the doors shall be kept closed while the system is under pressure. 2.2.4 Cement and dry mud tanks shall be certified in accordance with the requirements for pressure vessels given in Pt.4 Ch.7. Table 1 Pipes for cement and dry mud. Minimum nominal wall gross thickness for steel pipes in engine room External diameter [mm]

Wall gross thickness [mm]

38 to 82.5

6.3

88.9 to 108

7.1

114.3 to 139.7

8.0

152.4 to 273

8.8

2.3 Liquid mud systems 2.3.1 Liquid mud carried onboard supply vessels shall have a flash point not lower than 60°C. 2.3.2 Means for relief of overflow shall be provided, e.g. through a non-return valve fitted in a branch connection to the air pipe. The sectional area of the overflow pipe shall be at least twice that of the filling pipe.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 39

Part 5 Chapter 9 Section 4

far as practicable. Necessary detachable connections shall be of such design that blow-out is prevented. The arrangement will be specially considered in each particular case.

Part 5 Chapter 9 Section 5

SECTION 5 STANDBY VESSELS Symbols For symbols not defined in this section, see Pt.3 Ch.1 Sec.4.

ss = standard frame spacing in m = 0.48 + 0.002 L

= maximum 0.61 m forward of collision bulkhead and aft of the after peak bulkhead.

1 Introduction 1.1 Introduction The requirements in this section apply to vessels especially designed to carry out rescue and standby services to offshore installations.

1.2 Scope This section contains requirements for hull arrangement, strength and equipment.

1.3 Application Vessels built in compliance with the requirements in [1] to [6] of this section, except [2.2], may be given the class notation Standby vessel. Guidance note: The flag administration may have requirements for the same items found in these rules. The stricter one is expected to prevail. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

If in addition the vessel complies with requirements on strengthening of the superstructure and deckhouses given in [2.2], the notation may be extended to Standby vessel(S). Guidance note: The notation Standby vessel(S) is recommended for vessels primarily to operate in harsh weather conditions, e.g. the North Sea. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2 Hull 2.1 Ship’s sides 3

2.1.1 The net section modulus of transverse stiffeners or side longitudinals, in cm , shall not in any region be taken less than:

where:

Z = net section modulus, as given in Pt.3 Ch.6 Sec.5 and Pt.3 Ch.6 Sec.8. All stiffeners up to second deck above freeboard deck, and forward of 0.2 L from F.E. up to forecastle deck, shall have end connections with brackets.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 40

In way of steel fender area along the level of the freeboard cargo deck and second deck above, the net thickness, in mm, for a breadth not less than 800 + 5 L, in mm, shall not be taken less than:

The ratio b/ss shall not be taken as less than 1.0. If steel fenders are omitted, as for instance within the rescue zone, the above minimum thickness shall be increased by 50%, for a breadth not less than 0.01L, in m, along the level of the freeboard cargo deck and the second deck above. If the vessel is not assigned with class notation Offshore service vessel, the net side plate thickness above the bilge, in mm, in way of the rescue zone, shall not be less than:

2.1.3 The net plate thickness of the exposed weather deck at the rescue zone, in mm, within at least 1.0 m from the ship side, shall not be less than: t = 6.0 + 0.02 L 2.1.4 Bulwark gross plate thickness shall not be less than 7 mm. On the main weather deck the bulwark stays shall have a depth not less than 350 mm at deck and positioned at every second frame. Open rails shall have ample scantlings and efficient supports. 2.1.5 Scantlings of foundations and supports of towing winch and towing hook shall withstand a load 0.04 PS 2 tonnes, where PS is the total power of the propulsion engines in kW. Acceptable stresses, in N/mm , in the supporting structure resulting from bending moment M, in kNm, and shear force Q, in kN, calculated for the load given above are: 2

σb

= bending stress, in N/mm , taken as:

τ

= average shear stress, in N/mm , taken as:

Z Ashr

= net section modulus, in cm

2

3

2

= net shear area, in cm . 2

In case of direct strength calculations the equivalent von Mises stress, in N/mm , shall satisfy:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 41

Part 5 Chapter 9 Section 5

2.1.2 Longitudinal steel fenders shall be fitted on the ship´s sides at freeboard cargo deck and second deck above. The steel fenders shall extend not less than 0.02 L forward of the section where the deck has its full breadth.

2.2.1 Scantling for superstructures and deckhouses 3 The net section modulus, in cm , of stiffeners and beams not contributing to longitudinal strength shall not be less than:

where:

P

= design pressure in kN/m

2

= PD for exposed decks max(PSI; PW) for exposed superstructure side PA for exposed end bulkheads and deckhouse boundaries 2

= minimum 10 kN/m for weather decks 2

= minimum 5 kN/m for top of the wheelhouse 2

= 8 kN/m for accommodation decks, aft of 0.2 L from A.E. and forward of 0.2 L from F.E. 2

6.5 kN/m elsewhere

2

PD PSI PW PA

= design sea pressure, in kN/m , as given in Pt.3 Ch.4 Sec.5 [2] and [3], as applicable

fbdg

= bending moment factor as defined in Pt.3 Ch.6 Sec.6 Table 1. For stiffeners with end fixity deviating from the ones included in Pt.3 Ch.6 Sec.6 Table 1, with complex load pattern, or being part of a grillage, the requirement in Pt.3 Ch.6 Sec.5 [1.2] applies

fu Cs

= Factor for unsymmetrical profiles, as given in Pt.3 Ch.6 Sec.5 [1.1.2]

2

= design sea pressure, in kN/m , for superstructure side as given in Pt.3 Ch.4 Sec.5 [3] 2

= wave pressure, in kN/m , for superstructure side as given in Pt.3 Ch.4 Sec.5 [1.3] 2

= design sea pressure, in kN/m , for end bulkheads of superstructure and deckhouse boundaries as given in Pt.3 Ch.4 Sec.5 [3]

= permissible bending stress coefficient, taken as: Cs = 0.75 for acceptance criteria set AC-II.

2.2.2 Stiffeners shall have effective end connections, i.e. with brackets or welded webs. Stiffeners on lower front bulkhead on weather deck forward shall have brackets at the lower ends. 2.2.3 The net plate thickness, in mm, in superstructures and deckhouses shall not be less than:

where:

t0 = 4.5 for front bulkheads and weather deck forward of the lowest tier of the front bulkhead = 3.5 for sides and aft end bulkheads and weather decks elsewhere

= 3.0 for superstructure and deckhouse decks (in way of accommodation)

c = coefficient taken as:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 42

Part 5 Chapter 9 Section 5

2.2 Steel deckhouses and superstructures for ships assigned class notation Standby vessel(S)

3.1 Towing arrangement 3.1.1 When the vessel is fitted with means for emergency towing, the towing winch and or towing hook shall satisfy the requirements given in Ch.10 Sec.11 [3.3.2], Ch.10 Sec.11 [3.5.2] and Ch.10 Sec.11 [3.7.6]. 3.1.2 For ships which are not built according to the rules for Tug, Towing, Anchor handling or AHTS notation, the towing wire and all connected parts shall have a minimum breaking load of 0.04 PS tonnes, where PS is the total power of the propulsion engines in kW. 3.1.3 All loose gear of the towing equipment, like shackles, rings, wire and ropes shall be delivered with a work's certificate.

3.2 Exhaust outlets 3.2.1 Exhaust outlets from diesel engines shall have spark arrestors.

3.3 Propulsion 3.3.1 The vessel shall be fitted with 2 propulsion systems or similar capable of moving the vessel in the forward/aft direction.

4 Fire safety and lifesaving appliances 4.1 Rescue zone arrangement, equipment and facilities 4.1.1 The vessel shall be arranged on each side with a rescue zone with minimum 8 m length. The area shall be clearly marked on the ship's side. Its location shall be sufficiently far away from the propellers and clear of any ship side discharges up to 2 m below the loaded waterline. 4.1.2 Access routes from the rescue zones to survivors' accommodation and to helicopter winch zone if provided shall have slip-resistant deck coating or wooden lining with surface treatment giving equivalent properties. 4.1.3 The ship's side in way of the rescue zone shall be free of any obstruction, like for example, fenders, and clear of any discharge pipe connections. 4.1.4 Satisfactory lighting shall be available along the rescue zone capable of providing minimum illumination level of 150 lux at the rescue zone and 50 lux at 20 m from the vessel. 4.1.5 Deck area in way of the rescue zone should preferably be free from air pipes, valves, smaller hatches etc. However, when this becomes impractical, proper arrangement shall be provided to protect against personnel injury. 4.1.6 To enable direct boarding on the deck, bulwark or railings in the rescue zone shall be easy to open or remove.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 43

Part 5 Chapter 9 Section 5

3 Systems and equipment

4.1.8 Each rescue zone shall be provided with a scrambling net made of corrosion resistant and non-slip material. 4.1.9 The vessel shall be provided with power assisted means capable of ensuring careful recovery of disabled persons from the sea. 4.1.10 A decontamination area equipped with a shower system shall be arranged for cleaning survivors and crew before entering the superstructure.

4.2 Survivors spaces 4.2.1 The vessel shall have a treatment room for casualties, a recovery room with berths, and enclosed space to accommodate survivors. These spaces shall be provided with lighting and means to control temperature and humidity suitable for the area of operation. The survivors may be accommodated in crew spaces, excluding sanitary rooms, treatment rooms, galley, wheelhouse, radio room, cabins for captain and two crew members. 2

The designed capacity of survivors shall be determined considering 0.75 m per person. This includes free floor space and floor space with loose furniture, fixed seating and/or fixed beds. Other fixed furniture, toilets and bathrooms shall be excluded. Corridors and doors giving access to the treatment room for casualties and recovery room shall be dimensioned to allow adequate transport of survivors by stretchers. 4.2.2 Sanitary facilities shall be available exclusively for the survivors. At least one installation comprising a toilet, a wash basin and shower shall be provided for each group of 50 survivors.

4.3 Safety equipment 4.3.1 The vessel shall be equipped with at least one fast rescue boat of type complying with IMO MSC/ Circ.809, arranged and maintained to be permanently ready for use under severe weather conditions. The launching arrangement shall be a SOLAS approved type. 4.3.2 The following minimum safety equipment shall be provided when the vessel has a gross tonnage less than 500: — — — — —

one line-throwing appliance with not less than four projectiles and four lines one daylight signalling lamp six lifebuoys, 4 being with a self-igniting light and buoyant line (SOLAS approved type) one SOLAS type approved immersion suit for each crew member one SOLAS type approved lifejacket for each crew member plus 25% of the number of survivors for which the vessel is intended to carry.

4.4 Care of personal 4.4.1 The treatment room shall have adequate equipment and medical supplies. 4.4.2 Treatment room equipment and medical stores shall be arranged as required by local regulations or based on recognised standards.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 44

Part 5 Chapter 9 Section 5

4.1.7 A searchlight shall be available on each side and operated from the navigation bridge. The searchlights should be able to provide an illumination level of 50 lux in clear air, within an area not less than 10 m diameter, to a distance of 250 m.

The vessel should be provided with blankets in sufficient quantity for the number of survivors for which the vessel is intended to carry. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5 Stability 5.1 Intact and damage stability 5.1.1 The vessel shall comply with intact stability requirements as given in Sec.2 [5] and damage stability requirements as given in Pt.6 Ch.5 Sec.6. Guidance note: A detailed description of stability documentation is given in the Society's document DNVGL-CG-0157 Stability documentation for approval. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6 Openings and closing appliances 6.1 Freeing ports 6.1.1 The area of the freeing ports in the side bulwarks on the cargo deck shall at least meet the requirements of Pt.3 Ch.12 Sec.10. The arrangement of the freeing ports shall be carefully considered to ensure the most effective drainage of water trapped on the weather deck.

6.2 Weathertight doors 6.2.1 The arrangement and sill heights of weathertight doors shall comply with Pt.3 Ch.12 Sec.6. Doors in exposed positions on the lowest weather deck and in lowest unprotected fronts and sides shall be of steel. 6.2.2 For doors located in exposed positions in sides and front bulkheads, the requirements to sill heights apply one deck higher than given by Pt.3 Ch.12 Sec.6. 6.2.3 Doorways to the engine room and other compartments below the weather deck shall, as far as practicable, be located at a deck above the weather deck. Alternatively, two weathertight doors in series may be accepted.

6.3 Windows and side scuttles 6.3.1 Arrangement of windows and scuttles shall comply with the requirements given in Sec.2 [6.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 45

Part 5 Chapter 9 Section 5

Guidance note:

1 Introduction 1.1 Introduction 1.1.1 The requirements in this section apply to vessels intended for maintenance of offshore wind farms. Wind farm maintenance may include: — — — —

being a mother craft for smaller craft transferring technicians to and from offshore wind turbines transferring technicians directly to the wind turbine transferring supplies to the wind turbine perform smaller lifting operations onto the wind turbine.

1.2 Scope 1.2.1 This section contains requirements to hull arrangement, strength, equipment and dynamic positioning system. Guidance note: Coastal state and/or statutory regulations may include requirements in excess of the provisions of these rules depending on the size, type, location and intended service of the unit/installation. These requirements are excluded from this section. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3 Application 1.3.1 Vessels with class notation Offshore service vessel intended for maintenance of offshore wind farms built in compliance with the requirements in this section may be given the class notation qualifier Windfarm maintenance.

2 Testing requirements 2.1 Work boat davits 2.1.1 Testing at factory and after installation on board shall be performed in line with IMO MSC. 81(70) part 2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 46

Part 5 Chapter 9 Section 6

SECTION 6 WINDFARM MAINTENANCE VESSELS

3.1 Hull arrangement and strength 3.1.1 The hull structural strength shall be as required for the main class taking into account necessary strengthening of supporting structures for equipment applied during the maintenance and service of offshore wind farms. 3.1.2 All load effects caused by deck cargo and heavy equipment shall be accounted for in the design calculations for all operational phases.

4 Systems and equipment 4.1 Cranes 4.1.1 For wind farm maintenance vessels equipped with cranes applied in wind farm maintenance operations, class notation Crane covering these cranes is mandatory. These cranes will be defined as offshore cranes.

4.2 Offshore transfer systems 4.2.1 If the vessel is equipped with an offshore transfer system to transfer technicians from the ship to the wind turbine, class notation Walk2work covering this transfer system is mandatory.

4.3 Work boat davits 4.3.1 Where fitted, work boat davits and winches shall comply with SOLAS 1974 and the LSA Code. 4.3.2 Functional and operational requirements: — — — —

no requirements to heel or trim unless specified by operator stored mechanical power not required, however lowering in dead ship condition shall be possible no requirements to hoisting or lowering speed unless specified by the flag administration if estimated dynamic factor exceed 1.5, shock damper arrangement is required.

4.3.3 In addition to strength requirements given in the above regulations, fatigue check according to a recognised standard shall be performed.

4.4 Work boats 4.4.1 All work boats fitted onboard shall be certified by the Society according to DNVGL-ST-0342 Craft 4.4.2 The ship side in way of the work boats shall be equipped with fenders to reduce the impact during launch and recovery of the craft.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 47

Part 5 Chapter 9 Section 6

3 Hull

5.1 Dynamic positioning system 5.1.1 The vessel shall, as a minimum, have class notation DYNPOS(AUTR), DPS(2) or DYNPOS(E).

5.2 Capability plots 5.2.1 The position keeping ability of the vessel shall be calculated and presented in form of capability plots as outlined in these rules. The capability plots shall be kept onboard. Guidance note: It is recommended that DNV GL standard DNVGL-ST-0111 Assessment of station keeping capability of dynamic positioning vessels is used as a guideline for making capability plots. The correlation between wind speed and waves height and period provided in this standard can also be used for other current speeds than the ones specified by the standard. Linear interpolation between points is acceptable. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.2 The capability plots shall be produced in polar form, as a static analysis with coincident forces of wind, waves, and current. In the analysis the vessel shall maintain fixed position and heading, and shall be exposed to forces from a fixed current speed corresponding to the intended location of operation but in any case not less than 1.5 m/s with correlating wind and waves. The fixed current speed applied shall be specified in the appendix to classification certificate. 5.2.3 Thus there shall at the same time be a balance of forces and a balance of moments, i.e. including all moments generated by the thrusters, and those caused by environmental forces. 5.2.4 The limiting wind speed where the current, wind and wave forces equals the maximum available thruster forces shall be plotted at least every 15° around the vessel. Linear interpolation between points is acceptable. 5.2.5 The environmental forces caused by wind, waves, and current shall be calculated by recognised methods. Guidance note: Alternatively, environmental forces established by model testing may be used. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.6 The capability plots shall be based upon available power and the thrust output that is under control, in the most efficient control mode. 5.2.7 A minimum of four plots is required: — — — —

Case 1 shall represent optimal use of all thrusters Case 2 shall represent minimum effect of single-thruster failure Case 3 shall represent the maximum effect of single-thruster failure Case 4 shall represent the worst case failure modes. There shall be one plot for failure of each redundancy group or an amalgamated plot shall be provided with the lowest result for each heading across all the redundancy groups.

All plots shall be produced on the same scale.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 48

Part 5 Chapter 9 Section 6

5 Dynamic positioning

Part 5 Chapter 9 Section 6

Guidance note: It is recommended that the wind speed scale is 15 mm = 10 m/s and with range 0 to 50 m/s. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note: An amalgamated plot shall represent the vessel capability in all directions and can therefore in many cases represent several different failure conditions, as the WCSF typically will be heading dependent. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 49

January 2017 edition

Amendments July 2017 • Sec.1 General — Sec.1 Table 1: Rule reference to Sec.4 for AHTS has been added.

• Sec.3 Anchor handling and towing vessels — Sec.3 [3.1.7]: Clarification of certification requirement of towing pin and shark jaws in Pt.5 Ch.9 Sec. 3 [3.1.7] has been added.

Main changes January 2017, entering into force 1 July 2017 • Sec.2 Offshore service vessels 3

3

— Sec.2 [5.3.1]: Amended ice load on side structures from 15 kg/m to 7.5 kg/m to be in line with IMO requirements and initial intention/current practice.

• Sec.3 Anchor handling and towing vessels — Sec.3: Removed requirement to local operation of deck winches.

July 2016 edition

Main changes July 2016, entering into force as from date of publication • Sec.2 Offshore service vessels — Sec.2 [2.3.3]: Amended the application of end brackets for transverse and side longitudinal stiffeners. — Sec.2 [3.4.1]: Updated rule reference to Pt.3 Ch.4 Sec.5 [1.3] for wave pressure on exposed superstructure.

• Sec.5 Standby vessels — Sec.5 [2.1.1]: Amended the application of end brackets for transverse and side longitudinal stiffeners. — Sec.5 [2.1.2]: The plate width of the increased fender plate thickness has been amended in order to get in line with current industry practice. — Sec.5 [2.1.3]: The minimum thickness requirement on exposed weather deck at the rescue zone has been corrected after adjustments made to the general minimum thickness requirement in Pt.3 for weather decks. The minimum thickness requirement will be in line with current industry practice. — Sec.5 [2.2.1] Updated rule reference to Pt.3 Ch.4 Sec.5 [1.3] for wave pressure on exposed superstructure.

October 2015 edition

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 50

Part 5 Chapter 9 Changes – historic

CHANGES – HISTORIC

Part 5 Chapter 9 Changes – historic

This is a new document. The rules enter into force 1 January 2016.

Amendments January 2016 • Sec.2 Offshore service vessels — Table 1: Amended the reference notes for acceptance criteria AC-I.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.9. Edition January 2018 Offshore service vessels

DNV GL AS

Page 51

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition January 2018

Part 5 Ship types Chapter 10 Vessels for special operations

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

Part 5 Chapter 10 Changes - current

CHANGES – CURRENT This document supersedes the July 2017 edition of DNVGL-RU-SHIP Pt.5 Ch.10. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018. Topic New ship type notation Tanker for potable water

Reference Sec.16

Description For vessels intended to carry potable water in bulk.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 3

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................. 14 1 Introduction.......................................................................................14 1.1 Introduction................................................................................... 14 1.2 Scope............................................................................................ 14 1.3 Application..................................................................................... 14 2 Class notations.................................................................................. 14 2.1 Ship type notations.........................................................................14 2.2 Additional notations........................................................................ 17 3 Definitions..........................................................................................19 3.1 Terms............................................................................................ 19 4 Documentation...................................................................................20 4.1 Documentation requirements............................................................20 5 Certification....................................................................................... 32 5.1 Certification requirements................................................................ 32 6 Testing............................................................................................... 36 6.1 Testing during newbuilding...............................................................36 Section 2 Crane vessel.......................................................................................... 37 1 Introduction.......................................................................................37 1.1 Introduction................................................................................... 37 1.2 Scope............................................................................................ 37 1.3 Application..................................................................................... 37 1.4 Testing requirements....................................................................... 37 2 Hull.................................................................................................... 37 2.1 General..........................................................................................37 3 Systems and equipment.................................................................... 38 3.1 Crane with substructure.................................................................. 38 4 Stability............................................................................................. 38 4.1 Application..................................................................................... 38 4.2 General intact stability criteria for heavy lift operations........................ 39 4.3 Intact stability for sudden loss of hook load....................................... 39 4.4 Alternative intact stability criteria during heavy crane lift..................... 41 4.5 Alternative damage stability criteria during heavy crane lift.................. 42 Section 3 Cable laying vessel................................................................................ 44

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 4

Part 5 Chapter 10 Contents

CONTENTS

1.1 Introduction................................................................................... 44 1.2 Scope............................................................................................ 44 1.3 Application..................................................................................... 44 2 Hull.................................................................................................... 44 2.1 Hull structural strength....................................................................44 2.2 Special hull configuration................................................................. 44 3 Equipment..........................................................................................44 3.1 Equipment for mooring and anchoring............................................... 44 Section 4 Pipe laying vessel..................................................................................45 1 Introduction.......................................................................................45 1.1 Introduction................................................................................... 45 1.2 Scope............................................................................................ 45 1.3 Application..................................................................................... 45 2 Hull.................................................................................................... 45 2.1 Hull structural strength....................................................................45 2.2 Special hull configuration................................................................. 45 3 Equipment..........................................................................................45 3.1 Equipment for mooring and anchoring............................................... 45 Section 5 Semi-submersible heavy transport vessel............................................. 46 1 Introduction.......................................................................................46 1.1 Introduction................................................................................... 46 1.2 Scope............................................................................................ 46 1.3 Application..................................................................................... 46 1.4 Testing requirements....................................................................... 46 2 Hull.................................................................................................... 46 2.1 Hull girder strength.........................................................................46 2.2 Local strength................................................................................ 47 2.3 Integrated high-pressure tanks.........................................................47 2.4 Primary supporting members........................................................... 47 2.5 Fatigue strength............................................................................. 48 3 Systems and equipment.................................................................... 48 3.1 Additional anchors.......................................................................... 48 3.2 Watertight seals for propeller axle and rudder stock............................ 48 4 Stability............................................................................................. 48 4.1 Stability requirements in transit condition.......................................... 48 4.2 Intact stability criteria in temporarily submerged conditions..................49

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 5

Part 5 Chapter 10 Contents

1 Introduction.......................................................................................44

5 Openings and closing appliances....................................................... 50 5.1 Freeboard assignment transit draught............................................... 50 5.2 Temporarily submerged conditions.................................................... 50 5.3 Reserve buoyancy........................................................................... 50 5.4 Requirements for water- and weathertight integrity.............................51 5.5 Miscellaneous requirements..............................................................52 6 Fire safety and lifesaving appliances................................................. 52 6.1 Fire extinguishing equipment............................................................52 6.2 Escape ways.................................................................................. 53 6.3 Location of survival craft................................................................. 53 7 Navigation and communication..........................................................53 7.1 Navigation......................................................................................53 Section 6 Diving support vessels.......................................................................... 54 1 Introduction.......................................................................................54 1.1 Introduction................................................................................... 54 1.2 Scope............................................................................................ 54 1.3 Application..................................................................................... 54 1.4 Survey and testing requirements...................................................... 55 1.5 Classification of diving systems........................................................ 56 1.6 Quality management....................................................................... 56 1.7 Pre-classification............................................................................. 57 1.8 Marking and signboards...................................................................57 1.9 Design philosophy and premises....................................................... 58 1.10 Handling of diving systems not certified by the Society...................... 60 2 Hull.................................................................................................... 62 2.1 Supporting structure for diving system equipment.............................. 62 3 Stability and floatation...................................................................... 63 3.1 General..........................................................................................63 4 Position keeping................................................................................ 64 4.1 General..........................................................................................64 5 Life support....................................................................................... 64 5.1 Piping............................................................................................ 64 5.2 Gas storage................................................................................... 65 6 Power provisions, control and communications................................. 65 6.1 Electrical systems........................................................................... 65 6.2 Communication............................................................................... 65 7 Fire protection................................................................................... 66

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 6

Part 5 Chapter 10 Contents

4.3 Damage stability in temporarily submerged conditions......................... 49

7.2 Fire detection and alarm systems..................................................... 66 7.3 Fire extinguishing........................................................................... 67 7.4 Miscellaneous equipment................................................................. 67 8 Hyperbaric evacuation....................................................................... 68 8.1 General..........................................................................................68 Section 7 Seismographic research vessels............................................................ 69 1 Introduction.......................................................................................69 1.1 Introduction................................................................................... 69 1.2 Scope............................................................................................ 69 1.3 Application..................................................................................... 69 2 Racking of seismic hangar.................................................................69 2.1 Transverse racking.......................................................................... 69 3 Loads................................................................................................. 70 3.1 Loads for racking strength assessment of seismic hangar in transit condition............................................................................................. 70 3.2 Loads for primary supporting members............................................. 71 4 Hull local scantling............................................................................ 73 4.1 Primary supporting members being part of seismic equipment hangar.... 73 4.2 Supporting structures for seismic handling equipment......................... 74 4.3 Strengthening for side-by-side mooring............................................. 74 5 Systems and equipment.................................................................... 75 5.1 Work boat davits and winches.......................................................... 75 5.2 High pressure air system................................................................. 75 Section 8 Well stimulation vessels........................................................................77 1 Introduction.......................................................................................77 1.1 Introduction................................................................................... 77 1.2 Scope............................................................................................ 77 1.3 Application..................................................................................... 77 2 Hull.................................................................................................... 77 2.1 General..........................................................................................77 3 Arrangement...................................................................................... 77 3.1 Tanks and pumping arrangement...................................................... 77 3.2 Tank venting.................................................................................. 78 3.3 Access openings............................................................................. 78 3.4 Acid spill protection.........................................................................78 3.5 Drainage........................................................................................ 78 4 Ventilation......................................................................................... 79

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 7

Part 5 Chapter 10 Contents

7.1 Fire prevention............................................................................... 66

4.2 Ventilation of other spaces containing equipment for well stimulation..... 79 5 Electrical equipment, instrumentation and emergency shut-down system.................................................................................................. 79 5.1 Electrical equipment or other ignition sources in enclosed spaces containing acid tanks and acid pumping arrangements.............................. 79 5.2 Vapour detection.............................................................................79 5.3 Gauging and level detection............................................................. 79 5.4 Emergency shut-down system.......................................................... 80 6 Liquid nitrogen system...................................................................... 80 6.1 Materials........................................................................................ 80 6.2 Storage tanks.................................................................................80 6.3 Pumping and piping........................................................................ 80 7 Acid system....................................................................................... 80 7.1 Materials........................................................................................ 80 7.2 Storage tanks.................................................................................80 7.3 Pumping and piping........................................................................ 80 8 Personnel protection..........................................................................81 8.1 Decontamination showers and eye washes......................................... 81 8.2 Personnel protective equipment........................................................ 81 9 Intact and damage stability...............................................................81 9.1 General..........................................................................................81 10 Operation manual............................................................................ 81 10.1 General........................................................................................ 81 Section 9 Fire fighters...........................................................................................82 1 Introduction.......................................................................................82 1.1 Introduction................................................................................... 82 1.2 Scope............................................................................................ 82 1.3 Application..................................................................................... 82 1.4 Testing requirements....................................................................... 83 2 Basic requirements............................................................................ 83 2.1 Operation manual........................................................................... 83 2.2 Manoeuvrability.............................................................................. 84 2.3 Searchlights................................................................................... 84 3 Protection of the vessel against external heat radiation.................... 84 3.1 Active fire protection (class notation qualifiers I and I+)..................... 84 3.2 Passive fire protection - class notation qualifier I+ only....................... 85 4 Water monitor system....................................................................... 85

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 8

Part 5 Chapter 10 Contents

4.1 Ventilation of spaces containing installations for storage or handling of acid.................................................................................................... 79

4.2 Arrangement.................................................................................. 86 4.3 Monitor control............................................................................... 86 4.4 Design and support of monitors........................................................86 5 Foam monitor system - class notation qualifier III............................87 5.1 Capacities...................................................................................... 87 5.2 Arrangement.................................................................................. 87 5.3 Monitor control............................................................................... 87 5.4 Monitor design................................................................................87 6 Pumps and piping.............................................................................. 87 6.1 General..........................................................................................87 6.2 Pumps........................................................................................... 88 6.3 Seawater inlets and sea chests........................................................ 88 6.4 Piping systems............................................................................... 88 7 Mobile fire fighting equipment...........................................................89 7.1 Fire hydrants manifolds and hoses for external use............................. 89 7.2 Foam generator.............................................................................. 90 8 Fire fighter’s outfit............................................................................ 90 8.1 Number and extent of the outfits......................................................90 8.2 Location of the fire fighter’s outfits................................................... 90 8.3 Compressed air supply.................................................................... 91 9 Stability and watertight integrity...................................................... 91 9.1 General requirements...................................................................... 91 Section 10 Icebreaker........................................................................................... 92 1 Introduction.......................................................................................92 1.1 Introduction................................................................................... 92 1.2 Scope............................................................................................ 92 1.3 Application..................................................................................... 92 2 General principles.............................................................................. 92 3 General arrangement......................................................................... 92 3.1 Bow form.......................................................................................92 3.2 Stem and stern region.................................................................... 92 3.3 Position of collision bulkhead............................................................93 4 Structural design............................................................................... 94 4.1 Materials........................................................................................ 94 5 Loads................................................................................................. 94 5.1 Hull area factors............................................................................. 94 6 Longitudinal hull girder strength....................................................... 96

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 9

Part 5 Chapter 10 Contents

4.1 Capacities...................................................................................... 85

7.1 General..........................................................................................96 7.2 Overall strength of substructure in fore ship.......................................96 8 Stability............................................................................................. 96 8.1 General..........................................................................................96 8.2 Intact stability................................................................................ 96 8.3 Requirements for watertight integrity................................................ 96 9 Machinery.......................................................................................... 97 9.1 Propeller ice interaction................................................................... 97 9.2 Design ice loads for open propeller................................................... 97 9.3 Design ice loads for propulsion line................................................... 98 9.4 Fatigue evaluation of propulsion line................................................. 99 9.5 Steering system............................................................................. 99 Section 11 Tugs and escort vessels.................................................................... 100 1 Introduction..................................................................................... 100 1.1 Introduction..................................................................................100 1.2 Scope.......................................................................................... 100 1.3 Application................................................................................... 100 1.4 Class notations............................................................................. 100 1.5 Testing requirements..................................................................... 101 2 Hull arrangement and strength....................................................... 104 2.1 Draught for scantlings................................................................... 104 2.2 Fore body, bow structure............................................................... 104 2.3 Side structure...............................................................................105 2.4 Engine room casing, superstructures and deckhouses........................ 105 2.5 Foundations of towing gear............................................................ 105 2.6 Deck structure.............................................................................. 106 2.7 Stern frame..................................................................................106 3 Systems and equipment.................................................................. 106 3.1 Anchoring and mooring equipment.................................................. 106 3.2 Steering gear/steering arrangement................................................ 106 3.3 Towing gear/towing arrangement.................................................... 107 3.4 Materials for equipment................................................................. 108 3.5 Towing hook and quick release....................................................... 108 3.6 Towlines....................................................................................... 109 3.7 Towing winch................................................................................ 109 3.8 Marking........................................................................................111 4 Fire safety and escape routes..........................................................111

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 10

Part 5 Chapter 10 Contents

7 Hull local scantlings...........................................................................96

4.2 Companionways............................................................................ 111 4.3 Rudder compartment..................................................................... 111 4.4 Access to bridge........................................................................... 111 4.5 Fire safety....................................................................................111 5 Stability and openings and closing appliances................................. 111 5.1 General stability requirements........................................................ 111 5.2 Openings and closing appliances..................................................... 113 6 Additional requirements for escort tugs.......................................... 113 6.1 General........................................................................................ 113 6.2 Hull arrangement.......................................................................... 114 6.3 Equipment.................................................................................... 115 6.4 Propulsion system......................................................................... 115 6.5 General stability requirements........................................................ 116 6.6 Additional stability criteria.............................................................. 116 6.7 Load line......................................................................................117 6.8 Methods for establishing the escort rating number (Fs, t, v)............... 117 6.9 Full scale testing requirements for notation Escort tug (F, (FS, t, v)). 117 6.10 Numerical calculations for notation Escort tug (N, (FS, t, v)).......... 118 Section 12 Dredgers............................................................................................ 119 1 Introduction..................................................................................... 119 1.1 Introduction..................................................................................119 1.2 Scope.......................................................................................... 119 1.3 Application................................................................................... 119 2 Hull arrangement and strength....................................................... 120 2.1 General requirements.................................................................... 120 2.2 Hull girder strength....................................................................... 120 2.3 Hull local scantlings.......................................................................120 2.4 Single bottom - transversely stiffened............................................. 121 2.5 Single bottom - longitudinally stiffened............................................ 121 2.6 Double bottom..............................................................................122 2.7 Hopper and well construction......................................................... 123 2.8 Box keel...................................................................................... 124 3 Systems and equipment.................................................................. 124 3.1 Stern frame..................................................................................124 3.2 Rudder stock................................................................................ 125 3.3 Anchoring and mooring equipment.................................................. 125 4 Fire safety........................................................................................125

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 11

Part 5 Chapter 10 Contents

4.1 Emergency exit from engine room.................................................. 111

5 Openings and closing appliances..................................................... 125 5.1 General requirements.................................................................... 125 5.2 Bulwark, overflow arrangements..................................................... 125 Section 13 Pushers..............................................................................................127 1 Introduction..................................................................................... 127 1.1 Introduction..................................................................................127 1.2 Scope.......................................................................................... 127 1.3 Application................................................................................... 127 2 Definitions........................................................................................127 2.1 Terms.......................................................................................... 127 3 Subdivision arrangement design......................................................128 3.1 Subdivision arrangement................................................................128 4 Hull.................................................................................................. 128 4.1 General........................................................................................ 128 4.2 Draught for scantlings................................................................... 128 4.3 Structure in the forebody...............................................................128 5 Equipment........................................................................................128 5.1 Rudder.........................................................................................128 5.2 Steering gear............................................................................... 129 5.3 Anchoring and mooring..................................................................129 Section 14 Slop reception vessel........................................................................ 130 1 Introduction..................................................................................... 130 1.1 Introduction..................................................................................130 1.2 Scope.......................................................................................... 130 1.3 Application................................................................................... 130 2 Hull strength and arrangement....................................................... 131 2.1 General requirements.................................................................... 131 2.2 Transfer arrangement for transfer of oily water and oil residues........... 132 2.3 Lightning...................................................................................... 132 2.4 Separating system........................................................................ 132 2.5 Oil content monitoring................................................................... 132 2.6 Protection against fire and explosion............................................... 133 3 Operational instructions and log book............................................. 133 3.1 Instruction materials..................................................................... 133 3.2 Safety and oily water/oil residues log book...................................... 135 Section 15 Refrigerated cargo vessels................................................................ 136

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 12

Part 5 Chapter 10 Contents

4.1 Closed hopper spaces.................................................................... 125

1.1 Introduction..................................................................................136 1.2 Scope.......................................................................................... 136 1.3 Application................................................................................... 136 1.4 Class notations............................................................................. 136 2 Operational performance................................................................. 137 2.1 General........................................................................................ 137 Section 16 Tanker for potable water................................................................. 138 1 General...........................................................................................138 1.1 Objective.................................................................................... 138 1.2 Scope.......................................................................................... 138 1.3 Application................................................................................... 138 1.4 Class notation...............................................................................138 1.5 Assumption.................................................................................. 138 2 Documentation.................................................................................139 2.1 General........................................................................................ 139 2.2 Certification requirements.............................................................. 140 2.3 Surveys and Testing...................................................................... 140 3 Requirement for carriage of potable water...................................... 140 3.1 Material........................................................................................140 3.2 Tank Arrangement......................................................................... 141 3.3 Piping System...............................................................................141 Changes – historic.............................................................................................. 142

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 13

Part 5 Chapter 10 Contents

1 Introduction..................................................................................... 136

Symbols For symbols and definitions not defined in this chapter, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements to vessels performing special operations including sub-sea lifting, cable and pipe laying services, heavy lift and transport, diving support, seismographic research services, well stimulation, fire-fighting, icebreaking, dredging and towing and escort services.

1.2 Scope 1.2.1 The rules in this chapter give requirements to hull strength, systems and equipment, safety and availability, stability and load line and the relevant procedural requirements applicable to vessels performing special operations.

1.3 Application 1.3.1 The requirements in this chapter shall be regarded as supplementary to those given for the assignment of main class Pt.2, Pt.3 and Pt.4.

2 Class notations 2.1 Ship type notations 2.1.1 Vessels built in compliance with the requirements as specified in Table 1 will be assigned the class notations as follows: Table 1 Ship type notations

Class notation

Crane vessel

Cable laying vessel Pipe laying vessel

Purpose Vessels specially intended for lifting operations.

Qualifier

Description

Design requirements, rule reference

<none>

Sec.1 and Sec.2

Vessels specially intended for laying cables on the sea bottom

<none>

Sec.1 and Sec.3

Vessels specially intended for laying pipelines on the sea bottom

<none>

Sec.1 and Sec.4

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 14

Part 5 Chapter 10 Section 1

SECTION 1 GENERAL

Purpose

Semi-submersible heavy transport vessel

Specially intended for loading and unloading cargo by submerging the freeboard deck through ballast operations

Diving support vessel

Vessels arranged for support of diving operations applying rope and/or umbilical connection between the submerged bell and the diving support vessel

Qualifier

Description

<none>

SAT

Surface

Design requirements, rule reference

Sec.1 and Sec.5

Vessels arranged to support diving operations with no operating restrictions Sec.1 and Sec.6 Vessels arranged to support diving operations with operating restrictions to maximum depth of 60 m and operating time 8 hours

<none> Advanced design for seismographic research. Vessels with class notation qualifier (A) shall hold the following additional class notations: Seismic vessel

Vessels designed for seismographic research

— RP(+) or RP(3,x%, +), see Pt.6 Ch.2; or A

DYNPOS(AUTR) or DYNPOS(AUTRO), see Pt.6 Ch.3;

Sec.1 and Sec.7

or DYNPOS(ER), see Pt.6 Ch.3 — E0 or ECO, see Pt.6 Ch.2 — NAUT(OSV), see Pt.6 Ch.3 Well stimulation vessel

Arranged and equipped for stimulation of wells for production of oil and/or gas

Fire fighter

Fire fighting on board ships and on offshore and onshore structures

<none>

Sec.1 and Sec.8

<none>

I

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Active protection, giving it the capability to withstand higher heat radiation loads from external fires

Sec.1 and Sec.9

Page 15

Part 5 Chapter 10 Section 1

Class notation

Purpose

Qualifier

Description

I+

Active and passive protection, giving it the capability to withstand the higher heat radiation loads also when the active protection fails. In addition, the vessel incorporates a longer throw length

II

Continuous fighting of large fires and cooling of structures. Can be assigned in combination with Fire fighter(I)

III

Continues fighting of large fires and cooling of structures with larger water pumping capacity and more comprehensive fire fighting equipment than for II. Can be assigned in combination with Fire fighter(I)

Capability

Design requirements, rule reference

Vessels with special fire fighting capabilities

Icebreaker

Vessels primarily designed for ice breaking operations

<none>

Sec.1 and Sec.10

Tug

Ships primarily designed for towing and/or pushing operations or assisting other vessels or floating objects in manoeuvring

<none>

Sec.1 and Sec.11

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 16

Part 5 Chapter 10 Section 1

Class notation

Escort tug

Purpose

Qualifier

Vessel specially intended for active escort towing. This includes steering, braking and otherwise controlling a vessel in restricted waters during speeds of up to 10 knots by means of a permanent towline connection with the stern of the escorted vessel

Description

F

Escort rating numbers based on full scale test

N

Escort rating numbers based on numerical calculations

O

Escort rating numbers established by another classification society

Design requirements, rule reference

(FS, t, v) are escort rating numbers, where: FS indicates maximum transverse steering pull in ton, exerted by the escort tug on the stern of the assisted vessel (FS, t, v)

Sec.1 and Sec.11

t is the time in seconds required for the change of the tug's position from one side to the corresponding opposite side v is the speed in knots at which this pull may be attained

Dredger

Vessels which are selfpropelled or non-selfpropelled and which are designed for all common dredging methods (e.g. bucket dredging, grab dredging etc.)

Pusher

Vessels primarily designed for pushing

<none>

Suction

Vessels which are selfpropelled or non-selfpropelled and which are designed for suction dredging

Sec.1 and Sec.12

Sec.1 and Sec.13

2.2 Additional notations 2.2.1 The following additional notations, as specified in Table 2, are typically applied to vessels performing special operations: Table 2 Additional notations Class notation

NAUT

Description Requirements for bridge design, instrumentation, location of equipment and bridge procedures for enhanced safety for manoeuvring of the ship

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Application

All ships

Rule reference

Pt.6 Ch.3

Page 17

Part 5 Chapter 10 Section 1

Class notation

Description

Application

Rule reference

SPS

Ships carrying special personnel who are neither crew members nor passengers

Case by case

Pt.6 Ch.5 Sec.7

Clean

Vessel designed for controlling and limiting operational emissions and discharges

All ships

Pt.6 Ch.7 Sec.2

DYNPOS

Vessel equipped with dynamic positioning system

All ships

COMF

Comfort class covering requirements for noise and vibration and indoor climate

All ships

Pt.6 Ch.8 Sec.1

HELDK

Requirements to helicopter landing area or erected platform covering basic strength requirements and safety

All ships

Pt.6 Ch.5 Sec.5

Crane

Requirements to certification of crane

All ships except for Crane vessel

Pt.6 Ch.5 Sec.3

SF

Compliance with the damage stability requirements of IMO Res.MSC.235(82) (Guidelines for the Design and Construction of Offshore Supply Vessels, 2006), Offshore service vessel alternatively as amended by IMO Res. MSC.335(90) (Amendments to the Guidelines for the Design and Construction of Offshore Supply Vessels, 2006)

Pt.6 Ch.5 Sec.6

Strengthened(DK)

Decks strengthened for heavy cargo

Pt.6 Ch.1 Sec.2

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

All ships

Pt.6 Ch.3 Sec.2 Pt.6 Ch.3 Sec.3

Page 18

Part 5 Chapter 10 Section 1

Class notation

3.1 Terms 3.1.1 Table 3 Definitions of terms Terms cargo deck on semi-submersible heavy transport vessel

Definition the deck being submerged for carrying the cargo, as well as its horizontal extension

exposed surfaces

superstructures, casings and other buoyant volumes above the cargo deck, or its horizontal extension, that may become damaged if coming in contact with the cargo at any stage during loading or unloading operations The cargo deck is also to be considered as an exposed surface.

maximum submerged draught

the maximum draught to which the vessel is allowed to be submerged

semi-submersible heavy transport a vessel designed to load and unload deck cargo by temporarily submerging its cargo vessel deck through ballast operations temporarily submerged condition

any ballasting or de-ballasting with the load line mark submerged

transit condition

the condition from when the vessel has completed loading, with the cargo properly secured, to when the vessel has reached its intended destination and preparation for unloading can commence

control stand

is a station in which one or more of the following control or indicating functions are centralized: 1)

indication and operation of all vital life support conditions, including pressure control

2)

visual observation, communication systems including telephones, audiorecording and microphones to public address systems

3)

disconnection of all electrical installations and Insulation monitoring

4)

provisions for calibration of and comparison between gas analysing

5)

indication of temperature and humidity in the inner area

6)

alarms for abnormal conditions of environmental control systems

7)

fixed fire detection and fire alarm systems

8)

ventilation fans

9)

automatic sprinkler, fire detection and fire alarm systems

10) launch and recovery systems, including interlock safety functions 11) operation and control of the hyperbaric evacuation system fore ship substructure

fore ship substructure includes bow area B and bow intermediate ice belt BIi as defined in Pt.6 Ch.6 Sec.5 Figure 1

towline

rope/wire used for towing

escort service

the service includes steering, braking and otherwise controlling the assisted vessel. The steering force is provided by the hydrodynamic forces acting on the tug's hull.

escort test speed

this is the speed at which the full scale measurements shall be carried out, normally 8 knots and/or 10 knots

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 19

Part 5 Chapter 10 Section 1

3 Definitions

Definition

escort tug

the tug performing the escort service, while assisted vessel is the vessel being escorted

bollard pull (BP)

maximum continuous pull obtained at static pull test on sea trial

dredger

means all hopper dredgers, hopper barges and similar vessels which may be selfpropelled or non-self-propelled and which are designed for all common dredging methods (e.g. bucket dredging, suction dredging, grab dredging etc.).

3.1.2 For symbols and definitions concerning diving vessels, refer to the Society's documents: DNVGLCP-0354, DNVGL-OS-E402 and DNVGL-CP-0355.

4 Documentation 4.1 Documentation requirements 4.1.1 General For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 4.1.2 Crane vessel Documentation shall be submitted as required by Table 4. Table 4 Documentation requirements - Crane vessel Object

Documentation type

Additional description

Info

Including: — main dimensions — limiting positions of movable parts — dynamic load charts including safe working loads and corresponding arms

Z030 - Arrangement plan

FI

— location on board during operation and in parked position. — plan of rack bar (toothed bar) with details of support, if applicable. Cranes H050 - Structural drawing

Crane pedestals including design loads and reaction forces: — during operation

AP

— in stowed position.

H050 - Structural drawing

Crane supporting structures including design loads and reaction forces: — during operation

AP

— in stowed position. E170 - Electrical schematic drawing

Including cable list.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

AP

Page 20

Part 5 Chapter 10 Section 1

Terms

Documentation type

Additional description

Info

I200 - Control and monitoring system documentation

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

4.1.3 Cable laying vessel Documentation shall be submitted as required by Table 5. Table 5 Documentation requirements - Cable laying vessel Object

Documentation type

Additional description

Info

Including:

Cable laying equipment

— safe working loads/brake rendering loads

C010 - Design criteria

FI

— load directions and points of exertion — dynamic amplification factors — description of operational features.

Z030 - Arrangement plan

Cable laying equipment supporting structures

FI

H050 - Structural drawing

Including footprint loads from pipe laying equipment.

AP

C010 - Design criteria

Stowed cable supporting structure: Maximum weight of stowed cables.

FI

H050 - Structural drawing

Stowed cable supporting structure.

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

If an anchoring system for position-keeping is installed, additional documentation shall be submitted as required by Table 6. Table 6 Additional document requirements for ships with anchoring system for position keeping Object

Documentation type

Additional description

Info

C010 – Design criteria

Applicable if anchoring system is used for position keeping. Including anchor line forces.

FI

Z030 – Arrangement plan

Applicable if anchoring system is used for position keeping. Including limiting anchor line angles.

FI

Anchoring system for position keeping: Including supporting structure for winches and force transmitting structures at points where the anchor lines change direction.

AP

Anchor racks for stowage for mooring anchor during voyage at sea.

AP

Anchoring arrangement H050 - Structural drawing

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 21

Part 5 Chapter 10 Section 1

Object

Documentation type

Additional description

Info

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 22

Part 5 Chapter 10 Section 1

Object

Table 7 Documentation requirements - Pipe laying vessel Object

Documentation type

Additional description

Info

Including:

Pipe laying arrangement

C010 – Design criteria

— safe working loads/brake rendering loads

FI

— load directions and points of exertion — dynamic amplification factors — description of operational features.

Z030 – Arrangement plan Pipe laying equipment supporting structures

Pipe reel

Pipe stowage equipment

FI

H050 – Structural drawing

Including footprint loads from pipe laying equipment.

AP

C010 – Design criteria

Including maximum weight of reel with pipe, including water if the pipe shall be hydraulically tested on board.

FI

H050 – Structural drawing

Pipe reel supporting structure.

AP

C010 – Design criteria

Including maximum weight of stowed pipes.

FI

H050 – Structural drawing

Stowed pipe supporting structure.

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

If an anchoring system for position-keeping is installed, additional documentation shall be submitted as required by Table 8. Table 8 Additional document requirements for ships with anchoring system for position keeping Object

Anchoring arrangement

Documentation type

Additional description

Info

C010 – Design criteria

Applicable if anchoring system is used for position keeping. Including anchor line forces.

FI

Z030 – Arrangement plan

Applicable if anchoring system is used for position keeping. Including limiting anchor line angles.

FI

H050 – Structural drawing

Anchoring system for position keeping: Including supporting structure for winches and forcetransmitting structures at points where the anchor lines change direction.

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 23

Part 5 Chapter 10 Section 1

4.1.4 Pipe laying vessel Documentation shall be submitted as required by Table 7.

Table 9 Documentation requirements - Semi-submersible heavy transport vessel Object Ship hull structure

Stability

External watertight and weathertight integrity

Documentation type

Additional description Maximum submerged draught, maximum transit draught and minimum transit draught with cargo.

Z100 – Specification

Info FI

B030 – Internal watertight integrity plan

FI

B070 – Preliminary damage stability calculation

AP

Stability calculations in accordance with Sec.5 [4] for B130 – Final damage stability transit and temporarily submerged conditions. calculation Z265 – Calculation report

Reserve buoyancy calculations.

AP FI

G120 – Escape route drawing

AP

S010 – Piping diagram (PD)

AP

S030 – Capacity analysis

AP

Z030 – Arrangement plan

AP

Helicopter deck foam fire extinguishing system

G200 – Fixed fire extinguishing system documentation

AP

Machinery spaces fixed water spaying fire extinguishing system

G200 – Fixed fire extinguishing system documentation

AP

Cargo holds water spraying fire extinguishing system

G200 – Fixed fire extinguishing system documentation

AP

Navigation systems

Z090 - Equipment list

AP

N010 – Bridge design drawing

AP

N020 – Vertical field of vision drawing

AP

N030 – Horizontal field of vision drawing

AP

Z090 – Equipment list

AP

Internal communication systems

Z030 – Arrangement plan

AP

Vessel operation

Z250 – Procedure

Escape routes

Fire water system

Navigation bridge

Submersion operation, including generic ballasting sequence during submersion and re-emersion.

FI

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 24

Part 5 Chapter 10 Section 1

4.1.5 Semi-submersible heavy transport vessel Documentation shall be submitted as required by Table 9.

Table 10 Documentation requirements - Diving support vessel Object

Damage stability

Cables and umbilicals

Explosion (Ex) protection

Structural fire protection arrangements

Fire detection and alarm system

Fire water system

Ventilation systems

Documentation type

Additional description

Info

B030 – Internal watertight integrity plan

FI

B070 – Preliminary damage stability calculation

AP

B130 – Final damage stability calculation

AP

E030 – Cable selection philosophy

AP

E170 – Electrical schematic drawing

Single line diagrams for all intrinsically safe circuits, for each circuit including data for verification of the compatibility between the barrier and the field components.

AP

Z030 – Arrangement plan

Electrical equipment in hazardous areas. Where relevant, based on an approved hazardous area classification drawing where location of electric equipment in hazardous area is added (except battery room, paint stores and gas bottle store).

AP

E250 – Explosion protected equipment maintenance manual

AP

G060 – Structural fire protection drawing

AP

G061 – Penetration drawing

AP

I200 – Control and monitoring system

AP

Z030 – Arrangement plan

AP

S010 – Piping diagram (PD)

AP

Z030 – Arrangement plan

AP

S030 – Capacity analysis

AP

S012 – Ducting diagram (DD)

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 25

Part 5 Chapter 10 Section 1

4.1.6 Diving support vessel Documentation shall be submitted as required by Table 10.

Table 11 Documentation requirements - Seismic vessel Object

Seismic handling equipment

Seismic equipment supporting structures

Work boat davits, Work boat winches

Work boat davits and winches supporting structures

Documentation type

Additional description

Info

C010 – Design criteria

Design loads (safe working load, fleet angles, brake rendering load and wire breaking load as relevant). Self weights of equipment in operational and in transit modes.

FI

Z030 – Arrangement plan

Heavy machinery in hangar and on deck and equipment for handling and storage and mooring at sea.

FI

Z265 – Calculation report

Hangar: Design loads and racking calculations covering operational and transit modes.

FI

H050 – Structural drawing

Including foundations. Design loads, footprint loads and fastening details.

AP

C060 – Mechanical Including: Safe working load, heel/trim if applicable component documentation and dynamic factor if above 1.5.

AP

Z161 – Operation manual

FI

Z162 – Installation manual

FI

Z163 – Maintenance manual

FI

H050 – Structural drawing

Including foundations. Design loads, footprint loads and fastening details.

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 26

Part 5 Chapter 10 Section 1

4.1.7 Seismic vessel Documentation shall be submitted as required by Table 11.

Table 12 Documentation requirements - Well stimulation vessel Object Cargo compartments

Cargo tank arrangements, independent

Cargo independent tank arrangements type C

Damage stability

Ventilation systems for hazardous cargo areas

Documentation type

Additional description

Info

Z030 – Arrangement plan

Tanks for well stimulation.

FI

H050 – Structural drawing

Acid tanks, including lining specification.

AP

H050 – Structural drawing

Support and staying.

AP

C050 – Non-destructive testing (NDT) plan

Acid tanks.

FI

H050 – Structural drawing

Including supports and anti-flotation arrangement.

AP

B030 – Internal watertight integrity plan

FI

B070 – Preliminary damage stability calculation

AP

B130 – Final damage stability calculation

AP

S012 – Ducting diagram (DD)

Closed and semi-enclosed spaces containing acid tanks, pipes, pumps and mixing units.

AP

C030 – Detailed drawing

Drawings and particulars including stress analysis of nitrogen vaporiser.

FI

S010 – Piping diagram (PD)

Acid, nitrogen and liquid additives.

AP

Cargo piping

S070 – Pipe stress analysis

Piping for liquid nitrogen and other high pressure piping.

FI

Cargo hoses

Z100 – Specification

High pressure flexible hoses with end connections.

FI

Cargo main pumping arrangement

C030 – Detailed drawing

Including mixers.

FI

Cargo handling arrangement

Z161 – Operation manual

Well stimulation procedures.

AP

Cargo compartments over- and under pressure prevention arrangements

S010 – Piping diagram (PD)

AP

Emergency shut down (ESD) system

I200 – Control and monitoring system documentation

AP

Hydrogen gas detection and alarm system, fixed

I200 – Control and monitoring system documentation

AP

Oxygen indication system, fixed sample extraction

I200 – Control and monitoring system documentation

AP

Toxic gases detection and alarm system

I200 – Control and monitoring system documentation

Cargo piping system

Hydrogen chloride.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

AP

Page 27

Part 5 Chapter 10 Section 1

4.1.8 Well stimulation vessel Documentation shall be submitted as required by Table 12.

Documentation type

Additional description

Info

Cargo tanks level monitoring system

I200 – Control and monitoring system documentation

AP

Cargo tanks overflow protection system

I200 – Control and monitoring system documentation

AP

Hazardous area classification

G080 – Hazardous area classification drawing

AP

E250 – Explosion protected equipment maintenance manual

AP

E170 – Electrical schematic drawing

Single line diagrams for all intrinsically safe circuits, for each circuit including data for verification of the compatibility between the barrier and the field components.

AP

Z030 – Arrangement plan

Electrical equipment in hazardous areas. Where relevant, based on an approved hazardous area classification drawing where location of electric equipment in hazardous area is added (except battery room, paint stores and gas bottle store).

AP

Explosion (EX) protection

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

4.1.9 Fire fighter Documentation shall be submitted as required by Table 13. Table 13 Documentation requirements - Fire fighter Object

Documentation type

Additional description

Relevance for qualifier

Info

Sea chest

Z030 – Arrangement plan

Fire fighting pumps.

All

AP

Structural fire protection arrangements

G060 – Structural fire protection drawing

Outer boundaries, including external doors and windows.

I+

AP

Fire fighting systems

Z161 – Operation manual Z163 – Maintenance manual

FIFI operation.

All

AP

All

AP

I, I+

AP

All

AP

Fire water supply and distribution arrangement

S010 – Piping diagram S030 – Capacity analysis Z030 – Arrangement plan

External surface protection water spraying fire extinguishing system

G200 – Fixed fire extinguishing system documentation

Fire fighting vessel fire extinguishing system

H050 – Structural drawing

Supporting structure for pumps, pump drivers and monitors.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 28

Part 5 Chapter 10 Section 1

Object

Info

G200 – Fixed fire extinguishing system documentation

Including specification of height and length of throw. Including location of pumps, pump drivers, monitors, hose connections and hose stations.

All

AP

I100 – System diagram

Control system for fire fighting monitors.

All

AP

Portable foam generator

Z100 – Specification

Foam generator and containers for storage of foam concentrate.

II, III

AP

Fire-fighter's outfit

Z030 – Arrangement plan

All

AP

Breathing air compressor unit

Z030 – Arrangement plan

All

AP

Flood light

Z030 – Arrangement plan Z100 – specification

All

AP

Fire fighting vessel monitor water spraying fire extinguishing system

Documentation type

Additional description

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

4.1.10 Icebreaker Documentation shall be submitted as required by Table 14. Table 14 Documentation requirements - Icebreaker Object

Documentation type

Additional description

Info

— description of main propulsion, steering, emergency and essential auxiliaries including operational limitations and information on essential main propulsion load control functions

FI

Including:

Technical information

Z100 – Specification

— description detailing how main, emergency and auxiliary systems are located and protected to prevent problems from freezing, ice and snow and evidence of their capability to operate in intended environmental conditions. Including: — UIWL and LIWL — ship’s displacement at UIWL

Hull structure

H110 – Preliminary loading manual

— loading conditions with respect to strength and stability — design speed

AP

— ramming speed — instruction for filling of ballast tanks — astern operation in ice — design temperature, see guidance note.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 29

Part 5 Chapter 10 Section 1

Relevance for qualifier

Object

Documentation type

Additional description

Info

Propulsion torque and thrust transmission arrangement

C040 – Design analysis

Ice load response simulation.

AP

Propeller arrangements

C040 – Design analysis

Finite element analysis of blade stresses introduced by ice loads.

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific Guidance note: The design temperature reflects the lowest mean daily average air temperature in the intended area of operation. An extreme air temperature about 20°C below this may be tolerable to the structures and equipment from a material point of view. For calculations where the most extreme temperature over the day is relevant, the air temperature can be set 20°C lower than the design temperature in the notation. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.11 Tug Documentation shall be submitted as required by Table 15. Table 15 Documentation requirements - Tug Object

Document type

Additional description

Info

Including:

Z030 – Arrangement plan

— towline paths showing extreme sectors and wrap on towing equipment towline points of attack — maximum expected BP

FI

— maximum design load for each component

Towing arrangement

— emergency release capabilities. Z253 – Test procedure for quay and sea trial

Bollard pull.

AP, L

Z253 – Test procedure for quay and sea trial

Winch and other equipment required by the class notation.

AP, L

Including: — design force T and the expected maximum BP C010 – Design criteria

— hoisting capacity, rendering and braking force of the winch

FI

— release capabilities (response time and intended remaining holding force after release). Towing winch

C020 – Assembly or arrangement drawing

FI

C030 – Detailed drawing

AP

C040 – Design analysis

Strength calculation of the drum with flanges, shafts with couplings, framework and brakes.

C050 – Non-destructive testing (NDT) plan

FI AP

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 30

Part 5 Chapter 10 Section 1

Object

Document type C010 – Design criteria

Additional description The expected maximum BP shall be stated.

C020 – Assembly or arrangement drawing Towing hook

Towing winch supporting structure, Towing hook supporting structure

C030 – Detailed drawing

Info FI FI

Including emergency release mechanism.

AP

C040 – Design analysis

FI

C050 – Non-destructive testing (NDT) plan

AP

H050 – Structural drawing

The design force T and the expected maximum BP shall be stated. Including footprint. Applicable for equipment with static force > 50 kN or bending moment > 100 kNm.

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

4.1.12 Escort tug Documentation shall be submitted as required in [4.1.11] and Table 16. Table 16 Documentation requirements - Escort tug Object

Vessel

Documentation type

Info

Z253 – Test procedure for quay and sea trial

Applicable for qualifier F only.

FI

Z263 – Report from quay and sea trial

Applicable for qualifier F only.

FI

Z030 – Arrangement plan

Including layout of vessels and towline path with thetabeta angles.

FI

Z265 – Calculation report

Towing forces, including FW, FS and FB as described in Sec.11 Figure 1.

FI

Z100 – Specification

Minimum breaking strength/safe working load for tow line and associated components, fixations and supporting structures.

FI

Towing arrangement

Tow line

Additional description

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

4.1.13 Dredgers Documentation shall be submitted as required by Table 17. Table 17 Documentation requirements - Dredger Object

Documentation type

Additional description

Info

Dredging equipment supporting structure

H050 – Structural drawing

Including design loads.

AP

Dredging arrangement

Z030 – Arrangement plan

Including dredging equipment and installations.

FI

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 31

Part 5 Chapter 10 Section 1

Object

Documentation type

Additional description

Info

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

4.1.14 Pusher Documentation shall be submitted as required by Table 17. Table 18 Documentation requirements - Pusher Object

Documentation type

Additional description

Info

Pushing arrangement

Z030 – Arrangement plan

Pusher/barge unit.

FI

Pushing arrangement

H080 – Strength analysis

In connection equipment and on contact areas.

FI

Pusher-barge connection arrangement on pusher

Z030 – Arrangement plan

FI

Pusher-barge connection on pusher

H050 – Structural drawing

AP

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

5 Certification 5.1 Certification requirements 5.1.1 General For a definition of the certificate types, see Pt.1 Ch.3 Sec.4 and Pt.1 Ch.3 Sec.5. 5.1.2 Crane vessel Products shall be certified as required by Table 19 Table 19 Certification required for Crane vessel Object

Crane

Certificate type

PC

Issued by

Society

Certification standard*

DNVGL-ST-0378 Standard for offshore and platform lifting appliances

Additional description In agreement with the Society the crane may be certified based on other internationally recognised standards. Cranes certified by other Societies may be accepted based on special consideration.

* Unless otherwise specified the certification standard is the rules

5.1.3 Cable laying vessel Equipment subjected to cable loads when the vessel is in operation shall be certified as required by Table 20. Cable handling equipment which is not used while the vessel is in operation, e.g. spooling towers, need not be certified.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 32

Part 5 Chapter 10 Section 1

Object

Object

Cable laying equipment

Electrical equipment

Certificate type

PC

PC

Issued by

Certification standard*

Additional description

DNVGL-ST-0378 Standard for offshore and platform lifting appliances

Society

Associated electrical equipment (motors, frequency converters, switchgear and control gear) serving an item that is required to be delivered with the Society's product certificate is also required to have a DNV GL product certificate. Such electrical equipment is regarded as important equipment, see Pt.4 Ch.8 Sec.1 [2.3.2].

Society

* Unless otherwise specified the certification standard is the rules

5.1.4 Pipe laying vessel Equipment subjected to pipe loads when the vessel is in operation shall be certified as required by Table 21. Pipe handling equipment which is not used while the vessel is in operation, e.g. spooling towers, need not be certified. Table 21 Certification required for Pipe laying vessel Object

Pipe laying equipment

Electrical equipment

Certificate type

PC

PC

Issued by

Certification standard*

Additional description

DNVGL-ST-0378 Standard for offshore and platform lifting appliances

Society

Associated electrical equipment (motors, frequency converters, switchgear and control gear) serving an item that is required to be delivered with a the Society's product certificate is also required to have a DNV GL product certificate. Such electrical equipment is regarded as important equipment, see Pt.4 Ch.8 Sec.1 [2.3.2].

Society

* Unless otherwise specified the certification standard is the rules

5.1.5 Seismic vessel Products shall be certified as required by Table 22.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 33

Part 5 Chapter 10 Section 1

Table 20 Certification required for Cable laying vessel

Object Work boats

Certificate type

Issued by

PC

Society

DNVGL-ST-0342 Craft DNVGL-ST-0378 Standard for offshore and platform lifting appliances

Wide tow equipment

PC

Society

Handling and towing booms

PC

Society

PC

Society

MC

Society

PC

Society

MC

Society

Work boat davits

Work boat winches

Electrical equipment

PC

Certification standard*

Part 5 Chapter 10 Section 1

Table 22 Certification requirements for Seismic vessel Additional description

Or material certificate 3.1 according to ISO 10474

Or material certificate 3.1 according to ISO 10474 Associated electrical equipment (motors, frequency converters, switchgear and control gear) serving an item that is required to be delivered with the Society's product certificate is also required to have a DNV GL product certificate. Such electrical equipment is regarded as important equipment, see Pt.4 Ch.8 Sec.1 [2.3.2].

Society

* Unless otherwise specified the certification standard is the rules

5.1.6 Well stimulation vessel Products shall be certified as required by Table 23. Table 23 Certification requirements for Well stimulation vessel Object

Certificate type

Issued by

PC

Society

Certification standard*

Additional description

Cargo tank level measurement system Cargo tank overflow protection system Emergency shut-down system

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 34

Electrical equipment

Certificate type

PC

Issued by

Certification standard*

Additional description Associated electrical equipment (motors, frequency converters, switchgear and control gear) serving an item that is required to be delivered with the Society's product certificate is also required to have a DNV GL product certificate. Such electrical equipment is regarded as important equipment, see Pt.4 Ch.8 Sec.1 [2.3.2].

Society

* Unless otherwise specified the certification standard is the rules

5.1.7 Fire fighter Products shall be certified as required by Table 24. Table 24 Certification requirements for Fire fighter Certificate type

Issued by

Fire fighting pumps and their prime movers

PC

Society

Compressor for recharging the breathing air cylinders

PC

Society

Pipes and valves

MC

Manufacturer

Foam concentrate suitable for its intended use

TR

Recognized test laboratory

Object

Certification standard*

Additional description

MSC/Circ.670 or MSC.1/Circ.1312 as applicable

* Unless otherwise specified the certification standard is the rules

5.1.8 Tug and Escort tug Products shall be certified as required by Table 25. Table 25 Certification requirements for Tug Object Towing winch Towing hook

Certificate type

Issued by

PC

Society

Towing hook Winch Shafts for drum Brake

MC

Society

Certification standard*

Additional description

Material certificate type For load transmitting elements, 3.1 according to ISO including slip device. 10474 may be accepted Including drum and flanges. for standard items if the manufacturer is approved by the Society

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 35

Part 5 Chapter 10 Section 1

Object

Certificate type

Issued by

Certification standard*

Additional description

Couplings Winch frame

Manufacturer

Gear shaft and wheels Tow ropes

Including breaking force.

* Unless otherwise specified the certification standard is the rules

5.1.9 Pusher Products shall be certified as required by Table 24. Table 26 Certification requirements for Pusher Object

Pusher - barge connection on pusher

Pusher - barge connection on barge

Certificate type

Issued by

PC

Society

PC

Manufacturer

PC

Society

PC

Manufacturer

Certification standard*

Additional description Locking devices in type I connection system. Steel wire ropes or other means of flexible connections. Locking devices in type I connection system. Steel wire ropes or other means of flexible connections.

* Unless otherwise specified the certification standard is the rules

6 Testing 6.1 Testing during newbuilding 6.1.1 Class notations which require additional testing during newbuilding are given below: — — — — — — — —

Crane vessel (given in Sec.2 [1.4]) Semi-submersible heavy transport vessel (given in Sec.5 [1.4]) Diving support vessel (given in Sec.6 [1.4]) Seismic vessel (given in Sec.7 [5.1]) Well stimulation vessel (given in Sec.8 [3.1] and Sec.8 [3.2]) Fire fighter (given in Sec.9 [1.4]) Tug (given in Sec.11 [1.5]) Tug (Escort X(FS,t,v) (given in Sec.11 [6.8]).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 36

Part 5 Chapter 10 Section 1

Object

Symbols For symbols not defined in this section, see Sec.1 [3.1].

φ1 φ2

= heeling angle of equilibrium during crane operation, in deg

φ3 φC φF φR

= maximum (dynamic) heeling angle, in deg

= allowable limit heeling angle, equal to lesser of φF or φR, or the second intercept of the righting lever curve with the heeling lever curve, in deg = static heeling angle of equilibrium after loss of load, in deg = angle of down flooding,as defined in Pt.3 Ch.15, in deg = angle of vanishing stability, in deg.

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for lifting operations, and for that purpose are equipped with crane(s) or similar lifting appliance(s) and comprise heavy lift ships, crane ships, crane barges, floating cranes, or similar floating structures, with special attention on safety against capsizing.

1.2 Scope 1.2.1 These rules include requirements for hull strength, systems and equipment, stability and floatability applicable to crane vessels, including the crane(s) itself with respect to structural strength, safety equipment and functionality.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section may be given the class notation Crane vessel.

1.4 Testing requirements 1.4.1 Cranes After completed installation on board, functional testing of the crane shall be carried out as specified in DNVGL-ST-0378 Standard for offshore and platform lifting appliances.

2 Hull 2.1 General 2.1.1 The hull structural strength is in general to be as required for the main class taking into account necessary strengthening for supporting the crane during operation and in parked position at sea.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 37

Part 5 Chapter 10 Section 2

SECTION 2 CRANE VESSEL

3.1 Crane with substructure 3.1.1 The crane shall be delivered with the Society's certificates in compliance with DNVGL-ST-0378 Standard for offshore and platform lifting appliances. In agreement with the Society the crane may be certified based on other internationally recognised standards. Cranes certified by other societies may be accepted based on special consideration. 3.1.2 Devices for locking the crane in parked position at sea will be specially considered taking into account environmental load conditions as indicated for the main class of the vessel.

4 Stability 4.1 Application 4.1.1 General All loading conditions used in the lifting operation shall be in compliance with criteria specified in this section. In general, it is assumed that operations for heavy cargo transfer are carried out at zero speed over ground. The crane or lifting appliance itself shall be certified according to the Society's document DNVGL-ST-0378 Standard for offshore and platform lifting appliances. Alternative standards which provide an equivalent safety standard to this section may be applied, subject to prior consent by the Society. 4.1.2 Applicable stability criteria The intact and damage stability criteria applicable to the ship shall be complied with at all times including when the crane is in use, except for the conditions with operational and or environmental limitations as described in [4.4.1], [4.4.2] and [4.4.3]. This includes the main class requirements in Pt.3 Ch.15, statutory intact and damage stability requirements and voluntary class notations when applicable. The accidental load drop criterion in [4.3] shall be applied in all cases when counter ballasting is utilised. For lifting conditions carried out within clearly defined limitations as set forth by [4.4.1], [4.4.2] and [4.4.3], the alternative intact and damage stability criteria as set forth in [4.4.4] and [4.5] may be applied, subject to prior consent by the Society. In general the limiting wind speed shall be the same as applied for the approval of the loading gear according to the Society's document DNVGL-ST-0378 Standard for offshore and platform lifting appliances. Environmental and operational limitations shall be stated in the stability manual/operational manual. General criteria according to [4.2] shall be complied with at all times. In case hatch covers/stern ramps/side doors/ etc. are open during cargo transfer, the respective flooding points shall be considered as unprotected openings for all criteria. Additionally it has to be ensured that the centre of gravity of any heavy item, e.g. hatch covers, crane beam, stability pontoons, etc. are corrected for the actual position. When calculating stability, transverse centres of gravity shall be considered. To calculate the vessel’s vertical and lateral center of gravity during lifting operation, consider the suspension point at the crane top to be the center of gravity of the lifted load.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 38

Part 5 Chapter 10 Section 2

3 Systems and equipment

— Optionally maximum crane heeling moment as a function of crane boom direction as well as the corresponding counter ballast moment, if used, at each draught as a function of the vertical centre of gravity. — Loading conditions at typical (maximum, minimum and intermediate) draught(s) with maximum permissible crane load. The righting lever (GZ) curves before and after the load drop shall be presented for each loading condition where applicable. — Limitations on crane operation, including permissible heeling angles. — Instructions related to normal crane operation, including those for use of counter ballast. — Instructions such as ballasting/de-ballasting procedures to righting the vessel following an accidental load drop and/or damage if applicable.

4.2 General intact stability criteria for heavy lift operations 4.2.1 The following criteria to be complied with during lifting: — The heeling angle of equilibrium, φ1, during lifting operation shall not be greater than the maximum static heeling angle for which the lifting device is designed and which has been considered in the approval of the loading gear. — During lifting operations in sheltered waters, the minimum distance between the water level and the highest deck enclosing the watertight hull, i.e. normally the weather deck but no non-watertight openings below this deck, taking into account trim and heel at any position of the vessel shall not be less than 0.50 m. During lifting operations at sea, the residual freeboard shall not be less than the greater of 1.00 m or 75% of the highest significant wave height, HS in m, encountered during the operation. — If a stability pontoon* is used, the residual freeboard of the pontoon as well as the draft of the pontoon shall be not less than 0.60 m. The benefit of a stability pontoon shall only be used during lifting operations in calm water conditions. * A stability pontoon is a pontoon attached to the hull only during heavy lift operations for the purpose of increasing stability.

4.3 Intact stability for sudden loss of hook load 4.3.1 General If counter ballasting measures are used to carry out the lifting operation, such as transfer of ballast water and/or fuel, or other measures, sudden accidental loss of hook load due to failure of the lifting gear shall be considered. Such loss will cause the ship to immediately roll away from the side of the lift. If cargo hatch covers are open during such an operation, these hatch covers shall be considered as down flooding points. The safety of the lifting operation shall be demonstrated by either complying with a simplified criterion based on the righting lever curve properties [4.3.2] or by performing a numerical time-domain simulation to assess the maximum dynamic heeling angle, φ3. The latter may be a simplified analysis of a one degree of freedom differential equation of motion [4.3.3] or a fully viscous RANSE-based CFD calculation [4.3.4]. For lifts outside sheltered waters, the method according to [4.3.2] shall be applied. 4.3.2 Simplified criterion based on righting lever curve properties After the load is lost, the ship will heel over from the working list, φ1, to the maximum (dynamic) list, φ3, before settling at the equilibrium list, φC. Referring to the righting lever curve after loss of hook load for such operations, see Figure 1, the following minimum stability criteria shall be complied with: The angle of static equilibrium φC after loss of crane load shall not be more than 15° from the upright or the angle of deck edge immersion whichever is the less. In sheltered waters an angle of static equilibrium of 20° is acceptable. Area A2 below the righting lever curve shall be at least equal to area A1 plus a 40% safety margin, i.e., A

2

≥ 1.4 A1

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 39

Part 5 Chapter 10 Section 2

4.1.3 Stability documentation The following additional documentation shall be included in the stability manual/operational manual:

A

2

≥ 1.15 A1

Area A1 is the area below the righting lever curve, in m-rad, measured from heeling angle φ1 to heeling angle φC. Area A2 is the area, in m-rad, below the righting lever curve measured from heeling angle φC to heeling angle φ2, see Figure 1.

Figure 1 Righting lever curves for sudden loss of hook load 4.3.3 Simplified roll motion analysis The dynamic heel angle after a sudden loss of hook load may be estimated by performing a simplified timedomain numerical simulation of the ship’s roll motion. With the ship at equilibrium, start the analysis by releasing the hook load, simulating a sudden failure of the lifting gear. To represent the roll motion as a onedegree-of-freedom system, numerically solve its motion equation: Iroll + I'rollφ'' + Bφ' + Cφ = 0 where:

Iroll

2

= mass roll moment of inertia of the ship in loading condition after loss of hook load, in kNm-s

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 40

Part 5 Chapter 10 Section 2

For operations in sheltered waters a safety margin of 15% is sufficient:

= added mass roll moment of inertia of the ship in loading condition after loss of hook load, in 2 kNm-s

φ'' φ' φ Β C(φ)φ

= roll acceleration, in deg/s

2

= roll velocity, in deg/s = roll motion, in deg = linearised roll damping coefficient = roll restoring moment, in kNm, as a function of roll angle = GZ (φ) ∆Lg

GZ(φ) ΔL

= righting arm as a function of roll angle after loss of hook load, in m = ship displacement after loss of hook load, in t.

The linearised roll damping coefficient can be taken as two percent of critical damping. If a stability pontoon is situated on the side of the vessel opposite the hook load, a damping coefficient of five percent may be applied. Higher damping coefficients are acceptable if respective results of roll decay tests or validated numerical calculations are provided. The righting moment curve shall not be linearised; that is, the actual GZ curve after loss of hook load as a function of roll angle has to be used. The influence of the stability pontoon shall be considered. The initial working list, φ1, shall be accounted for. The maximum list, φ3, which occurs during the roll motion, shall not exceed the smaller of φE with a safety margin of 3° or φR with a safety margin of 7°: φ3 < min (φF- 3°, φR- 7°) 4.3.4 Reynolds-averaged Navier-Stokes (RANS) simulation of roll motion The dynamic heel angle after sudden loss of hook load can also be assessed by carrying out non-linear numerical simulations using a RANS equations solver. The RANS simulations shll account for not only the ship’s hull and the stability pontoon, but also those parts of the superstructure that contribute to the righting moment. The predicted time-dependent dynamic behaviour of the floating ship after a sudden loss of hook load yields the maximum list, φ3, which shall not exceed the smaller of φF with a safety margin of 2° or φR with a safety margin of 7°: φ3 < min (φF- 2°, φR- 7°) An example of a RANS simulation is set out in DNVGL-CG-0157 Sec.2 Stability documentation for approval.

4.4 Alternative intact stability criteria during heavy crane lift 4.4.1 The criteria given in [4.4.4] may be applied in lieu of the intact stability criteria according to Pt.3 Ch.15 for the crane loading conditions when operational and environmental limitations are imposed. 4.4.2 The environmental limitation shall at least be specified as follows: — maximum wind speed (1 minute sustained at 10 m above sea level) — maximum significant wave height. 4.4.3 The operational limitations shall at least be specified as follows: — maximum duration of the lift (operation reference period) — limitations in vessel speed — limitations in traffic/traffic control.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 41

Part 5 Chapter 10 Section 2

I’roll

— the deck corner shall not be submerged — ARL ≥ 1.4 · AHL with the wind superimposed from the most unfavourable direction the area in accordance with Figure 2 The area under the righting lever curve in m-rad, ARL, extends from the heeling angle of equilibrium, φ1, to the heeling angle φ2. Angle φ2 is the angle of down flooding, φF, or the angle of vanishing stability, φR, or the second intercept of the righting lever curve with the heeling lever curve, whichever is lesser. — the area under the GZ curve measured from the equilibrium position φ1 and to the down flooding angle φF, or 20°, whichever is less shall be at least 0.03 m-rad.

Figure 2 Alternative intact criteria

AHL ARL

= area, in m-rad, below heeling arm curve due to wind forces (for wind speed see [4.4.2]) = area, in m-rad, below net righting lever GZ curve for the condition, corrected for crane heeling moment and for the righting moment provided by the counter ballast if applicable. Guidance note: Net righting lever implies that the calculation of the GZ curve includes the vessel’s true transverse centre of gravity as function of the angle of heel. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.5 Alternative damage stability criteria during heavy crane lift 4.5.1 The flooding scenario given in [4.5.2] and survival criteria given in [4.5.3] may be applied in lieu of the damage stability criteria according to Pt.3 Ch.15 and additional class notations for the crane loading conditions when operational and environmental limitations as listed in [4.4.2] and [4.4.3] are imposed. 4.5.2 Accidental flooding of any one compartment bounded by the shell or which contains pipe systems leading to the sea shall be investigated for the relevant loading conditions. In addition, column-stabilised crane units shall be able to withstand the flooding of any watertight compartment fully or partially below the waterline in question, which is a pump room or a room containing machinery with a sea water cooling system.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 42

Part 5 Chapter 10 Section 2

4.4.4 The following criteria shall be met when the crane load is at the most unfavourable position:

— — — —

the maximum angle of heel shall be less than 15°, or 17° in case deck edge is not immersed in sheltered waters an angle of heel of 20° is acceptable no immersion of openings through which progressive flooding may occur the area under the GZ-curve shall not be less than 0.015 m-rad.

Other concepts may be applied if deemed appropriate for the vessel, subject to prior consent by the Society.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 43

Part 5 Chapter 10 Section 2

4.5.3 In the flooded condition the following criteria shall be complied with:

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for laying cables on the sea bottom.

1.2 Scope 1.2.1 These rules include requirements for hull strength, systems and equipment applicable to cable laying vessels, including: — — — — —

hull structural details related to the cable laying operation equipment and installations for cable laying supporting structures for equipment applied in the cable laying operations equipment for anchoring and mooring related to the cable laying operations equipment for positioning during cable laying.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section may be given the class notation Cable laying vessel.

2 Hull 2.1 Hull structural strength The hull structural strength shall in general be as required for the main class taking into account necessary strengthening of supporting structures for equipment applied in the cable laying operations.

2.2 Special hull configuration For catamarans, semi-submersibles and other special hull configurations, the hull structural strength will be specially considered.

3 Equipment 3.1 Equipment for mooring and anchoring 3.1.1 The equipment for mooring and anchoring, i.e. anchors, chain cables windlass, mooring ropes, shall in general be as required for the main class. 3.1.2 For catamarans, semi-submersibles and other special hull configurations, the equipment will be specially considered. 3.1.3 Equipment for positioning during cable laying will be specially considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 44

Part 5 Chapter 10 Section 3

SECTION 3 CABLE LAYING VESSEL

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for laying pipelines on the sea bottom.

1.2 Scope 1.2.1 These rules include requirements for hull strength, systems and equipment applicable to pipe laying vessels, including: — — — — —

hull structural details related to the pipe laying operations supporting structures for equipment applied in the pipe laying operations equipment for anchoring and mooring equipment and installations for pipe laying equipment for positioning during pipe laying.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section may be given the class notation Pipe laying vessel.

2 Hull 2.1 Hull structural strength The hull structural strength shall be as required for the main class taking into account necessary strengthening of supporting structures for equipment applied in the pipe laying operations.

2.2 Special hull configuration For catamarans, semi-submersibles and other special hull configurations, the hull structural strength will be specially considered.

3 Equipment 3.1 Equipment for mooring and anchoring 3.1.1 The equipment for mooring and anchoring, i.e. anchors, chain cables, windlass, mooring ropes, shall in general be as required for the main class. 3.1.2 For catamarans, semi-submersibles and other special hull configurations, the equipment will be specially considered. 3.1.3 Equipment for positioning during pipe laying will be specially considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 45

Part 5 Chapter 10 Section 4

SECTION 4 PIPE LAYING VESSEL

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for loading or unloading of deck cargo by submerging the cargo deck through ballast operations.

1.2 Scope 1.2.1 These rules include requirements for hull strength, systems and equipment, stability and load line, fire safety and lifesaving, navigation and communication applicable to semi-submersible heavy transport vessels.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section will be assigned the mandatory ship type notation Semi-submersible heavy transport vessel. The additional notation Strengthened(DK) is mandatory for vessels assigned the notation Semisubmersible heavy transport vessel.

1.4 Testing requirements 1.4.1 Sea trial A sea trial including submersion to maximum submerged draft and function testing of all equipment related to submersion shall be performed before final certificates are issued.

2 Hull 2.1 Hull girder strength 2.1.1 In transit condition the hull girder strength shall be evaluated according to Pt.3. 2.1.2 The strength during temporarily submerged condition shall be evaluated using acceptance criteria AC-II and with permissible stresses as given in Pt.3 Ch.5 Sec.3. Reduced dynamic hull girder loads may be applied in combination with still water hull girder loads to evaluate the hull girder strength. The dynamic hull girder loads given in Pt.3 Ch.4 Sec.4 [3] may be reduced by 50%. The dynamic load cases to be applied in the evaluation are HSM-1, HSM-2, FSM-1 and FSM-2. 2.1.3 In aft-loading/aft-unloading conditions (non-submerged condition), the hull girder strength may be evaluated applying same hull girder loads as given in [2.1.2] using acceptance criteria AC-II and with permissible stresses as given in Pt.3 Ch.5 Sec.3, providing that: 1) 2) 3)

the vessel is moored to the quay the operation is carried out in conditions with a significant wave height equal to or less than 0.5 m the hull girder loads are closely monitored throughout the loading/unloading sequence.

In such cases the method used for monitoring the loads will be subject to special consideration.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 46

Part 5 Chapter 10 Section 5

SECTION 5 SEMI-SUBMERSIBLE HEAVY TRANSPORT VESSEL

2.2 Local strength 2.2.1 In transit condition the local strength shall be evaluated according to Pt.3. 2.2.2 External hull boundaries and sea chest boundaries shall be able to withstand the sea pressure at temporarily submerged draught for acceptance criteria AC-II and with permissible stresses as given in Pt.3 Ch.6 Sec.4 and Pt.3 Ch.6 Sec.5, for design load set SEA-1. Reduced dynamic hull girder loads may be applied in combination with still water hull girder loads to evaluate the local strength. The dynamic hull girder loads given in Pt.3 Ch.4 Sec.4 [3] and the dynamic sea pressure given in Pt.3 Ch.4 Sec.4 [3] may be reduced by 50%. The dynamic load cases to be applied in the evaluation are HSM-1, HSM-2, FSM-1 and FSM-2. 2.2.3 The design pressure for internal watertight bulkheads, including doors, hatches, pipe penetrations and other piercings, shall be based on the deepest equilibrium waterline in damaged transit or damaged submerged condition, as applicable, depending on relevant damage scenario, for acceptance criteria AC-III and design load set FD-1 as given in Pt.3 Ch.6 Sec.2 Table 1. Permissible stresses as given in Pt.3 Ch.6 Sec.4 and Pt.3 Ch.6 Sec.5. Damage stability requirements in transit and submerged conditions are given in [4.1] and [4.3], respectively. Flooding scenarios related to access openings in submerged conditions, refer [5.4.5], shall also be taken into account. 2.2.4 Bolted connections between buoyancy towers and hull are subject to special consideration.

2.3 Integrated high-pressure tanks 2.3.1 Ballast tanks emptied by means of air overpressure are subject to special consideration. The strength of such tanks shall minimum satisfy the static acceptance criteria AC-I according to the design load sets given in Pt.3 Ch.6 Sec.2 Table 1 with corresponding permissible stresses as given in Pt.3 Ch.6 Sec.4 and Pt.3 Ch.6 Sec.5, with full tank and maximum overpressure, e.g. de-ballasting condition. The air overpressure shall 2 not be taken greater than 70 kN/m . For primary supporting members net loading, internal minus external pressure, shall be applied, see Pt.3 Ch.6 Sec.2 [2]. Guidance note: In designs where air overpressure is applied for emptying integrated ballast tanks, exemptions from the rules for pressure 2

vessels in Pt.4 Ch.7 may be granted on a case-by-case basis when the air overpressure is greater than 70 kN/m , provided that satisfactory alternative safety measures are presented. Examples of such safety measures are increased safety margin by lowering the allowable stress levels, installation of cofferdams, reduced size of ballast tanks, pressure monitoring systems, increased NDT during construction, and more thorough inspections in the operation phase. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.4 Primary supporting members 2.4.1 Direct strength analysis Cargo hold FE analysis are normally required to evaluate primary members in midship region. Primary supporting members outside of midship region shall be evaluated in accordance with Pt.3 Ch.6 Sec.6.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 47

Part 5 Chapter 10 Section 5

2.1.4 Due to the low depth of the hull girder, special attention should be paid to the requirement to moment of inertia given in Pt.3 Ch.5 Sec.2 [1.5]. This requirement shall be satisfied over a minimum of 0.25 L in the midship area.

— — — —

permissible local and distributed loads as specified in the loading manual transit condition considering extreme combination of deck loads and tank loads for AC-II operational including submerged conditions for AC-II with reduced dynamic loads de-ballasting condition, e.g. full tank with maximum overpressure, for AC-I.

2.4.3 Buckling check of plate panels The normal stresses and shear stress taken from strength assessment to be applied for buckling capacity calculation of deck plate panels shall be corrected as given in Pt.3 Ch.8 and DNVGL-CG-0128 Buckling.

2.5 Fatigue strength 2.5.1 For vessels with L ≥ 150 m, all longitudinal strength members on external shell and deck shall be verified for compliance with the prescriptive fatigue strength requirements in Pt.3 Ch.9. 2.5.2 Additional fatigue analysis may be required for details considered prone to failure or considered particular critical for watertight integrity.

3 Systems and equipment 3.1 Additional anchors 3.1.1 Anchors and associated equipment in excess of that required in Pt.3 Ch.11 Sec.1 Table 1 need not be certified.

3.2 Watertight seals for propeller axle and rudder stock 3.2.1 Watertight seal on propeller axle and rudder stock shall be approved for the maximum submerged draught.

4 Stability 4.1 Stability requirements in transit condition 4.1.1 The intact stability requirements of The International Code on Intact Stability (2008 IS Code) Part A, Ch. 2.2 and 2.3 apply. The windage area in loading conditions shall include deck cargo. 4.1.2 If the vessel's characteristics render compliance with The International Code on Intact Stability (2008 IS Code) Part A, Ch. 2.2 impracticable, then the criteria of Part B, Ch.2.4.5 may be used. 4.1.3 For intact stability the buoyancy provided by a part of large deck cargo such as semi-submersible units, jack-up units, barges or ships may be taken into account, provided that the securing arrangement is separately approved. The watertight integrity of the cargo shall be defined and taken into account in the calculations. 4.1.4 The damage stability standard shall be in accordance with SOLAS Ch.II-1 or ICLL 1966 Reg.27, including IACS UI LL65, as applicable.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 48

Part 5 Chapter 10 Section 5

2.4.2 Loading conditions The loading conditions need to be determined case by case to cover the most demanding of static, static + dynamic and accidental flooding conditions including:

B-60 freeboard requires one-compartment damage, while B-100 requires two-compartment damage in accordance with Reg.27 of the ICLL 1966. The calculations shall be carried out assuming the damaged tanks empty and for representative loads, such as a semi-submersible unit and a jack-up unit, as far as applicable. Damage extent shall be taken according to ICLL Reg. 27. The buoyancy of watertight volumes of the deck cargo not located within the damage extent for each damage case may be taken into account. In all cases, transverse penetration shall be taken from the ship’s side. 4.1.6 Ships with ordinary B freeboard If, in addition to the SOLAS limit curves, it is desired to take the buoyancy of the deck cargo into account, calculations as for ICLL Reg. 27 corresponding to B-60 damage may be considered equivalent, i.e. same approach as the case of ships with reduced freeboard. Guidance note: As there are no international rules or interpretations regarding whether the buoyancy of deck cargo may be taken into account in order to make these operations feasible, the flag state must be approached for acceptance of the application of the requirements given in [4.1.3] and [4.1.5] for statutory purposes. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.2 Intact stability criteria in temporarily submerged conditions 4.2.1 All loading and unloading sequences shall have acceptable stability. The buoyancy provided by a part of large deck cargo such as semi-submersible units, jack-up units, barges or ships may be taken into account, provided that proper environmental limitations have been defined. 4.2.2 The GM at equilibrium shall not be less than 0.3 m. The positive range of the GZ curve shall be minimum 15° in conjunction with a height of not less than 0.1 m within this range. The maximum righting arm shall occur at an angle of heel not less than 7°. Unprotected openings shall not be immersed within this range. It may be required to calculate the stability about additional axis to determine the most onerous result. 4.2.3 Whenever free liquid surface exists in a tank, the effect shall be considered. The calculations shall account for the real filling of the tanks, i.e. in particular the location of air pipes needs to be taken into account. If the complete filling of the tanks is dependent on certain trim or heel during the submerging sequence this shall be clearly stated in the stability manual.

4.3 Damage stability in temporarily submerged conditions 4.3.1 The risks of accidental flooding of any one compartment on the ship shall be considered. Damage to be considered is that which might occur following an uncontrolled movement of the deck cargo during loading or off-loading leading to puncture of exposed surfaces. This study shall cover all relevant phases of the loading/ off-loading sequence as required by [4.2.1]. 4.3.2 Accidental flooding of watertight compartment described in [5.4.4] shall be considered in addition if this would result in a more severe condition. 4.3.3 The permeability μ of a damaged compartment shall be assumed to be 0.95 except for full ballast tanks, where μ = 0. For machinery spaces, μ = 0.85. 4.3.4 In the final stage of flooding after damage, the positive range of the GZ curve shall be minimum 7° in conjunction with a height of not less than 0.05 m within this range. Unprotected openings shall not be immersed within this range unless the space concerned is assumed to be flooded. The angle of heel after flooding shall not exceed 15°. The final waterline after flooding shall be below the lower edge of any weathertight opening through which progressive flooding may take place unless the space concerned is

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 49

Part 5 Chapter 10 Section 5

4.1.5 Ships with B-60 or B-100 freeboard

4.3.5 The stability at intermediate stages of flooding after damage shall not be significantly less than in the final stage. 4.3.6 The flooding of any damaged compartment shall not render vital safety functions inoperative. 4.3.7 For the purpose of damage stability calculations, a damage extent of 5 m horizontally along the surface shall be assumed for all exposed surfaces except the cargo deck. Watertight bulkheads may be considered to remain intact provided that the distance between adjacent bulkheads exceeds 5 m. The damage penetration into the structure shall be assumed to be equal to 0.76 m and the vertical extent of damage is assumed to be from the cargo deck or its horizontal extension upwards without limit. For the cargo deck a damage extent of 5 × 5 m shall be assumed. Watertight bulkheads may be considered to remain intact provided that the distance between adjacent bulkheads exceeds 5 m. The damage penetration into the cargo deck shall be assumed to be equal to 0.76 m.

5 Openings and closing appliances 5.1 Freeboard assignment transit draught 5.1.1 Freeboard will be calculated and assigned according to ICLL 1966 and standard procedures. Compliance with requirements for weathertight and watertight closing appliances shall be documented with a freeboard plan.

5.2 Temporarily submerged conditions 5.2.1 Requirements for reserve buoyancy and water- and weathertight integrity given in [5.3] and [5.4] shall be complied with in the maximum submerged draught condition. Guidance note: International load line exemption certificate Independent of class approval, an exemption from ICLL 1966, Article 12 Submersion will have to be applied for as the load line mark will be submerged during cargo operations. This exemption may only be granted by the flag administration and should be based on an application from the owner. The flag administration will normally require the Society to give their comments to the application. The Society will give recommendation/comments based on the compliance with the requirements in this section. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.3 Reserve buoyancy 5.3.1 The ratio of reserve buoyancy shall not be less than: — 4.5% for the vessel — 1.5% for the forward and aft end buoyancy structures considered separately. 5.3.2 The reserve buoyancy requirements in [5.3.1] shall be documented by a calculation according to the principles given in a) to d). a)

Ratio of reserve buoyancy is the reserve buoyancy divided by the volume displacement of the vessel at maximum submerged draught with no trim.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 50

Part 5 Chapter 10 Section 5

assumed to be flooded. It may be required to calculate the stability about additional axis to determine the most onerous result.

Reserve buoyancy is defined as the volume providing buoyancy, positioned above the waterline with no trim at maximum submerged draught. In the calculation of the total reserve buoyancy for the vessel, no buoyancy shall be assumed above the lowest of the zero trim waterlines corresponding to: — the position of the lowest opening which can not be closed and secured to prevent water from entering the buoyant volume — the uppermost point of the deck limiting the buoyancy structure forward — the uppermost point of the deck limiting the buoyancy structure aft.

c)

Calculations for end structures considered separately need only take account of openings and decks in the end under consideration. Trim shall be taken into account if it is consistent with practice to operate the vessel with trim and the maximum draught at the perpendicular is larger than the mean maximum submerged draught. Reserve buoyancy is then defined as the volume providing buoyancy for the end under consideration, above the waterline with no trim at maximum perpendicular draught.

d)

Openings which can not be closed and secured to prevent water from entering the buoyant volume shall be considered as down flooding points in the reserve buoyancy calculation. These openings shall include all air pipes, but need not include weathertight doors, hatches, ventilators, side scuttles and small windows with deadlights. This is provided that the relevant opening will be closed and secured during submerged stages, and that the closing appliance has been found to be adequate and of at least the same strength as the bulkhead or deck where it is fitted.

The calculation shall be submitted as a separate document and not be part of the stability documentation. 5.3.3 As an alternative to the requirements in [5.3.1], the reserve buoyancy may be evaluated based on real intact and flooded scenarios with the intact vessel at maximum submerged draught, including trim when relevant. In intact scenarios, ship movements shall be evaluated to determine the risk of submergence of decks limiting buoyancy structures. In flooded scenarios, the freeboard to a deck limiting a buoyancy structure shall not be less than 1 m. Guidance note: Intact scenarios should consider ship movements in defined worst operating sea condition(s) and as the result of forces transferred from cargo. Flooded scenarios should at least cover the effect of filling additional tank space by mistake and the effect of tanks and dry spaces being flooded due to valve failure. The possibility of spaces being flooded progressively should be taken into account where necessary. Partial flooding stages should be considered where this may give a more severe waterline. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.4 Requirements for water- and weathertight integrity 5.4.1 All openings below the first deck above the maximum submerged draught shall be arranged with watertight closing appliances. 5.4.2 Access openings which are submerged at the maximum submerged draught shall be protected by two watertight doors or hatches in series. A leakage detection device shall be provided in the compartment between the two doors or hatches. Drainage of this compartment to bilges controlled by a readily accessible screw-down valve shall be arranged. 5.4.3 A watertight closing appliance shall be provided for any internal opening leading to the compartment required by [5.4.2]. 5.4.4 The effect of flooding the watertight compartment required by [5.4.2] shall be investigated in the stability calculations for all stages where the outer door or hatch is submerged. 5.4.5 Bulkheads bounding the compartment required by [5.4.2] shall be of sufficient strength to withstand the water pressure that could occur after flooding. Doors and hatches shall be approved and pressure tested.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 51

Part 5 Chapter 10 Section 5

b)

5.4.7 Scuppers shall be of substantial thickness below the first deck above the maximum submerged draught.

5.5 Miscellaneous requirements 5.5.1 On-board instruction manuals and check lists containing operating procedures for submerging shall list the closing appliances which have to be closed before operation commences. Examples are watertight doors and hatches, closing appliances as given in [5.4.2] and [5.4.3], and closing valves in sanitary discharges. Signboards shall be fitted at the relevant closing appliance. 5.5.2 Guard rails shall be arranged so that they do not interfere with cargo operations. Removable guard rails with steel wire rope may be acceptable, provided that the arrangement is according to ICLL 1966 and scantlings are found sufficient. Wires should have steel cores of not less than 10 mm in diameter and be plastic coated. 5.5.3 In order to provide access to the ends of the vessel when deck cargo covers the whole breadth of the vessel, an under-deck passage way in compliance with Pt.3 Ch.11 Sec.3 [3.2.2] item a) shall be provided.

6 Fire safety and lifesaving appliances 6.1 Fire extinguishing equipment 6.1.1 The cargo deck shall be protected by fixed fire-fighting equipment consisting of water monitors or fire hydrants with hoses, or a combination thereof. 6.1.2 If water monitors are selected in lieu of fire hydrants, then the monitors shall be capable of covering the cargo deck area and may be positioned fore and/or aft of the cargo area, as applicable. The fire monitors shall also comply with [6.1.1] to [6.1.6]. 6.1.3 The main control station for the system shall be suitably located outside the cargo deck area, adjacent to the accommodation spaces and readily accessible and operable in the event of fire in the areas protected. For monitors arranged at the end of the cargo area opposite to the accommodation spaces, remote control of the monitor(s) from the bridge will be required. Alternatively, these monitors shall be of oscillating type capable of sweeping the protected area. 6.1.4 The protected area shall be within 75% of the water monitor throw in still air conditions taking into account the distance from the monitor to the farthest extremity of the protected area forward of that monitor. 6.1.5 The capacity of each monitor shall not be less than 1250 litres/minute. The additional water supply to the monitors shall be based on one monitor operated at a time, and shall be in addition to the requirements given in SOLAS Reg. II-2/10.2.2.4. 6.1.6 Fixed arrangement for possible dispersion of the monitor water jet shall be delivered as part of each monitor. 6.1.7 Fire hydrants arranged with two hydrants at both port and starboard side just aft and forward of the cargo area, with sufficient number of hoses to reach the entire cargo area with two jets of water from these hydrants, will be accepted as equivalent to the position of hydrants required by SOLAS Reg. II-2/10.2.1.5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 52

Part 5 Chapter 10 Section 5

5.4.6 All openings between the first and second deck above the maximum submerged draught shall comply with ICLL 1966 position 2 requirements for weathertight closing.

6.2 Escape ways 6.2.1 The under-deck passage way required by [5.5.3] shall not be used as an escape way in submerged conditions. 6.2.2 If buoyancy towers are manned during cargo handling operations, then these shall be provided with escape ways to the life saving appliances. Such arrangement will be subject to special consideration, depending on the design.

6.3 Location of survival craft 6.3.1 If buoyancy towers are manned during cargo handling operations, then these shall be fitted with life saving appliances, such as life buoys or rafts. The type and arrangement of such appliances will be subject to special consideration, depending on the design. Guidance note: Survival craft forward of wide deck cargo should be specially considered by the body approving the life saving arrangement, to ensure that they are positioned in a way such as to avoid damage from the cargo. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7 Navigation and communication 7.1 Navigation 7.1.1 In cases where the cargo is partially blocking the view from the bridge, a secondary look-out point (crows nest) shall be arranged. Guidance note: Unless the secondary look-out point is fully duplicated, manning of both wheel house and look-out point will normally be required by the flag administration during transport. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Equipment in the secondary look-out point shall at least include: — conning position with un-obscured view to the sea surface looking forward over an arc of 225° (see SOLAS Reg. V/22) — a gyro bearing repeater — rudder, propeller, thrust, pitch and operational mode indicators — external communication system, one VHF — internal communication system for communication with main bridge. Guidance note: Acceptance of alternative solutions may be granted by the flag administration. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 53

Part 5 Chapter 10 Section 5

For SOLAS convention ships, this equivalent arrangement is subject to acceptance by the flag administration. These will ensure flexibility during fire-fighting operations, and will cover areas screened from the monitors.

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for diving support services with particular focus on the robust design of the diving equipment and systems, and the ability to maintain position safely during diving operations through built in redundancy.

1.2 Scope 1.2.1 These rules include requirements for hull strength, diving systems and diving equipment applicable to diving support vessels.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section and arranged for support of diving operations applying rope and/or umbilical connection between the submerged bell and the diving support vessel may be given the class notation: — Diving support vessel(Surface) or — Diving support vessel(SAT) as applicable. The above class notations require that the diving support vessel is equipped with a diving system classified by the Society in compliance with DNV-DSS-105 Rules for Classification of Diving Systems. Table 1 Class notations Diving support vessel(Surface)

Class Restrictions Provisions

d

max

≤ 60 msw *

Diving support vessel(SAT)

)

None, except those imposed by the rule requirements

TOP ≤ 8 hours Open or closed bell allowed No HES required

Closed bell Dedicated HES required

)

* msw = metres sea water, dmax = maximum operating depth TOP = Time Of Pressurization HES = Hyperbaric Evacuation System Guidance note: These requirements ensure that those given in the IMO Code of Safety for diving systems adopted 23 November 1995 as res. A.831(19), are met. Requirements for surveying of diving systems in service are given Pt.7 Ch.1 Sec.6. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3.2 Requirements which do not specifically refer to Diving support vessel(Surface) or Diving support vessel(SAT) diving systems, or which are called minimum requirements in the rules, apply to all systems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 54

Part 5 Chapter 10 Section 6

SECTION 6 DIVING SUPPORT VESSELS

1.3.4 Operational limitations and conditions of use for which the diving system is intended. 1.3.5 Codes and standards with which the diving system has been found to comply. 1.3.6 A diving support vessel class notation will be issued in the class certificate for the vessel as a formal statement confirming that the diving system installation has been completed in accordance with specified requirements.

1.4 Survey and testing requirements 1.4.1 General When a diving system classed by the Society has been installed on: a) b) c)

a ship or a mobile offshore that is not covered by the Society's classification, or on a fixed offshore installation, or on an onshore site,

an arrangement will be agreed for periodical surveys in order to ensure proper maintenance of the diving system. Corresponding documents will be issued. The Society will require that the ship or mobile offshore platform is classified in a recognized classification society. The main particulars of the diving system will be entered in the register of vessels classed with the Society. 1.4.2 When a diving system is built and installed according to these rules, the following shall be satisfied: a) b) c) d) e) f)

The design and scantlings comply with the approved plans and the requirements in these rules and other specified recognized standards, codes, and national regulations. That the materials and components are certified according to these rules and the terms of delivery. That the work is carried out in accordance with the specified fabrication tolerances and required quality of welds. That piping systems conducting gas in life support systems are cleaned in accordance with an approved cleaning procedure. That gas cylinders are clean and sealed. That all required tests are carried out.

1.4.3 The general scope for survey of diving systems is described in DNV-RP-E401 Survey of Diving Systems, but shall be documented in a system specific survey planning document. 1.4.4 The inspection shall be carried out during the assembly and during installation. The extent and method of examination shall be agreed prior to the work being carried out. 1.4.5 Additional tests may, however, be required. 1.4.6 Test plan for testing after completed installation A comprehensive test plan for the fully installed system shall be submitted for approval. This plan shall include testing details for, as a minimum: a) b) c) d) e)

pressure tests purity tests gas leakage tests handling systems life support systems safety systems

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 55

Part 5 Chapter 10 Section 6

1.3.3 Diving system description and item number, in a data sheet (Form 20.201a) accompanying the certificates and reports.

electrical systems instrumentation environmental control systems after installation onboard sea trials.

1.5 Classification of diving systems 1.5.1 Maintenance of class notation During the operations phase, verification in order to maintain the class notation is outlined in Pt.7 Ch.1 Sec.6. Some certificates having a period of validity will have a specific area to be signed annually by the Society showing satisfactory completion of the annual assessments required so as to continue the certificate’s validity. These certificates will become invalid if the signatures are not present. For diving systems this applies to the statutory certificate IMO Diving System Safety Certificate and certificates of conformance issued to modules. 1.5.2 Assumptions for classification Classification is based on the assumption given in the rules Pt.1 Ch.1. 1.5.3 Verification of compliance during operation Verification of compliance during operation is carried out by periodical or occasional surveys, of the system in sufficient detail to ensure that the specified requirements of the system continue to be achieved. (See Pt.7 Ch.1) 1.5.4 Obligations of the parties to the classification The companies responsible for the certification and classification of the diving system and diving support vessel shall ensure compliance with the applicable rules, regulations and normative references. Compliance shall be demonstrated through verifiable evidence. Further obligations are given in the rules Pt.1 Ch.1. 1.5.5 Class entry of diving systems Class entry procedures are, in general terms, given in Pt.1 Ch.1. For existing diving systems classified by another classification society, evidence of previous design approval will be required. Such evidence shall include drawings of the arrangement and details bearing the approval stamp, or specifically covered by an approval letter. In addition, for components requiring certification, the corresponding certificates shall be available along with maintenance records. After review of the evidence and examination and testing in accordance with relevant parts of DNVGL-OSE402 Ch.2, the system may be registered under class notation with the Society. 1.5.6 Verbal forms and definitions For verbal forms and definitions, see Pt.1 Ch.1 Sec.1 DNVGL-RU-OU-0375 and DNVGL-OS-E402.

1.6 Quality management 1.6.1 General A quality plan shall be submitted for the diving system installation, which shall be approved. Reference should be made to ISO 10005:2005 - Guidelines for Quality Plans.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 56

Part 5 Chapter 10 Section 6

f) g) h) i)

1.7.1 Concept development Data and description of system development and general arrangement of the diving system installation shall be established and submitted to the Society for design approval preview. The data and description shall include the following, as applicable: a) b) c) d) e) f) g) h) i) j) k)

safety objective locations, supporting structures and interface conditions diving system description with general arrangement and system limits functional requirements including system development restrictions, e.g., significant wave height, hazardous areas, fire protection installation, repair and replacement of system elements and fittings project plans and schedule, including planned period for installation design life including specification for start of design life, e.g. final commissioning, installation data of contained liquids and gases capacity and sizing data geometrical restrictions such as specifications of diameter, requirement for fittings, valves, flanges and the use of flexible hoses second and third party activities.

1.7.2 Plan for installation and operation The design and planning for a diving system installation shall cover all development phases including manufacture, installation and operation. Detailed plans, drawings and procedures shall be prepared for all installation activities. The following shall as a minimum be covered: a) b) c) d) e) f) g) h) i) j) k)

diving system location overview (planned or existing) other vessel (or fixed location) functions and operations list of diving system installation activities alignment rectification installation of foundation structures preparation of outer area to proceed with installation of interconnecting services (e.g. pipes, cables, etc.) completing welding, painting, general cleaning. installation of interconnecting services installation of protective devices hook-up to support systems as-built survey final testing and preparation for operation.

1.8 Marking and signboards 1.8.1 General Each main component of the diving system installation shall be stamped with an official number or other distinctive identification which shall be given on the certificate. Labels (nameplates) of flame retardant material bearing clear and indelible markings shall be placed so that all equipment necessary for operation (valves, detachable connections, switches, warning lights etc.) can be easily identified. The labels shall be permanently fixed. 1.8.2 Pressure vessels, gas containers and piping systems Pressure vessels, gas containers and piping systems shall be consistently colour coded.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 57

Part 5 Chapter 10 Section 6

1.7 Pre-classification

1.8.3 Handling system The handling system shall, in an easily visible place, be fitted with a nameplate giving the following particulars: a) b) c) d) e)

identification number static test load functional test load working weight surveyor's mark and identification.

The above loads shall be specified for each transportation system involved.

1.9 Design philosophy and premises 1.9.1 Location and arrangement of the diving system onboard General The diving system shall be so located that diving operations shall not be affected by propellers, thrusters or anchors. Guidance note: Some national regulations will limit the length of the umbilical so that the diver, or his umbilical, cannot be drawn into the propellers or thrusters. Requirements for the use of wet-bell may also apply in some regions. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Where, due to the requirements of diving operations, systems are sited in hazardous areas, the electrical equipment should comply with the requirements for such equipment in hazardous areas. Diving systems should not be permitted in hazardous areas designated as zone 0. The above implies that the location of a Diving support vessel(SAT) diving system on a ship, mobile unit or fixed offshore structure, or land site, shall be in a safe area with respect to explosive gas-air mix. Safe areas are in this context are areas which are not defined as hazardous zones in International Electro Technical Commission's Publication No.79-10, and IMO (MODU) code, chapter 6, as follows: a) b) c)

Zone 0: in which an explosive gas-air mixture is continuously present or present for long periods. Zone I: in which an explosive gas-air mixture is likely to occur in normal operation. Zone 2: in which an explosive gas-air mixture is not likely to occur, and if it occurs it will only exist for a short time.

Upon special consideration and agreement in each case, however, Diving support vessel(SAT) diving systems may be located in spaces which normally would be defined as zone 2. When any part of the diving system is sited on deck, particular consideration should be given to providing reasonable protection from the sea, icing or any damage which may result from other activities on board the ship or floating structure. This includes the hyperbaric evacuation system (HES). Diving systems situated on open decks shall not be located in the vicinity of ventilation openings from machinery spaces, exhausts or ventilation outlets from galley. Guidance note: Dive systems should not be exposed to temperatures outside the range it has been certified for. This shall be specially considered when the diving system is not positioned in a temperature controlled environment (e.g. open deck). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

The diving system should not be installed close to sources of noise that may expose divers to harmful noise. Personnel in the in the outer area shall have the possibility to communicate in an acceptable way where 75 dB(A) should be the noise limit. If the diving support vessel does not carry the class notation COMF(Vcrn), the diver’s accommodation area (inner area) shall be subject to the relevant vibration and noise

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 58

Part 5 Chapter 10 Section 6

There shall be a chart posted in the control room explaining the colour code.

The diving system and breathing gas storage facilities shall not be sited in machinery spaces if the machinery is not associated with the diving system. 1.9.2 External and internal environmental conditions General Systems and components shall be designed for the environmental conditions expected at their installed location (on the diving support vessel or otherwise) and their geographic site of operation. Additional requirements for various systems and components may be given elsewhere in the rules. Consideration shall be taken to external environment in terms of toxic, e.g. H2S and hydro carbon gas. Where diving systems shall be operated in known geographical locations were such gases exist, contingencies shall be provided and operational response to mitigate exposed risk. The effects of environmental phenomena relevant for the particular location and operation in question shall be taken into account. Guidance note: Environmental phenomena that might impair proper functioning of the system or cause a reduction of the reliability and safety of the system shall be considered, (including fixed and land-based installations): —

temperature

—

wind, tide, waves, current

—

ice, earthquake, soil conditions

—

marine growth and fouling. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

External environmental conditions Design inclinations shall be according to Table 2. Table 2 Design inclinations Location

Roll

Permanent list

Pitch

Trim

+/-22.5°

+/-15°

+/- 10°

+/-5°

Chambers and other surface installations: On a ship On a mobile offshore unit

+/-15°

+/-15°

Range of ambient temperature: -10°C to 55°C, unless otherwise specified. For greater temperature ranges, temperature protection shall be provided. Humidity: 100%.

3

Atmosphere contaminated by salt (NaCl): Up to 1 mg salt per 1 m of air, at all relevant temperatures and humidity conditions. Corrosion In order to assess the need for corrosion control, including corrosion allowance and provision for inspection and monitoring, the following conditions shall be defined: a) b) c) d) e)

Maximum and average operating temperature and pressure profiles of the components, and expected variations during the design life. Expected content of dissolved salts in fluids, residual oxygen and active chlorine in sea water. Chemical additions and provisions for periodic cleaning. Provision for inspection of corrosion damage and expected capabilities of inspection tools, i.e. detection limits and sizing capabilities for relevant forms of corrosion damage. The possibility of wear and tear, galvanic effects and effects in still water pools shall be considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 59

Part 5 Chapter 10 Section 6

measurements applicable to the remaining accommodation. The noise limit 60 dB(A) shall not be exceeded, while 55 dB(A) is recommended.

Diving systems shall be operated in such a manner that they: a) b) c) d)

Fulfil the specified operational requirements. Fulfil the defined safety objective and have the required support capabilities during planned operational conditions. Have sufficient safety margin against accidental loads or unplanned operational conditions. Cater for the possibility of changes in the operating conditions and criteria during the lifetime of the system.

Any re-qualification deemed necessary due to changes in the design conditions, shall take place in accordance with provisions set out in each section of the rules. Parameters that could jeopardise the safety of the divers, and or violate the integrity of a diving system, shall be monitored and evaluated with a frequency that enables remedial actions to be carried out before personal harm is done or the system is damaged. Instrumentation may be required when visual inspection or simple measurements are not considered practical or reliable, and available design methods and previous experience are not sufficient for a reliable prediction of the performance of the system. The various pressures in a diving system shall not exceed the design pressures of the components during normal steady-state operation. Monitoring during operation Guidance note: As a minimum the monitoring and inspection frequency should be such that the diving system, and consequently the diving operation, shall not be endangered due to any realistic degradation or deterioration that may occur between two consecutive inspection intervals. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.10 Handling of diving systems not certified by the Society 1.10.1 General Diving systems classed with another class societies and carried onboard diving support vessels classed with the Society. Installed saturation diving systems and equipment carried onboard in excess of the minimum required for class shall either be maintained to applicable standards, or be removed or disconnected in such a way as to ensure that the installed system or equipment cannot be used. Applicable standards may be those of a recognized classification society which has rules for diving systems acceptable to the administration as stated in 2.1.4 of the IMO Code of Safety for Diving Systems, 1995 (Res. 831(19)). For surface oriented diving systems the following minimum requirements apply when in use: a) b)

All pressure components requiring certification shall be certified by a recognised authority Certified pressure components shall be tested according to schedules defined in these rules.

For diving systems classified by other classification societies, compliance shall be verified by the Society on a case by case basis. The following documents shall be submitted: a) b)

Diving system class certificate from the recognised classification society IMO Diving System Safety Certificate (DSSC), see IMO Code of Safety for diving systems adopted 23 November 1995 as res. A.831(19), as required by the vessel's maritime administration.

When a diving system classed by another classification society, is installed onboard a ship or mobile offshore unit classed by the Society, the diving system shall be designed, manufactured and maintained in class in accordance with the rules and the requirements of the class society in which the diving system is classed.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 60

Part 5 Chapter 10 Section 6

1.9.3 System design principles System integrity

When diving systems, classed by another recognised classification society, are installed on the Society's classed diving support vessels, procedures for verification of compliance will include the following scope involving each society according to their individual scope: a)

Classification of diving system: i) ii)

The classification society classifying the diving system, shall bring the entire diving system into class in accordance with their procedures, and issue all applicable certificates and reports. The classification certificate, and class status, issued by the diving system’s class society shall be presented to the attending surveyor. The Society will consider conditions of class (CC) issued to the diving system by the diving system’s class society, to determine if any of these affect the main class for the diving support vessel.

b)

Interoperability between diving system and diving support vessel: i)

The owners of the diving system shall ensure that the Society is informed of the various system interfaces affecting the diving support vessel before the diving system is installed onboard.

c)

The Society will verify supporting structures foundations pertaining to the diving support vessel in support of the diving system. Drawings and load calculations shall be submitted to the Society according to requirements given in Pt.3 Ch.11 Sec.2.

d)

The Society will verify that additional power supplied from the diving support vessel to the diving system do not adversely affect the main class on the diving support vessel.

e)

Statutory certification – when authorised by the maritime authorities: i)

The diving system’s class society will issue the Diving System Safety Certificate (DSSC) in compliance with the IMO Code of Safety for diving systemson behalf of the maritime authorities where the diving support vessel is registered. Compliance includes verification of the hyperbaric evacuation system against the guidelines referred to in chapter 3 of the IMO Code.

f)

The DSSC issued by the diving system’s class society shall be presented to the attending surveyor.

g)

The Society will consider all conditions of authority (CA) issued to the diving system, to determine if any of these affect the statutory certification for the diving support vessel.

h)

If authorised, the Society may verify that the diving operations are included in the ship’s management system in accordance with requirements in the ISM Code.

i)

The following documentation is required for information: i) all class and statutory certificates ii) current class status of the dive system iii) evidence of a review by the diving systems class society for installation on the vessel. Normally this should include stamped drawings, for info or approved as relevant iv) vessel GA with dive system arrangement v) block diagram of the dive system showing quantified vessel supplies and demarcation lines showing limit of dive system class vi) drawings of system foundations showing accelerations as installed and allowable deflections vii) details of intended area of operation including environmental conditions and contingency planning.

j)

The following documentation is required for approval: i) deck drawings showing supporting structure(s) ii) interface drawings for fresh, gray and black water, electrical and fire extinguishing systems iii) updated safety plan including escape routes for critical dive personnel involved in launching or manning the HES.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 61

Part 5 Chapter 10 Section 6

Periodical surveys shall be carried out by that class society. Statutory requirements and periodical surveys shall be carried out by a recognised organisation or by the flag administration itself.

2 Hull 2.1 Supporting structure for diving system equipment 2.1.1 General Provisions shall be made to ensure that the diving system installations and auxiliary equipment are securely fastened to the ship or floating structure and that adjacent equipment is similarly secured. Consideration shall be given to the relative movement between the components of the system. In addition, the fastening arrangements shall be able to meet any required survival conditions of the ship or floating structure. When the diving system is taken onboard and mobilised for use, the equipment related to the diving system shall be permanently attached to the hull structure, e.g. by welding, bolted connection or similar. Guidance note: Fitting by means of lashing is not considered as permanent fitting. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

All supporting structure(s) shall be according to Pt.3 Ch.11 Sec.2 with additional requirements as given below. Guidance note: Foundations are generally understood to be part of the diving system, whereas the supporting structures structural supports are generally understood to be part of the ship's structure/hull. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

In addition to [2.1.1], foundation supporting structures supporting diving system equipment shall have scantlings based on the supported mass. The forces FU-x, FU-y and FU-z, in kN, due to the unit load for the static plus dynamic (S+D) design load scenarios shall be derived for each dynamic load case as given in Pt.3 Ch.4 Sec.5 [2.3.2] for exposed decks. For non-exposed decks and platforms the design forces shall be as given in Pt.3 Ch.4 Sec.6 [2.3]. The forces FU-x, FU-y, in kN, in longitudinal and transverse direction shall in no case be taken less than 0,5gmU. 2

Acceptable stresses, in N/mm , for the supporting structure resulting from bending moments and shearing forces calculated for the load given above, shall be according to AC-I for primary supporting members given in Pt.3 Ch.6 Sec.6 [2.1] or Pt.3 Ch.6 Sec.6 [2.2], depending on calculation method used. 2

In case of direct strength calculations the equivalent von Mises stress, in N/mm , shall satisfy:

The supporting structures and foundations shall be calculated for values of accelerations determined as shown in Pt.3 Ch.4 Sec.3 or other recognized standards. Design loads for external sea pressure on deck mounted diving system modules essential to the diving operations, shall be calculated according to Pt.3 rules for deck housing sides and ends, including supporting structures. The supporting structures of other equipment, not categorised under [2.1.2] or [2.1.3], shall be considered. Drawings showing the deck structure below the foundation shall be submitted for approval when the static forces exceed 50 kN or when the resulting bending moments at deck exceed 100 kNm. The drawings shall clearly indicate the relevant forces and bending moments acting on the supporting structure.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 62

Part 5 Chapter 10 Section 6

1.10.2 Class entry of diving systems and diving support vessels When a diving system, or part of a diving system, has been classed with another recognised classification society, evidence of previous design approval will be required. Such evidence shall include drawings of the arrangement and details bearing the approval stamp, or specifically covered by an approval letter. In addition, for components requiring certification, the corresponding certificates shall be available along with maintenance records.

The pressure vessels with supports shall be designed for a static inclination of 30° without exceeding the allowable stresses as specified in [2.1.1]. Suitable supporting structures and foundations shall be provided to withstand a collision force acting on the pressure vessels corresponding to one half the weights of the pressure vessels in the forward direction and one quarter the weight of the pressure vessels in the aft direction. Unless removal of the pressure vessel(s) is a simple operation, the supporting structure(s) shall be able to sustain the static load of the pressure vessel(s) during periodic hydro testing or it shall be possible to shore/ support the supporting structure(s) in order to avoid unacceptable deflections. The collision loads and the hydro testing loads mentioned above need not to be combined with each other or with wave-induced loads. Guidance note: Typically the chambers and large gas storage tubes will expand and contract considerably in service due to pressure variations. All supporting structures and foundations for these pressure vessels should allow for this movement. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.3 Supporting structures and foundations for handling systems and lifting appliances Supporting structures and foundations for handling systems and lifting appliances shall be determined according to Pt.3 Ch.11 Sec.2 or according to other recognized standards. Interfaces between the handling system structure and the vessel shall be especially considered. Drawings showing scantlings and joint configuration including maximum design loads shall be approved including (but not limited to) supporting structures for winches, sheaves and dampers. The dynamic coefficient shall as a minimum be taken as 2.2 when the lifting appliance is used for handling manned objects such as surface bells, baskets or hyperbaric evacuation systems. For other lifting appliances, not used for lifting people, the dynamic coefficient shall as a minimum be 1.5. The side structure of the moon pool shall be strengthened with respect to possible impact loads from diving equipment guided through the moon pool. Design loads for supporting structure(s) of bell launch and recovery systems shall be based on DNVGL-OSE402 or Pt.3 Ch.11 Sec.2 whichever is greater. Guidance note: All lifting appliances used in the operation of the diving system should be considered offshore lifting appliances. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3 Stability and floatation 3.1 General 3.1.1 The diving support vessel shall comply with the requirements for stability and floatation given in Pt.6 Ch.5 Sec.7 for the class notation SF.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 63

Part 5 Chapter 10 Section 6

2.1.2 Supporting structures and foundations for pressure vessels for human occupancy and for gas storage Pressure vessel(s) exposed to static and dynamic loads while allowing contraction and expansion of the pressure vessel(s) under pressure variations and temperature variations, shall be supported in a proper manner. The stress level in the pressure vessel(s), connected pipes, the supporting structures and foundations shall be kept within acceptable level. Deflections allowed for by the required stiffness of supporting structure shall be given as a design input to the pressure vessel manufacturer(s).

4.1 General 4.1.1 The diving support vessel shall be able to keep its position safely during diving operations. This implies a system with built in redundancy for position keeping. The position keeping system may be a mooring system with anchors or a dynamic positioning system. 4.1.2 For diving support vessels, equipped with a dynamic positioning system, the class notation DYNPOS(AUTR) or higher is mandatory. Alarms shall be initiated and set accordingly. 4.1.3 For mooring systems with anchors, the notation POSMOOR-V or higher is mandatory. 4.1.4 Between the operation centre for the positioning system and the dive operation centre there shall be: a) b)

redundant communication systems a manually operated alarm system.

5 Life support 5.1 Piping 5.1.1 General Gases vented from the diving system shall be vented to the open air away from sources of ignition, personnel or any area where the presence of those gases could be hazardous. Means shall be provided to prevent any dangerous accumulation of gases. The discharge from overpressure relief devices and exhaust shall be led to a location where hazard is not created. Piping systems carrying mixed gas or oxygen under high pressure shall not be arranged inside accommodation spaces, engine rooms or similar compartments. Piping systems shall comply with the technical requirements for class I piping in Pt.4 Ch.6. All high-pressure piping shall be well protected against mechanical damage. Piping for gas and electrical cables shall be separated. All filters/strainers shall be arranged so that they can be isolated without interrupting the supply to essential systems. Diving system sanitary and drainage systems connected to ship systems shall be designed to avoid an unintentional pressure rise in the ship system in case of malfunction or rupture of the diving systems. Piping systems intended to be used in breathing gas and oxygen systems shall be cleaned and tested for purity in accordance with an approved test method. The minimum acceptable cleanliness levels, as defined in ASTM G93-03 Standard Practice for Cleaning Methods and Cleanliness Levels for Materials and Equipment Used in Oxygen-Enriched Environments, shall be: 1) 2) 3)

ASTM Level B for non volatile residue in oxygen lines ASTM Level D for non volatile residue in breathing gas lines ASTM Level 175 for particulate contamination.

5.1.2 Oxygen systems The discharge from overpressure relief devices and exhaust from O2 systems shall be ducted to a safe place and not close to a source of ignition, engine room exhaust or ventilation from galley.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 64

Part 5 Chapter 10 Section 6

4 Position keeping

5.2.1 General Where gas mixtures with oxygen content less than 20% are stored in enclosed spaces, there shall be two oxygen analysers with an audio-visual low level alarm in addition to the ventilation requirements in [5.2.2]. These analysers shall be mounted such that one is reading the upper levels and the other is reading the lower levels of the enclosed space. 5.2.2 Oxygen gas storage Oxygen bottles shall be installed in a well-ventilated location. The rooms shall be separated from adjacent spaces and ventilated according to [7.1.3] and shall be fitted with an audio-visible oxygen alarm, at a manned control station. Oxygen bottles shall not be stored near flammable substances. Oxygen shall not be stored or ducted in any form close to combustible substances or hydraulic equipment. For diving support vessels with class notation Fire fighter, the oxygen gas bottles shall be specially protected from heat that may radiate from a fire that is being extinguished.

6 Power provisions, control and communications 6.1 Electrical systems 6.1.1 Objective General requirements for electrical systems are given in Pt.4 Ch.8 and DNVGL-OS-E402. The purpose of this section is to specify additional requirements for electrical systems and equipment serving diving systems. Emphasis is therefore placed on the special needs associated with the design and manufacture of diving systems. 6.1.2 Design philosophy of electrical systems serving diving systems All electrical equipment and installation, including power supply arrangements, shall be designed for the environment in which they will operate to minimize the risk of fire, explosion, electrical shock and emission of toxic gases to personnel, and galvanic action of the surface compression chamber or diving bell. Electrical cables and piping for gas shall be separated. In the event of failure of the main source of electrical power supply to the diving system an independent source of electrical power should be available for the safe termination of the diving operation. It is admissible to use the ship's emergency source of electrical power as an emergency source of electrical power if it has sufficient electrical power capacity to supply the diving system and the emergency load for the vessel at the same time. The alternative source of electrical power shall be located outside the machinery casings to ensure its functioning in the event of fire or other casualty causing failure to the main electrical installation. Interface between diving system and the ship or floating structure shall be provided with suitable electric lighting. Primary and emergency lighting in all critical handling areas shall be provided.

6.2 Communication 6.2.1 General The communication system shall be arranged for a fixed direct two-way communication between the control stands and: a) b)

diving system handling positions dynamic position control centre

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 65

Part 5 Chapter 10 Section 6

5.2 Gas storage

bridge, ship's command centre or drilling floor crane ROV control stand.

This fixed communication systems shall also be arranged for direct two-way voice communication between the dive control room and the SAT control room (for Diving support vessel (SAT)). 6.2.2 Testing The communication system shall be functionally tested after installation.

7 Fire protection 7.1 Fire prevention 7.1.1 Objective General requirements for fire protection are given in the rules Pt.4 Ch.10. The purpose of this section is to specify additional requirements for fire protection of areas containing diving equipment with auxiliaries and systems to be connected to the diving compression chambers and diving bells. 7.1.2 Application and scope These requirements apply to all systems. However, some systems may be located on open deck. In these cases the requirements for insulation against adjacent spaces and requirements for sprinkler systems shall be evaluated on a case by case basis. 7.1.3 Arrangement and materials Enclosed outer area shall have A-60 class towards other enclosed spaces. Outer area may be subdivided into several spaces by A-0 class. There shall be no direct access between categories A machinery spaces outside of outer area. At least one of the required escape routes from spaces not being part of outer area shall be independent of outer area. All doors between outer area and other adjacent enclosed spaces shall be of selfclosing type. Piping and cables essential for the operation of the diving system are regarded as part of the system and shall be laid in separate structural ducts insulated to A-60 class standard where these transit from other spaces as main switch board room or engine room into outer area. Outer area in the ship or floating structure shall be arranged in spaces or locations which are adequately ventilated. When situated in enclosed spaces the outer area shall be fitted with separate mechanical ventilation with minimum 8 air changes per hour. Insulation materials used in connection with the diving system shall be of fire-retardant type in order to minimize the risk of fire and sources of ignition.

7.2 Fire detection and alarm systems 7.2.1 Outer area When situated in enclosed spaces, the outer area shall be equipped with automatic fire detection and alarm systems complying with SOLAS Reg. II-2/7.1 and FSS Code Ch 9 as mandated by Pt.4 Ch.11 Sec.4. The section or loop of detectors covering the outer area shall not cover other spaces. Fire detection panel shall be placed on the bridge, with repeater panel at dive control room and in engine control room and provisions shall be made for warning of faults. A visual repeater, showing the alarm condition, shall be placed at the saturation- and diving control stand. Outer area: Those areas of the diving system that are exposed to atmospheric conditions during operation, i.e. outside the inner system and the room or area that surrounds or contains the diving system.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 66

Part 5 Chapter 10 Section 6

c) d) e)

7.3.1 Outer area Interior spaces containing diving equipment such as surface compression chambers, diving bells, gas storage, compressors and control stands shall be covered with a suitable fixed fire-extinguishing system. When situated in enclosed spaces, the outer area shall be equipped with a fixed, manually actuated fire extinguishing system with such a layout as to cover the complete system. Release positions for these systems shall be at the dive control room, bridge and/or other positions as required case by case. Coverage shall be sufficient to cover at least the largest area enclosed by A-0 class. The extinguishing system shall be either: a) b)

a pressure water spraying system approved for use in machinery spaces of cat. A, or an equivalent fixed gas fire-extinguishing system in accordance with the FSS Code and IMO MSC/circ. 848, amended by MSC/Circ. 1267.

If a gas system is selected, the agent shall be of a type not hazardous to humans in the concentration foreseeable in the protected space. The concentration shall be below the NOAEL as defined in IMO MSC/ Circ.848/1267. When pressure vessels are situated in enclosed spaces, a manually actuated water spray system having an 2 application rate of 10 l/m /per minute of the horizontal projected area should be provided to cool and protect such pressure vessels in the event of external fire. For equivalent water-mist fire-extinguishing systems with 2, 2 application rate less than 5 l/min/m an additional object protection of 5 l/min/m is accepted as equivalent 2 to 10 l/min/m . Release positions for these systems shall be at the dive control room, bridge and/or other positions as required case by case. The capacity shall be sufficient to cover the most demanding space enclosed by A-class divisions. When pressure vessels are situated on open decks, fire hoses may be considered as providing the necessary protection. When situated on open deck, the outer area shall be provided with fire extinguishing equipment, which shall be considered in each case. Hyperbaric evacuation systems shall be provided with fire extinguishing systems enabling launching of the hyperbaric evacuation unit in the event of a fire. Object protection of area for hyperbaric evacuation systems shall be activated automatically upon any confirmed fire onboard.

7.4 Miscellaneous equipment 7.4.1 Fire-fighter’s outfit A complete set of fire-fighter's outfit complying with Pt.4 Ch.11 Sec.2 for each person required for operation of the diving system during a fire shall be located at the main control stands. The sets are additional to other sets on board. Breathing apparatus are required for control stations manned during recovery of bell or launching of hyperbaric evacuation unit. Guidance note: Fire-fighter's outfit is recommended in consideration of the time it may take for recovery of the divers from the water, into the bell and all the way up to the hyperbaric evacuation system. The operator(s) of the diving system may be exposed to hot environments which render evacuation impossible unless they are protected whilst performing their work. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

7.4.2 Portable fire extinguishers Portable fire extinguishers shall be of approved type and comply with the provisions of the FSS Code. Portable fire extinguishers shall be distributed throughout the space containing the diving system so that no point in the space is more than 10 m walking distance from an extinguisher.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 67

Part 5 Chapter 10 Section 6

7.3 Fire extinguishing

A portable fire extinguisher shall be fitted at the control stand. Spare charges or extinguishers shall be provided on board as follows: — 100% for the first 10, and — 50% for remaining extinguishers.

8 Hyperbaric evacuation 8.1 General 8.1.1 General An evacuation system shall be provided having sufficient capacity to evacuate all divers under pressure, in the event of the ship having to be abandoned, and shall be in accordance with the provisions of the Guidelines and Specifications for Hyperbaric Evacuation Systems adopted by the IMO organization by resolution A.692(17). Hyperbaric evacuation systems on diving support vessels classed by the Society shall comply with these statutory requirements as interpreted in DNV-RP-E403. Guidance note: As life saving appliances are governed by statutory regulations, there may be overriding requirements for hyperbaric evacuation systems (HES). Consequently, it is important to inform the Society at an early stage what flag administration is intended for the diving support vessel. It is the Society’s intention to apply SOLAS requirements for hyperbaric evacuation systems as far as is practical. This includes the launching arrangement. In the cases where the system does not comply with the prescriptive requirements in SOLAS, the Society shall verify evaluations and tests that show substantially equivalent conformance with the recommendations. This is in accordance with recommendations given in SOLAS Ch. III Part A Regulation 4. Guidelines and Specifications for Hyperbaric Evacuation Systems, adopted by the IMO organization by Resolution A.692(17) on 6 November 1991, shall be included as normative references under SOLAS. The Society interpretations to these guidelines are given in DNV-RP-E403 Hyperbaric Evacuation Systems. Yards, owners or designers will have to carry out engineering analyses according to the new SOLAS Ch. III, Reg. 38 as amended by IMO Res. 216(82). ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 68

Part 5 Chapter 10 Section 6

One of the portable fire extinguishers shall be fitted near each entrance.

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for seismographic research operations with particular focus on the robust design of the seismic equipment hangar; the ability to maintain propulsion power and vessel manoeuvrability through adapted bridge design and navigation systems.

1.2 Scope 1.2.1 These rules include requirements for hull strength, systems and equipment applicable to seismographic research vessels.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in [4] of this section may be given the class notation Seismic vessel. Vessels built in compliance with the relevant additional requirements in [5] of this section may be given the class notation Seismic vessel(A). Qualifier (A) is optional. Vessels with qualifier (A) shall hold the following additional class notations: — RP(+) or RP(3,x%,+), see Pt.6 Ch.2; or DYNPOS(AUTR) or DYNPOS(AUTRO), see Pt.6 Ch.3; or DYNPOS(ER), see Pt.6 Ch.3 — E0 or ECO, see Pt.6 Ch.2 — NAUT(OSV), see Pt.6 Ch.3

2 Racking of seismic hangar 2.1 Transverse racking 2.1.1 General A transverse racking strength assessment shall be carried out for the seismic hangar following the requirements given in this sub-section. Special attention shall be given to the connections between transverse structural members to the bulkhead deck or the uppermost deck level with high racking rigidity. Intersections between horizontal and transverse members shall be assessed in areas subjected to high racking deformations, i.e. response caused by roll motion acting on the cargo at multiple decks combined with self-weight of structure and equipment. 2.1.2 Scope of racking calculations in way of seismic hangar Transverse strength is provided by the deep vertical web frames in the ship’s side and/or transverse bulkheads in the forward area of the seismic hangar. For vessels with length L < 120 m, a simplified racking assessment model using beam elements (grillage analysis) will be accepted for the evaluation of the adequacy of the transverse strength for the ultimate limit state (ULS). 2

Fatigue assessment will not be required if the dynamic nominal stress is less than 80 N/mm .

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 69

Part 5 Chapter 10 Section 7

SECTION 7 SEISMOGRAPHIC RESEARCH VESSELS

For vessels with length L ≥ 120 m, calculation scope based on FE partial ship structural analysis shall be applied. A separate fatigue limit state analysis (FLS) shall be carried out according to Ch.3 Sec.2 [4].

3 Loads 3.1 Loads for racking strength assessment of seismic hangar in transit condition 3.1.1 Loading condition for racking The loading condition, which in combination with relevant dynamic load cases defined in [3.1.3] results in the maximum racking moment about the bulkhead, shall be chosen for the ULS transverse strength analysis. The design racking moment shall be calculated according to [3.1.2]. The actual GM value for this design load case shall be determined and applied since it has a significant influence on the dynamic load cases. In no case shall the GM value for the design still water loading condition be smaller than 0.05B. 3.1.2 Racking moment calculation (screening of highest design load) The racking moment is calculated using both cargo and fully loaded equipment weight (mc) and the selfweight (ms) to obtain the total mass. If not specified by the designer, an average minimum distributed 2 load equal to 0.2 t/m shall be applied for the accommodation decks, in addition to the self-weight. For unloaded weather decks, it is sufficient to include the load corresponding to the self-weight if no deadweight is specified. The transverse force on each deck level is obtained as the total mass times the transverse acceleration corresponding to the relevant equivalent design wave (EDW) given in [3.1.3]. Thus, the racking moment in kNm, may be estimated as:

where:

mc,i ms,i ay,i zi zmain

= mass on deck number i, in t = self-weight of deck number i, in t

2

= transverse acceleration at deck number i, in m/s , for the dynamic load cases specified in [3.1.3] = vertical distance above base line for deck number i, in m = vertical position above base line for bulkhead deck, in m.

Guidance note: A high racking moment is achieved if the load is located on the upper decks. However this result in lower GM values and thus also lower transverse accelerations which will reduce the racking moment. Usually, several loading conditions for racking analysis should be reviewed using the simplified racking moment calculation described in this paragraph. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.3 Dynamic load cases The design wave load cases which shall be used to evaluate the transverse strength of the ship structure is the beam sea load cases BSR (1P/2P) and/ or BSR (1S/2S). For ship structures with symmetrical arrangement of racking constraining elements, only BSR(1P/2P) or BSR(1S/2S) needs to be examined. 3.1.4 Load combinations in transit condition for ULS The loading condition from [3.1.1] shall be combined with the dynamic load cases as described in [3.1.3]. The external sea pressure shall be applied according to Pt.3 Ch.4 Sec.5 Table 8. Load combination factors

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 70

Part 5 Chapter 10 Section 7

Under special consideration finite element analysis based on partial ship structural model may be required on a case by case basis. Acceptable calculation and modelling methods are given in Pt.3 Ch.7.

Transverse accelerations shall not be taken less than 0.5g. 3.1.5 FE load application The deck load may generally be applied as distributed vertical and transverse loads based on load combination as described in [3.1.4]. The steel self-weight shall be included.

3.2 Loads for primary supporting members 3.2.1 Design load sets for prescriptive rule check Design load sets and load combinations of static and dynamic loads for tank and watertight boundary structure, external shell envelope structure e.g. bottom structure, side shell primary members and deck structure is given in Pt.3 Ch.6 Sec.2 Table 2. 3.2.2 Load sets and load combinations for direct analysis The load pattern described in Table 1 shall be assessed to ensure that the primary support members have sufficient strength.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 71

Part 5 Chapter 10 Section 7

for hull girder loads and accelerations shall be applied according to Pt.3 Ch.4 Sec.2 Table 3 with the internal cargo, equipment and steel weight loads.

DNV GL AS

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

Table 1 Load patterns Transit condition Load pattern

1)

Description

Strength members

5)

LC 1

LC 2

Acceptance Load Draught criteria pattern

AC-II Fully loaded seismic equipment in stored position. Deck load as specified by designer

5)

Seismic operational condition

TSC

2)

LC 1 5)

— pillars — side structure — deck structure AC-I

T

BAL

LC2

3)

6)

LC3 6)

4)

1)

Description

Normal operation of seismic equipment on each hangar deck. Weight of the equipment can be reduced by the weight of deployed cables. Deck load as specified by designer. Maximum transverse loading of seismic equipment. Weight of the equipment can be reduced by the weight of deployed cables. Sea pressure need not be included. Maximum vertical loading of seismic equipment. Weight of the equipment can be reduced by the weight of deployed cables. Sea pressure need not be included.

Strength members

Acceptance Draught criteria

— pillars — side structure — deck structure

— side structure — deck structure

AC-I

T

BAL

— pillars — side structure — deck structure

1)

Special load case to evaluate strength of individual strength members under heavy seismic equipment. Load distribution/combination shall be based on information from a seismic equipment load plan as specified by designer.

2)

Combinations of equipment loads shall include maximum operational loads on seismographic handling equipment, e.g. winches, towing points, which are assumed to be at least one line with breaking load and remaining lines with safe working load times the dynamic factor.

3)

In case of maximum transverse loading, safe working load on towing points times dynamic factor shall be combined with maximum breaking strength on at least one line in the most unfavourable position (normally the outermost line). If the design specification should include combinations with more than one piece of equipment with breaking load then this shall be included in the load specification of the seismic equipment hangar.

4)

For maximum vertical loading the breaking load is normally to be applied to the mid-span line and combined with SWL times dynamic factor for the remaining lines. If the design specification should include combinations with more than one piece of equipment with breaking load then this shall be included in the load specification of the seismic equipment hangar.

5)

For the lowermost deck on semi- enclosed hangars, the design load shall be taken as the greater value of the rule sea pressure and specified 2 2 deck load when below 2 t/m in combination with sea pressure. The sea pressure does not need to exceed 60 kN/m , when it is used in combination with the deck load. For the remaining decks on semi enclosed hangars, the design load shall be taken as the greater value of the rule sea pressure and deck load. For open weather deck located 1.7CW meter or more, see Pt.3 Ch.4 Sec.4, above the Summer Load Waterline,

Page 72

the design load shall be taken as the greater value of the rule sea pressure and deck load. 6)

Deck load to be as specified by the designer or minimum rule values with no dynamic factors, i.e. mass times gravity. Self-weight of storage winches or other equipment not used during operation shall be included with vertical load component, i.e. 1.0g.

Part 5 Chapter 10 Section 7

For internal decks in transit condition for load pattern LC1, the UDL design load sets applies and the Pdl-d may be based on envelope acceleration according to Pt.3 Ch.4 Sec.3 [3.3]. The following design load sets then applies: a) b)

UDL-1h: (Pdl-s + Pdl-d) combined with maximum hull girder vertical bending moment in hogging, i.e. Mwvh + Msw-h based on HSM-2 UDL-1s: (Pdl-s + Pdl-d) combined with maximum hull girder vertical bending moment in sagging, i.e. Mwvs + Msw-s based on HSM-2.

Optionally, the accelerations for the considered dynamic load case may be applied. Then the number of applicable load sets will double, in order to maximize both local pressure and hull girder vertical bending moment, as described in Pt.3 Ch.6 Sec.2 Table 2. 3.2.4 Breaking load need not to be taken greater than the force causing the winch to render. 3.2.5 A design dynamic factor of not less than 1.3 shall be applied to the static SWL of the seismic handling equipment.

4 Hull local scantling 4.1 Primary supporting members being part of seismic equipment hangar 4.1.1 General The strength of primary structural members that form part of a grillage system, such as deck girders, side web frames, pillars, floors and girders in double bottom shall be determined by direct strength analysis either by the use of a beam- or FE part ship model. 4.1.2 Beam analysis Beam analysis may be accepted in order to evaluate bending and shear stresses in webs and flanges of grillage structure under lateral loads such as decks, double bottom and side structure under cargo or liquid pressure, e.g. sea pressure, tank pressure etc. The effective plate breadth in bending of the primary strength members shall be calculated according to Pt.3 Ch.3 Sec.7 [1.3]. 4.1.3 Buckling check of plate panels The normal stresses and shear stresses taken from strength assessment to be applied for buckling capacity calculation of plate panels, as given in Pt.3 Ch.8 Sec.4, shall be corrected as given in DNVGL-ST-0128 Sec.3 [2.2.7]. Buckling strength shall be considered for panels with high in-plane stresses, e.g. decks and ship sides, with acceptance criteria given in Ch.8 Sec.4. For buckling assessment fully effective plate flange may be used. 4.1.4 Acceptable stress level 2 Acceptable stresses, in N/mm , for the supporting structure resulting from bending moments and shearing forces calculated for the loads given above, shall be according to AC-I and AC-II for primary supporting members given in Pt.3 Ch.6 Sec.6 [2.2]. 2

In case of direct strength calculations the equivalent von Mises stress, in N/mm , shall satisfy:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 73

Part 5 Chapter 10 Section 7

3.2.3 Design load sets for beam analysis Relevant design load sets for transit condition are described in the rules Pt.3 Ch.6 Sec.2 Table 2 and Pt.3 Ch.6 Sec.8 Table 1 shall be applied to the model.

4.2.1 Local structural strength in way of the equipment foundation shall be in compliance with Pt.3 Ch.11 Sec.2. 4.2.2 In case the winch is supported by two deck levels, then local support at one deck level shall be capable of bearing all vertical loads from the winch. 4.2.3 When part of the equipment is acting as structural hull support, i.e. winch frame providing pillar support for the decks, it shall comply with the strength requirements as for the main structure with respect to the design loads and rule acceptance criteria. 4.2.4 In cases when equipment is being used as hull structural support this shall be stated in memorandum to owner (MO) and appendix to classification certificate.

4.3 Strengthening for side-by-side mooring 4.3.1 The SWL for the mooring bollard shall be at least three (3) times the minimum breaking load of the mooring lines according to the vessel’s equipment letter, or based upon the designer’s specification for the minimum breaking load to be used for side-by-side mooring lines. 4.3.2 The mooring line specification and restrictions on operation of the mooring bollards shall be stated in the appendix to classification certificate and in a memorandum to owner. 4.3.3 The strength of supporting deck structure shall be based on the mooring bollard’s SWL times 1.5. 2

4.3.4 Acceptable stresses, in N/mm , for the scantlings of the supporting deck structure resulting from bending moment M, in kNm, and shear force Q, in kN, calculated for the load given above are: 2

σb

= bending stress, in N/mm , taken as:

τ

= average shear stress, in N/mm , taken as:

Ashr Z

= net shear area, in cm

2

3 3

= net section modulus, in cm . 2

In case of direct strength calculations the equivalent von Mises stress, in N/mm , shall satisfy:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 74

Part 5 Chapter 10 Section 7

4.2 Supporting structures for seismic handling equipment

5.1 Work boat davits and winches 5.1.1 Where fitted, work boat davits and winches, unless otherwise required by national authorities shall comply with SOLAS 1974 and the LSA Code, with the following exceptions: — — — —

no requirements for heel or trim unless specified by operator stored mechanical power not required, however lowering in dead ship condition shall be possible no requirements for hoisting or lowering speed if estimated dynamic factor exceeds 1.5, shock damper arrangement is required.

5.1.2 In addition to strength requirements given in above regulations, fatigue according to a recognised standard shall be considered. 5.1.3 Testing at factory and after installation on board shall be performed in line with IMO MSC. 81(70) part 2.

5.2 High pressure air system 5.2.1 The piping system shall comply with the requirements in Pt.4 Ch.6. In addition, the requirements specified in [5.2.2] to [5.2.11] shall be fulfilled. 5.2.2 High pressure pipes shall not be installed in the vicinity of gangways or other spaces which are in normal use by personnel. If this cannot be avoided, shielding or equivalent arrangement shall be applied. Any manifold and pressure relief valve shall be shielded to safeguard any operator. The pressure relief valves shall be arranged for venting to exhaust or overboard. Guidance note: Example of appropriate shielding may be punched steel shields. The shielding may also be removable in order for accessing depressurized equipment. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.3 Pipes should be inclined relative to the horizontal. Water pockets in the pipeline shall be avoided as far as practicable. If this cannot be avoided, means of drainage shall be arranged. 5.2.4 All manifolds and other locations where liquid may accumulate shall be arranged with possibilities for efficient drainage. Automated drains shall be arranged for air receivers, with additional possibility for manual operation. 5.2.5 Lubricating oil points for the air guns shall not be located in the vicinity of manifolds. If this cannot be avoided, there shall be arranged automatic shut-down of lubrication pumps when the high pressure air system is not pressurized. 5.2.6 All valves shall be automatically operated in order to prevent adiabatic compression or water hammer in the system. Alternatively, the system shall always be de-pressurized before operating any valves. Guidance note 1: Opening time of a valve should be at least 10 seconds. Controlled pressure adjustment before opening a high pressure valve may, in some cases serve as an equivalent to automatically operated valves. By adjusting the system pressure to 1:8 of design pressure, the risk of generating high temperatures through adiabatic compression is negligible. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 75

Part 5 Chapter 10 Section 7

5 Systems and equipment

In cases where automatic operation is not possible to install, each valve should be permanently marked with warning against rapid opening. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.7 Air intakes for the compressors shall be so located as to minimize the intake of oil or water contaminated air. 5.2.8 Pipes from air compressors with automatic start shall be fitted with a separator or similar device to prevent condensate and HP piping shall be done in a way to prevent condensate from draining back into compressors. 5.2.9 Cylinder banks shall be located in areas which are not in normal use by personnel. The area shall be arranged for high pressure air to expand in case of an explosion. Guidance note: Proper shielding of connected piping and valves may be considered as an equivalent solution if designated areas cannot be arranged. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.10 There shall be at least one burst disc installed at the manifold, and one at the cylinder bank. The discs shall be directed away from working areas. 5.2.11 The piping shall be hydrostatically tested for at least 30 minutes in the presence of a surveyor after installation on board with the following test pressure: PH = 1.5 P where:

PH P

= test pressure in bar = design pressure in bar as defined in Pt.4 Ch.6 Sec.7.

The test pressure need not exceed the design pressure by more than 70 bar.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 76

Part 5 Chapter 10 Section 7

Guidance note 2:

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for stimulation of wells for production of oil and or gas.

1.2 Scope 1.2.1 These rules include requirements for tank systems and equipment, piping systems, control and monitoring systems applicable to well stimulation vessels, including: — personnel protective equipment — intact and damage stability of the vessel. Guidance note: Arrangements involving return of fluids from the well are not covered by the rules. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section may be given the class notation Well stimulation vessel.

2 Hull 2.1 General 2.1.1 The hull structural strength shall be as required for the main class taking into account necessary strengthening of supporting structures for the well stimulation equipment during transit and operation. 2.1.2 All load effects caused by heavy well stimulation deck equipment shall be taken into account in the structural design for both transit and operational condition.

3 Arrangement 3.1 Tanks and pumping arrangement 3.1.1 Tanks for acid and liquefied nitrogen shall be located at a minimum distance of 760 mm from the vessel's side and bottom. 3.1.2 Tanks and pumping arrangements shall not be located within accommodation areas or machinery spaces. 3.1.3 Tanks and piping systems for the well stimulation plant shall be separated from the machinery and ship piping systems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 77

Part 5 Chapter 10 Section 8

SECTION 8 WELL STIMULATION VESSELS

3.1.5 Tanks and pumping arrangements for liquid additives having flashpoint below 60°C shall comply with relevant requirements of Pt.6 Ch.5. Arrangement of pump room for LFL (low flashpoint liquids) substances adjacent to the LFL tanks and without separating cofferdams may be considered in each case. 3.1.6 Requirements for tanks and pumping arrangements for chemicals other than acids dealt with under [7] will be considered in each case with due regard to the properties of the chemicals and applicable requirements of Ch.6.

3.2 Tank venting 3.2.1 Outlets from safety valves of nitrogen tanks shall be lead to open deck. Outlet pipes shall be arranged and supported in order to allow thermal expansion during release of cold gas. Penetrations of decks or bulkheads shall be such that the structures are thermally isolated from the cold pipes. 3.2.2 Vent outlets from acid tanks shall be lead to open deck. The outlets shall have a minimum height of 4 m above the deck and located at a minimum horizontal distance of 5 m from openings to accommodation and service spaces. 3.2.3 Vent outlets from acid tanks shall have pressure/vacuum valves. The outlets shall be provided with flame screens.

3.3 Access openings 3.3.1 Enclosed spaces containing tanks, piping, pumps and blenders for uninhibited acid shall have entrances direct from open deck or through air locks from other spaces. The air lock shall have independent mechanical ventilation.

3.4 Acid spill protection 3.4.1 Floors or decks under acid storage tanks and pumps and piping for uninhibited acid shall have a lining of corrosion resistant material extending up to a minimum height of 500 mm on the bounding bulkheads or coamings. Hatches or other openings in such floors or decks shall be raised to a minimum height of 500 mm above. 3.4.2 Flanges or other detachable pipe connections shall be covered by spray shields. 3.4.3 Portable shield covers for connecting flanges of loading manifold shall be provided. Drip trays of corrosion resistant material shall be provided under loading manifold for acid.

3.5 Drainage 3.5.1 Spaces housing tanks and pumping and piping for acids or additives shall have a separate drainage system not connected to the drainage system for other areas. 3.5.2 Drainage arrangement for acids shall be of corrosion resistant materials.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 78

Part 5 Chapter 10 Section 8

3.1.4 Remote control of the well stimulation processing plant shall be arranged from a position outside the area where the well stimulation systems are located.

4.1 Ventilation of spaces containing installations for storage or handling of acid 4.1.1 The spaces shall have an independent mechanical ventilation with a capacity of minimum 30 air changes per hour.

4.2 Ventilation of other spaces containing equipment for well stimulation 4.2.1 Spaces containing installations for liquid nitrogen and liquids containing inhibited acid shall have a mechanical ventilation system with a minimum capacity of 20 air changes per hour. The ventilation system shall be independent of the ventilation system for the accommodation. 4.2.2 Ventilation of spaces for storage and handling of dry and liquid additives will be considered in each case depending on the flammability, toxicity and reactivity properties of the additives to be used.

5 Electrical equipment, instrumentation and emergency shut-down system 5.1 Electrical equipment or other ignition sources in enclosed spaces containing acid tanks and acid pumping arrangements 5.1.1 Only equipment certified as safe for operation in hydrogen/air atmosphere shall be used.

5.2 Vapour detection 5.2.1 Vapour detection and alarm systems for hydrogen or hydrogen chloride gas shall be provided in enclosed or semi-enclosed spaces containing installations for uninhibited acid. 5.2.2 Spaces containing tanks and piping for liquid nitrogen shall be equipped with oxygen deficiency monitoring.

5.3 Gauging and level detection 5.3.1 Tanks for liquefied nitrogen shall have gauging and level detection arrangements in accordance with Ch.7 Sec.13. 5.3.2 Tanks for hydrochloric acid shall have a closed gauging system. A high level alarm shall be provided. The alarm shall be activated by a level sensing device independent of the gauging system. 5.3.3 Spaces containing equipment and storage tanks for the well stimulation system shall be provided with detection and alarm system for liquid leakages.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 79

Part 5 Chapter 10 Section 8

4 Ventilation

5.4.1 Emergency stop of all pumps in the oil well stimulation system shall be arranged from one or more positions located outside the area accommodating the system. 5.4.2 Emergency shut-off valves shall be provided in liquid nitrogen outlet lines from each nitrogen tank. The shut off valves shall be remotely controlled from one or more positions outside the area accommodating the oil well stimulation system. 5.4.3 Emergency de-pressurising and disconnection of the transfer hose shall be arranged from the central control position and from the bridge.

6 Liquid nitrogen system 6.1 Materials 6.1.1 The materials shall be in accordance with Ch.7 Sec.6.

6.2 Storage tanks 6.2.1 The design and testing of the tanks for liquid nitrogen shall be in accordance with Ch.7 Sec.22 as required for independent cylindrical tanks type C.

6.3 Pumping and piping 6.3.1 The requirements of Ch.7 Sec.5 apply.

7 Acid system 7.1 Materials 7.1.1 In general Ch.6 Sec.2 applies. 7.1.2 Storage tanks, pumping and piping for uninhibited acid shall be of corrosion resistant material or shall have internal lining of corrosion resistant material.

7.2 Storage tanks 7.2.1 The rules in Ch.6 Sec.5 apply.

7.3 Pumping and piping 7.3.1 The rules in Pt.4 Ch.6 apply. 7.3.2 The flexible hose with end connectors shall be in accordance with a recognised standard.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 80

Part 5 Chapter 10 Section 8

5.4 Emergency shut-down system

8.1 Decontamination showers and eye washes 8.1.1 Decontamination showers and eye washes shall be fitted at convenient locations. 8.1.2 The showers and eye washers shall be operable also under freezing conditions. Temperature control of the water shall be provided in order to avoid excessive temperatures.

8.2 Personnel protective equipment 8.2.1 Protective equipment shall be kept onboard in suitable locations as required by the IMO International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (IBC Code) Res. MSC.4(48) as amended, for carriage of hydrochloric acid.

9 Intact and damage stability 9.1 General 9.1.1 The vessel shall comply with the requirements for intact and damage stability given in Ch.9 Sec.2 [5] and Pt.6 Ch.5 Sec.6 (SF notation).

10 Operation manual 10.1 General 10.1.1 The vessel shall have an approved operation manual readily available on board. The manual shall give instructions and information on safety aspects related to well stimulation processing. 10.1.2 The operation manual shall give particulars on: — — — —

protective equipment storage and handling of fluids and dry additives transfer operations emergency shut-down and disconnection.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 81

Part 5 Chapter 10 Section 8

8 Personnel protection

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels capable of fighting fires onboard ships and on offshore and onshore structures. The vessels shall be able to operate as additional fire-fighting stations by providing water to combat fire and to support ongoing rescue operations.

1.2 Scope 1.2.1 The requirements for fire fighter vessels encompass the following: — the vessel's fire fighting capability — the vessel's stability and its ability to keep its position when the fire fighting water monitors are in operation — the vessel's passive and active heat radiation protection against external fires. 1.2.2 Arrangements for survivor rescue and recovery is not part of the Fire fighter notation. 1.2.3 Granting of Fire fighter notation is based on the assumption that the following has been complied with when operating the vessel as a fire fighter: — the instructions laid down in the operation manual for fire fighting are being followed — the vessel will carry a sufficient quantity of fuel oil for continuous fire fighting operations, with all fixed water monitors in use for a period of not less than: 24 hours for class notation qualifiers I and I+, and 96 hours for class notation qualifiers II and III — foam-forming liquid for at least 30 minutes continuous foam production for the fixed foam monitors is stored onboard vessels with class notation qualifier III — foam-forming liquid for at least 30 minutes continuous foam production by the mobile generator is stored in suitable containers onboard vessels with class notation qualifiers II or III — the crew operating the fire fighting systems and equipment has been trained for such operations, including the use of air breathing apparatus — the skill of the crew is maintained by exercises (drills).

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements specified in this section may be given the class notation Fire fighter with one or more of the following class notation qualifiers I, I+, II or III. 1.3.2 The class notation qualifiers I and I+ imply that the vessel has been built for early stage fire fighting and for support of rescue operations onboard or close to structures or ships on fire. 1.3.3 To meet its objectives, a Fire fighter(I) vessel shall be designed with active protection, giving it the capability to withstand higher heat radiation loads from external fires. In addition, the vessel includes a sufficient set of fire fighting equipment. 1.3.4 Class notation qualifier I+ differentiates itself from I with a higher reliability and capability. In addition to active protection as named in [1.3.3], the vessel shall have passive protection, giving it the capability to withstand the higher heat radiation loads also when the active protection fails. In addition, the vessel incorporates a longer throw length.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 82

Part 5 Chapter 10 Section 9

SECTION 9 FIRE FIGHTERS

1.3.6 Qualifier III requires a larger water pumping capacity and more comprehensive fire fighting equipment when compared to the II. 1.3.7 If a vessel has been fitted with a fire fighting systems and equipment in accordance with the class notation qualifiers II or III and has also been designed with passive and/or active heat radiation protection in accordance with the class notation I+ or I, then a combination of the two notations may be given. 1.3.8 A detailed scope for the different class notation qualifiers follows from the content of this chapter by an indication or a statement in wording to which class notation qualifier the requirements applies to. Without such an indication or statement, the requirement is applicable for any class notation qualifier. Guidance note: [3.1] Active fire protection (Qualifiers I and I+) indicates that the paragraph is applicable for class notation qualifiers I and I+ only. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3.9 Vessels not fully in compliance with this section or not specifically built for the services intended to be covered by this section but which have special fire fighting capabilities in addition to their regular service, may be specially considered and reviewed under the intent of this section as they relate to fire fighting. Such vessels, complying as a minimum with [9] of this section, may be given the class notation Fire fighter (Capability). The standard applied, with relevant data on the extent of this special fire fighting capability will be entered into the appendix to the class certificate and such special fire fighting systems will be subject to annual surveys.

1.4 Testing requirements 1.4.1 Testing shall be carried out to verify that the vessel, fitted with fire fighting systems and equipment, is able to operate as intended and has the required capacities. The height and length of throw of the water monitors shall be demonstrated. The angle of list, with water monitors in operation in the most unfavourable position, shall also be measured. 1.4.2 For class notation qualifiers I and I+, fire main capacities shall be tested as follows: 2

— The static pressure measured at the fire hydrant manifold shall be not less than 0.25 N/mm with four (4) jets of water from hoses simultaneously engaged to one of the fire hydrant manifolds required in [7.1]. — In a separate test, both water monitors shall be tested in operations simultaneously with the active heat radiation protection system in operation for not less than one (1) hour or until the temperature of the dedicated fire fighter pumps' prime movers are stabilised. 1.4.3 For class notation qualifier II, the number of hoses simultaneously engaged shall be not less than six (6) and for class notation qualifier III not less than eight (8) for the test specified in [1.4.2].

2 Basic requirements 2.1 Operation manual 2.1.1 The following information shall be included in an approved operation manual kept onboard: — line of responsibility and delegation of tasks — description of each fire fighting system and the equipment covered by the classification — safety precautions and start-up procedures

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 83

Part 5 Chapter 10 Section 9

1.3.5 The class notation qualifiers II and III imply that the vessel has been built for continuous fighting of large fires from a safe distance and for the cooling of structures on fire.

2.2 Manoeuvrability 2.2.1 The vessel shall have side thrusters and propulsion machinery of sufficient power for adequate manoeuvrability during fire fighting operations. 2.2.2 Side thruster(s) and main propeller(s) shall be able to keep the vessel at a standstill in calm waters at all combinations of capacity and direction of throw of the water monitors, and the most unfavourable combination shall not require more than 80% of the available propulsion force in any direction. 2.2.3 If the system design is such that, in any operating combination, it will be possible to overload the power supply, a power management system shall be arranged. This system shall include alarm at 80% of available power and automatic action at 100% available power. 2.2.4 The operation of the side thruster(s) and the main propeller(s) shall be simple and limited to the adjustment of: — resultant thrust vector for the vessel — possible adjustment of the turning moment — possible adjustment of heading (gyro stabilised). Operation shall be arranged at the workstation where the monitors are controlled. 2.2.5 It shall be visually indicated when this workstation has control. Failure in the control system shall initiate an alarm.

2.3 Searchlights 2.3.1 As an aid for operations in darkness, at least two adjustable searchlights shall be fitted onboard, capable of providing an illumination level of 50 lux in clear air, within an area not less than 10 m diameter, to a distance of 250 m.

3 Protection of the vessel against external heat radiation 3.1 Active fire protection (class notation qualifiers I and I+) 3.1.1 The vessel shall be protected by a permanently in stalled water-spraying system. Water shall be applied by means of sprinkler nozzles, monitor nozzles and water shield nozzles or a combination thereof. Vertical sides of superstructures shall be protected by spray nozzles. 3.1.2 The fixed water-spraying system shall provide protection for all outside vertical areas of hull, superstructures and deckhouses including foundations for water monitors, essential external equipment for fire fighting operations and external life rafts and lifeboats and rescue boats. Water spray may be omitted for bulwark and rails. 3.1.3 The arrangement for the water-spraying system shall be such that necessary visibility from the wheelhouse and the control station for remote control of the fire fighting water monitors can be maintained during the water spraying.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 84

Part 5 Chapter 10 Section 9

— instructions for use, testing and maintenance of the fire fighting installations and the equipment (or may be only referred to) — instructions for operation of the vessel during fire fighting — plan and records for periodically testing and drills.

2

3.1.5 The fixed water-spraying system shall have a capacity not less than 10 l/min/m of the areas to be 2 protected. For areas internally insulated to class A-60, a capacity of 5 l/min/m may be accepted. 3.1.6 The pumping capacity for the fixed water-spraying system shall be sufficient to deliver water at the required pressure for simultaneous operation of all nozzles in the total system. 3.1.7 The pumps for the fire fighting water monitors may also serve the water-spraying system, provided the pump capacity is increased by the capacity required for the water spraying system. A connection with shut-off valve is then to be fitted between the fire main for the monitors and the main pipeline for the water spraying system. Such arrangements shall allow for separate as well as simultaneous operation of both the fire fighting water monitors and the water spray system. 3.1.8 All pipes for the fixed water-spraying systems shall be protected against corrosion both externally and internally, by hot galvanizing or equivalent. Drainage plugs shall be fitted to avoid damages by freezing water. 3.1.9 The spray nozzles shall provide an effective and even distribution of water spray over the areas to be protected. The spray nozzles are subject to the Society's approval for their purpose.

3.2 Passive fire protection - class notation qualifier I+ only 3.2.1 Hull and superstructure shall be constructed of steel. External doors and hatches shall be of steel. Windows in boundary of superstructure/deckhouse, including bridge shall comply with A-0 class. External platforms and exposed piping systems shall be of steel.

4 Water monitor system 4.1 Capacities 4.1.1 The requirements for the various class notations are given in Table 1. Table 1 Water monitor system capacities Fire fighter (I) and (I+)

Class notation Number of monitors 3

Capacity of each monitor (m /h) Number of pumps 3

Total pump capacity (m /h) Length of throw (m)

1)

Height of throw (m)

2)

Fuel oil capacity in hours

3)

Fire fighter (II)

Fire fighter (III)

2

2

3

4

3

4

1200

3600

2400

1800

3200

2400

1-2

2-4

2-4

2400

7200

9600

120

180

150

180

150

50

110

80

110

90

24

96

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

96

Page 85

Part 5 Chapter 10 Section 9

3.1.4 The pipelines and nozzles shall be so arranged and protected that they will not be exposed to damage during the operations for which the vessel is intended.

For class notation qualifier I, measured horizontally from the monitor outlet to the mean impact area. For I+, II and III, measured horizontally from the mean impact area to the nearest part of the vessel when all monitors are in satisfactory operation simultaneously.

2)

Measured vertically from sea level to mean impact area at a horizontal distance of at least 70 m from the nearest part of the vessel.

3)

Capacity for continuous operation of all monitors, to be included in the total capacity of the vessel's fuel oil tanks.

4.2 Arrangement 4.2.1 The monitors shall play either forward or aft. The horizontal angular movement of each monitor shall be at least 90°, with minimum play across the vessels centre line of 30°. The necessary angular movement in the vertical direction is determined by the required height of throw of the water jet. The monitors shall be so positioned that they will have a free line for the water jet over the horizontal area covered. 4.2.2 At least two of the water monitors shall have a fixed arrangement making dispersion of the water jet possible. 4.2.3 The monitors shall be so arranged that the required length and height of throw can be achieved with all monitors operating simultaneously along the centre line of the vessel.

4.3 Monitor control 4.3.1 The activating and the manoeuvring of the monitors shall be remotely controlled. The remote control station shall be arranged in a protected control room with a good general view. The valve control shall be designed to avoid water hammer. 4.3.2 As a minimum, there shall be arranged two independent control systems such that a single failure will not disable more than 50% of the monitors installed. Failure in any remote control system shall initiate an alarm at the workstation from where the monitors are controlled. 4.3.3 Open and closed indication of remotely controlled valves, if fitted, shall be indicated at the remote control station. 4.3.4 Where an electrical control system is applied, each control unit shall be provided with overload and short-circuit protection, giving selective disconnection of the circuit in case of failure. Where a hydraulic or pneumatic control system is applied, the control power units shall be duplicated. 4.3.5 In addition to the remote control, local and manual control of each monitor shall be arranged. Guidance note: It is advised that the local and manual control devices are automatically disconnected when remote operation is applied. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.3.6 All shut-off and control equipment shall be clearly marked.

4.4 Design and support of monitors 4.4.1 The monitors and their foundations shall be capable of withstanding the loads to which they may be subjected on the open deck, dynamic loads resulting from the vessel's movement at sea, as well as the reaction forces from the water jet.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 86

Part 5 Chapter 10 Section 9

1)

5 Foam monitor system - class notation qualifier III 5.1 Capacities 5.1.1 In addition to the water monitors, the vessel shall be equipped with 2 foam monitors, each of a capacity not less than 5000 litres/minute with a foam expansion ratio of maximum 15 to 1. 5.1.2 The foam system, together with the arrangement and location of the monitors, shall give a height of throw at least 50 m above sea level when both monitors are used simultaneously with maximum foam generation. 5.1.3 The foam concentrate tank shall have capacity for at least 30 minutes of maximum foam generation from both foam monitors. When determining the necessary quantity of foam concentrate, the admixture is assumed to be 5%.

5.2 Arrangement 5.2.1 The arrangement shall comply with the same principles as given under [4.2.1]. 5.2.2 The foam generating system shall be of a fixed type with separate foam concentrate tank, foam-mixing unit and pipelines to the monitors. The water supply to the system may be taken from the main pumps for the water monitors. In such cases it may be necessary to reduce the main pump pressure to ensure correct water pressure for maximum foam generation.

5.3 Monitor control 5.3.1 The foam monitors shall be remotely controlled. This also concerns the operation of the valves necessary for control of water and foam concentrate. The remote control of the foam monitors shall be arranged from the same location as the control of the water monitors and the control system shall comply with the same principles as given in [4.3.2] to [4.3.4]. Local/manual control of each monitor shall also be arranged. 5.3.2 All shut-off and remote control equipment shall be clearly marked.

5.4 Monitor design 5.4.1 The foam monitors shall be of a design approved by the Society.

6 Pumps and piping 6.1 General 6.1.1 The arrangement shall be such that the water monitors will be able to deliver an even jet of water without pulsations of significance.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 87

Part 5 Chapter 10 Section 9

4.4.2 The monitors shall be able to give a solid water jet, so that the impact area will be concentrated and limited. The materials applied shall be selected with due regard to the corrosive properties of seawater and saline air. The monitors shall be of a design approved by the Society.

6.2 Pumps 6.2.1 The pumps for the fire fighting system and the machinery driving the pumps shall be adequately protected, and shall be so located that they will be easily accessible during operation and maintenance.

6.3 Seawater inlets and sea chests 6.3.1 Seawater suctions for fire fighting pumps shall not be arranged for other purposes. The seawater suction valve, the pressure valve and the pump motor shall be operable from the same position. Valves with nominal diameter exceeding 450 mm shall be power actuated as well as manually operable. 6.3.2 An interlock shall prevent start or engagement of the gear for the fire fighting pumps when the water inlet valve is closed and the pressure valve is open. Alternatively, warning by means of audible and visual alarm shall be given if starting of the fire fighting pumps or engaging gears for the pumps is carried out with the inlet valve closed and the pressure valve open. This alarm shall be given at all control positions for the start or engagement of the gear for the fire fighting pumps. 6.3.3 Suitable means for filling the water monitors' supply piping downstream of the pressure valves and up through the monitors whilst the pressure valves are in the closed position, shall be arranged. 6.3.4 Seawater inlets and sea chests shall be of a design ensuring an even and sufficient supply of water to the pumps. The location of the seawater inlets and sea chests shall be such that the water supply is not impeded by the ship's motions or by the water flow to and from bow thrusters, side thrusters, azimuth thrusters or main propellers. 6.3.5 Strums shall be fitted to the sea chest openings in the shell plating. The design maximum water velocity through the strum holes shall not exceed 2 m/s.

6.4 Piping systems 6.4.1 The piping system from the pumps to the water monitors shall be separate from the piping system to the hose connections required for the mobile fire fighting equipment. 6.4.2 The piping systems shall have arrangements to avoid overheating of the pumps at low delivery rates. 6.4.3 Suctions lines shall be designed to avoid cavitation in the water flow. The lines shall be as short and as straight as practicable. Pumps shall preferably be located below the water line. The net positive suction head (NPSH) for the pump system shall be designed according to the following formula: NPSH available – 1 meter water column > NPSH required For pumps located above water line an approved self-priming system shall be provided.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 88

Part 5 Chapter 10 Section 9

6.1.2 The requirements for pumping and piping systems given for systems covered by the main class, as well as the requirements for standard water extinguishing appliances and equipment for fire extinguishing on open decks given for main class, shall be complied with as far as applicable to systems fighting fires outside the vessel.

NPSH available is the ship specific available net suction head (expressed in meter water column - mwc) as function of the elevation of the pump in relation to the waterline deduced for the pressure losses in the sea chest and supply piping up to the inlet flange of the pump. NPSH required is the net suction head (expressed in mwc) required by the pump in question in order to prevent cavitation. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.4.4 All piping from seawater inlets to water monitors shall be internally protected against corrosion to a degree at least corresponding to hot galvanizing. Paint is accepted as external corrosion protection of piping exposed to weather. The part of pipes passing through fuel oil tanks shall have thickness as for ballast pipes passing through fuel oil tanks in accordance with Pt.4 Ch.6 Sec.6 Table 2. The corrosion protection of the pipes within the tank shall be to the same level as the internal tank structure, while internal corrosion protection may be excluded for this part. A system for drainage of the pipes within the fuel tank shall be arranged. Instruction shall be included in the operation manual for draining of these pipes upon completion of a fire fighting operation. 6.4.5 The piping layout shall be in accordance with good marine practice with large radius bends, and shall be satisfactorily protected against damage.

7 Mobile fire fighting equipment 7.1 Fire hydrants manifolds and hoses for external use 7.1.1 In addition to the fire hydrants required for onboard use, fire hydrant manifolds shall be provided on the port and starboard sides of the weather deck. The hose connections shall therefore point outwards. 7.1.2 Vessels with class notation qualifiers I and I+ shall have one fire hydrant manifold arranged on the port side and one on the starboard side, each with at least four (4) hose connections. 7.1.3 For vessels with class notation qualifier II the number of additional hose connections at each of the fire hydrant manifolds positioned on the port and starboard sides shall be not less than six (6). For vessels with class notation qualifier III the number shall be not less than eight (8). 7.1.4 In addition to the required number of hoses for onboard use, at least 8 × 15 m fire hoses of 50 mm diameter and four (4) combined 16 mm jet and water spray nozzles shall be kept onboard in a readily available position for vessels with class notation qualifiers I and I+. For those with class notation qualifier II, the number shall be increased to 12 hoses and 6 nozzles and for class notation qualifier III to 16 hoses and eight (8) nozzles. Table 2 Overview of additional hydrant manifolds, hose connections and nozzles Class notation qualifier

Number of fire hydrant manifolds Port

Starboard

Number of hose connections at each manifold

Total number of hose connections

I, I+

1

1

4

8

8

4

II

1 or 2

1 or 2

6

12

12

6

3

12

12

6

III

1 or 2

1 or 2

8

16

16

8

4

16

16

8

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Number of additional hoses

1)

Number of additional nozzles

2)

Page 89

Part 5 Chapter 10 Section 9

Guidance note:

Number of fire hydrant manifolds Port

Starboard

1)

Length 15 m, diameter 50 mm

2)

Combined 16 mm spray/jet

Number of hose connections at each manifold

Total number of hose connections

Number of additional hoses

1)

Number of additional nozzles

2)

7.1.5 The pressure in the fire hydrant manifold shall be not less than 2.5 bar and maximum 5 bar when tested as described in [1.4] with one length of hose fitted with a standard 16 mm nozzle fully open on each hose connection on one fire hydrant manifold. 7.1.6 The pumps for monitors and/or water spray system may be used for supply of water to the fire hydrant manifolds required by [7.1.1] provided pump capacity is increased so that all connected consumers can be simultaneously served. In such case connections with shut-off valves shall be fitted between the fire main for the monitors and/or water spray system in order to allow for separate as well as simultaneous operation of fire fighting water monitors and/or the water spray system as well as hoses connected to the fire hydrant manifolds. Valves shall be arranged for independent supply to the fire hydrant manifolds without having the monitor and/or the water spray in use. 7.1.7 Hoses and nozzles shall be of a design approved by the Society.

7.2 Foam generator 7.2.1 Vessels with class notation qualifier II and III shall have a mobile high expansion foam generator with 3 a capacity of not less than 100 m /minute for fighting of external fires. 7.2.2 Foam concentrate shall be stored in containers, each of about 20 litres, suitable for mobile use. The stored capacity of foam concentrate shall be sufficient for 30 minutes continuous foam production.

8 Fire fighter’s outfit 8.1 Number and extent of the outfits 8.1.1 Vessels with class notation qualifiers I and I+ shall have at least four (4) sets of fire fighter's outfits. 8.1.2 Vessels with class notation qualifier II shall have six (6) fire-fighter's outfits, and vessels with class notation qualifier III shall have eight (8) fire-fighter's outfits. 8.1.3 The equipment for the fire fighter’s outfits shall be as specified for main class except that each breathing apparatus shall have a total air capacity of at least 3600 litres including the spare cylinders.

8.2 Location of the fire fighter’s outfits 8.2.1 The fire fighter's outfits shall be placed in at least two separate fire stations of which one shall have access from the open deck. The entrance to the fire station shall be clearly marked. The room shall be arranged for ventilation and heating. 8.2.2 The arrangement of the fire station shall be such that all equipment will be easily accessible and ready for immediate use.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 90

Part 5 Chapter 10 Section 9

Class notation qualifier

8.3.1 A high pressure compressor with accessories suitable for recharging the breathing air cylinders, shall be installed onboard in the safest possible location. The capacity of the compressor shall be at least 75 litres/ minute. The air intake for the compressor shall be equipped with a filter.

9 Stability and watertight integrity 9.1 General requirements 9.1.1 For vessels with a length LLL of 24 m and above, the stability shall be assessed when the water monitors are in operation at full capacity in the most unfavourable direction with respect to stability. A calculation showing the point of balance between the reaction forces from the water monitors and the forces from the vessel's propulsion machinery and its side thrusters shall be presented. The monitor heeling moment shall be calculated based on the assumption in [9.1.2]. The criterion in [9.1.3] shall be complied with. 9.1.2 Monitor heeling moment The heeling force F from the water monitor(s) shall be assumed in the transverse direction, based on full capacity as given in Table 1. The monitor heeling arm a shall be taken as the vertical distance between the centre of side thruster(s) and the centre line of the monitor(s). 9.1.3 Criterion The monitor heeling lever, calculated as F · a/displacement, shall not exceed 0.5 times the maximum GZ corresponding to maximum allowable VCG. If the maximum GZ occurs after 30°, the GZ at 30° shall be used instead of the maximum GZ. Additional information on the monitor capacity, position, heeling force and moment as well as plotting the monitors' heeling lever on the GZ diagram of the most unfavourable loading conditions shall be included in the stability manual.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 91

Part 5 Chapter 10 Section 9

8.3 Compressed air supply

Symbols For symbols and definitions not defined in this chapter, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction These rules provide requirements for ships intended to operate in ice-infested waters with the main purpose of ice breaking for the intention of escort and ice management.

1.2 Scope The rules in this section give requirements for hull strength, stability and machinery, applicable to an icebreaker.

1.3 Application Vessels built in compliance with the requirement in this section and that are assigned a polar class notation PC(1) to PC(7) (see Pt.6 Ch.6 Sec.5), may be assigned the class notation Icebreaker.

2 General principles Vessels with class notation Icebreaker shall be able to carry out ice management and assist other vessels in ice conditions described in Pt.6 Ch.6 Sec.5 Table 1 and may make several consecutive attempts to break ice.

3 General arrangement 3.1 Bow form Ice knife may be required fitted in the icebreaking bow to avoid excessive beaching and submersion of the deck in the aft ship. This requirement will be based on consideration of design speed, stability and the freeboard. See Figure 1. Vessels with class notation Icebreaker shall have a bow shape so that the bow will ride up on the ice when encountering pressure ridges or similar ice features which will not break during the first ramming. Guidance note: At the UIWL the angle between the stem and the waterline should be 22°-35°. The bow-lines in the fore body below the waterline should be parallel to the stem. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2 Stem and stern region The stem reinforcement in Pt.6 Ch.6 Sec.5 [5.8] shall be extended vertically from the keel to the horizontal line x m above the UIWL, and horizontally to a line 0.06 L aft of the stem line or 0.125 B outboard from the centre line, whichever is reached first. See Figure 1. The fore boundary of the stern region shall be at least 0.04 L fore of the aftermost point where the hull lines are parallel to the centre line at upper ice waterline (UIWL), see Figure 1.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 92

Part 5 Chapter 10 Section 10

SECTION 10 ICEBREAKER

Part 5 Chapter 10 Section 10 Figure 1 Stem and hull area extents

3.3 Position of collision bulkhead The distance from the vertical ram bow, i.e. forward ice knife, to the collision bulkhead shall be at least 2s, in m, where s is the frame spacing. See Figure 2.

Figure 2 Position of collision bulkhead

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 93

— Floatability and stability calculations showing that, with the ship fully loaded to summer draught on even keel, flooding of the space forward of the collision bulkhead will not result in any other compartments being flooded, nor in an unacceptable loss of stability.

4 Structural design 4.1 Materials 4.1.1 Material in fore ship substructure in vessels with class notations DAT(t) shall be of class III. 4.1.2 Within 0.2 L aft of amidships and 0.3 L forward of amidships for vessel with class notations DAT(t), material classes shall be according to Pt.6 Ch.6 Sec.4 Table 4. Where there is overlap of material class requirement of Pt.3 Ch.3 Sec.1, the class giving the highest steel grade shall be applied.

5 Loads 5.1 Hull area factors The area factors (AF) reflecting the relative magnitude of the ice load expected in that area for each PC polar class notation are listed in Table 1, Table 2 and Table 3. Table 1, Table 2 and Table 3 in this section shall be used as an alternative to Pt.6 Ch.6 Sec.5 Table 6, Pt.6 Ch.6 Sec.5 Table 7 and Pt.6 Ch.6 Sec.5 Table 8, respectively. Table 1 Hull area factors (AF) for ships with class notation Icebreaker Hull area

Area

Bow (B) Bow intermediate (BI)

Midbody (M)

Stern (S)

Polar class PC(1)

PC(2)

PC(3)

PC(4)

PC(5)

PC(6)

PC(7)

All

B

1.00

1.00

1.00

1.00

1.00

1.00

1.00

Icebelt

BIi

0.90

0.85

0.85

0.85

0.85

1.00*

1.00*

Lower

BIl

0.70

0.65

0.65

0.65

0.65

0.65

0.65

Bottom

BIb

0.55

0.50

0.45

0.45

0.45

0.45

0.45

Icebelt

Mi

0.70

0.65

0.55

0.55

0.55

0.55

0.55

Lower

Ml

0.50

0.45

0.40

0.40

0.40

0.40

0.40

Bottom

Mb

0.30

0.30

0.25

0.25

0.25

0.25

0.25

Icebelt

Si

0.95

0.90

0.80

0.80

0.80

0.80

0.80

Lower

Sl

0.55

0.50

0.45

0.45

0.45

0.45

0.45

Bottom

Sb

0.35

0.30

0.30

0.30

0.30

0.30

0.30

Notes: * See Pt.6 Ch.6 Sec.5 [4.1.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 94

Part 5 Chapter 10 Section 10

In the case where the maximum distance xc from the perpendicular FE to the collision bulkhead as specified in Pt.3 Ch.2 Sec.2 [4] is exceeded, the following shall be submitted:

Hull area

Area

Bow (B) Bow intermediate (BI)

Midbody (M)

Stern (S)

Polar class PC(1)

PC(2)

PC(3)

PC(4)

PC(5)

PC(6)

PC(7)

All

B

1.00

1.00

1.00

1.00

1.00

1.00

1.00

Icebelt

BIi

0.90

0.85

0.85

0.80

0.80

1.00*

1.00*

Lower

BIl

0.70

0.65

0.65

0.65

0.55

0.55

0.50

Bottom

BIb

0.55

0.50

0.50

0.45

0.35

0.30

0.25

Icebelt

Mi

0.70

0.65

0.55

0.55

0.55

0.55

0.55

Lower

Ml

0.55

0.45

0.40

0.40

0.40

0.40

0.40

Bottom

Mb

0.30

0.30

0.25

0.25

0.25

0.25

0.25

Icebelt

Si

0.95

0.90

0.80

0.80

0.80

0.80

0.80

Lower

Sl

0.70

0.65

0.60

0.60

0.60

0.60

0.60

Bottom

Sb

0.35

0.30

0.30

0.30

0.30

0.30

0.30

Notes: * See Pt.6 Ch.6 Sec.5 [4.1.3].

Table 3 Hull area factors (AF) for ships with class notation Icebreaker intended to operate astern Hull area

Area

Bow (B) Bow intermediate (BI)

Midbody (M)

Stern intermediate (SI)**

Stern (S)

Polar class PC(1)

PC(2)

PC(3)

PC(4)

PC(5)

PC(6)

PC(7)

All

B

1.00

1.00

1.00

1.00

1.00

1.00

1.00

Icebelt

BIi

0.90

0.85

0.85

0.85

0.85

1.00*

1.00*

Lower

BIl

0.70

0.65

0.65

0.65

0.65

0.65

0.65

Bottom

BIb

0.55

0.50

0.45

0.45

0.45

0.45

0.45

Icebelt

Mi

0.70

0.65

0.55

0.55

0.55

0.55

0.55

Lower

Ml

0.50

0.45

0.40

0.40

0.40

0.40

0.40

Bottom

Mb

0.30

0.30

0.25

0.25

0.25

0.25

0.25

Icebelt

SIi

0.90

0.85

0.85

0.85

0.85

1.00*

1.00*

Lower

SIl

0.70

0.65

0.65

0.65

0.65

0.65

0.65

Bottom

SIb

0.55

0.50

0.45

0.45

0.45

0.45

0.45

Icebelt

Si

1.00

1.00

1.00

1.00

1.00

1.00

1.00

Lower

Sl

0.77

0.72

0.72

0.72

0.72

0.72

0.72

Bottom

Sb

0.61

0.55

0.50

0.50

0.50

0.50

0.50

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 95

Part 5 Chapter 10 Section 10

Table 2 Hull area factors (AF) for ships with class notation Icebreaker with thrusters/podded propulsion

Area

Polar class PC(1)

PC(2)

PC(3)

PC(4)

PC(5)

PC(6)

PC(7)

Notes: * See Pt.6 Ch.6 Sec.5 [4.1.3]. ** The stern intermediate region, if any, for vessels intended to operate astern shall be defied as the region forward of stern region to section 0.04 L forward of WL angle = 0 degrees at UIWL (see definition of bow intermediate in Figure 1 in Pt.6 Ch.6 Sec.5).

6 Longitudinal hull girder strength Longitudinal strength criteria in Pt.6 Ch.6 Sec.5 Table 10 shall be satisfied with η = 0.6.

7 Hull local scantlings 7.1 General Local scantlings shall be checked according to requirement in Pt.6 Ch.6 Sec.5 considering the area factors AF listed in Table 1, Table 2 and Table 3 in [5.1].

7.2 Overall strength of substructure in fore ship 7.2.1 The overall strength of substructure in the fore ship shall be evaluated. Loads to be applied shall be based on a case-by-case basis. 7.2.2 For strength assessment acceptance criteria AC-II to be applied as given in Pt.3 Ch.7.

8 Stability 8.1 General 8.1.1 Vessels with a freeboard length LLL of 24 meters and above and class notation Icebreaker shall comply with the requirements of Pt.3 Ch.15 and IMO Polar Code Chapter 4 Subdivision and Stability, as well as the requirements of this subsection.

8.2 Intact stability 8.2.1 The initial metacentric height GM shall not be less than 0.5 m.

8.3 Requirements for watertight integrity 8.3.1 As far as practicable, tunnels, ducts or pipes which may cause progressive flooding in case of damage, shall be avoided in the damage penetration zone. If this is not possible, arrangements shall be made to prevent progressive flooding to volumes assumed intact. Alternatively, these volumes shall be assumed flooded in the damage stability calculations.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 96

Part 5 Chapter 10 Section 10

Hull area

9 Machinery 9.1 Propeller ice interaction Ice interaction loads in this section are intended to cover all typical operational ice loads for icebreakers and shall be applied in addition to, or instead of those specified in Pt.6 Ch.6 Sec.5 [11].

9.2 Design ice loads for open propeller 9.2.1 Maximum backward blade force, Fb in kN, for open propellers when D < Dlimit:

when D ≥ Dlimit:

where Dlimit, in m, is given as:

where:

Sice

= Ice strength index for blade ice force and shall be taken as 1.2 for PC(1) to PC(3). See Pt.6 Ch.6 Sec.5 [11.2] for requirements for other polar class notations.

Definition of the other parameters is given in Pt.6 Ch.6 Sec.5 [11.2] and Pt.6 Ch.6 Sec.5 [11.3]. 9.2.2 Axial loads on propeller hub Axial ice loads on pulling type propeller hub shall be calculated assuming a nominal ice crushing pressure of 8 MPa for multi-year ice (PC(1) to PC(3)) and 4 MPa for first-year ice (PC(6) and PC(7)). For PC(4) and PC(5) an intermediate value of 6 MPa shall be used. Propeller hub and affected parts in the propeller and shaft line shall have safety factor 1.5 against yield strength. Guidance note: A method for calculating these loads is described in DNVGL-CG-0041. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 97

Part 5 Chapter 10 Section 10

8.3.2 The scantlings of tunnels, ducts, pipes, doors, staircases, bulkheads and decks, forming watertight boundaries, shall be adequate to withstand pressure heights corresponding to the deepest equilibrium waterline in damaged condition.

It is assumed that the force that causes blade failure typically reduces when moving from the propeller centre towards the leading and trailing edges. At a certain distance from the blade centre of rotation the maximum spindle torque will occur. This maximum spindle torque in kNm, shall be defined by an appropriate stress analysis or using equation below:

where:

Cspex = Csp ∙ Cfex Csp = ratio between the distance from spindle axis to the position giving maximum spindle torque, and the distance between spindle axis and leading or trailing edge, all at 0.8 R chord

Cfex cLE0.8 cTE0.8 Fex

= ratio between load at position of maximum spindle torque and blade failure load = leading edge portion of the chord length at 0.8 R = trailing edge portion of the chord length at 0.8 R = blade failure load, in kN, as defined in Pt.6 Ch.6 Sec.5 [11.6].

If the values Csp and Cfex are not known, the following approximation may be used:

If the values Cspex is below 0.3, a value of 0.3 shall be used for Cspex.

9.3 Design ice loads for propulsion line Dynamic torsional analysis of ice impacts on the propeller shall be carried out for all propulsion plants. The propeller ice torque excitation for shaft line transient dynamic analysis (time domain) is defined as a sequence of blade impacts which are of half sine shape and occur at the blade. The torque due to a single blade ice impact as a function of the propeller rotation angle, in kNm, is then defined as:

when φ rotates from 0 to

i

plus integer revolutions, or: Q(φ) = 0

when φ rotates from

i

to 360 plus integer revolutions.

Where: = rotation angle starting when the first impact occurs φ Qmax = maximum propeller ice torque (also referred to as Tmax in Pt.6 Ch.6 Sec.5). The parameters Cq and i are given in Table 4. in propeller rotation angle.

i

is the duration of propeller blade/ice interaction expressed

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 98

Part 5 Chapter 10 Section 10

9.2.3 Maximum spindle torque for controllable pitch propellers The maximum spindle torque Qsex due to a blade failure load acting at 0.8R shall be determined.

Torque excitation

Propeller-ice interaction

C

i q

(deg.)

Z=3

Z=4

Z=5

Z=6

Excitation case 1

Single ice block

1.0

90

90

72

60

Excitation case 2

Single ice block

1.0

135

135

135

135

Excitation case 3

Two ice blocks (phase shift 360 deg/(2·Z)

0.5

45

45

36

30

Excitation case 4

Single ice block

1.0

45

45

36

30

The total ice torque is obtained by summing the torque of single blades, taking into account the phase shift 360 deg/Z. At the beginning and at the end of the milling sequence (within calculated duration) linear ramp functions shall be used to increase Cq to its maximum within one propeller revolution and vice versa to decrease it to zero. The number of propeller revolutions during a milling sequence shall be obtained from the formula: NQ = 2 Hice The number of impacts is Z · NQ for blade order excitation. The dynamic simulation shall be performed for all excitation cases at bollard condition with corresponding propeller speed and maximum available output of the engine.

9.4 Fatigue evaluation of propulsion line For the evaluation of fatigue, the number of load cycles shall be multiplied by a factor 3 to account for the assumed operational profile of icebreakers:

Definition of parameters is given in Pt.6 Ch.6 Sec.5 [12.1].

9.5 Steering system Additional fast acting torque relief arrangements (acting at 15% higher pressure than set pressure of safety valves) shall be fitted in order to provide effective protection of the rudder actuator in case of the rudder being pushed rapidly hard over against the rudder stops. The rudder turning speed to be assumed for each ice class is shown in Table 5. The arrangement shall be designed such that steering capacity can be speedily regained. Table 5 Turning speeds for dimensioning of fast acting torque relief arrangements Ice class Turning speeds in deg/s

PC(1) and PC(2)

PC(3) to PC(5)

PC(6) and PC(7)

40

20

15

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 99

Part 5 Chapter 10 Section 10

Table 4

Symbols For symbols and definitions not defined in this chapter, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for towing and/or escort services in harbour and open waters and pushing of floating structures.

1.2 Scope 1.2.1 The following subjects are covered in this section: — design and testing requirements for towing equipment — hull arrangement and supporting structure — stability and watertight integrity.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements given in [1] to [5] may be given the class notation Tug. 1.3.2 Vessels built in compliance with the relevant requirements given in [1] to [6] may be given the class notation Escort tug with the qualifiers as specified in Table 1.

1.4 Class notations Ships built in compliance with the requirements as specified in Table 1 may be assigned the additional notations and qualifiers as given below. Table 1 Additional class notations for tugs and escort vessels Class Notation

Qualifier

Purpose

Application

Tug Mandatory: No Design requirements: [1] to [5]



Towing of other vessels by towlines

FiS survey requirements: Pt.7 Ch.1 Sec.2, Pt.7 Ch.1 Sec.3, Pt.7 Ch.1 Sec.4 and Pt.7 Ch.1 Sec.6 [34]

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 100

Part 5 Chapter 10 Section 11

SECTION 11 TUGS AND ESCORT VESSELS

Qualifier

F

Purpose

Application

Steering and manoeuvring operations of other vessels by towlines Escort rating numbers based on full scale test

N

Escort tug Mandatory: No

O

Design requirements: [1] to [6] FiS survey requirements:

Steering and manoeuvring operations of other vessels by towlines

One of the qualifiers F, N or O is mandatory

Escort rating numbers based on numerical calculations

Only one of the qualifiers F, N or O may be assigned

Steering and manoeuvring operations of other vessels by towlines Escort rating numbers established by another classification society (FS, t, v) are escort rating numbers, where:

Pt.7 Ch.1 Sec.2, Pt.7 Ch.1 Sec.3, Pt.7 Ch.1 Sec.4 and Pt.7 Ch.1 Sec.6 [34]

FS indicates maximum transverse steering pull in ton, exerted by the escort tug on the stern of the assisted vessel (FS, t, v)

t is the time in seconds required for the change of the tug's position from one side to the corresponding opposite side

Mandatory qualifier Maximum two sets of escort rating numbers may be assigned

v is the speed in knots at which this pull may be attained

1.5 Testing requirements 1.5.1 Workshop testing Towing hook and quick release: Towing hooks with a mechanical quick release, the movable towing arm and other load transmitting elements shall be subjected to a test force PL with the aid of an approved testing facility. In connection with this test, the quick release shall be tested likewise; the release force shall be measured and is not to exceed 150 N, see [3.5.3]. When towing hooks are provided with a pneumatic quick release, both the pneumatic and the mechanical quick release required by [3.5.4] shall be tested. Also towing hooks with a hydraulic quick release shall be tested, but the quick release itself need not be subjected to the test load. If a cylinder tested and approved by the Society is employed as a loaded gear

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 101

Part 5 Chapter 10 Section 11

Class Notation

Certification and stamping of towing hook: Following each satisfactory testing at manufacturer's, a test certificate will be issued by the attending surveyor and shall be handed on board, together with the towing hook. Towing winches: The winch power unit shall be subjected to a test bed trial at the manufacturer's. A works test certificate shall be presented on the occasion of the final inspection of the winch, see [1.5.2] under Towing hooks on board. Components exposed to pressure shall be pressure-tested to a test pressure PD of: PD = 1.5 P where:

P = admissible working pressure or opening pressure of the safety valves, in bar. However, with working pressures exceeding 200, the test pressure need not be higher than P + 100.

Tightness tests shall be carried out at the relevant components. Upon completion, towing winches shall be subjected to a final inspection and an operational test to the rated load. The hauling speed shall be determined during an endurance test under the rated tractive force. During these trials, in particular the braking and safety equipment shall be tested and adjusted. The brake shall be tested to a test load equal to the rated holding capacity, but at least equal to the bollard pull. If manufacturers do not have at their disposal the equipment required, a test confirming the design winch capacity, and including adjustment of the overload protection device, may be carried out after installation on board, see [1.5.2]. In that case only the operational trials without applying the prescribed loads will be carried out at the manufacturers. Accessory towing gear components and towlines: Accessories subjected to towing loads, where not already covered by [1.5.1], are generally to be tested to test force PL at the manufacturer. For all accessories certificates, CG 3, and for the towline, CG 4, shall be submitted. The Society reserve the right of stipulating an endurance test to be performed of the towing gear components, where considered necessary for assessment of their operability. 1.5.2 On board testing Towing gear testing requirements: The installed towing gear shall be tested on the tug using the bollard pull (BP) test to simulate the towline pull.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 102

Part 5 Chapter 10 Section 11

component, during the load test the cylinder may be replaced by a load transmitting member not pertaining to the gear, the operability of the gear being restored subsequently. The operability of the quick release shall be proved with the towline loosely resting on the hook.

— the ability for the arrangement and equipment to operate within the specified limitations, towline paths, towline sectors etc. specified by the arrangement drawing — the correct function of the normal operation modes — the correct function of the emergency operation modes, including emergency release mechanism and dead ship operations. Bollard pull test: In general a BP test should be carried out before entering into service of the vessel. The test can be witnessed and certified by DNV GL. Based upon the results of the test a bollard pull certificate will be issued. The expected BP may be preliminarily applied for design approval purposes prior to sea trial. If sea trial reveals that the expected BP is exceeded by more than 10%, such design approvals shall be re-considered. The following test procedure should be adhered to and possible deviations shall be recorded in the bollard pull certificate: 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16)

Approved test programme shall be submitted prior to the testing. During testing of continuous static BP the main engine(s) shall be run at the manufacturer's recommended maximum continuous rating (MCR). During testing of overload pull, the main engines shall be run at the manufacturer's recommended maximum rating that can be maintained for a minimum of 1 hour. The overload test may be omitted. The propeller(s) fitted when performing the test shall be the propeller(s) used when the vessel is in normal operation. All auxiliary equipment such as pumps, generators and other equipment, which are driven from the main engine(s) or propeller shaft(s) in normal operation of the vessel shall be connected during the test. The vessel shall be trimmed at even keel or at a trim by stern not exceeding 2% of the vessel's length. The vessel shall be able to maintain a fixed course for not less than 10 minutes while pulling as specified in items 2 or 3 above. The test shall be performed with a fair wind speed not exceeding 5 m/s. The co-current at the test location shall not exceed 1 knot. The load cell used for the test shall be approved by the Society and be calibrated at least once a year. The accuracy of the load cell shall be ± 2% within a temperature range and a load range relevant for the test. An instrument giving a continuous read-out and also a recording instrument recording the bollard pull graphically as a function of the time shall both be connected to the load cell. The arrangement of bollard, towline and load cell shall ensure a force reading in horizontal direction by means of minimizing the influence from friction and force components in vertical direction. The figure certified as the vessel's continuous static BP shall be the towing force recorded as being maintained without any tendency to decline for a duration of not less than 10 minutes. Certification of BP figures recorded when running the engine(s) at overload, reduced r.p.m. or with a reduced or an increased number of engines or propellers operating can be given and noted on the certificate. The angular position of turn able propulsion devices shall be recorded. Both the load cell reading, engine power, and other essential parameters shall be continuously available to the surveyor. The recorded load cell readings shall be made available to the surveyor immediately upon completion of the test.

Towing hooks on board: For all towing hooks (independent of the magnitude of the test force PL, as defined in Table 3), the quick release shall be tested with an upward towline direction against the horizontal line of 60° or 45° respectively as outlined in [3.5.5]. If the towline will never be operated in such upward direction due to the tug is equipped with a towrope guidance at stern, then this release test may be carried out in the maximum occurring upward direction.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 103

Part 5 Chapter 10 Section 11

The winch and other equipment made mandatory in this section shall be function tested according to approved procedure in order to verify:

The surveyor certifies the initial on board test by an entry into the test certificate for towing hooks. Towing winches on board: After installation on board, the safe operation of the winch(es) from all control stands shall be checked. It shall be proved that for both cases a) with the drum brake engaged and b) during hoisting and pay out, the emergency release mechanism for the drum operates well under both normal and dead ship operation modes. These checks may be combined with the bollard pull test. The towing winch shall be subjected to a trial during the bollard pull test to a test load corresponding to the holding power of the winch.

2 Hull arrangement and strength 2.1 Draught for scantlings 2.1.1 For determining the scantlings of strength members based on the ship's draught, the latter shall not be taken less than 0.85 D.

2.2 Fore body, bow structure 2.2.1 On tugs for ocean towage, strengthening in way of the fore body, i.e. stringers, tripping brackets etc. shall conform to the indications given in Pt.3 Ch.10 Sec.1. The stringers shall be effectively connected to the collision bulkhead. Depending on the type of service expected, additional strengthening may be required. 2.2.2 For harbour tugs frequently engaged in berthing operations, the bow shall be suitably protected by fendering and be structurally strengthened. 2.2.3 The bulwark shall be arranged with an inward inclination in order to reduce the probability and frequency of damages. Square edges shall be chamfered. 2.2.4 The bow structure of tugs in pushing operation for maneuvering at narrow, sheltered waters shall be strengthened as noted in [2.2.5], [2.2.6] and [2.2.7]. 2.2.5 Forward of the collision bulkhead stringers shall be arranged on the ship's side not more than 2 m apart. The stringers shall be connected to the collision bulkhead by brackets forming gradual transition to the bulkhead. 2.2.6 The design push force and the extent of the push force area shall be marked on the foreship drawings. Based on this design push force times a dynamic factor of 1.3 and based on net scantlings, the stresses in the supporting structures shall not exceed: — Normal stress = — Shear stress = — Equivalent stress = 2.2.7 The frames shall be connected to the stringers by lugs or brackets at every frame. 2.2.8 For pusher tugs for inland navigation, see rules for inland navigation vessels DNVGL-RU-INV Pt.5 Ch.6.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 104

Part 5 Chapter 10 Section 11

In addition, the towing hook shall be load tested with a load equal to BP.

2.3.1 The side structure of areas frequently subjected to impact loads shall be reinforced by increasing the section modulus of side frames by 20%. Besides, fendering may be necessary to reduce indenting damages of the shell plating. 2.3.2 A continuous and suitable strong fender shall be arranged along the upper deck, extending the whole length of the vessel.

2.4 Engine room casing, superstructures and deckhouses 2.4.1 The gross plate thickness of the casing walls and casing tops shall not be less than 5 mm. The gross thickness of the coamings shall not be less than 6 mm. The coamings shall extend to the lower edges of the beams. 2.4.2 The stiffeners of the casing shall be connected to the beams of the casing top and shall extend to the lower edge of the coamings. 2.4.3 The following requirements shall be observed for superstructures and deckhouses of tugs assigned for the restricted services areas R0 to R4 or for unlimited range of service: — The plate thickness of the external boundaries of superstructures and deckhouses shall be increased by 1 mm above the thickness as required in Pt.3 Ch.6 Sec.8 [3]. — The section modulus of stiffeners shall be increased by 50% above the values as required in Pt.3 Ch.6 Sec.8 [3].

2.5 Foundations of towing gear 2.5.1 The substructure of the towing hook attachment and the foundations of the towing winch, and of any guiding elements such as towing posts or fairleads, where provided, shall be thoroughly connected to the ship's structure, considering all possible directions of the towline, see [3.5.5]. 2.5.2 The stresses in the supporting structure, foundations and fastening elements shall not exceed the permissible stresses shown in Table 2 (based on the gross thickness), assuming a load equal to the test load of the towing hook in case of hook arrangements, see [3.3.3], and a load of the winch holding capacity in case of towing winches, see also [3.5.5] and [3.7.3]. Table 2 Permissible stresses Type of stress

Permissible stress

Axial and bending tension and axial and bending compression with box type girders and tubes

σ = 0.83 ReH

Axial and bending compression with girders of open cross sections or with girders consisting of several members

σ = 0.72 ReH

Shear

τ = 0.48 ReH σvm = 0.85 ReH

Equivalent stress

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 105

Part 5 Chapter 10 Section 11

2.3 Side structure

2.6.1 On tugs for ocean towage, the deck, particularly in the forward region, shall be suitably protected or strengthened against sea impact. 2.6.2 Depending on the towline arrangement, the deck in the aft region shall be strengthened (beams, plate thickness), if considerable chafing and/or impact shall be expected. See also [3.3.2].

2.7 Stern frame 2.7.1 The cross sectional area of a solid stern frame shall be 20% greater than required according to Pt.3 Ch.10 Sec.6 [2]. For fabricated stern frames, the thickness of the propeller post plating shall be increased by 20% compared to the requirements given in Pt.3 Ch.10 Sec.6 [2]. The section modulus Z1 of the sole piece shall be increased by 20% compared to the modulus determined according to Pt.3 Ch.14 Sec.1 [5].

3 Systems and equipment 3.1 Anchoring and mooring equipment 3.1.1 Equipment number Tugs shall have anchoring and mooring equipment corresponding to its equipment number, see Pt.3 Ch.11 Sec.1 [3.1]. The term 2 BH in the formula may, however, be substituted by: 2(aB + Σ hi bi) where:

bi = breadth, in m, of the widest superstructure or deckhouse of each tier having a breadth greater than B/4.

3.1.2 General requirements For tugs with restricted service the equipment specified in Pt.3 Ch.11 Sec.1 Table 1 may be reduced in accordance with Pt.3 Ch.11 Sec.1 Table 3. No reductions are given for class notations R0 and R1. For tugs in the service range RE, see rules for classification: DNVGL-RU-INV. For tugs engaged only in berthing operations, one anchor is sufficient, if a spare anchor is readily available on land. 3.1.3 Tugs operating as pusher units The anchoring equipment for tugs operating as pusher units will be considered according to the particular service. Normally, the equipment is intended to be used for anchoring the tug alone, the pushed unit being provided with its own anchoring equipment.

3.2 Steering gear/steering arrangement 3.2.1 Steering stability Steering stability, i.e. stable course maintaining capability of the tug, shall be ensured under all normally occurring towing conditions. Rudder size and rudder force shall be suitable in relation to the envisaged towing conditions and speed.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 106

Part 5 Chapter 10 Section 11

2.6 Deck structure

For tugs exceeding 500 gross tons the time required to put the rudder from 35° port to 30° starboard or vice versa shall not exceed 28 seconds when the vessel is running ahead at maximum service speed. Special rudder arrangements may be considered in the particular case, see also [3.2.3]. 3.2.3 Special steering arrangements Steering units and arrangements not explicitly covered by the rules mentioned above, and combinations of such units with conventional rudders, will be considered from case to case. 3.2.4 Tugs operating as pusher units For tugs operating as pusher units, the steering gear shall be designed to guarantee satisfying steering characteristics in both cases, tug alone and tug with pushed object.

3.3 Towing gear/towing arrangement 3.3.1 Design standard The equipment shall meet the requirements in this section. Alternatively equipment complying with recognized standard may be accepted on a case-by-case basis, provided such specifications give equivalence to the requirements of this section and is fulfilling the intention. Towing arrangement drawing with the content listed under documentation requirement in Sec.1 [4] shall be posted on bridge. 3.3.2 General requirements The towing gear shall be arranged in such a way as to minimise the danger of capsizing; the towing hook/ working point of the towing force shall be placed as low as practicable, see [5.1]. With direct-pull (hook-towline), the towing hook and its radial gear shall be designed such as to permit adjusting to any foreseeable towline direction. The attachment point of the towline shall be arranged closely behind the centre of buoyancy. On tugs equipped with a towing winch, the arrangement of the equipment shall be such that the towline is led to the winch drum in a controlled manner under all foreseeable conditions (directions of the towline). Towline protection sleeves or other adequate means shall be provided to prevent the directly pulled towlines from being damaged by chafing/abrasion. 3.3.3 Definition of loads The design force Tb, in kN, corresponds to the towline pull (or the bollard pull, if the towline pull is not defined) as specified. The design force may be verified by a bollard pull test, see [1.5.2]. The test force PL is used for dimensioning as well as for testing the towing hook and connected elements. The test force is related to the design force as shown in Table 3. Table 3 Design force Tb and test force PL Design force Tb

Test force PL kN

kN T

b

≤ 500

2.00 Tb

500 < Tb ≤ 1 500

T

1 500 < Tb

b

+ 500

1.33 Tb

The minimum breaking force of the towline is based on the design force, see [3.6.3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 107

Part 5 Chapter 10 Section 11

3.2.2 Rudder movement

For forces at the towing hook foundation see [3.5.5].

3.4 Materials for equipment 3.4.1 Towing hook with attachment shall be made of rolled, forged or cast steel in accordance with Pt.2. 3.4.2 Towing winch materials shall comply with relevant specifications given in Pt.2. 2

3.4.3 For forged and cast steel with minimum specified tensile strength above 650 N/mm , specifications of chemical composition and mechanical properties shall be submitted for approval for the equipment in question. 3.4.4 Plate material in welded parts shall be of the grades as given in Pt.3 Ch.11 Sec.1 Table 11. 3.4.5 When ReH is greater than 80% of Rm, the following value shall be used as ReH in calculations for structural strength as given in [3.7]: ReH = min(ReH; 0.8 Rm) 3.4.6 Fabrication of towing hook with attachments is generally to be in accordance with the Society's document DNVGL-ST-0378 Standard for offshore and platform lifting appliances.

3.5 Towing hook and quick release 3.5.1 The towing hook shall be fitted with an adequate device guaranteeing slipping, i.e. emergency release, of the towline in case of an emergency. Slipping shall be possible from the bridge as well as from at least one other place in the vicinity of the hook itself, from where in both cases the hook can be easily seen. 3.5.2 The towing hook shall be equipped with a mechanical, hydraulic or pneumatic quick release. The quick release shall be designed such as to guarantee that unintentional slipping is avoided. 3.5.3 A mechanical quick release shall be designed such that the required release force under test force PL does not exceed neither 150 N at the towing hook nor 250 N when activating the device on the bridge. In case of a mechanical quick release, the releasing rope shall be guided adequately over sheaves. If necessary, slipping should be possible by downward pulling, using the whole body weight. 3.5.4 Where a pneumatic or hydraulic quick release is used, a mechanical quick release shall be provided additionally. 3.5.5 Dimensioning of towing hook and towing gear The dimensioning of the towing gear is based on the test force PL, see [3.3.3]. The towing hook, the towing hook foundation, the corresponding substructures and the quick release shall be designed for the following directions of the towline: — For a test force PL ≤ 500 kN: — in the horizontal plane, directions from abeam over astern to abeam — in the vertical plane, from horizontal to 60° upwards. — For a test force PL > 500 kN: — in the horizontal plane, as above — in the vertical plane, from horizontal to 45° upwards.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 108

Part 5 Chapter 10 Section 11

The winch holding capacity shall be based on the minimum breaking force, see [3.7.3], the rated winch force is the hauling capacity of the winch drive when winding up the towline, see [1.5.1].

For the towing hook foundation it shall be additionally proven that the permissible stresses given in Table 2 are not exceeded assuming a load equal to the minimum breaking force Fmin, in kN, of the towline.

3.6 Towlines 3.6.1 Towline materials shall correspond to the requirements given in Pt.3 Ch.11 Sec.1 [7]. All wire ropes should have as far as possible the same lay. 3.6.2 The length of the towline shall be chosen according to the tow formation (masses of tug and towed object), the water depth and the nautical conditions. Regulations of flag state authorities shall be observed. 3.6.3 The required minimum breaking force Fmin, in kN, of the towline shall be determined by the following formula:

where:

K

Tb

= Utility factor, to be taken as: K = 2.5

for Tb ≤ 200 kN

K = 2.625 −

for 200 kN < Tb < 1000 kN

K = 2.0

for Tb ≥ 1000 kN

= Design force, in kN, as defined in [3.3.3].

3.6.4 For ocean towages, at least one spare towline with attachments shall be available on board.

3.7 Towing winch 3.7.1 Arrangement and control The towing winch, including towline guiding equipment, shall be arranged such as to guarantee safe guiding of the towline in all directions according to [3.5.5]. The winch shall be capable of being safely operated from all control stands. Apart from the control stand on the bridge, at least one additional control stand shall be provided on deck. From each control stand the winch drum shall be freely visible; where this is not ensured, the winch shall be provided with a self-rendering device. Each control stand shall be equipped with suitable operating and control elements. The arrangement and the working direction of the operating elements shall be analogous to the direction of motion of the towline. Operating levers shall, when released, automatically return to the stop position. They shall be capable of being secured in the stop position. It is recommended that, on vessels for ocean towage, the winch is fitted with equipment for measuring the pulling force in the towline. If, during normal operating conditions, the power for the towing winch is supplied by a main engine shaft generator, another generator shall be available to provide power for the towing winch in case of main engine or shaft generator failure.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 109

Part 5 Chapter 10 Section 11

Assuming the test force PL acting in any of the directions described in [3.5.5], the permissible stresses in the towing equipment elements defined above are not to exceed the values shown in Table 2.

1) 2) 3) 4) 5) 6) 7)

The towline shall be fastened on the winch drum by a breaking link. The winch drum shall be capable of being declutched from the drive. The diameter of the winch drum shall be not less than 14 times the towline diameter. However, for all towline types, the towline bending radius should not be less than specified by the towline manufacturer. To ensure security of the rope end fastening, at least three (3) dead turns shall remain on the drum. At the ends, drums shall have disc sheaves whose outer edges shall surmount the top layer of the rope at least by 2.5 rope diameters, if no other means is provided to prevent the rope from slipping off the drum. If a multi-drum winch is used, then each winch drum shall be capable of independent operation. Items 3 to 4 above are not applicable to towlines of austenitic steels and fibre ropes. In case these towline materials are utilized, dimensioning of the winch drum is subject to the Society’s approval.

3.7.3 Holding capacity/dimensioning The holding capacity of the towing winch (towline in the first layer) shall correspond to 80% of the minimum breaking load Fmin of the towline. When dimensioning the towing winch components, which - with the brake engaged - are exposed to the pull of the towline (rope drum, drum shaft, brakes, foundation frame and its fastening to the deck), a design tractive force equal to the holding capacity shall be assumed. When calculating the drum shaft the dynamic stopping forces of the brakes shall be considered. The drum brake is not to give way under this load. 3.7.4 Brakes If the drum brakes are power-operated, manual operation of the brake shall be provided additionally. Drum brakes shall be capable of being quickly released from the control stand on the bridge, as well as from any other control stand. The emergency release shall be functional under all working conditions, including failure of the power drive. The operating levers for the brakes shall be secured against unintentional operation. Following operation of the emergency release device, normal operation of the brakes shall be restored immediately. Following operation of the emergency release device, the winch driving motor are not to start again automatically. Towing winch brakes shall be capable of preventing the towline from paying out when the vessel is towing at the design force Tb and shall not be released automatically in case of power failure. 3.7.5 Tricing winches Control stands for the tricing winches shall be located at safe distance off the sweep area of the towing gear. Apart from the control stands on deck, at least one other control stand shall be available on the bridge. Tricing winches are not subject to classification. In order to assess the supporting structure, maximum reaction forces and its locations shall be provided. 3.7.6 Emergency release The winch shall be designed to allow drum release in an emergency, and in all operational modes. The release capabilities shall be as specified on towing arrangement drawing. The action to release the drum shall be possible locally at the winch and from a position at the bridge with full view and control of the operation. Identical means of equipment for the release operation to be used on all release stations.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 110

Part 5 Chapter 10 Section 11

3.7.2 Winch drum Specific requirements for winch drums:

Control handles, buttons etc. for emergency release shall be protected against unintentional operation.

3.8 Marking 3.8.1 Equipment shall be marked to enable them to be readily related to their specifications and manufacturer. When the Society's product certificate is required, the equipment shall be clearly marked by the Society for identification.

4 Fire safety and escape routes 4.1 Emergency exit from engine room 4.1.1 In the engine room an emergency exit shall be provided on or near the centerline of the vessel, which can be used at any inclination of the ship. The cover shall be weather tight and shall be capable of being opened easily from outside and inside. The axis of the cover shall run in athwart ship direction.

4.2 Companionways 4.2.1 Companionways to spaces below deck see [5.2.1].

4.3 Rudder compartment 4.3.1 Where, for larger ocean going tugs, an emergency exit is provided from the rudder compartment to the upper deck, the arrangement, sill height and further details shall be designed according to the requirements given in [5.2.3].

4.4 Access to bridge 4.4.1 Safe access to the bridge shall be ensured for all anticipated operating and heeling conditions, also in heavy weather during ocean towage.

4.5 Fire safety 4.5.1 Structural fire protection measures shall be as outlined in Pt.4 Ch.10, as applicable according to the size of the vessel. 4.5.2 Additional or deviating regulations of the competent administration shall be observed.

5 Stability and openings and closing appliances 5.1 General stability requirements 5.1.1 The requirements in this section apply to vessels with freeboard length LLL of 24 metres and above.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 111

Part 5 Chapter 10 Section 11

After an emergency release the winch brakes shall be in normal function without delay. It shall always be possible to carry out the emergency release sequence (emergency release and/or application of brake), even during a black-out.

5.1.3 The vessel's stability shall be assessed when the towing line is not in line with the vessel's longitudinal centre line. The towing heeling moment shall be calculated based on the assumption in [5.1.4]. The criterion in [5.1.5] shall be complied with. Guidance note: It is acceptable that compliance is demonstrated for actual loading conditions only. The approval will then be limited to the presented loading conditions. These initial conditions shall also comply with the relevant intact and damage stability criteria before applying the heeling moment. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

5.1.4 Towing heeling moment A transverse heeling moment generated by the rudder and propulsion system with maximum thrust and rudder(s) hard over is assumed to act horizontally on the towline as a static transverse force derived from the maximum bollard pull. No vertical force is assumed. A heeling lever curve as a function of the heeling angle shall be calculated as

where:

Fthr Tb

= taken as TbCT in kN

CT

= a transverse thrust and rudder force reduction factor depending on the propulsion arrangement:

= the maximum continuous bollard pull, in kN as defined in [3.3.3], measured in accordance with [1.5] C T shall be taken as not less than 0.6 for conventional single or twin propeller propulsion systems with rudders and fixed or no propeller nozzles. This value is increased to 0.7 for ships fitted with moveable nozzles. For single azimuth thrusters (Z-drives) acting normal to the centreline and for cycloidal drives a value of 1.0 shall be applied. For two azimuth thrusters CT is taken as (1 + cos γ) / 2, where γ is the offset angle that occurs between the thruster jets when one unit is directed at a right angle to the ship’s centreline and the other is directed so that its thrust jet tangentially intersects the nozzle of the first. Other values for CT may be accepted if substantiated by calculations

h

= the towing heeling arm, in m, taken as the vertical distance between the centre of propeller(s) and the fastening point of the towline

Δ

= is the displacement of the loading condition in t. The displacement, LCG and VCG for the initial loading condition is assumed to remain unchanged. If the vessel is intended to operate with additional transverse thrusters the heeling lever generated by the propulsion system shall be increased in proportion to the heeling moment generated by such thrusters.

5.1.5 Stability criterion for tugs The residual area between the righting lever curve and the heeling lever curve calculated in accordance with [5.1.4] shall not be less than 0.09 metre-radians. The area is determined from the first interception of the two curves to the angle of the second interception or the angle of down flooding, whichever is less.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 112

Part 5 Chapter 10 Section 11

5.1.2 Vessels with a freeboard length LLL less than 24 meters should as far as practicable comply with the requirements given in this section. Other stability requirements may however be applied provided the Society upon consideration in each case finds these requirements to be appropriate for the vessel.

5.1.6 Stability criteria for ocean towing For ships intended only for towing operations where the towline is secured against transverse movement near the aft perpendicular the following criteria may be applied in lieu of [5.1.3]: The residual area between the righting lever curve and the heeling lever curve calculated in accordance with [5.1.4] shall not be less than 0.055 metre-radians. The area is determined from the first interception of the two curves to the angle of the second interception or the angle of down flooding, whichever is less. The static angle at the first interception shall not be more than 15°. 5.1.7 Additional information The vessel’s stability manual shall contain additional information in on the maximum bollard pull, the assumed location of the fastening point of the towline, heeling force and moment and identification of critical flooding points. The heeling lever curve shall be plotted on the GZ curve for all intended towing conditions.

5.2 Openings and closing appliances 5.2.1 In general, openings and closing appliances shall be in compliance with the requirements of Pt.3 Ch.12 except as otherwise specified in this subsection. 5.2.2 Side scuttles and windows Side scuttles in the ship's sides and in sides of superstructures on freeboard deck shall at least satisfy the requirements for type B side scuttles as per ISO 1751. For windows in a wheelhouse in the second tier, Type E windows as per ISO 3903 are required when direct access to spaces below is provided. Glass thicknesses for intermediate sizes, not covered by ISO 3903, shall be determined using ISO 21005. 5.2.3 Weather deck openings Skylights in freeboard deck shall be arranged with coamings not less than 900mm high and scantlings shall be as for exposed casings. Skylights leading to machinery spaces shall be of steel and not contain glass panels. 5.2.4 Tugs with L<24m and tugs in domestic trade Ventilators necessary to continuously supply the machinery space shall be positioned as close to the centreline as possible, and have coamings exceeding 1.8m at the centreline of the vessel, linearly increased to 4.5m at the ship's side above the lower part of the weather deck, under which condition the opening needs not be fitted with a weathertight closing appliance.

6 Additional requirements for escort tugs 6.1 General 6.1.1 The escort rating number (Fs, t, v) should be established by full scale measurement tests. Alternatively, numerical calculations by suitable software, possible in combination with model tests, may be accepted. Requirements to the full scale testing and numerical calculations are outlined in [6.8]. 6.1.2 Escort rating numbers based on full scale test will have a qualifier F, while escort rating numbers based on calculations confirmed by the Society will have a qualifier N. Escort rating numbers established by other class societies (e.g. due to class entry of the vessel) will have a qualifier O.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 113

Part 5 Chapter 10 Section 11

Alternatively, the area under the righting lever curve shall not be less than 1.4 times the area under the heeling lever curve calculated in accordance with [5.1.4]. The areas are determined between 0° and the angle of the second interception or the angle of down flooding, whichever is less.

6.1.4 Full scale measurement test may be commenced either before delivery or anytime during the operational life of the vessel. The class notation and the appendix to the class certificate will then be updated to reflect the results of the test.

6.2 Hull arrangement 6.2.1 The hull of the tug shall be designed to provide adequate hydrodynamic lift and drag forces when in indirect towing mode. Due attention shall be paid to the balance between hydrodynamic forces, towline pull and propulsion forces, as well as sudden loss of thrust. 6.2.2 The vessel shall be designed so that forces are in equilibrium with a minimum use of propulsive force except for providing forward thrust and balancing transverse forces during escorting service. 6.2.3 The escort rating number (FS, t, v) shall be determined by numerical calculations or full scale trials, performed within acceptable limits set by stability and winch criteria specified in these rules, and further described in DNVGL-CG-0155. A test certificate indicating the escort rating number may be issued on completion of successful full scale trials. If trials take place at both 8 and 10 knots, the escort rating number will consist of 6 parts. 6.2.4 FS indicates maximum transverse steering pull, in ton, exerted by the escort tug on the stern of the assisted vessel with the intention of controlling it, t is the time required for the change of the tug's position from one side to the corresponding opposite side, and v is the speed at which this pull may be attained (see Figure 1).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 114

Part 5 Chapter 10 Section 11

6.1.3 Escort rating number (Fs, t, v) is defined in [6.2.4]. If one or more of these parameters are not established (e.g. "t"), the value will be replaced by "-".

Part 5 Chapter 10 Section 11 Figure 1 Typical escort configuration

6.3 Equipment 6.3.1 Towing winch The towing winch shall have a hydraulic load reducing system in order to prevent overload caused by dynamic oscillation in the towing line. Normal escort operation shall not be based on use of brakes on the towing winch, but the hold function shall be provided by the gearbox and the hydraulic system instead. The towing winch shall pay out towing line before the pull reaches 110% of the rated towline force FW in t. 6.3.2 The winch, crucifix etc. and their supporting structures for vessels with notation Escort tug shall also comply with the requirements for Tug notation based on towline force FW, see Figure 1, instead of design force Tb as given in Table 3.

6.4 Propulsion system 6.4.1 The propulsion system shall be able to provide ample thrust for manoeuvring at higher speeds for the tug being in any oblique angular position and to catch up with the assisted vessel. The design speed of the escort tug shall therefore be at least 20% higher than the escort speed v defined in [6.1.4].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 115

6.4.3 In case of loss of propulsion, the remaining forces shall be so balanced that the resulting turning moment will turn the escort tug to a safer position with reduced heel.

6.5 General stability requirements 6.5.1 The general stability criteria in [5.1] shall be complied with, in addition to stability criteria given below.

6.6 Additional stability criteria 6.6.1 The area under the righting arm curve and heeling arm curve shall satisfy the following ratio:

RABS ≥ 1.25 RABS = ratio between righting and heeling areas between equilibrium and 20° heeling angle. Equilibrium is obtained when maximum steering force is applied from tug.

6.6.2 Heeling arm shall be derived from the test or calculations. The heeling arm shall be kept constant from equilibrium to 20°, see Figure 2.

Figure 2 Equilibrium to 20° Guidance note: The heeling arm shall be taken as escort heeling moment divided by the displacement. For preliminary calculations the heeling arm may be taken as the maximum value that ensures compliance with the criteria given in [6.6.1] and [6.6.3]. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

6.6.3 The following requirement shall be satisfied: A + B ≥ 1.4(B + C)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 116

Part 5 Chapter 10 Section 11

6.4.2 The propulsion system shall also have sufficient thrust so that the tug can maneuver safely aft of the escorted vessel when transferring the tow line etc.

A+B = area under the GZ curve B+C = area under the heeling moment curve. The areas are taken from 0° heel to the angle of down flooding or 40°, whichever is less. See Figure 3.

Figure 3 Total area requirements

6.7 Load line 6.7.1 Freeboard Freeboard shall be arranged so as to avoid excessive trim at higher heeling angles. Bulwark shall be fitted all around exposed weather deck.

6.8 Methods for establishing the escort rating number (Fs, t, v) 6.8.1 Requirements to full scale measurement tests are given in [6.9] and in DNVGL-CG-0155, while requirements to numerical calculations are described in [6.10] and in DNVGL-CG-0155. These tests are additional to the tests given in [1.5]. 6.8.2 The presented steering pull Fs is intended to represent the force the escort tug can exert under normal sea trial conditions. If the vessel is intended to operate in higher sea conditions the expected pull may be lower.

6.9 Full scale testing requirements for notation Escort tug (F, (FS, t, v)) 6.9.1 The following tests shall be undertaken: — Measurement of maximum transverse steering pull Fs, in ton: The escort tug will connect its towing line wire to the assisted vessel's stern and follow it with the wire slack, both ships travelling at the same speed. The tug will then position itself at an agreed angle of attack relative to the flow of water and the resulting towline tension Fs shall be recorded. These readings combined with the respective θ-β angles combinations shall be then used to establish Fs.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 117

Part 5 Chapter 10 Section 11

where:

The escort test speed should be 8 knots and/or 10 knots. A surveyor will attend the test for the purpose of witnessing compliance with the agreed test program. 6.9.2 Approved escort departure and escort arrival loading conditions from the stability manual shall define the way the tug will be loaded for the trial. 6.9.3 Recordings during full scale trials At least the following data shall be recorded continuously in real time mode during trials for later analysis. Assisted vessel: — — — — — — —

speed relative to the sea time for the manoeuvre test weather condition (speed and direction) and sea state position heading rudder angle towline angle θ.

Active escort tug: — — — — — — —

towline tension Fw towline length oblique angle β heeling angle of tug weather condition (speed and direction) and sea state. heading speed relative to the sea.

6.9.4 Sea trials exceeding critical heeling angle from approved stability calculations shall not be accepted.

6.10 Numerical calculations for notation Escort tug (N, (FS, t, v)) 6.10.1 The calculations shall be based on hydrodynamic loads established by model tests or CFD calculations relevant for the actual vessel design. 6.10.2 The calculations shall be done by suitable software/calculation method for which the results have been aligned with results from full scale measurement tests. 6.10.3 The documentation shall contain information about the actual propulsion system and the available thrust in the given directions.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 118

Part 5 Chapter 10 Section 11

— Manoeuvre test: The escort tug will shift its position from a steering position minimum 30° from one side of the assisted vessel (i.e. θ is max 60°) to the mirror position in the opposite side and t will be the time required.

Symbols For symbols not defined in this chapter, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended for dredging operations in harbour and open waters.

1.2 Scope 1.2.1 The following subjects are covered in this section: — hull structural details related to the dredging operations — supporting structures for the dredging equipment. Guidance note: The Society may on request supervise the construction and testing of the following items nor covered by the classification: —

equipment for anchoring and mooring during dredging

—

equipment and installations for dredging. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section may be given the class notation Dredger, or Dredger(Suction). Requirements for split hopper barges used in dredging operations are found in Ch.11. The requirements of the Guidelines for the Assignment of Reduced Freeboards for Dredgers (DR-68) developed by the joint working group on dredgers operating at reduced freeboards apply. 1.3.2 Dredgers intended for unusual dredging methods and/or of unusual form will be specially considered. 1.3.3 Dredgers engaged in international service shall comply with the requirements of the ICLL. 1.3.4 Dredgers with a restricted service area operating exclusively in national waters shall comply, as far as possible, with the requirements of the ICLL. The height of companionway coamings above deck shall not be less than 300 mm. Guidance note: For dredgers with a restricted service area according to Pt.1 Ch.2 Sec.5 operating exclusively in national waters, a special dredger freeboard is assigned by some administrations. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 119

Part 5 Chapter 10 Section 12

SECTION 12 DREDGERS

2.1 General requirements 2.1.1 Local structures and deviations from the principal design dimensions associated with the attachment of the dredging gear, shall be ignored when determining the principal dimensions in accordance with Pt.3 Ch.1 Sec.4 [3.1]. 2.1.2 The thickness of main structural members which are particularly exposed to abrasion by a mixture of spoil and water, e.g. where special loading and discharge methods are employed, shall be adequately strengthened. Upon approval by the Society such members may alternatively be constructed of special abrasion resistant materials.

2.2 Hull girder strength 2.2.1 For dredgers of 100 m in length and more, the scantlings of the longitudinal hull structure shall be determined on the basis of longitudinal bending moments and shear forces calculations according to Pt.3 Ch.5 Sec.1. For dredgers classed for particular service areas, dispensations of Pt.3 Ch.5 Sec.1 may be approved. 2.2.2 For dredgers of less than 100 m in length, the minimum midship section modulus according to Pt.3 Ch.5 Sec.1 [2.2] shall be fulfilled. For dredgers less than 100 m in length, the submittal of longitudinal strength calculations may in some cases be waived upon request.

2.3 Hull local scantlings 2.3.1 The thickness of the bottom shell plating of dredgers intended or expected to operate while aground, shall be increased by 20% above the value required in Pt.3 Ch.6 Sec.3 and Sec.4. 2.3.2 Where hopper doors are fitted on the vessel's centreline or where there is a centreline well for dredging gear (bucket ladder, suction tube etc.), a plate strake shall be fitted on each side of the well or door opening. The width shall not be less than 50% of the rule width of the flat keel, and the thickness shall not be less than that of the rule flat keel. The same applies where the centreline box keel is located above the base line at such a distance that it cannot serve as a docking keel. In this case, the bottom plating of the box keel need not be thicker than the rule bottom shell plating. 2.3.3 The flat bottom plating of raked ends which deviate from common ship forms, shall have a thickness not less than that of the rule bottom shell plating within 0.4 L amidships, up to 500 mm above the maximum load waterline. The shell plating above that shall have a thickness not less than the rule side shell plating. The reinforcements required in [2.3.1] shall be observed. 2.3.4 The corners of hopper door openings and of dredging gear wells shall comply with Pt.3 Ch.3 Sec.5 [5]. The design of structural details and welded connections in this area shall be carried out with particular care.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 120

Part 5 Chapter 10 Section 12

2 Hull arrangement and strength

2.4.1 Abreast of hoppers and centreline dredging wells, the floors shall be dimensioned in accordance with Pt.3 Ch.6. The depth, in mm, of floor shall satisfy the following formula:

2.4.2 Floors, longitudinal girders etc. below dredging machinery and pump seats shall be adequately designed for the additional loads. 2.4.3 Where floors are additionally stressed by the reactions of the pressure required for closing the hopper doors, their section modulus and their depth shall be increased accordingly. 2.4.4 Where the unsupported span of floors exceeds 3 m, one side girder shall be fitted with web net 2 thickness, in mm, and flange sectional net area, in cm , shall satisfy:

Towards the ends, the web thickness and the sectional area of the flange may be reduced by 10%. 2.4.5 Floors in line with the hopper lower cross members fitted between hopper doors shall be connected with the hopper side wall by brackets of approx. equal legs. The brackets shall be flanged or fitted with face bars and shall extend to the upper edge of the cross members. 2.4.6 Floors of dredgers intended or expected to operate while aground shall be stiffened by vertical buckling stiffeners the spacing of which is such as to guarantee that the reference degree of slenderness λ for the plate field is less than 1.0. For

λ see the Society's document DNVGL-CG-0128 Sec.3 [2.2.2].

2.5 Single bottom - longitudinally stiffened 2.5.1 The spacing of primary supporting bottom transverses is generally not to exceed 3.6 m. The gross 3 2 offered section modulus, in cm , and gross offered web cross sectional area, in cm , shall not be less than determined by the following formulas:

where:

e = spacing, in m, of bottom transverses between each other or from bulkheads. ℓ = unsupported span, in m, any longitudinal girders not considered. P = design pressure for the considered design load set, see Pt.3 Ch.6 Sec.2 [2], calculated at the load 2

calculation point defined in Pt.3 Ch.3 Sec.7 [2.2], in kN/m .

The web depth shall not be less than the depth of floors according to [2.4.1]. 2.5.2 The bottom longitudinals shall be determined in accordance with Pt.3 Ch.6 Sec.5 [1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 121

Part 5 Chapter 10 Section 12

2.4 Single bottom - transversely stiffened

The thickness of the brackets shall at least to be equal to the web thickness of the adjacent bottom transverses. The brackets shall be flanged or fitted with face bars. 2.5.4 Where longitudinal bulkheads and the side shell are framed transversely, the brackets according to [2.5.3] shall be fitted at every frame and shall extend to the bilge. 2.5.5 The bottom transverses shall be stiffened by means of flat bar stiffeners at every longitudinal. 2.5.6 The bottom structure of dredgers intended or expected to operate while aground shall be dimensioned as follows: — the spacing of the bottom transverses according to [2.5.1] is not to exceed 1.8 m. The webs shall be stiffened according to [2.4.6] — the section modulus of the bottom longitudinals according to [2.5.2] shall be increased by 50%. 2.5.7 The requirements of [2.4.2] to [2.4.5] shall be applied analogously.

2.6 Double bottom 2.6.1 Double bottoms need not be fitted adjacent to the hopper spaces. 2.6.2 In addition to the requirements given in Pt.3 Ch.3 Sec.5 [6] and Pt.3 Ch.6, plate floors shall be fitted in way of hopper spaces intended to be unloaded by means of grabs. 2.6.3 Where brackets are fitted in accordance with [2.6.6], the requirements according to [2.5.3] and [2.5.4] shall be observed where applicable. 2.6.4 The bottom structure of dredgers intended or expected to operate while aground shall be strengthened as follows: — Where transverse framing system is adopted, plate floors shall be fitted at every frame and the spacing of the side girders shall be reduced to half the spacing of what is required in [2.6.5]. — When the longitudinal framing system is adopted, and the longitudinal girders are fitted instead of longitudinals, the spacing of floors may be greater than five (5) times the mean longitudinal frame spacing, proven that adequate strength of the structure is proved. The required net plate thickness, t in mm, of the longitudinal girders shall not be less than obtained from the following formula:

Where applicable, [2.5.6] shall be applied analogously. The net thickness of bottom plating shall be increased by 10%, compared to the plate thickness requirement given in Pt.3 Ch.6. 2.6.5 Bottom side girder arrangement The distance of the side girders from each other and from centre girder and ship's side respectively shall not be greater than: — — — —

1.8 4.5 4.0 3.5

m m m m

in the engine room within the engine seatings where one side girder is fitted in the other parts of double bottom where two side girders are fitted in the other parts of double bottom where three side girders are fitted in the other parts of double bottom.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 122

Part 5 Chapter 10 Section 12

2.5.3 Where the centerline box keel cannot serve as a docking keel, brackets shall be fitted on either side of the centre girder or at the longitudinal bulkheads of dredging wells and of hopper spaces. The brackets shall extend to the adjacent longitudinals and longitudinal stiffeners. Where the spacing of bottom transverses is less than 2.5 m, one bracket shall be fitted. For larger spacings, two brackets shall be fitted.

One bracket shall be fitted at each side of the centre girder between the plate floors where the plate floors are spaced not more than 2.5 m apart. Where the floor is greater, two brackets shall be fitted.

2.7 Hopper and well construction 2.7.1 Plating The net plate thickness, in mm, shall not be less than determined by the following formula:

where:

b tmin

= breadth of plate panel, in mm, as defined in Pt.3 Ch.3 Sec.7 [2.1.1]

P

= design pressure on hopper and well constructions for the considered design load set, see Pt.3 Ch.6 2 Sec.2 [2], calculated at the load calculation point defined in Pt.3 Ch.3 Sec.7 [2.2], in kN/m .

= minimum plate thickness, in mm, as defined in Pt.3 Ch.6 Sec.3 [1], Pt.3 Ch.6 Sec.3 [2] and Pt.3 Ch.6 Sec.3 [3]

2.7.2 Stiffeners 3 The net section modulus, in cm , of stiffeners shall not be less than required in Pt.3 Ch.6 Sec.5. 2.7.3 The strength shall not be less than that of the ship's sides. Particular attention shall be paid to adequate scarfing at the ends of longitudinal bulkheads of hopper spaces and wells. The top and bottom strakes of the longitudinal bulkheads shall be extended through the end bulkheads, or else scarfing brackets shall be fitted in line with the walls in conjunction with strengthening at deck and bottom. Where the length of wells does not exceed 0.1 L and where the wells and/or ends of hopper spaces are located beyond 0.6 L amidships, special scarfing is, in general, not required. 2.7.4 In hoppers fitted with hopper doors, transverse girders shall be fitted between the doors the spacing of which is normally not to exceed 3.6 m. 2.7.5 Primary supporting members The depth of the transverse girders spaced in accordance with [2.7.4] shall not be less than 2.5 times the depth of floors as defined in [2.7.6]. The web plate thickness shall not be less than the thickness of the side shell plating. The top and bottom edges of the transverse girders shall be fitted with face plates. The thickness of the face plates shall be at least 50% greater than the rules web thickness. Where the transverse girders are constructed as watertight box girders, the scantlings shall not be less than required according to [2.7.1] to [2.7.4]. At the upper edge, a plate strengthened by at least 50% shall be fitted. 2.7.6 The depth, in mm, of floors plates is defined as:

2.7.7 Vertical stiffeners spaced not more than 900 mm apart shall be fitted at the transverse girders. 2.7.8 The transverse bulkheads at the ends of the hoppers shall extend from board to board.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 123

Part 5 Chapter 10 Section 12

2.6.6 Brackets Where the ship's sides are framed transversely flanged brackets having same thickness as of the floors shall be fitted between the plate floors at every transverse frame, extending to the outer longitudinals at the bottom and inner bottom.

The density of the spoil shall be considered when determining the scantlings. 2.7.10 Strong beams shall be fitted transversely at deck level in line with the web frames according to [2.7.9]. The scantlings shall be determined, for the actual loads complying with an equivalent stress, in N/ 2 mm , of:

The maximum reactions of hydraulically operated rams for hopper door operation are, for instance, to be taken as actual load. The strong beams shall be supported by means of pillars according to Pt.3 Ch.6 Sec.6 [3] at the box keel, if fitted. 2.7.11 On bucket dredgers, the ladder wells shall be isolated by transverse and longitudinal cofferdams at the bottom, of such size as to prevent the adjacent compartments from being flooded in case of any damage to the shell by dredging equipment and dredged objects. The cofferdams shall be accessible.

2.8 Box keel 2.8.1 Bottom plating — Where the box keel can serve as a docking keel, the requirements for flat plate keels according to Pt.3 Ch.6 Sec.3 [1.1] and Pt.3 Ch.3 Sec.5 [6] apply. — Where the box keel cannot serve as a docking keel (see also [2.3.2]), the requirements for bottom plating according to Pt.3 Ch.6 Sec.3 [1.1] and Pt.3 Ch.6 Sec.4 [1] apply. 2.8.2 Plating other than bottom plating — Outside the hopper space, the requirements for bottom plating according to Pt.3 Ch.6 Sec.3 [1.1] and Pt.3 Ch.6 Sec.4 [1] apply. — Within the hopper space the requirements for hopper space plating according to [2.7.1] apply. The thickness of the upper portion particularly subjected to damage shall be increased by not less than 50%. 2.8.3 Floors The requirements according to [2.4.1] and [2.4.2] respectively apply. 2.8.4 Stiffeners The requirements for hopper stiffeners according to [2.7.2] apply. 2.8.5 Primary supporting members Strong webs of plate floors shall be fitted within the box keel in line with the web frames according to [2.7.9] to ensure continuity of strength across the vessel. 2.8.6 With regard to adequate scarphing at the ends of a box keel, [2.7.3] shall be observed.

3 Systems and equipment 3.1 Stern frame 3.1.1 Where dredgers with stern wells for bucket ladders and suction tubes are fitted with two rudders, the stern frame scantlings shall be determined in accordance with Pt.3 Ch.10 Sec.6 [2].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 124

Part 5 Chapter 10 Section 12

2.7.9 Regardless of whether the longitudinal or the transverse framing system is adopted, web frames in accordance with Pt.3 Ch.6 Sec.6 shall be fitted in line with the transverse girders according to [2.7.4].

3.2.1 Where dredgers are fitted with auxiliary propulsion and their speed does not exceed 5 kn at maximum draught, the value V0 = 7 kn shall be taken for determining the rudder stock diameter.

3.3 Anchoring and mooring equipment 3.3.1 The equipment of anchors, chain cables, wires and recommended ropes for dredgers for unrestricted service area having normal ship shape of the underwater part of the hull shall be determined in accordance with Pt.3 Ch.11 Sec.1. When calculating the equipment number according to Pt.3 Ch.11 Sec.1 [3], bucket ladders and gallows need not to be included. For dredgers of unusual design of the underwater part of the hull, the determination of the equipment requires special consideration. The equipment for dredgers for restricted service area shall be determined according to the service notations given in Pt.3 Ch.11 Sec.1 [3.2]. 3.3.2 The equipment of non self-propelled dredgers shall be determined as for barges, in accordance with Ch.11 Sec.3. 3.3.3 Considering rapid wear and tear, it is recommended to strengthen the anchor chain cables which are also employed for positioning of the vessel during dredging operations. 3.3.4 Dredgers intended to work in conjunction with other vessels shall be fitted with strong fenders.

4 Fire safety 4.1 Closed hopper spaces 4.1.1 On dredgers with closed hopper spaces suitable structural measures shall be taken in order to prevent accumulation of inflammable gas-air mixture in the hopper vapour space. The requirements given in Pt.4 Ch.8 Electrical installations, shall be observed.

5 Openings and closing appliances 5.1 General requirements 5.1.1 Where a dredger freeboard is assigned in accordance with [1.3.3], the length LLL, draught TLL and block coefficient CB-LL according to Pt.3 Ch.1 Sec.4 [3.1] shall be determined for this freeboard.

5.2 Bulwark, overflow arrangements 5.2.1 Bulwarks shall not be fitted in way of hoppers where the hopper weirs discharge onto the deck instead of into enclosed overflow trunks. Even where overflow trunks are provided, it is recommended not to fit bulwarks. If bulwarks are fitted, freeing ports shall be provided throughout their length. They shall be of sufficient width to permit undisturbed overboard discharge of any spoil spilling out of the hopper in the event of rolling.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 125

Part 5 Chapter 10 Section 12

3.2 Rudder stock

The construction shall be such as not to require cut-outs at the upper edge of the sheer strake. Where overflow trunks are carried through the wing compartments, they shall be arranged such as to pierce the sheer strake at an adequate distance from the deck. 5.2.3 Dredgers with restricted service area notation may have overflow arrangements which permit discharge of excess water during dredging operations onto the deck.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 126

Part 5 Chapter 10 Section 12

5.2.2 Dredgers without restricted service range notation shall be fitted with overflow trunks on either side suitably arranged and of sufficient size to permit safe overboard discharge of excess water during dredging operations.

Symbols For symbols and definitions not defined in this chapter, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction These rules provide requirements for ships specially intended for pushing.

1.2 Scope The rules in this section give requirements for hull strength, and systems and equipment, applicable to a pusher.

1.3 Application 1.3.1 Vessels built in compliance with the relevant requirements in this section may be given the class notation Pusher. 1.3.2 A pusher vessel intended for operation in combination with a number of barges/pontoons specially designed to accommodate the pusher will be subject to special consideration. Additional requirements to the barge/pontoon is given in Ch.11. 1.3.3 For a pusher/barge or a pusher/pontoon combination the identification numbers of the barges/ pontoons associated with the pusher will be given in the appendix to classification certificate.

2 Definitions 2.1 Terms Table 1 Definitions of terms Term

Definition

type I pusher barge/ pontoon unit

The connection between the pusher and the barge/pontoon is assumed to be rigid, i.e. it should be designed to transmit the static and dynamic shearing forces and bending moments in such a manner that the combination behaves like one integrated structure

type II pusher barge/ pontoon unit

The connection between the pusher is free to heave and/or pitch relatively to the barge/ pontoon. This type of connection will normally not be applicable under severe sea conditions or in iceinfested waters.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 127

Part 5 Chapter 10 Section 13

SECTION 13 PUSHERS

3.1 Subdivision arrangement 3.1.1 Watertight bulkhead arrangement The pusher shall have a number of transverse bulkheads corresponding to its own length, as given in Pt.3 Ch.2 Sec.2 [4].

4 Hull 4.1 General 4.1.1 The pusher shall be regarded as a separate unit and the hull structural strength is in general to be as required for the main class. 4.1.2 When the pusher is connected as an integrated part of a combined system (pusher/barge unit or pusher/pontoon unit), the hull scantlings of exposed parts of the pusher shall satisfy the main class rules for aft structures as calculated for the combined unit. 4.1.3 Pushers being part of a flexible system, type II, shall be equipped also for towing the barge/pontoon.

4.2 Draught for scantlings For determining the scantlings of strength members based on the vessel's draught, the latter shall not be taken less than 0.85 D.

4.3 Structure in the forebody 4.3.1 The structure in the forebody shall be satisfactorily reinforced to sustain the reaction forces occurring during the pushing operation. For complex structures stress analysis shall be carried out to show that the stress level will be within acceptable limits. 4.3.2 In combined pusher/barge or pusher/pontoon systems the connection forces and allowable stresses shall comply with the requirements given in Ch.11 Sec.2 [10.4]. 4.3.3 In combined pusher/barge or pusher/pontoon systems the deflections of the structure during operation shall be limited to avoid hammering when pusher/barge or pusher/pontoon units are heeled.

5 Equipment 5.1 Rudder The design rudder force on which scantlings shall be based, shall be calculated as indicated for the main class. The speed of the vessel is however not to be taken less than V = 10 knots.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 128

Part 5 Chapter 10 Section 13

3 Subdivision arrangement design

The steering gear shall be capable of bringing the rudder from 35 degrees on one side to 30 degrees on the other side in 20 seconds, when the vessel is running ahead at maximum service speed. For the combined pusher/barge unit, the requirement is 28 seconds.

5.3 Anchoring and mooring Pushers shall have anchoring and mooring equipment corresponding to its equipment number, see Pt.3 Ch.11 Sec.1 [3.1]. The term 2 BH in the formula may, however, be substituted by: 2(aB + Σ hibi) where:

bi = breadth, in m, of the widest superstructure or deckhouse of each tier having a breadth greater than B/4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 129

Part 5 Chapter 10 Section 13

5.2 Steering gear

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended to serve as floating facilities for reception and processing of oily water and oil residues.

1.2 Scope 1.2.1 These rules include requirements for hull strength, systems and equipment and procedures applicable to vessels serving as a floating facility for reception and processing of oily water and oil residues. 1.2.2 The classification of the facility will be based upon the following assumptions: — That oily water and oil residues originating from oil with flash point below 60°C are considered to maintain a flash point below 60°C and that such liquids are not transferred to the facility's engine room. — That transfer of oily water and oil residues between delivery vessel and the facility is only done under favorable weather conditions. — That the facility is operated by qualified personnel. — That a two-way communication system is provided between the delivery vessel and the facility during the transfer operation, ensuring reliable and direct contact with the personnel controlling the transfer pump. 1.2.3 The above basic assumptions will be stated in the appendix to the classification certificate.

1.3 Application 1.3.1 The rules in this chapter apply to newbuildings as well as to conversions of existing vessels to serve as floating facilities for reception and processing of oily water and oil residues. The subsequent requirements shall be regarded as supplementary to the requirements for main class and relevant requirements as given in Ch.5 for ships intended for carriage of oil with flashpoint below 60°C. 1.3.2 Facilities designed and built, surveyed and tested in compliance with the requirements in this section and other relevant requirements may be given the class notation Slop reception vessel. 1.3.3 The classification is aimed at safety against hazards to the personnel, the facility and the environment. 1.3.4 The assignment of class will be based upon: — — — — —

approval of documentation i.e specifications, plans, calculations, etc. approval of the instruction manuals for the facility inspection during manufacturing of materials and equipment inspection during construction, installation and testing of the facility inspection upon completion, including testing of the separating system for proper function. Guidance note: In addition to the requirements of the Society, relevant requirements in the regulations of national authorities will have to be complied with in connection with the registration and or location of the facility. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 130

Part 5 Chapter 10 Section 14

SECTION 14 SLOP RECEPTION VESSEL

— — — — —

drawings and specification for the separating system drawing of the fendering arrangement specification of transfer hoses drawings of deck lightning arrangement instruction manuals for the facility.

1.3.6 The following control and monitoring systems shall be approved by the Society: — — — —

oil separating system fire extinguishing system fire detection system inert gas system.

For requirements to documentation, see Pt.4 Ch.9. 1.3.7 The following control and monitoring system shall be certified according to Pt.4 Ch.9: — oil separating system — fire detection system — inert gas system.

2 Hull strength and arrangement 2.1 General requirements 2.1.1 In addition to the hull strength requirements of the rules for main class, the following shall be given special consideration: — Additional openings in strength members. The local strength shall be considered in connection with openings and cut-outs in deck, bulkheads, etc. — Loading conditions. The longitudinal strength shall be satisfactory for all relevant loading conditions and conditions during transfer to new location. In addition to a loading manual, the facility shall be equipped with a loading instrument. — Tank pressure. The local strength shall be considered for increased internal pressure in the tanks caused by the separating process. 2.1.2 An efficient fender arrangement, effectively supported by hull strength members, shall be fitted. The fenders shall be able to keep the hulls of the delivery vessel and the reception facility apart at a safe distance, at least 3 meters. The fenders shall efficiently prevent steel to steel contact, in order to avoid risk for sparks. 2.1.3 The vessel shall comply with all requirements of MARPOL Annex I as applicable for an oil tanker, unless alternative acceptance is obtained from the flag and port state(s) in the area in which the vessel is going to operate. The requirements to double hull and segregated ballast are however considered to be minimum requirements. It is recognized that for vessels primarily operating within port limits or MARPOL Annex I special areas, certain requirements, such as those to oil discharge monitoring systems may not be applicable, provided all tank washings and oily mixtures are discharged to shore or alternative means for preventing discharge of oil to sea are provided.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 131

Part 5 Chapter 10 Section 14

1.3.5 In addition to the relevant parts of the documentation as required for oil tankers in Ch.5 Sec.1 [4.2], the following shall be submitted for approval:

2.2.1 The minimum bursting pressure for the hose assembly shall be 20 bar. The maximum allowable working pressure shall be at least 8 bar. 2.2.2 Hose diameters shall be sufficient for the maximum specified transfer rate for the facility in order to avoid excessive pressure drop. Hoses shall be suspended by suitable equipment. Excessive bending of the hoses shall be avoided. 2.2.3 A pressure gauge shall be fitted in the transfer line, before the reception tanks. 2.2.4 It shall be possible to drain or close mechanical loading arms or hoses before disconnection. Coamings of suitable height shall be arranged below manifolds and hose connections in order to minimize spill.

2.3 Lightning 2.3.1 Deck lighting shall be arranged. Adequate illumination shall be provided: — for the transfer area to facilitate control and handling of the equipment — for the fire extinguishing equipment — for visual observation of possible oil in the processed water being discharged to the sea (see [2.4.4]).

2.4 Separating system 2.4.1 The separating system shall be designed to reduce the oil content in the water being discharged into the sea to a concentration not exceeding 15 parts per million or any other lower value specified by the builder/owner. The actual design performance will be stated in the appendix to the classification certificate for the facility. 2.4.2 Precautions shall be taken to avoid overpressuring of the process tanks. When the separating system is arranged for pumping oil/water into a tank or series of tanks which by the design of the process piping arrangement will operate in the full condition, an overflow pipe with sectional area at least 25% greater than the area of the filling pipe shall be arranged from the first tank to another tank with surplus capacity. 2.4.3 Means for locating the oil/water interface in the tanks shall be provided. 2.4.4 Visual control of oil content in the processed water being discharged into the sea shall be possible by observing the sea surface at the outlet. Visual inspection of the surface in the last separating tank may alternatively be accepted. 2.4.5 Discharges of processed water from the separating process shall take place above waterline. 2.4.6 The maximum flow rate through the separating tanks shall be specified in the instruction manuals for the types of oil in question (different gravities, etc.). 2.4.7 Arrangements for handling and storage of sediments and separated oil residues shall comply with applicable requirements for cargo systems on oil tankers as given in Ch.5 of the rules.

2.5 Oil content monitoring 2.5.1 Automatic monitoring of oil content in the processed water shall be arranged. When the specified limit is exceeded, automatic stop of the discharge and an alarm shall be activated.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 132

Part 5 Chapter 10 Section 14

2.2 Transfer arrangement for transfer of oily water and oil residues

2.5.3 The oil content monitor shall be located outside gas dangerous spaces or zones unless the monitor is certified safe.

2.6 Protection against fire and explosion 2.6.1 Precautions shall be taken to prevent hydrocarbon gas from the delivery vessel to enter gas-safe spaces or zones on the facility and vice versa. The location and the periodical closing of doors and air intakes for ventilating systems, etc., shall be considered as well as the provision of air locks. 2.6.2 Means for preventing sparks from the funnel of the facility to reach gas dangerous spaces or zones (i.e. spark arrester) shall be provided. 2.6.3 The fire protection, extinguishing and detection arrangements shall in general comply with the relevant requirements of Ch.5 for oil tankers. 2.6.4 A fixed deck foam system in accordance with SOLAS Ch. II-2 Reg.10.8 and FSS Code Ch.14 shall be installed. 2.6.5 An inert gas system complying with the rules for the class notation Inert shall be arranged for supplying inert gas to all tanks which may contain hydrocarbon gases under normal operating conditions. 2.6.6 The capacity of the inert gas plan shall be at least 25% greater than the maximum discharge rate for processed water. 2.6.7 Electrical installations shall comply with applicable requirements in Ch.5. 2.6.8 Oil residues with flash point above 60°C originating from engine rooms may be transferred to tanks within the facility’s engine room, and may be burnt or incinerated within the engine room.

3 Operational instructions and log book 3.1 Instruction materials 3.1.1 Instruction manuals for the facility shall be prepared and kept onboard. The manuals are subject to approval by the Society. The manuals shall contain necessary information on: — — — — —

operation maintenance testing identification of faults repair.

For the following equipment and systems: — — — — — —

fire detection and extinguishing equipment inert gas system O2-content analyzer oily water and oil residues transfer arrangement oil content monitoring system other equipment onboard necessary for a safe and pollution-free operation

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 133

Part 5 Chapter 10 Section 14

2.5.2 The oil content meter shall be type tested in accordance with relevant IMO specifications and guidelines (Res. MEPC.107(49) or revised version of the same).

3.1.2 The instruction manuals shall also contain relevant information about the operational procedures to be applied onboard, such as: — mooring — safety actions (required closing of doors and ventilating intakes, etc.) to be carried out before commencing the transfer between the delivery vessel and the facility — general procedures for operation of the separating system and the inert gas system. 3.1.3 The operational procedures shall include the following: — The O2-content of storage and separating tanks which are not completely filled, shall be checked upon discharge, and in any case at least twice a week. — Two-way communication between the reception facility and the delivery vessel shall be established before the transfer commences. — Before discharge into the sea is begun, visual inspection of the surface (see [2.4.4]) shall be carried out and the automatic oil content monitor checked and started. 3.1.4 The maintenance procedures shall include: — Intervals for checking and maintenance of the exhaust spark arrestors.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 134

Part 5 Chapter 10 Section 14

— the complete separating system, including possible limitations (pumping rates, types of oil, etc.).

Guidance note: For the purpose of record keeping and for documentation versus local/national authorities it is recommended that the following guidelines are complied with: 1)

General. The facility should be provided with a safety and oily water/oil residues log book. The officer in charge of the operations concerned should be responsible for the entries in the log book. The log book should be kept onboard available for inspection. The log book entries should be kept onboard for a period of at least three years.

2)

Entries in the log book. The log book should be arranged for entries of the following which should be recorded without delay: —

before the transfer operations are commenced: —

what will be transferred

—

stipulated pumping rate

—

total volume to be transferred

—

safety actions carried out

—

rate of transfer

—

total volume to be transferred

—

weather conditions during transfer

—

volume and the exact time when processed water is discharged into the sea

—

exact time when the oil content in the processed water being discharged into the sea exceeds the specified limit

—

internal transfer of oily water and oil residues

—

use of the inert gas plant

—

result and the exact time of checking O2-content in the tanks

—

inspection and testing of fire detection and extinguishing equipment

—

inspection and maintenance of the inert gas plant

—

inspection and maintenance of the exhaust spark arrester

—

inspection and maintenance of the transfer arrangement

—

inspection and maintenance of the oil content monitor. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 135

Part 5 Chapter 10 Section 14

3.2 Safety and oily water/oil residues log book

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended to carry refrigerated cargoes.

1.2 Scope 1.2.1 These rules include the class notations and references to the requirements for refrigerated cargo vessels.

1.3 Application 1.3.1 The rules, as relevant, in this chapter apply to ships with refrigerating plants for: — carriage of refrigerated dry cargo — carriage of fruit or vegetables under a controlled atmosphere — carriage in bulk of refrigerated fruit juices and similar liquid cargoes when a class notation in [1.4] is requested.

1.4 Class notations 1.4.1 Ships designed, built, equipped and tested under the supervision of the Society in compliance with the requirements of this chapter and the requirements to class notation RM(X°C/Y°C sea) in Pt.6 Ch.4 Sec.10 may be given one of the additional class notations in [1.4.2] and [1.4.3]. 1.4.2 Ships primarily constructed for the for carriage of refrigerated dry cargo may be given the class notation Reefer RM(X°C/Y°C sea). 1.4.3 Ships primarily constructed for the carriage of fruit juices and similar cargoes in bulk in refrigerated tanks shall be given the class notation Refrigerated fruit juice carrier RM(X°C/Y°C sea) provided they also comply with relevant parts of the rules in Ch.6 (e.g. for cargo handling systems and independent cargo tanks). Guidance note: For dry cargo ships having a partial cargo carrying capacity for refrigerated cargo or fishing vessels with refrigerating plant for cooling or freezing catches of fish, the class notation RM(X°C/Y°C sea) as specified in Pt.6 Ch.4 Sec.10 may be assigned. For ships built and fully equipped for carriage of bananas and fruit in general under a controlled cargo chamber atmosphere in at least 50% of the ship's total refrigerated cargo chamber volume may be given the class notation CA as specified in the rules Pt.6 Ch.4 Sec.10 may be assigned. For ships built and equipped for carriage of bananas and fruit in general under a controlled cargo chamber atmosphere in at least 50% of the ship's total refrigerated cargo chamber volume except that a nitrogen generating unit and possibly parts of the alarm and monitoring equipment have not been permanently installed may be given the class notation CA(port.) as specified in the rules Pt.6 Ch.4 Sec.10 may be assigned. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 136

Part 5 Chapter 10 Section 15

SECTION 15 REFRIGERATED CARGO VESSELS

2.1 General 2.1.1 The ship shall be designed, arranged and equipped to make it suitable for cooling down and/or carrying cargo, freezing catches of fish etc. as relevant according to the design operating conditions specified by the builders and subsequently to be stated in the appendix to the classification certificate. The builders' and possible subcontractors' specifications of the ship's operational performances and abilities will together with the specific requirements of this chapter be used as basis for assignment of class.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 137

Part 5 Chapter 10 Section 15

2 Operational performance

1 General 1.1 Objective These rules establishes requirements for vessels intended to carry potable water in bulk.

1.2 Scope The rules in this chapter provide requirements to material, tank arrangement and piping systems with the objective of assuring transport in bulk of potable water with minimal risk of contaminating the cargo or otherwise reduce delivered quality. Guidance note: The quality of the water loaded may comply with the directive 98/83/EC of the European Union or with a quality standard specified by the receiving country or port. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.3 Application These rules apply to vessels dedicated to the transportation of potable water. The requirements shall be regarded as supplementary to those given for the assignment of main class.

1.4 Class notation Vessels complying with the requirements of this section may be assigned the class notation Tanker for potable water.

1.5 Assumption It is assumed that cargo tanks are not used for any other purpose than transport of potable water except under emergency conditions.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 138

Part 5 Chapter 10 Section 16

SECTION 16 TANKER FOR POTABLE WATER

2.1 General 2.1.1 The following plans and particulars shall be submitted: Table 1 Documentation Object

Documentation type

Additional description

Info

Including: General arrangement

Cargo piping arrangements

Cargo tank venting system

Cargo tank level measurement system

Z010 - General arrangement plan

- Cargo hatches, Butterworth hatches and any other opening to cargo tank.

FI

- Cargo pipes over the deck with shore connections including stern pipes for cargo discharge and loading.

S010 - Piping diagram (PD)

Including cargo stripping system. For vacuum stripping systems, details shall include termination of air pipes and openings from drain tanks and other tanks.

AP

C030 - Detailed drawing

Cargo pump (s)

AP

S010 - Piping diagram (PD)

AP

I200 - Control and monitoring system documentation

AP

Z030 - Arrangement plan Specification of tank coating with certificate of acceptance for toxicity and tainting testing by recognised laboratory or health authority

Z261 - Test report

Specifications of metallic and nonmetallic materials in contact with the cargo

M010 - Material specification, metals

Shall indicate type and location of level indicators.

FI

FI

Yard's declaration of materials in contact with cargo.

FI

2.1.2 For general requirements for documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. 2.1.3 For full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 2.1.4 For general requirement for documentation of instrumentation and automation, including computer based control and monitoring, see Pt.4 Ch.9 Sec.1 Table 5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 139

Part 5 Chapter 10 Section 16

2 Documentation

2.2.1 The following control and monitoring system shall be approved by the society: Documentation shall be submitted as required by Table 2 Table 2 Certification requirements Object

Certificate type

Issued by

Water quality instrument

PC

Society

Certification 1) standard

Additional description

1) Unless otherwise specified the certification standard is the Society`s rules. PC = product certificate, MC = material certificate, TR = test report

2.2.2 For full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 2.2.3 For full definition of certificate types, see Pt.1 Ch.3 Sec.4.

2.3 Surveys and Testing 2.3.1 General 2.3.1.1 All systems and installations covered by this section shall be surveyed and tested to the satisfaction of the surveyor.

3 Requirement for carriage of potable water 3.1 Material 3.1.1 Cargo piping and cargo tank materials 3.1.1.1 Materials in contact with water, including coatings are not to give off harmful substances in contact with water nor cause tainting or discoloration. 3.1.1.2 For non-metallic materials and coatings documentation showing their suitability for use in contact with water intended for human consumption shall be submitted, e.g. test documentation according to BS 6920 or equivalent.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 140

Part 5 Chapter 10 Section 16

2.2 Certification requirements

3.2.1 Cargo tanks 3.2.1.1 Cargo tanks shall be separated from tanks containing fuel oil, lubricating oil or any other liquid, except ballast water, by mean of cofferdams. 3.2.1.2 Cargo tanks shall be provided with means to guard against liquid rising in the venting system to a height which will exceed the design head of cargo tanks. This shall be accomplished by high level alarms or overflow control systems or other equivalent means. 3.2.2 Ballast tanks The vessel is to have sufficient segregated ballast capacity in order to enable safe operation under all conditions in normal operation of the vessel, i.e. sufficient for propeller submergence and draught forward in accordance with Pt.3 Ch.10.

3.3 Piping System 3.3.1 Cargo piping and tank vent 3.3.1.1 Cargo piping shall be separated from all other piping systems, i.e. no physical connection is allowed. 3.3.1.2 Tank vents shall be designed so as to prevent ingress of sea water. 3.3.1.3 The height of cargo tank vent outlets shall comply with load line requirements. 3.3.1.4 The venting system may consist of individual vents from each tank or vents from each individual tank may be connected to a common header. 3.3.1.5 Hydraulically operated valves are not to be located inside cargo tanks unless the hydraulic fluid used is harmless to the water quality in case a leakage should occur. 3.3.1.6 Submerged cargo pumps are not accepted if leakage of hydraulic fluid or lubricants may contaminate the cargo.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 141

Part 5 Chapter 10 Section 16

3.2 Tank Arrangement

July 2017 edition

Changes July 2017, entering into force 1 January 2018 Topic

Reference

Description

Methods for establishing escort rating number for escort tugs

Sec.11 [1.3] and Sec.11 [1.4]

Introduction of additional qualifiers and definitions

Sec.11 [6.8] to Sec.11 [6.10]

Introduction of additional qualifiers and definitions

Removed class requirements to tricing winch

Sec.11 [3.6.4] and Sec.11 [3.7.5]

Deletion of paragraph

winch drum requirements

Sec.11 [3.7.2]

For smaller tugs this requirement was not practicable due to smaller necessary winches.

Loadline requirements

Sec.11 [5.2]

Rephrased and aligned to general loadline requirements for ships and introduced special requirements for side scuttles and windows. Introduced special requirements for ventilation of machinery space applicable to small tugs and tugs in domestic trade.

Requirements to Propulsion system

Sec.11 [6.4]

Clarification and adding requirement for escort tugs

Restructuring of Section 11

Sec.11 [1.3.2]

Moved to Sec.11 [6.2.3]

Sec.11 [1.3.3]

Moved to Sec.11 [6.3.2]

Sec.11 [1.3.4]

Moved to Sec.11 [6.2.4]

Sec.11 [1.5]

Moved to Sec.11 [6.9] (including all sub-paragraphs)

January 2017 edition

Main changes January 2017, entering into force July 2017 • Sec.2 Crane vessels — Sec.2 [4.4.4]: Correction has been made to the explanation of ARL and AHL.

• Sec.10 Icebreaker — Sec.10 [5.1]: Table reference Pt.6 Ch.6 Sec.5 Table 8 has been added to be aligned with Pt.6 Ch.6 Sec.5. — Sec.10 Table 1: Minor adjustments have been made to be aligned with IACS Polar class requirements, UR 12.

July 2016 edition

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 142

Part 5 Chapter 10 Changes – historic

CHANGES – HISTORIC

• Sec.1 General — Sec.1 [2.1]: Class notation Pipe laying vessel is added to the table.

• Sec.5 Semi-submersible heavy transport vessel — Sec.5 [2.1]: Changing acceptance criteria to AC-II, with reduced dynamic wave loads in temporarily submerged condition and in aft loading/aft-unloading condition (non-submerged condition). Permissible stresses will be based on AC-II. — Sec.5 [2.2]: Changing acceptance criteria to AC-II, with reduced dynamic wave loads in temporarily submerged condition and in aft loading/aft-unloading condition (non-submerged condition). Permissible stresses will be based on AC-II. — Sec.5 [2.3]: Changing acceptance criteria to AC-II, with reduced dynamic wave loads in temporarily submerged condition and in aft loading/aft-unloading condition (non-submerged condition). Permissible stresses will be based on AC-II. — Sec.5 [2.4]: Changing acceptance criteria to AC-II, with reduced dynamic wave loads in temporarily submerged condition and in aft loading/aft-unloading condition (non-submerged condition). Permissible stresses will be based on AC-II.

• Sec.7 Seismographic research vessels — Sec.7 [3.1.2]: Improvement of the minimum GM value used in racking analysis is needed to be in line with minimum value given in Pt.3 Ch.4. Some minor improvement and clarifications of the racking moment calculation is also needed. — Sec.7 [3.1.3]: Correction typo. — Sec.7 [3.1.5]: Missing requirement related to general FE load application included. — Sec.7 [3.2.2]: Requirements for design load sets for beam analysis has been included. — Sec.7 [3.2.3]: New paragraph: Design Load sets for beam analysis.

• Sec.10 Icebreaker — Sec.10 [3.2]: Figure 1 has been amended with respect to hull area extensions for aft ship region in order to get it aligned with the rule text given in [3.2]. — Sec.10 [5.1]: Hull Area Factors (AF) for ships with class notation Icebreaker with thrusters/podded propulsion.

• Sec.12 Dredgers — Sec.12 [2.6.3]: The January 2016 version was missing the requirements to brackets in double bottom. During the merging of the LGL rules these requirements were by mistake forgotten. The requirements are still valid. — Sec.12 [2.6.6]: New paragraph: Brackets.

• Sec.14 Slop reception vessel — Sec.14 [1.3.2]: Requirements for Slop Reception Vessels are included in the rules due to customer interest (copied from legacy DNV Rules). — Sec.14 [2.1.3]: New requirement regarding compliance with MARPOL AnnexI.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 143

Part 5 Chapter 10 Changes – historic

Main changes July 2016, entering into force as from date of publication

A section Refrigerated Cargo Vessels is included in the Rules due to customer interest in Fruit Juice Carriers and other refrigerated fruit vessels.

January 2016 edition This document supersedes the October 2015 edition.

Main changes January 2016, entering into force as from date of publication • Sec.10 Icebreaker — [5]: Old Table 1 is deleted since the ramming speed, Vram, is not applied in any formula. — Table 2: Hull area factors for podded/thruster propulsion was missing and is now included. — [7.2]: The requirements for overall strength of substructure in the fore ship has been amended.

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.10. Edition January 2018 Vessels for special operations

DNV GL AS

Page 144

Part 5 Chapter 10 Changes – historic

• Sec.15 Refrigerated cargo vessels

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition July 2017

Part 5 Ship types Chapter 11 Non self-propelled units

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS July 2017

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

Part 5 Chapter 11 Changes - current

CHANGES – CURRENT This document supersedes the July 2016 edition of DNVGL-RU-SHIP Pt.5 Ch.11. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes July 2017, entering into force 1 January 2018 Topic Introduction of the significant wave height to reduce scantling requirements.

Error corrections and clarifications

Reference

Description

Sec.2 [4.1]

Introduction of wave loads definition.

Sec.2 [5.1]

Alignment to significant wave height approach.

Sec.2 [5.2]

Deletion.

Sec.2 Table 1

Deletion.

Sec.2 [9.1]

Alignment to significant wave height approach.

Sec.2 [3]

Introduction of material requirements.

Sec.2 [5.1.3]

Align to Pt.3 and fine tuning of hull girder section modulus.

Sec.3 [2.1]

First paragraph deleted.

Sec.3 [2.1.1]

Text clarified.

Sec.3 [2.1.4]

Part of the text deleted.

Sec.3 [2.1.5]

Part of the text deleted.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 3

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................... 7 1 Introduction.........................................................................................7 1.1 Introduction..................................................................................... 7 1.2 Scope..............................................................................................7 1.3 Application....................................................................................... 7 2 Class notations.................................................................................... 8 2.1 Ship type notations.......................................................................... 8 2.2 Additional class notations.................................................................. 8 3 Definitions........................................................................................... 9 3.1 Terms..............................................................................................9 4 Documentation.....................................................................................9 4.1 Documentation requirements............................................................. 9 5 Certification....................................................................................... 12 5.1 Certification requirements................................................................ 12 6 Testing............................................................................................... 12 6.1 Testing during newbuilding for concrete barges...................................12 Section 2 Hull........................................................................................................ 13 1 General arrangement design............................................................. 13 1.1 Subdivision arrangement................................................................. 13 2 Compartment arrangement................................................................13 2.1 Bottom structure............................................................................ 13 3 Structural design principles............................................................... 13 3.1 Material......................................................................................... 13 3.2 Main deck...................................................................................... 13 3.3 Bottom structure............................................................................ 14 4 Loads................................................................................................. 14 4.1 Wave Loads....................................................................................14 4.2 Deck loading.................................................................................. 14 4.3 Airoverpressure...............................................................................14 5 Hull girder strength........................................................................... 15 5.1 Main section modulus.................................................................... 15 5.2 Split hopper barges.........................................................................16 6 Hull local scantling............................................................................ 18 6.1 Deck structure................................................................................18

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 4

Part 5 Chapter 11 Contents

CONTENTS

7.1 Stresses based on direct strength analysis......................................... 18 8 Fatigue strength................................................................................ 18 8.1 Application..................................................................................... 18 9 Special requirements......................................................................... 18 9.1 Fore peak...................................................................................... 18 9.2 Bottom slamming............................................................................19 9.3 Supporting structure of towing equipment......................................... 19 10 Pusher/barge or pusher/pontoon units........................................... 19 10.1 Subdivision arrangement................................................................19 10.2 Hull girder strength....................................................................... 19 10.3 Hull local scantling........................................................................ 19 10.4 Special requirements - connecting elements..................................... 20 10.5 Special requirements - ice strengthening......................................... 21 Section 3 Systems and equipment........................................................................ 22 1 Steering arrangement........................................................................ 22 1.1 General requirements...................................................................... 22 2 Anchoring and mooring equipment....................................................22 2.1 General requirements...................................................................... 22 2.2 Pusher/barge and pusher/pontoon units............................................ 22 3 Machinery, systems and electrical installations................................. 23 3.1 General requirements...................................................................... 23 3.2 Pusher/barge and pusher/pontoon units............................................ 23 Section 4 Safety and lifesaving appliances........................................................... 24 1 General safety requirements............................................................. 24 1.1 General..........................................................................................24 2 Fire safety..........................................................................................24 2.1 General requirements...................................................................... 24 3 Power supply..................................................................................... 24 3.1 General requirements...................................................................... 24 4 Radio communication.........................................................................25 4.1 General requirements...................................................................... 25 5 Lifesaving appliances.........................................................................25 5.1 General requirements...................................................................... 25 Section 5 Stability and opening and closing appliances........................................ 27 1 Stability............................................................................................. 27 1.1 General requirements...................................................................... 27

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 5

Part 5 Chapter 11 Contents

7 Buckling............................................................................................. 18

2.1 Drainage........................................................................................ 27 2.2 Hatches and deck openings..............................................................28 2.3 Bow height.................................................................................... 28 Section 6 Concrete hull (TENTATIVE RULES)........................................................ 29 1 Materials............................................................................................ 29 1.1 General requirements...................................................................... 29 2 Design principles............................................................................... 30 2.1 General requirements...................................................................... 30 3 Loads................................................................................................. 31 3.1 Local loads.....................................................................................31 3.2 Hull girder loads............................................................................. 33 4 Design resistance.............................................................................. 33 4.1 General requirements...................................................................... 33 5 Survey and testing............................................................................ 34 5.1 Survey and testing during newbuilding of concrete barges....................34 5.2 Survey and testing after delivery of concrete barges........................... 35 Changes – historic................................................................................................ 36

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 6

Part 5 Chapter 11 Contents

2 Opening and closing appliances.........................................................27

Symbols For symbols and definitions not defined in this section, see Pt.3 Ch.1 Sec.4.

1 Introduction 1.1 Introduction 1.1.1 These rules provide requirements for vessels intended to be operated as barges or pontoons.

1.2 Scope 1.2.1 These rules include requirements for strength for both steel and concrete hull, hatches and deck openings, systems and equipment, stability and load line, and the relevant procedural requirements applicable to barges and pontoons. For barges intended to carry personnel, the scope also covers basic safety requirements. This includes fire safety, life saving appliances, power supply, and radio communication.

1.3 Application 1.3.1 The requirements in this chapter shall be regarded as supplementary to those given for the assignment of class rules Pt.2, Pt.3 and Pt.4 applicable for the assignment of main class. 1.3.2 Vessels built in compliance with the relevant requirements in this chapter may be given the mandatory class notation Barge or Pontoon. Vessels built in compliance with the relevant additional requirements in [2] of this chapter may be given the class notation Barge(Hopper). Vessels built in compliance with the relevant additional requirements in [6] of this chapter may be given the class notation Barge(Concrete).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 7

Part 5 Chapter 11 Section 1

SECTION 1 GENERAL

2.1 Ship type notations 2.1.1 Vessels built in compliance with the requirements as specified in Table 1 will be assigned the class notations as follows: Table 1 Ship type notations Class notation

Barge

Description

Qualifier

Barges are vessels <none> without sufficient means of selfpropulsion for transit. Assistance from another Hopper vessel during transit or transportation service is 1 assumed.

Vessels without cargo hold and no means Pontoon of self-propulsion for transit.

Additional description

Design requirements, rule reference Sec.1 to Sec.5

3

<none>

Barge primarily designed for selfunloading where the port and starboard portions are hinged at the hopper end bulkheads to facilitate rotation around the longitudinal axis when the bottom opens Vessel specifically intended for carriage of cargo on deck only

Sec.1 to Sec.5

Sec.1 to Sec.5

1)

Guidance note: For vessels with limited means of self-propulsion an upper limit for barges/pontoons may normally be taken as machinery output giving a maximum speed less than V = 3 + L/50 knots, L not to be taken greater than 200 m.

2)

Barge made of concrete will be assigned the class notation: Barge(Concrete). The survey related class notation BIS is mandatory and requirements given in Pt.6 Ch.9 Sec.1 shall be complied with.

3)

Hopper is an optional qualifier for barges built for dredging operations, i.e. Barge(Hopper).

2.2 Additional class notations 2.2.1 The following additional notations, as specified in Table 2, are typically applied to barges and pontoons: Table 2 Additional class notations Class notation

Description

Application

Strengthened(DK)

Decks strengthened for heavy cargo

All ships

R0, R1, R2, R3, R4, RE

Service area notation

All ships

Guidance note: Independent of the service area notation, a barge or pontoon may be designed for a significant wave height HS, specified by the designer. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.2 For a full definition of all additional class notations, see Pt.1 Ch.2.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 8

Part 5 Chapter 11 Section 1

2 Class notations

3.1 Terms Table 3 Definitions Terms

Definition an unmanned or manned vessel, without sufficient means for self-propulsion, sailing in pushed or towed units with following characteristics:

barges

— the ratios of the main dimensions may deviate from those usual for seagoing ships — the cargo holds are suitable for the carriage of dry or liquid cargo. an unmanned or manned vessel, without self-propulsion with following characteristics:

pontoons

— the ratios of the main dimensions deviate from those usual for seagoing ships

hopper barge

a self-unloading barge where the port and starboard portions are hinged at the hopper end bulkheads to facilitate rotation around the longitudinal axis when the bottom opens.

— it is designed to carry deck load or working equipment, e.g. lifting equipment, rams etc. on deck only and have no holds for the carriage of cargo.

4 Documentation 4.1 Documentation requirements 4.1.1 General For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 4.1.2 Barges and pontoons Documentation shall be submitted as required by Table 4. Table 4 Documentation requirements Object

Documentation type

Additional description

Info

Towing arrangement Z030 – Arrangement plan

Arrangement of towing line, fastening arrangement and details.

FI

Towing equipment supporting structures

Including towing force design loads and winch load footprint.

AP

H050 - Structural drawing

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

4.1.3 Additional documentation For barges and pontoons, carrying 36 persons or more the following additional following documentation shall be submitted as required by Table 5. For class notation qualifier Concrete, additional documentation shall be submitted as required by Table 6.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 9

Part 5 Chapter 11 Section 1

3 Definitions

Object

Documentation type

Additional description

Info

G040 – Fire control plan

AP

G050 – Safety control plan

AP

G060 – Structural fire protection drawing

AP

G061 – Penetration drawings

AP

I200 – Control and monitoring system documentation

AP

Z030 – Arrangement plan

AP

S010 – Piping diagram (PD)

AP

S030 – Capacity analysis

AP

Z030 – Arrangement plan

AP

Fixed fireextinguishing systems

G200 – Fixed fire extinguishing system documentation

AP

Escape routes

G120 – Escape route drawing

AP

S012 - Ducting diagram (DD)

AP

S014 - Duct routing sketch

AP

G160 – Life-saving arrangement plan

AP

Safety general Structural fire protection arrangements Fire detection and alarm system

Fire water system

Ventilation systems Life-saving appliances

AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 10

Part 5 Chapter 11 Section 1

Table 5 Documentation requirements - Class notation Barge or Pontoon carrying 36 persons or more

Object

Documentation type

Additional description

Info

Including: H010 – Structural design brief

— overall design safety — functional requirements

FI

— material data — design phases. Including: H020 – Design load plan

— self-weight distribution

FI

— accidental loads. Including: — reinforcement in structural members H050 – Structural drawing Hull structure

— reinforcement details — position and density of pre-stressing arrangement

AP

— pre-stressing anchorage details. Including: H080 – Strength analysis

— combination of local and global loads for different limit states

FI

— calculationof the utilisation of the structural elements in the different limit states. Z164 - Inspection manual

For in-service inspection, based on design and construction considerations.

AP

Q010 – Quality manual

Documenting valid EN ISO 9001 certificate or equivalent.

FI

Z260 – Report

Deviation reports and their closure documentation.

AP

Including: — qualification testing of the concrete Structural fabrication

— construction procedures H130 – Fabrication specification

— formwork — concreting

FI

— procedure for taking control specimens and testing of these — procedure for curing of the concrete. AP = For approval; FI = For information ACO = As carried out; L = Local handling; R = On request; TA = Covered by type approval; VS = Vessel specific

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 11

Part 5 Chapter 11 Section 1

Table 6 Documentation requirements - For class notation qualifier Concrete

Part 5 Chapter 11 Section 1

5 Certification 5.1 Certification requirements 5.1.1 General For a definition of the certificate types, see Pt.1 Ch.3 Sec.5. 5.1.2 Barges Products for Barge(Concrete) shall be certified as required by Table 7. Table 7 Certification requirements Certificate type

Issued by

Concrete materials

MC

Society

Anchorage devices and mechanical splices

MC

Society

Object

Certification standard*

Additional description

See DNV-OS-C502 Sec.4 G200

* Unless otherwise specified the certification standard is the rules

6 Testing 6.1 Testing during newbuilding for concrete barges 6.1.1 Testing requirements for class notation Barge(Concrete) is given in Sec.6 [5].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 12

Symbols For symbols and definitions not defined in this section, see Pt.3 Ch.1 Sec.4.

1 General arrangement design 1.1 Subdivision arrangement 1.1.1 Watertight bulkhead arrangement A watertight bulkhead shall be fitted at both ends of the hold area. In the remaining part of the hull, watertight bulkheads shall be fitted as required for the purpose of watertight subdivision and for transverse strength. For barges and pontoons with length LLL ≥ 100 m and with discharging arrangements in the bottom, the regions having such bottom openings shall be bounded by watertight transverse bulkheads from side to side. 1.1.2 Collision bulkhead Barges and pontoons shall have a collision bulkhead and an after end bulkhead. For barges and pontoons with LLL ≥ 100 m, the position of the collision bulkhead shall be determined according to Pt.3 Ch.2 Sec.2 [4].

2 Compartment arrangement 2.1 Bottom structure 2.1.1 The bottom structure may be built as single or double bottom. In case the barge is arranged with a double bottom refer to requirements given in Pt.3 Ch.2 Sec.3 [2] and Pt.3 Ch.3 Sec.5 [3]. The height of a double bottom shall give good access to all internal parts. The height shall not be less than 650 mm.

3 Structural design principles 3.1 Material 3.1.1 The material requirements of Pt.3 Ch.3 Sec.1 apply in general. 3.1.2 For non self-propelled box shaped pontoons, closed barges and similar units, material grade A/AH is generally acceptable.

3.2 Main deck 3.2.1 If the deck will be subjected to heavy point loads, plans shall be submitted showing the arrangement and position of loads as well as their magnitude. It shall be specified if all loading points will be subject to loads simultaneously, or if there will be some alternative groupings of the loads. For reduction of dynamic loads, see Table 1. Heavy point loads should preferably be supported directly by bulkheads. Decks subject to wheel loads shall have scantlings complying with requirements given in Pt.3 Ch.10 Sec.5. Dry cargo barges where the cargo holds and the main deck are supported by cantilevers are to comply with requirements given in Ch.1 Sec.5.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 13

Part 5 Chapter 11 Section 2

SECTION 2 HULL

The bottom structure shall be considered as a grillage system being supported by ship sides and/or bulkheads.

4 Loads 4.1 Wave Loads 4.1.1 The wave loads shall in general be taken in accordance with Pt.3 Ch.4 Sec.2. 4.1.2 Vessels may be designed with a specified maximum significant wave height HS as an operational limitation. When HS is specified, the dynamic loads given in Pt.3 Ch.4 and gross section modulus requirement in [5.1.1] may be reduced with the factor fr.

Guidance note: The maximum significant wave height, HS, will be specified as an operational limitation in the appendix to classification certificate. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.3 For vessels with service area notation, the corresponding significant wave height HS as given in Pt.1 Ch.2 Sec.5 Table 1 shall be applied, unless otherwise specified by the designer according to [4.1.2].

4.2 Deck loading 2

The uniform deck loading (UDL) for cargo deck shall not be taken less than 0.7 t/m .

4.3 Airoverpressure Where tanks are intended to be emptied by compressed air, the maximum airoverpressure shall replace PPV in the formulae for determining the pressures Pls in Pt.3 Ch.4 Sec.6 [1.2], for the static (S) load scenario. Guidance note: The maximum airoverpressure applied in the design and used as approval basis will be stated in the appendix to classification certificate. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 14

Part 5 Chapter 11 Section 2

3.3 Bottom structure

5.1 Main section modulus 5.1.1 The minimum midship gross section modulus shall not be less than the value obtained from the following formula:

where:

fr C WO

= reduction factor related to limitation on maximum significant wave height as defined in [4.1.2] = wave parameter, as defined in Figure 1 and [5.2.1].

11 10 9 8 7 6 5 4 3 2 1 0

Figure 1 Wave coefficient 5.1.2 The gross hull girder section modulus shall comply with the requirements given in Pt.3 Ch.5 Sec.2 [1.4.1], but with the following permissible stresses:

σperm = permissible hull girder bending stress, in kN/m2, to be taken as: for for

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 15

Part 5 Chapter 11 Section 2

5 Hull girder strength

Intermediate values of

σperm shall be obtained by linear interpolation.

5.1.3 Split hopper barges Split hopper barges longitudinal hull girder strength calculations shall be carried out for the unloading condition according to [5.2]. 5.1.4 Special harbour conditions For special harbour conditions, e.g. transient states when moving heavy structures on board from end of barge, or when the wave heights are considered to be negligible, the wave bending moment may be taken zero when calculating hull girder section modulus, see [5.1.2].

5.2 Split hopper barges 2

5.2.1 For unloading condition of split hopper barges, the following stresses, in N/mm , in the split hopper area for still water condition and HSM and FSM load cases shall be considered as follows:

M’y-sw M’z-sw

= still water bending moments, in kNm, related to the inertia axis y'-y' and z'-z' respectively, as shown in Figure 2

M’z-dyn

= bending moments related to external hydrodynamic pressure for HSM and FSM load cases, in kNm, related to the inertia axis y'-y' and z'-z' respectively as shown in Figure 2, to be taken as:

I’y-n50 I’z-n50

= moments of inertia of the cross section shown in Figure 2 related to the respective 4 inertia axis, in m

ey', ez'

= distances of the position being considered to the inertia axis y'-y' and z'-z' respectively, in m

P

= external hydrodynamic pressure, in kN/m , for TSC, for HSM and FSM load cases as defined in Pt.3 Ch.4 Sec.5 [1.3]

w

ℓh h ρ P

2

= spacing, in m, between hinges = cargo height, in m, as shown in Figure 2 3

= design cargo density, in t/m , not to be taken less than 1.2 L

2

= static design cargo pressure, in kN/m , shall be taken as:

The stresses in the split hopper area shall be determined for the most unfavourable distribution of cargo and consumables.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 16

Part 5 Chapter 11 Section 2

for

y'

h TSC y'

PL PW PW z'

Figure 2 Static loads on a self-unloading barge, loaded. 2

5.2.2 The hull girder stresses combined with stresses in the split hopper area, in N/mm , shall satisfy the following criteria:

where: 2

σ

hg-sw

= hull girder stress, in N/mm , due to vertical still water bending moment as defined in Pt.3 Ch.5 Sec.1 [5].

σ

hg-dyn

= hull girder stress, in N/mm , for HSM and FSM load cases as defined in Pt.3 Ch.5 Sec.1 [5].

2

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 17

Part 5 Chapter 11 Section 2

z'

where:

σ τ

b

2

= bending stress, in N/mm . 2

= shear stress, in N/mm .

6 Hull local scantling 6.1 Deck structure If the deck girders constitute a grillage system, direct strength calculations according to Pt.3 Ch.6 Sec.6 shall be made applying the design load sets specified in Pt.3 Ch.6 Sec.2 (or other specified design load sets given by the designer), to verify that the stress criteria given in Pt.3 Ch.6 Sec.6 [2.2] are complied with.

7 Buckling 7.1 Stresses based on direct strength analysis The normal stresses and shear stress taken from direct strength assessment to be applied for buckling capacity calculation of plate panels (see Pt.3 Ch.8) shall be corrected as given in DNVGL-CG-0128 Sec.3.

8 Fatigue strength 8.1 Application Fatigue strength calculations shall be performed for barges and pontoons being operated as an offshore installation, e.g. fixed to a specific oil field for longer periods with no possibilities for survey and intended to operate in harsh weather conditions. For such units, verification of fatigue strength is required when their length exceeds 150 m. If applicable, all longitudinal strength members on external shell and deck shall be verified for compliance with the prescriptive fatigue strength requirements in Pt.3 Ch.9.

9 Special requirements 9.1 Fore peak Barges and pontoons with unrestricted operations, shall be checked for bow impact according to Pt.3 Ch.10 Sec.1. If necessary, both ends shall be reinforced, see also [1.1.1].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 18

Part 5 Chapter 11 Section 2

5.2.3 Stresses in the bearing seating and all other members of the hinge shall satisfy the following criteria:

The bottom in barges and pontoons with L > 100 m shall be strengthened against slamming, see Pt.3 Ch.10 Sec.2. In the formula for CSL-et and CSL-ft the ballast draught TF-e and TF-f may be substituted by full draught T.

9.3 Supporting structure of towing equipment Towing hooks, winches and brackets with their supporting structure shall be capable of withstanding the breaking load Pb of the towline. The breaking load Pb shall not be taken less than the towline minimum breaking strength given in Pt.3 Ch.11 Sec.1 Table 1 in Pt.3 Ch.11 Sec.1 [3]. Acceptable stress levels in the supporting structure resulting from bending moments and shearing forces calculated for the load Pb are:

where:

σb τ σvm

2

= bending stress, in N/mm = shear stress, in N/mm

2

= combined stress, in N/mm

2

10 Pusher/barge or pusher/pontoon units 10.1 Subdivision arrangement 10.1.1 Collision bulkhead The barge/pontoon is at least to have a collision bulkhead between 0.05 L and 0.08 L from F.P. and an after peak bulkhead at a suitable distance forward of the connection area.

10.2 Hull girder strength The longitudinal strength shall comply with the requirements given in Pt.3 Ch.5. For the combined pusher/ barge unit or pusher/pontoon unit of type I the longitudinal strength of the barge/pontoon shall be based on a length L as given in Pt.3 Ch.1 Sec.4 [3] measured between the bow of the barge/pontoon and the stern of the pusher.

10.3 Hull local scantling 10.3.1 Structural members are in general to comply with the rule requirements for hull structures in Pt.3 based on the rule length of the combined unit.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 19

Part 5 Chapter 11 Section 2

9.2 Bottom slamming

10.4 Special requirements - connecting elements 10.4.1 The pusher and the aft part of the barge/pontoon shall be so designed as to allow the pusher to interact with the stern area of the barge/pontoon. The mutual forces between the two structures shall be transferred by a system of contact surfaces. The connection of type I shall be secured by at least one mechanical locking device. For type II a flexible connection shall be provided. 10.4.2 The connection forces shall be based on the most severe load conditions to be expected in service. Wave-induced loads shall be determined according to accepted theories, model tests or full scale measurements. The loads shall be referred to extreme wave conditions, which should be based upon wave statistics for the expected route or service area, in case of restricted service. For unlimited worldwide service North Atlantic 8 wave statistics shall be used. The resulting loads shall be given as long term values corresponding to 10 -8 wave encounters (most probable largest loads at a probability of exceedance equal to 10 ). Realistic conditions with respect to speed and navigation in heavy weather shall be considered, also taking into account the general assumption of competent handling. 10.4.3 Direct calculations shall be made in order to evaluate the stresses in all relevant strength members of the connection between barge/pontoon and pusher. Shearing forces and or longitudinal bending moments in the sections in question are found from direct calculations for barge/pontoon and pusher in still water and in waves. Pre-loading from locking devices is also to be taken into account. 2

The stresses in the connection, in N/mm , for the static plus dynamic (S+D) design load scenario shall not exceed the following permissible values:

For forged and cast steel parts, k, shall be taken as:

10.4.4 All relevant strength members shall have effective continuity, and details which may cause stress concentration shall have gradual transitions. 10.4.5 Deflections of the structural parts in the connection structure and the necessary pre-loading shall be considered in order to avoid hammering when the most unfavourable reaction forces occur. Calculations of these deflections shall be submitted. 10.4.6 Locking devices and or other connection equipment are subject to approval. If based on hydraulic operation the connecting system shall be mechanically lockable in closed position with remote indication on the bridge.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 20

Part 5 Chapter 11 Section 2

10.3.2 Scantlings of the after body of the barge/pontoon are in no case to be less than required for the barge/pontoon in unconnected condition.

10.5.1 Pusher/barge units or pusher/pontoon units with type I connection system may be given an ice class notation provided relevant requirements given in Pt.6 Ch.6 regarding machinery and hull strengthening are complied with. 10.5.2 The requirements to machinery (in the pusher) and hull strengthening shall be based on a displacement which is the sum of the displacements of barge/pontoon and pusher. 10.5.3 The hull strengthening of the exposed part of the pusher shall comply with the requirements for the aft end of the combined pusher/barge unit or pusher/pontoon unit.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 21

Part 5 Chapter 11 Section 2

10.5 Special requirements - ice strengthening

1 Steering arrangement 1.1 General requirements 1.1.1 If rudder is installed, the steering arrangement shall comply with the requirements given in Pt.3 Ch.14 Sec.1 as far as these rules are found to be relevant for barges and pontoons. When calculating the rudder force, the speed shall not be taken less than 8 knots.

2 Anchoring and mooring equipment 2.1 General requirements 2.1.1 For manned barges and pontoons with equipment number EN less than 205 the anchor and chain equipment specified in Pt.3 Ch.11 Sec.1 Table 1 may be reduced, on application from the owners, based upon a special consideration of the intended service area of the vessel. The reduction shall not be more than given for the service notation R4 in Pt.3 Ch.11 Sec.1 Table 3. 2.1.2 Unmanned barges and pontoons may be accepted without anchoring equipment installed. 2.1.3 The equipment number EN for determining the equipment according to Pt.3 Ch.11 Sec.1 Table 1 shall be determined for pontoons carrying lifting equipment, rams etc. by the following formula: EN = Δ

Δ fb fw

2/3

+ B · fb + fw

= displacement of the pontoon, in t, at maximum anticipated draught = distance, in m, between pontoon deck and waterline

2

= wind area of the erections on the pontoon deck, in m , which are exposed to the wind from forward, including houses and cranes in upright position.

2.1.4 In special cases, upon owner’s request, for manned pontoons the number of anchors may be reduced to one and the length of the chain cable to 50% of the length required by Pt.3 Ch.11 Sec.1 Table 1. 2.1.5 If necessary for a special purpose, for pontoons mentioned under [2.1.4], the anchor mass may be further reduced by up to 20%. Upon owner’s request the anchor equipment may be dispensed with. If not equipped with anchoring equipment, this will be stated in the appendix to the class certificate. 2.1.6 If a steel wire rope shall be provided instead of a stud link chain cable on manned barges and pontoons, the requirements given in Pt.3 Ch.11 Sec.1 [5] shall be complied with. 2.1.7 Anchor equipment fitted in addition to that required herein, e.g. for positioning purposes, is not part of classification.

2.2 Pusher/barge and pusher/pontoon units The pusher/barge or the pusher/pontoon unit shall have equipment corresponding to an equipment number which shall be calculated for the combined pusher/barge or pusher/pontoon unit according to Pt.3 Ch.11 Sec.1 [3].

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 22

Part 5 Chapter 11 Section 3

SECTION 3 SYSTEMS AND EQUIPMENT

3.1 General requirements 3.1.1 If the barge or pontoon is arranged with machinery and electrical installations, relevant requirements given in Pt.4 shall be complied with.

3.2 Pusher/barge and pusher/pontoon units 3.2.1 Machinery, bilge system, fire extinguishing plant Machinery, pumps, piping systems, fitting, materials, bilge system and fire extinguishing plant shall comply with Pt.4, as relevant for barges/pontoons.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 23

Part 5 Chapter 11 Section 3

3 Machinery, systems and electrical installations

1 General safety requirements 1.1 General 1.1.1 For barges and pontoons designed to carry 36 persons or more the safety requirements in this section shall apply. 1.1.2 The yard or builder shall submit evidence of these topics being accepted by the respective Administration, in which the same will be also be acceptable to the Society. 1.1.3 For manned barges and pontoons with less than 36 persons, the requirements herein will be reviewed on a case by case basis.

2 Fire safety 2.1 General requirements 2.1.1 In absence of specific safety requirements from the respective flag administration, the barge shall comply with the cargo ship fire safety requirements of Ch.II-2 of SOLAS 1974 as amended.

3 Power supply 3.1 General requirements 3.1.1 For barges and pontoons with a power generation plant, at least two main generator sets shall be provided. The capacity shall be sufficient to maintain the barge in normal operational conditions with any one main generator out of operation. 3.1.2 A self-contain emergency source of power shall be provided. The emergency source of power and its associated equipment shall be located on or above the freeboard deck, and independent of the main electrical power required by [3.1.1]. 3.1.3 The requirements for a separate emergency source of power may be omitted for installations with two independent engine rooms when compliant with Pt.4 Ch.8 Sec.2 [3.1.4]. 3.1.4 In case of failure in the main source of electrical power, the emergency source of power shall be automatically connected to the emergency switchboard unless a transitional source of power is provided. The emergency source of power shall be capable of supplying simultaneously the services listed for at least 18 hours — — — — — — —

emergency lighting for machinery spaces, control stations, alleyways, stairways, exits and elevators emergency lighting for embarkation stations on decks and over sides emergency lighting for stowage position(s) for firemen’s outfits emergency lighting for helicopter landing decks navigation and special purpose lights and warning systems including helicopter landing lights general alarm and communications systems fire detection and alarm systems

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 24

Part 5 Chapter 11 Section 4

SECTION 4 SAFETY AND LIFESAVING APPLIANCES

3.1.5 The transitional source of power, if required, shall be capable of supplying the services listed for at least 30 minutes: — emergency lighting — general alarm and communications systems — fire detection and alarm systems. 3.1.6 The electrical installation shall comply with relevant requirements given in Pt.4 Ch.8.

4 Radio communication 4.1 General requirements 4.1.1 In absence of specific radio communication requirements from the respective flag administration, the barge shall be provided with a radio-telephone station complying with the provision of Chapter IV of SOLAS 1974 as amended and at least one emergency position-indicating radio beacon (EPIRB). 4.1.2 The radio station shall be subject to survey by the administration which issue the licence or its authorised representative before the radio station is put into service. 4.1.3 The radio station shall be surveyed once every 12 months, carried out by an officer of the Administration or its authorised representative, or by a qualified radio service engineer from a local radio firm approved by the Society.

5 Lifesaving appliances 5.1 General requirements 5.1.1 In absence of specific lifesaving appliances requirements from the respective flag administration, the barge is to comply with the requirements given in Part A and Section I of Part B of Ch.III of SOLAS 1974, as amended, and with the applicable provisions of the International Life-Saving Appliance (LSA) Code. Furthermore, under the same condition the articles [5.1.2] to [5.1.7] will also apply. 5.1.2 The barge shall carry one or more lifeboats complying with the requirement of section [4.6], [4.7], [4.8] and [4.9] of the LSA Code of such aggregate capacity on each side of the ship as will accommodate at least 50% of all persons onboard. 5.1.3 In addition, inflatable or rigid liferafts complying with the requirement of section [4.2] and [4.3] of the LSA Code, of such aggregate so that there will be survival craft on each side of the barge to accommodate all persons onboard. 5.1.4 In lieu of the requirement in [5.1.2] and [5.1.3], barges and pontoons of less than 85 m in length or barges and pontoons with appropriate damage stability as per SOLAS SPS Code, may carry on each side of the barge one or more life rafts complying with the requirement of section [4.2] and [4.3] of the LSA Code of such aggregate as will accommodate all persons onboard. 5.1.5 The barge shall carry at least one rescue boat complying with the requirement of section 5 of the LSA Code. 5.1.6 Personal life-saving appliances shall comply with requirements given in SOLAS Reg.III/32.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 25

Part 5 Chapter 11 Section 4

— fire extinguishing systems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 26

Part 5 Chapter 11 Section 4

5.1.7 Survival craft embarkation and launching arrangement shall comply with requirements given in SOLAS Reg.III/33.

1 Stability 1.1 General requirements 1.1.1 Barges or pontoons with a length LLL of 24 m and above shall comply with the intact stability requirements according to Pt.3 Ch.15. 1.1.2 The alternative stability criteria as given in 2008 IS Code Part B Ch.2.2 may be applied for vessels with class notations Barge, Pontoon or Barge(Concrete) for which the application requirements of 2008 IS Code Part B Ch.2.2.1 are met. 1.1.3 Vessels with class notation Barge(Concrete) shall be capable of surviving a minor hull damage that results in flooding of any one compartment bounded by the shell. The minor damage should be assumed to occur anywhere in the length of the barge, but not on a watertight bulkhead or deck. The barge's survival capabilities after the specified damage shall be in accordance with the damage stability criteria of IMO resolution MSC.235(82) chapter 3.3. Other recognized international damage stability standards may however be accepted as an alternative to IMO resolution MSC.235(82) subject to agreement with the Society.

2 Opening and closing appliances 2.1 Drainage 2.1.1 Barges or pontoons are normally to be provided with means for drainage of cargo holds, engine rooms and watertight compartments and tanks which give major contribution to the vessel's buoyancy and floatability. 2.1.2 As far as applicable and with the exemptions specified in the following, the rules and principles for drainage of ship with propulsion machinery shall be complied with. 2.1.3 Manned barges and pontoons shall be provided with a permanently installed bilge system with power bilge pumps. The bilge system shall have suctions in rooms mentioned in [2.1.1]. An additional emergency bilge suction shall be provided in engine rooms. Dry compartments in fore- and after peaks may be drained by effective hand pumps. Rooms situated on deck may be drained directly overboard. 2.1.4 Manned barges and pontoons for unlimited service shall be equipped with two permanently installed bilge pumps. Manned barges and pontoons with restricted service may have one bilge pump. Ballast pumps may be used as bilge pumps. Where only one permanently installed bilge pump is installed, this pump shall not serve as fire pump. 2.1.5 Ballast systems shall comply with the requirements for ballast systems in ships. However, one ballast pump may be accepted. Alternative methods for emptying ballast tanks, e.g. by means of compressed air and bottom valves, may be accepted upon consideration in each case.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 27

Part 5 Chapter 11 Section 5

SECTION 5 STABILITY AND OPENING AND CLOSING APPLIANCES

For cargo holds the facilities shall be so arranged that drainage can be performed in loaded conditions, for instance by arranging ducts for portable pumps to bilge wells or piping from the connection point of the bilge pump to the bilge wells. Other compartments which shall be drained by portable equipment shall be provided with suitable access openings for such equipment. Any engine room or pump room shall have bilge suctions to available pumps. 2.1.7 Unmanned barges and pontoons may have portable bilge pumping equipment only, arranged with their own power supply. For barges and pontoons for unlimited service such equipment shall be permanently installed. For barges and pontoons for restricted service the rules are based on the assumption that suitable bilge pumping equipment is available on board the barge or on board the towing/pushing vessel. This assumption will be included in the appendix to the class certificate to be issued for the barge.

2.2 Hatches and deck openings 2.2.1 Deck openings in barges and pontoons shall normally have hatch coamings and covers as given in Pt.3 2 Ch.12. Minimum design pressure for hatch covers in dry cargo barges is 3.5 kN/m . 2.2.2 The closing arrangement of deck openings for barges and pontoons with restricted service and high freeboard will be specially considered.

2.3 Bow height 2.3.1 The requirement for minimum bow height given in Pt.3 Ch.2 Sec.2 [2] may be dispensed with. Guidance note: For manned barges and pontoons the requirements for bow height should be clarified with the respective flag administration. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 28

Part 5 Chapter 11 Section 5

2.1.6 Unmanned barges and pontoons shall be provided with drainage facilities for compartments rooms mentioned in [2.1.1].

1 Materials 1.1 General requirements 1.1.1 A barge may be constructed using the following materials: steel reinforcement, FRP reinforcing rods, LWA concrete, NW concrete, structural grout, or fibre reinforced grout. 1.1.2 Concrete is in this standard used as a common reference to NW concrete, LWA concrete, structural grout, fibre reinforced structural grout and fibre reinforced structural concrete if the above specified materials are not included specifically. 1.1.3 Definitions (for further definitions, see DNV-OS-C502 Sec.4): — — — — —

NW denotes normal weight concrete LWA concrete denotes lightweight aggregate concrete fibre reinforced concrete is concrete mixed with either steel or FRP fibres fibre reinforced structural grout is grout mixed with either steel or FRP fibre FRP fibres are fibres cut from fibre reinforced polymers.

1.1.4 The material to be used in a concrete barge shall be in accordance with the requirements specified in DNV-OS-C502 Sec.4. 1.1.5 Testing of concrete, grout, steel, FRP, additions, admixtures and constituent materials shall all be in accordance with the requirements of DNV-OS-C502 Sec.4 M. 1.1.6 The material properties of concrete (with and without fibres) shall be in accordance with the requirement DNV-OS-C502 Sec.4 C and DNV-OS-C502 Sec.4 D. 1.1.7 The material properties of grout (with and without fibres) shall be in accordance with the requirement DNV-OS-C502 Sec.4 C, DNV-OS-C502 Sec.4 E and DNV-OS-C502 Sec.4 F. 1.1.8 For concrete, fibre reinforced concrete, structural grout and fibre and reinforced structural grout; the th 28 days characteristic compressive strength, fck , is defined as the lower 5 percentile found from statistical analysis of tests on cylindrical specimens with diameter 150 mm and height 300 mm. 1.1.9 For NW concrete, LWA concrete and fibre reinforced concrete; normalized compressive and tensile strength are required in detailed designed of structural members. Normalized values are given in DNV-OSC502 Sec.4. 1.1.10 For LWA concrete, grout, fibre reinforced concrete and fibre reinforce grout; MC material certificates are required, documenting specific product properties. For further details, see DNV-OS-C502 Sec.4. 1.1.11 For FRP reinforcement MC material certificates are required, documenting specific product properties. For further details, see DNV-OS-C502 Sec.4. 1.1.12 MC material certificates for NW Concrete, reinforcement and tendons as required by DNV-OS-C502 Sec.4 shall be submitted. 1.1.13 For fatigue properties of concrete, LWA concrete, fibre reinforced concrete, grout and fibre reinforced grout; references are made to DNV-OS-C502 Sec.6 M200. Parameters defining the fatigue parameters shall be defined in the material certificates.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 29

Part 5 Chapter 11 Section 6

SECTION 6 CONCRETE HULL (TENTATIVE RULES)

1.1.15 Anchorage devices and mechanical splices shall be documented by product certificates, see DNV-OSC502 Sec.4 G200. 1.1.16 Friction welded end anchorages on rebars (T-heads) shall be qualified tested in advance with the actual type of rebar and be routinely tested during production. The test program shall include a tension test and a bend test to document strength and ductility of the connection. The friction weld shall not fail before the rebar. 1.1.17 Welding procedures, together with the extent of testing for weld connections relevant to reinforced concrete and concrete structures, shall be specified and approved in each case. 1.1.18 The concrete material and steel material shall be documented in accordance with DNV-OS-C502 Sec.4 A100.

2 Design principles 2.1 General requirements 2.1.1 The design shall be performed according to the load and resistance factor design format (LRFD method) as detailed in DNV-OS-C502 Sec.6. The design shall be carried out for the limit states of strength (ULS), accident (ALS), fatigue (FLS) and serviceability (SLS). 2.1.2 Detailed design for structural capacity, water tightness (SLS), Fatigue life and Progressive collapse shall be carried out in accordance with DNV-OS-C502 Sec.6. 2.1.3 The applied loads (ULS and SLS) on a concrete barge as defined in [3.1] and [3.2] are based on rules for classification: SHIP Pt.3 combined with partial load factors as given in DNV-OS-C502 Sec.5 D. 2.1.4 Relevant accidental conditions (ALS) shall be included in the design, see DNV-OS-C502 Sec.5 C400. Accidental loads, including collision loads, shall not be less than in accordance with DNV-OS-A101 D. 2.1.5 Fatigue life (FLS) shall be carried out as given in DNV-OS-C502 Sec.6 M with minimum design life 20 years. Guidance note: The fatigue life may be calculated applying a long term distribution based on ULS loads, excluding partial load factors, of 20 years 8

(10 cycles), assuming a Weibull shape parameter 1.0. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.6 Response from hull girder loads and local pressures shall be combined in accordance with DNV-OSC502 Sec.5 D. 2.1.7 In order to document transverse strength, the design shall be performed applying transverse hull girder loads in combination with local loads. The vertical wave bending moments in transverse direction may be based on [3.2.2], exchanging L with B, and applying kwm = 1.0 between port and starboard side. The vertical wave shear forces in transverse direction may be based on [3.2.3], applying kwqp(n) = 0.7 between port and starboard side. 2.1.8 For barges with restricted service, CW and CWO applied in order to establish hull girder loads ([3.2]) and local loads ([3.1]) may be reduced as given in Table 1.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 30

Part 5 Chapter 11 Section 6

1.1.14 MC material certificates for NW Concrete, reinforcement and tendons as required by DNV-OS-C502 Sec.4 shall be submitted.

Guidance note: 2

The wave load analysis should be carried out applying all headings and with Cos wave spreading profile. In order to document transverse strength, it is expected that beam sea with wave length approximately equal to the breadth of the barge will be will be dimensioning. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3 Loads 3.1 Local loads 3.1.1 The design sea pressure acting on side, bottom and weather deck shall be taken as the sum of the 2 static and the dynamic pressure in kN/m as: — For load point below summer load waterline: Psea = 10 h0

f, G, Q

+ kseaPW

f, E

— For load point above summer load waterline: Psea = kseaPW

f, E

where:

ksea

= factor depending on limit state = 0.5 for SLS = 1.0 for ULS

γf, G, Q γf, E PW

= partial load factor for permanent and functional loads as given in DNV-OS-C502 Sec.5 D = partial load factor for environmental loads as given in DNV-OS-C502 Sec.5 D 2

= dynamic sea pressure, in kN/m , as given in Pt.3 Ch.4 2

3.1.2 All tanks shall be designed for the following internal design pressure in kN/m : P

AV

=

ρghs

f, G, Q

+ kaVρaZ

f, E

where:

kaV

= factor depending on limit state = 0.5 for SLS = 1.0 for ULS

hs aZ

= vertical distance in m from the load point to the top of tank, excluding smaller hatchways = vertical acceleration as given in Pt.3 Ch.4 Sec.3 [3.2.3], taken in centre of gravity of tank.

3.1.3 For tanks where the air pipe may be filled during filling operations, the following additional internal 2 design pressure in kN/m shall be considered: P

d

= (ρ ghs + Pdrop-2)

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

f, G, Q

Page 31

Part 5 Chapter 11 Section 6

2.1.9 For barges intended to operate in a specific area, the wave induced hull girder loads, sea pressures and accelerations may be based on wave load analysis applying site specific scatter diagram with minimum 20 years return period. This limitation will then be stated in the appendix to the classification certificate.

Pdrop-2

2

= calculated pressure drop, in kN/m , as further described in Pt.3 Ch.4 Sec.6

Guidance note: This internal pressure needs not to be combined with extreme environmental loads. Normally only static global response need to be considered. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e--2

3.1.4 The weather deck shall be designed for the following design pressure in kN/m : P

dk

= q(g

f, G, Q

+ kaVaZ-env

f, E)

where: 2

q aZ-env

= deck loading in t/m . q shall not be taken less than 0.7 T 2

= vertical envelope acceleration, in m/s , as defined in Pt.3 Ch.4 Sec.3 [3.3.3] for the location considered.

3.1.5 For concrete barges with L>100 m, the bottom forward shall be strengthened against slamming, 2 applying the following impact pressure in kN/m : P

slam

= PSL

f, E

where:

PSL

= design slamming pressure as given in Pt.3 Ch.10 Sec.2. The ballast draught TF may be substituted by full draught TSC. Guidance note: This impact pressure is only to be considered for the ULS case and needs not to be combined with extreme environmental loads. Normally only static global response need to be considered. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.6 The forces in kN from cargo, equipment or other components acting on supporting structures shall be taken as: P

Vd

= (g

f, G, Q

+ kaVaZ-env γf, E) M

P

Hd

= (g

f, G, Q

+ kaTaY-env γf, E) M

where:

kaT

= factor depending on limit state = 0.67 for SLS = 1.0 for ULS

kaV aY-env

= as given in [3.1.2]

aZ-env

= vertical envelope acceleration, in m/s , as given in Pt.3 Ch.4 Sec.3 [3.3.3] for the location considered

M

= mass of cargo, equipment or other components in t

2

= transverse envelope acceleration, in m/s , as defined in Pt.3 Ch.4 Sec.3 [3.3.2] for the location considered 2

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 32

Part 5 Chapter 11 Section 6

where:

= vertical design force in kN = horizontal design force in kN.

3.2 Hull girder loads 3.2.1 The design stillwater bending moments, Msw, and design stillwater shear forces, Qsw, shall be based on the envelope curves representing all relevant loading conditions specified in the trim and stability booklet, and shall be combined with partial load factor for permanent loads as given in DNV-OS-C502 Sec.5 D. 3.2.2 The vertical wave bending moments in kNm at arbitrary positions along the length of the barge are normally not to be taken less than: MWave = kglobalMWV

f, E

where:

kglobal

= factor depending on limit state = 0.59 for SLS = 1.0 for ULS

γf, E MWV

= partial load factor for environmental loads as given in DNV-OS-C502 Sec.5 D = rule-defined vertical wave bending moments as given in Pt.3 Ch.4 Sec.4

3.2.3 The vertical wave shear forces in kN at arbitrary positions along the length of the barge are normally not to be taken less than: QWave = kglobalQWV

f, E

where:

kglobal, γf, E = as given in [3.2.2] = rule-defined vertical wave shear forces, in kN, as given in Pt.3 Ch.4 Sec.4 QWV

4 Design resistance 4.1 General requirements 4.1.1 The characteristic resistance of a cross-section or a structural member shall be derived from characteristic values of material properties and nominal geometrical dimensions. The design resistance shall be determined in accordance with the approach outlined in DNV-OS-C502 Sec.6. 4.1.2 The design shall document adequate strength and tightness in all design situations. The necessary limitation in concrete stresses, reinforcement stress and crack width to ensure water tightness is provided in DNV-OS-C502 Sec.6 O600. 4.1.3 DNV-OS-C502 Sec.6 B contains detailed information on the different limit states, characteristic values for material strength to be used in design, partial safety factors for material, and design by testing as a special case. 4.1.4 DNV-OS-C502 Sec.6 C specifies design material strength, material coefficients, stress-strain curves, temperature effects and creep.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 33

Part 5 Chapter 11 Section 6

PVd PHd

4.1.6 Provisions for design of slender members are given in DNV-OS-C502 Sec.6 E. 4.1.7 Provisions for predicting the shear capacity of hull and plates are provided in DNV-OS-C502 Sec.6 F. 4.1.8 Provisions for predicting the combined bending, shear and torsion capacity are provided in DNV-OSC502 Sec.6 G. 4.1.9 DNV-OS-C502 Sec.6 H provides a general method for predicting the shear strength of structural members subjected to in-plane shear forces. 4.1.10 DNV-OS-C502 Sec.6 J provides requirements for shear strength of construction joints. 4.1.11 DNV-OS-C502 Sec.6 K provides requirement for design of bond strength and anchorage strength of reinforcement bars. 4.1.12 DNV-OS-C502 Sec.6 L provides requirements for design of partly loaded areas in ULS. 4.1.13 The fatigue strength shall be designed and evaluated in accordance with the provisions of DNV-OSC502 Sec.6 M. 4.1.14 The strength in accidental limit state shall be predicted based on DNV-OS-C502 Sec.6 N. 4.1.15 Durability, cracking, tightness and deflections are controlled by SLS. The SLS requirements are provided in DNV-OS-C502 Sec.6 O. 4.1.16 Requirements for design by testing are provided in DNV-OS-C502 Sect.6 P. 4.1.17 Placing and detailing of the reinforcement are both important for the hull durability. Provisions for detailing including requirements for minimum amount of reinforcement in the concrete section are provided in DNV-OS-C502 Sec.6 Q. For concrete barges, the minimum concrete cover to reinforcement may be reduced to 25 mm, provided the concrete is covered with an elastic epoxy-based coating. 4.1.18 Provisions for designing concrete members with fibre reinforcement are provided in DNV-OS-C502 Sec.6 S. 4.1.19 Provisions for the design of structural members in which concrete is replaced by structural grout are given in DNV-OS-C502 Sec.6 T. 4.1.20 Provisions for the design of structural members in which concrete is replaced by fibre reinforced structural grout are given in DNV-OS-C502 Sec.6 U. 4.1.21 For design of a composite steel-concrete hull, provisions are given in DNV-OS-C502 Sec.6 A500. When designing for composite action between concrete and steel plating, then sufficient number of studs shall be provided.

5 Survey and testing 5.1 Survey and testing during newbuilding of concrete barges 5.1.1 The construction of the concrete barge shall be planned and executed in accordance with the provisions of DNV-OS-C502 Sec.7.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 34

Part 5 Chapter 11 Section 6

4.1.5 Calculation approach for prediction of bending moment capacity is provided in DNV-OS-C502 Sec.6 D.

5.1.3 The requirements given in DNV-OS-C502 Sec.7 with respect to construction documentation, quality control, construction planning, materials, material certificates, material testing, formwork, tolerances, precast concrete elements, reinforcement, production of concrete and grout, transport, compaction and curing of concrete, repairs, corrosion protection, site records and as built documentation shall be complied with, as found relevant. 5.1.4 The Society will as part of classification, review site records and review on-going activities to ensure that the construction is in accordance with design intent.

5.2 Survey and testing after delivery of concrete barges 5.2.1 For hull and equipment, concrete barges are in general to follow the survey intervals and extent as given in Pt.7 Ch.1 Sec.2 [2] for annual surveys, Pt.7 Ch.1 Sec.3 [2] for intermediate surveys, and Pt.7 Ch.1 Sec.4 [2] for renewal surveys. 5.2.2 The requirements for dry-docking as given in Pt.7 Ch.1 Sec.5 [1.1.3] may be dispensed from, provided the bottom survey is carried out afloat according to the requirements for the class notation BIS. This will then be stated in the appendix to the class certificate. 5.2.3 In addition to the survey extent given in [5.2.1], the concrete barge is subject to an in-service inspection scheme. This scheme shall be further specified in an in-service inspection manual as part of as built documentation, and shall be harmonized with the periodic survey intervals given in [5.2.1] as far as possible. 5.2.4 The objective of the in-service inspection is described in DNV-OS-C502 Sec.8. The overall objective for the inspection program is to ensure that the barge is suitable for its intended purpose throughout its lifetime. 5.2.5 The scope of the in-service inspection is described in DNV-OS-C502 Sec.8. An in-service inspection programme shall be prepared as part of the design process considering safety, environmental consequences and total life cycle costs. 5.2.6 In preparing the inspection programme, special attention shall be paid on observing deterioration mechanisms for the relevant materials and structural components. 5.2.7 The inspection and monitoring types relevant for the concrete hull is defined in DNV-OS-C502 Sec.8 A1000. 5.2.8 If protective coating is applied in accordance with [5.1.3], the coating shall be maintained throughout the working life of the barge.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 35

Part 5 Chapter 11 Section 6

5.1.2 A quality management system based on the requirement of EN ISO 9001 or equivalent shall be applied during construction of the barge.

July 2016 edition

Main changes July 2016, entering into force as from date of publication • Sec.2 Hull — Sec.2 [4.2]: Replaced blowing out pressure with air overpressure for a more consistent use of terms. The air overpressure is applicable for a static load scenario since emptying tanks in extreme sea condition will not be applicable. — Sec.2 [5.1.1]: Some minor change to the application is included. — Sec.2 [5.1.2] : For the minimum section modulus requirement amidship which follows IACS gross scantlings apply instead of net scantlings. Correction factor related to service restriction was missed out in the January 2016 release and has now been implemented. — Sec.2 [5.1.3]: Due to the change to gross section modulus in [5.1.2] the allowable stresses in [5.1.3] are amended accordingly.

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Amendments January 2016 • General — Only editorial corrections have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.11. Edition July 2017 Non self-propelled units

DNV GL AS

Page 36

Part 5 Chapter 11 Changes – historic

CHANGES – HISTORIC

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition July 2017

Part 5 Ship types Chapter 12 Fishing vessels

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS July 2017

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

This document supersedes the January 2017 edition of RU-SHIP Pt.5 Ch.12. Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour.

Changes July 2017, entering into force 1 January 2018 Topic

Reference

Description

Material requirements for fishing vessels with refrigerated cargo holds.

Sec.2 [2.6]

Paragraph inserted requiring structural members of the refrigerated cargo holds and other refrigerated compartments in fishing vessels to follow the material requirements for RM notation.

Electrical equipment in fish processing decks/ spaces with ammonia refrigerant systems.

Sec.3 [4.3.3]

Removed requirement for de-energizing non-ex protected electrical equipment at 5000 ppm level.

Sec.3 [4.3.4]

Removed general requirement for electrical equipment to be ex-certified or arranged for automatic de-energizing.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 3

Part 5 Chapter 12 Changes - current

CHANGES – CURRENT

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................... 7 1 Introduction.........................................................................................7 1.1 Introduction..................................................................................... 7 1.2 Scope..............................................................................................7 1.3 Application....................................................................................... 7 2 Class notations.................................................................................... 8 2.1 Ship type notations.......................................................................... 8 2.2 Additional notations.......................................................................... 8 3 Documentation.....................................................................................9 3.1 Documentation requirements............................................................. 9 3.2 Additional stability requirements....................................................... 10 4 Testing............................................................................................... 10 4.1 Testing during newbuilding...............................................................10 5 International regulations................................................................... 10 5.1 General requirements...................................................................... 10 Section 2 Hull........................................................................................................ 11 1 Hull arrangement...............................................................................11 1.1 Arrangement on deck...................................................................... 11 1.2 Forecastle...................................................................................... 11 1.3 Refrigerated sea water tanks for fish.................................................11 2 Design requirements..........................................................................12 2.1 General requirement....................................................................... 12 2.2 Draught for scantlings..................................................................... 12 2.3 Cargo hold bulkheads......................................................................12 2.4 Pillars............................................................................................ 13 2.5 Bulwarks........................................................................................ 13 2.6 Refrigerated cargo holds................................................................ 13 3 Local scantlings for notation fishing vessel....................................... 13 3.1 Additional requirements................................................................... 13 4 Local scantlings for notation stern trawler........................................ 13 4.1 Additional requirements................................................................... 13 5 Cargo holds for fish in bulk - bulkhead arrangement and strength..... 14 5.1 General requirements...................................................................... 14 5.2 Location of bulkheads......................................................................14

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 4

Part 5 Chapter 12 Contents

CONTENTS

5.4 Longitudinal bulkheads with vertical wooden boards............................ 14 5.5 Longitudinal bulkheads with horizontal wooden boards.........................16 5.6 Transverse bulkheads with vertical wooden boards.............................. 17 5.7 Transverse bulkheads with horizontal wooden boards.......................... 18 5.8 Permanent steel bulkheads.............................................................. 19 5.9 Removable bulkheads of steel or aluminium....................................... 20 5.10 Corrugated aluminium sections....................................................... 21 Section 3 Systems and equipment........................................................................ 23 1 Bilge and drainage arrangement....................................................... 23 1.1 Cargo holds for fish in bulk..............................................................23 1.2 Tanks for fish in refrigerated sea water tanks (RSW-tanks)................... 23 1.3 Tween deck for fish in bulk.............................................................. 24 1.4 Engine room bilge water monitoring..................................................24 2 Prevention of tween deck flooding.................................................... 24 2.1 Arrangement of side openings leading to tween deck (working deck)......24 2.2 Drainage of tween deck with openings in side.................................... 25 2.3 Arrangement of openings from tween deck to other spaces.................. 26 3 Enclosed tween deck......................................................................... 26 3.1 Enclosed tween deck where water is used in processing....................... 26 4 Spaces with refrigeration installations of direct expansion type........ 26 4.1 Refrigeration plant.......................................................................... 26 4.2 Refrigerated holds for stowage of frozen fish/fish products................... 26 4.3 Fish processing decks/spaces........................................................... 27 Section 4 Fire safety and lifesaving appliances.....................................................29 1 Design requirements..........................................................................29 1.1 Internal communications..................................................................29 2 Fire safety..........................................................................................29 2.1 Application..................................................................................... 29 2.2 Fire pumps and water distribution system..........................................29 2.3 Fire safety arrangement in machinery spaces..................................... 29 2.4 Fire-fighter’s outfits.........................................................................30 2.5 Fire protection of bulkheads and decks..............................................30 2.6 Portable fire extinguishers................................................................30 2.7 Fire control plan............................................................................. 30 Section 5 Electrical systems..................................................................................31 1 Electrical power generation and distribution..................................... 31

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 5

Part 5 Chapter 12 Contents

5.3 Design load conditions.....................................................................14

Section 6 Stability and load line........................................................................... 32 1 Stability............................................................................................. 32 1.1 Application..................................................................................... 32 1.2 Stability criteria.............................................................................. 32 1.3 Loading conditions.......................................................................... 33 1.4 Ice consideration............................................................................ 33 1.5 Roll reduction tanks........................................................................ 34 1.6 Water on deck and in compartments temporarily open to sea............... 34 1.7 Onboard cranes.............................................................................. 35 1.8 Forces from fishing gear.................................................................. 35 1.9 Stability for vessels with qualifier N.................................................. 35 2 Load line............................................................................................ 35 2.1 Freeboard...................................................................................... 35 2.2 Openings and closing appliances.......................................................36 2.3 Signboards..................................................................................... 39 2.4 Bow height for vessels with qualifier N..............................................39 Changes – historic................................................................................................ 40

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 6

Part 5 Chapter 12 Contents

1.1 General..........................................................................................31

Symbols For symbols and definitions not defined in this chapter, refer to Pt.3 Ch.1 Sec.4.

Loa

= length overall, in m, taken as the maximum length of the vessel measured parallel to the waterline.

1 Introduction 1.1 Introduction These rules provide requirements for vessels intended for fishing.

1.2 Scope The rules in this chapter give requirements for hull strength, systems and equipment, safety and availability, stability and load line and the relevant procedural requirements applicable to fishing vessels.

1.3 Application 1.3.1 The requirements in this chapter are supplementary to those in Pt.2, Pt.3 and Pt.4 applicable for the assignment of main class. 1.3.2 Vessels built in compliance with the relevant requirements in this chapter may be assigned one of the following class notations: — Fishing vessel (see Sec.2 [3]) — Stern trawler (see Sec.2 [4]). 1.3.3 Vessels with arrangement in cargo holds for fish in bulk in compliance with the requirements given in Sec.2 [5] may have the qualifier S added to the class notation given in [1.3.2]. 1.3.4 Vessels which satisfy the additional requirements in Sec.6 [1.9] and Sec.6 [2.4] (Norwegian Maritime Authority requirements) may have the qualifier N added to the class notation given in [1.3.2] and [1.3.3]. 1.3.5 Vessels with fish processing spaces/decks and refrigerated holds for frozen fish products may have the class notation RM added if the refrigeration plant satisfies the requirements given in Pt.6 Ch.4 Sec.10.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 7

Part 5 Chapter 12 Section 1

SECTION 1 GENERAL

2.1 Ship type notations Vessels built in compliance with the requirements as specified in Table 1 will be assigned the class notations as follows: Table 1 Ship type notations

Class notation

Description

Qualifier

Additional description

Design requirements, rule reference

<none>

Fishing vessel

Arranged for fishing as main purpose

S

Arranged for carriage of fish in bulk, with shifting boards in cargo holds

N

Ship also complying with the requirements of the Norwegian Maritime Directorate (NMD)

<none>

Stern trawler

Arranged for fishing as main purpose

S

Arranged for carriage of fish in bulk, with shifting boards in cargo holds

N

Ship also complying with the requirements of the Norwegian Maritime Directorate (NMD)

Sec.1 to Sec.6

2.2 Additional notations The following additional notations, as specified in Table 2, are typically also applied to vessels intended for fishing: Table 2 Additional notations Class notation

Description

Application

TMON

Tailshaft condition monitoring arrangement

All ships

BIS

Ships built for in-water survey of the ship's bottom and related items

All ships

Clean

Requirements for controlling and limiting operational emissions and discharges

All ships

RM (X°C/Y°C sea)

Equipped with a refrigeration plant where the lowest chamber temperature X is given in °C and maximum sea water temperature Y in °C

All ships

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 8

Part 5 Chapter 12 Section 1

2 Class notations

3.1 Documentation requirements 3.1.1 General For general requirements to documentation, including definition of the info codes, see Pt.1 Ch.3 Sec.2. For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3. 3.1.2 General Documentation shall be submitted as required by Table 3. Table 3 Documentation requirements Object

Structural fire protection

Fire water system

Machinery spaces fixed fire fighting system Fire detection and alarm system

Documentation type

Additional description

Info

G060 - Structural fire protection drawing

AP

G061 - Penetration drawings

AP

S010 - Piping diagram (PD)

AP

S030 - Capacity

AP

Z030 - System arrangement plan

AP

G200 - Fixed fire extinguishing system documentation

AP

I200 - Control and monitoring system documentation

If E0 notation is requested

AP

Z030 - System arrangement plan

If E0 notation is requested

AP

Safety, general

G040 - Fire control plan

AP

Decks

Z030 - Arrangement plan

Including all fishing equipment (winches, cranes, etc.), doors, hatches, working areas, etc.

FI

Trawl gallow structure

H050 - Structural drawing

Including hull support, load cases and respective forces

AP

Winch supporting structures

H050 - Structural drawing

Including design loads, wire loads, footprint loads and shear stoppers

AP

Crane supporting structures

H050 - Structural drawing

Including design loads and reaction forces

AP

Bilge water control and monitoring system

I200 - Control and monitoring system documentation

Control of valves and pumps

AP

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 9

Part 5 Chapter 12 Section 1

3 Documentation

3.2.1 Stability information in a simplified form may be accepted as an alternative or supplement to the stability booklet. Guidance note: A diagram showing the necessary amount of cargo in hold to comply with the criteria as a function of the percentage of fuel remaining, may be used as simplified stability information. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

3.2.2 Operational information shall be given such as general precautions against capsizing and procedures related to severe weather conditions, including precautions to prevent unintentional flooding. This should also include information on safe use of cranes and fishing gear, if relevant. 3.2.3 A drawing of buoyant volumes with their openings and closing appliances shall be included. This drawing shall include instructions on operation of the closing appliances, e.g. to be kept closed at sea. 3.2.4 If any of the closing appliances referred to in Sec.6 [1.2.3] shall be left open periodically during fishing, the opening(s) shall be considered as flooding points in the stability calculations. If the angle of flooding is less than 30°, Sec.6 [1.6.2] applies. Guidance note: The internal opening of garbage chute which is operated in such a way that only one of the two required closing devices is open at a time need not be considered as a flooding point. (See Sec.3 [2.1.5] for arrangement of garbage chutes.) ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

4 Testing 4.1 Testing during newbuilding Testing of insulation materials being part of fire protection of bulkheads and decks shall be carried out in accordance with a recognized standard, e.g. DIN 4102.1 B2 or equivalent. The test method chosen shall be suitable for the type of foam in question.

5 International regulations 5.1 General requirements The following international regulations may apply: — Torremolinos International Convention for the Safety of Fishing Vessels, 1977, amended by Protocol of 1993 as applied by the relevant Flag State Administration for fishing vessels with a length L larger than 45 m (did not enter into force on an international basis). — European Communities, Commission Directive 1997/70/EC of 11 December 1997 as amended by Commission Directive 2002/35/EC of 25 April 2002 for fishing vessels with a length L larger than 24 m. — Code on Intact Stability for All Types of Ships Covered by IMO Instruments, Resolution A.749(18), as amended. — Code for Safety of Fishermen and Fishing Vessels, 2005 IMO. — Voluntary Guidelines for the Design, Construction and Equipment of Small Fishing Vessels, 2005 FAO/ILO/ IMO .

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 10

Part 5 Chapter 12 Section 1

3.2 Additional stability requirements

1 Hull arrangement 1.1 Arrangement on deck 1.1.1 Masts, rigging, superstructures, deckhouses and other items on deck on vessels intended for service in Arctic waters shall be so designed and arranged that excessive accumulation of ice is avoided. The rigging shall be kept at a minimum, and the surfaces of superstructures and other erections shall be as even as possible and free from projections and irregularities 1.1.2 Air pipes from fuel oil tanks shall extend to a deck above freeboard deck or otherwise be protected to prevent seawater from entering the tanks. Guidance note: The term be protected is meant as arrangement utilising common venting through an overflow tank, or a drain pot in the air pipe with automatic drainage to a suitable tank. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

1.2 Forecastle 1.2.1 Fishing vessels shall have a forecastle if the sheer in the forebody is less than 1.5 times standard sheer according to the International Convention on Load Lines, 1966. 1.2.2 The length of the forecastle shall not be less than 0.07 LLL m, and the mean height shall not be less than 1.5 m. 1.2.3 The forecastle shall be closed. When the length of the forecastle is greater than 0.07 LLL, the surplus part may be open if fitted with freeing ports according to the International Convention on Load Lines, 1966. 1.2.4 The required bow height is defined as the vertical distance at the forward perpendicular from the loaded waterline to the top of the exposed deck at side and given by:

where:

CB-LL

= block coefficient at loaded waterline or 0.5 if CB-LL is not known.

1.3 Refrigerated sea water tanks for fish 1.3.1 Refrigerated sea water (RSW) tanks for transportation of fish shall be designed for relevant pressure heads in accordance with the rules.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 11

Part 5 Chapter 12 Section 2

SECTION 2 HULL

where:

tgr

= skin gross thickness, in mm, not to be less than 5 mm.

1.3.3 The strength of the lining plate shall satisfy: 1) 2)

the requirement to local strength of bulkhead plate as given in Pt.3 Ch.6 Sec.4 [1] (hull girder longitudinal stress need not to be included), or the space between the lining and the bulkhead plate is filled with a foam with sufficient strength and stiffness to carry the lining plate without permanent set. The actual design tank pressure shall be used as strength criteria for the foam. The yard has the responsibility for appropriate selection and application of the foam.

1.3.4 The insulation material shall have good adhesion to steel and suitable strength characteristics, e.g. polyurethane foam. The steel surface shall be corrosion protected before it is insulated. 1.3.5 Corrugated bulkheads shall be supported along both bulkhead flanges in the bottom structure with sufficient connections to crossing members. Carlings shall be fitted in way of corners in corrugations and ends of unstiffened plate panels. At lower end of the corrugated bulkheads, brackets aligned with the corrugation webs shall be arranged underneath.

2 Design requirements 2.1 General requirement 2.1.1 The wall thickness of the steel plates between hull plating and closeable non-return valve shall not be less than 12.5 mm. However, if possible to get access for inspection and maintenance the thickness can be reduced to 10 mm.

2.2 Draught for scantlings 2.2.1 For fishing vessels for which the draught is not limited by any freeboard mark, the moulded depth D instead of draught T shall be used when calculating the scantlings of strength members.

2.3 Cargo hold bulkheads 2.3.1 The cargo hold bulkheads may be classified as follows: Type A: Bulkheads in cargo holds intended for dry cargo. Type B: Bulkheads in cargo holds intended for fish in bulk. Type C: Bulkheads in cargo holds intended for liquids (for instance RSW-tanks, sludge etc.).

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 12

Part 5 Chapter 12 Section 2

1.3.2 Where an internal skin is fitted and the gap between skin and hull structure is filled with insulation of an approved type, this skin shall be welded continuously to every other frame/stiffener and slot-welded to the intermediate one. The skin plate shall be made continuous with good end connections and should not be terminated abruptly. An effective flange width in mm, may be included when calculating the section modulus of strength members:

For type A: Pt.3 Ch.6 - Watertight bulkheads. For type B: [5]. For type C: Pt.3 Ch.6 - Tank bulkheads.

2.4 Pillars 2.4.1 Pillars acting as supports for deck loadings shall be permanently connected at top or bottom. If the connections are arranged with bolts these bolts shall be secured by welding. 2.4.2 Pillars acting as supports for shifting boards only may have ordinary bolt connections.

2.5 Bulwarks 2.5.1 The thickness of bulwark plating shall not be less than 80% of rule thickness of side shell plating, and minimum 6 mm. 2.5.2 Bulwark stays shall be fitted at every second frame.

2.6 Refrigerated cargo holds 2.6.1 The structural members for the refrigerated cargo holds, bait holds and other refrigerated compartments related to the cargo processing shall follow the material requirements for RM notation given in Pt.6 Ch.4 Sec.10.

3 Local scantlings for notation fishing vessel 3.1 Additional requirements 3.1.1 The net thickness, in mm, of bottom and side shell plating up to a height 2 m above loaded waterline shall not be less than:

4 Local scantlings for notation stern trawler 4.1 Additional requirements 4.1.1 The net thickness, in mm, of bottom and side shell plating up to a height 2 m above loaded waterline shall not be less than:

4.1.2 The net thickness, in mm, of trawl ramp and adjacent side plating, stern and side plating abaft the point where the trawling boards are normally taken on board, shall not be less than:

4.1.3 Between trawl gallows the bulwark plating shall have the same thickness as the side shell plating, and bulwark stays shall be fitted at every frame.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 13

Part 5 Chapter 12 Section 2

2.3.2 The strength of the different bulkhead types shall comply with the requirements given in:

3

4.1.5 The gross section modulus, in cm , of stiffeners in the trawl ramp shall not be less than:

5 Cargo holds for fish in bulk - bulkhead arrangement and strength 5.1 General requirements 5.1.1 Assumptions The rules in this section are based on the assumptions that: — during loading in vessels having one longitudinal bulkhead, the level of cargo at any time will be approximately the same on both sides of the bulkhead — cargo not carried in tanks, is drained before loading — cargo holds fully loaded with fish treated with preserving agent, are checked regarding swelling.

5.2 Location of bulkheads 5.2.1 Longitudinal watertight bulkheads are normally to be arranged as follows: B ≤ 6 m: One centre line bulkhead. B > 6 m: Two bulkheads. 5.2.2 Longitudinal bulkheads shall be positioned symmetrically about the ship's centre line. 5.2.3 Transverse bulkheads in cargo holds are normally not to be spaced more than 0.15 L apart. The spacing need not be taken less than 9 m and is not to exceed 12 m.

5.3 Design load conditions 5.3.1 If there is one longitudinal centre line bulkhead a loading condition as defined in [5.1.1] is assumed. 5.3.2 If there are two or more longitudinal bulkheads, these shall be designed for one-sided loading. 5.3.3 Transverse bulkheads shall be designed for one-sided loading.

5.4 Longitudinal bulkheads with vertical wooden boards 5.4.1 In hatch openings in which vertical wooden boards are used, a steel stiffener shall be fitted at each side of the bulkhead top, and if necessary also half way up the bulkhead. The gross section modulus of the longitudinal stiffeners in accordance with [5.4.2] is given on the assumption that stiffeners on each side of the bulkhead are connected to each other at 1/4 and 1/2 span. For area of connection, see [5.7.9]. If the stiffeners are not connected to each other, the section modulus according to [5.4.2] is doubled.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 14

Part 5 Chapter 12 Section 2

4.1.4 Where bulwarks, sheer strake, side shell and transom plating are particularly exposed to blows and chafing, steel rubbing pieces shall be fitted, consisting of minimum 75 × 37 mm half-round bars or equivalent.

where:

b b h ℓ s

= 1.2 for one longitudinal bulkhead = 1.6 for two or more longitudinal bulkheads = height of bulkhead, in m = distance between supports of steel stiffeners, in m = greatest transverse distance between bulkheads or between bulkhead and ceiling at side, in m.

5.4.3 When steel stiffeners are fitted at both the top and half height of the bulkhead, the gross section 3 modulus, in cm , of the steel stiffeners shall not be less than: Upper stiffeners:

Middle stiffener:

where:

b b

= 1.6 for one longitudinal bulkhead = 2.2 for two or more longitudinal bulkheads.

Remaining symbols as given in [5.4.2]. 5.4.4 When there is one longitudinal bulkhead, the wooden board thickness, in mm, shall not be less than: — Without steel stiffener at mid-height: — With steel stiffener at mid-height and at bulkhead top: where:

h

= bulkhead height, in m.

When there are two or more longitudinal bulkheads, the thickness, in mm, of wooden boards shall not be less than:

where:

ℓ h

= greatest span between supports, in m = bulkhead height, in m.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 15

Part 5 Chapter 12 Section 2

3

5.4.2 The gross section modulus, in cm , of each steel stiffener shall not be less than:

where:

ℓ h

= greatest span between supports, in m = bulkhead height, in m.

5.4.6 In hatch openings a channel section or similar shall be fitted over the top of the bulkhead to prevent the boards from floating away from the bulkhead. If the channel section is supported by the hatchway beams, these shall be secured to the hatch coamings. 5.4.7 The depth of guides for vertical boards shall be at least 100 mm below the deck and at the bottom. The minimum thickness of the section or plate which forms the guide shall be 10 mm. The clearance in the longitudinal direction of the boards shall be as small as possible. 5.4.8 Guide bars shall have a continuous weld connection to the deck and bottom structure, see [5.7.4]. In way of hatches the bottom guides shall be stiffened with tripping brackets maximum two (2) frame spaces apart. Guide bars bedded in concrete shall be fastened to the ship's bottom structure. If this is not feasible, the guide bars shall be securely fastened in the concrete.

5.5 Longitudinal bulkheads with horizontal wooden boards 5.5.1 The distance between vertical uprights, i.e. steel supporting beams, or permanent transverse bulkheads and uprights is normally not to be greater than 2.0 m and is in no case to exceed 2.25 m. 3

5.5.2 If there is one longitudinal bulkhead, the gross section modulus, in cm , of uprights shall not be less than:

where:

h b s

= free span of upright, in m = distance between uprights, in m = greatest transverse distance between bulkheads or between bulkhead and ceiling at side, in m. 3

5.5.3 If there are two or more longitudinal bulkheads, the gross section modulus, in cm , of uprights shall not be less than:

where:

h b

= free span of upright, in m = distance between uprights, in m.

5.5.4 The uprights shall be secured at top and bottom so that the reaction forces are distributed to adjacent structures.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 16

Part 5 Chapter 12 Section 2

5.4.5 When there are two or more longitudinal bulkheads, the thickness, in mm, of wooden boards shall not be less than:

5.5.6 Permanent pillars for hatch end beams or transverses which also serve as guides for shifting boards or removable bulkheads in steel ships shall have extra stiffening with brackets at the top. For scantlings of pillars, see [5.5.3] and [5.5.4]. 5.5.7 The wooden board gross thickness, in mm, shall not be less than:

where:

tmin tmin b b h ℓ

= 76 mm for h ≥ 1.9 m = 63 mm for h < 1.9 m = 20 for one longitudinal bulkhead = 24 for two or more longitudinal bulkheads = bulkhead height, in m = distance between uprights, in m.

5.5.8 Supporting guides for wooden boards in stiffeners or uprights shall be at least 75 mm deep and made of plates or sections of at least 10 mm thickness. If the sections do not comply with the requirements to groove depth or breadth for bulkhead boards, a flat bar (or similar) shall be welded to the flange of the section and the breadth may be adjusted by inserting a lining into the groove. 5.5.9 Bulkheads shall extend to the deck. Between beams, the spaces above bulkheads shall be packed with filling pieces such as steel plates which shall run down the side of the uppermost board and be fastened to this.

5.6 Transverse bulkheads with vertical wooden boards 5.6.1 When horizontal steel stiffeners are fitted at half height of the bulkhead, the gross section modulus, in 3 cm , of the steel stiffener shall not be less than:

where:

h ℓ

= bulkhead height, in m = distance between supports, in m.

5.6.2 In exceptional cases the horizontal stiffener may be fitted on the hold side. A 100 x 12 mm flat bar is then to be fitted on the other side of the bulkhead. The bar is bolted to the horizontal stiffener with bolts 2 spaced not more than 200 mm. The gross sectional area, in cm , of the bolts at bottom of threads shall not be less than:

where:

h

= bulkhead height, in m

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 17

Part 5 Chapter 12 Section 2

5.5.5 If openings are cut in the uprights for the entering of the upper boards, the boards in the opening shall be locked in position to prevent their slipping out of the guide.

= bolt spacing, in m.

Minimum bolt diameter is 16 mm. 5.6.3 The horizontal stiffener is fastened to frames etc. with bolts of which at least two (2) on each side shall 2 be through bolts. The total gross sectional area, in cm , of the bolts at bottom of threads at each end shall not be less than:

where:

h ℓ

= bulkhead height, in m = span of stiffeners, in m.

Minimum bolt diameter is 16 mm. 5.6.4 The wooden board thickness, in mm, shall not be less than:

where:

tmin tmin ℓ h

= 76 mm for h ≥ 1.8 m = 63 mm for h < 1.8 m = greatest span between supports, in m = bulkhead height, in m.

5.6.5 For details, see [5.5.4], [5.5.5], [5.5.6], [5.5.8] and [5.5.9].

5.7 Transverse bulkheads with horizontal wooden boards 3

5.7.1 The gross section modulus, in cm , of uprights shall not be less than:

where:

h b

= free span of upright, in m = distance between uprights, in m.

5.7.2 The board thickness, in mm, shall not be less than:

where:

tmin tmin h

= 76 mm for h ≥ 2.0 m = 63 mm for h < 2.0 m = bulkhead height, in m

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 18

Part 5 Chapter 12 Section 2

b

= distance between uprights, in m, maximum 2.0 m.

5.7.3 For details, see [5.5.4], [5.5.5], [5.5.6], [5.5.8] and [5.5.9]. 2

5.7.4 The gross total area of attachment, e.g. bolts, in cm , at the lower end of removable uprights shall not be less than:

where:

h b

= bulkhead height, in m = distance between uprights, in m.

Minimum bolt diameter is 16 mm. 5.7.5 The gross sectional area at bottom of threads per bolt for bolted bulkheads shall be determined according to the formula in [5.7.4] when:

b

= bolt spacing, in m.

Minimum bolt diameter 16 mm. 5.7.6 The gross area of attachment at the top for single deck vessels can be 60% of the area stipulated in [5.7.4] and [5.7.5]. 5.7.7 All welds for the securing of bulkheads and uprights shall be of the double continuous type. 5.7.8 If a U-shaped collar is fitted around beams and keelson and secured with horizontal through bolts, the gross area of these bolts can be 60% of the area stipulated in [5.7.4] and [5.7.5]. 2

5.7.9 The total gross area of connection between horizontal stiffeners, in cm , mentioned in [5.4.1], shall not be less than:

where:

h ℓ

= bulkhead height, in m = distance, in m, between support of stiffeners.

5.8 Permanent steel bulkheads 3

5.8.1 The gross section modulus, in cm , of stiffeners on permanent longitudinal or transverse bulkheads shall be at least:

where:

b

= 3.75 for one longitudinal bulkhead = 4.5 for transverse bulkheads

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 19

Part 5 Chapter 12 Section 2

ℓ

ℓ s h

= stiffener span, in m = stiffener spacing, in m = height, in metres from midpoint, of stiffener span to top of bulkhead or hatch coaming. 4

5.8.2 The stiffener's gross moment of inertia, in cm , shall not be less than:

where:

Zgr

= as given in [5.8.1], with k = 1.0.

5.8.3 Permanent pillars which are welded to permanent bulkheads and also serve as guides for removable bulkheads in way of hatches shall have scantlings as given in [5.8.1] and [5.8.2], when s = breadth of load surface in m. Remaining symbols as under [5.8.1]. 5.8.4 The plate thickness in permanent steel bulkheads shall be as given in [5.9.2]. 5.8.5 Corrugated bulkheads will be accepted provided their strength is equivalent to that of plane bulkheads. 5.8.6 Stiffeners shall be fitted with brackets at both ends. The brackets are not to terminate on unstiffened plating or over a scallop. Care shall be taken, particularly at the bottom, that the corners of the corrugations do not end on unstiffened plating. 5.8.7 The various structural parts shall be connected by welding in accordance with the requirements for watertight bulkheads.

5.9 Removable bulkheads of steel or aluminium 5.9.1 Removable steel or aluminium bulkheads which are used in connection with hatches shall be double plated with the stiffeners placed horizontally. Internal surfaces of steel bulkheads shall be covered by a corrosion-resistant coating. 5.9.2 The gross plate thickness, in mm, of removable bulkheads shall not be less than: Steel:

Aluminium:

where:

s h

= stiffener spacing, in m = height, in m, from upper edge of bulkhead to lower edge of plating.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 20

Part 5 Chapter 12 Section 2

= 4.5 for 2 or more longitudinal bulkheads

Steel:

Aluminium:

ℓ, s and h are given in [5.8.1]. 2

5.9.4 For aluminium materials with a guaranteed 0.1% tensile proof stress (σ0.1) which exceeds 120 N/mm , the requirement to Zgr can be reduced in direct proportion. If however, the material's guaranteed σ0.2 value is greater than 70% of the guaranteed ultimate tensile strength, the lower value shall be used as a basis for scantlings. 4

5.9.5 The gross moment of inertia of stiffeners, in cm , shall not be less than:

where:

C

= 2.2 for steel = 5.75 for aluminium

Z

gr

= as given in [5.9.3] for steel, with k = 1.0.

5.9.6 When welding aluminium, attention should be paid to the reduced strength of the material in the weld area, and the weld should, where practicable, be positioned in less stressed areas. 5.9.7 Guides for removable bulkheads shall have brackets at 1 m spacing. The depth of the support at the sides of removable bulkheads shall be at least equal to the bulkhead thickness, and not less than 65 mm. The minimum thickness of sections or plates which form the guides, is 10 mm. 5.9.8 In order to prevent galvanic corrosion, insulation shall be fitted at connections or contact surfaces between steel and aluminium. 5.9.9 If necessary, removable bulkheads shall be equipped with a securing arrangement for preventing the bulkhead from floating. Slot welding is carried out against a 50 × 8 mm steel flat bar or equivalent. Removable aluminium bulkheads are presumed constructed of a sea-water resistant alloy.

5.10 Corrugated aluminium sections 5.10.1 Corrugated aluminium shifting boards may be used instead of horizontal wooden boards. The maximum length, in m, between supports shall not be greater than:

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 21

Part 5 Chapter 12 Section 2

3

5.9.3 The gross section modulus of horizontal stiffeners, in cm , shall not be less than:

m

= 0.6 for one longitudinal bulkhead = 0.5 for 2 or more longitudinal bulkheads = 0.4 for transverse bulkheads

h b IA

= bulkhead height, in m = board breadth, in m

4

= gross moment of inertia of board, in cm .

5.10.2 In order to prevent galvanic corrosion, insulation shall be fitted at connections or contact surfaces between steel and aluminium. 5.10.3 The corrugated boards shall be made of seawater resistant aluminium. 5.10.4 For details the same rules apply as for bulkheads with horizontal wooden boards.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 22

Part 5 Chapter 12 Section 2

where:

1 Bilge and drainage arrangement 1.1 Cargo holds for fish in bulk 1.1.1 There shall be good drainage for water, oil or brine from the cargo. Trunks and gutters shall be located such that they at all times will provide good drainage from all layers of the cargo, throughout the hold. 1.1.2 In each bin there shall be drainage to a bilge well through vertical drainage trunks of perforated plates, grating, etc. as specified in Table 1. The minimum acceptable perforated circumference per trunk is 0.3 m. The perforations shall consist of 4-8 mm holes or equivalent. Table 1 Drainage arrangement Area in m of bin below deck

Minimum number of drainage trunks per bin

Total length in m of trunk perforated circumference per bin

A < 10

2

0.8

10 ≤ A < 15

3

1.0

15 ≤ A < 20

3

1.2

20 ≤ A < 25

4

1.4

25 ≤ A < 30

4

1.6

30 ≤ A < 35

5

1.8

2

1.1.3 Each cargo hold shall have a bilge well at its after end. If the length of the watertight compartment exceeds 9 m, there shall be a bilge well also at the forward end. 3

Each bilge well shall have a volume not less than 0.15 m . 1.1.4 From each bilge well, a separate branch suction line shall be led to the engine room. The bilge distribution valves shall be of screw-down non-return type. All valves shall be fitted in readily accessible positions. 1.1.5 The valve chest collecting branch suction lines from cargo holds for fish in bulk shall have no connections from dry compartments. The valve chest shall be directly connected to the largest bilge pump. In addition, a connection shall be provided to another bilge pump. 1.1.6 The internal diameter of the branch suction lines shall be as required in Pt.4 Ch.6 for main bilge lines. Minimum diameter 50 mm. 1.1.7 Means for back-flushing bilge suctions shall be provided. The connecting of water supply for backflushing shall be by portable means, e.g. hose.

1.2 Tanks for fish in refrigerated sea water tanks (RSW-tanks) 1.2.1 The RSW-tanks shall have a pumping system for filling and emptying of seawater. The system shall have pipe dimensions complying with the requirements for ballast systems.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 23

Part 5 Chapter 12 Section 3

SECTION 3 SYSTEMS AND EQUIPMENT

1.2.3 Where RSW-tanks are also arranged for carrying dry cargo, blank flanging or two closable valves in series to avoid ingress of water from RSW system to the bilge system are required.

1.3 Tween deck for fish in bulk 1.3.1 Fishing vessels intended for carrying fish loose on tween deck shall have a satisfactory arrangement for drainage of tween deck. The drainage may be led to bilge well in the hold below or arranged as given in [1.1.4] to [1.1.7]. 1.3.2 For tween deck compartments having no openings where sea may penetrate and where no processing requiring supply of water is taking place, drainage to bilge will in the engine room may be accepted. The drainage pipes are normally not to exceed 50 mm in diameter and shall have a self-closing valve at the engine room side. 1.3.3 For combination vessels, i.e. longline, net fishing, etc. an efficient drainage system shall be provided for all weathertight divisions/compartments in addition to the drainage from tween deck.

1.4 Engine room bilge water monitoring Alarm for high level in bilge wells in engine room shall be installed on the bridge.

2 Prevention of tween deck flooding 2.1 Arrangement of side openings leading to tween deck (working deck) 2.1.1 Arrangement and closing appliances of openings in side which will normally be open when the vessel is at the fishing grounds, shall be in accordance with [2.1.2] to [2.1.5]. 2.1.2 Doors in vessel's side and stern shall be limited in size and number to the minimum possible. The sill height is normally not to be less than 1000 mm. The doors with securing devices shall be designed with a strength equivalent to the structure in which they are fitted, and shall be so arranged that weathertight quick closing (approximately 15 second for side doors), can be easily executed by one member of the crew without the use of tools. This shall be possible also during black-out. If arranged with remote closing from the bridge, a signal light shall be fitted at the port(s), warning automatically when closing is executed. To avoid injury when closing, TV monitoring of the door(s) or means of communication according to Sec.4 [1.1.2] shall be arranged. Signboard with the following text to be fitted: “To be kept closed when not in use during fishing”. 2.1.3 Each opening for drainage by pumps from drainage wells shall be fitted with a type approved automatic non-return flap with manual means of closing operable from 1.5 m above the deck. The inboard opening shall be situated not lower than 0.02 Loa, or minimum 0.7 m above the maximum loaded waterline. 2.1.4 Drainage flaps leading directly overboard from drainage wells shall be limited to the minimum possible in size and number, and shall be flush with hull to avoid damage. Drainage flaps shall have vulcanised surfaces and be easy to flush clean. Drainage flaps shall be easily accessible for cleaning and survey. Remote closing from the bridge shall be arranged in addition to manual means of closing operable from 1.5 m above the deck. A panel on the bridge shall show which flaps are open/closed.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 24

Part 5 Chapter 12 Section 3

1.2.2 If the tanks shall also be used for carrying dry cargo, the tanks shall be arranged with a bilge system. If the tanks shall be used for carrying fish in bulk, the requirements given in [1.1.3] and [1.1.4] shall also be complied with.

2.2 Drainage of tween deck with openings in side 2.2.1 Tween deck with openings according to [2.1.1] shall be arranged with a drainage system in accordance with [2.2.2] to [2.2.7]. 2.2.2 Drainage shall be carried out using separate pumps in drainage wells at side at the lowest position of the working deck. For vessels with a working deck of length greater than 9 m, drainage wells shall be fitted forward and aft. For working decks of length greater than B/2, drainage wells shall be fitted on both sides. 2.2.3 The volume of each drainage well shall not be less than:

where: 3

V As ℓ

= volume of drainage well, in dm

= area of the side port(s) at each side, in m

2

= length of working deck in m. 3

The volume shall in no case be less than 0.15 m , and the depth of each well shall be at least 0.35 metres. 2.2.4 The arrangement of drainage wells shall provide for effective drainage and avoidance of clogging by fishing hooks and fish waste of pump suction. 3

2.2.5 The capacity of each bilge pump, in m /h, shall not be less than: where: Q

min

3

= 1.25 times available wash-down capacity in m /h, for each side.

2.2.6 Bilge pumps shall be fitted with manual start/stop, and be designed to pump fish waste together with drainage water. Outlet shall be in accordance with [2.1.3]. 2.2.7 Alarm for free water on tween (working) deck shall be installed on the bridge. The alarm shall be activated when the drainage wells are full. 2.2.8 In addition to the arrangement described in [2.2.2] to [2.2.7], drainage flaps according to [2.1.4] may be installed in the drainage wells if necessary. The freeboard shall not be less than to the lower edge of the drainage flap opening, or 0.35 m measured from the deck.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 25

Part 5 Chapter 12 Section 3

2.1.5 Inboard openings of garbage chutes for disposal of fish waste, shall be located minimum 0.7 m above the maximum loaded water line. The inboard end shall be fitted with a weathertight hinged cover and necessary number of securing devices. The outboard end shall be fitted with a watertight closeable nonreturn valve operable from 1.5 m above deck. The arrangement shall be easy to flush clean, and be easily accessible for survey.

Closing appliances for openings from tween deck to spaces below deck, or to closed superstructure which is considered buoyant in the stability calculations, shall be in accordance with Sec.6 [2.2.6].

3 Enclosed tween deck 3.1 Enclosed tween deck where water is used in processing 3.1.1 Any arrangement of garbage chutes shall be in accordance with [2.1.5]. 3.1.2 Drainage from drainage wells shall be carried out by pumps. If the arrangement is based on separate pumps situated in each drainage well as in [2.2.1] to [2.2.7], the outlet shall be in accordance with [2.1.3]. The number and location of drainage wells shall be arranged so that satisfactory drainage is achieved. The 3 capacity of drainage pumps shall be at least 1.25 times available wash-down capacity in m /h, for each side.

4 Spaces with refrigeration installations of direct expansion type 4.1 Refrigeration plant The refrigeration machinery room and the refrigeration system shall comply with the requirements in Pt.4 Ch.6 Sec.6.

4.2 Refrigerated holds for stowage of frozen fish/fish products 4.2.1 Access/exits In holds where personnel may be engaged in stowing frozen fish products, the exit(s) shall be arranged so that escape is easy, preferably by inclined stairs. The escapeway(s) shall be suited for carrying a disabled person out of the hold. Cooled/frozen cargo chambers with direct expansion air coolers and with vertical access, if they are normally manned such as on fishing vessels and on fish factory ships, shall be fitted with permanent hoisting arrangements for removal of injured/unconscious crew members. Exit doors shall open outwards. In case ammonia (R717) is the refrigerant, gas masks shall be placed close to the normal access to the hold. If the normal exit from the hold is through a space containing refrigeration equipment, e.g. fish processing space, gas masks shall be available from inside the hold enabling personnel to escape. Alarm signals, optical and audible, shall be fitted inside the hold giving warning in case of refrigerant leakage in the adjacent space. Access doors and hatches shall either be operable from both sides or be fitted with catches to prevent inadvertent closing. If air pipes for tanks or sea chests and water pipes are passing through freezing chambers or its insulation, they shall be arranged to prevent freezing. All holds and air cooler rooms are each to be fitted with at least one conveniently located alarm call button. 4.2.2 Refrigerant leakage detection A refrigerant leakage detection system shall be fitted. For refrigerants in group 1, except CO2, an oxygen deficiency monitoring may be accepted in lieu of refrigerant gas detection.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 26

Part 5 Chapter 12 Section 3

2.3 Arrangement of openings from tween deck to other spaces

Ammonia (R717)

: 150 PPM

CO2 (R744)

: 2000 PPM.

The detectors shall be suitable for use in the low temperature environment and shall be calibrated for same. 4.2.3 Ventilation Arrangements for mechanical ventilation of the hold in case of a refrigerant leakage shall be available. The ventilation may be either fixed or portable type.

4.3 Fish processing decks/spaces 4.3.1 Access/exits At least two exits from the space shall be provided. If R717 is the refrigerant the location of the exits shall be such that a possible refrigerant leakage will not block access to both exits. The normally used access/exits shall have outward opening doors. 4.3.2 Ventilation The normal ventilation shall be separate for the space and may be natural or mechanical. Mechanical ventilation shall be of extraction type. If R717 or R744 being the refrigerant, additional mechanical ventilation shall be available in case of leakage is detected. The ventilation capacity shall be at least six (6) air changes per hour. Starting of additional ventilation shall be automatically initiated in case a refrigerant leakage is detected. Ventilation outlets shall be located away from ventilation inlets to other spaces and away from areas where personnel is normally present. The emergency stop arrangements for fans required by rules Pt.4 Ch.8 Sec.2 [8.6.2] shall be separate for the fans. 4.3.3 Refrigerant leakage detection Refrigerant gas detection shall be fitted. Detectors should be located at ventilation suction points and at suitable locations within the space. A minimum of two (2) detectors per space is required. Alarm signals, optic and audible, shall be located within the space and in way of accesses to the space. When R717 is used, refrigerant leakage shall be detected at three different consecutive levels with set points not higher than: 150 ppm

: Initial leakage detection.

350 ppm

: Start ventilation and evacuate the space.

5000 ppm

:

Stop refrigerant circulation pumps and close refrigerant supply and return valves required by Pt.4 Ch.6 Sec.6 [4.2.2].

Separate alarm indication in the navigation bridge shall be fitted. If the refrigerant is CO2 (R744) alarm, automatic starting of ventilation and closing of refrigerant supply and return valves shall be executed at a concentration of 2000 ppm. For refrigerants in group 1 except R744 oxygen deficiency alarm may be accepted as alternative to refrigerant gas detection.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 27

Part 5 Chapter 12 Section 3

In case the refrigerant is ammonia or CO2, gas leakage detection shall be fitted. Alarm shall be triggered as follows:

If R717 is used as refrigerant, the emergency lighting in the space and ventilation fan motors shall be excertified and the fans of non-sparking design. 4.3.5 Personnel protection In case R717 is the refrigerant the following shall be provided: — Gas masks and hermetically sealed filters shall be available in a glass door case located outside each entrance to the space. — Outside all access doors water screens and eye washes shall be provided. The water screens/eye washes shall be operable also under freezing conditions.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 28

Part 5 Chapter 12 Section 3

4.3.4 Electrical equipment

1 Design requirements 1.1 Internal communications 1.1.1 A general emergency alarm system shall be provided on all fishing vessels and stern trawlers. 1.1.2 If the tween deck is fitted with side openings, two-way voice communication, fixed or portable, shall be provided between the bridge and in way of the doors in the vessel's side and stern. Alternatively, TV monitoring may be provided. 1.1.3 For electrical requirements refer to Pt.4 Ch.8 Sec.2.

2 Fire safety 2.1 Application 2.1.1 Fishing vessels of less than 500 gross tonnage (according to IMO’s International Convention on Tonnage Measurements of Ships, 1969) or less than 45 m length, LLL shall comply with the requirements for cargo ships given in Pt.4 Ch.11 Sec.2 and to [2.5.3] and [2.5.4]. 2.1.2 Fishing vessels of 500 gross tonnage (according to IMO’s International Convention on Tonnage Measurements of Ships, 1969) and above, or 45 m length, LLL, and above shall comply with the requirements specified in Sec.1 [3.1], and [2.2] to [2.7]. 2.1.3 Vessels complying with the fire safety requirements applicable for a new vessel in Torremolinos International Convention for the Safety Of Fishing Vessels 1977, as modified by the Torremolinos Protocol of 1993, or equivalent standards such as the Council Directive 97/70/EC of 11 December 1997 as amended, (setting up a harmonised safety regime for fishing vessels of 24 meters in length and over) or national regulations, need not comply with the requirements referred to in [2.1.1] and [2.1.2] above.

2.2 Fire pumps and water distribution system Fire pumps and water distribution systems shall comply with the requirements in SOLAS Ch. II-2 Reg. 10.2 as applicable for cargo ships.

2.3 Fire safety arrangement in machinery spaces 2.3.1 The arrangement of fixed total flooding extinguishing system and fire-extinguishing appliances in machinery spaces shall comply with the requirements in SOLAS Ch. II-2 Reg. 10.5 as applicable for cargo ships. Local application system according to Reg. 10.5.6 will not be required. 2.3.2 Escape arrangements in machinery spaces shall comply with the requirements of SOLAS Ch. II-2 Reg. 13.4.2. This will be reviewed in connection with approval of the structural fire protection plan. 2.3.3 Detection in periodically unattended machinery spaces will only be reviewed if the class notation E0 is requested.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 29

Part 5 Chapter 12 Section 4

SECTION 4 FIRE SAFETY AND LIFESAVING APPLIANCES

Fishing vessels shall be provided with at least two sets of fire-fighter’s outfits complying with SOLAS Ch. II-2 Reg. 10.10.

2.5 Fire protection of bulkheads and decks 2.5.1 Structural fire protection shall comply with the requirements in SOLAS Ch. II-2 Reg. 9.2 as applicable for cargo ships. Method of protection as defined in Reg. 2.3.1 should be IC. 2.5.2 Materials shall comply with the requirements in SOLAS Ch. II-2 Reg. 5.3 and 6 as applicable for cargo vessels. 2.5.3 Combustible insulation materials are accepted in compartments for stowage of fish provided low ignitability and low flame spread properties are documented. See Sec.1 [4.1] for testing requirements. 2.5.4 Combustible insulation as accepted by [2.5.3] shall be protected by close-fitting cladding. Acceptable cladding is steel sheet and marine plywood. Surface coatings shall have low flame spread properties.

2.6 Portable fire extinguishers Portable fire extinguishers shall be provided in accordance with the requirements in SOLAS Ch. II-2 Reg. 10.3 as applicable for cargo ships.

2.7 Fire control plan Fire control plans shall be provided as to comply with the requirements in SOLAS Ch. II-2 Reg.15.2.4.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 30

Part 5 Chapter 12 Section 4

2.4 Fire-fighter’s outfits

1 Electrical power generation and distribution 1.1 General 1.1.1 The electrical power generation and distribution systems shall generally be in compliance with the requirements given in Pt.4 Ch.8. However, the system design requirements given in Pt.4 Ch.8 reflect requirements given in the SOLAS convention, and in relevant IMO regulations. The system design for a fishing vessel may be modified in line with applicable international and/or national regulations applicable to such vessels, as noted in Sec.1 [5]. This implies e.g. that a division of the main bus-bar may not be required. Further, that requirements to installation and location of the emergency source of power may be somewhat relaxed. Guidance note: The flag administration may have requirements for the same as found in [1.1.1]. The stricter one is expected to prevail. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 31

Part 5 Chapter 12 Section 5

SECTION 5 ELECTRICAL SYSTEMS

1 Stability 1.1 Application 1.1.1 Vessels with class notations Fishing vessel or Stern trawler with length LLL of 24 metres and above shall comply with the requirements of Pt.3 Ch.15 (as far as applicable), as well as the requirements of this subsection. The rules cover IMO 2008 Intact Stability Code as applicable for fishing vessels, and Chapter III of the Torremolinos International Conference for the Safety of Fishing Vessels, as modified by the Torremolinos Protocol of 1993, with the exception of Regulation 14.

1.2 Stability criteria 1.2.1 The following general criteria apply: — The area under the righting lever curve (GZ curve) shall not be less than 0.055 metre-radians up to θ = 30° angle of heel and not less than 0.09 metre-radians up to θ = 40° or the angle of flooding θf if this angle is less than 40°. Additionally, the area under the righting lever curve (GZ curve) between the angles of heel of 30° and 40° or between 30° and θf, if this angle is less than 40°, should not be less than 0.03 metre-radians. — The righting lever GZ shall be at least 0.20 m at an angle of heel equal to or greater than 30°. — The maximum righting arm should occur at an angle of heel not less than 25°. Guidance note: In case the vessel's characteristics render compliance with the above criterion impracticable, the alternative criteria as given in Pt.3 Ch.15 Sec.1 [4.1.3] may be applied upon special consideration. ---e-n-d---o-f---g-u-i-d-a-n-c-e---n-o-t-e---

— The initial metacentric height shall not be less than 0.35 meters in any operating condition. 1.2.2 The metacentric height GM in light ship condition shall be positive. 1.2.3 Fishing vessels of 45 m in length (LLL) and over shall comply with the weather criterion of Pt.3 Ch.15 Sec.1 [4.2.1]. 1.2.4 Fishing vessels in the length range 24 m ≤ LLL < 45 m shall comply with the weather criterion of Pt.3 2 Ch.15 Sec.1 [4.2.1], but the values of wind pressure, N/m , shall be taken from Table 1. Table 1 Wind pressure h in m P in N/m

h

2

1

2

3

4

5

6 and over

316

386

429

460

485

504

= Vertical distance from the centre of the projected vertical area of the ship above waterline, to the waterline.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 32

Part 5 Chapter 12 Section 6

SECTION 6 STABILITY AND LOAD LINE

1.3.1 Compliance with the stability criteria shall be documented for the following standard loading conditions: — departure for the fishing grounds with full fuel, fresh water, stores, ice, fishing gear, etc. — departure from the fishing grounds with full catch, at maximum draught and no more than 30% fuel, fresh water and stores — arrival at home port with full catch and 10% fuel, fresh water and stores remaining — arrival at home port with 20% of full catch and 10% fuel, fresh water and stores remaining — at fishing grounds with maximum catch on deck, hold empty and 50% fuel, fresh water and stores remaining (if consistent with fishing method). 1.3.2 Special loading conditions associated with a change in the vessel's mode or area of operation which affect the stability, shall be considered. 1.3.3 If water ballast shall be filled between departure and arrival in order to meet the stability criteria, a loading condition shall be included showing when the water ballast shall be taken on board. The condition shall show the situation just before ballasting, with the maximum free surface moments of the ballast tank(s) included. 1.3.4 Allowance for the weight of wet fishing net and tackle on deck, shall be included if applicable. 1.3.5 Allowance for ice accretion according to [1.4.1] shall be shown in the worst operating condition in the stability booklet, if consistent with area of operation. 1.3.6 Homogeneous distribution of catch in all holds, hatch coamings and trunks shall be assumed, unless this is inconsistent with practice. (Volumetric centre of gravity and identical specific gravity for all holds available for catch). 1.3.7 Catch on deck shall be included in the loading conditions showing departure from fishing grounds and arrival at port, if this is consistent with practice. 1.3.8 Free surface effect of catch shall be included, if relevant. 1.3.9 Free surface effect of water in fish bins shall be included in loading condition at fishing grounds, if relevant. 1.3.10 In all loading conditions, full fishing gear and equipment shall be assumed.

1.4 Ice consideration 1.4.1 The calculation of weight and centre of gravity of the ice accretion, shall be based on the following assumptions: — 30 kg per square metre on exposed weather decks and gangways — 7.5 kg per square metre for projected lateral area of each side of the vessel above the water plane — the projected lateral area of discontinuous surfaces of rail, sundry booms, spars (except masts) and rigging of vessels having no sails and the projected lateral area of other small objects should be computed by increasing the total projected area of continuous surfaces by 5% and the static moments of this area by 10%.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 33

Part 5 Chapter 12 Section 6

1.3 Loading conditions

1.5.1 When equipped with roll reduction tanks, the reduction in stability due to the effect of these tanks shall be allowed for in the loading conditions. 1.5.2 If the roll reduction tanks can not be used in all conditions of loading, an instruction on the use of these tanks and corresponding limit conditions shall be included in the stability booklet. These limit conditions shall show the stability of the vessel just before emptying the roll reduction tanks.

1.6 Water on deck and in compartments temporarily open to sea 1.6.1 Accumulation of water on deck shall be assumed if the requirements on freeing port area (see [2.2.15]) are not fully met, or if the design of the weather deck is such that water may be trapped. The stability calculations shall take the effect of this water into account according to the requirements of [1.6.3] to [1.6.5]. 1.6.2 If hatches or similar openings shall be left periodically open during operation, the stability calculations shall take the effect of water in the open compartment(s) into account according to the requirements of [1.6.3] to [1.6.5], provided that the angle of down-flooding for the critical opening is less than 30°.

Figure 1 Water on deck criterion 1.6.3 The ability of the vessel to withstand the heeling effect due to the presence of water on deck, shall be demonstrated by a quasi-static method. With reference to Figure 1, the following criterion shall be satisfied with the vessel in the worst operating condition: — area b shall be equal to or greater than area a. The angle that limits area b shall be taken as the angle of down-flooding (θf) or 40°, whichever is less. 1.6.4 The value of the heeling moment MW (or the corresponding heeling arm), due to the presence of water on deck shall be determined assuming that the deck well is filled to the top of the bulwark at its lowest point (or the flooding point of the open compartment). The vessel shall be heeled up to the angle at which this point is immersed (θD), where the heeling moment MW (or the corresponding heeling arm), shall be terminated.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 34

Part 5 Chapter 12 Section 6

1.5 Roll reduction tanks

— at the beginning the vessel is in the upright condition — during heeling, trim and displacement are constant and equal to the values for the vessel without the water on deck — the effect of freeing ports shall be ignored.

1.7 Onboard cranes 1.7.1 The effect on the stability of cranes when used for fishing operations, shall be considered in the stability calculations in accordance with the requirements given in [1.7.2] to [1.7.4]. 1.7.2 The maximum possible crane heeling moment shall be assumed. The following shall be considered in the calculation of this moment: — combination of safe working load on hooks and crane radius — weight and position of boom relative to crane axis — two cranes (or more) working in combination (if consistent with practise). 1.7.3 When the effect of the crane heeling moment is checked, the vertical centre of gravity of the loading condition shall be calculated with load on crane hooks. When the static heeling angle exceeds 5°, the heeling lever shall be drawn in the GZ diagram for the critical loading condition(s). Cranes shall not be used at sea, unless it can be demonstrated that the residual stability is sufficient. 1.7.4 Information on operational limitations on use of cranes, if any, shall be included in the stability booklet. This could include limitations on allowable load on hooks for certain conditions of loading. The maximum heeling moment calculated according to [1.7.2] shall be stated in the stability booklet

1.8 Forces from fishing gear 1.8.1 When special arrangement of the fishing gear (e.g. trawls or purse seines) result in significant forces on the vessel with impact on the stability, this shall be considered in the stability calculations.

1.9 Stability for vessels with qualifier N 1.9.1 Vessels complying with the requirements for stability in paragraph 11 of the 1993 regulations of the Norwegian Maritime Authority for FISKE- OG FANGSTFARTØY and the bow height requirements in [2.4], may have the qualifier N.

2 Load line 2.1 Freeboard 2.1.1 General requirements A vessel shall have a draught mark on each side. Draught marks shall be fitted on the sides at midship corresponding to the approved draught with respect to strength and stability. The draught marks shall be in the form of horizontal lines (450 mm long, 25 mm in height) with the letters VL placed 25 mm above the lines (letter dimensions: height - 115 mm, breadth - 75 mm, thickness - 25 mm). The marks shall be permanent, and be painted in contrasting colour.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 35

Part 5 Chapter 12 Section 6

1.6.5 When calculating MW the following assumptions shall be made:

2.1.3 If the freeboard deck surface outside of weathertight enclosed superstructure in any place is lower, measured to the design waterline, than at midship where the draught mark is placed, the minimum freeboard at midship shall be corrected accordingly, so that no part of exposed freeboard deck is lower than the loaded waterline. 2.1.4 Vessels with open connection to sea from fishing wells/tanks for live fish shall have the same freeboard for summer and winter. The freeboard shall be minimum 100 mm. 2.1.5 The freeboard may be taken equal to zero provided a closed superstructure of length not less than 0.45 LLL is fitted.

2.2 Openings and closing appliances 2.2.1 Coaming and sill height, closing appliances, freeing ports Coaming and sill heights, closing appliances, freeing port areas, air pipes, ventilators, sanitary discharges etc. shall be in accordance with the requirements in Pt.3 Ch.12, except as otherwise specified in this subsection. 2.2.2 The height above deck of sills in those doorways, in companionways, erections and machinery casings which give direct access to parts of the deck exposed to the weather and sea shall be at least 600 mm on the freeboard deck and at least 300 mm on the superstructure deck subject to special consideration, where operating experience has shown justification, these heights, except in the doorways giving direct access to machinery spaces, may be reduced to not less than 380 mm and 150 mm, respectively. 2.2.3 Weathertight doors leading to spaces below freeboard deck and to enclosed superstructure included as buoyant in the stability calculations, shall be positioned as close to the vessel's centreline as possible. Weathertight doors shall have a standard equivalent to ISO 6042. Spraytight doors of a standard equivalent to ISO may be accepted as weathertight doors on vessels with service restriction R2 and in general for doors in bulkheads which are facing aft and on doors on tween deck in enclosed superstructure. 2.2.4 The height above deck of hatchway coamings shall be at least 600 mm on exposed parts of the freeboard deck and at least 300 mm on the superstructure deck. 2.2.5 Where operating experience has shown justification, and subject to special consideration, the height of the hatchway coamings may be reduced, or the coamings omitted entirely, provided that the safety of the vessel is not thereby impaired. In this case, the hatchway openings shall be kept as small as practicable and the covers be permanently attached by hinges or equivalent means and be capable of being rapidly closed and battened down, or by equally effective arrangements. 2.2.6 Flush deck hatches used for catch of fish should normally be led to a tank or a watertight fish bin. The door/hatch allowing the fish to flow into the processing area shall be interlocked with the flush deck hatches, i.e. one has to close before the other can open. The closing arrangements of the door/hatches shall be operated from deck. 2.2.7 Hatch covers shall be weather- or watertight, with gaskets and necessary securing devices. For hatch 2 covers of more than 4 m , small hatch covers shall be installed as close to the vessel's centreline as possible for use during operation. Such hatch covers shall have securing devices also at the hinged side. Hinged hatch covers shall be securable in open position. 2.2.8 Coaming height and sill height for hatches and doors on working deck in enclosed superstructure and deckhouses where water are used in the working process shall not be less than 100 mm.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 36

Part 5 Chapter 12 Section 6

2.1.2 The freeboard measured from the loaded waterline to the surface of freeboard deck at side, shall in no circumstance be less than 0 mm.

2.2.10 Closing appliances in vessels of 45 m in length (LLL) and over need not be fitted to ventilators the coamings of which extend to more than 4.5 m above the freeboard deck or more than 2.3 m above the superstructure. In vessels of less than 45 m in length (LLL), closing appliances need not be fitted to ventilators the coamings of which extend to more than 3.4 m above the freeboard deck or more than 1.7 m above the superstructure deck. 2.2.11 Below the freeboard deck and in enclosed superstructure on freeboard deck, side scuttles with hinged deadlights shall be used. 2.2.12 Sidescuttles and windows may be accepted without deadlights in side and aft bulkheads of deckhouses located on or above the freeboard deck if satisfied that the safety of the vessel will not be impaired. 2.2.13 Sidescuttles and windows prone to be damaged by fishing gear shall be suitably protected. 2.2.14 Side scuttles in ship sides, including outboard side of enclosed superstructure and deckhouses at ship sides, shall not be closer to the loaded waterline than 500 mm. Such side scuttles shall be equipped with hinged deadlights. Side scuttles closer to the loaded waterline than 1000 mm shall not be possible to open. 2

2.2.15 The freeing port area, in m , on each side of net bins and other short wells on deck with length less than 5 m, may be calculated using the following formula:

where:

ℓ = length of well, in m. In short wells of less than 3 m, the freeing port area may be specially considered. Covers of freeing ports shall be non-closable and hinged in upper edge.

"Well"

"Recess"

Freeboard length:

Figure 2 Parameters for calculation of freeing port area

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 37

Part 5 Chapter 12 Section 6

2.2.9 In vessels of 45 m in length and over, the height above deck of ventilator coamings, other than machinery space ventilator coamings, shall be at least 900 mm on the freeboard deck and at least 760 mm on the superstructure deck. In vessels of less than 45 m in length, the height of these coamings shall be 760 mm and 450 mm respectively.

2.2.17 Ordinary freeing ports in high bulwarks (more than 1 meter in height), or in sides of open superstructure, are not considered as sufficient for drainage of exposed freeboard deck (may be accepted for vessel with service notation RE). Open superstructure such as open forecastle, separate walls at side or other similar constructions are therefore not acceptable, unless the stability requirements of [1] for water on deck are complied with, or if sufficient drainage is provided according to [2.2.18]. 2.2.18 For vessels where the sea may enter over the stern and flood the deck into a superstructure which is 2 open in aft end, the freeing port area, in m , on each side shall not be less than required by the following:

Where the length of the bulwark in the well, ℓ2, is 20 metres or less, the freeing port areas on each side, in 3 m , in way of the recess and the well are not to be less than:

ℓ1 need in no case be taken as greater than 0.7 LLL. where:

ℓ1 ℓ2 y1

= length of deck, in m, as defined in Figure 1

y2

= 1.5 for no shear

h

= average height of bulwark aft of the open superstructure, in m.

= length of bulwark in the well, in m, as defined in Figure 1 = 0.5 for superstructure deck = 1.0 for freeboard deck = 1.0 for suitable shear applied

Other parameters are defined by Figure 2. 2.2.19 For non-watertight fish bins, a drainage system is required in order to prevent flooding of the working deck area. 2.2.20 Freeing ports over 300 mm in depth shall be fitted with bars spaced not more than 230 mm nor less than 150 mm apart or provided with other suitable protective arrangements. Freeing port covers, if fitted, shall be of approved construction. If devices are considered necessary for locking freeing port covers during fishing operations they shall be easily operable from a readily accessible position. 2.2.21 Poundboards and means for stowage of the fishing gear shall be arranged so that the effectiveness of freeing ports will not be impaired. Poundboards shall be so constructed that they can be locked in position when in use and shall not hamper the discharge of shipped water. 2.2.22 In vessels intended to operate in areas subject to icing, covers and protective arrangements for freeing ports shall be capable of being easily removed to restrict ice accretion. The size of openings and means provided for removal of these protective arrangements shall be considered.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 38

Part 5 Chapter 12 Section 6

2.2.16 For non-watertight fish bins, a drainage system is required in order to prevent flooding of the working deck area.

2.3.1 Signboards are required by the rules in: — Sec.3 [2.1.2] concerning side doors.

2.4 Bow height for vessels with qualifier N 2.4.1 The bow height in mm measured vertically at the forward perpendicular from the loaded waterline to the exposed deck, shall be at least: 43 Loa + 310, for vessels up to Loa = 24 m 48 Loa + 190, for vessels with Loa = 24 m and above. 2.4.2 For vessels of 50 gross tonnage and above, the loaded waterline is the summer load line parallel to the design waterline. 2.4.3 For vessels below 50 gross tonnage, the loaded waterline is a waterline parallel with the design waterline corresponding to a freeboard of 100 mm at midship. 2.4.4 The required bow height is considered as complied with when the height is measured from: — the freeboard deck, having an approximately even sheer from midship to the forward perpendicular — deck of weathertight enclosed forecastle with length of at least 0.1 Loa, and with sheer in forecastle deck (with this minimum forecastle length) not greater than the sheer of the freeboard deck. With small or no sheer in freeboard deck, the length of weathertight enclosed forecastle may have to be increased.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 39

Part 5 Chapter 12 Section 6

2.3 Signboards

January 2017 edition

Main changes January 2017, entering into force July 2017 • Sec.2 Hull — Sec.2 [3.1.1]: Modification of the formula for minimum thickness has been made.

July 2016 edition

Main changes July 2016, entering into force 1 January 2017 • Sec.2 Hull — Sec.2 [1.3.3]: Strength criteria of lining plats introduced. — Sec.2 [1.3.4]: Specified density of polyurethane foam removed.

• Sec.3 Systems and equipment — Sec.3 [4.3.2]: Requirement for 30 air changes per hour has been changed to 6 air changes per hour.

October 2015 edition This is a new document. The rules enter into force 1 January 2016.

Amendments January 2016 • Sec.1 General — Table 2: The table has been updated to only contain additional class notations that are particularly fit for this ship type.

Rules for classification: Ships — DNVGL-RU-SHIP Pt.5 Ch.12. Edition July 2017 Fishing vessels

DNV GL AS

Page 40

Part 5 Chapter 12 Changes – historic

CHANGES – HISTORIC

About DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification, technical assurance, software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our experts are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER

RULES FOR CLASSIFICATION Ships Edition October 2015 Amended January 2016

Part 5 Ship types Chapter 13 Naval and naval support vessels

The content of this service document is the subject of intellectual property rights reserved by DNV GL AS ("DNV GL"). The user accepts that it is prohibited by anyone else but DNV GL and/or its licensees to offer and/or perform classification, certification and/or verification services, including the issuance of certificates and/or declarations of conformity, wholly or partly, on the basis of and/or pursuant to this document whether free of charge or chargeable, without DNV GL's prior written consent. DNV GL is not responsible for the consequences arising from any use of this document by others.

The electronic pdf version of this document, available free of charge from http://www.dnvgl.com, is the officially binding version.

DNV GL AS

FOREWORD DNV GL rules for classification contain procedural and technical requirements related to obtaining and retaining a class certificate. The rules represent all requirements adopted by the Society as basis for classification.

©

DNV GL AS October 2015

Any comments may be sent by e-mail to [email protected] If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shall pay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million. In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers, employees, agents and any other acting on behalf of DNV GL.

Part 5 Chapter 13 Changes - current

CHANGES – CURRENT This is a new document. The rules enter into force 1 January 2016.

Amendments January 2016 • General — Only editorial corrections have been made.

Editorial corrections In addition to the above stated changes, editorial corrections may have been made.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 3

Changes – current.................................................................................................. 3 Section 1 General.................................................................................................. 14 1 Introduction.......................................................................................14 1.1 General..........................................................................................14 1.2 International codes and regulations...................................................14 1.3 Application..................................................................................... 14 2 Class notations.................................................................................. 15 2.1 Ship type notations.........................................................................15 2.2 Additional notations........................................................................ 15 3 Definitions..........................................................................................16 3.1 Terms............................................................................................ 16 4 Classification of newbuildings........................................................... 17 4.1 General requirements for documentation........................................... 17 4.2 Classification basis.......................................................................... 17 4.3 Yard qualification............................................................................ 17 4.4 Working relations............................................................................ 17 4.5 Certification of components and equipment........................................ 18 4.6 Confidentiality................................................................................ 18 4.7 Area identification........................................................................... 18 5 Deviations from the rules.................................................................. 18 5.1 General..........................................................................................18 Section 2 Arrangements........................................................................................ 19 1 Deck arrangements............................................................................19 1.1 Deck definitions.............................................................................. 19 1.2 Rescue area................................................................................... 19 1.3 Guard-rails and handholds............................................................... 19 2 Watertight compartments.................................................................. 19 2.1 Watertight boundaries..................................................................... 19 3 Zones................................................................................................. 19 3.1 General principle.............................................................................20 3.2 Fire control zones........................................................................... 20 3.3 Damage control zones..................................................................... 20 3.4 Gastight division............................................................................. 20 3.5 Hazardous areas............................................................................. 20

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 4

Part 5 Chapter 13 Contents

CONTENTS

1 General requirements........................................................................ 21 1.1 General..........................................................................................21 2 Operational loads...............................................................................21 2.1 General..........................................................................................21 3 Accidental loads.................................................................................21 3.1 Local damage................................................................................. 21 3.2 Global damage............................................................................... 21 Section 4 Structural strength................................................................................ 22 1 General requirements........................................................................ 22 1.1 Structural strength..........................................................................22 2 Structural arrangement..................................................................... 22 2.1 Main structure................................................................................ 22 2.2 Bulkheads...................................................................................... 22 2.3 Mast for support of sensors and sensor’s systems............................... 22 3 Local strength....................................................................................22 3.1 Minimum thickness......................................................................... 22 3.2 Local structure............................................................................... 23 3.3 Damage of local structure................................................................23 4 Global strength.................................................................................. 23 4.1 General..........................................................................................23 5 Weld connections...............................................................................23 5.1 Application of fillet welds................................................................. 23 6 Direct strength calculations............................................................... 24 6.1 Modelling of hull structure............................................................... 24 Section 5 Stability, watertight and weathertight integrity.................................... 25 1 General.............................................................................................. 25 1.1 Applicability....................................................................................25 1.2 Plans and calculations..................................................................... 25 2 Intact stability requirements............................................................. 25 2.1 Loading conditions.......................................................................... 25 2.2 Calculation of stability..................................................................... 26 2.3 Calculation of effects from external loads...........................................27 2.4 Intact stability for monohull vessel................................................... 29 2.5 Intact stability for multihull vessels................................................... 31 3 Internal watertight integrity..............................................................31 3.1 Watertight subdivision..................................................................... 31

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 5

Part 5 Chapter 13 Contents

Section 3 Design loads.......................................................................................... 21

3.3 Extent of damage for multihull vessels.............................................. 33 3.4 Survival criteria after damage, all vessels.......................................... 33 Section 6 Piping systems...................................................................................... 35 1 General.............................................................................................. 35 1.1 Application..................................................................................... 35 1.2 Definitions......................................................................................35 1.3 Plans and particulars....................................................................... 36 1.4 Materials........................................................................................ 36 2 Design principles............................................................................... 37 2.1 General..........................................................................................37 2.2 Arrangements................................................................................. 37 2.3 Operation of valves......................................................................... 38 3 Pipes, pumps, valves, flexible hoses and detachable pipe connections...........................................................................................38 3.1 General..........................................................................................38 3.2 Pumps........................................................................................... 38 4 Manufacture, workmanship, inspection and testing........................... 38 4.1 General..........................................................................................38 5 Marking.............................................................................................. 39 5.1 General..........................................................................................39 6 Machinery piping systems..................................................................39 6.1 General..........................................................................................39 6.2 Seawater cooling systems................................................................ 39 6.3 Fresh water cooling systems............................................................ 39 6.4 Lubricating oil systems.................................................................... 40 6.5 Fuel oil systems............................................................................. 40 6.6 Air inlets for main and auxiliary engines............................................ 40 6.7 Exhaust systems.............................................................................40 6.8 Hydraulic systems........................................................................... 40 6.9 Machinery space ventilation............................................................. 41 7 Vessel piping system......................................................................... 41 7.1 General..........................................................................................41 7.2 Air, sounding and overflow pipes...................................................... 41 7.3 Main seawater system..................................................................... 42 7.4 Bilge systems................................................................................. 44 7.5 Drainage........................................................................................ 46 7.6 Oil pollution prevention................................................................... 46

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 6

Part 5 Chapter 13 Contents

3.2 Extent of damage for monohull vessels............................................. 32

Section 7 Machinery, propulsion and positioning.................................................. 47 1 General requirements........................................................................ 47 1.1 Application..................................................................................... 47 1.2 Documentation............................................................................... 47 2 Operational conditions....................................................................... 47 2.1 Operational conditions..................................................................... 47 3 Arrangement and system design....................................................... 48 3.1 Basic principles...............................................................................48 3.2 Machinery space arrangements.........................................................48 3.3 Redundancy................................................................................... 49 3.4 Arrangement of air intake................................................................ 49 4 Component specific requirements......................................................50 4.1 Propeller........................................................................................ 50 4.2 Shafting and vibration..................................................................... 50 4.3 Steering gear................................................................................. 50 4.4 Thrusters....................................................................................... 50 Section 8 Electric power generation and transfer................................................. 51 1 General requirements........................................................................ 51 1.1 Application..................................................................................... 51 1.2 Definitions......................................................................................51 1.3 Documentation............................................................................... 52 2 Design principles............................................................................... 52 2.1 Environmental conditions................................................................. 52 2.2 Earthing.........................................................................................52 2.3 Marking......................................................................................... 52 2.4 Indicator lights............................................................................... 52 3 System design................................................................................... 53 3.1 Supply systems.............................................................................. 53 3.2 D.C. voltage variations.................................................................... 54 3.3 Main source of electrical power........................................................ 54 3.4 Emergency source of electrical power................................................55 3.5 Casualty power distribution system................................................... 56 3.6 Distribution.................................................................................... 56 3.7 Shore connection............................................................................ 57 3.8 Choice of cable and wire types......................................................... 57 3.9 Control gear for motors and other consumers.................................... 58

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 7

Part 5 Chapter 13 Contents

7.7 Ballast systems.............................................................................. 46

4 Switchgear and control gear assemblies........................................... 58 4.1 Mechanical construction................................................................... 58 4.2 Remote operated switchboard.......................................................... 58 5 Rotating machinery............................................................................59 5.1 Motors........................................................................................... 59 6 Miscellaneous equipment................................................................... 59 6.1 Switchgear..................................................................................... 59 6.2 Galley equipment............................................................................59 6.3 Batteries........................................................................................ 59 7 Installation and testing..................................................................... 59 7.1 Principles....................................................................................... 59 7.2 Generators..................................................................................... 59 7.3 Switchboards.................................................................................. 60 7.4 Cables........................................................................................... 60 7.5 Screening and earthing of cables...................................................... 61 7.6 Marking of cables........................................................................... 61 7.7 Batteries........................................................................................ 61 7.8 Low intensity illumination................................................................ 61 7.9 Emergency lighting......................................................................... 62 8 Electric propulsion............................................................................. 63 8.1 General..........................................................................................63 8.2 Design principles.............................................................................63 8.3 System design................................................................................63 Section 9 Control and monitoring......................................................................... 64 1 General requirements........................................................................ 64 1.1 General..........................................................................................64 1.2 Application..................................................................................... 64 2 Documentation...................................................................................64 2.1 Requirements for documentation...................................................... 64 3 System design................................................................................... 64 3.1 General..........................................................................................64 3.2 Data communication links................................................................ 64 3.3 System independence......................................................................64 4 Component design and installation....................................................64 4.1 Enclosure....................................................................................... 65 4.2 Temperature................................................................................... 65 4.3 Electromagnetic interference............................................................ 65

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 8

Part 5 Chapter 13 Contents

3.10 Battery supplies............................................................................ 58

4.5 Sensors......................................................................................... 65 5 Alarm system.....................................................................................65 5.1 Alarm system in the accommodation.................................................65 6 Damage control system..................................................................... 66 6.1 General..........................................................................................66 7 Monitoring and control...................................................................... 66 7.1 General..........................................................................................66 8 Control systems................................................................................. 67 8.1 General..........................................................................................67 8.2 Steering control system...................................................................67 8.3 Water jet control system................................................................. 67 8.4 Stabiliser control system..................................................................67 Section 10 Fire safety........................................................................................... 68 1 General.............................................................................................. 68 1.1 General..........................................................................................68 2 Rule references and definitions......................................................... 68 2.1 Fire technical definitions.................................................................. 68 3 Documentation...................................................................................68 3.1 Documentation requirements............................................................68 4 Structure............................................................................................70 4.1 Structural integrity.......................................................................... 70 5 Fire control zones.............................................................................. 70 5.1 Fire control zones........................................................................... 70 6 Fire integrity of bulkheads and decks................................................70 6.1 Fire integrity of bulkheads and decks................................................ 70 7 Means of escape................................................................................ 71 7.1 Arrangement.................................................................................. 71 7.2 Emergency escape breathing devices................................................ 71 8 Ventilation systems........................................................................... 72 8.1 Requirements for ventilation system................................................. 72 9 Material requirements........................................................................72 9.1 Restricted use of combustible material.............................................. 72 10 Fire detection system...................................................................... 72 10.1 Areas to be protected....................................................................72 10.2 Requirements for systems.............................................................. 72 11 Fixed fire-extinguishing system.......................................................73 11.1 Fixed fire-extinguishing systems for machinery spaces....................... 73

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 9

Part 5 Chapter 13 Contents

4.4 Inclination...................................................................................... 65

11.3 Design considerations.................................................................... 73 11.4 Fixed extinguishing in service spaces...............................................73 12 Fire-extinguishing equipment.......................................................... 74 12.1 Portable fire extinguishers.............................................................. 74 12.2 Portable foam applicators outside machinery spaces.......................... 74 13 Fire pumps and fire main................................................................ 74 13.1 Capacity of fire pumps.................................................................. 74 13.2 Water distribution system.............................................................. 74 14 Firefighter’s outfit............................................................................75 14.1 Number and location..................................................................... 75 14.2 Personal equipment and breathing apparatus....................................75 15 Other spaces.................................................................................... 75 15.1 Storage rooms for explosives......................................................... 75 15.2 Spaces containing diving systems................................................... 75 15.3 Storage spaces for vehicles............................................................ 75 16 Helicopter facilities.......................................................................... 76 16.1 Helicopter facilities........................................................................ 76 17 Fire control plans.............................................................................76 17.1 Requirements................................................................................76 Section 11 Fire safety requirements for fibre-reinforced plastics (FRP) naval vessels.................................................................................................................. 77 1 General requirements........................................................................ 77 1.1 General..........................................................................................77 1.2 Rule references and definitions......................................................... 77 1.3 Requirements for documentation...................................................... 78 2 Structural fire protection, materials and arrangements..................... 78 2.1 Fire control zones........................................................................... 78 2.2 Structural fire protection..................................................................78 2.3 Material requirements......................................................................78 2.4 Arrangements................................................................................. 79 2.5 Means of escape.............................................................................79 3 Ventilation......................................................................................... 79 3.1 Ventilation zones and active smoke control........................................ 79 4 Fire detection system........................................................................ 80 4.1 Arrangement.................................................................................. 80 5 Fire extinguishing systems and hazardous spaces.............................81 5.1 Fixed fire extinguishing system for machinery spaces.......................... 81

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 10

Part 5 Chapter 13 Contents

11.2 Fixed local application fire extinguishing system................................73

6 Fire pumps, fire main and portable extinguishers..............................82 6.1 Fire pumps, fire main and fire hoses................................................. 82 6.2 Portable fire extinguishers................................................................83 7 Sprinkler system................................................................................83 7.1 Sprinkler system.............................................................................83 8 Firefighter’s outfit..............................................................................83 8.1 General..........................................................................................83 9 Additional fire protection (optional).................................................. 84 9.1 General..........................................................................................84 9.2 Accommodation.............................................................................. 84 9.3 Engine room.................................................................................. 84 Section 12 Safe evacuation of personnel.............................................................. 86 1 General.............................................................................................. 86 1.1 General..........................................................................................86 1.2 Definitions......................................................................................87 1.3 Exemptions.................................................................................... 87 1.4 Special requirements for class notation Naval support..........................88 1.5 Documentation requirements............................................................88 2 Communications.................................................................................88 2.1 Communication............................................................................... 88 2.2 Signalling equipment....................................................................... 89 3 Personal life-saving appliances..........................................................89 3.1 Lifebuoys....................................................................................... 89 3.2 Lifejackets......................................................................................89 3.3 Immersion and anti-exposure suits................................................... 90 4 Muster list, emergency instructions and manuals.............................. 90 4.1 General..........................................................................................90 5 Operating instructions....................................................................... 90 5.1 General..........................................................................................90 6 Survival craft stowage....................................................................... 91 6.1 General..........................................................................................91 7 Survival craft and rescue boat embarkation and recovery arrangements....................................................................................... 92 7.1 General..........................................................................................92 8 Line-throwing appliance.................................................................... 92 8.1 General..........................................................................................92 9 Operational readiness, maintenance and inspections........................ 92

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 11

Part 5 Chapter 13 Contents

5.2 Other fire hazardous spaces or equipment......................................... 81

9.2 Operational readiness...................................................................... 92 9.3 Maintenance................................................................................... 92 9.4 Servicing on inflatable liferafts, inflatable lifejackets and inflated rescue boats........................................................................................ 93 10 Survival craft and rescue boats....................................................... 94 10.1 Vessels with length less than 30 m................................................. 94 10.2 Vessels with length above 30 m......................................................94 11 Additional requirements for equipment........................................... 94 11.1 Liferafts....................................................................................... 94 11.2 Climbing nets............................................................................... 95 Section 13 Radiation hazards................................................................................96 1 General.............................................................................................. 96 1.1 Application..................................................................................... 96 2 Definitions..........................................................................................96 2.1 Terms............................................................................................ 96 3 Documentation...................................................................................97 3.1 Plans and particulars....................................................................... 97 4 Design principles............................................................................... 97 4.1 General..........................................................................................97 4.2 Prevention of auto ignition............................................................... 98 4.3 Prevention of personnel exposure..................................................... 98 5 Installation...................................................................................... 103 5.1 General........................................................................................ 103 5.2 Marking........................................................................................104 6 Testing............................................................................................. 105 6.1 Harbour acceptance tests (HAT) for the vessel.................................. 105 Section 14 Electromagnetic compatibility (EMC)................................................. 106 1 General............................................................................................ 106 1.1 Application................................................................................... 106 1.2 Principles......................................................................................106 2 Definitions........................................................................................107 2.1 Terms.......................................................................................... 107 3 Documentation.................................................................................107 3.1 Plans and particulars..................................................................... 107 4 Design principles............................................................................. 108 4.1 General........................................................................................ 108 4.2 Lightning protection.......................................................................108

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 12

Part 5 Chapter 13 Contents

9.1 General..........................................................................................92

5 Installation...................................................................................... 109 5.1 General........................................................................................ 109 5.2 Shielding...................................................................................... 109 5.3 Bonding and grounding..................................................................109 5.4 Cabling........................................................................................ 110 5.5 Filtering....................................................................................... 111 5.6 Lightning protection.......................................................................111 5.7 Electrostatic discharge................................................................... 111 5.8 Marking........................................................................................111 6 Testing............................................................................................. 112 6.1 General........................................................................................ 112 6.2 Factory acceptance tests (FAT) for equipment................................... 112 6.3 Harbour acceptance tests (HAT) for the vessel.................................. 112 6.4 Sea acceptance tests (SAT) for the vessel........................................ 112 Section 15 Storage rooms for explosives............................................................ 113 1 General............................................................................................ 113 1.1 Application................................................................................... 113 1.2 Definitions.................................................................................... 113 2 Basic requirements.......................................................................... 113 2.1 General........................................................................................ 113 2.2 Plans and particulars to be submitted.............................................. 113 3 Arrangements.................................................................................. 113 3.1 General........................................................................................ 113 4 Structure.......................................................................................... 114 4.1 Structural requirements................................................................. 114 5 Fire safety........................................................................................115 5.1 General........................................................................................ 115 5.2 Structural fire protection................................................................ 115 5.3 System fire safety.........................................................................115 5.4 Fire protection.............................................................................. 115 6 Radiation hazards............................................................................ 116 6.1 Electromagnetic radiation protection................................................ 116 7 Signboards....................................................................................... 116 7.1 General........................................................................................ 116

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 13

Part 5 Chapter 13 Contents

4.3 Electrostatic discharge................................................................... 108

Symbols For symbols not defined in this section, refer to Pt.3 Ch.1 Sec.4 [2].

1 Introduction 1.1 General 1.1.1 These rules define acceptance criteria for design, construction, survey and testing of naval surface vessels, their machinery installation, systems and equipment, applicable to the newbuilding and operational phase (military systems are excluded). 1.1.2 By assigning class to a naval surface vessel it shall be understood that the navy will utilise the Society’s quality assurance system for the design, fabrication and operation of the vessel (military systems excluded). The system will in no way replace the navy’s responsibility towards national authorities and international maritime conventions.

1.2 International codes and regulations 1.2.1 International codes and conventions are covered to the extent specified in the rule text. On request, the Society may, in addition, verify that specific international codes and conventions are complied with. 1.2.2 The rules under this chapter are based upon a safety regime administered by a national naval administration. Guidance note: A naval administration is the governmental body of the naval flag being responsible for HSE (Health, Safety and Environmental) aspects on a naval vessels of that flag. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.3 Application 1.3.1 The rules in this chapter will generally apply to ships of war and troopships. The requirements shall be regarded as supplementary to those given for assignment of main class for Ships. 1.3.2 The rules in this chapter do not apply to military systems unless as specifically defined in the following sections. Guidance note: Military systems are defined as: —

weapon systems

—

sensor systems

—

C I systems (Command, Control, Communication and Information systems.

3

---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.3.3 Military systems that influence the vessel and vessel systems shall be identified. Required support to military systems from vessel and vessels systems shall be specified. Guidance note: Support requirements to military systems may typically be: —

foundation loads

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 14

Part 5 Chapter 13 Section 1

SECTION 1 GENERAL

power supply

—

water supply

—

heating, ventilation and air conditioning. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.3.4 Conditions regarding the use of the vessel, which were established or presumed at the time of class assignment, shall be presented in a design brief describing the intended operational use of the vessel. (See [4.3]).

2 Class notations 2.1 Ship type notations 2.1.1 Vessels built in compliance with the requirements as specified in Table 1 will be assigned the class notations as follows: Table 1 Ship type notations Design requirements, rule reference

Class notation

Description

Naval

naval flagged vessels and vessels administered by a national naval administration

Pt.2, 3,4 and Pt.5 Ch.13

2.2 Additional notations 2.2.1 Naval support Vessels built in compliance with the requirements as specified in Table 2 will be assigned the class notation Naval support, with the relevant qualifiers in (...), e.g. Naval support (Hull, System, SAM) Table 2 Additional notations Notation

Qualifier

Naval support

Description None

vessel approved and operated under naval regime

Hull

additional naval requirements for arrangements and hull strength

Sec.2, Sec.3andSec.4

Stab

naval requirements for stability

Sec.5

additional naval requirements for piping, machinery, electrical and control systems

Sec.6, Sec.7, Sec.8 and Sec.9

additional naval requirements for fire safety

Sec.10 or Sec.11

naval requirements for safe evacuation

Sec.12

naval requirements for radiation hazards

Sec.13

EMC

naval requirements for electromagnetic compatibility

Sec.14

SAM

naval requirements for storage rooms for ammunition

Sec.15

System

Naval support

Application

Fire EVAC RADHAZ

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

NA

Page 15

Part 5 Chapter 13 Section 1

—

2.2.3 Other additional notations The following additional notations, as specified in Table 3, are applicable to Naval and Naval support vessels: Table 3 Additional notations Notation

Description

Application

FIRENAV

additional naval requirements for fire protection

Sec.11 [9]

Navdist

in case of deviations from the rules and given class notation and/or service restriction

[5]

Naval surface vessel having special equipment and or systems found to satisfy relevant requirements in Pt.6, will be given corresponding additional class notations if so desired by the navy.

3 Definitions 3.1 Terms Table 4 Definitions Terms

Definition

FMEA

failure mode and effect analysis

HAZOP

hazard operation

Area classification

is a way of identifying special sections on the vessel with special protective requirements

NBC

nuclear, biological and chemical threats to a naval surface vessel

3

C I

command, control, communication and information

ARM

availability, reliability and maintainability - usually the design objective for commercial ships

VR

vulnerability reduction - usually the design objective for warships

Survivability

capability of a warship to float, to move and to fight - achieved by vulnerability and susceptibility reduction measures

Susceptibility measures

design aspects to prevent detection and weapon attraction, to decoy and avoid the attacking weapon and to destroy the attacking weapon - related to signature reduction

Vulnerability measures

design aspects to resist weapon effects, minimise damage and maximise recoverability related to weapon effect reduction

Naval threat

the threat to a naval vessel: — accidents — terrorist attack — conventional war — nuclear war

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 16

Part 5 Chapter 13 Section 1

2.2.2 Classification of hull only The notation 1A (Hull) will be assigned to vessels with class notation Naval or Naval support with hull and equipment in compliance with the rule requirements as given in Pt.2 and Pt.3 Ch.1 to Pt.3 Ch.14in the Rules for classification of ships.

Definition

Military object

object installed on the vessel that is not needed for safe operation of the vessel in peacetime

STANAG

standardised NATO agreement

AQAP

allied quality assurance publication

4 Classification of newbuildings 4.1 General requirements for documentation 4.1.1 Additional plans and particulars that normally shall be submitted when the additional class notation given in [2] are applied for, are given in Sec.2 to Sec.14. The documentation shall show clearly that the rule requirements are fulfilled. 4.1.2 Other plans, specifications or information may be required depending on the arrangement and the equipment used on each separate vessel. 4.1.3 The following plans shall be submitted for approval: — structural support of main weapon(s) and weapon system(s) — structural support of main sensor(s) and sensor system(s). 4.1.4 The following plans and documentation shall be submitted for information as far as applicable: — arrangement and particulars of main weapon(s) and weapon system(s), including loads acting on the supporting structure — arrangement and particulars of main sensor(s) and sensor system(s), including loads acting on the supporting structure

4.2 Classification basis 4.2.1 Documents describing the intended operational characteristics of the vessel shall be submitted to the Society for information. Guidance note: In addition to data specified for main class requirements, operational characteristics should as appropriate include items such as: —

service speed, top speed

—

ballasting requirements

—

cargo capacity

—

sea-state limitations. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4.2.2 Conditions regarding the use of the vessel, which were established or presumed at the time of class assignment, shall be presented in a design brief report describing the intended operational use of the vessel.

4.3 Yard qualification 4.3.1 The yard and its main subcontractors shall operate a certified quality assurance system corresponding to AQAP series, ISO 9000 series or equivalent and applicable for their work task.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 17

Part 5 Chapter 13 Section 1

Terms

4.4.1 The yard shall arrange for regular quality meetings discussing relevant issues and building progress. All relevant parties shall attend the meetings.

4.5 Certification of components and equipment 4.5.1 Combat and other naval installations that shall be used in the vessel and that are not certified by the Society shall be identified stating their structural and system demand as covered by these rules.

4.6 Confidentiality 4.6.1 Personnel assigned to supervise compliance with the rules will be subjected to confidentiality and security requirements set forward by the ordering navy. 4.6.2 The Society will store files and records in accordance with confidentiality and security requirement agreed with the ordering navy. 4.6.3 Communication between yard and the Society shall comply with relevant security procedures identified by the ordering navy.

4.7 Area identification 4.7.1 The vessel shall be classified into operational areas identifying protective measures and or operational limitations allowed in these areas. The areas shall be described identifying special measures taken to accommodate the restrictions placed on the area.

5 Deviations from the rules 5.1 General 5.1.1 The navy may decide that a naval vessel shall deviate from the requirements put forward in the rules. 5.1.2 In case of deviations from the rules and given class notation and or service restriction, the class notation on the certificate shall have the following letters assigned in brackets: (navdist) - meaning naval distinction. 5.1.3 Any deviations from the requirements for the assigned class notation shall be addressed in the class certificate and explained in the “Appendix to the classification certificate”. Guidance note: Deviations should be subject to special consideration, and evaluations made in terms of technical scope and responsibilities. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 18

Part 5 Chapter 13 Section 1

4.4 Working relations

1 Deck arrangements 1.1 Deck definitions 1.1.1 1.deck is the uppermost deck extending completely and continuously from stem to stern. 2.deck, 3.deck etc. are respectively the first, second, etc. deck below 1.deck. 01 deck, 02 deck, etc. are respectively the first, the second, etc. deck above 1.deck. 1.1.2 Damage control deck is the deck providing the following facilities: 1) 2) 3) 4) 5)

good access throughout the ship horizontally and vertically ready access to emergency stops for equipment in compartments below ready access to controls for fire pumps, fixed fire fighting systems and flooding control systems (like bilge ejectors) ready access to controls to limit the spread of smoke throughout the ship damage control stations, providing good weather protection for equipment stored and personnel.

1.2 Rescue area Naval vessel may be arranged with a permanent deck area applicable to rescue persons from the sea. A rescue area shall be well protected from propeller, rudder or other protrusions from the hull, and visibility to the area from the wheelhouse shall be arranged for, i.e. by video camera if necessary. Separate rescue searchlights shall cover the deck rescue area and the corresponding side of the vessel.

1.3 Guard-rails and handholds For safe working on deck, adequate guard-rails and handholds shall be arranged were it is considered necessary for personnel safety. Guard-rail around the anchoring position is required. Guard-rails are in general to have a height of minimum 1 000 mm above deck. For decks not intended for crew access at sea, it may be accepted to have an arrangement with portable railing for in harbour use.

2 Watertight compartments 2.1 Watertight boundaries 2.1.1 The primary functions of the watertight boundaries are: — — — — —

to to to to to

limit the extent of flooding after accidental or action damage form the limits of the NBC-zones support the hull plating and structure and maintain the external hull form help resist hull torsional loads support the internal decks and equipment

2.1.2 Access and ventilation openings in watertight boundaries shall have watertight closing appliances of approved type. 2.1.3 Access and ventilation openings shall be kept closed and monitored in the damage control centre machinery control room in accordance with established watertight and gas tight conditions in force.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 19

Part 5 Chapter 13 Section 2

SECTION 2 ARRANGEMENTS

3.1 General principle 3.1.1 To minimise the consequences of damage, fire and NBC contamination, a vessel shall be divided into zones in order to: — avoid catastrophic loss of an important system capability by a single incident — restrict the spread of fire, smoke, flooding, blast and fragments — avoid loss of primary functions due to damage, which is remote from the main components of that system. 3.1.2 Zones shall be sufficiently self-contained to operate for periods with the zone boundary closed.

3.2 Fire control zones Fire control zones are zones with boundaries (e.g. decks, bulkheads) which are fire insulated to reduce spreading of fire to adjacent zones and which are fitted with facilities to prevent the spread of smoke to adjacent zones. Boundaries for fire control zones shall coincide with watertight divisions. Within a fire control zone a further watertight subdivision is possible.

3.3 Damage control zones Damage control zones are zones, which are allocated to specific damage control teams for initial fire fighting, flooding control and repair activities. Damage control zone boundaries coincide with watertight and fire resistant subdivisions of the ship. Inside a damage control zone there shall be at least one damage control station.

3.4 Gastight division A gastight division is provided by gastight bulkheads and decks forming a gastight compartment to avoid ingress of NBC-agents to a zone or citadel.

3.5 Hazardous areas Hazardous areas are all areas in which explosives and flammable materials are stored or transported as a part of normal operation.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 20

Part 5 Chapter 13 Section 2

3 Zones

1 General requirements 1.1 General 1.1.1 A naval vessel shall comply with the design principles and design loads applicable for main class with the modifications specified in this section.

2 Operational loads 2.1 General 2.1.1 Loads caused by gas pressure and or heat during launching of weapon systems shall be considered. The manufacturer shall specify the loads. 2.1.2 Specified ice build-up shall be evaluated as a loading condition in connection with determination of hull global strength and stability calculations.

3 Accidental loads 3.1 Local damage 3.1.1 Frames and decks shall be checked for extreme loading due to water filling due to specified battle type damages. All relevant combinations of water filling shall be considered.

3.2 Global damage 3.2.1 If a global hull damage case has been specified for the vessel, the hull girder loads in damaged conditions shall be calculated by direct load calculations.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 21

Part 5 Chapter 13 Section 3

SECTION 3 DESIGN LOADS

1 General requirements 1.1 Structural strength Naval vessels made of steel shall comply with the strength requirements given for main class in Pt.3, with the modifications and additions specified in this section.

2 Structural arrangement 2.1 Main structure 2.1.1 Special attention shall be paid to ensure continuity of main structural elements. 2.1.2 At discontinuities of the longitudinal structure, e.g. where sonar domes are fitted, the longitudinal as well as the transverse strength shall be maintained, e.g. by fitting bottom girders and or heavy frames. 2.1.3 Design of local details shall seek to keep stress concentrations to a minimum. 2.1.4 Heavy beams or deck girders to absorb forces shall be preferred to pillars carried directly to the bottom structure. Such pillars may transfer shocks from underwater explosions, causing detrimental effect to the equipment. 2.1.5 Doublers are not allowed as support for heavy equipment. 2.1.6 Shock sensitive equipment shall not be installed directly on pillars. 2.1.7 Pillars provided primarily to support heavy equipment shall be treated as an extension of the foundation and designed accordingly. 2.1.8 Doublers are not allowed as support for pillars.

2.2 Bulkheads 2.2.1 When air tightness only is required for the bulkhead considered, scantlings shall be designed for 2 2 times overpressure or 2 kN/m whichever is highest.

2.3 Mast for support of sensors and sensor’s systems 2.3.1 Static strength calculations shall be performed for mast supporting sensors and sensor systems.

3 Local strength 3.1 Minimum thickness The requirements for minimum thickness may be disregardedon a case by case basis. As a minimum the following should be evaluated and documented if the requirements for minimum thickness shall be omitted: — possibility for dimensioning of structure based on known loads

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 22

Part 5 Chapter 13 Section 4

SECTION 4 STRUCTURAL STRENGTH

3.2 Local structure 3.2.1 The strength of structure exposed to loads caused by the firing of weapons shall be considered. The calculation shall take into account the exposed area, load response and duration. 3.2.2 Armament foundations shall be designed for the following loads: — static loads — reaction loads — pressure and blast and heat during firing of weapons. 3.2.3 If specified, structure shall be designed locally with respect to ice build-up.

3.3 Damage of local structure 3.3.1 Frames, bulkheads and decks shall be designed for extreme loading occurring when the vessel is damaged, i.e. with internal spaces filled with water. If the vessel has watertight tweendeck(s) the damage shall be assumed to the above each deck as one loading condition and below same as another. The water head shall be taken to the bulkhead deck in both cases. 3.3.2 The structure of storage rooms for explosives shall be designed for flooding, i.e. with the complete space filled with water, see Sec.15.

4 Global strength 4.1 General 4.1.1 Global strength FE analysis shall be made for vessels with: — unusual hull form and construction — specified global damage. For general criteria for global strength FE analysis, reference is made to Pt.3 Ch.7 Sec.2.

5 Weld connections 5.1 Application of fillet welds Double continuous fillet welds only shall be applied in structures subjected to significant dynamic loading, in foundation joints to bottom and 1. deck, and in connections where the supporting member is subjected to large bending moments or shear forces.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 23

Part 5 Chapter 13 Section 4

— deformation of the structure — fabrication aspects — practical aspects such as local impact and load effects not explicitly covered by the rules.

6.1 Modelling of hull structure 6.1.1 For naval vessels the deformations in certain areas are of major importance with respect to the operation of the vessel. Some of these areas are not relevant for the global strength, but shall be included in the global model due to deformation. Thus, attention shall be paid during modelling with respect to superstructure and mast-houses. For special equipment such as main weapons, main sensors and masts, extra finite element models may have to be prepared if necessary.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 24

Part 5 Chapter 13 Section 4

6 Direct strength calculations

1 General 1.1 Applicability 1.1.1 Vessels with class notation Naval or Naval support(Stab) shall comply with the requirements for stability, watertight and weathertight integrity applicable for main class with the modifications specified in this section.

1.2 Plans and calculations 1.2.1 A report on damage stability calculations and an internal watertight integrity plan are required. The calculations shall demonstrate that the vessel for the prescribed loading conditions meet the intact and the damage stability requirements. 1.2.2 The stability manual shall contain documentation of the loading conditions specified in [2.1.1]. Operational recommendations, such as instructions on fuel oil consumption and ballasting and restrictions on use of rolling tanks shall be clearly stated in the stability manual, as far as applicable. 1.2.3 It is recommended to develop maximum allowable VCG curves based on the criteria in [2] and [3]. It is recommended to include separate curves covering conditions with ice, if applicable.

2 Intact stability requirements 2.1 Loading conditions 2.1.1 Compliance with the intact and damage stability criteria shall be demonstrated for the loading conditions shown in Table 1, and for any conditions of loading in the operating range between full load and minimum operating condition that will give poorer stability. In addition a loading condition with ice load according to [2.3.3] shall be included, if applicable. Guidance note 1: For vessels having an operational profile which implies that the loading conditions deviate from those indicated in Table 1, alternative conditions may be accepted as the basis for the approval. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: Excessive metacentric heights should be avoided in particular for conventional monohull vessels, as it will result in rapid and violent motions. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.2 The harbour condition corresponds to the minimum operating condition, as found in Table 1, except that all tanks are empty. This is a non-operating condition to which the stability criteria does not apply. However, the metacentric height shall be calculated. If this is negative, the harbour condition shall be avoided by ballasting. The harbour condition and if applicable, the ballasting instructions, shall be stated in the stability manual.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 25

Part 5 Chapter 13 Section 5

SECTION 5 STABILITY, WATERTIGHT AND WEATHERTIGHT INTEGRITY

Load item

Full load condition

Minimum operating condition

vessel’s complement

all persons with effects onboard

all persons with effects onboard

ammunition

magazines and ready service stowages 1/3 of full load ammunition with maximum quantities in filled to maximum capacity ready service stowage and remainder in magazines

mines

maximum number onboard

maximum number onboard

missiles

maximum number onboard

least favourable quantity and disposition is assumed

torpedoes

maximum number onboard

least favourable quantity and disposition is assumed

aircraft

all onboard

all onboard

provisions

stores filled

1/3 of full load

general stores

all onboard

2/3 of full load

lubrication oil

95% of maximum capacity

2/3 of full load

fuel oil

95% of maximum capacity

least favourable realistic disposition (normally 5%)

aviation fuel

95% of maximum capacity

1/2 of full load

feed water

95% of maximum capacity

1/2 of full load and least favourable disposition

fresh water

95% of maximum capacity

1/2 of full load and least favourable disposition

1)

bilge water tanks

empty

2)

trim and ballast tanks

empty

2)

roll damping tanks

filled to operating capacity

filled to operating capacity

overflow tank

1/2 full

empty

septic tanks

empty

empty

empty

2)

empty, unless full tanks are needed in order to obtain a 2) favourable trim and/or sufficient stability

1)

The centre of gravity of the vessel’s complement with effects is taken to be at deck level, 1. deck, mass 120 kg/ person.

2)

Design conditions may be used.

2.2 Calculation of stability 2.2.1 First and second tier superstructure and first tier deckhouses may be taken into account in the stability calculations provided: — enclosing bulkheads are of efficient construction — access openings if any, and other openings in sides or ends of the superstructure, or deckhouses are fitted with efficient weathertight means of closing.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 26

Part 5 Chapter 13 Section 5

Table 1 Loading conditions for intact and damage stability criteria

Part 5 Chapter 13 Section 5

2.3 Calculation of effects from external loads 2.3.1 The heeling arm due to wind, in m, shall be obtained from the formula:

where:

Ai ℓi Δ θ Vi n

= projected area of i

th

portion, in m

2

= lever arm from half draught to centre of wind pressure on i

th

layer, in m

= displacement, in t = angle of heel in deg = wind velocity in knots at centre of wind pressure on i

th

layer

= number of layers into which the area is divided

The following minimum wind velocities shall be applied: For vessels without service area restriction and service area restriction R0 or R1: 80 knots For vessels with service area restriction R2 or R3 that will be recalled to harbour or protected waters if winds over Beaufort force 8 are expected: 60 knots. This shall be stated as a limitation in the stability manual. The nominal velocities V10 in knots, are given for a height of 10 m above the waterline. The velocity to be applied at height z in m above the waterline shall be derived from the following formula:

For calculation of the total heeling arm, the projected area is divided into layers of 1 to 2 m thickness depending on the size of the vessel. The centre of wind pressure for each layer shall be taken to be at the centroid of the particular layer. Reasonable account shall be taken of miscellaneous items contributing to the projected area. Guidance note 1: Horizontal surfaces, such as a helicopter deck, may contribute significantly to the wind heeling arm as the vessel heels. Therefore such surfaces should be included in the calculations. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 1: For ships with smooth surfaces (e.g. stealth designs) where the drag coefficient may be considered to be less than for a conventional ship, a reduction in the wind heeling arm may be taken into account, but not by more than 10%. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 27

2.3.3 Stability during conditions with beam wind combined with topside icing The weight and distribution of accumulated ice shall be assumed as follows: 2

— mass of accumulated ice per m of all exposed weather decks, platforms and front bulkheads of 2 superstructure and deckhouse shall be assumed not less than 30 kg/m 2 — mass of accumulated ice per m on both sides of projected lateral area of the portion of the vessel above 2 the water plane shall be assumed not less than 15 kg/m — mass of ice accumulated on rails, spars (except masts which shall be included above), rigging and small miscellaneous objects shall be taken into account by increasing the total projected lateral area above by 5% and the total static moment of this area by 10% — the location of centre of gravity of the accumulated ice shall be determined in accordance with the actual location and assumed distribution given above. The effect of beam wind shall be considered as given in [2.3.1]. The wind velocities to be applied are as follows: — For vessels without service area restriction and service area restriction R0 or R1: 60 knots — For vessels with service area restriction R2 or R3 that will be recalled to harbour or protected waters if winds over Beaufort force 8 are expected: 50 knots. This shall be stated as a limitation in the stability manual. 2.3.4 For vessels equipped with cranes the heeling arm due to lifting masses over the side, in m, shall be calculated by the formula:

where:

W b Δ θ

= mass of lift, in t = transverse distance from centre line of vessel to end of boom, in m = displacement including mass of lift, in t = angle of heel, in deg.

2.3.5 The heeling arm due to the centrifugal force acting on the vessel during a turn, in m, shall be obtained from the formula: (1) where:

V Vmax g t R L

= linear velocity of vessel in turn, in m/s, not to be taken less than 0.65 Vmax

θ

= angle of heel, in deg.

= maximum speed, in m/s = acceleration due to gravity, in m/s

2

= distance between vessel’s centre of gravity and half draught, with vessel upright, in m = radius of turning circle, in m, not to be taken greater than 2.5 L = overall length of the underwater watertight envelope of the rigid hull excluding appendages, in m, at or below the waterline ([2.2.1]) in the displacement mode with no lift or propulsion machinery

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 28

Part 5 Chapter 13 Section 5

2.3.2 Vessels that will not be allowed to operate in conditions where icing may occur need not to comply with [2.3.3]. This shall be stated as a limitation in the stability manual.

In those cases where the vessel’s arrangement makes the above anticipated values unreasonable, alternative values documented by model tests and full scale tests may be applied. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.3.6 The heeling due to concentration of personnel at 1.deck on one side of the vessel shall be considered as follows: The total number of persons onboard is assumed located at 1.deck. For the purpose of calculation, the mass of each crew member shall be taken as 80 kg and the centre of gravity 1.0 m above deck. The heeling arm, in m, shall be calculated by the formula:

where:

W S

= mass of total number of persons

Δ θ

= displacement, in t

= distance, in m, from the centre line of the vessel to the centre of gravity of the crew. It is assumed 2 that the total complement have moved as far as possible to one side, each person occupying 0.2 m of deck space = angle of heel, in deg.

2.4 Intact stability for monohull vessel 2.4.1 When the vessel is subject to wind and icing resulting in a heeling arm as described in [2.3.1] and [2.3.3], the criteria as given in [2.4.2] shall be complied with. 2.4.2 These stability conditions assume the vessel to be heeled over by the force of the wind alone until equilibrium occurs and then roll 25° from this point to windward. The stability is considered satisfactory if: a) b) c) d) e)

The heeling arm at the intersection of the righting and heeling arm curve, point C in Figure 1, is not greater than six tenths of the maximum righting arm. See Figure 1. The angle of heel corresponding to point C in Figure 1 does not exceed 15°. The area A1 indicated in Figure 1 is not less than 1.4 A2 where the area A2 extends 25° to windward from point C. The area A1 is limited to the angle at which downflooding occur. The range of the GZ curve is at least 70°. The GZ-curve is positive over the complete range. Guidance note: The GZ curve should be terminated at the downflooding angle. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.4.3 When the vessel is subject to a heeling moment as described in [2.3.4] to [2.3.6] as far as applicable, the criteria in [2.4.4] shall be complied with. 2.4.4 The stability is considered satisfactory if: a) b)

The heeling arm at the intersection of the righting and heeling arm, point C in Figure 2, is not greater than six tenths of the maximum righting arm. See Figure 2. The angle of heel corresponding to point C in Figure 2 does not exceed 15°. This angle may however be increased up to 20° if all safety systems and machinery are designed for operation at such angles.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 29

Part 5 Chapter 13 Section 5

Guidance note:

RIGHTINGARMSANDHEELINGARMS.m

d)

The reserve dynamic stability (shaded area in Figure 2) is not less than four tenths of the total area under the righting arm curve. The GZ-curve is positive over the complete range.

1.2

Curve A = INTACT RIGHTING ARM CURVE

0.9

Curve B = WIND HEELING ARM CURVE

0.6 25°

C

CURVE A

AREA A1 140% A2 NOT LESS THAN

NOT MORE AREA

A2

0

10

20

30

THAN 0.6 R.A. MAX.

40

50

60

70

80

CURVE B

90

T ANGLE OF INCLINATION -DEGREES MAXIMUM RIGHTING ARM

Figure 1 Stability criteria

Figure 2 Stability criteria Guidance note 1: The GZ curve should be terminated at the downflooding angle. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: The vessel’s behaviour in following seas, may be studied by carrying out stability calculations at an assumed wave, with shape, height and length as given below: The trochoidal wave applied should have the following characteristics:

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 30

Part 5 Chapter 13 Section 5

c)

1)

The vessel should comply with the requirements given in [2.4.2] with a righting arm curve calculated as the average of the curves obtained assuming a trochoidal wave as described above assuming wave crest amidships and wave trough amidships.

2)

The vessel should, when assuming: a)

the wave crest amidships

b)

the wave trough amidships

c)

and wave characteristics as described above, comply with the following criteria: —

the righting arm is positive over a range of at least 10°

—

between 0 and 45° inclination

—

the maximum righting arm is at least 0.05 m.

It is not necessarily the conditions with wave crest amidships that will provide the weakest GZ-curve. This depends on the shape of the vessel and will occur at the longitudinal section with the largest cross-section area. For vessels with an unusual shape it may be required to document the stability characteristics with model tests. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.5 Intact stability for multihull vessels 2.5.1 The same requirements shall be applied as for monohull vessels.

3 Internal watertight integrity 3.1 Watertight subdivision 3.1.1 Pipes, electrical cables and remote control extensions penetrating watertight and gastight bulkheads and decks, shall be arranged with penetration fittings with the same degree of tightness as the actual bulkhead. 3.1.2 Main watertight bulkheads shall be installed and located to fulfil stability and buoyancy requirements according to [3]. Sill heights shall be at least 230 mm. Access openings leading to tanks, cofferdams and voids shall be fitted with watertight manhole covers. 3.1.3 All pipes piercing the collision bulkhead shall be fitted with screw down valves capable of being operated from above the damage control deck. 3.1.4 No doors, manholes (other than manholes leading to tanks), access openings, or ventilation ducts are permitted in main transverse watertight bulkheads below the damage control deck. The number of openings above the damage control deck shall be reduced to the minimum compatible with the design and proper working of the vessel. Doors shall have the same closing appliances as in Ch.12 Sec.3 [3]. Where pipes, scuppers, ventilation ducts and electric cables are carried through watertight subdivision bulkheads, arrangement shall be made to ensure the integrity of the watertightness of the bulkheads. Valves and cocks not forming part of a piping system shall not be permitted in watertight subdivision bulkheads below the damage control deck. Lead, plastics or other heat sensitive materials shall not be used in systems other than electric systems, which penetrate watertight subdivision bulkheads, where deterioration of such systems in the event of fire would impair the watertight integrity of the bulkheads.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 31

Part 5 Chapter 13 Section 5

Wave length: λ (in meter) equal to the length of vessel.

3.1.6 As a consequence of [3.1.5], double bottom or side tanks shall be divided in line with main transverse bulkheads, however, a total misalignment of maximum 1.0 m is permissible for one-compartment vessels. 3.1.7 Arrangement of cross-flooding ducts Where it is necessary to correct large angles of heel, cross-flooding may be arranged. In that case, the following requirements shall be satisfied: — [3.4.3] shall be complied with — Cross-connecting ducts or pipes shall be as large as possible to allow cross flooding to take place in shortest possible time. The time needed for equalisation shall not exceed 15 minutes, so that crossconnected compartments can be virtually treated as one.

3.2 Extent of damage for monohull vessels 3.2.1 The damage is assumed to extend vertically without any limit. If damage of a lesser extent results in a more severe condition, such lesser extent shall be assumed (e.g. intact double bottom). 3.2.2 The transverse penetration of damage is assumed to reach to the centre line of the vessel, but leaving any centre line bulkhead intact. If damage of a lesser extent results in a more severe condition, such lesser extent shall be assumed. 3.2.3 The longitudinal extent of damage is determined by the following minimum requirements. a)

Vessels with L ≤ 30 m These vessels shall be capable of withstanding flooding of any single main compartment, i.e. onecompartment vessels. Adjacent main transverse bulkheads shall be spaced at least (2.0 + 0.03 L) m apart to be considered effective. Where main transverse bulkheads are spaced at lesser distance, one or more of these bulkheads shall be assumed as non-existent.

b)

The longitudinal extent of damage in way of any such compartment is assumed to be equal to the length of that compartment less 1.0 m. Vessels with 30 m < L ≤ 90 m The longitudinal extent of damage is given by ℓd = 0.15 L – 2.6 m

c)

At least 2 adjacent main compartments shall be considered flooded. The vessel shall be capable of withstanding flooding wherever the damage is located. Vessels with L > 90 m The longitudinal extent of damage shall be 15 percent of the vessel’s length or 21 m whichever is less. The vessel shall be capable of withstanding flooding wherever the damage is located. L = overall length of the underwater watertight envelope of the rigid hull excluding appendages, at or below the waterline in full load condition, in the displacement mode with no lift or propulsion machinery.

3.2.4 The permeability of flooded compartments shall be assumed as given in Table 2.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 32

Part 5 Chapter 13 Section 5

3.1.5 Steps or recesses in main transverse bulkheads shall be avoided. However, if there are steps or recesses in transverse bulkheads bounding floodable compartments, only a total longitudinal depth of maximum 1.0 m is permissible for one-compartment vessels. See [3.2.3].

Compartments

Permeabilities

machinery spaces

0.85

intended for liquids

0 or 0.95

other compartments

1)

0.95

stores

0.6 2)

computed permeabilities 1)

Whichever results in the more sever requirements.

2)

If computed values of actual permeabilities are found to deviate substantially from the values given above, these computed values may be used. In this case curves showing the actual permeability as a function of the depth of the vessel for each compartment shall be submitted for approval.

3.2.5 The flooding of the storage rooms for explosives (see Sec.15) shall be documented.

3.3 Extent of damage for multihull vessels 3.3.1 The extent of damage is the same as for monohull vessels.

3.4 Survival criteria after damage, all vessels 3.4.1 Restrictions to limit flooding: a) b) c) d) e)

The final waterline after flooding, taking into account sinkage, heel, and trim shall be at least 0.30 m below the lower edge of any opening through which progressive flooding may take place. Openings, the lower edge of which shall not be submerged, include such as air pipes and ventilators, with weathertight closing, and weathertight hatches and doors. Openings, which may be submerged, include manholes, watertight hatches, watertight doors, and side scuttles of the non-opening type. If pipes, ducts or tunnels are situated within the assumed extent of penetration of damage as defined in [3.2], arrangements shall be made so that flooding cannot thereby extend beyond the limits assumed for the calculation of the damaged condition in question. No unprotected openings shall be located within a distance of 1.5 m measured from the equilibrium waterline.

3.4.2 The angle of heel (Point C in Figure 3) shall not exceed 15° in the final condition of equilibrium. When the damaged vessel is subject to a wind force calculated as outlined in [2.3.1], assuming a nominal wind speed of 40 knots, the following criteria shall be met: The available dynamic stability beyond point D in Figure 3 up to the angle θ1, i.e. the shaded area shall not be less than 0.025 mrad. The angle θ1 shall be taken as 45° or the angle at which progressive flooding (submersion of unprotected opening) would occur, whichever is less.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 33

Part 5 Chapter 13 Section 5

Table 2 Permeabilities

Part 5 Chapter 13 Section 5

0.5

θ1

RIGHTINGARMANDHEELINGARM.M

0.3

0.4

0.2 - 0.1

CU

CURVEB

10

RV

EA

D

C

20

30

40

50

θ - ANGLE OF INCLINATION, DEG

- 0.3 0.1 - 0.2

Figure 3 Stability criteria for flooded condition - 0.4

For vessels with service area restriction R2 and R3 a nominal wind speed of 30 knots may be applied. 3.4.3 The stability in the intermediate stages of flooding is considered satisfactory if: — the angle of heel does not exceed 20° — all openings through which progressive flooding of assumed intact spaces may occur, are above any intermediate damaged waterline — the residual area requirements in excess of the wind heeling arm are as in [3.4.2].

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 34

1 General 1.1 Application 1.1.1 Vessels with class notation Naval or Naval support(System) shall comply with the requirements for piping systems applicable for main class with the modifications specified in this section. 1.1.2 Naval vessels with an overall length L (as defined in Sec.1 [2.1.2]) of more than 50 m shall in general comply with the requirements in the rules for classification of ships, Pt.4 Ch.1 and Pt.4 Ch.6, with the additional requirements specified in this section. Naval vessels with L less than 50 m shall in general comply with the requirements in the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.6 and with the additional requirements specified in this section. 1.1.3 Classes of piping systems are specified in the rules for classification of ships, Pt.4 Ch.6 Sec.1 Table 1.

1.2 Definitions 1.2.1 Active components in this section is any component transforming energy e.g. pumps, compressors, fans, electric motors and generators, combustion engines and turbines. Heat exchangers and boilers are normally not considered as active components. 1.2.2 Main functions in this section are defined in the rules for classification of high speed, light craft and naval surface craft, RU HSLC Pt.1 Ch.1 Sec.2 [1.3]. 1.2.3 Essential machinery- and vessel piping systems in this section are systems in which a failure will cause loss of main function, or cause deterioration of functional capability to such an extent that the safety of the vessel, personnel or environment is significantly reduced. Guidance note: In general essential systems are: —

cooling water systems

—

lubricating oil systems

—

fuel oil systems

—

feedwater, condensate and steam systems

—

hydraulic oil systems

—

compressed air systems

—

ventilation systems

—

exhaust systems

—

bilge (salvage) systems

—

main seawater systems

—

air, overflow- and sounding systems

—

drainage systems

—

ballast systems. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.4 The following definitions of the vessel's speed is used for the arrangement of machinery and piping system:

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 35

Part 5 Chapter 13 Section 6

SECTION 6 PIPING SYSTEMS

Maximum speed: maximum speed the vessel is designed for. 1.2.5 The redundancy and capacity requirements in this rule section will be based on the vessel's cruising speed. Power units with corresponding systems used for gaining maximum speed will only be defined as essential systems if this is specified by the owner.

1.3 Plans and particulars 1.3.1 Plans and particulars shall be submitted for machinery and hull piping systems according to the rules for classification of ships, Pt.4 Ch.6 Sec.1 [3]. For naval vessels with overall length L of less than 50 m, the plans and particulars given in the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.6 Sec.1 [3] are acceptable. In addition, the following documentation shall be submitted for naval vessels: — plans showing arrangement of all piping systems within each compartment with location of components — arrangement plan showing structurally fire protected- and watertight divisions, including damage and fire control zones if relevant. In addition to the requirements in the rules for classification of ships, plans shall include details of penetrations in watertight- and structurally fire protected divisions.

1.4 Materials 1.4.1 Materials used in the construction of piping systems shall be manufactured and tested in accordance with the rules for classification of ships, Pt.4 Ch.6. For naval vessels with overall length L of less than 50 m, the plans and particulars given in the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.6 are acceptable. When selecting materials due attention shall be paid to long life endurance. 1.4.2 The requirements for lifetime evaluations given in Sec.7 [1] are applicable for essential machinery and vessel piping systems. 1.4.3 Special light weight materials may be considered used in valves and components (when necessary for reduction of weight), provided in accordance with a recognised standard. Measures shall be taken to reduce the risk of galvanic corrosion. 1.4.4 Plastic piping is in general to comply with the rules for classification of ships, Pt.4 Ch.6 Sec.2. For naval vessels with overall length L of less than 50 m, plastic piping shall comply with the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.6. The following constraints apply for plastic pipes: — plastic pipes are not accepted led through structurally fire protected or watertight boundaries — plastic pipes are not accepted in piping systems for flammable fluids or essential machinery and vessel piping systems — low flame spread, smoke generation and toxicity characteristic shall be proven according to a recognised standard.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 36

Part 5 Chapter 13 Section 6

Cruising speed: normal cruising speed used for extended periods.

2.1 General 2.1.1 Piping systems for naval vessels are in general to comply with the design principles in the rules for classification of ships, Pt.4 Ch.6 Sec.3 with the additional requirements given in Sec.7 [1] and in this section. For naval vessels with overall length L of less than 50 m, piping systems shall in general comply with the design principles in the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.6 Sec.3. 2.1.2 When the following systems are defined as essential, each system shall perform with 100% capacity when one component is out of function: — — — — — —

fuel oil systems lubricating oil system cooling systems hydraulic systems pneumatic systems ventilation systems. Guidance note 1: In this connection a component is defined as an active component, a filter or a pressure reduction unit. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: For multi engine plants with minimum 4 engines with engine driven pumps, a complete spare pump ready for mounting may be accepted. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.2 Arrangements 2.2.1 Essential machinery and vessel piping systems shall be designed and located to minimise the effect of battle damage. 2.2.2 Where machinery and equipment essential for the operation of the vessel is separated by watertight or fire divisions, piping systems serving such machinery and equipment shall be separated accordingly. Cross connections may be arranged if means for isolation are provided on both sides of the division. Guidance note: This implies that sea inlets and discharges as well as service and expansion tanks should be located in the same damage zone as the machinery it serves. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.2.3 Precaution shall be taken as to prevent progressive flooding through damaged pipelines between flooded and intact compartments. For this purpose, where any part of a pipe system has an open end into an assumed intact compartment, an isolating valve situated outside the damaged area and operable from an accessible position when the vessel is in damaged condition shall be fitted. Guidance note: For bilge piping, remotely operated valves may be replaced by non-return valves of the shut-down type. Isolation of air pipes may not be acceptable. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 37

Part 5 Chapter 13 Section 6

2 Design principles

2.2.5 Pipes shall in general not be led through chain lockers, sea- and fresh water tanks, fuel oil tanks, spaces or trunks containing electrical and electronic equipment or storage rooms for explosives. 2.2.6 Piping within storage rooms for explosives or light flammable liquids shall have all welded connections.

2.3 Operation of valves 2.3.1 Requirements for operation of valves are given in the rules for classification of ships, Pt.4 Ch.6 Sec.3. In addition, all remotely operated valves in dry compartments shall have means for local manual operation. Such means shall be readily available and simple to execute.

3 Pipes, pumps, valves, flexible hoses and detachable pipe connections 3.1 General 3.1.1 Pipes, pumps, valves, flexible hoses and detachable pipe connections shall comply with the requirements in the rules for classification of ships, Pt.4 Ch.6 Sec.6 with the additional requirements as specified in this section. 3.1.2 Piping systems for naval surface vessels shall in general be joined by butt welding. The number of detachable pipe connections shall be limited to those, which are strictly necessary for mounting and dismantling. Detachable pipe connections that are partly constructed of non-metallic materials shall comply with the requirements for plastic piping in [1.4].

3.2 Pumps 3.2.1 Shut-down non-return valves shall be provided on the pressure side of pumps. 3.2.2 Centrifugal pumps located above their reservoir shall be of self priming type or connected to a priming system. 3.2.3 Remotely operated pumps shall also be arranged for local operation. 3.2.4 For pumps intended to operate against closed valves (e.g. pressurised systems such as the main seawater system), arrangements shall be provided for prevention of overheating of pumps. For displacement pumps, see the rules for classification of ships, Pt.4 Ch.6 Sec.6 [2.2].

4 Manufacture, workmanship, inspection and testing 4.1 General 4.1.1 The requirements for manufacture, workmanship, inspection and testing shall comply with the requirements in the rules for classification of ships, Pt.4 Ch.6 Sec.7 with the additional requirements as specified in this section.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 38

Part 5 Chapter 13 Section 6

2.2.4 Piping systems shall in general be easily accessible for damage control and maintenance purposes.

4.1.3 After installation onboard, all essential machinery- and vessel piping systems shall be subjected to a hydrostatic test at a pressure of minimum 1.5 times the design pressure, minimum 4 bar.

5 Marking 5.1 General 5.1.1 All pipelines shall be marked according to a recognised standard. 5.1.2 Name plates with adequate information shall be attached to all valves and components. For remote controlled valves inside tanks or cofferdams, name plates shall be fitted at the control station.

6 Machinery piping systems 6.1 General 6.1.1 The requirements for machinery piping systems shall comply with the requirements in the rules for classification of ships, Pt.4 Ch.6 Sec.5 with the additional requirements as specified in this section. 6.1.2 Specific requirements for functioning during electrical power failure are given in Sec.7 [1].

6.2 Seawater cooling systems 6.2.1 The arrangement of seawater cooling inlets shall be in accordance with [2.2]. As far as practicable, the cooling system for machinery for propulsion and power generation shall be connected to at least two seawater inlets. 6.2.2 If water inlets for propulsion engines are shared with main water systems or other consumers, it shall be capable of delivering the maximum required capacity to all systems and consumers simultaneously. 6.2.3 Main propulsion engines shall have a separate seawater cooling system. Guidance note: The main seawater system may be used for cooling purposes for other systems. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

6.3 Fresh water cooling systems 6.3.1 Fresh water cooled components in essential machinery systems shall have separate fresh water cooling systems. 6.3.2 Where fresh water cooled components in essential machinery systems are separated by watertight or fire divisions, freshwater cooling systems shall as far as practicable be arranged, with full separation between systems.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 39

Part 5 Chapter 13 Section 6

4.1.2 Welded joints in class III piping systems shall be made by approved welding shops. Qualified welders using approved welding procedures shall carry out the welding.

6.4.1 Arrangement of lubricating oil service tanks shall be in compliance with [3.2]. 6.4.2 It shall be possible to clean lubricating oil filters without interrupting the oil supply. Bypass of filter units is not an acceptable mean of ensuring lubricating oil supply during cleaning. 6.4.3 Drip trays shall be fitted and arranged equivalent to that required for fuel oil tanks and systems.

6.5 Fuel oil systems 6.5.1 Arrangement of fuel oil daily service tanks shall be in compliance with [3.2]. 6.5.2 Fuel oil service tank capacity shall in general comply with the rules for classification of ships, Pt.4 Ch.6 Sec.5, but the calculations should be based on cruising speed as defined in [1.2.4]. Alternative arrangements may be accepted upon special consideration. For naval vessels with overall length L of less than 50 m, the daily service tanks shall have 100% redundancy, i.e. each main and auxiliary engine shall have fuel supply from at least two daily service tanks. 6.5.3 The fuel oil supply lines to propulsion machinery shall be separate from the supply lines to the machinery for power generation. 6.5.4 Remote shut-off valves in supply lines for propulsion machinery shall be separated from those serving machinery for power generation. The control for the remote shut off valves in the different engine rooms shall be located in separate lockers to avoid erroneous operation. 6.5.5 The fuel oil system shall include arrangements for removing water and harmful contaminants. 6.5.6 The fuel oil transfer system shall be arranged such that fuel can be transferred from any tank to any other tank, or transferred to another vessel. Transfer pumps shall be arranged with built in redundancy.

6.6 Air inlets for main and auxiliary engines 6.6.1 General requirements for engine air inlets are given in Sec.7 and Sec.10. For vessels with class notation qualifier NBC these requirements shall be complied with.

6.7 Exhaust systems 6.7.1 All exhaust outlets shall be provided with silencers or equivalent. 6.7.2 Exhaust uptakes for machinery shall not be combined unless precautions are taken to prevent the return of exhaust gases to a stopped engine. Exhaust systems shall be installed to prevent noise and vibration. 6.7.3 The pressure drop in the system shall not exceed the values recommended by the engine manufacturer. 6.7.4 If exhaust outlets are located in the vicinity of the waterline, arrangements for prevention of water ingress shall be provided.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 40

Part 5 Chapter 13 Section 6

6.4 Lubricating oil systems

6.8.1 Hydraulic pumps shall be equipped with high temperature alarm, giving alarm in manned control station. 6.8.2 In systems where rupture of hoses may be critical, flexible hoses shall be arranged with automatic hose rupture shut off valve to stop the outflow of liquid. 6.8.3 Hydraulic systems serving essential equipment shall be arranged in accordance with [3.2]. In systems for remote control of valves, exemptions may be given provided relevant valves are arranged with manual remote control. 6.8.4 Drip trays shall be fitted and arranged equivalent to that required for fuel oil tanks and systems.

6.9 Machinery space ventilation 6.9.1 The capacity and arrangement of machinery space ventilation shall cover demands for operating machinery and boilers at full power in all weather conditions, as well as prevent excessive temperatures due to heat emission from machinery and electrical equipment. Environmental conditions, including ambient temperatures, are specified in the Rules for Classification of Ships, Pt.4 Ch.6. Guidance note: For vessels intended to operate under cold climatic conditions heating appliances of sufficient capacity should be provided in the machinery space(s). For vessels with class notation qualifier NBC, see corresponding requirements. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

6.9.2 One single failure in the machinery space ventilation system shall not result in more than 50% reduction in the ventilation capacity.

7 Vessel piping system 7.1 General 7.1.1 Vessel piping systems shall comply with the requirements in the rules for classification of ships, Pt.4 Ch.6 Sec.4 with the additional requirements as specified in this section.

7.2 Air, sounding and overflow pipes 7.2.1 Arrangement of air, overflow and sounding pipes shall take into account the requirements in [3.2]. Guidance note: For vessels with class notation qualifier NBC, see corresponding requirements. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.2.2 Sounding pipes shall be provided with striking plates. 7.2.3 Fuel oil tanks that can be pumped up shall be provided with overflow pipes.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 41

Part 5 Chapter 13 Section 6

6.8 Hydraulic systems

7.3 Main seawater system 7.3.1 The main seawater system shall in general supply the following: — — — —

fixed and portable fire extinguishing systems as described in Sec.10 driving water for bilge ejectors as described in [7.4] water spray systems for storage rooms for explosives seawater cooling supply to essential machinery and equipment except for cooling for main engines, if relevant — ballast operations, if relevant — pre-wetting systems for vessels with class notation qualifier NBC, protection shall be provided accordingly. 7.3.2 At least one main seawater pump shall be provided in each fire control zone. Guidance note: Note that two additional fire pumps are required in [7.3.8]. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.3.3 The main seawater system shall be either continuously pressurised or arranged with remote start of pumps in order to ensure that water supply is readily available. 7.3.4 For vessels with class notation qualifier NBC, the larger of the required capacity in [7.3.5] and the total capacity required for the pre-wetting shall be applied. 7.3.5 The total capacity of the main seawater pumps shall be as follows: For vessels below 800 tonnes displacement: 3

— 100 m /h plus — the required capacity for fighting a fire in the machinery space, a fire on flight deck and hangar, the required capacity of water spray systems for storage rooms for explosives according to Sec.15, whichever is greater. For vessels from 800 up to 4 000 tonnes displacement: 3

— 150 m /h plus — the required capacity for fighting a fire in the machinery space, a fire on flight deck and hangar, the required capacity of water spray systems for storage rooms for explosives according to Sec.15, whichever is greater. For vessels with 4 000 tonnes displacement and above: 3

— 250 m /h plus — the required capacity for fighting a fire in the machinery space, a fire on flight deck and hangar, the required capacity of water spray systems for storage rooms for explosives according to Sec.15, whichever is greater. For vessels below 400 tonnes displacement the capacity could be specially considered based on calculations of actual sea water need. Guidance note: 3

For vessels above 800 tonnes the capacities include simultaneous operation of: 4 portable bilge ejectors, each demanding 12.5m / 3

h. 8 and 16 hoses respectively, each demanding 12.5 m /h. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 42

Part 5 Chapter 13 Section 6

7.2.4 Due to the possibility of ignition, air pipe outlets from tanks containing flammable liquids or tanks with anodes for cathodic protection shall not be located within the blast zone of weapon systems. Outlets located in the vicinity of such zones shall be provided with flame screens.

7.3.6 Other systems (such as seawater cooling systems) that are connected to the main seawater system and that may operate during fire fighting operations shall be added to the total capacity described in [7.3.5]. Guidance note: Required capacity for bilge and ballast operations need not be included. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.3.7 The required total main seawater pump capacity shall be equally divided between the required number of pumps. 7.3.8 The vessel shall, in addition to the pumps required above, have two independently driven fire pumps. The capacity of each independently driven pump shall as far as practicable be the same as for one of the main seawater pumps. The location of the pumps shall be in the fore and in the aft part of the vessel. The pumps shall be fitted with separate suction lines with length not exceeding 5 m. Other equivalent arrangements may be accepted. For ships of length below 50 m the additional fire pumps may be omitted provided at least two main seawater pumps are provided. 7.3.9 The sectional area of the main seawater pipe and its branch connections shall be sufficient for efficient distribution of the maximum required supply. 7.3.10 Main seawater pumps serving the fire fighting systems and their seawater inlets shall be located within the same fire control zone. 7.3.11 Main seawater pumps separated by watertight- or fire divisions shall not be connected to the separating bulkheads. 7.3.12 The pump connections to the main seawater pipe and the extensions from pumps to main deck (pump risers) shall not penetrate the vertical watertight- or fire divisions bounding the compartment in which the pump is located. 7.3.13 The main seawater system shall be arranged in accordance with [3.2] and shall extend throughout the length of the vessel. The number of branch connections to the main seawater system shall be limited for damage control purposes. 7.3.14 The main seawater system shall be so arranged that all fire hydrants in the vessel, except those in a damaged section can be supplied from a seawater pump not located in the compartment containing the damaged section. 7.3.15 The fire main shall be arranged as a ring main for supply to all areas onboard. Each fire pump shall be so connected to the ring fire main that sufficient supply of water is maintained with single damage to any section of the ring fire main or one fire pump system. 7.3.16 Isolation valves shall be provided in the main seawater system in order to facilitate: — isolation of each of the main seawater pump's connection from the main seawater system — isolation of the main seawater system from damaged sections in adjacent compartments when separated by watertight or fire divisions. 7.3.17 A separation of the different systems defined to be part of the main sea water system into subsystems can be accepted as an alternative to a common main seawater system.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 43

Part 5 Chapter 13 Section 6

The pumps shall deliver the required capacity at a pressure corresponding to a hose pressure of 5 bar with the given number of hoses in operation.

A separate fire system shall incorporate the relevant systems for water-spray. The total capacity for such a 3 fire system shall be as required in [7.3.6], less 50 m /hour. The other requirements to the main seawater system are also relevant for a separate fire system. Combinations of the different sub-systems are acceptable, and then the capacity requirements will be added as relevant.

7.4 Bilge systems 7.4.1 Bilge systems are divided into the following: — main bilge system (salvage) for removal of large amounts of water in an emergency flooding situation — auxiliary bilge system (ullage) for removal of minor amounts of waters (including oily bilge water from machinery spaces) during normal operation. 7.4.2 The main bilge system shall be arranged for efficient drainage of all essential dry compartments through at least one suction in all conditions of trim and heel after sustaining a damage as specified in Sec.5. Guidance note: Essential dry compartments are compartments, which contain components in essential machinery and vessel piping systems. Large dry compartments where flooding will impair the stability of the vessel are also to be regarded as essential. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.4.3 The main bilge system shall be based on ejectors, with driving water supply from the main seawater system. Ejectors shall as far as practicable be distributed throughout the vessel, but one ejector shall be located in each machinery space. Not less than two ejectors shall be provided. Guidance note: Bilge pumps may be accepted, provided capable of operating in submerged condition. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.4.4 The bilge system is normally to consist of a main bilge pipe in each compartment containing an ejector, with branch suctions led to this compartment and to other essential dry compartments. Location of bilge piping shall comply with [3.2]. 7.4.5 Each bilge suction shall as far as practicable be connected to at least two bilge ejectors, with isolation valves at the watertight or fire divisions separating the compartments in which ejectors are located. 7.4.6 Each bilge ejector shall have an overboard discharge outlet within the watertight compartment in which it is located. 7.4.7 In machinery spaces one of the bilge suctions required in [7.4.2] shall be a direct suction. This shall be so arranged that it can be used at the same time as another ejector is drawing from the main bilge line. The direct bilge suction is normally to have a sectional area equivalent to that of the main bilge pipe. 7.4.8 In addition to the branch bilge suctions, an emergency bilge (salvage) suction shall be provided in each machinery space, leading to the largest available power driven pump in each machinery space. The suction pipe shall be provided with a shut-down non-return valve and shall have sectional area equal to that of the line on the pump pressure side. The emergency bilge suction shall be located on the opposite side of the direct bilge suction in [7.4.7].

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 44

Part 5 Chapter 13 Section 6

In such a case the bilge ejectors should be driven from a system with minimum the capacity needed for keeping at least 4 ejectors in operation simultaneously, when the ejector size is in compliance with [7.4.10]. The ejector driving system should also comply with the general requirements to main sea water system.

L B D

= length of vessel between perpendiculars, in m = breadth of vessel, in m = depth of vessel to bulkhead deck, in m.

7.4.10 The total capacity in [7.4.9] shall be divided between the number of bilge ejectors provided. The capacity of each ejector shall be in accordance with the volume of the compartments served. The capacity of any unit shall however not be less than 10% of that given in [7.4.9]. 7.4.11 In addition to the permanent bilge units, portable submersible bilge pumps and portable bilge ejectors shall be provided as follows: — 1 pump and 1 ejector for vessels below 500 tonnes displacement — 2 pumps and 2 ejectors for vessels between 500 and 1 500 tonnes displacement — 4 pumps and 4 ejectors for vessels above 1 500 tonnes displacement. For vessels with displacement above 6 000 tonnes the required number of portable units will be specially considered. 7.4.12 Connections for power supply to portable bilge pumps, driving water for portable ejectors and overboard discharge shall be provided on damage control deck. Such connections shall as far as practicable be provided for every watertight compartment and on both sides of the vessel. 7.4.13 Half of the portable bilge pumps shall have capacity sufficient for emergency drainage of essential compartments, considering loss of one main ejector. The remaining pump(s) is accepted with smaller capacity. Guidance note: 3

3

Pump capacities need not exceed 100 m /h and 36 m /h, respectively. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--3

7.4.14 Bilge ejectors shall have a minimum capacity of 12.5 m /h. 7.4.15 The following valves essential for the operation of the main bilge system shall be remotely operated from above the damage control deck as follows: — valves in driving water supply lines from main seawater system to bilge ejectors — valves in overboard outlets from bilge ejectors — isolation valves where bilge lines penetrate boundaries of the watertight compartments in which ejectors are located — valves serving one bilge suction in the watertight compartment in which the ejector is located. 7.4.16 Dry compartments not covered by the main bilge system shall be arranged for drainage by portable bilge pumps. 7.4.17 An auxiliary bilge system shall be installed for drainage of oily bilge water from all machinery spaces and transfer to bilge water tanks, reception flange on deck or overboard through a bilge water separator according to [7.6].

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 45

Part 5 Chapter 13 Section 6

3

7.4.9 The total capacity of the main bilge system in the vessel, in m /h, shall be as follows:

7.5.1 Essential dry compartments located above the waterline shall normally be provided with drain pipes of sufficient capacity for removal of fire water. 7.5.2 For vessels with class notation qualifier NBC, drain pipes led to within the vessel or overboard shall be arranged to preserve gas tight division.

7.6 Oil pollution prevention 7.6.1 Requirements for oil pollution prevention according to MARPOL 73/78, Annex I shall be fulfilled as given in the Rules for Classification of Ships, Pt.4 Ch.6 Sec.4.

7.7 Ballast systems 7.7.1 The ballast system may consist of independent pumps or be connected to the main seawater system. Drainage may be provided through the main bilge system. Ballasting by using gravity may be acceptable.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 46

Part 5 Chapter 13 Section 6

7.5 Drainage

1 General requirements 1.1 Application 1.1.1 Vessels with class notation Naval or Naval support(System) shall comply with the requirements for machinery, propulsion and positioning applicable for main class with the modifications specified in this section.

1.2 Documentation 1.2.1 The following documentation is yard’s responsibility and shall be submitted in addition to documentation as listed in the relevant sections in Pt.4: — shaft alignment calculation — shaft strength calculation for load cases exceeding scope in Pt.4 Ch.4 — steering gear strength calculations for maximum expected loads, according to yards specification (and owners loading profile) — strength calculation for steering gear locking arrangement. The following documentation shall be submitted upon request: — vessel hull deflection calculations for extraordinary flexible hull designs — machinery shafting system analysis, documenting tolerance for hull deflections — documentation from the machinery vendor to document that the maximum deflections on his components as given by the hull deflection analysis is acceptable — evaluation with conclusion on the impact of special naval operating requirements to the machinery — documentation that the engine(s) can tolerate rapid load increase. 1.2.2 Type approvals may be the basis for certification. Additional documentation, such as test report or analysis, may be requested to verify that requirements in this section are complied with.

2 Operational conditions 2.1 Operational conditions 2.1.1 Machinery with foundation and fastenings and machinery systems, including auxiliary systems, shall be designed for the following environmental conditions, both statically and dynamically: permanent trim:

± 5°

permanent list:

± 15°

pitching:

± 10°

rolling:

± 30°, typically with period 10 s for a monohull.

Other values than given above may be used if it can be documented that they are applicable. Environmental conditions less than specified in Pt.4 Ch.1 (rules for classification of ships) will not be accepted. Extreme values are not regarded as acting simultaneously. For simultaneously occurring values, see the rules for classification of HS, LC and NSC, HSLC Pt.4 Ch.1 Sec.1 [1.2] and the rules for classification of ships, Pt.4 Ch.1.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 47

Part 5 Chapter 13 Section 7

SECTION 7 MACHINERY, PROPULSION AND POSITIONING

— — — —

operation during extreme sea and weather conditions rapid acceleration and deceleration of propulsion machinery long time service on part loads long periods in harbour, with machinery out of use.

Details concerning operational requirements shall be decided by the owner. The Society reserves the right to request documentation for compliance with the project specific requirements.

3 Arrangement and system design 3.1 Basic principles 3.1.1 Main functions of the vessel shall be available at all times. This implies that: — single failure in any main unit shall not lead to complete loss of main functions — single failure of active component in auxiliary systems shall not result in reduced capacity of main functions. 3.1.2 Naval vessels shall have extra robustness to provide damage limitation. This is ensured by: — duplication and separation of equipment — use of separate compartments.

3.2 Machinery space arrangements 3.2.1 In order to accommodate a wide range of naval craft with different requirements for survivability, the following machinery space arrangements are defined: — basic machinery space configuration (B): — main propulsion units placed in one compartment — there is no requirement for propulsion power after flooding or fire in the machinery space. — This arrangement requires acceptance by the owner. — standard machinery space configuration (S): — Main propulsion units are placed in separate compartments divided by a watertight and fire insulated bulkhead. — Reduced propulsion power will be available after flooding or fire in any of the compartments. — enhanced machinery space configuration (E): — Main propulsion units placed in separate compartments with a compartment in between where the bulkheads are watertight and fire insulated. — Reduced propulsion power will be available after fire in any one of the compartments or flooding from a certain damage length as defined in Sec.5. — Machinery space configuration standard (S) is considered as default unless otherwise agreed. 3.2.2 For standard (S) and enhanced (E) machinery space configurations, the following applies: — the propulsion lines shall be separated from each other with respect to fire

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 48

Part 5 Chapter 13 Section 7

2.1.2 Machinery with foundation and fastenings and machinery systems with control systems shall be designed for long time operation at full load. Operation requirements pertaining to naval surface vessels may also include:

3.3 Redundancy 3.3.1 Machinery systems shall be arranged with built in redundancy according to Table 1. 3.3.2 Lifting fans with shafting and prime movers shall be considered as part of the propulsion machinery. Table 1 Main unit redundancy Main function propulsion:

Main units

Redundancy

— engine / turbine/electric motor — reduction gear — shaft

The vessel shall be provided with sufficient redundancy of main units to ensure propulsion power in the event of single failure in any main unit with sufficient speed to ensure the ability to steer.

— propeller / water jet unit / azimuth thruster — control and monitoring system steering:

A single main steering gear shall be supplemented by an auxiliary steering gear. Auxiliary steering gear is defined as equipment other than any part of the main steering — rudder actuator gear necessary to steer the vessel in the event of failure — control and monitoring system in the main steering gear. See Pt.4 Ch.10. — main steering gear

— power actuating system

electrical power supply:

The vessel shall be provided with sufficient redundancy of main units to ensure propulsion power and steering ability in the event of single failure in any main unit.

— engine — shaft — gear, if any — generator — main switchboard — control and monitoring system

3.4 Arrangement of air intake 3.4.1 In the case where combustion air is fed directly to the engine via external ducts; water drainage systems and filters to remove salt shall be included in the air intake. The air quality shall be in accordance with engine manufacturer's specification.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 49

Part 5 Chapter 13 Section 7

— auxiliary systems for each propulsion line shall be arranged to comply with the requirement to survivability of the applicable machinery space arrangement defined in [3.2.1].

4.1 Propeller 4.1.1 The propulsion line shall be designed such that the blade failure load (see below) shall not cause damage in other parts of the propulsion line (i.e. blade connection to hub, propeller hub, pitch mechanism, shaft connection and aft end of propeller shaft). Blade failure load is the load causing plastic bending of the propeller blade in a section just outside the root fillet. Guidance note 1: By damage in this context should be understood as when the stresses in the highest loaded part of the considered cross section reaches yield stress. The local effect of stress raisers may be ignored. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: Formula for blade failure load may be found in the Rules for Classification of Ships, Ch.1 Sec. 4 [10.4] as formula for FICE. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.2 The propeller design shall accommodate repetitive lifting of propeller out of water at full speed and subsequent submerging. If not otherwise documented, it shall be taken as 1.0. See Pt.4 Ch.5 Sec.1 and DNVGL-CG-0039.

4.2 Shafting and vibration 4.2.1 For vessels equipped with more than one shaft, the shafts shall be equipped with a shaft brake. 4.2.2 Due to long-time part load operation and frequent speed variations, barred speed ranges are not accepted for normal operation of propulsion machinery. Barred speed ranges may be accepted for operation of engine with one cylinder misfiring. Special attention shall be made to avoid resonance in the shafting system in the low-speed region.

4.3 Steering gear 4.3.1 Each rudder shall be equipped with an effective locking mechanism to stabilize the rudder in case of damage or change of steering gear. The locking mechanism shall be designed with capacity to withstand forces equivalent to 25% of rule rudder torque (QR, as defined in the rules for classification of ships, Pt.3 Ch.14 Sec.1 [2] and the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.3 Ch.5 Sec.1 [5.4.2]).

4.4 Thrusters 4.4.1 Auxiliary azimuth thruster that shall serve as propulsion thruster in emergency conditions shall comply with the Rules for propulsion thrusters in Pt.4 Ch.5 Sec.3 [6.2.2] and Pt.4 Ch.5 Sec.3 [6.2.3].

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 50

Part 5 Chapter 13 Section 7

4 Component specific requirements

1 General requirements 1.1 Application 1.1.1 Vessels with class notation Naval or Naval support(System) shall comply with the requirements for electric power generation and transfer applicable for main class with the modifications specified in this section. 1.1.2 This section shall govern whenever there is a conflict between the requirements of this section and Pt.4 Ch.8.

1.2 Definitions Casualty power system 1.2.1 A distribution network of portable and permanently installed cables and connection terminals to provide temporary power supply to damaged parts of the permanent electrical installation. Damage control system(s) 1.2.2 Vessel systems with primary objective to: — take preliminary measures to prevent damage to the vessel — minimize and localize damage — accomplish emergency repairs, restore equipment to operation, and care for injured personnel. The services to be included in the damage control system(s) shall be as specified by the owner. Guidance note: Examples of damage control system functions: —

preserve or re-establish watertight integrity, stability, manoeuvrability, and offensive power

—

control list and trim

—

repair material and equipment

—

limit the spread of, and provide protection from fire

—

limit the spread of, remove the contamination by, and provide adequate protection against chemical and biological agents or noxious gases and nuclear radiation

—

care for wounded personnel. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Darkened ship 1.2.3 A situation where all normal lighting, including navigating lights, are switched off and hatches closed. Low intensity illumination (see [7.8]) is accepted switched on. Essential equipment 1.2.4 In addition to the services defined in Pt.4 Ch.8 Sec.13 [1.3.1], the following services shall also be considered essential for the Naval notation: — systems necessary to maintain satisfactory operation of the weapon systems and the damage control services.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 51

Part 5 Chapter 13 Section 8

SECTION 8 ELECTRIC POWER GENERATION AND TRANSFER

1.3.1 The following information shall be submitted for approval: — power consumption balance for the “alongside” operational mode. Guidance note: The balance should give information necessary to have correct dimensioning criteria for the shore connection circuits. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2 Design principles 2.1 Environmental conditions 2.1.1 All electrical components shall be able to withstand electric static distortion as specified by the owner.

2.2 Earthing 2.2.1 Aluminium superstructures, which are provided with insulating material between aluminium and steel in order to prevent galvanic corrosion, shall be earthed to the hull. For this purpose, corrosion-resistant metal wires or bands shall be used. The distance between such connections shall be less than 10 m. Aluminium superstructures shall be earthed to at least 4 points. The total resistance of all connections for 2 one superstructure shall be less than that equal to 50 mm copper, and the resistance of each connection 2 shall be less than that equal to 16 mm copper. Measures shall be taken to prevent corrosion at the point of connection.

2.3 Marking 2.3.1 Switchgear and safety equipment for each circuit shall be marked with: — circuit number, name of the equipment supplied, location of equipment, fuse current, or adjustment of over-current protection 2.3.2 Wires and cables in control boards and connecting systems, except for very short lengths of internal wires, shall be marked near their ends. The marking shall be in accordance with the designations given in the corresponding wiring diagram.

2.4 Indicator lights 2.4.1 The colour of the indicator lights shall normally be chosen in accordance with Table 1 to Table 2. The choice and number of colours and use of flashing or continuous light depends on the type of alarm, or signal system. Flashing lights shall normally be used in instances where messages require immediate action. When indicator lights are used to indicate the position of remote operated valves and cowl ventilators, the colours of the lights shall be in accordance with Table 3.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 52

Part 5 Chapter 13 Section 8

1.3 Documentation

Colour

Significance

Examples of use

red

crisis alarm

Stop of important machinery, e.g. steering gear, lubricating oil pump for propulsion machinery or other motors. Pressure failure in lubricating oil system for propulsion machinery, hydraulic system. Near critical level for temperature and pressure (water, oil). Breakdown of important connections.

yellow or amber

warning of abnormal conditions

Temperature and pressure conditions that deviate from normal level. Temperature rise of cooling water, but not to a critical value.

green

normal condition

Engine operation, liquid circulation. Pressure, temperature, current.

blue

instruction and information

Engine ready to start. No generators ready for connection. Electric heating circuit for electric machines out of order.

white or clear

additional indications and general information

Earthing failure indicator. Synchronising lamps. Telephone calls. Automatically controlled equipment.

Table 2 Colours of rotating warning lights Colour

Significance

red

Clear ship alarm. Action station alarm. NBC alarm. Damage control alarm.

blue

fire-medium release alarm

yellow

machinery surveillance (E0-alarm)

white or clear

telephone call in noisy room or space

Table 3 Colour of indicator lights used to indicate the position of remote operated valves, cowl ventilators Colour

Significance

red

closed

green

open

3 System design 3.1 Supply systems 3.1.1 The following supply systems are normally to be used: a)

In D.C. installations: — two wire, insulated.

b)

In A.C. installations: — single phase, two wire, insulated neutral point — three phases, three wire, insulated neutral point. Guidance note 1: Other supply systems may be accepted on a case-by-case basis and upon agreement with the owner.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 53

Part 5 Chapter 13 Section 8

Table 1 Colour of indicator lamps

Guidance note 2: The number of system voltages should be kept as low as possible. The design should take into consideration the possible interface to other vessels and shore systems. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.2 D.C. voltage variations 3.2.1 D.C. Generators D.C. generators shall not be used for feeding distribution systems onboard naval surface vessels.

3.3 Main source of electrical power 3.3.1 System requirements a)

The installation shall consist, as a minimum, of two mutually independent electrical power supply systems. Each system shall consist of an electrical source of power and an associated main switchboard. Guidance note: The requirement for independence is also valid for all auxiliary systems (e.g. fuel oil, lubricating oil and cooling water) and alarm, control and safety systems. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

b)

With any one of the two main electrical power supply systems out of operation, the remaining shall have capacity to supply power to all services necessary to keep the vessel in normal operational and habitable condition. In addition there shall be sufficient capacity to supply the vessel's combat systems.

3.3.2 Arrangement The two power sources and their main switchboards respectively, shall be located in separate watertight compartments with at least one compartment in between. In the event of flooding of one generator space plus the intermediate compartment, the remaining power source and its associated main switchboard shall still be fully operable. Guidance note: The damage length with regards to flooding is defined in Sec.5 [3.2]. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.3.3 The fire integrity of the boundaries of the spaces containing the main power sources and their associated main switchboards shall be in accordance with SOLAS Ch. II-2 Reg. 9.2.3 Table 9.5 and 9.6, but shall not be less than A-60 when adjacent to a machinery space of category A. Guidance note: One generator and corresponding switchboard shall normally be in the same watertight compartment and fire control zone. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.3.4 For vessels with basic engine room configuration B, as defined in Sec.7, an electrical system with one main source of power and one emergency source of power in accordance with Pt.4 Ch.8 may be accepted.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 54

Part 5 Chapter 13 Section 8

---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Where redundancy in main source of power is waived for small naval vessels, any requirement for redundancy in main transforming equipment and/or the main distribution system is also waived. Guidance note: Choice of a simplified system arrangement as described in [3.3.4]/[3.3.5] above shall be communicated with the owner. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.3.6 Duplicated essential or important equipment shall for each equipment type be divided between different main switchboards or between distribution switchboard supplied by different main switchboards. 3.3.7 Where only one main switchboard is installed in accordance with [3.3.4], the main bus bars shall be divided into at least two parts by use of a circuit breaker. The generating sets and other duplicated essential and important equipment shall be equally divided between the parts. 3.3.8 Essential or important equipment, which are not duplicated, shall have two sources of power supply. The primary supply shall be from the primary main switchboard and the alternative supply from an alternative main switchboard. A transfer switch shall allow switching between the primary and the alternative power supply. Local manual switching shall be available for all relevant equipment. For essential equipment, automatic switching shall be arranged. Guidance note: a)

The requirement for automatic switching applies in general for e.g. steering gear and steering machinery control systems, electric alarm and control systems for main and auxiliary machinery, as well as electric “stand by” oil pumps and weapon systems.

b)

Consideration should be given to the need for remote switching from a manned control position. See the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.1 Sec.3 [2]and HSLC Pt.4 Ch.1 Sec.3 [3] and the rules for classification of ships, Pt.4 Ch.9 Sec.2 [1] and Pt.4 Ch.9 Sec.2 [2].

c)

Manual transfer switches used, shall be located near the equipment, so that operation of this can take place as part of the reconnection procedure, unless otherwise specified. Consideration should be given to the possible connection of two separate power systems.

d)

When only one main switchboard is installed in accordance with [3.3.4], the two sources of power supply may be taken from different halves of the main switchboard. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.4 Emergency source of electrical power 3.4.1 The requirements for emergency source of electrical power which are given in Pt.4 Ch.8, are not made applicable to naval surface vessels. Availability and independence are covered by the requirement for alternative source of power as required by [3.3] and [3.6]. For vessels with basic engine room configuration (B), the requirements in Pt.4 Ch.8 Sec.2 [3] may be applied. Reference is made to [3.3.3] above. 3.4.2 At least one generator in each main power supply system shall comply with the requirements for emergency generator. 3.4.3 Naval vessels with rule length less than 50 m shall comply with the requirements for emergency source of power given in Pt.4 Ch.8 Sec.2 [3], where redundancy in the main source of power is waived according to above reference. The emergency source of power shall be capable of simultaneously supplying the services listed in rules for classification of high speed, light craft and naval surface craft, RU HSLC Pt.5 Ch.1 Sec.5 [1.2.2].

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 55

Part 5 Chapter 13 Section 8

3.3.5 The requirements in [3.3] are not made applicable for small naval vessels (with rule length less than 50 m). For small naval vessels the main electrical power system shall be in accordance with Pt.4 Ch.8 Sec.2 [2].

3.5.1 General A casualty power distribution system shall be arranged to provide temporary power supply to damaged parts of the permanent electrical installation. The casualty power cable network shall consist of portable flexible cables and casualty power connection terminals. The number and length of permanently installed casualty power cables shall be kept to a minimum. 3.5.2 System requirements Casualty power supply connections shall be provided for at least the following services: — — — — — — — — — — — —

fire fighting foam station switchboards communication switchboards fire and bilge pump starters main switchboards and load centres (in the design of the casualty power systems, these switchboards are considered as sources of casualty power) CIWS and other craft self-defence switchboards IC switchboards lighting system transformers (except when located with casualty power equipped switchboards) machinery space propulsion and electric plant auxiliary control centres or switchboards distribution switchboards serving receptacles for portable submersible pumps and other damage control equipment steering gear switchboards damage control switchboards hospital/sick bay.

3.5.3 Arrangement a)

b) c) d)

Fore and aft casualty power runs shall be established port and starboard throughout the damage control deck. Alternatively the casualty power runs may be established throughout a continuous deck below the main deck, having through fore and aft access. Vertical risers shall be provided from the deck containing the horizontal run to switchboard spaces and to spaces with consumers requiring casualty power on other deck levels. The connection between terminals and the portable flexible cables shall be of pluggable/lockable type. Permanently installed cables shall be limited to risers. Where structural arrangements prevent the use of bulkhead terminals, two riser terminals, connected by a short length of permanent cable, may be installed.

Sufficient cable with plug assemblies shall be provided within a compartment to connect casualty power terminals on switchboards, lighting transformers, panels, and controllers to bulkhead terminals within the space.

3.6 Distribution 3.6.1 Sub-distribution systems or boards or panels supporting different naval functions shall be kept separated, each having supply from one or more main switchboards, as required in [3.3.5]. Guidance note: The intention is to separate e.g. weapon systems, navigation systems, NBC systems, non-important naval systems. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 56

Part 5 Chapter 13 Section 8

3.5 Casualty power distribution system

3.6.3 The main lighting shall be arranged as at least two separate secondary systems supplied from different main switchboards. Light sources in each compartment, except for galley and deck lighting, shall be equally distributed between the systems. In case of failure of one of the lighting transformers, the remaining transformer(s) shall have capacity to supply all main lighting via manual connection. Lighting transformers shall be of an air-cooled three-phase type. 3.6.4 Navigation lights Switchboards for navigation lights shall be located in the wheel house, being equipped for regulating the luminous intensity from maximum to zero for all lights simultaneously. Emergency lanterns shall have 24 V D.C. supply connected to a separate switchboard and have a separate cable leading to the fixture. Guidance note: Reference is made to International Regulations for Preventing Collisions at Sea 1972 with later amendments (COLREG). ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.6.5 Signal lights shall have a separate switchboard located in the wheelhouse or an adjacent, easily accessible compartment. The switchboard shall be supplied as described for navigation lights, see the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.11.

3.7 Shore connection 3.7.1 In the main switchboard, the shore connection circuit shall be provided with a circuit breaker with short circuit and over current protection. The breaker shall normally be interlocked with the generator breakers so that the shore connection cannot be effected when one or several generators are connected, and vice versa. A bypass function of this interlock may be arranged to give possibility for short time (maximum 5 s) synchronising of shore and vessel systems as to prevent black-out upon shifting from one source to another. A phase switch or phase sequence protection shall be mounted for vessels with three-phase plant. 3.7.2 In plants with several main switchboards, the shore connection shall be located in the connection area of the primary main switchboard. Power supplies from ashore and from another vessel shall not take place simultaneously. 3.7.3 For vessels constructed of aluminium, shore connections shall be through isolating transformers.

3.8 Choice of cable and wire types 3.8.1 Only cables and wires of temperature class 85°C or higher shall be used. 3.8.2 Cables and wires shall be chosen as to minimise the possibility of smoke evolution and release of halogens during a fire. Guidance note: Relevant standards are * IEC 60754 (1/2) for halogen-free cables * IEC 61034 for low smoke cables. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 57

Part 5 Chapter 13 Section 8

3.6.2 If the vessel is designed for zone distribution, where load centres supply groups of loads and consumers located in general proximity to each other, [3.3.6] and [3.3.8] are still applicable. Loss of a load centre shall not lead to loss of important or essential functions for the vessel.

— navigation systems — combat systems — communication systems. Exceptions may be made for cables located in the same fire zone or compartment as the equipment it supplies, and for redundant cables run in different fire zones or compartments.

3.9 Control gear for motors and other consumers 3.9.1 D.C. motors should normally not be used. If being the only possible solution, it shall be possible to start D.C. motors of up to 0.5 kW upon direct connection of full voltage.

3.10 Battery supplies 3.10.1 Supply to weapon-electronics, navigation and platform management systems from starting batteries shall be avoided. 3.10.2 Charging equipment shall be dimensioned for the maximum load and the maximum load current that occurs while charging the batteries. There shall be automatic control to prevent overloading. Temperature controlled charging shall be used. 3.10.3 For buffer operation, or other situations where the battery is loaded while the battery is being charged, the maximum charge voltage shall not exceed the maximum allowable voltage for any appliance connected. If this is not possible, a voltage adapter, or some other method of voltage control, shall be used.

4 Switchgear and control gear assemblies 4.1 Mechanical construction 4.1.1 The switchboard construction shall be of a design preventing accidental operation of the breakers or switches. Guidance note: An acceptable construction is having the operator handle in line with the switchboard front panel. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4.2 Remote operated switchboard 4.2.1 If remote operated switchboards are used, the possibility for manual operation shall be designed for fulfilling the requirements in Pt.4 Ch.8. Damage to the remote control system or cables supporting this function shall not jeopardise the possibility of manual operation of the switchboard.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 58

Part 5 Chapter 13 Section 8

3.8.3 Cables supplying the following functions shall be of a type fulfilling the requirements to fire resistant cables defined in IEC 60331 Series:

5.1 Motors 5.1.1 Motors shall be designed in accordance with specified radio interference requirements for the vessel. Motors shall not emit disturbing mechanical operating noise in the normal operating area.

6 Miscellaneous equipment 6.1 Switchgear 6.1.1 Mercury switches are not permitted. 6.1.2 Remote operated circuit breakers shall have the possibility for manual operation in case of an emergency.

6.2 Galley equipment 6.2.1 All fixed galley equipment shall be supplied from one or more isolating transformers.

6.3 Batteries 6.3.1 Battery cells shall be designed to prevent electrolyte leakage from occurring on heeling up to 40°.

7 Installation and testing 7.1 Principles 7.1.1 Electric cables and equipment shall be located so that they are not in the way when machinery shall be installed or dismantled.

7.2 Generators 7.2.1 The generator sets, including frames, shall be so rigid that extra stiffening after installation in unnecessary. All pipe and cable connections shall be flexible enough to withstand maximum possible deflections. 7.2.2 The centre line of the generator shaft and the transmission shaft shall coincide. The maximum permissible radial eccentricity in the generator shaft is 5/100 mm. In the case of diesel prime movers the shaft eccentricity shall not exceed 5/100 mm between the crank arm in the course of one rotation. 7.2.3 The generator sets shall be located on vibration damping elements.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 59

Part 5 Chapter 13 Section 8

5 Rotating machinery

7.3.1 Location As far as possible the switchboards should be located in athwart-ships direction.

7.4 Cables 7.4.1 Cable runs through compartments that may be flooded shall be installed as high as possible. 7.4.2 Cables for equipment which require two alternative power supplies (in accordance with [3.3] or [3.6]), and for equipment which is duplicated because of its importance, shall be laid to achieve the maximum degree of transverse and vertical separation. 7.4.3 Cable installations in the radio room shall be limited to radio station requirements. The radio room shall be regarded as screened, and the laying of extraneous cables through such rooms is not permitted. 7.4.4 At the interface between hull and machinery, the cables shall have enough slack to prevent them being damaged by vibration. On resiliently mounted equipment, cables shall have slack between the last fastening point and the entrance to the equipment. The slack of cable and cable fixing point shall allow for relative movement by vibrations of the machinery. 7.4.5 The protection provided by the vessel’s hull shall be exploited to the full. Where practicable, cables shall be laid on the inner side of beams and other parts of the construction. Cables shall not be laid externally on superstructures unless absolutely necessary, and in cases where this must be done, they shall be protected as specified in [7.4.9]. 7.4.6 Cables shall not be installed such that they are permanently submerged unless the whole installation is approved for such applications. 7.4.7 Where plastic pipes are used, consideration shall be given to plastic’s large thermal expansion coefficient and to radio interference. 7.4.8 Cables shall normally not be painted. Guidance note: Painting of cables can be accepted provided that it is documented that the paint does not damage the cables. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.4.9 Airtight compression and threaded glands shall normally be used when laying cables through airtight bulkheads. Other methods may be accepted if requirements to tightness can be achieved through good fitting and use of sealing compounds. 7.4.10 When single compression glands are used, a sealing compound shall be used as filling around the cable on both sides of the penetration. 7.4.11 Cables passing through a deck shall be supported and mechanically protected up to a height of at least 200 mm above the deck. 7.4.12 Cables laid through insulation in the refrigeration and cooling rooms, shall be laid in heat insulated penetrations of wood, plastic or similar heat insulating material. 7.4.13 Cables shall normally not penetrate watertight bulkheads under the damage control deck. Guidance note:

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 60

Part 5 Chapter 13 Section 8

7.3 Switchboards

penetration will withstand the strains the bulkhead is designed for. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.5 Screening and earthing of cables 7.5.1 The cable’s sheath, armouring, braiding or screening shall normally be earthed at both ends of the cable. Guidance note: Normally not applicable for mine warfare vessels. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.5.2 The screening the vessel structure itself may provide, shall be exploited to the maximum. Cable shafts and ducts shall be used if necessary. 7.5.3 For vessels of non-conductive materials, exceptions from the above may be given. Guidance note: Special magnetic signature requirements may require other solutions. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.6 Marking of cables 7.6.1 Each permanent fixed cable shall be marked so that it can be identified in all separate compartments where it is required to be accessible. If the cable can be easily tracked within one compartment, marking at one side is sufficient. Guidance note: In practice this means that cables should be marked at junction points, and on each side of penetrations in the deck or bulkhead. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.6.2 For cable penetrations with several cables, marking of the individual cables may be omitted. Instead an identification signboard shall be mounted adjacent to the penetration. This shall give the cable’s reference designation relevant to its place in the penetration. Identification signboards shall be white with black engraving, and be fixed with screws to the bulkhead. 7.6.3 Marking of individual cables shall be in accordance with the cable identification made in the drawings.

7.7 Batteries 7.7.1 Batteries shall be installed so that protection against vibration is achieved. 7.7.2 Battery boxes exposed to wind and weather shall have a drainage outlet in the base. 7.7.3 Ventilation air to the battery location shall be preheated or drawn from a heated compartment.

7.8 Low intensity illumination 7.8.1 A low intensity lighting system shall be installed in addition to the required normal lighting. The low intensity lighting shall provide illumination during “darkened ship” operation. The low intensity illumination wave-length shall be 600 nm or more.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 61

Part 5 Chapter 13 Section 8

If such cable penetrations are unavoidable, a watertight cable penetration may be accepted. It should be documented that the cable

7.8.3 Low intensity illumination shall be installed or shaded to prevent, at any time, the light showing outside of the vessel. 7.8.4 Low intensity illumination shall not be connected to door switches. This lighting shall be connected to separate circuits from the nearest light switchboard. All switches shall have double poles and be appropriately located. The switches shall be specially marked. 7.8.5 Low intensity illumination fixtures shall be installed along passage ways that lead from the accommodation to the control stations. Where access is through large rooms, such lights shall only be installed as passage lights. 7.8.6 Washrooms and lavatories with doors to access passages shall have low intensity illumination. This lighting shall also be installed in accommodation as well as in washrooms and lavatories outside accommodation. It shall be installed as continuous lighting. 7.8.7 Normally low intensity illumination shall be installed at plotting tables and working stations. The fixtures shall have dimmers.

7.9 Emergency lighting 7.9.1 There shall be installed an emergency lighting system throughout the vessel to provide minimum illumination necessary to carry out at least the following activities: — — — —

restoration of main power repair work on equipment - in technical rooms medical surgery fire fighting.

The emergency lighting shall as a minimum cover: — — — —

all service and accommodation alleyways, stairways, exits and emergency exits personnel lift cars and lift trunks machinery spaces and main generating stations, including their control positions and switchboards stowage positions for firemen’s outfit.

7.9.2 The emergency lighting shall be operable for a minimum of 3 hours. 7.9.3 The source of power for the emergency lighting shall normally consist of accumulator batteries located within the lighting fixtures. The batteries shall be continuously charged. Guidance note: Alternative arrangements providing the same availability of the emergency lighting may be accepted. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.9.4 It shall be possible to switch off the emergency lighting.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 62

Part 5 Chapter 13 Section 8

7.8.2 Fixtures for low intensity illumination shall be mounted so that light does not normally shine directly into the eyes. (E.g. when they are installed right next to berths, at the top of stairs and ladders). If necessary the globes shall have metal shades.

8.1 General 8.1.1 The requirements of [8] apply in addition to those of Pt.4 Ch.8 and other parts of this section, and are applicable to propulsion machinery or systems on vessels where the main propulsion consists of electric motor(s).

8.2 Design principles 8.2.1 Propulsion motors a) b) c)

The motors may be cooled by air or water. In case of water cooling, only double piped freshwater coolers with temperature and leakage alarms will be accepted. There shall be redundancy in the propeller motor cooling system. Load capability at reduced cooling shall be specified. Ball and roller bearings or slide bearings may be used. Motors having bearings with pressurised lubrication shall have their own individual lubrication system, that meets the requirements of banking and heeling, see Sec.7.

8.3 System design 8.3.1 The following supply systems are accepted for the electric propulsion system: — insulated — high impedance earthed. Guidance note: The power system should withstand a single-phase earth fault for 30 minutes and the fault current shall be limited to 2 A. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 63

Part 5 Chapter 13 Section 8

8 Electric propulsion

1 General requirements 1.1 General 1.1.1 The requirements in this section are of a general character in as much as the damage control and monitoring philosophy depends on the vessel’s prescribed operating philosophy. The principles identified apply to specified control and monitoring tasks.

1.2 Application 1.2.1 Vessels with class notation Naval or Naval support(System) shall comply with the requirements for control and monitoring applicable for main class with the modifications specified in this section.

2 Documentation 2.1 Requirements for documentation 2.1.1 The plans and particulars that shall be submitted are given in Pt.4 Ch.9 Sec.1.

3 System design 3.1 General 3.1.1 The systems shall be designed to enable future modification, upgrade and replacements.

3.2 Data communication links 3.2.1 Data communication links interconnecting essential and important systems in separate compartments shall be duplicated. The cables shall be installed well protected and as far apart as practicable. Guidance note: Due to the probability of hull damage, the cables should not be installed adjacent to the shell plating. Bus networks are typically to be installed on each side, one high, one low. HUB’s for star networks are typically to be installed in a centre position towards the bow and the stern of the vessel. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.3 System independence 3.3.1 A failure in one zone shall not have a negative effect of systems in another zone. Guidance note: Applies to different autonomous zones, if any. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 64

Part 5 Chapter 13 Section 9

SECTION 9 CONTROL AND MONITORING

4.1 Enclosure 4.1.1 Minimum requirement for enclosure on bridge shall normally be IP44 unless the risk for water ingress on the bridge is small.

4.2 Temperature 4.2.1 Table 1 is an extension of Table 1 of Pt.4 Ch.9 Sec.5. Table 1 Parameter class for the different locations on board Parameter

temperature

Class

Location

E

open deck, masts for vessels to operate in arctic climate

F

inside cabinets and desks with temperature rise of 5°C or more installed in location E

4.2.2 class E: ambient temperatures − 40°C to + 55°C 4.2.3 class F: ambient temperatures − 40°C to + 70°C

4.3 Electromagnetic interference 4.3.1 See Sec.14.

4.4 Inclination 4.4.1 See Sec.7 [1.1].

4.5 Sensors 4.5.1 For sensors belonging to essential functions, use of switches shall be avoided as far as practicable.

5 Alarm system 5.1 Alarm system in the accommodation 5.1.1 Any alarm condition in the engine room shall initiate an alarm in the watch-keeping engineer officer’s cabin and day rooms. Acknowledgement in the cabin shall be indicated on the bridge when the engine room is unattended. 5.1.2 [5.1.1] may be waived if the engine room shall be permanently manned.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 65

Part 5 Chapter 13 Section 9

4 Component design and installation

Part 5 Chapter 13 Section 9

6 Damage control system 6.1 General 6.1.1 The damage control system is an essential system. Guidance note: Related to the definition and additional requirements found in Pt.4 Ch.9. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7 Monitoring and control 7.1 General 7.1.1 Workstations for monitoring shall be arranged for the following (as applicable): 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12)

damage stability fire detection fire pumps fire doors ventilation watertight doors bilge ballast seawater main high water level in relevant rooms under water level hatches (as relevant) monitoring of NBC parameters as follows: — — — — —

automatic detection of NBC pollution overpressure in citadel NBC ventilation NBC filters pre-wetting.

Guidance note 1: The above may be combined in an NBCD plotting system. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: The number and position of the workstations will depend upon the type of vessel. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.2 Remote control shall be arranged at these workstations for the following (as applicable): — — — — — —

bilge and ballast systems fire extinguishing systems fans and dampers seawater main pre-wetting electrical power supply.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 66

8.1 General 8.1.1 Means shall be available to override automatic safety actions for essential systems. Overrides shall be clearly indicated and identified.

8.2 Steering control system 8.2.1 The control system for steering of vessels shall be designed to handle extreme operating manoeuvres, and extreme load changes.

8.3 Water jet control system 8.3.1 The control system for water jets shall be designed to handle rapid and numerous subsequent deaerations due to loss of water (sudden load shedding).

8.4 Stabiliser control system 8.4.1 The stabiliser control system shall be designed to handle extreme load changes.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 67

Part 5 Chapter 13 Section 9

8 Control systems

1 General 1.1 General 1.1.1 The requirements for fire protection in this section apply to vessels with class notation Naval or Naval support(Fire) made of steel or other equivalent materials. In addition, the requirements given in SOLAS Ch. II-2 for cargo vessels shall be complied, regardless of tonnage, with unless otherwise stated in this section. For naval vessels equipped to carry fuel that is not for own use, the requirements in SOLAS for tankers shall apply. Guidance note: For the Society's interpretations to SOLAS regulations, see Statutory Interpretations, . ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.2 Fire fighting components and systems required to be of an approved type shall be approved by the Society. Documentation verifying approval shall in such cases be submitted.

2 Rule references and definitions 2.1 Fire technical definitions 2.1.1 For technical and space definitions, see Sec.2 and SOLAS Ch. II-2 Reg. 3 and 9.2.3.

3 Documentation 3.1 Documentation requirements 3.1.1 Documentation shall be submitted as required by Table 1. Table 1 Documentation requirements Object

Documentation type

Additional description

vessel arrangement

Z010 – General arrangement plan

Should including Fire Control Zones (FCZ) and Damage Control Zones (DCZ) in profile and plan view. A note should clarify the chosen engine room configuration, ref. Sec.7. To be submitted as the first drawing in each project.

safety general

G040 – Fire control plan

AP

structural fire protection arrangements

G060 – Structural fire protection drawing

AP

G061 – Penetration drawings

AP

S010 – Piping diagram

AP

fire water system

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Info FI

Page 68

Part 5 Chapter 13 Section 10

SECTION 10 FIRE SAFETY

Documentation type

Additional description

Info

S030 – Capacity analysis

AP

Z030 – System arrangement plan

AP

machinery space fixed fire fighting system

G200 – Fixed fire extinguishing system documentation

AP

machinery space fixed local application water spraying fire extinguishing system

G200 – Fixed fire extinguishing system documentation

AP

cargo, vehicle and ro-ro space fixed fire extinguishing system

G200 – Fixed fire extinguishing system documentation

galley exhaust duct fire fighting system

G200 – Fixed fire extinguishing system documentation

AP

dee-fat cooking device fire fighting system

G200 – Fixed fire extinguishing system documentation

AP

paint locker fire fighting system

G200 – Fixed fire extinguishing system documentation

AP

escape routes

G120 – Escape route drawing

AP

fire detection and alarm system

I200 – Documentation for control and monitoring systems.

AP

Z030 – System arrangement plan

AP

S012 – Ducting diagram

AP

S061 – Duct routing sketch

AP

Z030 – Local arrangement plan

AP

Z090 – Equipment list

AP

ventilation systems

low location lights

helicopter deck foam fire extinguishing system

G200 – Fixed fire extinguishing system documentation

if relevant

if relevant

AP

AP

3.1.2 For general requirements to documentation, see Pt.1 Ch.3 Sec.2. 3.1.3 For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 69

Part 5 Chapter 13 Section 10

Object

4.1 Structural integrity SOLAS Ch. II-2 Reg. 11 shall be complied with. Guidance note: Where an asterisk appears in SOLAS Reg. II-2, table 9.5 and 9.6, doors and hatches may be accepted made of other material than steel if the surface is documented to have low flame spread characteristics. This will typically apply to doors to hangars and escape hatches on weather deck. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5 Fire control zones 5.1 Fire control zones 5.1.1 Naval surface vessels shall be subdivided into fire control zones by “A” class divisions according to the requirements applicable to passenger vessels, ref. SOLAS Reg. II-2/9.2.2. The divisions shall have minimum A-0 class integrity; additional integrity requirements will apply when required by SOLAS Ch. II-2 table 9.5. and 9.6. 5.1.2 Minimum 2 fire control zones shall be provided, irrespective of the length of the vessel. 5.1.3 For ship designed for special purposes, such as closed ro-ro and vehicle, helicopter storage and amphibious-boat spaces, where the provision of the main vertical zone is not practically possible, horizontal main fire zones may be accepted if arranged in compliance with regulations for special category spaces. SOLAS Reg. II-2/20.2.2.1 refers.

6 Fire integrity of bulkheads and decks 6.1 Fire integrity of bulkheads and decks 6.1.1 SOLAS Ch. II-2 Reg. 9.2.3 shall be complied with. 6.1.2 The following spaces shall be regarded as category (1) spaces with regard to fire integrity: Wheelhouse, chartroom. Spaces containing the vessel's radio equipment. Damage control stations, damage control central (when located outside the machinery space), weapon system rooms, rooms containing radar equipment, fire-extinguishing rooms, fire extinguishing equipment rooms. Sonar equipment rooms, sonar instrument rooms, electronic countermeasure rooms, degaussing rooms, gyro rooms, IFF rooms. Control room for propulsion machinery when located outside the machinery space. Spaces containing centralised fire alarm equipment. Operation rooms (combat information centre) and combat system room. 6.1.3 For engine room bulkheads separating main propulsion units, the following apply: — For vessels with standard engine room configuration, the division separating the main propulsion units shall be at least A-60. — For vessels with enhanced engine room configuration, the compartment separating the propulsion units shall be at least 600 mm wide, consisting of A-class boundaries, and be insulated according to SOLAS Ch. II-2 Reg. 9.2.3 Table 9.5 and 9.6.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 70

Part 5 Chapter 13 Section 10

4 Structure

Standard and enhanced engine room configurations are used to describe propulsion redundancy, and are defined in Sec.7. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

6.1.4 Storage rooms for explosives as defined by Sec.15 shall not be arranged below or adjacent to vessels main control centre (wheelhouse and communication central). Sec.15 [5.2] is considered compulsory for all vessels that shall comply with Naval support(Fire).

7 Means of escape 7.1 Arrangement 7.1.1 The arrangement for means of escape shall comply with SOLAS Ch. II-2/13 as applicable to cargo ships. Guidance note: Other escape arrangements that ensure an equivalent safety may be accepted. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.2 In spaces where more than 50 persons may be expected, at least two escape ways shall be provided. 7.1.3 In ships intended for more than 50 persons, no dead end corridors shall be permitted. 7.1.4 One of the escape ways required by [7.1.2] may be arranged as vertical escape through hatches in the deck above with minimum 800 × 800 mm clear light opening (ladders included). The ladder may be of retractable type permanently hinged below the hatch. In such cases, photo luminescent signboard positioned close to the floor level shall indicate the position of the retractable ladder above. 7.1.5 Low location lighting shall be arranged according to SOLAS Ch. II-2 Reg. 13.3.2.5 as applicable to passenger ships > 36 passengers. 7.1.6 Doors to cabins and other spaces in accommodation considered to be frequently manned with only one escape shall be fitted with kick out panels in the lower part of the door.

7.2 Emergency escape breathing devices 7.2.1 Number and position of emergency escape breathing devices in machinery spaces shall be according to SOLAS Ch. II-2 Reg. 13.4.3 and MSC/Circ. 1081. 7.2.2 For accommodation spaces, emergency escape breathing devices shall be positioned according to the following: — — — —

two one one one

in wheelhouse in radio communication centre in each damage control station for each bed, positioned inside the respective cabins.

7.2.3 At least two spare emergency escape breathing devices and one training device shall be provided onboard, and stored in the accommodation area. The devices shall be clearly marked, and spare devices shall not be stored together with the training devices to prevent that the training device is confused with operational devices.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 71

Part 5 Chapter 13 Section 10

Guidance note:

8 Ventilation systems 8.1 Requirements for ventilation system 8.1.1 The ventilation system shall comply with SOLAS Ch. II-2/5.2, 8.2, 9.4 and 9.7 as applicable to passenger ships carrying not more than 36 passengers. 8.1.2 The fire control zones shall be ventilated and served by an independent fan and duct system. Regarding NBC requirements for ventilation systems see the rules for classification of high speed, light craft and naval surface craft, RU HSLC Pt.6 Ch.10. 8.1.3 The main inlets of all ventilation shall as far as practicable be located in a safe distance from the exhaust of weapon systems and outlets from stores and tanks with flammable liquids. 8.1.4 For vessels with standard or enhanced engine room configuration (as defined in Sec.7), the ventilation system serving one propulsion line shall not be connected to the system serving the other propulsion line. The inlets for the two propulsion lines shall be arranged as far as practical apart, to limit the possibility of extracting smoke from an external fire into both systems. 8.1.5 Means shall be arranged for evacuation of smoke from machinery spaces of category A. This may be done either by reversing the engine room ventilation fans, or by dedicated fans. The fans used shall be supplied by the emergency source of power, and the system shall be protected from a fire in the engine rooms. Stairway enclosures and corridors constituting the main escape from accommodation spaces shall be arranged with forced mechanical overpressure ventilation towards adjacent spaces.

9 Material requirements 9.1 Restricted use of combustible material 9.1.1 Materials shall comply with the requirements in SOLAS Ch. II-2 Reg. 4.4, 5.3 and 6 as applicable to cargo vessels.

10 Fire detection system 10.1 Areas to be protected 10.1.1 A fire detection system complying with SOLAS Ch. II-2/7 as applicable to passenger ships carrying more than 36 passengers shall be fitted.

10.2 Requirements for systems 10.2.1 No loop shall cover more than one fire control zone. 10.2.2 For vessels with standard or enhanced engine room configuration (as defined in Sec.7), no loop shall cover more than one main propulsion line.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 72

Part 5 Chapter 13 Section 10

7.2.4 The number and location of emergency escape breathing devices, including spare and training devices, shall be indicated in the fire control plan.

10.2.4 All vessels shall, at all times when at sea, or in port (except when out of service), be so manned or equipped as to ensure that any initial fire alarm is immediately received by a responsible member of the crew.

11 Fixed fire-extinguishing system 11.1 Fixed fire-extinguishing systems for machinery spaces 11.1.1 Machinery spaces of category A shall be fitted with a fire extinguishing system complying with SOLAS Ch. II-2 Reg. 10.4.

11.2 Fixed local application fire extinguishing system 11.2.1 All machinery spaces of category A, regardless of the size of the vessel or the machinery space, shall be protected by an approved type fixed local application fire extinguishing system complying with SOLAS Ch. II-2/10.5.6.

11.3 Design considerations 11.3.1 For vessels with standard or enhanced engine room configuration (as defined in Sec.7), the fire extinguishing systems shall be so designed that full fire extinguishing capabilities are maintained in the machinery space not affected by the fire after discharge in the affected space of a fire extinguishing system required by [11.1] or [11.2]. 11.3.2 The systems serving one propulsion line may be interconnected with the systems serving the other propulsion line provided discharge of the second extinguishing charge is possible by separate manual activation only. Guidance note: The propulsion redundancy is based on the assumption that the second propulsion line is fully operative after a fire incident in the first propulsion line. This includes the fire fighting function. When fire fighting agent intended for the second propulsion line is consumed to fight fire in the first propulsion line, the redundancy requirement is not longer fulfilled. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

11.4 Fixed extinguishing in service spaces 11.4.1 Galley exhaust ducts shall comply with the requirements in SOLAS Ch. II-2 Reg. 9.7.5 as applicable for cargo vessels. 11.4.2 Deep-fat cooking equipment shall comply with the requirements in SOLAS Ch. II-2 Reg. 10.6.4. 11.4.3 Paint lockers and flammable liquid lockers shall comply with the requirements in SOLAS Ch. II-2 Reg. 10.6.3. 11.4.4 Paint lockers shall be effectively ventilated by mechanical or natural ventilation independent of other spaces.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 73

Part 5 Chapter 13 Section 10

10.2.3 Control panels shall be located on the bridge, at each damage control station and, if provided onboard, in the engine control room.

12.1 Portable fire extinguishers 12.1.1 Portable fire extinguishers shall comply with the requirements in SOLAS Ch. II-2 Reg. 10.3. With regard to extinguishing equipment in engine room, SOLAS Ch. II-2 Reg. 10.5. shall be fully complied with.

12.2 Portable foam applicators outside machinery spaces 12.2.1 All naval surface vessels should carry as a minimum 1 portable foam applicator in each damage control stations or a number to the satisfaction of the Society.

13 Fire pumps and fire main 13.1 Capacity of fire pumps 13.1.1 Water for fire fighting purposes shall be supplied from the main seawater system as described in Sec.6. 13.1.2 There shall in addition to the pumps described in Sec.6 be provided at least one portable fire pumps located such that it can be easily transported for assistance. The pumps shall be fitted with independent 3 source of power. The capacity of each portable fire pump shall be at least 25 m /h.

13.2 Water distribution system 13.2.1 In addition to the requirements in Sec.6 [7.3] the requirements in [13.2.2] to [13.2.8] shall be fulfilled. 13.2.2 All isolating valves essential for the operation of the fire water distribution system shall be remotely operated from above the damage control deck. 13.2.3 The pressure at any hydrant shall be in the range of 4 to 8 bars. 13.2.4 In accommodation, service spaces and machinery spaces the number and position of hydrants shall be such that at least two jets of water not emanating from the same hydrant can reach any part of the vessel when all watertight doors and all doors in fire control zones are closed. 13.2.5 The fire hoses shall be of an approved type and the maximum length shall not exceed 18 m. 13.2.6 The number of hoses shall be at least one fire hose for each of the hydrants required in [13.2.5]. 13.2.7 One water fog applicator shall be provided outside each Ro-Ro space, helicopter hangar and spaces for storage of water crafts. 13.2.8 Emergency bulkhead connections for fire hoses shall be fitted in watertight divisions to allow a run of fire hoses through watertight and gastight divisions. The arrangement shall ensure that the watertight and gastight integrity is maintained. However, where the main seawater system is so arranged that one damaged section of the fire main will not impair the supply of water within the watertight zone, emergency bulkhead connections are normally not required.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 74

Part 5 Chapter 13 Section 10

12 Fire-extinguishing equipment

14.1 Number and location 14.1.1 All naval surface vessels shall carry as a minimum four sets of firefighter’s outfits or a number to the satisfaction to the Society. Guidance note: The number will vary with the size of the vessel and fire-fighting philosophy. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

14.1.2 The firefighter’s outfits shall be stored so as to be easily accessible and ready for use 50% of the fire fighter outfits shall be stored in spaces with emergency light and with direct access from open deck. Guidance note: Ready for use implies that an arrangement for hanging up the protective clothing in suspended position shall be provided. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

14.2 Personal equipment and breathing apparatus 14.2.1 The extent of the outfits shall comply with SOLAS Ch. II-2/10.10. The breathing apparatus shall be of an approved type. 14.2.2 A high-pressure compressor with accessories suitable for filling the cylinders of the breathing apparatuses shall be installed in each fire control zone in the safest possible location. The capacity of each compressor shall be at least 75 litres per minute. The air intake for the compressor shall be equipped with a filter. Guidance note: Other arrangement that ensures at least one filling station in each fire control zone may be accepted as equivalent. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

15 Other spaces 15.1 Storage rooms for explosives 15.1.1 Apart for the requirements in [6.1.4], storage rooms for explosives need not comply with the requirements in Sec.15 unless notation Naval support(SAM) or Naval is chosen.

15.2 Spaces containing diving systems 15.2.1 Fire safety requirements for diving systems will only apply if the additional class notation DSV is part of the classification scope.

15.3 Storage spaces for vehicles 15.3.1 Ro-Ro spaces used for storage of vehicles, including helicopters and amphibious-boats with fuel in their tank, shall comply with SOLAS Reg. II-2/20 for vehicle and ro-ro spaces as applicable to cargo vessels.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 75

Part 5 Chapter 13 Section 10

14 Firefighter’s outfit

16 Helicopter facilities 16.1 Helicopter facilities 16.1.1 Helicopter facilities shall comply with SOLAS Ch. II-2 Reg.18. Additional helicopter safety will only apply if the notation HELDK is part of the classification scope. Guidance note: Helicopter facilities may be designed and reviewed towards naval standards upon separate request. Such standards may be APP 2(F)/MPP 2(F) or similar. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

17 Fire control plans 17.1 Requirements 17.1.1 Fire control plans shall be provided as to comply with the requirements in SOLAS Ch. II-2/15.2.4.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 76

Part 5 Chapter 13 Section 10

15.3.2 Other spaces used for storage of fuel, either in free standing tanks or in vehicles with fuel in their tanks, shall be provided with fire detection and a fixed water-based fire extinguishing system as required for machinery spaces of category A. If petrol or other highly flammable liquids are carried, the space shall in addition comply with the requirements in SOLAS Ch. II-2 Reg.20 for ventilation and electrical equipment on ro-ro cargo vessels.

1 General requirements 1.1 General 1.1.1 The requirements for fire protection in this section apply to vessels with class notation Naval or Naval support(Fire) made of FRP and have an overall length of maximum 100 m. 1.1.2 The rules are intended for vessels with a manning level of up to 100 personnel. This figure is a guidance and not a rule restriction. 1.1.3 The requirements shall provide equivalent safety level to that defined by the HSC Code for cargo craft. Acceptance of a large number of crew and relaxed requirements for passive fire protection has been compensated with requirements for a sprinkler system, enhanced requirement for fire alarms and other requirements as specified in these rules. 1.1.4 Some alternative designs are identified in these rules. Other designs that are documented to provide equivalent safety would be accepted. Preference will be given to designs that focus on passive fire protection rather than active fire protection. 1.1.5 Special consideration shall be taken for the protection of weapon systems from fire hazards and the hull shall be protected from heat and blasts in connection with launching of weapons. Separate risk analysis will be accepted as adequate documentation. Battle damage (explosions and associated fires) are not covered by the rules.

1.2 Rule references and definitions 1.2.1 These rules are based upon the rules for classification of high speed, light craft and naval surface craft, HSLC Pt.4 Ch.10 (See HSC Code 7.1 – 7.7 and 7.9 – 7.10). Only additional requirements and exceptions are defined in this section. 1.2.2 “10 minutes fire restricting material” is a material tested according to IMO MSC.40(64) for 10 minutes with 100 kW heat source and meeting the requirements defined by this standard. 1.2.3 A “moderate flame spread material” is a material complying with either of the following standards: — IMO FTP Code part 5 with criteria for floor coverings, or — DIN 4102, Class B1, or — IMO Res. MSC 90(71) with criteria as for furniture. 1.2.4 The “operator” is the owner, navy administration in question or any other, intended to operate the vessel. 1.2.5 For other definitions, see the HSLC rules HSLC Pt.0 Ch.6 and HSLC Pt.4 Ch.10.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 77

Part 5 Chapter 13 Section 11

SECTION 11 FIRE SAFETY REQUIREMENTS FOR FIBRE-REINFORCED PLASTICS (FRP) NAVAL VESSELS

1.3.1 The following plans and particulars shall be submitted for approval: — drawings as specified by HSLC Pt.4 Ch.10 Sec.1 [3] in the rules for classification of HS, LC and NSC, with modifications identified in this section — sprinkler system — ventilation zones, including operation procedures.

2 Structural fire protection, materials and arrangements 2.1 Fire control zones 2.1.1 Vessels with length above 40 m shall be subdivided into fire control zones by 60 minutes fire resisting divisions. Special considerations will be made for vessels with length of up to 60 m, as rooms with minor fire hazards, such as voids, tank compartments and steering gear rooms need not to be included in the calculations for the 40 m zone. Cabins and public areas shall not be located outside the defined fire control zones. 2.1.2 As far as practicable, the bulkheads forming the boundaries of the fire control zones above the bulkhead deck shall be in line with watertight subdivision bulkheads situated immediately below the bulkhead deck. The length and width of fire control zones may be extended to a maximum of 40 m in order to bring the ends of fire control zones to coincide with watertight subdivision bulkheads. The length or width of a fire control zone is the maximum horizontal distance between the furthermost points of the bulkheads bounding it. Such bulkheads shall extend from deck to deck and to the shell or other boundaries.

2.2 Structural fire protection 2.2.1 The requirements for cargo craft in HSLC Pt.4 Ch.10 of the Rules for HS, LC and NSC apply as amended and modified in [2.2.3]. 2.2.2 In addition to the fire resisting divisions specified by the rules, other load carrying structures shall be provided with fire insulation, unless it can be documented, for all parts of the vessel, that a fire in two adjacent compartments will not threaten the structural integrity of the vessel. 2.2.3 For the purpose of these rules, cabins and corridors shall be considered as areas of minor fire hazard. Divisions enclosing these spaces shall be smoketight.

2.3 Material requirements 2.3.1 The requirements in HSLC Pt.4 Ch.10 of the rules for classification of HS, LC and NSC apply as amended and modified in [2.3.2] to [2.3.5]. 2.3.2 The floor and floor covering need not to be of fire restricting material. However, exposed floor surfaces shall comply with HSLC Pt.4 Ch.10 in the rules for classification of HS, LC and NSC (see IMO FTP code part 2 and 5). 2.3.3 “10 minutes fire restricting material” can be applied in auxiliary spaces having little or no fire risk as defined by HSLC Pt.0 Ch.6 in the rules for classification of HS, LC and NSC (pump rooms, switchboard spaces and other technical rooms).

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 78

Part 5 Chapter 13 Section 11

1.3 Requirements for documentation

2.3.5 Surfaces of void spaces and tank compartments need not to be of fire restricting materials. However, such surfaces shall document moderate flame spread properties according to the definition in this section. No fire safety requirements apply to internal surfaces of tanks.

2.4 Arrangements 2.4.1 All doors and hatches in the fire control zone shall be self-closing or automatically closing upon fire detection from any one detector, although they must allow for the exit of people inside the area or compartment. Doors to bathrooms inside cabins need not comply with this requirement.

2.5 Means of escape 2.5.1 The requirements of HSLC Pt.3 Ch.7 in the Rules for Classification of HS, LC and NSC apply as amended and modified in [2.5.2] to [2.5.4]. 2.5.2 Dead end corridors serving only service spaces and machinery spaces in areas well separated from cabins and public spaces can be accepted on a case by case basis. Well separated shall in this context be another deck or another zone or through two doors. 2

2.5.3 All public spaces and cabins exceeding 15 m shall be provided with at least two independent escape routes. The primary escape way shall be provided by corridors, stairways and other spaces independent of 2 2 the space considered. For spaces between 15 m and 30 m the secondary means of escape can be provided 2 by a kick-out panel. For spaces above 30 m the secondary means of escape can be provided by a permanent ladder and hatch arrangement. 2.5.4 Kick-out panels shall be installed in all cabin doors (except doors between cabin and sanitary unit). The kick-out panel shall be operable from both sides in order to provide emergency escape and emergency access to cabins. A door with a kick-out panel shall be regarded as only one means of escape.

3 Ventilation 3.1 Ventilation zones and active smoke control 3.1.1 The requirements of HSLC Pt.4 Ch.10 in the Rules for Classification of HS, LC and NSC apply as amended and modified in [3.1.2] to [3.1.7]. 3.1.2 The ventilation systems in public spaces, cabins and corridors areas shall be divided into zones. 2 Each zone shall not exceed 150 m and shall be enclosed by either fire resisting divisions or smoke tight boundaries. 3.1.3 The ventilation zones shall be independent of each other both with respect to ventilation duct layout and control of fans and dampers. Ducts can be routed through other smoke zones provided that smoke divisions and fire resisting divisions are not impaired. 3.1.4 When in line with the approved smoke control philosophy, balancing duct can be installed in divisions between cabins and corridors without the provision of smoke dampers. Elevation of balancing ducts, air

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 79

Part 5 Chapter 13 Section 11

2.3.4 “10 minutes fire restricting material” can also be applied for cabins and public spaces with a total area 2 of not more than 50 m when a 30 minutes structural fire protection is provided between corridors and the 2 above-mentioned spaces. The boundaries of the 50 m zone shall be protected by standard fire restricting materials.

3.1.5 Each zone shall be designed to operate in the early stage of a fire. All essential components (ventilation fans, any dampers and control system for these) shall be designed to resist the smoke, moist and heat expected in the first 10 minutes of a fire. Guidance note: Materials capable of operating at 200°C can be used for supply ducts, steel or equivalent should be provided for exhaust ducts. Fans and electrical motors with a rating of IP56 or above and cables design according to IEC 332 are considered to meet this requirement, even when located inside the zone or exhaust ducts serving such zones. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.6 The smoke control philosophy shall be defined by the operator of the vessel. 3.1.7 Emergency operation procedures for ventilation system shall be available onboard. The procedures shall define which areas where ventilation shall be shut down in case of fire (stores) and areas where ventilation shall operate in case of fire (cabin, corridors and similar spaces) as per operator philosophy. Drawings and descriptions of smoke zones, fan and damper location and control shall be enclosed. Procedures in case of fire when the vessel is in NBC mode shall be defined.

4 Fire detection system 4.1 Arrangement 4.1.1 The requirements of HSLC Pt.4 Ch.10 in the rules for classification of HS, LC and NSC apply as amended and modified in [4.1.2] to [4.1.7]. 4.1.2 The detection system shall be of an addressable type being capable of identifying each detector. 4.1.3 Machinery spaces of major fire hazard shall be provided with a suitable combination of smoke and heat detectors. In addition, flame detectors shall cover all engines, heated fuel oil separators, oil-fired boilers and similar equipment. One flame detector may as a maximum cover a pair of engines. 4.1.4 Auxiliary machinery spaces of minor fire hazard, cargo spaces, fuel tank compartments and similar spaces shall also be fitted with smoke detectors meeting requirements of HSLC Pt.4 Ch.10 in the rules for classification of HS, LC and NSC. 4.1.5 Areas of no fire risk and areas with minor fire risk and limited area such as bathrooms within cabins, void spaces and tank compartments need not to be provided with fire detectors. 4.1.6 Switchboards shall be covered as defined in [5.2.7]. 4.1.7 As a minimum, an alarm shall immediately sound in the space where a detector has been activated and in the wheelhouse. This alarm can be an integrated part of the detector or be provided from the fire detection control unit.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 80

Part 5 Chapter 13 Section 11

intakes and extracts shall be designed with care to evacuate smoke effectively without impairing escape ways. All balancing ducts shall be provided with closing dampers operable from corridor side.

5.1 Fixed fire extinguishing system for machinery spaces 5.1.1 The requirements of HSLC Pt.4 Ch.10 in the rules for classification of HS, LC and NSC apply as amended and modified in [5.1.2] to [5.1.5]. 5.1.2 The fixed fire extinguishing system shall be type approved. 5.1.3 Any of the following systems will be accepted: — — — — —

water based system according to IMO Circ.668/728 CO2 system as specified in HSLC Pt.4 Ch.10 in the rules for classification of HS, LC and NSC a gaseous agent according to IMO MSC/Circ.848 a high expansion foam system (or equivalent) according to SOLAS an aerosol system according to IMO MSC/Circ. 1007.

5.1.4 All extinguishing systems shall be designed with 100% redundancy. Gas systems and aerosol systems shall have two independent discharges of extinguishing media. Water based systems shall have 100% redundancy in pump units, including control systems. A pressure accumulator with water storage capacity is not required. 5.1.5 Water based systems requiring fresh water shall be connected to dedicated water tanks with capacity for minimum 5 minutes operation for the largest space to be protected and automatic switch-over to seawater supply. Such systems can alternatively be provided with a manual switchover and fresh water supply tanks design for 15 minutes operation. Guidance note: Utility service tanks with low-level alarms can be considered as equivalent to dedicated tanks. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2 Other fire hazardous spaces or equipment 5.2.1 Storage rooms for explosives, including ammunition, decoy and similar equipment can be accepted when designed in accordance with Sec.15 or other equivalent standards. 5.2.2 Other weapon spaces and hazardous equipment shall be protected according to recognised standards. 5.2.3 Sonar cable installations can be accepted if solely located on open deck and not containing liquids with flashpoint under 100°C. Alternatively, designs complying with the requirements for seismic cable installations will be accepted. 5.2.4 Requirements for seismic cables containing flammable liquids: Storage space for seismic cables, gun deck and other areas where equipment containing flammable liquids are handled or stored, shall be protected by fixed fire extinguishing system. Special attention shall be given to vessels with a wooden gun deck above the steel deck, allowing for flammable liquid to collect in the closed space. In such cases the fixed fire extinguishing is also to protect the space below the wooden deck. Guidance note: One suitable fire extinguishing system is a low expansion foam system with the following capacity: —

2

3 litre/minute/m of streamer deck area

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 81

Part 5 Chapter 13 Section 11

5 Fire extinguishing systems and hazardous spaces

2

10 litre/minute/m of cable reels area.

Sufficient foam concentrate to ensure at least 20 minutes of foam generation. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.5 Any helicopter deck and hangars shall comply with IMO Res. A.855(20) or recognised naval standards. Refuelling facilities for fuel with flashpoint below 60°C shall in addition comply with rules for low flashpoint fuel systems in HSLC Pt.4 Ch.6 Sec.5 in the rules for classification of HS, LC and NSC. 5.2.6 Spaces intended for storage and handling of tender boats shall comply with requirements as for enclosed car ferries (ro-ro spaces). Relaxation of these requirements can be considered case by case for tenders using only fuel with flashpoint above 60°C. 5.2.7 All switchboards shall be enclosed by cabinets made of steel or materials having equivalent fire resistance. All switchboard cabinets shall be provided with an early fire detection system and a fixed fire extinguishing system suitable for such spaces. Guidance note: A modular gas fire extinguishing system is recommended. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.8 Diving systems, and outer areas surrounding diving systems, shall comply with the Society's document DNV-DSS-105 “Rules for Classification of Diving Systems”, or equivalent navy standard. It is advised that spaces for personal diving equipment also comply with relevant part of this standard.

6 Fire pumps, fire main and portable extinguishers 6.1 Fire pumps, fire main and fire hoses 6.1.1 The requirements of HSLC Pt.4 Ch.10 in the Rules for Classification of HS, LC and NSC apply as amended and modified in [6.1.2] to [6.1.5]. 6.1.2 The fire main, including supports, couplings and valves shall be made of fire resistant and corrosion resistant materials, such as CuNi. Other materials may be considered for vessels with single fire zone and limited survivability. Such materials shall comply with IMO Res. A.753(18), L3 (test in wet condition, 30 minutes). 6.1.3 An approved fire hose with jet or spray nozzles shall be connected to each hydrant at all times. Hydrant and hoses shall be installed in dedicated cabinets or clearly marked safety lockers. Fire hoses with a diameter exceeding 38 mm shall not be installed in accommodation areas unless the owner or navy administrator specifically defines another fire fighting philosophy. 6.1.4 All hydrants onboard shall have the same diameter. All couplings on nozzles, hoses and hydrants shall be interchangeable. A spanner shall be provided adjacent to each fire hydrant. 6.1.5 Water shall be immediately available from the hydrants. A continuously pressurised fire main, with start of at least one fire pump upon loss of pressure is considered to meet this requirement. Other equally reliable arrangement can be accepted.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 82

Part 5 Chapter 13 Section 11

—

6.2.1 The requirements of HSLC Pt.4 Ch.10 in the rules for classification of HS, LC and NSC apply as amended and modified in [6.2.2]. 6.2.2 At least three 12 kg dry powder or 9 l foam extinguisher, or equivalent types, shall be provided in corridors or stairways for each fire zone and each deck. In addition, at least one such extinguisher shall be 2 installed in public spaces above 30 m and any pantry. At least two extinguishers of suitable type shall be provided for the galley.

7 Sprinkler system 7.1 Sprinkler system 7.1.1 All public spaces, cabins and service spaces, storage rooms other than those required to have a fixed fire fighting system, and similar spaces shall be protected by a fixed sprinkler system meeting standards for fixed sprinkler systems for high speed-craft, IMO Res. MSC.44 (65). Areas of no fire risk and areas with minor fire risk and limited area such as void spaces and bathrooms within cabins need not to be provided with sprinklers. Guidance note: See IMO MSC/Circ.912, Interpretation of standards for fixed sprinkler system for high-speed craft (Res. MSC.44 (65)). ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7.1.2 Only automatic sprinkler systems are accepted. The system shall cover the largest area of the following: 2

— 75 m — area covered by four largest sprinkler heads — largest public space including largest space adjacent to this. The system need not be designed with redundancy in pumps or back-up pressure tank. Supply from emergency power is not required provided that all components (except piping, section valves and sprinklers) are located outside the protected area. 7.1.3 The fresh water supply shall be arranged as for water-based fixed fire extinguishing systems. Dedicated water tanks with capacity for minimum 5 minutes operation of demanded pumps shall be provided. 7.1.4 System plans shall be displayed at each operating station. Suitable arrangements shall be made for the drainage of water discharged when the system is activated. Alternatively, documentation shall be submitted to confirm that the sprinkler system can be operated for 30 minutes (with full pump capacity) without impairing the stability of the vessel.

8 Firefighter’s outfit 8.1 General 8.1.1 All vessels shall have at least three sets of firefighter's outfit as specified in the HSC code 7.10.3, per fire control zone. 8.1.2 Each of the breathing apparatus sets shall be provided with cylinders of 1 800 litres capacity. The total weight of one apparatus (including cylinder, valves and mask) shall not exceed 12.0 kg. Two spare

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 83

Part 5 Chapter 13 Section 11

6.2 Portable fire extinguishers

8.1.3 When more than one fire control zone is provided, the firefighter's outfits shall be divided between two fire stations placed at a safe distance from each other. The fire stations shall be clearly marked. On vessels with only one fire control zone and one locker for firefighter’s outfit, this locker shall have access from open deck or wheelhouse. 8.1.4 Each fire station shall be provided with 3 fire hoses, including nozzles and spanners, 2 portable extinguishers (12 kg powder or equivalent) and three emergency breathing apparatus (as defined by the IMO FSS code). 8.1.5 The arrangement of the fire stations shall be such that all the equipment is easily accessible and ready for immediate use. There shall be arrangements for hanging up protective clothing in a suspended position. 8.1.6 Other arrangement (type of equipment and numbers) may be accepted in lieu of the above when this is according to the standard of the navy in question. In these cases, the navy administration shall issue a request for acceptance of equivalent arrangements.

9 Additional fire protection (optional) 9.1 General 9.1.1 Vessels built and equipped in accordance with the requirements in this subsection will be given the additional class notation FIRENAV.

9.2 Accommodation 9.2.1 Three emergency breathing apparatus (as defined by the IMO FSS code) shall be provided along primary escape ways for each deck in each fire zone. 9.2.2 A high-pressure compressor suitable for filling cylinders for the breathing apparatus shall be installed. The compressor shall be driven by a separate diesel engine or from the emergency power plant and shall be placed in an easily accessible and safe place onboard. The capacity of the compressor shall be at least 300 litres/minute at 1 bar. Guidance note: When considering the compressor location it should be kept in mind that, when a fire has broken out onboard, the compressor must be operable and that the air to be compressed must be sufficiently clean for breathing purposes. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

9.2.3 The combat control station and the ship control shall be designed as a separate smoke ventilation zone with an independent ventilation supply. The station shall be structurally fire protected as a control station. Two means of escape shall be provided, each of them through independent ventilation zones.

9.3 Engine room 9.3.1 Combustion air shall be directly fed to the engines via dedicated steel ducts. Each engine shall have one independent set of air supply ducts.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 84

Part 5 Chapter 13 Section 11

cylinders shall be provided for each apparatus. All cylinders, apparatus and valves shall be of the same type. Apparatus with less capacity and less weight may be accepted if they are deemed to be more suitable for the intended service and more spare cylinders are provided.

9.3.3 In multi-engine installations, which are supplied from the same fuel source, means of isolating the fuel supply and spill piping to individual engines shall be provided. The means of isolation shall not affect the operation of the other engines and shall be operable from a position not rendered inaccessible by a fire in any of the engines. 9.3.4 Water drainage systems and filters to remove salt shall be included in the air intake. The air inlet quality (maximum salt content and particles) shall be in accordance with engine manufacturer's specification. Air intakes for vessels without service area restriction shall incorporate anti-icing systems preventing clogging of air intakes and louvers by ice. Anti-icing systems on vessels with service area restrictions will be considered depending on operating area. 9.3.5 Fire fighting of machinery spaces shall be possible when two or more propulsion or power generation machines are enclosed in same compartment with the machinery running at reduced power (30%) for 20 minutes. 9.3.6 In the case that two or more propulsion or power generating machines are installed in the same compartment, machinery shall be so designed that release of fire fighting agent does not damage machinery. This shall be verified through testing as far as is practicable.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 85

Part 5 Chapter 13 Section 11

9.3.2 Engine air intakes and exhaust outlets for propulsion engines shall be designed for release of fire extinguishing agent in the engine machinery space without shutting down main engines.

1 General 1.1 General 1.1.1 The requirements for the arrangement of life saving appliances in this section are based on naval standards and applies to vessels with class notation Naval or Naval support(EVAC). 1.1.2 Life-saving appliances and arrangements shall enable abandonment of the vessel in 10 minutes. 1.1.3 Except where otherwise provided in this section, the life-saving appliances required by this section shall meet the detailed specifications set out in the International Life-Saving Appliances (LSA) Code (1996, as amended) and be approved by the Society. 1.1.4 Before giving approval to life-saving appliances and arrangements, the Society shall ensure that such life saving appliances and arrangements: 1) 2)

Are tested to confirm that they comply with the requirements of this section, and in accordance with the recommendations listed in IMO res. A.689(17) as amended, or Have successfully undergone, to the satisfaction of the Society, evaluation and tests which are substantially equivalent to those recommendations.

1.1.5 Before giving approval to novel life-saving appliances or arrangements, the Society shall ensure that such appliances or arrangements: 1) 2)

Provide safety standards at least equivalent to requirements of this chapter and have been evaluated and tested in accordance with the recommendations listed in IMO res. A.520(13), or as it may be amended. Have successfully undergone, to the satisfaction of the Society, evaluation and tests which are substantially equivalent to those recommendations.

1.1.6 Before accepting life-saving appliances and arrangements that have not been previously approved by the Society, the Society shall be satisfied that life-saving appliances and arrangements comply with the requirements of this section. 1.1.7 Except where otherwise provided in this section, life- saving appliances required by this section for which detailed specifications are not included in the LSA Code, shall be to the satisfaction of the Society. 1.1.8 The Society requires life-saving appliances to be subjected to such product tests as are necessary to ensure that the life-saving appliances are manufactured to the same standards as the approved prototype. 1.1.9 Procedures adopted by the Society for approval shall also include the conditions whereby approval would continue or would be withdrawn. 1.1.10 The Society may determine the period of acceptability of life-saving appliances that are subject to deterioration with age. Such life-saving appliances shall be marked with a means of determining their age or the date by which they shall be replaced.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 86

Part 5 Chapter 13 Section 12

SECTION 12 SAFE EVACUATION OF PERSONNEL

For the purposes of this section, unless expressly provided otherwise: 1.2.1 Terms 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13)

Anti exposure suit is a protective suit designated for use by crew in case of evacuation, and when working in exposed positions on deck. Climbing net is a net used for disembarkation of personnel to the survival craft and for the recovery of persons in the water. Detection is the determination of the location of survivors or survival craft. Embarkation ladder is the ladder provided at survival craft embarkation stations to permit safe access to survival craft after launching. Embarkation station is the place from which a survival craft is boarded. An embarkation station may also serve as a muster station, provided there is sufficient room, and the muster station activities can safely take place there. Float-free launching is that method of launching a survival craft whereby the craft is automatically released from sinking vessel and is ready for use. Free-fall launching is that method of launching a survival craft whereby the craft with its complement of persons and equipment on board is released and allowed to fall into the sea without any restraining apparatus. Immersion suit is a protective suit that reduces the body heat-loss of a person wearing it in cold water. Inflatable appliance is an appliance that depends upon non-rigid gas-filled chambers for buoyancy and that is normally kept deflated until ready for use. Launching appliance or arrangement is a means of transferring a survival craft or rescue boat from its stowed position safely to the water. LSA Code is the International Life-Saving Appliances (LSA) Code as adopted by IMO resolution MSC.48(66) as it may be amended. Novel life-saving appliance or arrangement is a life-saving appliance or arrangement that embodies new features not fully covered by the provisions of this chapter but that provides an equal or higher standard of safety. Muster station is a place in the vicinity of the embarkation station and that permits ready access for the 2 crew to the embarkation stations unless in the same location. The area should be at least 0.35 m per crew member. Guidance note: The muster station may be considered as the total accessible area adjacent to the embarkation station. The muster areas should be described in the vessel's operational procedures. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

14) 15) 16) 17)

Rescue boat is a boat designed to assist and rescue persons in distress and to marshal survival craft. Retrieval is the safe recovery of survivors. Retro-reflective material is a material that reflects in the opposite direction a beam of light directed on it. SOLAS 1996 amendments is International Convention for the Safety of Life at Sea, 1974 as amended in June 1996 by IMO resolution MSC.47(66). 18) Survival craft is a craft capable of sustaining the lives of persons in distress from the time of abandoning the vessel. 19) Thermal protective aid is a bag or suit made of waterproof material with low thermal conductance.

1.3 Exemptions 1.3.1 The Society may exempt individual vessels or classes of vessel from the requirements of this section if the requirements are considered unreasonable or unnecessary in respect to the nature of the operation.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 87

Part 5 Chapter 13 Section 12

1.2 Definitions

1.4 Special requirements for class notation Naval support 1.4.1 The requirements given for main class shall apply 1.4.2 The navy may decide to deviate from [1.4.1]. In this case the principle of equivalent safety shall be applied as far as reasonably practicable, and shall be agreed upon by the Society. In case of such deviations of the conditions of Sec.1, [6.1] shall apply.

1.5 Documentation requirements 1.5.1 Documentation shall be submitted as required by Table 1. Table 1 Documentation requirements Object safety, general life-saving appliances

pilot transfer arrangement

Documentation type

Additional description

Info

G050 - safety plan

AP

G160 - lifesaving arrangement plan

AP

G140 - muster list and emergency instructions

AP

Z030 - arrangement plan

plan and side view, andcross section.

AP

1.5.2 For general requirements to documentation, including definition of the Info codes, see Pt.1 Ch.3 Sec.2. 1.5.3 For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

2 Communications 2.1 Communication 2.1.1 Naval surface vessels shall be provided with the following radio life-saving appliances. 1) 2) 3)

At least three two-way VHF radiotelephone apparatuses shall be provided on every vessel. Such apparatus shall conform to performance standards not inferior to those adopted by IMO in resolution A.809(19), or as it may be amended. At least one radar transponder shall be carried on each side of every vessel. Such radar transponders shall conform to performance standards not inferior to those adopted by IMO in resolution A.802(19), or as it may be amended. The storage of radar transponders may be protected for military purposes. The radar transponders shall be stowed in such locations that they can be rapidly placed in any one of the liferafts. Alternatively, one radar transponder shall be stowed in each survival craft.

2.1.2 Naval surface vessels shall be provided with the following on-board communications and alarm system: 1) 2)

An emergency means comprising either fixed or portable equipment or both for two-way communications between emergency controls stations, muster and embarkation stations and strategic positions on board. A general emergency alarm system complying with the requirements of 7.2.1 in the LSA Code shall be used for summoning crew to muster stations and to initiate the actions included in the muster list. The system shall be supplemented by either a public address system or other suitable means of

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 88

Part 5 Chapter 13 Section 12

When individual vessels or classes of vessel receive such dispensation they shall not proceed more than 20 nautical miles from the nearest land.

2.2 Signalling equipment 2.2.1 All vessels shall be provided with a portable daylight signalling lamp which is available for use at each muster station at all times and which is not dependent on the vessel’s main emergency source of electrical power. 2.2.2 Naval surface vessels shall be provided with not less than 12 rocket parachute flares, complying with the requirements of 3.1 in the LSA code stowed in or near the bridge.

3 Personal life-saving appliances 3.1 Lifebuoys 3.1.1 Where crew have access to exposed decks under normal operating conditions, at least one lifebuoy on each side of the vessel capable of quick release from the control compartment and from position at or near where it is stowed, shall be provided with a self-activating light and a self-activating smoke signal. The positioning and securing arrangements of the self-activating smoke signal shall be such that it cannot be released or activated solely by the accelerations produced by collisions or groundings. 3.1.2 At least one lifebuoy shall be provided adjacent to each normal exit from the vessel and on each open deck to which crew have access, subject to a minimum of two being installed. 3.1.3 Lifebuoys fitted adjacent to each normal exit from the vessel shall be fitted with buoyant lines of at least 30 m in length. 3.1.4 Not less than half the total number of lifebuoys shall be fitted with self-activating lights. However, the lifebuoys provided with self-activating lights shall not include those provided with lines in accordance with [3.1.3]. 3.1.5 The total number of lifebuoys shall be 2 for every 20 m of vessel lengths or part thereof with a minimum of 4. 3.1.6 Lifebuoys and buoyant lines shall comply with the requirements of 2.1.1 in the LSA Code.

3.2 Lifejackets 3.2.1 A lifejacket complying with the requirements of 2.2.1 or 2.2.2 in the LSA Code or an equivalent military standard shall be provided for every person on board the vessel and, in addition: 1) 2) 3)

Every vessel shall carry lifejackets for not less than 20% of the total number of persons on board. These lifejackets shall be stowed in conspicuous places on deck or at muster stations. A sufficient number of lifejackets shall be carried for persons on watch and for use at remotely located survival craft and rescue boat stations. All lifejackets shall be fitted with a light, which complies with the requirements of 2.2.3 in the LSA Code or an equivalent military standard.

3.2.2 Lifejackets shall be so placed as to be readily accessible and their positions shall be clearly indicated.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 89

Part 5 Chapter 13 Section 12

communication. The system shall be operable from the combat information centre, bridge and technical control room.

3.3.1 An anti exposure suit, of an appropriate size, complying with the requirements of 2.4 in the LSA Code or an equivalent military standard shall be provided for every person assigned to crew the rescue boat. 3.3.2 Immersion suits in compliance with the requirements of 2.3 in the LSA Code, or an equivalent military standard shall be provided for 110% of the number of persons the vessel is certified to carry.

4 Muster list, emergency instructions and manuals 4.1 General 4.1.1 Clear instructions to be followed in the event of an emergency shall be provided for each person on board. 4.1.2 Muster lists complying with the requirements of regulation III/37 of the SOLAS 1996 amendments shall be exhibited in conspicuous places throughout the vessel, including the combat information centre, bridge and technical control room, engine-room and crew accommodation spaces. 4.1.3 Illustrations and instructions in appropriate languages shall be posted in crew accommodation spaces and be conspicuously displayed at muster stations, to inform the crew of — — — —

their muster station the essential actions they shall take in an emergency the method of donning lifejackets the method of donning the anti-exposure suits. Guidance note: At least English and the national language is recommended. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.4 A training manual complying with the requirements of SOLAS 1996 regulation III/35 shall be provided in each crew messroom and recreation room. Guidance note: At least English and the national language is recommended. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5 Operating instructions 5.1 General 5.1.1 Posters or signs shall be provided on or in the vicinity of the survival craft and their launching controls and shall: — illustrate the purpose of controls and the procedures for operating the appliance and give relevant instructions and warnings — be easily seen under emergency lighting conditions 1) — use symbols in accordance with the recommendations of IMO . 1)

Refer to the symbols related to life-saving appliances and arrangements, adopted by IMO by resolution A.760(18) or as it may be amended.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 90

Part 5 Chapter 13 Section 12

3.3 Immersion and anti-exposure suits

6.1 General 6.1.1 Survival craft shall be securely stored outside and as close as possible to the accommodation and embarkation stations. The stowage shall be such that each survival craft can be safely launched in a simple manner and remain secured to the vessel during and subsequent to the launching procedure. The length of the securing lines and the arrangements of the bowsing lines shall be such so as to maintain the survival craft suitably positioned for embarkation. The Society may permit the use of adjustable securing and or bowsing lines at exits where more than one survival craft is used. The securing arrangements for all securing and bowsing lines shall be of sufficient strength to hold the survival craft in position during the embarkation process. 6.1.2 Survival craft may be stored under deck, provided means are taken to automatically release the deckhatches to enable float free launching should the vessel sink. The requirements given in [1.1.2] shall be fulfilled. 6.1.3 So far as is practicable, survival craft shall be distributed in such a manner that there is an equal capacity on both sides of the vessel. 6.1.4 The launching procedure for inflatable liferafts shall, where practicable, initiate inflation. Where it is not practicable to provide automatic inflation of liferafts, the total evacuation time shall not exceed the time given in [1.1.2]. 6.1.5 Survival craft shall be capable of being launched in all operational conditions and in all specified damage conditions. 6.1.6 Survival craft launching stations shall be in such positions so as to ensure safe launching, having particular regard to clearance from the propeller or water jet and steeply overhanging portions of the hull. 6.1.7 During preparation and launching, the survival craft and the area of water into which it shall be launched shall be adequately illuminated by the lighting supplied from the main and or emergency sources of electrical power required by Sec.8. 6.1.8 Means shall be available to prevent any discharge of water on to survival craft when launched. 6.1.9 Each survival craft shall be stowed: — so that neither the survival craft nor its stowage arrangements will interfere with the operation of any other survival craft or rescue boat at any other launching station — in a state of a continuous readiness — fully equipped — as far as practicable, in a secure and sheltered position and protected from damage by fire and explosion. 6.1.10 Every liferaft shall be stowed with its painter permanently attached to the vessel and with a floatfree arrangement complying with the requirements of 4.1.6 in the LSA code so that, as far as practicable, the liferaft floats free and inflates automatically should the vessel sink. 6.1.11 Rescue boat shall be stowed: — in a state of continuous readiness for launching in not more than 5 min — in a position suitable for launching and recovery — so that neither the rescue boat nor its stowage arrangements will interfere with the operation of survival craft at any other launching station.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 91

Part 5 Chapter 13 Section 12

6 Survival craft stowage

7 Survival craft and rescue boat embarkation and recovery arrangements 7.1 General 7.1.1 Embarkation stations shall be readily accessible from accommodation and work areas. 7.1.2 Evacuations routes, exits and embarkation points shall comply with the requirement in Sec.10 [7.1]. 7.1.3 Alleyways, stairways and exits giving access to the muster and embarkation station shall be adequately illuminated by lighting supplied from the main and emergency source of electrical power required by Sec.8. 7.1.4 Where the disembarkation height in intact and damaged condition exceeds 4.5 m, climbing ladders or nets shall be installed on both sides of the vessel. 7.1.5 Rescue boat embarkation arrangements shall be such that the rescue boat can be boarded and launched direct from the stowed position and recovered rapidly when loaded with its full complement of crew, rescued persons and equipment.

8 Line-throwing appliance 8.1 General 8.1.1 A line-throwing appliance complying with the requirements of 7.1 in the LSA Code shall be provided.

9 Operational readiness, maintenance and inspections 9.1 General The ship shall have a maintenance and inspection plan that should contain all the elements from[9.1] to [9.3.4]

9.2 Operational readiness 9.2.1 Before the vessel leaves port and at all times at sea, all life-saving appliances shall be in order and ready for immediate use.

9.3 Maintenance 9.3.1 Instructions for on-board maintenance of life-saving appliances complying with the requirements of regulation III/36 of SOLAS 1996 shall be provided and maintenance shall be carried out accordingly. 9.3.2 The Society may accept, in lieu of the instructions required by [9.2.1], a shipboard planned maintenance programme, which includes the requirements of regulation III/36 of SOLAS 1996.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 92

Part 5 Chapter 13 Section 12

6.1.12 Rescue boats and survival craft shall be secured and fastened to the deck so that will withstand at least 3 g in all principal directions or two times the defined design accelerations, whichever is the largest.

9.3.4 Spares and repair equipment Spares and repair equipment shall be provided for life-saving appliances and their components, which are subject to excessive wear or consumption and shall be replaced regularly. 9.3.5 Weekly inspection The following tests and inspections shall be carried out weekly: — all survival craft, rescue boats and launching appliances shall be visually inspected to ensure that they are ready for use — all engines in rescue boats shall be run ahead and astern for a total period of not less than 3 minutes provided the ambient temperature is above the minimum temperature required for starting the engine — the general emergency alarm system shall be tested. 9.3.6 Monthly inspections Inspections of the life-saving appliances, including survival craft equipment, shall be carried out monthly, using the checklist required by regulation III/52.1 of SOLAS 1996 to ensure that they are complete and in good order. A report of the inspection shall be entered in the logbook.

9.4 Servicing on inflatable liferafts, inflatable lifejackets and inflated rescue boats 9.4.1 Every inflatable liferaft and inflatable lifejacket shall be serviced: — at intervals not exceeding 12 months 1) — at an approved servicing station , which is competent to service them, maintains proper servicing facilities and uses only properly trained personnel. 1)

Refer to the Recommendation on conditions for the approval of servicing stations for inflatable liferafts, adopted by IMO by resolution A.761(18) or as it may be amended.

9.4.2 All repairs and maintenance of inflated rescue boats shall be carried out in accordance with the manufacturer’s instructions. Emergency repairs may be carried out on board the vessel, however, permanent repairs shall be effected at an approved servicing station. 9.4.3 Periodic servicing of hydrostatic release units Hydrostatic release units shall be serviced: — at intervals not exceeding 12 months — at an approved servicing station, which is competent to service them, maintains proper servicing facilities and uses only properly trained personnel. 9.4.4 Provided service experience has shown that longer interval than given in [9.3.1] to [9.3.3] is acceptable, the Society may accept longer intervals between servicing.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 93

Part 5 Chapter 13 Section 12

9.3.3 Maintenance of falls Falls used in launching shall be turned end-for-end at intervals of not more than 30 months and be renewed when necessary due to deterioration of the falls or at intervals of not more than five years, whichever is the earlier.

10.1 Vessels with length less than 30 m 10.1.1 The vessel shall be provided with a least 2 survival craft each with a capacity of 100% of the number of persons the vessel is certified to carry. 10.1.2 If a person in the water can be picked up by the vessel, a rescue boat will not be required.

10.2 Vessels with length above 30 m 10.2.1 The vessel shall be provided with survival craft capacity of minimum 150% of the number of persons the vessel is certified to carry. The survival craft shall be equally distributed at both sides of the vessel and spread out over the vessel's length. The location of the survival craft shall assure that 100% of the number of persons the vessel is certified to carry can be used on one side after damage anywhere on the vessel as defined in Sec.5. 10.2.2 If the survival craft can be moved from one side to another, then the vessel shall be provided with survival craft on each side for 50% of the number of persons the vessel is certified to carry and any combination of between 100% and 50% on each side, dependant on the number of survival craft that can be moved to either side, as given in Table 2. Table 2 Survival craft and rescue boats Minimum survival craft capacity on each side

Movable survival craft capacity

Total survival craft capacity

50%

50%

150%

60%

40%

160%

70%

30%

170%

80%

20%

180%

90%

10%

190%

100%

0%

200%

10.2.3 A minimum of 1 rescue boat shall be provided. The rescue boat shall meet the requirement in the LSA Code as amended for fast rescue boats. The Society may exempt from the requirement to carry a fast rescue boat if it considers the vessel’s manoeuvrability makes it possible to retrieve a person over board with a rescue boat as specified in the LSA Code.

11 Additional requirements for equipment 11.1 Liferafts 11.1.1 Liferafts shall be automatically self-righting or canopied reversible liferafts in accordance with MSC/ Circ.809. 11.1.2 Life-raft equipment shall be to the satisfaction of the Society.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 94

Part 5 Chapter 13 Section 12

10 Survival craft and rescue boats

11.2.1 The size of climbing nets on vessels with length above 30 m shall be at least 4 m wide and have a depth not less than the intact freeboard height, whilst for smaller vessels the net shall be at least 2 m wide and have depth not less than the intact freeboard height. The following requirements apply to both sizes: — — — — — — —

the net shall be made from coir or manila rope frame rope at least 25 mm with tensile strength 10 kN (minimum) net rope at least 20 mm with tensile strength 3 kN (minimum) size of squares maximum 300 × 300 mm horizontally 3 planks of size 60 mm × 60 mm × 4 m shall be sewn in at the top, middle and bottom an iron bar with 25 mm diameter × 4 m shall be sewn in at the bottom at the top end of the net maximum 5 pieces of rope size 30 mm × 3 m nylon, each of tensile strength 20 kN (minimum) shall be fastened at 1 m interval.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 95

Part 5 Chapter 13 Section 12

11.2 Climbing nets

1 General 1.1 Application 1.1.1 Vessels with class notation Naval or Naval support(RADHAZ) shall comply with the requirements in this section cover aspects relating to electromagnetic radiation in the frequency band generally from 0 Hz (DC) up to 300 GHz generated by on board sources and representing radiation hazards to personnel, fuel or ordnance. Optical links e.g. fibre optics are also covered. Guidance note 1: It has been recommended to include also DC phenomena e.g. electrostatic discharges. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--Guidance note 2: ‘STANAG; the operational RADHAZ manual AECP-2 and/or national requirements may apply. In instances these requirements are different, the most stringent requirements shall apply. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2 Definitions 2.1 Terms 2.1.1 Average power density. The power of radio frequency field per unit cross sectional area per square 2 meter (W/m ) and averaged over a given period. 2.1.2 Basic restrictions. Restrictions on exposure to time-varying electric, magnetic and electromagnetic fields that are based directly on established health effects. 2.1.3 Contact current. Time varying current flowing through an individual touching a conductive object (through hand or wrist). 2

2.1.4 Current density. Current divided by the cross-sectional area of the conductor (A/m ). 2.1.5 General public exposure. Individuals of all ages and varying health status, and may include particularly susceptible groups or individuals being unaware of their exposure to electromagnetic fields. 2.1.6 Limb current. The contact or induced current through arms or legs. For the contact current, the person is supposed to touch an object by flat hand e.g. a railing, bulkhead or deck. For the induced current, the person shall be standing in an upright position. 2.1.7 Occupational exposed. Adults who are generally exposed under known conditions and are trained to be aware of potential risks and to take appropriate precautions. 2.1.8 Pulsed radio frequency field. Radio frequency electric and magnetic fields that are produced by amplitude modulating a continuous-wave carrier at a known pulse repetition frequency with a controlled duty factor. 2.1.9 RADHAZ. Radiation hazards to personnel, ordnance and to fuel.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 96

Part 5 Chapter 13 Section 13

SECTION 13 RADIATION HAZARDS

2.1.11 Re-radiated field. Radio frequency fields resulting from currents induced in a secondary predominantly conducting object by electromagnetic waves incident on that object from one or more primary radiating structures or antenna. 2.1.12 Safety distance. Minimum distance to the transmitter at which the reference level for the relevant category of personnel is not exceeded, measured on the axis of the main beam. 2.1.13 Specific absorption rate (SAR). The time rate at which radio frequency energy is imparted to an element of biological body mass. Average SAR in a body is the time rate of the total energy absorbed divided by the total mass of the body. SAR is expressed in units of watts per kilogram (W/kg). Specific absorption (SA) refers to the amount of energy absorbed over an exposure time period and is expressed in units of Joules per kilogram (J/kg).

3 Documentation 3.1 Plans and particulars 3.1.1 The following plans and particulars shall be submitted for approval: — RADHAZ control document containing relevant technical RADHAZ information. This includes at least analysis of transmitter arrangement and equipment properties limit values, guidelines to workforce, technical solutions, drawings and test results. Guidance note: RADHAZ analysis for the entire vessel depends on electromagnetic environmental data at the locations and sites that the systems will be exposed to. Therefore a list of intentional EM emitters (location, output power, frequency, modulation and hours of operation and operating modes.) should be analysed. The analysis should justify the need for the zones, based on what equipment will be installed and the equipment’s electrical properties. Operational documents, containing the results of the RADHAZ analysis should be kept on board and be updated if and when other equipment is put in operation. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

— The RADHAZ test plan shall describe details for the harbour acceptance tests (HAT). — A RADHAZ marking plan shall be produced showing areas to be marked by recognised standard of RADHAZ signs.

4 Design principles 4.1 General 4.1.1 The design of the vessel shall ensure that all relevant systems can be operated separately or concurrently (if necessary) and at specified performance, without radiation hazards to vessel, its complement, fuels or ordnance. 4.1.2 RADHAZ protection shall be provided by means of careful location of radiating antennas, denial of entry for personnel and allocation of ordnance or fuel to areas with acceptable low power electromagnetic fields. Attention shall be paid to effects from re-radiated fields.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 97

Part 5 Chapter 13 Section 13

2.1.10 Reference levels. These levels are provided for practical exposure assessment purposes to determine whether the basic restrictions are likely to be exceeded.

4.1.4 When possible, physical controls shall be used rather than administrative controls. Physical controls include interlocks, fences and locks. Administrative controls include signs, operational procedures and training.

4.2 Prevention of auto ignition 4.2.1 Fuels and electro initiated explosive devices shall be handled in a safe manner. The level of electromagnetic radiation shall be acceptably low to prevent auto ignition at the places where fuels and ordnance are kept. Guidance note: a)

The level of radiated power and field strength should be limited to safe values acceptable to the appropriate authority.

b)

For ordnance, see MIL-STD 464A and/or AECTP-250 Leaflet 258 combined with AECTP-500 Leaflet 508/3.

c)

For fuels such as diesel oil there exist no practical limit. Operational procedures should be implemented, e.g. no operation of any powerful radio transmitters during fuelling operations. For jet propellants, the limit values given in MIL STD 1399 A, section 408 and operational handbook OP 3565 may be applied.

d)

For ammunitions, see also Sec.15. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4.3 Prevention of personnel exposure 4.3.1 Protection against harm to personnel shall be achieved by identifying sources and by estimating (or measuring) the relevant characteristics. — The applicable reference levels for the system shall be determined, see Table 2, and the safety distance shall be defined. — For the purpose of demonstrating compliance with the basic restrictions, the reference levels for electric and magnetic fields should be considered separately and not additively. — In the situations of simultaneous exposure to fields of different frequencies, these exposures are to be added and the reference levels should be met. In case of exceeding the reference levels, the basic restrictions shall be met. See guidance note c) below. — Physical and or administrative controls shall be defined. Guidance note: a)

Regarding evaluation and control of personnel exposure to radio frequency and static magnetic fields the limit values and procedures specified in International Commission on Non-Ionizing Radiation Protection: ICNIRP 1998 EMF Guidelines, ICNIRP 2010 Guidelines in the LF range and ICNIRP 2009 Guidelines on static magnetic fields have been adopted.

b)

See ACEP-2B, NATO Naval Radio and Radar Radiation Hazard Manual.

c)

Simultaneous exposure to multiple frequency fields:

For electrical stimulation and frequencies up to 10 MHz:

For thermal effects above 100 kHz:

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 98

Part 5 Chapter 13 Section 13

4.1.3 In situations of simultaneous exposure to fields of different frequencies, these exposures are additive in their effects. Additivity shall be examined separately for the effects of thermal and electrical stimulation, and the basic restrictions shall be met.

Part 5 Chapter 13 Section 13

For induced current density and electrical stimulation effects up to 10 MHz:

and

For thermal considerations relevant above 100 kHz:

and

Limb current and contact current:

Ji

=

Current density induced at frequency i

JL,i

=

Induced current density restriction at frequency i

SARi

=

SAR caused by exposure at frequency i

SARL

=

SAR limit in Table 1

SL

=

Power density limit

Si

=

Power density at frequency i

Ei

=

Electric field strength at frequency i

EL,i

=

Electric field strength limit in Table 2

Hj

=

Magnetic field strength at frequency j

HL,j

=

Magnetic field strength limit at frequency i in Table 2

a

=

610V/m for occupational exposure; 87V/m for public exposure

b

=

24.4A/m for occupational exposure; 5A/m for public exposure

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 99

=

610/f V/m for occupational exposure; 87/√f V/m for public exposure (f in MHz)

d

=

1.6/f A/m for occupational exposure; 0.73/f A/m for public exposure (f in MHz)

Ik

=

Limb current component at frequency k

IL,k

=

Limb current limit in Table 3

In

=

Contact current component at frequency n

IC,n

=

Contact current component limit in Table 3 ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4.3.2 The basic dosimetric limit of radio frequency exposure in the frequency range of 100 kHz to 10G Hz is whole-body specific absorption rate (SAR) of 0.4 W/kg for occupational exposure and 0.08 W/kg for general public exposure respectively. Below 100 kHz internal current density resulting in electro-stimulation of biological tissue is the basic dosimetry parameter. Basic restrictions are given in terms of measurable field components i.e. reference levels as a convenient correlation to SAR. Compliance with the reference levels will ensure compliance with the relevant basic restrictions. Guidance note: a)

This SAR value of 0.4W/kg is a factor of ten times lower than the threshold for the most sensitive reproducible effect reported in laboratory animals. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 100

Part 5 Chapter 13 Section 13

c

Frequency

Current density for head and trunk 2 (mA/m ) (rms)

Whole-body average SAR (W/kg)

Localized SAR, head and trunk (W/kg)

Localized SAR, limbs (W/kg)

occupational

public

occupational

public

occupational

public

occupational

public

≤ 1 Hz

40

8

-

-

-

-

-

-

1-4 Hz

40/f

8/f

-

-

-

-

-

-

4 Hz-1 kHz

10

2

-

-

-

-

-

-

1-100 kHz

f/100

f/500

-

-

-

-

-

-

0.1-10 MHz

f/100

f/500

0.4

0.08

10

2

20

4

0.01-10 GHz

-

-

0.4

0.08

10

2

20

4

Notes: a)

f is the frequency in Hz.

b)

Because of electrical inhomogeneity of the body, current densities in terms of RADHAZ to human beings should be 2 averaged over a cross-section of 1 cm perpendicular to the current direction.

c)

For frequencies up to 100 kHz, peak current density values can be obtained by multiplying the rms value by √ 2. For pulses of duration tp the equivalent frequency to apply in basic restrictions should be calculated as f= 1/(2tp)

d)

For pulses of duration tp the equivalent frequency to apply in the basic restrictions should be calculated as f = 1/ (2tp). Additionally for pulsed exposures in the frequency range 0.3 to 10 GHz and for localized exposure of the head, an additional basic restriction is recommended. The SA should not exceed 10 mJ/kg for operators and 2 mJ/kg for general public over 10 g tissue.

e)

All SAR values are to be averaged over a 6 minutes period.

f)

Localized SAR averaging mass is any 10 g contiguous tissue; the maximum SAR so obtained should be the value used for the estimation of exposure.

g)

In this context trunk means body minus head and limbs.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 101

Part 5 Chapter 13 Section 13

Table 1 Basic restrictions for time-varying electric and magnetic fields

E-field strength (V/m)

H-field strength (A/m)

Equivalent plane wave 2 power density (W/m )

Frequency occupational ≤ 1 Hz 1-8 Hz

-

public

occupational

-

20000

public

occupational

public

-

-

3.2 · 10 / f

-

-

-

-

10

2

5

4

1.63 · 10 5

5000

1.63 · 10 / f

3.2 · 10 2

4

4

8-25 Hz

20000

5000

2 · 10 / f

4000 / f

25-50 Hz

500000 / f

5000

800

160

50-300 Hz

500000 / f

5

2.5 · 10 / f

800

160

300-400 Hz

500000 / f

2.5 · 10 / f

5

2.4 · 10 / f

5

5

160

5

2

4

400-3 kHz

500000 / f

2.5 · 10 / f

2.4 · 10 / f

6.4 · 10 / f

3 kHz-10 MHz

170

83

80

21

10-400 MHz

61

28

0.16

0.073

400-2000 MHz 2-300 GHz

3·10

-3

1/2

·f

137

1.375·10

-3

1/2

·f

8·10

61

-6

1/2

·f

-6

3.7·10

0.36

1/2

7

·f

0.16

8

f / (4·10 )

f / (2·10 )

50

10

Notes: 1)

f as indicated in Hz units.

2)

Provided the basic restricts are met and adverse indirect effects can be excluded, field strength values can be exceeded.

3)

For frequencies between 100 kHz and 10 GHz, Seq, E and H are to be averaged over a 6 minutes period.

4)

For peak values at frequencies up to 100 kHz, see Table 1 foot note c.

5)

Between 100 kHz and 10 MHz, peak values for the field strengths are obtained by interpolation from 1.5-fold peak at 100 kHz to the 32-fold peak at 10 MHz. For frequencies exceeding 10 MHz, it is suggested that the peak equivalent plane wave power density, as averaged over the pulse width, does not exceed 1000 times the Seq. restrictions, or that the field strength does not exceed 32 times the field strength exposure levels.

6)

For frequencies exceeding 10 GHz, Seq, E and H are to be averaged over any 68/f

7)

No E-field value is provided for frequencies <1 Hz, which are effectively static electric fields. Electric shock from low impedance sources is prevented by established electrical safety procedures for such equipment.

8)

These guidelines are subject to revisions and will be updated as advances are made in identifying the adverse health effects of time-varying electric, magnetic and electromagnetic fields.

9)

The magnetic field has been specified by the magnetic field strength H. The magnetic flux density B can be used

2

2

2

2

instead. The two quantities are related by expression B =

1.05

-min period (f in GHz).

μH where μ = 4 π x 10-7 (SI-units)

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 102

Part 5 Chapter 13 Section 13

Table 2 Reference levels for exposure of time-varying electric and magnetic fields (rms values)

Part 5 Chapter 13 Section 13

Table 3 Reference levels for time varying currents from conductive objects Maximum contact current (mA) Frequency

Contact currents occupational

public

1.0

0.5

≤ 2.5 kHz 2.5-100 kHz

Current induced in any limb

4·10

-4

· f (f in Hz)

2·10

-4

occupational

public

100

45

· f (f in Hz)

100 kHz-10 MHz

40

20

10-110 MHz

40

20

4.3.3 The static magnetic flux density shall not exceed: occupational — Head and trunk: 2T — Limbs: 8T public — Any part of the body: 400mT. 4.3.4 Persons using lasers and may be exposed to laser radiations above maximum permissible exposure must use approved safety eye wear and/or skin protection. Guidance note: a)

The Maximum Permissible Exposure (MPE) is a limit value depending on wavelength and exposure time, and is different for eye and skin exposures. The MPE values are stated by National Regulative Bodies.

b)

Lasers are divided into classes i.e. 1, 1M, 2, 2M, 3R, 3B and 4. Work with lasers belonging to class 1, 1M, 2, 2M, 3R does not normally entail any risk of radiation injury and are considered as safe so long as the radiation is not concentrated with aid of beam collecting optics, e.g. binoculars. Class 3B and 4 may damage the eyes and in certain cases also the skin. Class 4 can also cause exposed material to ignite. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5 Installation 5.1 General 5.1.1 Antenna feeder cables between antenna tuner(s) and antenna shall be safely arranged. Guidance note: The antenna tuner for HF should be arranged as close as possible to the antenna and shall not be routed through below deck space. High-frequency (HF) energy from transmitting systems is generated in the transmitter cabinet, and conducted to the antenna tuner by a coaxial cable. From the antenna tuner to the feed point of the antenna, a single wire is used. This wire will act as a part of the antenna and radiate high levels of HF-energy. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.1.2 All decks and bulkheads encapsulating shielded compartments to protect from RADHAZ shall normally be assembled by continuous welding or soldering. Spot welding, riveting or other assembly techniques will not provide acceptable shielding effectiveness. However, alternative methods giving the same or better performance may be considered.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 103

Guidance note: A power level below 10 mW as maximum will normally be considered as intrinsically safe, such that additional precautions are deemed unnecessary. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2 Marking 5.2.1 RADHAZ areas with levels exceeding those values listed in Table 1 to Table 3 shall be marked according to a recognised standard of RADHAZ signs. Warning signboards shall be posted giving information on restricted occupancy. In addition to type and emission levels of electromagnetic signal, instructional or warning statements shall be inserted on the sign. Guidance note: The basic formats should confirm with national military standards. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.2 RADHAZ warning signs are required at all access points to areas mentioned in [5.2.1]. Areas in which the basic restrictions for general public exposure are exceeded shall be marked at the entrance with an appropriate warning sign. Example of a warning sign:

The upper triangle has yellow/red colour. The symbol is in black on white background. The lower triangle has white colour with black text on. The subtitle shall describe the danger and give instructions, for example:

5.2.3 In areas where access to levels greater than 10 times the basic restrictions for general public exposure may exist, warning signs alone do not provide adequate protection. Other warning devices such as flashing lights, audible signals, or physical controls such as barriers or interlocks will be required.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 104

Part 5 Chapter 13 Section 13

5.1.3 Additional precautions shall be taken for fibre optic equipment in terms of shielding, such that stray optical radiation cannot result in inadvertent ignition of flammables or electro initiated explosive devices.

Part 5 Chapter 13 Section 13

6 Testing 6.1 Harbour acceptance tests (HAT) for the vessel 6.1.1 Measurements shall verify that reference levels i.e. the planned levels have not been exceeded.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 105

1 General 1.1 Application 1.1.1 Vessels with class notation Naval or Naval support(FMC) shall comply with the requirements given in this section, covering the vessel’s systems ability to function under the influence of electromagnetic interference or interactions with all kinds of electrical and electronic equipment used onboard a naval surface vessel. Guidance note: —

Vessel’s system means all systems other than weapon systems. Weapon systems per se are not included; however, they should not affect the vessel’s systems from functioning as intended.

—

Most naval vessels operate powerful transmitters concurrently with high sensitive receivers, often in close proximity to one another. This requires careful consideration in order to achieve a workable solution as equipment may be susceptible to radiated as well as conducted electromagnetic interference, hence all electrical and electronic devices should be considered a possible electromagnetic interference (EMI) source or victim. As mechanical structures may transfer electromagnetic interference, the vessel EMC considerations should also include relevant mechanical structures.

—

Aspects that relate to electromagnetic silencing e.g. the vessel’s magnetic signature and underwater electric potentials are beyond the scope of these rules. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.1.2 Vessels made of materials other than steel or aluminium, e.g. glass fibre reinforced plastics, shall be specially considered with respect to the shielding effectiveness of decks and bulkheads as well as the grounding system.

1.2 Principles 1.2.1 The design of the vessel shall ensure that all vessel systems, including safety systems, navigation systems, communication systems, propulsion systems and power systems can be operated concurrently, and at specified performance together with the vessel’s weapons, sensor systems and combat management systems. Guidance note: In instances that this requirement cannot be met, e.g. during simultaneous operation of vessel system and combat system, operational restrictions may be approved in each case. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.2 The design for EMC is a process that comprises planning, analysing, testing and verification. The design shall be documented by an EMC management document containing relevant technical EMC information. This includes at least limit values, technical solutions, drawings, guidelines to workforce, analyses and test results. Guidance note: A method is outlined in IEC 60533. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

1.2.3 The efforts required depend on type of equipment and on consequence of interference. The margin between the emissions and susceptibility shall be sufficiently high. If the consequence of disturbance is regarded as critical e.g. loss of life, this margin shall be at least 20 dB for onboard installations, or the probability of interference shall be acceptably low.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 106

Part 5 Chapter 13 Section 14

SECTION 14 ELECTROMAGNETIC COMPATIBILITY (EMC)

2.1 Terms 2.1.1 Bonding. Electrical bonding is a means of obtaining the necessary electrical conductivity between the unit and structure, which otherwise would not have sufficient electrical contact. Resistance ≤ 25 mΩ. measured at 1 kHz. Guidance note: Bonding and grounding has different meanings in that bonding connections are able to carry HF currents up to several hundred MHz, which is not the case for ground connections, normally made to carry currents in the range 0 to 400 Hz. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.2 Electromagnetic compatibility (EMC). The ability of electrical and electronic equipment, subsystem and system, to share the electromagnetic spectrum and perform their desired functions without unacceptable degradation from or to the specified electromagnetic environment. 2.1.3 Electrostatic discharge or protected area (ESD/EPA). The basic phenomenon is the build-up of static charge e.g. on a person’s body or equipment with subsequent discharge to the product when the person or equipment touches the product. ESD Protected Areas according to EN-100015-1. 2.1.4 Grounding. Equipotential point or plane which serves as a reference potential for a circuit or system. If ground is connected to the hull through a low impedance path, it can then be called an earth ground (i.e. earthing). Safety grounds shall always be at earth potential, whereas signal grounds are usually but not necessarily at earth potential. Guidance note: By hull is meant the hull itself inclusive the superstructure, main masts, bulkheads and decks if they are all jointed together by a low impedance path. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

2.1.5 Harmonic distortion. The phenomenon when non-linear loads, e.g. static power converters, arc discharge devices, change the sinusoidal nature of the A.C. power thereby resulting in the flow of harmonic currents in the A.C. system.

3 Documentation 3.1 Plans and particulars 3.1.1 The following plans and particulars shall be submitted for approval: — EMC Management Control Document (EMCD) describing management methodologies and documenting tasks. Guidance note: 1)

The document should as a minimum contain the following information: —

a description of the applied procedures to deal with the EMC work in the design and construction phases

—

overall vessel EMC requirements and standards (EMC zones with levels and installation procedures for each zone) including ESD and lightning protection

—

installation procedures for shielding integrity between zones

—

power distribution requirements and standards

—

equipment EMC requirements including standards with testing pass or fail criteria

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 107

Part 5 Chapter 13 Section 14

2 Definitions

2)

a system by system description including special EMC installation requirements and EMC data for all systems

Note that additional national military requirements may apply. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4 Design principles 4.1 General 4.1.1 The design shall be based on EMC management control procedures. These procedures shall in a systematic manner address the possible interference in and between the systems, to investigate them qualitatively and quantitatively and to form the basis for working out the remedial measures for EMC. 4.1.2 The equipment and installations shall be designed according to a recognised national or international standard. Guidance note: An example is STANAG 4435, which provides complete measurement methods and acceptance criteria for components. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4.1.3 It is recommended to divide the vessel and network into EMC zones and to specify limit values within each zone. 4.1.4 Various techniques can be utilised to achieve electromagnetic compatibility, e.g. selection of appropriate components with respect to emissions and susceptibility, physical separation, bonding, grounding, filtering and shielding. In instances abatement measures are required, these shall be selected in the order indicated below until the EMI problem has been resolved: — reduction of the noise to a minimum by application of simple means i.e. by physical separation, proper bonding or grounding and adequate cable terminations — separation of power and instrument cables — cables serving different systems shall have separate routing, and the distance shall be as large as practicable — isolation of EMI generating and EMI susceptible equipment i.e. by shielding and filtering.

4.2 Lightning protection 4.2.1 In order to reduce the possibility of occurrence of dangerous sparking, down-conductors shall be arranged. The following parts of structure may be considered as natural air-termination components: — the vessel’s metal hull — metal components such as pipes and tanks that have a thickness of material not less than 2.5 mm.

4.3 Electrostatic discharge 4.3.1 An anti-static environment shall be provided by selecting materials with ESD properties which do not allow charging of personnel for items which may be exposed to friction, e.g. deck-coverings, railings, benches, seats and chairs.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 108

Part 5 Chapter 13 Section 14

—

5.1 General 5.1.1 Sensitive equipment shall be installed with sufficient distance from sources of interference, e.g. power cables and transmitting antennas. Guidance note: —

The choices of signal types are critical with regards to corruption of the signal information due to susceptibility to EMI, in particular for top deck signals near transmitting antennas. Signal types for process signals should preferably be 4 to 20 mA, and signal types for communication should be balanced.

—

Examples of safe distances are outlined in IEC 60533.

—

For communication it is recommended to use fibre optical links. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2 Shielding 5.2.1 Proper installation techniques shall be utilised in order to ensure shielding integrity. All decks and bulkheads acting as shields shall be joined continuously. Guidance note: Spot welding, riveting, detachable fixings without EMI gaskets will usually not provide acceptable shielding effectiveness. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.2 Framing of shielded windows, doors, hatches shall either be welded or soldered circumferentially to the shield. Alternatively, flanges and EMI gaskets can be used if not prone to corrosion. 5.2.3 Shielded doors and hatches shall be fitted with conductive EMI-gaskets to ensure circumferential connection of the door blade or hatch to the frame when the door or hatch is closed. 5.2.4 Pipeline penetrations shall have circumferential contact with the shield. 5.2.5 Ducts and pipes penetrating a shield shall be designed to avoid degradation of the shielding effectiveness. Most important are the largest penetrations and the connection to the shield. The principle of a wave-guide beyond cut-off frequency can be utilised. If openings need to be larger than this principle allows, then e.g. honeycomb inserts shall be applied. Documentation shall show that required attenuation of the ducts meets the shielding requirements. 5.2.6 Fibre optic cables consisting of non conducting parts that need to penetrate a shield shall be arranged through a metal pipe, see also [5.2.5]. 5.2.7 All cable screens shall be terminated circumferentially when entering or leaving equipment or shielded rooms or zones.

5.3 Bonding and grounding 5.3.1 The ground system shall be the reference potential for all installations onboard the vessel. The hull, superstructure, masts, bulkheads and decks will all be part of the grounding system. It is necessary that these parts of the vessel be designed to exclude potential differences.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 109

Part 5 Chapter 13 Section 14

5 Installation

Guidance note: —

HF bonding should be addressed in the EMCD.

—

See MIL-STD 1310G. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.3.3 For cables provided with an outer screen, the screen shall normally be terminated to ground at least at both ends, and when entering or leaving shielded zones. Guidance note: Circumferential termination is necessary to ensure a low impedance path to ground. Pigtails are generally not allowed. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.3.4 For multi-screened, double screened or individually pair-screened cables, the outer screen shall be terminated to ground at both ends, and at any EMC-zone penetration. The other screens shall normally be terminated to ground at the most sensitive end only. Alternatively the other screens should be terminated to ground in accordance with provisions of the manufacturer. 5.3.5 For distributed system the zero potential reference may be grounded, but only at one single point, preferably at the main unit. The zero potential reference shall then be floated in sub-units. If necessary the zero potential reference may be floating versus the hull of the vessel.

5.4 Cabling 5.4.1 Cables that are prone to radiating EMI, shall be screened. At least one screen shall be provided, but multiple screens or other special cables suggested by the equipment manufacturer can be used. 5.4.2 Cables from receiving and transmitting antennas shall normally be arranged in solid metal pipes between the antenna and transceiver. However, alternative arrangements may be considered, e.g. physical separation or solid screen, if same or better performance can be achieved. 5.4.3 Cable trays shall be routed as close as possible to bulkheads or decks or any ground plane to minimise the pickup loop of the cable screen. 5.4.4 Cables shall be categorised according to energy level and frequency of signal. Cables carrying signals of same category can be installed next to each other. Cables with signals of different category shall be separated. Guidance note: See Class Guideline No. 45.1 for distances of adequate segregation. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.4.5 Cables to the top deck equipment shall generally be routed entirely below decks or installed in metal piping. 5.4.6 Cables for equipment outside shielded zones shall avoid routing through shielded zones. 5.4.7 All unused conductors in a cable shall normally be bonded or grounded at the most sensitive end only. However, grounding or bonding at both ends may be accepted if this provide a more safe solution.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 110

Part 5 Chapter 13 Section 14

5.3.2 Installation of electrical and electronic equipment shall be properly high frequency (HF) bonded to the ground system.

5.5.1 If and when EMI-filters are applied, these shall be installed according to the manufacturer's specification. Guidance note: See STANAG 1008 and STANAG 4435 for additional information. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.5.2 Equipment connected to network furnished with EMI- filters, shall be marked with the following warning sign: THIS EQUIPMENT IS CONNECTED WITH AN EMI-FILTER. SPECIAL ATTENTION TO BE PAID TO EARTHING. REFER TO THE MANUFACTURER’S INSTRUCTIONS.

5.6 Lightning protection 5.6.1 Equipotential bonding shall be applied to internal lightning protection systems by means of bonding conductors or surge suppressers connecting metal framework of structure to conductive parts of the electrical and telecommunication installations within the space to be protected. Bonding Cu-conductors shall have a 2 minimum cross section of 16 mm . Guidance note: In instances Cu-conductors cannot be applied due to corrosion problems, other materials may be accepted provided the electrical features of the installations are similar or better. It may be required to analyse the impact of very high magnetic fields caused by the lightning current. This is particularly important if the hull made of aluminium or GRP. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.7 Electrostatic discharge 5.7.1 Selected areas such as rooms with sensitive electronics, i.e. the bridge, operational rooms, radio rooms, engine control rooms, electronic workshops, ordnance facilities and storage rooms for explosives shall be fitted with deck coverings providing discharge of electrostatic charged personnel. Guidance note: —

Wrist straps for discharge of electrostatic charged personnel should be fitted on electronic cabinets intended for regular inspection, field service or repair.

—

Electrostatic sensitive devices (spare parts) should be wrapped in metal-in/metal-out static shielding bags according to package material described in EN 100015-1 or a similar standards. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.8 Marking 5.8.1 Shielded zones shall be clearly marked. Signboards shall be posted at access points and at cable penetrations into other shielded zones. 5.8.2 Rooms containing electrostatic sensitive devices shall have signs for ESD protected area according to a recognised standard e.g. EN-100015-1.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 111

Part 5 Chapter 13 Section 14

5.5 Filtering

6.1 General 6.1.1 The tests shall demonstrate that the systems or equipment or circuits or functions are unaffected by relevant levels of electromagnetic emissions, and that they are unaffected by each other when each system is operated as a source. Guidance note: Testing may be waived if the EMC properties of systems or equipment or circuits or functions have been satisfactory documented e.g. previously type tested. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

6.1.2 Measurements shall show that no leakage current exceeds 30 mA in any network or load configuration, and that the leakage current currents per circuit of equipment is less than 30 mA. 6.1.3 Measurements shall be carried out to show that the E-field shielding effectiveness between the various zones is as required, as well document the electromagnetic environment within each zone. 6.1.4 Measurement shall show that for distributed systems, the zero-potential reference is terminated to ground, at one single point only, if it is not floated completely.

6.2 Factory acceptance tests (FAT) for equipment 6.2.1 Immunity and emission tests may be required in order to verify that the limit values are not exceeded and that the equipment has been designed according to the plans and specifications.

6.3 Harbour acceptance tests (HAT) for the vessel 6.3.1 Immunity and emission tests shall be performed on systems on board in order to verify that the limit values are not exceeded and that the equipment has been delivered and installed according to the plans and specifications.

6.4 Sea acceptance tests (SAT) for the vessel 6.4.1 Systems or functions that for practical reasons could not be verified by HAT shall be subjected to SAT.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 112

Part 5 Chapter 13 Section 14

6 Testing

1 General 1.1 Application 1.1.1 The rules in this section apply to vessels with class notation Naval or Naval support(SAM), covering storage rooms for explosives on naval surface vessels.

1.2 Definitions 1.2.1 Storage room for explosives is an enclosed room designated for storage of major ammunition, explosives, torpedoes and missiles. 1.2.2 Hazardous areas are all areas in which explosives are stored or transported as a part of normal operational routines. 1.2.3 Explosives are all types of ammunition and weapon systems equipped with explosive material. 1.2.4 Wave-guide is a device designed to propagate radio waves between radar transceiver and antenna.

2 Basic requirements 2.1 General 2.1.1 A safety arrangement plan shall show the location of hazardous areas. 2.1.2 Explosive storage space on deck and loading areas shall be shown on a safety arrangement plan identifying operational restrictions in the area and adjacent areas.

2.2 Plans and particulars to be submitted 2.2.1 A safety arrangement plan for storage and transportation of explosives showing the general layout and all openings or doors shall be submitted for approval. 2.2.2 Plans and particulars for storage rooms for explosives covering electrical installations and fire safety, shall be included in the general documentation to be submitted for these areas.

3 Arrangements 3.1 General 3.1.1 Access to storage rooms for explosives shall be via areas of low fire risk and secure efficient passage. 3.1.2 Access doors to storage rooms for explosives shall be equipped with a secure locking mechanism and an inspection test plug. Normal access doors and hatches shall be fitted with means for locking devices outside the storage room. Emergency escape hatches shall be fitted with means for locking devices inside the storage room.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 113

Part 5 Chapter 13 Section 15

SECTION 15 STORAGE ROOMS FOR EXPLOSIVES

3.1.4 If storage rooms for explosives are situated in areas with vibrations adverse to proper storage of intended explosives, suitable measures shall be taken. 3.1.5 Arrangements shall be made such that the temperature and humidity of the air in the storage rooms for explosives can be regulated within acceptable limits for the type of ammunition to be stored. Guidance note: The temperature and relative humidity should generally not exceed 25°C and 50 to 70% respectively. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.6 Storage rooms for explosives shall be fitted with arrangements for detecting temperatures in the space. 3.1.7 The location of the inlets to the ventilation system for the space shall provide sufficient protection against warm air or hazardous vapours being emitted from galleys and pump-rooms tanks. 3.1.8 Wave-guides, ventilation ducts, cables and other utility systems shall normally not be routed through storage rooms for explosives. Guidance note: If it is absolutely necessary to route such components inside storage rooms for explosives, they should be routed inside structural ducts. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

3.1.9 Securing arrangement for explosives shall be provided. 3.1.10 Storage rooms located below the vessel waterline shall be provided with an air and overflow arrangement of sufficient capacity in order to prevent excessive pressure build up during total water flooding. 3.1.11 Storage rooms for explosives located below the waterline shall be arranged for drainage with suitable draining facilities (see Sec.6 [7.4]). 3.1.12 Storage rooms for explosives located above the waterline shall be arranged with drainpipes leading overboard. The drainpipes shall have a capacity of at least 125% the capacity of the water spray system. Overboard valves shall be provided with remote operation from on or above the damage control deck (Sec.6 [7.5]). Guidance note: For valves where the inboard end of the drainpipe is submerged at the final waterline after damage as defined in Sec.5, arrangements shall be provided for drainage with submersible drain pumps. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

4 Structure 4.1 Structural requirements 4.1.1 Decks of storage rooms for explosives shall be dimensioned as for cargo rooms, see HSLC Pt.3 Ch.1 in the rules for classification of HS, LC and NSC, or for a water head to the deck above, whichever is the greater. 4.1.2 The local structures shall be checked for heavy items placed in the storage rooms for explosives.

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 114

Part 5 Chapter 13 Section 15

3.1.3 Supply lines to the storage rooms for explosives shall be arranged for secure handling of the ammunition.

5.1 General 5.1.1 Hydraulic equipment to be used in storage rooms for explosives should use fire safe hydraulic fluids. Guidance note: Air powered equipment shall be preferred in storage rooms for explosives. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2 Structural fire protection 5.2.1 The storage room for explosives shall be of a permanent watertight construction and surrounded by permanent A-60 or equivalent class divisions. Guidance note: The storage room should in general be protected from external fires. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.2 For light, high speed craft designs based on fibre composite material and sandwich constructions the storage rooms for explosives shall be of a permanent watertight construction and surrounded by permanent A-30 or equivalent class divisions. 5.2.3 Storage rooms for explosives that are an integral part of the vessel shall not be adjacent to machinery spaces of category A, galleys, battery rooms, major electrical power distribution or other spaces in fire risk category (6), (7) and (9) as defined in Sec.10 [6]. If this is not practicable, a cofferdam of at least 0.6 m shall be provided separating the two spaces. One of the bulkheads in the cofferdam shall be of A-60 or equivalent construction. Guidance note: If this is not practicable, a risk analysis may be carried out to demonstrate that an alternative solution maintains the safety objectives. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.2.4 Access doors to storage rooms for explosives shall be fire resistant to A-60 class or equivalent, watertight and capable of sustaining an external explosion pressure of not less than 1 bar. 5.2.5 Spaces built as an integral part of the vessel and used as an area for missile launchers shall be protected by A-60 or equivalent class divisions.

5.3 System fire safety 5.3.1 The storage rooms for explosives and adjacent rooms shall be equipped with fire detectors. 5.3.2 Electrical equipment and wiring shall not be fitted in areas where explosives are stored, unless it is essential for the safety and operation of the ship. Only certified-safe equipment of temperature class T5 having a degree of protection IP6X shall be installed. Guidance note: Equipment other than of a certified-safe type may be used if documented to have a maximum surface temperature of 100°C. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 115

Part 5 Chapter 13 Section 15

5 Fire safety

5.4.1 A water sprinkler system shall be installed in the space. The water spray system shall have an 2 application rate of at least 32 l/m per minute. Equivalent means may be accepted. Guidance note: The feeding pipe of the sprinkling system should be provided with a ball float stop-valve, or similar safety device, just after the entrance to the storage room unless drainage is arranged for. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.4.2 On activating the sprinkler system the electrical installation, if any, should be disconnected. The circuit breaker shall be located in the same place as the spray activator together with a signboard showing the correct procedure. 5.4.3 For storage rooms for explosives located below the vessel’s water line, a water total flooding system shall be installed if relevant for the type of explosives to be stored in the room. 5.4.4 The sprinkler alarm system shall be connected to the main alarm system. 5.4.5 The fire extinction system for storage rooms for explosives shall be equipped for manual and or automatic operation. Guidance note: The requirement for automatic operation depends on the type of explosive to be stored, and will be agreed upon from a case to case basis. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

5.4.6 Valves in fire extinguishing systems for storage rooms for explosives shall be fitted with locking devices to prevent unauthorised use. 5.4.7 Storage rooms for explosives shall be arranged so as to include a back-up to the main fire water supply.

6 Radiation hazards 6.1 Electromagnetic radiation protection 6.1.1 Storage rooms and transport routes for explosives shall be protected from electromagnetic radiation unless the explosive store in itself is adequately protected from radiation. Guidance note: Requirements regarding aspects related to radiation hazards may be found in Sec.13. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e---

7 Signboards 7.1 General 7.1.1 Storage rooms for explosives and areas identified for ammunition storage shall be marked with signboards displaying: — no smoking — warning against use of electronic radiating equipment

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Page 116

Part 5 Chapter 13 Section 15

5.4 Fire protection

Rules for classification: Ships — DNVGL-RU-SHIP-Pt5Ch13. Edition October 2015, amended January 2016 Naval and naval support vessels

DNV GL AS

Part 5 Chapter 13 Section 15

— warning against use of inflammable liquid — warning against activity which could compromise the safety of the ammunition — observe anti static precautions.

Page 117

DNV GL Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification and technical assurance along with software and independent expert advisory services to the maritime, oil and gas, and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our 16 000 professionals are dedicated to helping our customers make the world safer, smarter and greener.

SAFER, SMARTER, GREENER