Scaffolds

  • Uploaded by: girishkris
  • 0
  • 0
  • November 2019
  • PDF

This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA


Overview

Download & View Scaffolds as PDF for free.

More details

  • Words: 1,561
  • Pages: 24
WORKING AT HEIGHTS

SCAFFOLDS

SCAFFOLDS

All scaffolds must be designed, erected, inspected, maintained by suitable competent persons.

A safety harness and lifeline secured to a suitable anchorage point must be used when working on a tower or mobile access platform.

SCAFFOLDS Check that all scaffolds: •

Are planned, installed, altered and dismantled by a competent person and that the work is supervised.



Are capable of supporting the imposed loading.



Have boards which are wide enough to carry out the work and are properly fitted.



Have safety ladder or other means of access to the platform.



Are appropriate to the task before using them.

SCAFFOLDS

FOUNDATIONS: •

All free standing structures must be built on solid foundations and must be vertical.



If on sloping ground, they must be prevented from slipping



Towers inside buildings must be on level floors or adequately compacted sub-bases.



When the ground is soft foundations, a sole base must be mounted and the tower must be firmly fixed.



When the ground is sloping, the sole plates must be dug in flat.

SCAFFOLDS

Bracing: • The towers must be adequately stiffened on all sides and in plan at every alternate lift. Access: • there must be a safe method of getting to and from the work platform. • It is not safe to climb up the end frames of the tower, except where the frame has an appropriately designed built-in ladder. • Access to the top of towers must be by ladders either built into the framework or attached to the top of the tower and preferably inside the base area.

SCAFFOLDS

Deck: • • •



The working surface must be fully boarded. The supports for the boards must be fit for the purpose. If the boards are short, they must be prevented from sliding. The deck must be provided with guard rails and toe boards

Operation: •

The user must apply no horizontal force at any of the working decks either by hauling heavy ropes and cables or lifting significant loads.

SCAFFOLDS STABILITY •

Make sure the tower is on firm level ground with the wheels or feet properly supported.



Do not use bricks or building blocks to take the weight of any part of the tower.

NG O WR T

H RIG

SCAFFOLDS STABILITY



The taller the tower, the greater its instability.



As a simplified rule, if the tower is to be used in exposed conditions, the height of the working platform must be no more the minimum base dimension.



If the tower is to be used inside, on firm, level ground, the ratio may be extended to 3.5.



Mobile access towers must be fitted with lockable castors in good conditions at the bottom of the uprights.

SCAFFOLDS STABILITY

The stability of any tower may be affected by: •

Exposure to strong winds



Loading of heavy equipment



Hoist of heavy materials



Use of tower for heavy or complex operations



Climbing from outside Use a support for ladders: never place a ladder on the top platform •

in order to extend the height of a tower scaffold. •

NG O WR

SCAFFOLDS EDGE PROTECTION

Suitable edge protection (toe boards and guard rails) should be provided on all platforms. Guard rails must be, at least, 910mm high and toe boards at least 150mm high. An intermediate guard rail (or suitable alternative) must be provided so the unprotected gap does not exceed 470mm.

SCAFFOLDS INSPECTION •

Scaffolds must be inspected at a maximum of 7 working day intervals, always before use and after inclement weather or movement.



When dismantling a tower do not throw rope, if necessary.

SCAFFOLDS ERECTION AND DISMANTLING



Helmets must be worn at all times during the erection or dismantling of towers and when the tower is in use.



When dismantling a tower, do not throw materials down; lower them down by rope, if necessary.

DUTIES

SCAFFOLDS

As guidance, reference can be made to Table 1. Taken from British Standard BS 5793 : 1993 Tubular steel scaffolds TABLE 1. ACCESS AND WORKING SCAFFOLDS OF STEELTUBE Distributed loads on platform KN/m2

Max. N.º of platform

Commonly used widths (using 225mm boards)

Max. Bay length

1 working platform

3 boards

2,7m

4 boards

2,4m

5 boards or 4 boards + 1 board inside

2,1m

Duty

Use of platform

Inspection and very light duty

Inspection, pointing, stone cleaning, light cleaning and access

0,75

Light Duty

Plastering, painting stone cleanings glazing

1,50

2 working platforms

General purpose

General building work including brickwork, window and mullion fixing

2,00

2 working platform +1 at very light duty

SCAFFOLDS DUTIES As guidance, reference can be made to Table 1. Taken from British Standard BS 5793 : 1993 Tubular steel scaffolds

TABLE 1. ACCESS AND WORKING SCAFFOLDS OF TUBES AND COUPLERS

Duty

Heavy duty

Masonry or special duty

Use of platform

Distributed loads on platform KN/m2

Block work, brickwork, heavy cladding

2,50

Masonry work, concrete block work and very heavy cladding

3,00

Max. N.º of platform

Commonly used widths (using 225mm boards)

Max. Bay length

2 working platform + 1 at very light duty

5 boards or 5 boards + 1 inside or 4 boards + 1 inside

2,0m

6 to 8 boards

1,80m

1 working platform + 1 at very light duty

SCAFFOLDS

Ladder access to scaffolds •

Ladder access to scaffolds are usually built and supported by the stiles.



Every sloping ladder must stand on a firm and level base.



Ladders must not be extended by lashing two length together.

SCAFFOLDS

Ladder access to scaffolds •

Ladders access to scaffolds must be provided with toe boards and guard rails.



If it is not possible to have toe boards adjacent to the rungs, use double guard rail.



Where practicable, it should be set at an angle of 4 vertical to 1 horizontal

H

D=

H/4

TYPES OF SCAFFOLDS PUTLOG SCAFFOLDS • They consist of a single row of uprights, parallel to the face of the building. • The inner edge of the platform is as close to the wall as practicable. • The scaffold uses the wall the building to support the inside edges.

Bay le

Longitudinal bracing in zig-zag patern

ngth

Guardrails and toeboards fixed to the standards

Through tie Bridle

Joint pin

Putlog or right angle coupler Putlog adaptor or head Flat ended putlog

Joint pin or sleeve coupler

TYPICAL PUTLOG SCAFFOLD

Ledger fixed with right angle couplers

Longitudinal or focade bracing

38x225 mm timber sole plate when standing on soil

TYPES OF SCAFFOLDS PUTLOG SCAFFOLDS • The scaffold is fixed to the wall by a tie member, normally a tube or an anchorage. • Suppliers’ information about tie methods must be followed.

Secured packing

• Where no specific information is supplied, the requirements of the relevant national standards must be followed. • The type of tie must be selected to suit the typing requirements and the nature of facade.

Bridle tube

• Building structure integrity must be established by test, if necessary. Tie

• The structure must be adequate to sustain the loads which will be transferred to it.

TYPES OF SCAFFOLDS INDEPENDENT SCAFFOLDS • An independent scaffold consists of a double row of uprights, with each row parallel to the building. • The inner row is set as close to the building as practicable. • The transoms are not built into the wale of the building. • The scaffold must be tied to the building. • Longitudinal (diagonal) bracing is generally fixed to alternate pairs standards. TYPICAL INDEPENDENT SCAFFOLDS

TYPES OF SCAFFOLDS TOWER AND MOBILE ACCESS SCAFFOLDS

TOWER

MOBILE TOWER

TYPES OF SCAFFOLDS TOWER AND MOBILE ACCESS SCAFFOLDS BEFORE USING ANY SCAFFOLD, CHECK:

• You have the correct quantities of all the components for the proposed height of the tower, including a rope, if necessary, to assist erection/dismantling • Precautions against collision of persons or vehicles were taken. •

In mobile access scaffolds, castors are locked as well as fitted

TYPES OF SCAFFOLDS TOWER AND MOBILE ACCESS SCAFFOLDS When assembling the scaffold: • Fit all components in the exact sequence shown in the manufacturer’s manual. • Fit stabilisers as soon as possible when erecting the scaffold. • Check that the tower is vertical, in both planes. • Fit two guard rails on each side of the platforms and toe boards to all platforms, except where the manufacturer’s manual indicates otherwise.

X Wrong

Right Remember all manufacturer’s instructions are given taking into account that the tower has all precaution to ensure that it is stable.

TYPES OF SCAFFOLDS TOWER AND MOBILE ACCESS SCAFFOLDS • In order to move the tower, follow these steps: - Check that materials and people are removed - Unlock the tower castors.

X Wrong

- Ensure that the ground level path is firm and level without obstructions, bumps, hollows, power cables, phone wires…etc

 Right

- Move the tower by manual effort from ground level only. - Re- lock the tower castors and replace stabilisers of the equipment.

X Wrong

TYPES OF SCAFFOLDS TOWER AND MOBILE ACCESS SCAFFOLDS BEFORE USING ANY SCAFFOLD, CHECK: • That the manufacture’s instruction manual is available. • All components for damage or corrosion. • That equipment is in compliance with local bye-laws and all regulations. • That the ground is firm and level.

X Wrong

 Right

Related Documents


More Documents from "Karthikeyan G"

Scaffolds
November 2019 13