Offshore Safety Performance Management.doc

Pillai Sreejith

Management of Offshore Safety Performance 1. Introduction: Major accidents that occurred world over, be it ‘Piper Alpha’, ‘BP Texas’ or ‘Mumbai High’ have given the oil & gas operators enough lessons to make it one of the safest industries in the world. Safety Case regime and the concept of Formal Safety Assessment (FSA) initiated after the 1988 Piper Alpha accident as recommended by Lord Cullen has significantly contributed to the improved safety performance of offshore industry. 20 years later, the ongoing ‘Step Change in Safety’ campaign in UK is all geared up to make UK oil & gas industry as the safest industry to work in by 2010. In the ageing UKCS (UK Continental Shelf) offshore installations, predominantly the North Sea platforms asset integrity management is a key concern. The KP (Key Programme) 3 Asset Integrity Programme [8] by UK HSE has revealed several interesting facts on the SCE (Safety Critical Elements) performance and some of the typical hazardous conditions that exist in these offshore installations. This highlights the fact that the offshore industry is yet to fully learn from the major accidents and there is room for safety improvements or rather a shift of focus from HSE to Asset Integrity Management (AIM). This paper is aimed at having a realistic assessment of safety performance of present offshore oil & gas industry in line with various efforts that are on such as UK HSE KP initiatives, Publications such as HSG 254 [2] and UK Safety Case regulations, 2005 [1]. It is also hoped that this note will trigger some discussions to optimize the Major Hazard Management (MHM) programme by the offshore operators.

2. SCE Performance and Brown Field Safety Case: Piper Alpha disaster that killed 167 provided plenty of valuable lessons that can make the offshore industry as one of the safest industries in the world. Although several of the Piper learning is being assessed as part of FSA studies before commissioning and the safety case is updated every 5 years or based on various defined update triggers, the real safety barrier or SCE performance is yet to be properly understood by the operators in its right perspective. The UK HSE KP 3 inspection results clearly indicate this fact. The author also had a chance to assess the safety barrier or SCE performance in a few Management of Offshore Safety Performance Management (MOSP)

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Pillai Sreejith

ageing offshore installations in South East Asia and found that the focus is still on HSE and AIM is yet to receive the attention it deserves. The risk levels on offshore installations logically depend on the SCE or safety barrier performance for operating installations. Updating of brown field installation safety case say, based on a major modification should logically start with the SCE performance verification. The traffic light system used by UK HSE KP inspections is a simple and practical way to assess the performance of SCEs. These assessment results could be used to determine the new MAH (Major Accident Hazard) probabilities thereby arriving at realistic risk levels.

3. Performance based QRA: The traffic light system used by NOPSA & UP HSE [3] [8] can be represented graphically as shown below for the better understanding of readers:

Taking cues from the KP 3 inspection report and NOPSA guidelines [3] the following guidelines could be used in order to calculate the ‘realistic’ risk levels in the brown field QRA. Traffic Light

Interpretation

Risk Calculation Guidelines

Green

Complies with performance standard

The SCEs are in good condition. The probability of failure or the frequency used are based on historical data quoted from reliable failure data sources reliable sources [CMPT [3], OREDA [4], PARLOC [5], UK HSE [4]etc;

Amber

Partially complies (incomplete system, failures)

The SCEs are degraded. The probability of failure or the frequency is 1.5 times higher than the values used for green light.

Red

Non compliant (major failures or key elements missing)

The SCEs are completely degraded. The probability of failure or the frequency is double the values used for green light.

Management of Offshore Safety Performance Management (MOSP)

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Pillai Sreejith

The changed (mostly increased) risk levels from the base case risk level could be used to highlight the point that unless the SCEs or barriers performance is ensured, the risks can go beyond the tolerable ALARP region. The author has successfully used this point to communicate the message to the offshore personnel that ‘unless safety systems are maintained, MAH can happen and the risk levels may not be in the ALARP region anymore’. The various risk levels can be represented on an ALARP triangle as shown below in the brown field QRA report. This diagram clearly shows that the individual risk after assessing the SCE Performance is more than the base case risk highlighting the need to strengthen the AIM process.

4. Safety Systems / Barriers / Safety Critical Elements: The author feels that if the Bow Tie Assessment (BTA) technique [10] can be better utilized in all the FSA studies that are required as part of Offshore Safety Case to clearly demonstrate that all major hazards are assessed and managed to ALARP level. Logically, for a brown field installation, if all SCEs or barriers are performing satisfactorily (Green traffic light), then the risks of the installation can be considered to be in the ALARP tolerable region.

If bow ties are constructed for each of the MAEs (Major Accident Events) or MAH (Major Accident Hazards) based on the HAZID (Hazard Identification), these bow ties can be modified for each of the FSA (Formal Safety Assessment) studies to demonstrate that the assessments are in compliance in UK SCR (Safety Case Regulations), 2005. This Management of Offshore Safety Performance Management (MOSP)

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Pillai Sreejith

assessment process will ensure that all barriers are assessed in all the safety assessments and this also becomes a clear demonstration that all barriers or safety systems or SCEs are designed to prevent or control MAE/ MAHs. The possible applications of bow ties in the safety case are included in the table below: FSA Study

Bow Tie Application

HAZID

Once the MAEs are identified, develop bow ties with all safety systems /barriers and the recommended barriers for each of the MAE.

ESSA

The mitigation safety systems on the right side of bow tie (emergency

(Emergency System Survivability

systems) will have to be assessed for survivability during their designed

Assessment)

performance objectives [9].

ETRERA

The recovery measures will also be on the right side of bow tie. Specific

(Escape,

Temporary

Refuge,

Evacuation and Rescue Analysis)

bow ties may be developed for escape, evacuation, refuge and rescue emergency situations to demonstrate that all SOLAS (Safety of Life At Sea) required are in place based on potential impairment conditions.

FEA

Specific bow ties for fire, explosion, and gas release may be developed to

(Fire and Explosion Assessment)

demonstrate that all these MAEs are controlled and mitigated using adequate

NHHA

Specific bow ties for dropped objects, ship collision and transportation risks

barriers based on potential impairment conditions.

(Non-Hydrocarbon

Hazard

may be developed to demonstrate that all these MAEs are controlled and

Assessment)

mitigated using adequate barriers based on potential impairment conditions.

QRA

The impairment frequencies of MAEs can be calculated with inputs from

(Quantitative Risk Assessment)

FEA & NHHA studies by using Fault Trees (FTA) on the left side of bow and Event Tree (ET) on the right side of the bow. One bow tie per each of the MAE could be developed as part of QRA to demonstrate that all threats and barriers are considered while calculating impairment frequencies.

ALARP Demonstration

For a brown field QRA, the risk levels should be calculated based on actual SCE/safety barrier performance. Traffic light system could be used to represent performance of safety barriers in the bow tie diagram. If all the barriers are performing as designed / desired (Green), then the installation is regarded as ‘Safe to Operate’ and ALARP.

Verification Scheme

The Written Scheme of Examination (WSE) as part of SCE (Safety Critical Element) verification could be demonstrated by developing bow ties with specific inputs from Performance Standards (PS).

HSE Safety Case

In the FSA summary section, the bow ties developed in all assessments could be included. Finally, based on safety assessments, consolidated bow ties could be developed for all MAEs in line with potential impairment of defined sensitive receivers.

Management of Offshore Safety Performance Management (MOSP)

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Pillai Sreejith

5. HSG 254, Swiss Cheese Model & Dual Performance Assurance: HSG 254 [2] clearly provides detailed steps to establish dual safety performance indicators by utilizing Swiss Cheese model. If the MAH Bow Ties or Swiss Cheese diagram can be used as reference to define the dual safety performance indicators, then the logical link can be established from MAH to barriers or SCEs to the safety performance. For example, if we take the Swiss Cheese barrier diagram (shown below) for the MAE/ MAH Hydrocarbon Fires & Explosions, the dual process safety indicators are derived from the specific barriers or SCEs. These performance indicators could then be monitored through the HSE Management system to measure process safety performance as part of MHM process.

6. Focus on the left side of Bow: While developing performance safety indicators, emphasis should be on the control / prevention barriers than the recovery and mitigation measures. In other words, focus more on the left side of the bow (or the cheese stacks near the threat) while developing safety performance indicators so that the efforts will be concentrated on preventing MAEs than to mitigate and recover which is the logical approach. All major accident

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cases have clearly proved the fact that it is nearly impossible to mitigate and recover from major accidents.

Focus on the left side of the bow!

7. SCE Performance Assurance: Verification scheme is a Safety Case Regulation, 2005 [1] requirement and is a critical document that demonstrates the performance assurance of SCEs. The performance, assurance and re-assurance details in the SCE performance standards should be incorporated into the Centralized Maintenance Management System (CMMS) or AIM. Generally the Critical Function Tests (CFTs) are defined and prioritized for all SCEs in the CMMS.

8. Conclusion: The Offshore MHM Programme could be re-visited based on the inputs provided in this discussion paper. Develop a programme to ensure process safety performance: o

Develop specific bow ties for each of major accidents;

o

Ensure that there are more safety barriers on the preventive / control side of the bow;

o

Focus on the preventative / control barriers while developing and monitoring dual safety performance indicators;

o

The SCE performance assurance and re-assurance details defined in the performance standards should be included in the CMMS or AIM programme;

o

Monitor both the process safety and occupational safety performance using separate sets of performance indicators; remember BP Texas case!

o

For brown field QRAs, calculate the risk levels based on SCE performance; and

Management of Offshore Safety Performance Management (MOSP)

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Pillai Sreejith

o

Finally communicate the MHM programme to all concerned employees through a 1 day training programme using pictures, diagrams, and major accident case studies.

References: 1. UK Offshore installations Safety Case Regulations, 2005 2. UK HSE HSG 254 Developing Process Safety Indicators-A step by step guide for Chemical and major hazard industries 3. NOPSA guidelines on Facility Integrity - Topsides Maintenance System Offshore (http://www.nopsa.gov.au/programmes) 3. Centre For Marine and Petroleum Technology (CMPT), Guide to Quantative Risk assessment for Offshore Installations, Spouge J. (1999) 4. UK HSE Hydrocarbon Releases Database System, Version 1.1.3, April 2005 5. OREDA- Offshore Reliability Data, SINTEF 6. PARLOC (2001), Loss of Containment Data for Offshore Pipeline and Riser, HSE Offshore technology Report, OTH 93 424 7. DNV Technica, World Offshore Accident Databank, statistical Report 1992 8.

UK

HSE

KP

3

Asset

Integrity

Programme

Report

(http://www.hse.gov.uk/offshore/kp3.pdf) 9. Insights into ESSA, Pillai Sreejith (http://www.pdfcoke.com/doc/8402933/Insights-IntoESSA) 10.

Bow

ties

and

Offshore

Safety

Studies,

Pillai

Sreejith

(http://www.pdfcoke.com/doc/8438367/Bow-Ties-and-Offshore-Safety-Studies) Author: Pillai Sreejith [email protected]

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