Approaches to integrating human factors in Seveso II safety cases

1. Approaches to integrating human factors in Seveso II safety cases Rob Cotterill DNV Consulting

2. PRISM Seminar, Bratislava Slide 2 DNV�s worldwide network

3. PRISM Seminar, Bratislava Slide 3 Development and implementation of safety management systems Identification and assessment of the risks from major hazards Innovative safety cases Human factors of major accident prevention Behavioural safety/culture change Environmental performance improvement DNV and Safety Management

4. PRISM Seminar, Bratislava Slide 4 The risk management agenda

5. PRISM Seminar, Bratislava Slide 5 Top Ten HF Issues

6. PRISM Seminar, Bratislava Slide 6 Understanding human failure

7. PRISM Seminar, Bratislava Slide 7 HF approaches to risk assessment Method 1: HF in the Safety Case Top down approach All human operations Part of Seveso safety case Method 2: HF in major accident hazards Bottom up approach Concentrating on MAH scenarios Implemented into safety case

8. PRISM Seminar, Bratislava Slide 8 Method 1: HF in the Safety Case Part of overall COMAH assessment: Descriptive Elements Predictive elements MAPP & SMS Technical elements Emergency response Source information HF aspects in several elements Supporting appendix of HF information Referred to in all relevant sections

9. PRISM Seminar, Bratislava Slide 9 Human factors Appendix Description of the human factors assessment of the plant Aim: To demonstrate that human factors issues have been taken account in the risk assessment To show that their potential effect has been considered as a contributor to the overall risk levels arising from the day to day operation

10. PRISM Seminar, Bratislava Slide 10 Human factors Appendix Identification and consideration of specific human factors issues that have led to major incidents in the past. Application of task analysis and human error identification techniques for the assessment of safety critical operations and maintenance tasks. Identification of the potential for violations of procedures to increase risk levels on site. Organised according to key human factors issues : Identification of potential for human failures. Demonstration of control measures. Justification of the reliance on human reliability.

11. PRISM Seminar, Bratislava Slide 11 Data collection Review of MAH tables. Site tour including discussion of activities in the following areas: Fuel receipts. Tank farms. Interceptors. Tanker loading bays. Interviews with: Terminal manager. Operations staff. Maintenance manager. Security staff. Demonstration of operations in the control room. Review of site held documentation including: Safety management system. Key risk control systems. Site HAZOP.

12. PRISM Seminar, Bratislava Slide 12 Error Analysis: Sherpa technique

13. PRISM Seminar, Bratislava Slide 13 High potential human error operations Road tanker loading Recovery from a compartment overfill (contained). Recovery from an overfill resulting in product spillage. Fuel receipts Filling COC tank. Operations tasks in and around the tank farm. Pump inspection. Inspection of loading bays. Testing of Fire pumps.

14. PRISM Seminar, Bratislava Slide 14 Demonstration of existing control measures Risk ranking of human errors Linking human errors to MAH scenarios Identifying severity of consequence & likelihood Implementation of Control Measures and Safeguards Driver training Behavioural observations Maintenance control (PtW) Vehicle / equipment inspections Etc.

15. PRISM Seminar, Bratislava Slide 15 Method 2: HF in major accident hazards

16. PRISM Seminar, Bratislava Slide 16

17. PRISM Seminar, Bratislava Slide 17 Procedure Checklist

18. PRISM Seminar, Bratislava Slide 18 Alarm checklist

19. PRISM Seminar, Bratislava Slide 19 Concurrent Task Analysis

20. PRISM Seminar, Bratislava Slide 20 Staffing assessment

21. PRISM Seminar, Bratislava Slide 21 Example: Automated continuous plant General control room duties difficult to assess Selected a manual task, and looked at links to control room activities e.g., communications, data entry & decision making Example � taking sample of reactor contents Error: fail to close circulation valve on sample cooler Consequence: Unrepresentative sample taken - status of reactor unknown Potential runaway reaction Recommendations: Ensure all operators understand importance of sampling Improve labelling of valves Investigate linking valves to sample point

22. PRISM Seminar, Bratislava Slide 22 Example: Design phase of new plant Multi-disciplinary team established during design phase Applied methodology to proposed design: Identified how plant will operate Identified design problems before too late Identified manning levels Most importantly�ensured employee involvement Example � connect road tanker to off-load point Error: driver connects to wrong point Consequence: Incompatible substance into storage tank - exothermic reaction Recommendations: Tanker drivers not allowed on site unaccompanied 2 x paperwork checks Off-load points locked

23. PRISM Seminar, Bratislava Slide 23 Method 1: Bottom up approach Pros: identifies main activities Covers many activities Quick Low manpower requirements Cons: Can be superficial Hard to find people when you need them Might miss certain root causes

24. PRISM Seminar, Bratislava Slide 24 Method 2: top down approach Pros: Very thorough Based on severity of MAH scenario Involves workers and supervisors High face validity Information rapidly gathered Cons: Time consuming Significant commitment from all involved Understanding of error mechanisms is required

25. PRISM Seminar, Bratislava Slide 25 Conclusions Human errors are predictable Task analysis approach helps identify causes and consequences. Complexity of operation should drive HEA More complex plant requires more complex process Commitment of time and people required for any aproach.

26. PRISM Seminar, Bratislava Slide 26 Any Questions? Jak�koliv ot�zky?