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2015 Trinity Dublin - Task risk management - hf in process safety

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Presentation to Post-Docs at Trinity College Dublin who were working on the TOSCA project

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2015 Trinity Dublin - Task risk management - hf in process safety

  1. 1. Tel: (+44) 01492 879813 Mob: (+44) 07984 284642 andy@abrisk.co.uk www.abrisk.co.uk 1 Task Risk Management Andy Brazier
  2. 2. 2 A bit about me Chemical engineer BSc - Loughborough University PhD - Edinburgh University 19 years working as human factors consultant 10 years self-employed Registered member of the Chartered Institute of Ergonomics and Human Factors (CIEHF) Associate member of Institute of Chemical Engineers (IChemE)
  3. 3. Experience Predominantly oil, gas, chemical, power and steel industries Human factors in major accident safety Design assessments Safety critical task analysis Staffing and organisational change Clients include Shell, BP, SSE, Centrica, Tata, Syngenta, Total, Maersk etc. 3
  4. 4. Places I have works – UK & Ireland 4
  5. 5. Places I have worked – further afield 5
  6. 6. Projects I have worked on but not visited 6
  7. 7. 7 Human factors and safety Up to 80% of accident causes can be attributed to human failures All major accidents involve a number of human failures Human factors is concerned with Understanding the causes of human failures Preventing human failures An important part of managing ‘major accident safety’
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  9. 9. 1. Annulus cement barrier did not isolate hydrocarbo ns Deepwater Horizon Explosions & Fire 2. Shoe track barriers did not isolate hydrocarbo ns 7. Fire and gas system did not prevent ignition 3. Negative- pressure test accepted - integrity not established 4. Influx not recognised until hydrocarbo ns were in riser 5. Well control response actions failed 6. Diversion of mud resulted in gas venting to rig 8. BOP emergency mode did not seal well Why?
  10. 10. Initially – did not achieve seal around drill pipe Negative pressure test accepted even though integrity had not been established Did not follow agreed test method Mis- interpreted data Crew had preferred method Operationa l instruction only broad guidance Did not recognise more liquid than expected No prediction available at time Rig crew expected to know how to perform test Previous experience Not aware of specified permit requiremen ts Did not realise constant high pressure indicated a problem Plausible explanatio n (bladder effect) Why? Why? Why? Why? Why? Why? Why?
  11. 11. Crew busy with other activities Influx not recognised until hydrocarbon was present in riser Instructions required constant monitoring - did not specify how Crew not monitoring well Other activities interacting with pits Pits not set-up for combined activities Mud pit levels not available to monitor Why? Why?Why?
  12. 12. Well control response actions failed to regain control of the well Slow to detect the problem Crew not properly prepared in required actions Protocols did not cover the scenario Crew had not been trained to deal with the event Why? Why?
  13. 13. Working in silos 14 QRA HAZOP Human factors
  14. 14. Problem with working in silos Generally Risks not understood fully Controls less effective and/or efficient Human factors Consequence of error not recognised in human factors studies Non-human factors people make inappropriate assumptions about how humans can failure Solutions/risk controls introduce additional human factors problems. 15
  15. 15. Extracting human factors from HAZOP Safeguards with human component Monitoring and control Alarm response Training or procedure??? Safeguard maintenance Tasks considered as potential causes of deviation Recommendations. 16
  16. 16. Issues with HAZOP and human factors Not a systematic study of human factors Human factors principles not always applied (correctly) HAZOP is already demanding without adding human factors But creating good links between HAZOP and human factors could be very beneficial. 17
  17. 17. 18 Risk profile Hazard detail Engineered Human Hierarchy Task or activity 1. Instrument 2. Alarm 3. Trip 4. Mechanical Task risk management 1. HMI 2. Deviation response 3. Emergency 4. Generic competence 5. One-off risk assessment 6. Automated Prioritise according to risk of MAH QRA, HAZID Identify deviations leading to MAH HAZOP, PHR ALARP Barriers Bowtie?
  18. 18. Task Risk Management Five stage process 1. High level screening 2. Identify tasks 3. Prioritise tasks for analysis 4. Analyse the most critical tasks 5. Use the findings 19
  19. 19. 1. Screening The parts of the system to focus your effort Hazardous Complex Critical to production Systems with potential for Major Accident Hazards (MAH) – all tasks are considered to be “safety critical.” 20
  20. 20. 1. Screening - hypothetical hazardous plant Process storage – yes Reaction plant – yes Pipeline – no Water treatment – partly Instrument air – no 21
  21. 21. 2. Identify tasks Possible approaches Skip the step – people often want to dive straight into task analysis Existing procedures – assume they cover all tasks Structured brainstorming – process drawing 22 Filters Duty/standby Pumps Duty/standby DP Alarms Lo LoLo Hi Trip Storage tank Delivery tanker Group exercise
  22. 22. 2. Identify tasks This step is very simple – but encourages a systematic approach Uses for task lists ‘Gap analysis’ of procedures, training/competence systems; ‘On the job’ training programmes; Workload estimates; Managing organisational changes. 23
  23. 23. 3. Prioritise tasks for analysis Possible approaches ‘Gut feel,’ experience or ‘normal’ risk assessment HAZOP, Process Hazard Review (PHR) etc. Scoring system (see OTO 092 1999 – HSE) 24 Hazardousness of system Ignition/energy sources Changing configuration Error vulnerability Impact on safety devices Overall criticality Low Medium High 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 0-3 4-8 9-15
  24. 24. 3. Prioritise tasks for analysis Benefits of scoring tasks at stage 2 Objective Demonstration of why tasks were selected for analysis – safety reports/cases Highlight ‘anomalies’ without carrying out a detailed task analysis 25 Microsoft Excel Worksheet
  25. 25. 4. Analyse the most critical tasks Task analysis is tried and tested – but negative perceptions Time and effort Only doing it to keep the regulator happy Discoveries from every analysis - if done ‘properly’ 26
  26. 26. 27 Connect tanker to delivery point 27272727272727 Transfer fuel from road- tanker to storage Preconditions •Delivery from approved supplier •Tanker located in unloading bay Transfer fuel using tanker’s pump Disconnect tanker from delivery point Confirm tanker is OK to offload Connect earth to tanker Connect vapour recovery hose Connect delivery hose between tanker & delivery point Open valves Check for leaks Start tanker’s pump Standby & monitor throughout When complete, stop pump and close valves
  27. 27. 4. Analyse the most critical tasks Group exercise – use a data projector People share experiences and concerns Accept procedure may not reflect reality Buy in to new methods An excellent training exercise for people involved Human error analysis Look at the task with ‘new eyes’ Identify where issues have been ‘glossed over’ 28
  28. 28. Consider consequence for each step if Omitted (not carried out) Incomplete Performed on the wrong object Mistimed (too early or late) Carried out at the wrong speed (too fast or slow) Carried out for the wrong duration (too long or too short) Performed in the wrong direction. 29
  29. 29. 30303030 Task Step Possible error Existing risk control measures Consequence Additional measures 30 Conne ct earth to tanker Action omitted - Potential for static discharge to act as source of ignition Failure to achieve an earth before starting transfer. Standard practice for all tanker operations . Consider installing interlocke d earth connectio n. Earth connectio n readily available.
  30. 30. 5. Use the findings ‘Engineer out’ error potential New projects – human factors integration plan Design reviews and system modifications Procedures High criticality – print, follow and sign every time Medium criticality – reference procedures Low criticality – generic procedures and guidance How do you manage the risks the risks of critical tasks that are performed frequently? Competence system How to perform tasks Understanding the risks 31
  31. 31. 5. Use the findings Continuous review – proactive and reactive Consider all stages when examining failures 1. Why is a task missing from the list? 2. Why was criticality not assessed correctly? 3. Was the task analysis correct? 4. Were the findings used? 32
  32. 32. Differential tasks vs activities Safety Critical Task (SCT) There is a clear start and finish There are discrete steps A change of status occurs Safety Critical Activity (SCA) where the critical aspects are: Timing (when to perform the task) Tools and equipment to be used Information presentation Decision making 33
  33. 33. Examples of SCT Node start-up and shutdown Starting main items of equipment Stopping same equipment often simpler Remove, calibrate and replace relief valve or bursting disk Leak or pressure test. 34
  34. 34. Examples of SCA & how to address Control/optimise process Human Machine Interfaces (EEMUA 191/201) Emergency response Emergency planning/staffing assessment Routine maintenance/inspection Planning and scheduling Competence of personnel, permit to work One-off tasks (e.g. temporary repair) Risk assessment and management of change. 35
  35. 35. SCT or SCA depends on circumstance Changing operating mode Manual stop or trip Check/calibrate transmitter Function test trip Maintain process equipment Contractor management Prepare plant for maintenance Normal shutdown? 36
  36. 36. Conclusions Linking human factors with other process safety activities has great benefits Linking all process safety activities should be the aim Differentiating SCT and SCA helps clarify the way forward Needs to be continuous and iterative Changing the approach to human factors is not the only requirement Process safety studies need to be modified to provide better date for human factors studies. 37
  37. 37. 38