Approaches to integrating human factors in Seveso II safety cases

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Approaches to integrating human factors in Seveso
II safety cases

• Rob Cotterill
• DNV Consulting

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DNV and Safety Management

• 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

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The risk management agenda
EXTERNALLY DRIVEN
Societal
Political
INTERNALLY DRIVEN
Business Risks
Assets
Image
People
Product
Shareholders
Economic
Legal
EXTERNALLY DRIVEN
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Top Ten HF Issues

• Organisational change and transition management
• Staffing levels and workload
• Training and competence
• Fatigue from shiftwork and overtime
• Procedures
• HF in risk assessment and investigations
• Communications
• HF in design (e.g. control rooms)
• Organisational culture
• Maintenance error

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Understanding human failure
Slips
Skill based
Lapses
Errors
Knowledge based
Human errors are not random
Mistakes
Rule based
Routine
Violations
Situational
Exceptional
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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

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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

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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

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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.

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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.

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Error Analysis Sherpa technique
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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.

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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.

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Method 2 HF in major accident hazards

• COMAH (Seveso II) compliancedemonstration of
• Evaluation of potential human error
• Effectiveness of human interventions required to
  maintain control
• Establish awareness of human factors
• Line Management
• Engineering design
• Technology transfer
• Develop internal HF assessment methodology
• Apply to all types of activities on site
• Suitable for use by non-HF professionals
• Complement other risk assessment techniques

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Human Factors Method to Support COMAH
Before Assessment
Incorporate relevant results into Safety Report
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Procedure Checklist
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Alarm checklist
Engineering Equipment and Materials Users
Association (EEMUA), 1999, Alarm Systems A Guide
to Design, Management and Procurement. EEMUA
Publication No. 191. The Engineering Equipment
and Materials Users Association London
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Concurrent Task Analysis
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Staffing assessment
Health Safety Executive, 2001, Assessing the
safety of staffing arrangements for process
operators in the chemical and allied industries.
Contract Research Report (CRR) 348/2001. HSE
Books. See http//www.hse.gov.uk/research/frameset
/crr/index.htm.
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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

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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 importantlyensured 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

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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

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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

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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.

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Any Questions? Jakýkoliv otázky?
difference that counts

• DNV CONSULTING

Safeguarding life, property and the environment
rob.cotterill_at_dnv.com