Demons onstration of on of SFAI AIRP f P for or Regul ulator - - PowerPoint PPT Presentation

Demons

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• n of SFAI

AIRP f P for

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Regul ulator

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ajor

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Hazard F Facilities

Raghu Raman, Joel Leonard and Philip Skinner - Arriscar Pty Limited AIDGC Annual Conference, Sydney, 8 September 2017

Introduction

• Are ALARP and SFAIRP the same?
• Terms still not well understood
• Concept of “Reasonably Practicable”
• A holistic approach required for SFAIRP demonstration

Components of a Safety Case

• Detailed facility description, highlighting installed safety systems
• Formal Safety Assessment
• Hazard identification
• Consequence analysis
• Estimate of likelihood
• Estimation of risk
• Identification of Safety Critical Elements
• Safety management system
• SFAIRP demonstration

Interrelationships of Safety Case Components

What is meant by “Reasonably Practicable?”

What is meant by “Reasonably Practicable?”

• Old concept- Common law defined by Justice Lord Asquith in 1947
• UK Health and Safety at Work Act does not define any further
• Australian model WHS Act and Victorian OH&S Act describe what

needs to be considered

Model WHS Act, s18

…reasonably practicable, … means that which is, or was … reasonably able to be done …, taking into account and weighing up all relevant matters including: a) the likelihood of the hazard or the risk concerned occurring; and b) the degree of harm that might result from the hazard or the risk; and c) what the person concerned knows, or ought reasonably to know, about:

i. the hazard or the risk; and ii. ways of eliminating or minimising the risk; and

d) the availability and suitability of ways to eliminate or minimise the risk; and e) after assessing the extent of the risk and the available ways of eliminating or minimising the risk, the cost associated with available ways of eliminating or minimising the risk, including whether the cost is grossly disproportionate to the risk.

ALARP and SFAIRP

• SFAIRP and ALARP are the same (view of UK HSE)
• ALARP framework as developed by UK HSE has three bands.

“Intolerable” and “broadly acceptable” bands are not explicitly recognised in legislation

• Risk being in the tolerability region does not mean it is ALARP. It only

means that ALARP still needs to be demonstrated.

• SFAIRP demonstration requires specific attention in the Safety Report

ALARP Triangle

No defined regions for SFAIRP. Reasonably practicable principle applies.

A Holistic Approach (1)

• List where inherently safer design principles have been adopted in the

design (eliminate or reduce hazard)

• Compliance with approved Codes and Standards
• Good industry practice is implemented in the facility
• Comprehensive hazard identification and consequence assessment
• Risk analysis

A Holistic Approach (2)

• Integrity assessments
• Mechanical integrity (inspections, preventive maintenance)
• Safety instrumented systems integrity (SIL assessments)
• Safety Critical Control Measures (SCCM) identification and link back to

corresponding Major Incident being controlled

• Performance standards for SCCMs
• Performance standards based on Functionality, Availability, Reliability,

Survivability and Interdependence, with a section on how assurance is achieved

• Safety Management System (SMS) and associated procedures
• Maintaining performance standards through the SMS

How to Demonstrate SFAIRP

• Some form of risk assessment is necessary (Consequence and likelihood of each

MI) and risk ranking

• SFAIRP cannot be demonstrated without at the very least reference to additional
• r alternative control measures, especially for higher risk contributors
• Judge whether the costs of implementation of each additional measure is

justified against benefits gained

• On what basis should controls be rejected?
• Cost benefit analysis for disproportionality alone is not sufficient and cannot be

used to argue against implementation of relevant good practice (UK HSE)

Controls Reasonably Practicable or not?

The factors considered in reasonably practicable contained in s18

• The level of risk
• Severity and likelihood determined from the safety assessment
• What is known about the risk and means of controlling the risk
• Many sources of knowledge – incidents, SDS, standards etc.
• The availability and suitability of controls
• Often leads to the last point
• Is the cost grossly disproportionate?
• One way is to use cost benefit analysis

Societal Risk Assessment

• May be necessary due to encroachment of population centres closer

to MHFs

• F-N curves if quantitative risk is undertaken
• Approximate assessment using Risk Integrals may be appropriate if

detailed assessment not possible

• Incremental reduction in risk with each additional control measure

can be demonstrated

Some Elements of “Good Practice”

• A safety management system (overarching control)
• The facility designed to appropriate codes and standards for the

materials handled and operating conditions

• Personnel trained in the SMS and associated procedures and

competency certified

• Management has a feedback system to monitor safety performance

through inspections and audits

• Existing control measures are periodically reviewed to ensure they are

properly applied and still appropriate

Pitfalls in SFAIRP Demonstration (1)

• Risk analysis too generic and not specific to site and facility
• QRA undertaken in the absence of or using inappropriate “good practice”. Results

can be misleading and falsely optimistic

• Incorrect QRA – inadequate HAZID, incorrect assumptions, incorrect application
• f frequency band for failure rates
• Incorrect application of risk – Exposure time weighted individual risk alone is

used for assessing tolerability. Need to consider the likelihood and consequence

• f each event.
• Using cost-benefit analysis to justify already made decision not to implement

additional measures

Pitfalls in SFAIRP Demonstration (2)

• Not linking hazards to risk controls
• Not linking risk controls to measurable performance standards
• Considering risk below ’unacceptable level’ to be at ‘tolerable level’
• Inadequate consideration of human factors
• Cost-benefit analysis only done on most expensive options so they can

be rejected as being of disproportionate cost

Conclusions

In order to demonstrate SFAIRP, the following are necessary: 1. Good industry practice is implemented in the facility 2. A Safety Management System is developed, implemented and monitored 3. Comprehensive hazard identification and evaluation of control measures 4. Quantitative Consequence analysis 5. Risk analysis 6. Transparency and competency in the risk analysis and assessment 7. Risk is shown to be SFAIRP for each MI

Conclusions

8. Identify additional control measures 9. Show reasons for accepting or rejecting additional control measures

• 10. Link each safety critical control measure to corresponding hazard being

controlled

• 11. Performance standards and assurance for each SCCM
• 12. Link back SCCM performance to the SMS
• 13. Demonstrate that there is an audit/ feedback system to monitor & maintain

SCCM performance standards