Meeting IEC61508 and IEC61511 standards:
Hazard identification and risk assessment

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Functional Safety Management: Identifying Hazards and Assessing Risks

HIMA’s consulting business works with clients every day to develop frameworks within which to manage functional safety. Once the system has been created, a concept defined and the overall scope for the project or product specified, the first significant step in the functional safety lifecycle is identifying hazards and assessing risks.

There are numerous techniques for hazard identification: What if studies are a great way to analyze the hazards associated with change; Process Hazard Analysis, for example, focuses on the loss of containment or loss of control, while a hazard and operability (HAZOP) study includes the examination of P&IDs (piping & instrumentation diagram) or system drawings. Choosing the right technique to suit the type of facility being assessed and the stage of the project is a critical step in achieving a robust outcome.

"Choosing the right technique to suit the type of facility being assessed and the stage of the project is a critical step in achieving a robust outcome."

Once hazards are identified, inherent safety principles can be applied. How can the hazards be eliminated or minimized? At the earliest stages of a project it is possible to find alternatives and to challenge the design without significant cost impact on the project.

Where risks can’t be eliminated, the next step is to assess the risk to personnel, the environment, the asset and the reputational or commercial risk for each hazard. This assessment is done using techniques such as Layers of Protection Analysis (LOPA), risk graphs and bow-tie models. These techniques allow control measures to be identified to minimize the residual risk from the operation.

Control measures may be procedural controls, alarms, design features such as pressure relief, and safety-related systems. The allocation of risk reduction to the various control measures should be carefully considered, especially where an independent safety-related system is to be used to perform safety functions, as this will define the level of integrity required.

Once the safety integrity requirements have been defined for the safety functions, a safety requirements specification can be developed as input to the design process.

HSE Study: Hazard identification and risk assessment  

HSE Study: Hazard identification and risk assessment

Resource: Study by HSE, U.K.; Out of Control: Why control systems go wrong and how to prevent failure (2nd edition), (HSE ref: HSG 238).

This U.K. study cited above showed that the root cause of 44% of accidents was inadequate specification, often the result of weak hazard identification and risk assessment.

When you understand the hazards from the earliest stages of a project you can apply the principles of inherent safety, avoid serious design flaws and make design modifications without potentially facing a large commercial impact. When hazards emerge at a later stage in the project, they can prompt costly rework or even worse, a major incident leading to the loss of life, harm to the environment or large financial losses.

Ability to Influence Project Outcome  

Ability to Influence Project Outcome

Ability to Influence Project Outcome

Not only that, compliance with functional safety standards is much easier when they are integrated into the normal engineering and project management systems.

With HIMA’s functional safety experts at your side, you will have a high degree of certainty that the safety features are integrated into the design and that both capital expenditure (CAPEX) and operational expenditure (OPEX) are optimized.

Hazard identification and risk assessment

Hazard identification and risk assessment

Process:

  • Identify hazards
  • Analyze risks
  • Decide: is risk tolerable?
  • Allocate risk reduction to safety functions
  • Define safety requirements

Result:

  • Safety requirements integrated into the design, optimizing CAPEX and OPEX