Allocation of Safety Functions to Protection Layers

While it is a bit of a mouthful, “Allocation of Safety Functions to Protection Layers” describes reasonably well the objective of this task – which is to work out how much risk reduction is to be delivered by the various protection layers.

The SISSafety Instrumented System is just one of the protection layers identified. This task is often referred to as “SIL Determination” – while it is true that the SILSafety Integrity Level of any SIFSafety Instrumented Function ’s is found through this process, this label is not used by IEC 61511 and it doesn’t reflect how important the other protection layers (like relief valves) can be in delivering the required risk reduction to achieve tolerable risks.

As with H&RA, IEC 61511 doesn’t provide detailed guidance on which technique should be used for Allocation of Safety Functions to Protection Layers – since many different techniques are available and some are more suited to particular applications and industries than others. But it does require that this activity is subject to the full force of Functional Safety Management.

What =Method can do for you

• Experienced study facilitators for HazID, HazOp, LOPA and FTA studies.
• Independent verification when studies are delivered by others.
• Training and mentoring support for aspiring HazOp Study Leaders.
• HazOp Team Members training – either as a standalone training course or as part of our preparation for delivering a particular study.

Support for these activities are provided by =Method Process Safety Ltd.