Functional Safety Assessment & Audit

IEC 61511 safety life-cycle showing functional safety assessment stages, part of functional safety management

The IEC 61511 safety life-cycle and associated FSA stages

Linking requirements, argument and evidence for functional safety assessment and audit

Linking requirements, argument and evidence for FSA.


Functional safety assessment - FSA, is an independent verification by a competent, senior person, not involved with the stages of the system or facility being assessed. 

eFunctionalSafety has track history of assessing functional safety projects that need to conform to IEC 61511 / IEC 61508 for process safety, and IEC 62061 / ISO 13849 for machinery safety applications.

FSA should be conducted as early as the safety requirements specification stage (FSA 1), and is required at least once prior to start up (FSA 3).

If you need an independent assessor, eFunctionalSafety provides the planning and  FSA protocol that can help you through the process of closing key gaps to conformance. 

Our functional safety assessment checklist includes several hundred questions which relate to each IEC 61511 edition 2 and IEC 61508 edition 2 requirement, as applicable to the project scope.

eFunctionalSafety Functional Safety Assessment workflow

Functional Safety Assessment Procedure

A functional safety assessment (FSA) must only commence with a sound procedure and plan in place. The eFunctionalSafety typical methodology includes a series of "swim-lane" work processes which show the required steps and responsibilities of each party.

For a new-build or major modification project, our planning will include scoping all the proposed stages of FSA, the required inputs at each stage, and the expected results.

For a functional safety assessment of an existing SIS in operation, our plan will show the extent and scope of the assessment to be conducted on the existing system. Any exclusions will be fully clarified at the outset.

Read the blog: Is 100% functional safety conformance possible?

Where are you in the lifecycle - new or old?

For a new-build project we recommend that FSA is started as soon as the first SIL assessment has been completed. This may be before the safety requirements are fully developed, but from experience it is not wise to wait that long.

We use a combination of offline document review and site-based project team interviews to conduct our assessment

When the safety requirements specification is fully available, the FSA 1 activity can be finalised and formal reports can be produced.

A Stage 5 Functional Safety Assessment (FSA) was required for a safety instrumented system (SIS) undergoing upgrade on a Top Tier COMAH* chemical plant. We provided the lead assessor to scope, plan and deliver an independent assessment report.

We reviewed the safety instrumented system modification scope, including a revised hazard study, layer of protection analysis, safety requirements and the design changes to hardware and software of the system. The FSA stage 4 concluded with witnessed validation of the entire SIS prior to start-up.

eFunctionalSafety also completed a Stage 4 FSA by reviewing operations and maintenance procedures and proof test records for the existing system.

*COMAH - Control of Major Accident Hazards - UK legislation.

Functional Safety
Assessment & Audit

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