Functional Safety Assessment (FSA): Do I need One?
Showing compliance with the 61511 phases and associated requirements may seem like a daunting process. So where does a Functional Safety Assessment fit with this demonstration and how does it all work?
Here are a few key points regarding Functional Safety Assessments (FSAs).
What is an Functional Safety Assessment?
The Functional Safety Assessment (FSA) is an investigation to determine if the safety function under study achieves the required level of functional safety to support a decision to either progress to the next phase of the lifecycle or remain in the same phase until all necessary measures are in place.
The work usually entails an audit of processes and procedures in place to ensure compliance with IEC61511 requirements, including verification for each stage of the lifecycle and validation of the full safety requirements. This will form the basis of the “Go ahead” or “Not ready yet” to move to the next phase of the lifecycle.
Why do I need to do an FSA?
Conducting an FSA is a mandatory requirement under IEC61511 prior to introduction of hazards, so before you get ready to press that Start button (Stage 3 in IEC61511) and operate your plant or system, you must confirm that Functional Safety has been achieved with regards to the necessary risk reduction for the system under study.
But the reality is that there is much more value in not restricting yourself to only that Stage.
Ok… so when do I need to do an FSA?
Typically there’s 3 key stages where an FSA should be conducted:
IEC 61511 Lifecycle Stage 2
Right after your Hazard studies and Risk Assessments are complete (e.g. HAZOP LOPA) and you’re getting ready to design your Safety Instrumented Functions (SIFs)
IEC 61511 Lifecycle Stage 3
Prior to introduction of Hazards [mandatory under 61511] once your system is validated as per Safety Requirements Specification (SRS)
IEC 61511 Lifecycle Stage 4
Once your plant or system has been operating for a few years, and sufficient data has been gathered to review the initial assumptions and in order to validate them or update them to reflect operational experience. These should be done periodically to ensure your assessments and your safety systems operating philosophy are up to date
Can anyone perform a Functional Safety Assessment?
An FSA should be done by an independent body in the form of either a person, department or organisation. The form of independence is affected either by the severity of the consequence the safety function is trying to protect against or the Safety Integrity Level (SIL) of the safety function, as detailed in the standard.
For example, looking at the Risk Assessment (e.g Layers of Protection Analysis, LOPA) was the consequence a minor injury? If so an independent person would suffice. Got a more serious consequence like single or multiple fatalities? It may be a good idea to consult a totally independent organisation.
An FSA can provide huge benefits in early identification of compliance gaps, and opportunities for streamlining processes making it easier to demonstrate compliance with IEC61511.
ESC Ltd has delivered Functional Safety Assessments for multiple industry sectors (e.g. O&G, Petrochem, Chem, Water) and has supported clients in optimising and delivering compliance with IEC61511 with a simple and cost-effctive approach.