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Verify your Safety Instrumented System's readiness with a Stage 3 FSA, ensuring safe operation and compliance with design specifications.

Discover how a Stage 1 FSA can identify critical Safety Instrumented System (SIS) flaws early in the design process.

Updated April 2026 - A Functional Safety Assessment (FSA) is defined by the IEC 61511 standard as an “investigation, based on evidence, to judge the functional safety achieved by one or more SIS and/or other protection layers.” The ultimate goal of an FSA is to make the team confident that their instrumented safety system will reliably achieve the risk reduction needed. While many organizations understand the importance of FSAs, not everyone realizes the significant advanta

The 2nd edition of IEC 61511 now requires – by use of the word “shall” – that a Stage 4 Functional Safety Assessment (FSA) be conducted...

Functional Safety & Bayesian Networks Functional safety engineers fol low the ISA/IEC 61511 standard & perform calculations based on random hardware failures. These result in low failure probabilities, which are then combined with similarly low failure probabilities for other safety layers, to show that the overall probability of an accident is extremely low (e.g., 1E-5/yr). Unfortunately, such numbers are based on frequentist assumptions and cannot be proven. Looking at act

What might go wrong with an FSA, and what might you do to ensure that an FSA runs smoothly?

Inspired by “Conducting an Effective Functional Safety Assessment” presented at 2019 ISA PIC 2019—Process Industry Conference. by Greg...