In SIL verification, a PFDavg calculation reported with several decimal places can create a false sense of precision that deserves careful scrutiny. This mathematical precision does not demonstrate that we know the actual behaviour of the SIF to the same level of accuracy.

Failure Probability Is it very important to calculate very precisely the average probability of failure “PFDavg” of a Safety Instrumented Function? The short answer is "NO", and we will try to explain it below. The first thing to say is that Functional Safety is