Does the need for a new SIF come from a modification to the system, or how is it motivated? In the machinery sector, modifications requiring additional safety functions, would typically be considered "a significant modification", potentially requiring a new CE-marking, including an assessment of the safety system as a whole.

For complex components, i.e. MCUs, ASICS, etc. I usually go with the 50/50% rule for dangerous vs. safe failures, and so I dont need the specific failure modes. For simpler components, my main resources are: - IEC62061:2009 (Machinery specific) - FMD91 (Failure Mode/Mechanism Distributions, 1991, Reliability Analysis Center (RAC)) - There are more recent version from 2013 and 2016, but I think the old one is easier to use