An element's DC and SFF are calculated by an FMEA of each component or component group's failure modes and their effect without diagnostics, with enough information (block diagram, schematics, failure modes and rates with safe and dangerous splits) for confidence matching the SIL; classifying each mode as safe or dangerous, excluding no-effect and no-part failures; computing safe and dangerous failure rates (averaged where not constant); estimating the fraction of dangerous failures detected by diagnostics; summing total dangerous, detected dangerous and safe rates; and computing DC as detected dangerous over total dangerous, and SFF as safe plus detected dangerous over the total. The analysis covers every component (electrical, electronic, electromechanical, mechanical) needed for the safety function and every dangerous failure mode. Field data used must support the integrity requirement, with at least a 70 % single-sided lower confidence limit.
This control maps to 1 controls across 1 other frameworks. If you already hold one of them, the evidence you collected for it is the starting point here rather than new work.
Every mapping shown was judged rather than inferred from wording similarity, and the ones that failed review are published too. See the coverage reports and what was rejected.
The graph holds this control, the 1 it maps to, and the evidence behind each claim, over MCP and REST.