Frequently asked questions
SIL assessment of safety instrumented functions (SIF) – Calculations

Where can you find the reliability data you need to calculate failure probabilities?

Whatever the calculation method used (formulas derived from IEC 61508-6 or reliability methods), a certain amount of reliability data is required (failure rates, MTTR, etc.). Some of these data can be found in reliability databases such as OREDA (cf. Études des dangers : quelles banques de données ? [FIC 0539] ). Another alternative is to use data supplied by the equipment manufacturer (bearing in mind that these data are rarely based on feedback from on-site operation of the equipment).