Safety Risk Assessment; Using Fuzzy Failure Mode and Effect Analysis and Fault Tree Analysis

The failure mode and effects analysis (FMEA) is a qualitative‎, ‎Inductive and effective method for detecting errors‎, ‎faults‎, ‎and failures in a system and fuzzy logic can improve that technique with more logical outputs‎. ‎Moreover‎, ‎the fault tree analysis (FTA) as a probabilistic risk assessment method is among the effective technique for calculating the probability of errors‎, ‎faults‎, ‎failures‎, ‎reliability and safety integrity level (SIL) verification resulting in certain events at higher levels‎. ‎The FTA also detects the main causes of events in complicated systems‎. ‎Although this technique appears to be time-consuming in systems with many diverse components‎, ‎it is considered a powerful tool‎. ‎In this paper‎, ‎the fuzzy FMEA analyzes the failure modes in a hypothetical system‎. ‎After that‎, ‎the process with the highest risk is selected as the input of an FTA‎. ‎According to the qualitative and quantitative analysis of FTAs‎, ‎a series of corrective actions will be proposed to reduce the failure probability‎.

Keywords:

Fault Tree Analysis (FTA) , Failure Mode and Effect Analysis (FMEA) , Qualitative Risk Assessment. Probabilistic Risk Assessment (PRA) , fuzzy number