Presenting of failure probability assessment pattern by FTA in Fuzzy logic (case study: Distillation tower unit of oil refinery process)

Fault Tree Analysis (FTA) is an appropriate tool for failure analysis and failure rate determination. In some cases, it is difficult or even impossible to determine the relationships among the main factors of system failure. Moreover manual calculation of subsystem failure probability rate is hard or impossible. Also, in some situation for the lack of information about the process and main event obtained results are uncertain. This is where fuzzy tool can be best exploited. In this study with matching of FTA and fuzzy for determination of failure probability, we can obtain accurate and certain results. Refinery industry is one of the most dangerous industries in Iran and in some places it is located near the crowded cities. The distillation unit, as one of the most dangerous units in this industry, was evaluated by Fuzzy Fault tree analysis (FFTA) tool. The findings of this study can be used in risk management method.