Mitigation of Risk in CNG Station Using Fuzzy-Integrated Technique

In a CNG refueling station, identification of the risks associated with the complex operating systems and its prioritization is essential. This identification and prioritization will result in a proper understanding of the system by reliability analyst and maintenance engineer so as to frame appropriate maintenance planning. A fuzzy rule-based inference model taking into account the failure modes for risk ranking in FMEA to manage risks and make maintenance decisions is applied to a CNG station in this paper. One of the methods used for risk analysis is FMEA (Failure Mode and Effect Analysis) where we determine an RPN (Risk Priority Number) by multiplying the feature scores that are obtained from the degree of probability of occurrence (O), severity (S) and detection (D) without taking into consideration the relative importance of the factors. In the fuzzy approach, we use a linguistic variable for calculation of RPN. This method is so preferred because it provides us with unbiased judgment. The results obtained from this study show that the ambiguity in the conventional FMEA can be solved with a fuzzy approach, and conveniently discover potential failure modes and help in risk and reliability analysis of the system.