A Fuzzy Rule-Based Failure Mode, Effect and Critical Analysis (FMECA) for Control Valve Maintenance

Abstract

Control valves are one of critical equipment in oil and gas process plant. Control valve is highly engineered equipment, designed to very specific process parameters to serve as final control element in a process control loop. Failure of control valve might lead to catastrophic impact. Proper risk assessment is vital to optimized maintenance. This paper presents application of failure mode, effect and critical analysis (FMECA) for control valve using quantitative fuzzy based risks assessment. The main objective is to quantify the qualitative values of the risk level for each failure modes using pre-determined inference rules. The traditional FMECA RPN analysis is by multiplying three parameters: severity, probability and detectability irrespective of the degree of importance of each input which might produce similar value of RPN even the importance of the risk is different. A new method called Fuzzy rule-based was proposed to be used in this research for the control valve FMECA. Fuzzy RPN is utilized in order to identify highly critical failure mode as the focus of maintenance strategy. The result of Fuzzy-RPN criticality analysis is significantly different compare to traditional RPN. This due to Fuzzy-RPN utilized pre-defined expert rules, hence, the RPN number produced is considered more reliable.