Failure Mode and Effect Analysis (FMEA) of Pipeline Ball Valves in the Offshore Industry

This article provides a practical method for applying failure mode and effect analysis (FMEA) on oil export pipeline ball valves. These valves have been selected for analysis because they are the largest, heaviest, and most important valves on topside platforms in the offshore sector of the oil and gas industry. FMEA is a systematic approach for evaluation and identification of potential failures associated with the design and operation of pipeline valves. A literature review is included to provide more detailed information about the operation, components, and failure modes of pipeline ball valves. Five failure possibilities associated with pipeline ball valves have been identified, including leakage from the body and seat of a valve during operation; lack of a proper factory acceptance test; valve body damage due to pipeline loads because of insufficient thickness; missing the finite element analysis on the body of the valves; and seat damages as a result of wax ingress. The severity and possibility of occurrence have been defined and assigned to each possible failure. A risk priority number has been calculated for each failure mode on a scale of 1-100. Two risk items have been recognized as critical, with score values between 50 and 60. The outcome of FMEA shows that seats of pipeline valves are the most exposed components at risk of failure. The most critical identified failure related to the seats is accumulation of wax in the seat area. The proposed solution is to apply flushing ports and double-isolate them with modular valves to minimize the risk of leakage to the environment. The second critical failure is related to damage of the valve body due to pipeline loads. Valve wall thickness calculations according to ASME Sec. VII Div. 02, as well as stress analysis on the valve body based on different loads, are proposed to minimize the risk of the second failure.