Risk Analyzing of Equipment Failure by Using Fault Tree Analysis (Case Study: Gas Turbine Lubrication System)

Today, maintenance due to increased complexity in the production process and product variety has faced the change and caused the paradigm shift in implementation of maintenance strategies that in this procedure, maintenance strategies based on status has changed to strategies based on reliability. The aim of the study is evaluating of risk of equipment failure by a subset technique of possible risk assessment, which is called Fault Tree Analysis. Fault tree analysis is a technique based on failure and component-oriented, which started with an undesirable event, and by using a backward system process, determine the causes of this event. During this process, a fault tree is drawn to describe graphically the events and their relationship to the occurrence of the top event. Fault Tree is a qualitative model that offers a lot of useful information that cause an undesirable event. On the other hand, by using of Boolean algebra equations and by considering the relationship between the specified causes, quantitative analysis also can be done. In this study, emergency stop of gas turbine due to a malfunction in lubrication system as the top event (undesirable event) is considered and by considering the causes of failure to the occurrence of the event and drawing the fault tree, both quantitative and qualitative assessments on system failures, has been done. In addition, how to use the results of the risk assessment of failures in order to optimize the processes of maintenance management system has been presented.