Fuzzy Bow-Tie Analysis: Concepts, Review, and Application

Abstract

Handling huge quantities of hazardous materials put the process industries into a variety of devastating risks. Fault tree (FT) and Event tree (ET) analysis methods are two distinct tools that are often used in process risk assessment. Bow-Tie analysis (BTA) as a comprehensive quantitative risk assessment (QRA) model, integrates the FT and ET in a common platform to establish a logical connection between causes of an undesirable event and their consequences. To conduct a QRA, it is necessary to estimate the failure probability of basic events and safety barriers. After estimating the severity of the potential consequences, the risk values should be estimated. Experts’ judgment elicitation is often employed in QRA due to the scarcity of crisp and precise data. This chapter intends to address an uncertainty aspect (i.e., subjectivity in expert judgment/knowledge) in BTA and applies the fuzzy set theory (FST) to deal with vagueness and imprecision associated with knowledge-based uncertainties. Furthermore, a comprehensive review of the application of FST and Fuzzy interface system in the Bow-tie model in safety and reliability engineering is presented. To demonstrate the applicability of the fuzzy set theory, a Bow-tie diagram of a distillation unit is developed and analyzed by integrating FST into the risk model.