Error propagation and uncertainty analysis: Application to fault tree analysis

Abstract

AbstractFault tree analysis (FTA) is a widely used method for the evaluation of safety systems. FTA is based on modeling the behavior of a system by a combination of logic gates (AND, OR) in a logic tree that describes the system. Failure data of low‐level events are used to compute the frequency of the top event of concern. The failure rate data describe the failure of the system components such as pumps, valves, vessels, and instruments. All of the failure rate data are uncertain. This article presents a methodology for the evaluation of uncertainty in the top event of concern using propagation of error and uncertainty analysis methods. The fundamental theory is presented, and a simple fault tree uncertainty analysis is completed to demonstrate the methodology. The uncertainty analysis methodology allows for the identification of the components or assumptions that dominate the risk.