Fault tree analysis, FTA
Jan 22nd, 2015
Fault tree analysis, FTA
In our day to day practice we frequently see risk assessments methodologies being stretched to «fit the clients’ case», or, in other words, tools being selected to deliver results they were not designed for. This is a brief summary for the Fault tree analysis (FTA) one of the most common methodologies to evaluate a system against single or multiple initiating faults.
FTA is a top down, deductive failure analysis method in which an undesired state of a system is analyzed using Boolean logic (and/or gates) to combine a series of lower-level events. This analysis method is mainly used in the fields of safety engineering and reliability engineering to understand how systems can fail, to identify the best ways to reduce hazards or to determine (or get a feeling for) event rates of a safety accident or a particular system level (functional) failure. It has been shown in many occasions that the Boolean logic can be misleading, insofar a «correlation» may exist between failures of similar elements implemented to increase redundancy (false redundancy in nuclear, aerospace applications, for example).
FTA can be used to:
- understand the logic leading to the top event / undesired state.
- show compliance with the (input) system safety / reliability requirements.
- prioritize the contributors leading to the top event – Creating the Critical Equipment/ Parts/ Events lists for different importance measures.
FTA is a failure analysis tool. As such, it can be integrated in Quantitative Risk Assessments. FTA is a deductive, top-down method aimed at analyzing the effects of initiating faults and events on a complex system. This contrasts with failure mode and effects analysis (FMEA), which is an inductive, bottom-up analysis.
Tagged with: deductive failure analysis method, Fault tree analysis, FTA, reliability engineering, safety engineering, top down
Category: Consequences, Hazard, Optimum Risk Estimates, Probabilities, Risk analysis, Risk management
Leave a Reply