Foutboomanalyses

Foutboomanalyses, commonly referred to in English as fault tree analysis (FTA), is a systematic, deductive method used to analyze safety hazards by examining how a specified undesired top event could occur. Originating in the 1960s, it was developed to support safety assessments in complex engineering systems and has since become a standard tool in industries where reliability and safety are critical, such as aerospace, nuclear power, chemical processing, and automotive engineering.

The method starts with a top event, the undesired outcome to prevent, and builds a hierarchical fault tree that decomposes this event into contributing causes. Components in the tree are connected by logic gates, typically AND and OR, with basic events representing elementary failures or external factors and intermediate events representing combinations of lower-level events. The qualitative phase identifies minimal cut sets, the smallest combinations of basic events that lead to the top event, highlighting the most relevant failure paths. The quantitative phase assigns probabilities to basic events and propagates them through the logic to estimate the probability of the top event. This often assumes independence between events unless dependencies are specifically modeled, and it may employ probability calculations or approximations for rare events.

Foutboomanalyses is frequently used for design reviews, safety cases, and regulatory compliance, and is often integrated with other risk assessment approaches such as event trees and probabilistic risk assessment. While powerful, the technique relies on the accuracy and completeness of the fault tree model; complex systems can yield large trees, and correlations or dynamic interactions between components can limit the method’s applicability without careful modeling.