Event Tree Analysis, usually the abbreviation ETA is used. It is a causal analytical technique which is used to evaluate the process and its events leading to a possible accident. ETA method was developed at the request of the nuclear industry following the accident at Three Mile Island plant. Principle of ETA is similar to the method of FTA with the difference that in ETA, events leading to failure are observed, not just a failure as in the case of the FTA. It is used especially in the area of risk management, quality management, and security management.
ETA method is based on the analysis of sequences of actions and events in the process leading to the accident, which is shown in a graphical logical model. ETA also considers a possible response of the security system and the human operator. Different accident scenarios are the result of ETA analysis.
Use of the ETA in practice: ETA method helps to systematically describe the series of activities of the security system. However, it is suitable for the analysis of any complex systems. It is used to identify and analyze the system, project and process weaknesses. The result is a set of recommendations to reduce the likelihood of accidents and reduce their consequences.
ETA method is part of IEC 62502 - Event Tree Analysis