Are accident tree and fault tree analysis methods the same?

Are the accident tree analysis method and the fault tree analysis method the same?

The last edit to this post was made by ds66616 on 2018-9-21 at 22:58. Different opinions have been found: One view is that these are two translations of the same method. Fault tree analysis, also known as Accident Tree Analysis (FTA), is a deductive system safety analysis method. It starts with a specific accident or failure to be analyzed (the top event), and analyzes its causes layer by layer until the fundamental cause of the accident is identified, which is the bottom event of the fault tree. These underlying events, also known as basic events, have their data known or for which statistical or experimental results are already available. FTA can generally be divided into the following stages: (1) Selecting a suitable top event, analyzing the system boundaries and defining the scope, as well as determining the criteria for success and failure ； (2) Preparation for data collection: Gather information on processes, systems, and relevant data related to the event that needs to be analyzed ； (3) Construct the fault tree, which is the core part of FTA. By using the collected technical information, and with the assistance of design and operation management personnel, a fault tree is constructed ； (4) Simplify or modularize the fault tree ； (5) Qualitative analysis to determine all the minimal cut sets of the fault tree; when the number of cut sets is too large, probability truncation or cut set rank truncation can be applied through a program ； (6) Quantitative analysis: There are many tasks at this stage, which include calculating the probability of occurrence of the top event, that is, the point invalidity and interval invalidity of the system. In addition, importance analysis and sensitivity analysis must also be carried out. The accident tree analysis method can be used for the reliability and safety analysis of complex systems such as intercontinental missiles (nuclear power plants) and other various types of systems, as well as for the reliability analysis of safety management in various production processes and the analysis of casualties.

This post was last edited by ds66616 on 2018-9-21 23:02. Another way to put it is that Fault Tree Analysis (FTA) is a top-down deductive failure analysis method that uses Boolean logic to combine lower-level events in order to analyze the undesirable states within a system. Fault tree analysis is primarily used in the fields of safety engineering and reliability engineering to understand the causes of system failures, to identify the best ways to reduce risks, or to determine the probability of a certain safety incident or specific system failure occurring. Fault tree analysis is also used in aerospace, nuclear power, chemical processing, pharmaceuticals, the petrochemical industry, and other high-risk sectors, as well as for risk identification in other areas such as the failure of social service systems. Fault tree analysis is also used in software engineering, for error detection, and is closely related to techniques for eliminating the causes of errors. In the aerospace field, the broader term “system failure state” is used to describe the fault tree ranging from undesirable underlying conditions to the ultimate failure event. These states are classified according to the severity of their outcomes. As a result, the most severe scenarios require the most comprehensive fault tree analysis to address them. Such “system failure states” and their classifications were previously handled through functional hazard analysis. https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D220/sign=e4dda38648a98226bcc12c25ba83b97a/622762d0f703918faff51c395a3d269759eec418.jpg Image 1: Diagram of fault tree analysis

This post was last edited by ds66616 on 2018-9-21 23:03. Another view is that the main difference between an event tree and an accident tree is as follows: 1. An event tree is a process of deriving conclusions from causes; it is a forward logical reasoning process. An accident tree, on the other hand, analyzes the causes from the results in order to identify the root events that lead to an accident; it is a process of reverse logical reasoning. The origin of Fault Tree Analysis 1 Fault Tree Analysis (FTA) is one of the important analysis methods in safety systems engineering. It utilizes logical reasoning to identify and assess the hazards associated with various systems; it enables not only the identification of the direct causes of accidents but also a deeper understanding of their underlying causes. Using it to describe the causal relationship of an accident is intuitive and clear. 2 It features clear thinking and strong logic, enabling both qualitative and quantitative analysis. It is commonly used in the field of risk management for identifying and measuring corporate risks.

Event Tree Analysis: Event Tree Analysis (ETA) is a commonly used inductive reasoning method in safety systems engineering. It originated from Decision Tree Analysis (DTA) and is a method for identifying hazard sources by deducing possible consequences starting from an initial event, in accordance with the chronological sequence of an accident’s development. This method uses a tree diagram known as an event tree to represent the logical relationship between a certain type of accident that may occur in a system and the various factors that lead to that accident. Through qualitative and quantitative analysis of the event tree, the main causes of accidents are identified, providing a reliable basis for determining safety measures in order to predict and prevent such accidents. Currently, event tree analysis has been applied from the aerospace and nuclear industries to fields such as power generation, chemicals, machinery, and transportation. It can be used for fault diagnosis, identifying weak points in systems, ensuring the safe operation of systems, and enabling the optimal design of such systems. Functions of event tree analysis: 1. ETA enables the preemptive prediction of accidents and safety hazards, the estimation of potential consequences of such accidents, and the identification of the most cost-effective preventive measures and methods. 　 2. It is very convenient and clear to analyze the cause of an accident using ETA afterwards. 3. The analysis data on ETA can serve as intuitive materials for safety education, and it also helps in devising preventive measures for similar accidents. 4. When a large amount of accident data has been accumulated, computer simulation can be used to make ETA’s predictions of accidents more accurate. 5. In terms of safety management, using ETA to make decisions regarding major issues offers advantages that other methods do not possess.

Without systematic training, it is impossible to explain this matter thoroughly; one can only list the information above for reference.

Thank you! Event trees are not discussed here. I didn’t originally want these excerpts from the internet, but thanks anyway for your effort:handshake