The fault tree analysis (FTA), also known as a faultcondition tree analysis, is a systematic method for analysing the reliabilityof technical equipment and systems.
It is based on Boolean algebra and is used to determine theprobability of a system failure.
So if you want to know what danger your system poses, thisis the appropriate method.
Basic principle and application
The FTA uses a top-down approach, in which the possiblecauses and their logical links are determined based on an undesirable event(top event).
The error tree graphically displays these relationships,creating a tree-like structure.
The results are based purely on mathematics, and only thebasic elements influence the results.
Key features of the FTA:
Negative logic: the fault tree describes a failure function,where logical 1 represents a failure and logical 0 a functional system
Deductive approach: the analysis goes from the general tothe specific
Logical links: events are linked by AND and OR gates(actually only out of k-out-of-n gates)
Procedure
A fault tree analysis is typically carried out in thefollowing steps:
1. Determining the top event
2. System analysis and information gathering
3. Fault tree construction
4. Qualitative evaluation
5. Quantitative evaluation (if necessary)
When constructing the fault tree, all event combinations andprimary events that can lead to the top event are identified.
This requires an intensive examination of the system and itsinteractions. This alone can lead to risk reductions by identifying the maincauses.
Advantages:
• Systematic identification of failure causes
• Option for quantitative evaluation of failureprobabilities
• Visual representation of complex relationships
Challenges:
• Complexity of large systems
• Consideration of common cause failures
• Dependence on the quality of available data
Conclusion
The fault tree analysis is a powerful tool for thesystematic investigation of system failures. It allows to identify criticalpaths and vulnerabilities in complex systems and provides a basis for targetedimprovement measures to increase system reliability.
