felkedjaanalys

Felkedjananalys, often translated as "fault tree analysis" (FTA), is a top-down, deductive failure analysis in which an undesirable state of a system is analyzed using Boolean logic to combine a series of lower-level events. It is a graphical method used to determine the probability of a system failure or to identify the root causes of an existing failure. The process begins with a single undesired system state, known as the top event, and proceeds to identify all the possible lower-level events that could lead to it.

The analysis is represented by a tree diagram, where the top event is at the root. Branches extend downwards, representing contributing factors. These factors are linked by logical gates, typically "AND" and "OR" gates. An "AND" gate signifies that all input events must occur for the output event to occur. An "OR" gate indicates that at least one of the input events is sufficient for the output event to occur. The branches continue until they reach basic events, which are those that cannot be further decomposed or are considered to have a known probability of occurrence.

Felkedjananalys is widely used in safety-critical industries such as aerospace, nuclear power, and chemical processing to assess system reliability and identify potential hazards. It can be performed qualitatively, to understand the combinations of failures that lead to the top event, or quantitatively, to calculate the probability of the top event occurring by assigning probabilities to the basic events. The goal is to proactively identify and mitigate risks before they lead to system failures or accidents.