From an event tree, accident sequences are obtained. Fault tree Fault trees are logical representations of the credible failures that can cause an undesired event to occur. The undesired event is stated at the top of the fault tree. The fault tree gates specify the logical combinations of basic events that lead to the top event. An initiating event is the first question that is asked on an event tree.
All accident sequences or undesirable outcomes begin with some type of initiating event.
Minimal cut set A minimum combination of failures needed to result in the occurrence of the event of interest. For a fault tree, the minimal cut sets represent ways in which a system can fail. For an accident sequence, minimal cut sets represent ways in which the sequence can occur. The Unreliability is the complement of the reliability, that is, the probability that the system does fail within a designated period of time and under specified operating conditions. Risk Risk is the potential of loss or damage resulting from exposure to a hazard.