Fault-tree analysis is a method of analyzing system reliability and safety. It provides an objective basis for analyzing system design, justifying system changes, performing trade-off studies, analyzing common failure modes, and demonstrating compliance with safety and environment requirements. It is different from a Simplified Failure Mode and Effect Analysis in that it is restricted to identifying system elements and events that lead to one particular undesired event.
Many reliability techniques are inductive and concerned primarily with ensuring that hardware accomplishes its intended functions. Fault-tree analysis is a detailed deductive analysis that usually requires considerable information about the system. It ensures that all critical aspects of a system are identified and controlled. This method represents graphically the Boolean logic associated with a particular system failure, called the top event, and basic failures or causes, called primary events. Top events can be broad, all-encompassing system failures or they can be specific component failures.