Fault Tree Analysis (FTA) is a systematic, graphical and quantitative method for analyzing the possible causes of a specific undesirable event, called the top event. The goal of FTA is to identify all of the possible combinations of failures and events that could lead to the top event, and to evaluate the likelihood or probability of each combination.
The fault tree is constructed by starting with the top event, which is represented as a rectangle, and then identifying the basic events that could cause the top event, represented as circles or ellipses. These basic events are then connected to the top event by means of logical gates, such as AND, OR, NOT, and XOR, which represent the logical relationships between the events.
Example 1:
Consider an example of a fault tree analysis of a system that has failed to provide a water supply to a community. The top event could be the "failure of the water supply system." Basic events could include: "pump failure," "pipe break," "power failure," and "control system failure." Using logical gates, we can connect the basic events to show how they contribute to the top event. For example, a "pump failure" OR a "pipe break" OR a "power failure" could lead to the "failure of the water supply system."
Example 2:
Another example could be a fault tree analysis of an aircraft crash. The top event is the "aircraft crash," and basic events could include "engine failure," "structural failure," "pilot error," and "air traffic control error." Using logical gates, we can show how the basic events could lead to the top event, such as "engine failure" or "pilot error" leading to the "aircraft crash."+
In conclusion, Fault Tree Analysis is a useful tool for identifying potential causes of complex failures and helps to evaluate the probability of each failure combination. It is widely used in various industries such as aerospace, nuclear power, petrochemical, and transportation, to name a few.