Which part of the FTA structure typically contains the base events?

In a Fault Tree Analysis (FTA), base events are crucial because they represent the fundamental causes of system failures. These events are the lowest level of the hierarchy within the FTA structure and do not decompose further in the context of the analysis. They are often outlined at the bottom of the fault tree.

The top event signifies the undesired outcome or failure that is being analyzed, while middle events serve as intermediary steps that link the top event to the base events. Since base events are the foundational elements from which the higher events derive their logic, they are organized at the bottom level of the tree diagram. Understanding this structure is essential for reliability engineers, as it allows them to analyze all possible failure paths leading to failure and identify the root causes effectively.