When safety experts use a logic diagram to trace all the different combinations of equipment failures that could lead to a specific accident, what is that diagram called?

The diagram safety experts use to trace all the different combinations of equipment failures that could lead to a specific accident is called a Fault Tree Diagram. A Fault Tree Diagram is a graphical, top-down, deductive analytical tool. It begins with a single, undesired event, known as the top event, which represents the specific accident or system failure being analyzed. From this top event, the diagram works backward, systematically breaking down the event into its contributing causes and their logical relationships. These relationships are depicted using logic gates. An OR gate signifies that the event above it will occur if at least one of its immediate input events occurs; for instance, a pump might fail if its motor fails OR its power supply fails. An AND gate indicates that the event above it will occur only if all of its immediate input events occur simultaneously; for example, a critical error might happen if the primary control system fails AND the backup control system also fails. The inputs to these gates are other intermediate events or basic events. Basic events are fundamental failures or conditions that are not further developed or broken down within the diagram, representing the root causes or originating failures. By constructing a Fault Tree Diagram, safety experts can visually map out all potential failure paths that lead to the top event, identify critical combinations of failures, understand system vulnerabilities, calculate the overall probability of the undesired accident, and inform decisions on where to implement safety improvements or preventive measures.