Fault Tree Analysis (FTA) is a systematic and graphical method used to analyze the causes of faults (failures) within a system. It starts with a top-level undesired event and works backwards to identify all possible causes or combinations of events that could lead to the undesired outcome. FTA is widely used in various industries, including engineering, safety engineering, reliability engineering, and risk management. Our methods and software are industry proven and they provide exact understanding of the combinations of events that cause the top level failure (called cut sets) and the failure frequency, and unavailability (down time) of each basic event and intermediate gate so that the importance of a particular path in the fault tree is easily understood.

Here is a sample FTA:

Fault Tree Analysis components:

1. Top Event: The top event is the undesired event or failure that is being analyzed. It is placed at the top of the fault tree diagram.
2. Basic Events: Basic events are the lowest level events in the fault tree that directly contribute to causing the top event. They are typically represented as nodes in the diagram and are connected to each other through logical gates.
3. Logical Gates: Logical gates (AND, OR, and NOT gates) are used to depict how basic events combine to cause higher-level events in the fault tree. These gates determine the logical relationships between events.
   • AND Gate: Represents that all input events must occur for the output event to occur.
   • OR Gate: Represents that at least one of the input events must occur for the output event to occur.
   • NOT Gate: Represents the negation of an event.
4. Analysis Process:
   • Constructing the Fault Tree: Start with the top event and systematically identify all possible events or conditions (basic events) that could contribute to causing the top event. Represent these events in the fault tree using logical gates to show relationships.
   • Quantitative or Qualitative Analysis: FTA can be performed qualitatively (to understand the logical relationships between events) or quantitatively (to estimate probabilities and failure rates of all basic events, intermediate gates and top level events if data is available).
   • Identifying Critical Paths: Identify critical paths or combinations of events that could lead directly to the top event. These paths highlight where interventions or improvements could be made to prevent the top event from occurring.
   • Risk Assessment: FTA helps in assessing the risk associated with the top event by understanding the contributing factors and their probabilities.
5. Benefits: Fault Tree Analysis provides a structured approach to understanding complex systems and their failure modes. It helps in identifying critical points of failure, designing effective preventive measures, and improving system reliability and safety including SIL verification activities.

FTA is often used in combination with other techniques like Failure Mode and Effects Analysis (FMEA) to comprehensively assess and manage risks within systems or processes. It is a powerful tool for engineers and analysts to systematically analyze potential failures and design robust systems that minimize the risk of failures leading to undesirable outcomes. Our fault tree easily extends to feed event tree analysis which can provide powerful “Level of Protection Analysis” (LOPA).