Fault tree analysis (FTA) is a top-down, deductive failure analysis in which an undesired state of a system is analyzed using boolean logic to combine a series of lower-level events. This analysis method is used to understand how systems can fail, to identify the best ways to reduce risk, and to estimate event rates of a safety accident or a particular system level (functional) failure.
1st Example of Fault Tree Analysis (FTA)¶
Procedure¶
Communte to work or school avoiding injury from a traffic accident or other hazards.
2nd Example of Fault Tree Analysis (FTA)¶
Procedure¶
A batch reactor is used to complete a reaction needed for the benefit of others. The reactor process has the following processing steps:
The reactor is filled with the raw material, a somewhat toxic material.
The reactor is heated to the desired temperature (100 F).
The reactor is pressurized to the desired pressure (20 psig).
Reactant B is slowly added to the reactor. An exothermic reaction occurs and the jacket must begin to cool the reactor to maintain the desired temperature.
The reaction proceeds at a given reaction rate at that temperature and pressure until all of the reactant B has been added.
The reactor is cooled to room temperature and the product is removed.
Some Hazards¶
Product C has a low boiling point and is toxic. If the reactor is not cooled properly, the product will vaporize and escape from the reactor.
If stirring is not maintained, the reaction will not proceed at the desired rate and the reactor will overheat.
Reactor is used for multiple products
(a)Batch Reactor
Figure 1:Image of the batch reactor credit to: https://
Combination of FTA and FMEA:¶
An accident investigation prior to the accident
Example start on an FTA: (lower left is ‘Blades fall off’)
Figure 2:Example Fault Tree Analysis
Example start of the FMEA/ Hazards Analysis
Figure 3:FMEA Example
- Guymon, C. (2025). Foundations of Spiritual and Physical Safety: with Chemical Processes.