Minimal Cut Set
Definition
In a fault tree, the smallest set of simultaneously failing basic events that is sufficient to cause the top event. Identifies the most dangerous failure combinations for design and maintenance attention.
- Context
- Fault tree analysis
- Definition
- Smallest event set that causes the top event
- Use
- Identify critical failure combinations
- Field
- Root-cause and reliability analysis
Common questions
Why is a single-event minimal cut set more concerning than a multi-event one?+
A minimal cut set containing only one basic event means that a single failure alone, without any other coincidence, is enough to trigger the top event, making it a higher-priority target for design changes or added safeguards than a set requiring several simultaneous failures.
How does identifying minimal cut sets guide investigation or design work?+
Once every minimal cut set for a system is enumerated, engineers or investigators can rank them by likelihood and consequence, focusing corrective action or root-cause inquiry on the combinations that most plausibly explain the failure or pose the greatest ongoing risk.
Related terms
- 5-Whys
- An iterative questioning technique that moves from a symptom to underlying causes by asking 'why?' repeatedly until a systemic explanation is reached.
- Barrier Analysis
- A method that identifies the physical, administrative, and procedural barriers that should have prevented harm, and asks which barriers were absent, inadequate,...
- Fault Tree Analysis (FTA)
- A top-down, deductive Boolean logic model that works backward from a specific undesired top event through AND/OR gates to identify minimal cut...
- FMEA / FMECA
- Failure Mode and Effects Analysis is a bottom-up, inductive method listing what can fail in each component and the effect on the...
- Root Cause
- The fundamental, underlying deficiency from which the failure originated. Distinguished from immediate cause (the final physical event) and contributing factors. Root-cause analysis...