Common Cause Failure
A common cause failure occurs when one shared cause leads to the failure of two or more components, channels, or redundant systems.
What this term means in maintenance
A common cause failure occurs when one shared cause leads to the failure of two or more components, channels, or redundant systems.
Common shared causes
Examples include:
- Shared power loss
- Flooding
- High temperature
- Contamination
- Maintenance error
- Design defect
- Common software fault
- Fire
- Incorrect procedure
Practical example
Two redundant pumps fail because both suction lines are blocked by the same contamination source.
Why it matters
Redundancy may provide little protection when components share a vulnerability.
Controls
Possible controls include physical separation, diverse design, independent utilities, separate maintenance actions, and common-cause analysis.
Common mistake
Counting installed standby equipment as independent without reviewing shared power, controls, environment, and maintenance.
How this term differs
Common Cause Failure is multiple failures caused by one shared event or condition. It is related to Common Mode Failure, Single Point of Failure, and Redundancy, but these terms describe different records, measures, roles, strategies, or decisions and should not be used interchangeably.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
Redundancy
Redundancy is the provision of additional equipment, components, or paths so a required function can continue when one element fails.
Single Point of Failure
A single point of failure is one component, asset, or function whose failure can stop the entire required system because no effective alternative exists.
Reliability Block Diagram
A reliability block diagram is a visual model showing how component success or failure affects the ability of a system to perform its required function.
Glossary FAQs
- What does CCF stand for?
CCF stands for Common Cause Failure.
- What causes common-cause failure?
Shared power, environment, contamination, software, design, procedure, or maintenance error.
- Why does it matter for redundancy?
One shared cause can defeat several redundant components at the same time.