Hidden Failure
A hidden failure is a loss of function that is not evident during normal operation and may remain undetected until another event creates demand.
What this term means in maintenance
A hidden failure is a loss of function that is not evident during normal operation and may remain undetected until another event creates demand.
Where hidden failures occur
Hidden failures commonly affect protective, standby, and monitoring functions.
Examples include:
- Standby pump fails to start
- Alarm does not operate
- Safety trip is bypassed or defective
- Fire detector is unavailable
- Emergency generator cannot carry load
- Relief device is stuck
Practical example
A standby pump remains idle and appears available. During failure of the duty pump, the standby fails to start because its control relay is defective.
Why hidden failures matter
A hidden failure may not create an immediate production loss, but it removes a layer of protection or redundancy.
How hidden failures are managed
Controls may include:
- Failure-finding tasks
- Proof testing
- Functional testing
- Alarm testing
- Standby rotation
- Self-diagnostics
- Redesign
Common mistake
Assuming standby or protective equipment is reliable because it has not been used can leave hidden failure undetected for long periods.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
Failure-Finding Task
A failure-finding task is a scheduled test performed to determine whether a hidden protective, standby, or emergency function is still available.
Redundancy
Redundancy is the provision of additional equipment, components, or paths so a required function can continue when one element fails.
Reliability-Centered Maintenance
Reliability-Centered Maintenance, or RCM, is a structured method for selecting maintenance and risk-control tasks based on asset functions, failure modes, consequences, and technically effective actions.
Glossary FAQs
- What is a hidden failure?
It is a loss of function that is not evident during normal operation.
- Where are hidden failures common?
Standby equipment, alarms, trips, detectors, and protective systems.
- How are hidden failures detected?
Through failure-finding tasks, proof testing, functional testing, and diagnostics.