Failure Frequency
Failure frequency is the number of defined failures occurring during a selected period or operating exposure.
What this term means in maintenance
Failure frequency is the number of defined failures occurring during a selected period or operating exposure.
Possible measures
Failure frequency may be expressed as:
- Failures per month
- Failures per 1,000 hours
- Failures per cycle
- Failures per unit produced
- Failures per asset
Practical example
A machine experiences six failures during three months.
Frequency = Two failures per month
Use
It helps identify repeat failures, bad actors, trends, and changes in reliability.
Exposure
Calendar count alone may mislead when operating hours change significantly.
Common mistake
Changing the definition of failure between periods prevents valid comparison.
How this term differs
Failure Frequency is the count of defined failures during a selected period or exposure. It is related to Breakdown Frequency, Failure Rate, and Mean Time Between Failures, 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.
Failure Rate
Failure rate is the number of failures observed per unit of operating time for an asset or defined equipment population.
Breakdown Frequency
Breakdown frequency is the number of functional breakdown events occurring during a defined time or operating exposure.
Repeat Failure
A repeat failure is the recurrence of the same or closely related failure on an asset within a defined review period.
Failure Frequency FAQs
- What is failure frequency?
The number of defined failures during a period or operating exposure.
- How can it be expressed?
Failures per month, hour, cycle, unit produced, or asset.
- Why use operating exposure?
It allows comparison when equipment usage changes.