Equipment Reliability
Equipment reliability is the probability that an asset will perform its required function without failure for a defined time under stated operating conditions.
What this term means in maintenance
Equipment reliability is the probability that an asset will perform its required function without failure for a defined time under stated operating conditions.
Elements of the definition
Reliability requires four things to be clear:
- Required function
- Defined time
- Stated operating conditions
- Acceptable performance
Practical example
A standby generator may be considered reliable when it starts and carries the required load whenever demanded during the review period.
What affects reliability
Reliability can be influenced by:
- Design
- Installation
- Operating load
- Environment
- Maintenance quality
- Lubrication
- Contamination
- Parts quality
- Human and procedural controls
Common reliability measures
Measures may include:
- MTBF
- Failure rate
- Repeat-failure rate
- Survival probability
- Failure-free operating time
Reliability versus availability
Reliable equipment fails less often. Available equipment is ready when required and can also benefit from fast repair and effective standby arrangements.
Common mistake
Using MTBF alone as the complete definition of reliability can hide failure severity, operating context, and different failure modes.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
Mean Time Between Failures
Mean Time Between Failures, or MTBF, is the average operating time between failures of a repairable asset during a defined period.
Failure Rate
Failure rate is the number of failures observed per unit of operating time for an asset or defined equipment population.
Maintainability
Maintainability is the ability of an asset to be inspected, serviced, diagnosed, repaired, and restored within a required time using defined resources and procedures.
Equipment Reliability FAQs
- What is equipment reliability?
It is the probability that an asset performs its required function without failure for a defined time under stated conditions.
- Is reliability the same as availability?
No. Availability also reflects restoration time and readiness when required.
- How can equipment reliability be improved?
Improve design, installation, operating conditions, maintenance quality, contamination control, and failure elimination.