Glossary category
Maintenance KPIs & performance
Metrics for evaluating reliability, repair duration, and asset performance. All 22 terms are available as direct static HTML links.
- 01
MTTR (Mean Time to Repair)
The average time required to repair a failed asset and restore its function.
→ - 02
MTBF (Mean Time Between Failures)
The average operating time of a repairable system between two defined failures.
→ - 03
OEE (Overall Equipment Effectiveness)
A metric combining the availability, performance, and quality rate of production equipment.
→ - 04
Asset criticality
A ranking of how important an asset is to production, safety, or cost, used to prioritize maintenance attention and strategy.
→ - 05
Backlog weeks
The maintenance backlog expressed as a number of weeks of available labor capacity needed to clear it.
→ - 06
Downtime
The total time an asset is not performing its intended function, regardless of whether the stop was planned or unplanned.
→ - 07
Emergency work percentage
The share of total maintenance work that was carried out as an unplanned emergency response, rather than planned or scheduled.
→ - 08
Failure rate
The number of failures observed per unit of time or operating cycles, for a defined population and observation period.
→ - 09
First-time fix rate
The share of maintenance jobs resolved in a single visit, without needing a return trip or follow-up work order.
→ - 10
Maintenance cost
The total direct and indirect expenditure attributable to maintaining assets: labor, parts, contracted services, and overhead.
→ - 11
Maintenance cost as percentage of RAV
Maintenance cost expressed as a percentage of the replacement asset value it protects, allowing comparison across sites or asset classes of different size.
→ - 12
Maintenance productivity
The ratio of useful maintenance output achieved to the labor or resources spent achieving it.
→ - 13
Mean Down Time
The average duration of a single downtime event, from stop to resume, across a set of observed events.
→ - 14
Mean Time to Failure
The average time a non-repairable item operates before it fails, once, for good.
→ - 15
Planned downtime
The measured time an asset is stopped for a scheduled reason, such as maintenance, changeover, or a planned shutdown.
→ - 16
PM compliance
The share of scheduled preventive maintenance tasks completed on time, out of all preventive tasks due in a period.
→ - 17
Schedule compliance
The share of all scheduled maintenance work (preventive and other planned jobs) completed within its assigned time slot.
→ - 18
Spare parts fill rate
The share of spare-parts demand that can be met immediately from available stock, without a delay for procurement.
→ - 19
Unplanned downtime
The portion of downtime caused by an unexpected failure, as opposed to a scheduled, agreed stop.
→ - 20
Uptime
The total time an asset is actually performing its intended function, the complement of downtime.
→ - 21
Work order aging
A measure of how long individual work orders have remained open, used to identify stalled or overlooked jobs.
→ - 22
Wrench time
The fraction of a technician's paid hours actually spent doing hands-on maintenance task execution, excluding travel, waiting, and admin.
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