Glossary · Metrics & KPIs
The average time a non-repairable asset or component runs before it fails and is replaced outright.
MTTF is MTBF's counterpart for parts that get swapped, not fixed — a sensor, a bearing, a battery pack. Manufacturers publish MTTF ratings for exactly this reason: it tells a buyer roughly how long to expect before that specific part needs replacing.
The practical use is setting replacement intervals ahead of failure rather than after it — a battery rated for an MTTF of 18 months that gets swapped at 15 rarely causes an unplanned stop; one run to failure always eventually does.
Related terms
Reliabilytics calculates metrics like this from your live work-order and asset data — no spreadsheet required.
More in Metrics & KPIs
Asset Health Score
A single 0–100 score summarising an asset's condition, blending age, failure history, open faults and live sensor data.
Availability
The percentage of scheduled time an asset is actually capable of running, accounting for both breakdowns and planned stops.
MTBF (Mean Time Between Failures)
The average operating time between one failure and the next, for equipment that gets repaired rather than replaced.
MTTA (Mean Time to Acknowledge)
The average time between a fault being reported and someone actually acknowledging and taking ownership of it.
MTTR (Mean Time to Repair)
The average time it takes to fix a failed asset and return it to service, from the moment the fault is reported.
OEE (Overall Equipment Effectiveness)
A single score combining availability, performance and quality that shows how effectively an asset or line is actually running.
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