Glossary
MTTR (Mean Time To Repair)
Plain-Language Definition
The average time taken to restore a failed asset or system to operational condition, measured from the time of failure report to the time of confirmed restoration.
Technical Context
MTTR = Total repair time / Number of repairs in period. Measured in hours. Includes diagnosis, parts procurement, repair, and testing. MTTR benchmarks vary by system: lifts (under 4 hours), HVAC (under 8 hours), electrical (under 2 hours for critical). Tracked in CMMS work order systems.
Why It Matters
MTTR directly impacts occupant experience and business continuity. A building with MTTR above 24 hours for critical systems has a reactive maintenance problem that needs investigation — likely skills, parts, or access issues.
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