Maintaining business premises
MTTR
MTTR (mean time to repair) is how long it takes, on average, to get a failed piece of equipment working again. It is worked out by adding up the time spent on all the repairs in a period and dividing that total by the number of repairs in the same period.
Also known asmean time to repair · average repair time · mean time to recovery · mean time to resolve
How it is calculated, with an example
The formula is an average: total time spent repairing in a period, divided by the number of repairs in that period. What matters is deciding beforehand from which moment and to which moment the clock runs, and not changing it afterwards; otherwise one quarter's figure cannot be compared with the next.
An example with made-up numbers. A bar's cold room fails three times in a quarter. The first repair takes 2 hours, the second 5 and the third 8. The MTTR for the quarter is (2 + 5 + 8) / 3 = 5 hours. If the following quarter comes out at 9 hours with the same number of faults, something has got worse: the technician is slower to arrive, a part is missing or the fault is a different one.
It is not the same as the time to pick up the report
Between someone seeing the fault and the cold room cooling again there are three stretches: until someone picks up the report, until they start work and until they finish. The first is the response time, the one an SLA usually sets; MTTR in the strict sense measures only the repair. Many businesses, however, call the whole span from the report MTTR, which in English is sometimes distinguished as mean time to recovery. Both measures are useful; mixing them in the same table is not.
Worth knowing
A low MTTR does not mean well-maintained premises. If the same fryer gets repaired quickly every week, the MTTR looks excellent and the problem is still there: it has to be read alongside MTBF, which says how often it fails, and alongside the other maintenance KPIs.
Sources
Related terms
- SLAAn SLA (service level agreement) is a written commitment to the time and quality with which a service is delivered. In a student residence it usually sets how many hours a maintenance ticket has to be picked up or resolved by type, and it is what decides what counts as overdue.
- MTBFMTBF (mean time between failures) is how long a repairable piece of equipment runs, on average, between one breakdown and the next. It is worked out by dividing the operating hours in a period by the number of failures recorded in that same period.
- Maintenance KPIsMaintenance KPIs (key performance indicators) are the few figures that show whether a business's maintenance is working: how long it takes to respond and to repair, how often each piece of equipment fails, how much of the time it is available, whether preventive work is done on time and how many faults come back.