Operations and Maintenance
The Operations and Maintenance domain tests whether you can pick a maintenance strategy per asset, run a work-control system people actually use, and report performance with metrics that mean something.
Maintenance strategies
- Run-to-failure is legitimate only where failure is non-critical, cheap, and carries no safety, regulatory, or revenue consequence.
- Preventive (time- or usage-based) suits failure modes that are age- or cycle-related.
- Predictive / condition-based uses vibration, thermography, oil analysis, or ultrasound to trigger work from measured condition.
- Reliability-centered maintenance applies failure modes, effects, and criticality analysis so the cheapest effective strategy is chosen per failure mode. Criticality first, strategy second.
Work control discipline
Priority derives from impact (safety, regulation, revenue, occupants) crossed with urgency. Backlog is expressed in labour-weeks, not work-order count, because a count hides job size. PM compliance = PM occurrences completed ÷ PM occurrences due in the period.
Worked example
An asset has 8,760 available hours a year and logged 120 hours of downtime across 6 failures. MTBF = (8,760 − 120) ÷ 6 = 1,440 hours. MTTR = 120 ÷ 6 = 20 hours. Availability = 1,440 ÷ (1,440 + 20) = 98.6%. If MTTR doubles to 40 hours, availability falls to 97.3%. That shows why dispatch speed and spare-parts availability move the number more than wrench time on small failures.
Traps that cost marks
- Quoting MTBF as average repair time; that is MTTR.
- Reporting PM compliance by assets touched rather than occurrences due.
- Instrumenting every asset; the monitoring business case is criticality-weighted.
- Treating deferred maintenance as a saving rather than a shifting liability.