Preventive vs Corrective Maintenance
Preventive maintenance is planned work carried out at set intervals or conditions to keep equipment running and prevent failures. Corrective maintenance is work carried out after a fault is found, to restore equipment to working order. Most organizations need both, but shifting the balance toward preventive work usually reduces unplanned downtime and emergency costs.
Key differences
| Preventive maintenance (PM) | Corrective maintenance (CM) | |
|---|---|---|
| Trigger | Calendar, usage or condition | A detected fault or failure |
| Planning | Scheduled in advance | Raised as a work request, then prioritized |
| Impact on operations | Planned, short interruptions | Often unplanned downtime |
| Cost profile | Predictable labor and parts | Can include emergency purchases and overtime |
| Typical KPIs | PM compliance, due PM failures, PM cost | Downtime, MTTR, repair cost, failures per equipment |
How to balance preventive and corrective work
- Build a complete asset register and classify assets by criticality.
- Create PM plans for critical assets first, based on manufacturer guidance and your failure history.
- Route every fault through a work request so corrective work is recorded.
- Review failures per equipment and repair versus PM effort regularly.
- Adjust PM frequency where failures repeat, and reduce it where it adds no value.
When to use preventive maintenance
- Assets whose failure is unsafe, disrupts critical services or is expensive to repair, such as chillers, fire pumps, generators and lifts.
- Assets with a predictable wear pattern, where manufacturer intervals or usage counters give a reliable schedule.
- Equipment covered by service-level or warranty conditions that require documented planned maintenance.
When corrective maintenance is unavoidable or acceptable
- Random failures that no reasonable inspection would have predicted.
- Low-cost, non-critical items where running to failure costs less than scheduled servicing, such as some light fittings or minor fixtures.
- Defects found during preventive inspections, which become planned corrective work orders.
Example: a multi-site facility in Saudi Arabia
Consider a facility management team running several commercial buildings in Riyadh. Chillers and air-handling units run for long hours through the summer, so the team schedules preventive maintenance for them before peak cooling demand and reviews PM compliance every month. Failures in non-critical items, such as a faulty light fitting or a dripping tap, are logged as work requests and handled as corrective work orders by priority. Comparing failures per equipment with PM effort then shows where preventive intervals should be tightened or relaxed. Teams that manage several sites this way often use facility management software to keep requests, work orders and KPIs in one place.
Maintenance strategies compared
Preventive and corrective maintenance are two of several strategies, and most programs combine them.
| Strategy | Trigger | Example |
|---|---|---|
| Corrective (run to failure) | After a failure | Replacing a failed light fitting |
| Preventive, time-based | A calendar interval | Quarterly chiller servicing |
| Preventive, usage-based | Operating hours or cycles | Servicing a generator after a set number of running hours |
| Condition-based / predictive | A measured condition | Servicing a motor when vibration exceeds a limit |
Condition-based and predictive maintenance need measurement data from inspections or sensors. Whatever the strategy, recording the work on work orders keeps each asset’s history complete.
Planned and emergency corrective work
Not all corrective maintenance is an emergency. Defects found during inspections can be planned and scheduled like any other job, while breakdowns of critical equipment need an immediate response. Separating the two shows how much corrective work is truly unplanned.
KPIs that show the balance
- PM compliance: preventive jobs completed on time as a share of jobs due.
- Planned vs unplanned work: the share of work orders scheduled in advance.
- Emergency work orders and overtime.
- Repeat failures on the same asset.
- MTBF and MTTR.
There is no universal target ratio; track the trend for your own asset classes.
Tracking PM and CM in Steady OMS
Steady OMS schedules preventive maintenance, tracks the PM performance meter and due PM failures, and handles corrective work through work requests and work orders. Its benchmarking view compares repair activity with PM effort, and its cost management KPIs separate repair cost from PM cost.
Frequently asked questions
Not always. Over-maintaining low-risk assets wastes labor and parts. The goal is to apply preventive maintenance where failure is costly or unsafe, and accept planned corrective work where it is not.
It refers to preventive maintenance that was due but not completed successfully. Tracking it shows where PM plans are not being followed.
Repairing a pump after it stops, replacing a failed light fitting, or fixing a defect found during an inspection. Corrective work can be an immediate response or a planned job.
Preventive maintenance follows a fixed schedule based on time or usage. Predictive (condition-based) maintenance is triggered by measured equipment condition, such as vibration or temperature.
Talk to Steady Solutions
Tell us about your sites, assets and processes, and our team will show you how Steady OMS fits your organization. You can also contact us directly or call +966 55 353 3314.