Preventive maintenance
Maintenance done before a failure to lower its chance. In daily use it means fixed intervals; EN 13306 also counts condition-based and predictive work.
A job that a condition check or a forecast triggers is preventive too, not only the monthly service on a fixed interval. The types of maintenance page maps the whole family.
| In the standard | Preventive maintenance (EN 13306:2017, 7.1). Fixed-interval work is predetermined maintenance (7.2); condition-based (7.3) and predictive (7.4) work are preventive too |
| German | Präventive Instandhaltung (the standard's term), vorbeugende Instandhaltung (the term people search) |
| In SAP PM | Wartungsplan, which generates the work orders |
| Also called | PM; calendar-based or time-based maintenance for the narrow meaning |
Does preventive maintenance mean fixed intervals?
Often, but not by definition. Gulati's glossary defines PM as planned inspection and part replacement on a set interval, whatever the asset's condition. His chapter 4 also files condition-based work under PM, so even one book uses both meanings. EN 13306 calls fixed-interval work predetermined maintenance and keeps it as one kind of preventive work.
We recommend the standard's meaning for your own plans. Say "predetermined", "calendar-based", or "run-based" when you mean a fixed trigger, so nobody reads "PM" as a promise of condition checks.
EN 13306 also keeps "scheduled" apart. Preventive says the work comes before a failure. Scheduled says a date or usage count was set in advance. Opportunistic preventive work has no schedule: the team does it alongside other work or an event, to save cost or downtime.
What do teams get wrong about preventive maintenance?
- They treat it as a cure for every failure. Gulati reports that the airline studies behind RCM in the late 1960s found most failure modes random, not tied to time. A fixed interval prevents only the failures that grow with time or use.
- They never review the intervals. Gulati warns that calendar-based visits where nobody finds anything can be wasted maintenance money. If that happens, change the interval.
The Maintenance Manifesto puts the judgment in principle 3, "The best repair is the one you never need": spend more time preventing failures than fixing them, where it is effective. We recommend choosing the trigger for each failure mode, and not applying one calendar to the whole plant. Maintenance strategies compared shows how, and Start a preventive maintenance plan shows the first steps.
Related terms
- Condition-based maintenance
- Predictive maintenance
- Corrective maintenance
- Work order
- Maintenance, the hub for this topic
Sources
- EN 13306:2017, Maintenance: Maintenance terminology, CEN, 2017. Clauses 7.1 to 7.4, 7.12, and 7.13. This page explains the standard in our own words; the standard is the authority.
- Ramesh Gulati, Maintenance and Reliability Best Practices, 3rd ed., Industrial Press, 2021. Chapter 3 (glossary definition of PM), chapter 4 (calendar-based and run-based PM), chapter 8 (RCM history).
- Karl Liebstückel, Instandhaltung mit SAP S/4HANA, 6th ed., SAP PRESS, 2023, chapter 5 (Wartungsplan).
- Maintenance Manifesto, 2025, principle 3.