Types of maintenance

The three types are not equal. Preventive maintenance has three kinds of its own, and predictive maintenance is one of them, not a fourth type. Words like reactive maintenance and run-to-failure are not types at all.

What are the types of maintenance?

• Maintenance
  • Preventivebefore a failure
    • Predeterminedon a fixed interval, with no check
    • Condition-basedwhen a check shows wear
      • Predictivewhen a forecast shows wear
  • Correctiveafter a fault
    • Immediatestarts at once
    • Deferredwaits under a set rule
  • Improvementmakes the machine better

Four questions sort every job:

1. Does the job make the machine more reliable, safer, or easier to maintain? Then it is improvement.
2. Does the job come before a failure or after a fault? Before a failure, it is preventive. After a fault, it is corrective.
3. If the job is preventive: do you check the machine first? With no check, it is predetermined. If a check decides the job, it is condition-based. If a forecast decides the job, it is predictive.
4. If the job is corrective: must it start at once? If yes, it is immediate. If a rule lets it wait, it is deferred.

Is predictive maintenance a separate type?

No. Predictive maintenance is condition-based maintenance with a forecast. An alarm at a fixed limit is condition-based, but it is not predictive. The work becomes predictive when a trend tells you when a part will reach its limit.

What do reactive maintenance and run-to-failure mean?

EN 13306 does not use these words. They map to its types like this:

You hear	It means	It is not
Reactive or breakdown maintenance	Immediate corrective work after a failure that nobody planned for	A fourth type
Run-to-failure	A written decision to do only corrective work on a machine	Neglect
Time-based or calendar maintenance	Predetermined maintenance	A check of the machine's condition

Which type should a machine get?

Choose the type for each way a machine can fail, and write the choice down. Maintenance strategies compared shows how. We recommend this because of two principles of the Maintenance Manifesto: "The goal is capacity assurance" and "The best repair is the one you never need".

Sources

• EN 13306:2017, Maintenance: Maintenance terminology, CEN, 2017. Clauses 7.1 to 7.4, 7.6, 7.9 to 7.11, and Annex A, Figure A.1. This page explains the standard in our own words; the standard is the authority. Buy it as DIN EN 13306:2018-02 from DIN Media.
• Ramesh Gulati, Maintenance and Reliability Best Practices, 3rd ed., Industrial Press, 2021, chapters 3 and 8 (reactive work and run-to-failure).
• Maintenance Manifesto, 2025, principles 2 and 3.