What is PPM frequency?
PPM frequency is how often a maintenance task is carried out. It comes from statutory requirements, manufacturer recommendations, a schedule library, and the asset's criticality and condition.
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<img src="https://facilityoptix.co.uk/glossary/ppm-frequency/diagram.svg" alt="PPM frequency — diagram from FacilityOptix" width="880" height="620" loading="lazy">
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<a href="https://facilityoptix.co.uk/glossary/ppm-frequency">What is PPM frequency?</a> — diagram by
<a href="https://facilityoptix.co.uk">FacilityOptix</a>
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</figure>Where a frequency is set by law it is not a variable. Everything else is a judgement, and the judgement should be recorded so that a later reviewer can see it was made rather than inherited.
Over-maintaining is a real cost and a real risk: unnecessary intervention on working plant introduces faults. The optimum is not the most frequent option.
Frequencies should respond to evidence. An asset generating repeated reactive calls is telling you its interval is wrong, and almost nobody closes that loop.
In practice
A schedule where every task runs on the same cycle.
It is tidy and it conceals the only thing that matters: some of those tasks are there because a statute requires them, some because a manufacturer recommends them, some because an insurer asked, and some because the last FM thought it sensible.
Recording the source alongside the date is what lets somebody answer the question every FM is eventually asked — which of these can be stretched when the budget is cut, and which absolutely cannot.
Without that column the four kinds of obligation are indistinguishable, and a reasonable cost saving becomes a breach.
What goes wrong in practice
- Frequencies inherited from a previous contract with no basis recorded.
- Statutory and discretionary tasks at the same frequency and equally deferrable.
- Reactive history never used to review planned intervals.