What belongs on a preventive maintenance checklist

A preventive maintenance checklist that says "check belts, check bearings, check filter" produces a record that says somebody checked something. A checklist that asks for a number, states the acceptable range and says what to do on a fail produces a record you can act on a year later.

The five parts of a step that works

• •The action, as a verb: measure, replace, tighten, clean
• •The thing, named specifically enough to find it: "supply fan bearing, drive end"
• •What to record: a number, a yes or no, or a photograph
• •What counts as a pass, written on the step rather than known by one person
• •What happens on a fail, automatically, without anybody deciding

Ask for numbers, not opinions

"Belt tension acceptable" is one person’s judgement on one day. A deflection in millimetres is a fact you can compare with the last four visits. Numbers turn a checklist into a trend, and a trend is the only thing that lets you act before the failure.

Do not go mad with this. Three or four readings on a round is plenty. Twenty readings produce a form people fill in from memory.

Photographs at the step, not at the end

Ask for the picture at the moment the person is standing in front of the thing. A photograph requested at the end of a round gets taken of whatever is nearest, or not at all.

Make a fail raise the work

The most common gap in a preventive programme is a finding that was noticed and never fixed. That is worse than not noticing, because it proves you knew. If a failed step automatically raises tracked work, with the photograph and the location already attached, the loop closes because closing it is the easiest path.

Keep it to one visit

A checklist should cover what one person can do in one visit to one place. Rounds that span two plant rooms and a roof get split across two days by whoever is holding the phone, and the record ends up half true.

Review it after ten runs

Look at what the first ten completed runs actually recorded. The steps that are always skipped, always pass, or always get the same copied answer are telling you something. Fix or delete them before the checklist gets rolled out to forty buildings.