Ranking equipment by what its failure costs

Criticality ranking puts your equipment in order of what its failure would cost you, so that maintenance effort, spares money and monitoring go to the right places. Without it, effort is spread evenly, which means the equipment that stops the business gets the same attention as a store room fan.

Four factors, scored 1 to 5

• •Safety and environment: could failure hurt somebody or cause a release?
• •Business impact: does the building or the line stop, and for how long?
• •Redundancy: is there a standby, and will it actually start?
• •Repair difficulty: lead time on parts, specialist labour, access

Multiply or add, it matters less than being consistent. What matters is that safety dominates: anything scoring 5 for safety goes to the top regardless of the other three.

Run it as a workshop, not a survey

Get a technician, an operator and a manager in a room with the asset list and do it out loud. It goes faster than anybody expects, usually a few hundred assets in a morning, because most items are obviously low and the discussion is about the twenty in the middle.

Force the distribution

Everybody wants their equipment to be critical. Decide the shape before you start: roughly a tenth in the top band, a third in the middle, the rest low. Without that constraint you end up with half the estate marked critical, which is the same as marking none of it.

What to do with each band

• •Top band: condition monitoring where it fits, critical spares held, documented recovery plan, named person trained
• •Middle: preventive schedule tuned from failure history, spares identified but not necessarily stocked
• •Low: run to failure on purpose, with a decision recorded that this is deliberate

The redundancy trap

Standby equipment is only redundancy if it starts. A duty and standby pump pair where the standby has not run in two years is one pump with a decoration next to it. If a piece of equipment scores low criticality because of redundancy, the standby needs a proving test on the schedule, and that test is now itself critical.

Revisit it when the building changes

Criticality follows the use of the space. A plant room serving an empty floor becomes critical the day a data room moves in. Review the top band annually and after any significant change of use.