Compressed air audit

The most expensive utility in most plants, and the one nobody meters.

Compressed air costs roughly seven to eight times what people assume, because the electricity going into the compressor is the only real cost and almost none of it ends up as useful work. Typical system efficiency is around ten per cent.

It is also the most leaked. A plant that has never had a leak survey commonly loses twenty to thirty per cent of generated air through leaks, and because a leak sounds like a working plant, nobody hears it.

An audit logs the system over a full production cycle including nights and weekends, surveys for leaks ultrasonically and tags them, checks the control strategy where there is more than one compressor, looks at pressure — every two PSI of unnecessary system pressure is about one per cent of energy — and checks whether anything is using compressed air for a job that a fan or a blower should be doing.

The weekend log is usually the most persuasive slide in the report. A plant that is shut and still drawing forty per cent of its weekday air is paying to inflate the building.

Industrial — the rest of it