Compressed air leak detection: how to find the leaks costing you money

ByJack Braisher

Compressed air is one of the most expensive utilities in any factory or workshop, and a large share of it never reaches a tool. A system without an active leak detection programme typically loses 20 to 30% of its compressor output through leaks. That is air you have paid to compress, running straight out of fittings, hoses and joints, all day, every day.

The good news is that leaks are usually one of the cheapest problems to fix once you know where they are. This guide explains what leaks cost, where they hide, and how compressed air leak detection finds them.

How much do air leaks really cost?

Here is a simple worked example. Take a 22kW compressor running 4,000 hours a year, with electricity at 27.5p per kWh:

  • Annual running cost: 22kW × 4,000 hours × £0.275 = £24,200
  • If 25% of that output is lost to leaks: around £6,050 a year spent compressing air that goes nowhere

Your own figures will differ, but the principle holds for any size of system. Leaks also make your compressor work harder and run longer, which means more wear, more frequent servicing and an earlier replacement. On some sites, leaks are the reason a second compressor was bought in the first place.

Why you can’t hear most leaks

Large leaks hiss and get noticed. The problem is the hundreds of small ones that don’t. In a working factory, background noise masks almost everything, and many leaks sit in places nobody walks past: behind machines, in ceiling voids, at the far end of a pipework run or inside a cabinet. Individually they seem trivial. Together they add up to that 20 to 30%.

Where leaks usually hide

  • Quick release couplings and push in fittings, especially ones that are connected and disconnected often
  • Hoses that have cracked, perished or been crushed
  • Filter, regulator and lubricator units (FRLs) and their drains
  • Condensate drains that are stuck open
  • Threaded joints and old pipework, particularly on older galvanised systems
  • Valves and cylinder seals on production machinery
  • Air left feeding lines and machines that are no longer used

How ultrasonic leak detection works

Escaping compressed air produces high frequency ultrasonic noise, well above the range of human hearing. An ultrasonic leak detector picks up that sound and converts it into something the engineer can hear and measure, even over the noise of a busy production floor.

This means leaks can be pinpointed quickly and accurately without shutting anything down. Each leak can also be quantified, so you can see which ones are costing the most and fix those first.

What a leak detection audit includes

A proper audit goes further than tagging leaks. When we carry out a compressed air audit, we:

  • Survey the system with ultrasonic detection equipment to find and quantify leaks
  • Check whether working pressure is set higher than your processes actually need
  • Assess whether the compressor is correctly sized for your current demand
  • Provide a written report with findings prioritised by estimated waste, recommended actions and projected energy savings

For many customers the audit pays for itself within weeks of acting on the recommendations.

Quick wins you can make today

While a full audit gives you the complete picture, a few simple habits reduce waste straight away:

  • Switch off out of hours. If the compressor runs overnight or at weekends with no production, much of that output is feeding leaks.
  • Isolate unused lines. Close valves to areas and machines that are not in use.
  • Check your drains. A condensate drain stuck open can waste a surprising amount of air.
  • Review your pressure. Every extra bar of pressure increases energy use and pushes more air out of every leak.
  • Listen at quiet times. Walk the site at the end of a shift when machines are off. You will hear leaks you never notice during the day.

Keeping leaks from coming back

Leaks are not a one off job. New ones appear as fittings wear, hoses age and equipment is moved or added. The sites that keep waste low treat leak detection as a regular part of maintenance rather than a single clean up, often checking the system at each service visit.

Book a compressed air leak detection audit

We carry out compressed air leak detection and audits for sites across London and the Home Counties, on all makes of compressor and pipework, whether or not we supplied the equipment.

Not sure whether an audit is worth it? We offer a free initial walk round. One of our engineers will visit, look over your compressor and pipework, and give you an honest view of whether leaks are likely to be costing you money, with no obligation.

If your energy bills have crept up, or your compressor seems to run more than it should, get in touch to book your free walk round.

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