Most industrial sites should treat a leakage survey as scheduled maintenance, not a one-off exercise. A 3mm hole in a 7-bar network can cost more than £1,000 a year in wasted electricity, before pressure instability, extra compressor run hours, and maintenance wear are counted.
Key Takeaways
- – Most sites should run leak surveys on a planned cycle rather than waiting for pressure complaints.
- – Survey frequency depends on compressor hours, energy cost, repair discipline and how quickly new leaks appear.
- – A good survey ranks leaks by cost, repair practicality and payback, not just by location.
Search Air, Atlas Copco Premier Distributor since 2002, works across Yorkshire and the East Midlands from Leeds, Sheffield, and Nottingham. This guide sets out the survey frequency we recommend, what the engineer should measure, and how the findings support cost, carbon, and compliance reporting.
The Practical Survey Interval
A full-system professional survey should be carried out annually, with quarterly or bi-annual ultrasonic checks on high-demand sites and in-house maintenance sweeps every 4 to 6 weeks. That cadence keeps leakage visible before it becomes normal operating loss.
Frequency Triggers
Use a simple layered interval. Maintenance teams should check obvious joints, couplings, drain valves, flexible hoses, damaged pipework, and audible faults every 4 to 6 weeks. Continuous production lines, older ring mains, and sites with unstable pressure should add quarterly or bi-annual ultrasonic checks.
- 4 to 6 weeks: visual and audible maintenance sweep.
- Quarterly or bi-annual: ultrasonic checks on high-demand systems.
- Annual: full professional survey with costed repair plan.
Retest Triggers
The annual survey should document compressor performance, pressure profile, end-use demand, leakage, repair priority, and payback. For a Doncaster fabrication site running 37 kW and 75 kW rotary screw compressors across two shifts, annual testing alone may not be enough. If operators respond to a pressure drop by raising generation pressure, the site pays for lost volume and a higher pressure setpoint.
Retest after new pipework, extra shifts, compressor replacement, or persistent low-pressure alarms, because each major change can alter demand and expose weak points. For South Yorkshire sites, our compressed air leak detection in Doncaster work is usually tied to annual service, pressure review, and repair planning.
Why Annual Testing Pays Back
A fundamental principle established by the British Compressed Air Society (bcas.org.uk) is that reducing the generation pressure of a compressor by just 1 bar, or 14.5 psi, results in a 7% saving in specific energy consumption. That saving only becomes realistic once the network has been sealed enough to run at the lower pressure.
Most unmanaged systems lose roughly 30% of their generated volume to leakage. In ageing or poorly maintained networks, that figure can exceed 40%, which means a compressor sized for production starts spending a large part of its duty cycle feeding faults.
Pressure Reduction Payback
Only 10% to 20% of the electrical energy fed into an air compressor reaches the point of use as functional pneumatic energy. The remaining 80% to 90% is lost mainly as heat of compression, which is why every escaped litre matters.
Across the United Kingdom, industrial compressed air generation accounts for approximately 10% of total industrial electricity consumption, representing the output of 1.5 power stations and contributing to over 5 million tonnes of CO2 emissions annually. The best payback often comes from repair and pressure reduction together, because fewer avoidable run hours also reduce compressor maintenance burden.
What the Engineer Measures on Site
A proper survey records where the fault is, how much volume it is losing, what it costs, and whether repair work can be completed without disrupting production. A tagged list is useful, but a quantified report is what turns testing into an investment case.
Report Fields
- Tagged location, operating pressure, shift pattern, and production state.
- Measured reading, calculated loss, annual cost, and kWh waste.
- Repair priority, access issues, shutdown requirements, parts, and retest outcome.
Escaping compressed air creates turbulence, and that turbulence emits high-frequency sound waves that are inaudible to human ears but measurable with the right instrument. Because high-frequency sound is very low energy, it does not penetrate solid objects but bounces and reflects off them. Skilled positioning matters in a noisy manufacturing facility.
The widely used frequency for compressed air fault detection is 40 kHz. The recorded dB level, combined with the system’s operating pressure, allows the software to calculate the corresponding CFM loss and assign a monetary value to the fault. Where access is difficult, air leak detection should include a walkdown before readings are taken.
Compliance and Reporting Pressure
The government mandates that participants now submit an ESOS Action Plan and provide annual progress reporting against their energy reduction commitments. For complete official guidance, businesses should refer to the Environment Agency’s portal: www.gov.uk/guidance/energy-savings-opportunity-scheme-esos (gov.uk).
For larger UK undertakings, survey findings are no longer just engineering notes. They can support board-level energy actions, carbon reporting, and evidence that identified savings have been acted upon.
Reporting Links
- ESOS: opportunity, proposed action, target date, and annual progress update.
- SECR: electricity reduction, carbon reporting, and reporting year.
- ISO 50001: audit method, energy baseline, action, and verification.
SECR requires businesses to publicly disclose their annual greenhouse gas emissions, Scope 1 and 2 with Scope 3 strongly encouraged, and underlying global energy use within their annual Directors’ Report. Compressed air repair records give you a practical measure taken during the reporting year.
What to Keep on File
Evidence Pack
Keep the dated survey report, readings, photographs, repair log, parts record, retest outcome, kWh calculation, pressure-change assumption, run-hour assumption, and board reporting extract together.
- Owner and target date.
- Annual progress update.
- Audit method, including ISO 11011, data logging, ultrasonic testing, ultrasound assessment, or AIRScan.
Repair Records
Your evidence file should contain the original survey report with tagged locations, quantified losses, photographs, and repair priorities. It should also include the repair record showing parts used, completion date, downtime needed, and whether a retest confirmed the fix. The energy record should show the cost calculation, pressure assumption, run hours, kWh saving, and reporting link.
The requirement for a mandatory action plan, with defined targets and annual progress updates via the government web portal, means businesses cannot keep delaying faults identified during surveys. A register without closed actions is weak evidence. This paper trail also protects the maintenance budget because it shows measured waste, completed repair work, verified reduction, and the remaining opportunity in one place.
Technology: Ultrasonic Detectors and Acoustic Cameras
In the last 12 to 24 months, the market has seen rapid adoption of acoustic imaging cameras such as FLIR Si124 and UE Systems UltraView. The camera overlays a visual “heat map” of the sound source in real time onto a digital image on the screen, allowing engineers to see leakage from several metres away.
Method Selection
Traditional ultrasonic instruments still have a place. They are accurate, portable, and useful for close inspection, especially when using a gross-to-fine method around fittings, valves, and machinery.
Atlas Copco describes AIRScan as a method for assessing supply, transmission, and demand in line with system audit principles, including data logging and targeted measurements. Their audit guidance (atlascopco.com) reflects the same direction we see on site: the report has to quantify demand, not just identify noise.
For Nottinghamshire, Derbyshire, and the M1 corridor, our compressed air leak detection in Nottingham work often combines ultrasonic testing with pressure review, because fixing the loss is only half the saving. The larger gain comes when the setpoint can safely come down.
FAQs
These are the questions we hear most from facilities managers, production engineers, and procurement teams when they are setting maintenance schedules. Testing frequency depends on production hours, system age, pressure stability, and repair discipline.
- Annual professional testing is the minimum for most industrial systems.
- Quarterly checks suit continuous production, pressure instability, or unexplained energy rise.
- In-house inspections should happen every 4 to 6 weeks.
How Often Should Compressed Air Be Tested?
Compressed air should be tested at least annually as part of a full system audit, with more frequent checks on continuous production sites. If pressure drift, compressor cycling, or unexplained energy use appears between audits, test sooner. High-demand Yorkshire and East Midlands plants often need quarterly ultrasonic checks because small faults become normal operating demand quickly.
Leak testing should also be done every 4 to 6 weeks in-house, especially around hoses, couplings, drains, and frequently moved equipment. Sites with older pipework, flexible hoses, or 24/7 operation should shorten the interval because losses can exceed 35% of total capacity. We see the strongest results when the maintenance team closes obvious faults between professional surveys.
How is Compressed Air Leakage Measured and Reported?
Compressed air leakage is calculated by measuring the sound level at the source, recording system pressure, and converting the reading into CFM or l/s loss. Modern software uses the dB level and pressure to assign annual kWh and cost values, then prioritises repair by payback. It is not the same as CPAP leak rate, which is a medical device measurement and does not apply to industrial networks.
For plant systems, the acceptable target is not a CPAP-style threshold but a managed leakage percentage. A well-run industrial system should drive losses well below the unmanaged 30% benchmark, document the actions taken, and retest completed repairs. Search Air covers Leeds, Sheffield, Nottingham, Yorkshire, and the East Midlands.
Call 0113 263 9081 to arrange a free air check, and we will tell you whether a spot check, full audit, or repair-led visit is the right next step for your site.