Industrial Compressed-Air Leak Detection: A Practical Program for Reducing Factory Energy Waste

Compressed air is essential to many manufacturing processes, but it is also an often-overlooked source of factory energy waste. Air compressors may continue running to replace losses that are distributed across production lines, hoses, fittings, valves, drains, and end-use devices. Because production can continue normally, the cost of those losses is easy to miss.

A reliable leak program is more than finding hissing fittings. It includes preparation, detection, measurement, repair, documentation, and follow-up. Understanding industrial compressed-air solutions from Atlas Copco can also help teams place leak work in the broader context of compressor controls, air treatment, distribution, and system efficiency.

The goal of industrial compressed-air leak detection is not to produce an impressive list of detector readings. It is to create a repeatable process that identifies losses, connects them to operating conditions, assigns practical repairs, and verifies whether the work improved the system.

Why Compressed-Air Leaks Deserve a Formal Program

A leak increases the amount of air the compressor must produce. Depending on the control strategy, this can increase compressor runtime, loaded operation, starts and stops, or operation of additional compressor capacity. The resulting effects may include higher electricity use, reduced pressure stability, greater compressor and dryer loading, and additional maintenance demand.

One visible leak is only one point in a larger system. Losses may occur at compressor-room headers, distribution drops, quick-connect couplings, flexible hoses, regulators, filters, automatic drains, pneumatic valves, cylinders, vacuum generators, blow-off devices, and temporary connections. A facility can repair an obvious fitting while other losses continue across several production areas.

A leak can be costly even when production appears unaffected. The compressor may compensate by running longer, while the pressure at a distant point of use remains acceptable. In other cases, operators may increase system pressure to mask low pressure at an end use, increasing the flow through existing leaks and adding stress to components. These conditions make compressed-air system maintenance a plant-wide reliability and energy issue rather than a minor housekeeping task.

Prepare Before Starting an Industrial Leak Survey

Define the survey boundary

Start by identifying the equipment and piping included in the survey. The boundary may include compressors, dryers, receivers, main headers, branch lines, drops, points of use, and isolated systems serving particular machines or rooms. Note any systems that operate at different pressures or use separate compressor controls.

Create or update a simple equipment map. It does not need to be a detailed engineering drawing, but it should show major equipment, production areas, branch lines, and location identifiers. Assigning identifiers such as area, line, machine, and component number makes later work orders and verification much more reliable.

Choose the right operating conditions

Decide whether the survey will occur during production, during a planned non-production period, or in both conditions. A production survey can reveal leaks that matter under normal demand and can show how end-use devices behave. A non-production survey can expose background leakage after production loads are removed. Neither condition represents the entire system by itself.

Record the operating schedule, compressor pressure, active compressors, receiver status, production state, and any unusual demand. Detector readings and flow estimates should always be associated with these conditions. A reading taken at one pressure and production load should not be treated as a universal value for the same component under every operating condition.

Plan safety and coordination

Coordinate the route with maintenance, operations, and area owners before entering production spaces. Apply lockout/tagout where isolation or disassembly is required. Use hearing and eye protection appropriate to the area, and account for hot compressor surfaces, rotating equipment, moving machinery, elevated work, and restricted access.

Some facilities also have sanitation, cleanroom, food-processing, or contamination-control requirements. Confirm acceptable inspection tools and access methods in advance. Do not interrupt air to a critical machine without authorization, and plan repairs around production constraints rather than treating the survey as an independent activity.

How Industrial Compressed Air Leak Detection Works

Ultrasonic detection

Escaping compressed air produces high-frequency turbulence that ultrasonic instruments can detect, even where audible plant noise is substantial. Ultrasonic leak detection is often effective for locating small leaks in fittings, valves, hoses, and connections when the inspection is performed methodically.

Move through the area in a consistent route. Begin with a broad scan, then reduce the instrument sensitivity as the suspected source is approached. Compare nearby components, change the inspection angle, and confirm the exact source rather than recording the loudest signal in a group of fittings. Reflections from metal surfaces and airflow from nearby equipment can create misleading readings.

Ultrasonic detection identifies a leak signature; it does not automatically measure the exact volume of air lost. Quantification requires a calibrated instrument, a suitable conversion method, a controlled test, or system-level metering. Detector readings are useful for locating and ranking leaks, but they should not be reported as verified energy savings without an appropriate calculation.

Pressure decay and isolation testing

Pressure decay testing can help assess leakage in an isolated section after production loads have been removed. The section is isolated with suitable valves, brought to a defined starting pressure, and observed for a specified period. The pressure change is then interpreted using the isolated volume and test conditions.

Results depend on valve isolation, receiver and pipe volume, starting pressure, test duration, temperature, and the accuracy of the pressure measurement. Air trapped in connected equipment or valves that do not fully close can distort the result. Use a consistent procedure and document the test boundary so results from different surveys can be compared.

Metering and compressor-load analysis

Flow meters, compressor controls, compressor run-time records, and loaded-versus-unloaded operation can support system-level estimates. For example, a stable non-production period may show the background demand associated with leaks and permanently connected equipment. Compressor performance data can then help estimate the energy needed to supply that demand.

These methods complement rather than automatically replace point-by-point inspection. System-level data may show that losses are significant but cannot identify every failed fitting or drain. Conversely, a component survey may identify many leaks without showing how compressor controls and changing production demand affect total energy use.

Visual and audible checks

Simple inspection remains valuable. Look for damaged tubing, loose or misaligned fittings, cracked hoses, failed automatic drains, open blow-off devices, and unused branches that remain pressurized. Check for inappropriate uses of compressed air, such as open-ended cleaning, cooling, drying, or agitation where a safer and more efficient method may be available.

A Step-by-Step Leak Survey Workflow

1. Prepare the survey. Confirm the boundary, route, safety requirements, access permissions, operating schedule, and equipment map.
2. Collect baseline data. Record compressor status, system pressure, production state, flow if available, loaded and unloaded behavior, and relevant operating hours.
3. Plan the route. Move from the compressor room through headers, branches, drops, end uses, and isolated systems. Use the same route during future surveys where practical.
4. Inspect each component. Scan fittings, hoses, valves, regulators, filters, drains, cylinders, quick-connects, blow-off devices, and temporary connections. Include areas that are difficult to hear or access.
5. Tag each suspected leak. Assign a unique asset or location ID. Record the component type, detector reading or observation, pressure, operating state, and access requirements.
6. Confirm the source. Adjust sensitivity, compare adjacent components, use a suitable secondary check, and make sure the signal is not caused by airflow from another leak.
7. Classify the condition. Consider estimated cost, safety or quality impact, production risk, repair difficulty, recurrence risk, and whether the leak can be isolated immediately.
8. Assign the repair. Create a maintenance work order with an owner, required parts, isolation needs, priority, target date, and any production coordination requirements.
9. Close out and verify. Record the date repaired, work performed, replacement component, post-repair detection result, and verification status. Add a photograph or equipment-map reference when it will help the next technician find the location.

Useful records typically include asset ID, location, component type, detector reading or observation, pressure, operating state, access needs, priority, repair owner, date found, date repaired, and verification status. A consistent record structure turns a one-time air leak survey into usable maintenance data.

How to Estimate Wasted Energy and Cost

A screening estimate should connect the leak size or measured flow to operating hours, compressor performance, electricity price, and system pressure. A general framework is:

Annual cost estimate = estimated leak flow × equivalent compressor energy rate × operating hours × electricity price.

Flow estimates may come from calibrated ultrasonic instruments, manufacturer charts, controlled pressure tests, or system metering. The equivalent compressor energy rate should reflect the relevant compressor operating condition rather than an assumed universal value. Where multiple compressors or control modes are involved, use data that represents how the plant actually responds to demand.

Uncertainty can come from pressure variation, multiple compressors, changing production demand, dryer and treatment loads, cycling controls, and inaccurate operating-hour assumptions. A leak that appears during a short survey may not operate continuously, while a production machine may create demand that is incorrectly attributed to leakage.

Use screening estimates to rank repairs, not to claim guaranteed savings. Verified savings require a defined baseline, comparable operating conditions, an adequate observation period, and documentation of production, compressor-control, pressure, and equipment changes. Keeping those categories separate improves the credibility of energy reporting.

How to Prioritize Leak Repairs

The loudest leak is not always the highest-value repair. A smaller leak on a critical production machine may present a greater quality or downtime risk, while a larger leak in an accessible, noncritical area may be repaired quickly. Prioritization should combine estimated annual cost with operational consequences and repair practicality.

• Urgent: Address promptly when the condition threatens personnel safety, product quality, critical pressure, equipment integrity, or an imminent production interruption.
• High: Repair soon when the estimated cost is material, the leak is continuously exposed to operating pressure, or the repair is straightforward and can be completed with limited disruption.
• Planned: Schedule during a maintenance window when isolation, replacement parts, elevated access, or production coordination is required.
• Monitor: Track and recheck when the signal is small, uncertain, intermittent, or temporarily inaccessible, while setting a defined review date rather than leaving it open indefinitely.

Use different work paths for quick repairs, planned shutdown work, component replacement, and recurring root-cause fixes. A repair that repeatedly fails may need changes to hose routing, vibration control, installation practice, component selection, or protection from abrasion and thermal cycling.

Repair Practices That Prevent Repeat Leaks

Replace damaged hoses and tubing instead of treating them as permanent repair points. Correct poor fitting alignment and support flexible connections so they are not loaded by bending, vibration, or tensile force. Tighten or reseal connections according to manufacturer guidance, and use compatible sealing materials and installation methods.

Replace failed valves, regulators, filters, and automatic drains when cleaning or adjustment will not restore reliable operation. Eliminate unnecessary open-air uses where a suitable mechanical, electric, or low-pressure alternative is available. Remove abandoned branches or isolate them correctly if they no longer serve a process.

Never use hands to locate a suspected leak. Escaping air can injure skin or drive contaminants into tissue. Do not over-tighten fittings, apply unsuitable sealants, or repair pressurized equipment without proper isolation. Follow lockout/tagout and site procedures before disassembly.

Increasing system pressure is not a substitute for leak repair. Higher pressure can increase leakage flow, energy use, and component stress while masking the underlying condition. Pressure changes should be based on process requirements and verified system design, not used as a default response to unstable performance.

How to Verify Repairs and Savings

Repair verification and financial savings verification are different activities. Repair verification confirms that the original leak signature is gone. Financial savings verification determines whether system energy use changed as expected after accounting for operating conditions.

After a repair, repeat the same detection route where practical. Confirm that the original signal has disappeared, inspect nearby components for secondary leaks, and record the repair date and work performed. If the original condition cannot be isolated or measured individually, document that limitation and verify the repair at the component or branch level.

For system-level verification, compare compressor run time, loaded and unloaded behavior, flow, pressure stability, and production-normalized energy data before and after repairs. Use comparable production schedules, product mix, operating pressures, ambient conditions, and compressor sequencing where possible. Allow an adequate observation period rather than relying on a single shift.

Document changes that could affect the comparison, including added production, removed equipment, altered pressure settings, compressor-control changes, maintenance on dryers, and seasonal operating differences. A credible savings record explains both what changed and what could not be measured with confidence.

Turn Leak Detection Into a Maintenance Program

Survey frequency should reflect leak history, operating conditions, production criticality, staff availability, and the consequences of pressure loss. A facility with recurring hose damage or frequent temporary connections may need more frequent checks than a stable, well-controlled system. The appropriate schedule should be based on observed conditions rather than a universal interval.

Assign clear ownership. Maintenance may own detection and repairs, operations may identify abnormal pressure or equipment behavior, engineering may address system design and recurring causes, and energy management may coordinate cost estimates and savings verification. Shared ownership prevents leak work from becoming an unassigned list.

A dashboard or work-order system can track open leaks, overdue repairs, repeat failures, estimated cost, verified repairs, and overall system condition. Review trends by area, component type, shift, and failure mode. Survey results can reveal root causes such as vibration, poor installation, hose abrasion, thermal cycling, contamination, unsupported tubing, or unsuitable components.

Common Mistakes to Avoid

• Finding leaks but failing to create maintenance work orders with owners and due dates.
• Reporting detector readings as exact energy savings without a documented conversion method.
• Surveying only during quiet periods or only during production.
• Ignoring automatic drains, end-use devices, temporary connections, and inappropriate open-air uses.
• Rechecking repairs without documenting baseline conditions or the original leak location.
• Treating a pressure increase as an efficiency improvement.
• Failing to coordinate repairs with production, access, isolation, and safety procedures.

Frequently Asked Questions

What is the most effective method for finding compressed-air leaks in a noisy factory?

Ultrasonic detection is often effective because it focuses on high-frequency sound that can be distinguished from much of the surrounding plant noise. The technician should still scan methodically, adjust sensitivity, compare nearby components, and confirm the source before recording a leak.

Can ultrasonic detection measure the exact amount of air being lost?

Not by itself in every application. Ultrasonic instruments primarily locate and indicate leak signals. Exact or more defensible flow estimates require calibrated equipment, suitable conversion data, controlled pressure testing, or system metering.

How often should an industrial facility perform a compressed-air leak survey?

Set the frequency according to leak history, production criticality, operating conditions, and available resources. Use repeat survey results and overdue repair trends to adjust the schedule rather than applying the same interval to every facility.

How can a plant calculate the payback of a leak repair?

Estimate the annual cost of the leak using measured or screened flow, compressor energy rate, operating hours, and electricity price. Divide the repair cost by the expected annual cost reduction, while clearly identifying uncertainty and distinguishing screening estimates from verified savings.

What should be documented after a leak is repaired?

Record the asset ID, location, repair date, work performed, parts used, isolation or production conditions, post-repair detector result, nearby conditions, and verification status. Update the work order and equipment map when the repair changes the asset or its location.

Conclusion

Effective industrial compressed-air leak detection is a management cycle: survey, quantify, prioritize, repair, verify, and repeat. The strongest programs connect field observations to operating conditions, realistic cost estimates, accountable work orders, safe repair practices, and documented follow-up.

Begin with a mapped baseline survey and a consistent repair-verification process. Over time, the resulting data can improve compressed-air system maintenance, support factory energy efficiency decisions, and expose recurring equipment or installation problems that a single inspection would not reveal.