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Compressed air leaks are very common within compressed air systems and if left unattended, can leave you wasting a lot of energy. This page will present to you all the relevant information on compressed air leaks, how to find them, and how to fix them!

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Compressed Air Leaks

According to the U.S. Department of Energy, if compressed air leaks are left unaddressed they will waste as much as 20-30% of an air compressor’s output! It’s so easy to ignore these leaks, but it’s evident how crucial it is to identify them and fix them as soon as possible.

Air compressor leaks are a critical source of energy wastage, they significantly reduce system efficiency and productivity – nobody wants this right?! It is very important that you check the air compressor system regularly so that you can avoid potentially huge maintenance costs.

Leaks contribute to operating losses by causing a drop in system pressure, resulting in less efficient air tools and adversely affecting production. In addition to this, by forcing the equipment to cycle more frequently, leaks shorten the life of almost all system equipment.

Increased running time will also lead to additional maintenance requirements and increased unscheduled downtime.

If you suspect that you have a compressed air leak, make sure you do something about it right away!

Locating Compressed Air Leaks

Leaks can be found in almost any part of a compressed air system, the most common problem areas:

  • Baghouses
  • Condensate traps
  • Couplings
  • Cylinder rod packing
  • Disconnects
  • Filters
  • Fittings
  • Flanges
  • Hoses
  • Lubricators
  • Point-of-use devices
  • Pipe joints
  • Pressure regulators
  • Shut-off valves
  • Thread sealants

If you suspect your compressed air system has an air leak, these are the first places you should check!

How to Detect Compressed Air Leaks

To detect compressed air leaks, you should use any of the following 3 most common methods:

  1. Listening and feeling
  2. Soapy water
  3. Ultrasonic leak detection

Now let’s look at each method in greater detail!

Listening and Feeling

A simple method for checking air leaks is to listen for them and then feel around the compressed air system for leaking air. This method, however, is restricted to larger leaks that are located in easily-accessible locations.

Note: it may be difficult to hear the leaks over the loudness of the compressor. Therefore, this method is quite limited.

Soapy Water

Apply soapy water using a paintbrush to areas where a leak is suspected. Bubbles will form if there is a leak in this location.

Though this is very reliable, this method can be rather time-consuming. It requires direct access and so leaks in hard-to-reach areas of the system will go undetected.

If leaks are found, it will not indicate which ones are losing the most air, so it’ll be impossible to prioritize the repairs.

Ultrasonic Leak Detection

The best method for detecting compressed air leaks is this ultrasonic leak detection, which has quickly become a standard method in the industry.

The portable devices typically consist of a directional microphone, amplifier, and audio filters that allow you to utilize earphones or visual indicators to help the user detect the air leaks.

They basically detect the high frequency “hissing” sound that is created when compressed air leaks into the atmosphere which is sometimes so small that it is inaudible to the human ear.

This allows you to pinpoint the tiniest of leaks even in noisy environments due to the directional and localized sound.

Compared to the other two methods, ultrasonic leak detection doesn’t require physical access to the leaks. On top of this, they can estimate the volume of air leakage so that you can prioritize your repairs.

Here’s an example of an ultrasonic acoustic detector readily available on Amazon!

How to Fix Leaks

Leaks occur more often than not at joints and connections at end-use applications. Stopping these leaks can be as simple as tightening a connection or as complex as replacing faulting equipment such as couplings, fittings, hoses, pipe sections, joints and drains.

In many cases, bad or improperly applied thread sealant will result in leaks. Ensure you install high-quality fittings, disconnects, hoses, tubing, etc, and install them properly with appropriate thread sealant.

Non-operating equipment can also be where you are leaking compressed air. If this is the case, equipment no longer in use should be isolated with a valve in the distribution system.

Another way to fix or at least reduce the leaks is to lower the air pressure of the system. The lower the pressure differential across an orifice or leak, the lower the rate of flow and therefore reduced leakage rates. Stabalizing the system header pressure at its lowest practical range will minimize the leakage rate for the system!

Leak Prevention Program

It’s so important to have a good leak prevention program in place. This will include:

  • identification (tagging each leak with a unique ID number or code)
  • tracking (record information of each leak)
  • repair
  • verification
  • employee involvement (if necessary)

A leak prevention program should be part of the overall program aimed at improving the performance of compressed air systems. Once the leaks are found and repaired, the system should be re-evaluated.

A good leak prevention program is very important in maintaining the efficiency, reliability, stability, and cost effectiveness of any compressed air system.

Estimating Leak Rate

Identifying and quantifying the leak load is very important when considering the entire effect of leaks on the compressed air system. To do so, use a bleed-down test to quantify the leak rate of the system, or alternatively, estimate the leak rate if you have a pressure gauge downstream on the receiver.

This method requires an estimate of total system volume, including downstream secondary air receivers, air mains, and piping (V). Then you can start the compressor and bring it to the normal operating pressure (P1) before turning it off.

Measure the time (T) it takes for the system to then drop to the lower pressure (P2) – which should be about half the operating pressure.

This method can then be utilized by using the following formula:

Leakage (CFM free air) = [V x (P1-P2)/(Tx14.7)] x 1.25

Where:

  • V = volume in cubic feet
  • P1 = pressure 1 in psi
  • P2 = pressure 2 in psi
  • T = time in minutes

The 1.25 multiplier at the end of the equation corrects the leakage to normal system pressure, allowing for reduced leakage with falling system pressure to 50% of the initial reading.

A leakage of greater than 10% indicates a more serious problem and leaves significant room for improvement. Carry these tests out once a month as part of the regular leak detection/prevention program.

FAQs (Frequently Asked Questions)

How do you fix a compressed air leak?

Fixing compressed air leaks can be as simple as tightening connections or as complex as replacing faulty parts in the compressed air system like couplings, fittings, hoses or drains. Improperly applied thread sealant may well be the cause of the leak, so ensure it is applied properly.

How do you calculate the cost of compressed air leaks?

A general estimation for the cost of a compressed air leak is that 1 CFM of air costs around $35 per shift annually (this is assuming an average energy cost of about $0.08/kW). If you run multiple shifts, multiply that number by 2 or 3; if your plant runs 24/7/365, multiply it by 4.2.

How do you find air leaks?

To find air leaks, you should either listen and feel around the compressed air system, apply soapy water to places you suspect are leaking and look for bubbles and finally, use an ultrasonic leak detection device.

Useful Pages on Air Compressor Leaks


If you have any questions regarding compressed air leaks, please leave a comment below, with a photo if applicable, so that someone can help you!