Unlike power supply, compressed air is generated onsite by the user and often the compressed air system is designed without accounting for measures such as air treatment, proper piping material selection, dimensioning the air distribution system correctly and spare capacity.
The result is a compressed air system that is very expensive to operate and does not help the user achieve productivity that the system is designed for.
Amongst all the above points mentioned, proper air treatment and using the correct material for piping, gain significance as these two factors result in a major cost impact to the user by generating leaks in the air distribution system. Compromising on either can lead to implications on cost and productivity, with untimely compressed air leak.
Important factors to bear in mind as to why air leak happens are:
- As in general operating issues, most air leaks are caused by material failures, like missing welds, tubes, locks, end fittings threads etc, or other improper fittings.
- Worn-off systems, or improper operation can also lead to air leaks.
- Cheap, improper filters, regulators and lubricators (FRLs) also frequently cause air leaks. To prevent it from happening, it is suggested to choose a high-grade product range for your system set-up from Atlas Copco, the reliable supplier of high-quality air compressors.
Many detailed studies have revealed that an average of 25% of all compressed air produced is lost because of system leakage before it ever gets to the final user point. In some extreme cases, more than 80% of the air is lost through system leakage.
If poor system productivity isn’t a good enough reason to thoroughly check for air leaks , other factors that will press on its importance are reduced reliability, increased costs and the system’s unexpected shutdowns.
Why is the air leak detection test absolutely needed for your compressed air system? ?
To improve the efficiency of the compressed air system, it is advised to be proactive in matters of maintenance services. Conducting routine air leak tests will help cut down energy costs and downtime, increasing system’s overall performance. Air Leak Test of your installation verifies and measures the reason for compressed air wastage, which will help you arrest the expensive leaks.
That said, compressed air leak testing is also a clean way to check if your compressed air system meets leak-tight specifications.
Why does air leakage start?
How much does compressed air leaks cost?
A typical fully loaded well-maintained oil injected screw air compressor running at about 7 barg (100 psig) will consume between 15 – 20 kW to generate 100 cfm of compressed air.
If we consider the power tariff in UAE of an average 0.40 AED / kWhr, this would mean the cost of compressed air would be about AED 6 to AED 8 per hour of operation for every 100 cfm of constant compressed air flow.
If the compressor were to run 24x7, it would clock total running of 8,760 hours per year, this 100-cfm flow would cost between AED 52,560 to AED 70,080.00 per year just in cost of electricity. Obviously, there would also be further costs in maintaining the compressor because of this operating time.
If you need only 70 cfm of compressed air and your leakage level is 30% you would need to run the 100cfm compressor continuously nonstop resulting in a net loss of 30% which translates into AED 15,768.00 to AED 21,024.00 per year in leakages alone.
Summary of example:
| Working Pressure | Power | Flow | Power Rate | Working Hours per Annum |
Per Hour Electricity Cost | Annual Electricity Cost | Leakage | Leakage Cost per Annum |
| 7 barg | 20 kW | 100 cfm | 0.40 AED / kWhr | 8,760 | 8 AED | 70,080 AED | 30% | 21,024 AED |
Estimating the amount of air leakage
Does your compressor have stop/start control? We tell you a simple way to estimate the air leakage amount in your system. First, start your machine when the air-run end-use equipment remains off. After some measurements, you can figure out the average time taken load as well as unload the air compressor. Air leakages will make the compressor cycle off and on with a pressure drop.
To calculate total air leakage percentage, here is the formula:
Percentage of Leakage = [(T x 100)/(T + t)]
- T stands for on-load time (minutes)
- t stands for off-load time (minutes)
Compressor capacity lost (percentage) expresses the air leakage amount. In a well-functioning system, the compressed air leakage percentage should be below 10%. As for poorly maintained machines, losses can be anywhere between 20-30% of air power and capacity.
Does your system have any other control strategy? If the receiver’s downstream has a pressure gauge, then leakage could be estimated. For this method to work, you will have to estimate the total system volume, comprising secondary air receivers downstream, piping, and air mains. After the machine runs for a while, it is brought to the usual operating system. Then, you have to consider the time your system takes for a further pressure drop (P2).
Leakage of air (cfm) = (V x (P1-P2)/T x 14.7) x 1.25
- V = Cubic Feet
- P1 and P2 = psig
- T = Minutes
The significance of the 1.25 multiplier is that it can help correct the leakage to the usual system pressure. This then allows for minimized leakage with the dropping system pressure. Lastly, leakage of more than 10% shows the likelihood of the system to improve.
Conduct air leak test to avoid loss
Compressed air leaks are an invisible enemy of a user’s operations and end up adding to the costs of production. Before you start with a new investment project on compressed air system please speak to an Atlas Copco air audit consultant to conduct an air leak test and review the existing installation, which will help you arrest the expensive leaks. Once this is done, if the existing system is unable to meet the air demand, start your discussion with a professional Atlas Copco Sales Engineer your future requirements and expansion plans.
