For industrial plants and facilities, compressed air, gas and vacuum systems are a vital source of converted energy. Easier than other resources such as electricity, compressors are everywhere in today’s factories. They run machines, tools, robotics, lasers, product handling systems, and much more.
Yet many compressed air, gas and vacuum systems are compromised by wear and poor maintenance practices, which contribute to the greatest waste of all—the ever-present leaks. These leaks can be hidden behind machines, at connection points, overhead in fixed pipes, or in cracked pipes or worn hoses. The waste adds up quickly and can even lead to downtime.
The High Cost of Wasted Compressed Air
According to industry statistics, a single 1/8” (3mm) leak in a compressed air line can cost upwards of $2,500 USD a year. Industry estimates also recognize a plant that has not been well maintained can waste 20% of its total compressed air production capacity through leaks. The New Zealand government, as part of its Target Sustainability project, has estimated that system leaks can account for 30 to 50% of a compressed air system’s capacity. Quick detection of compressed air, gas and vacuum leaks is a single factor in finding hidden profits. Air leaks can also lead to capital expenses, rework, downtime or quality issues and increased maintenance costs.
To make up the pressure loss due to leaks, operators often overcompensate by buying a larger compressor than is needed, which requires significant capital costs along with increasing energy costs. System leaks can also cause air dependent equipment to fail due to low system pressure. That can lead to production delays, unplanned downtime, quality issues, decreased service life, and increased maintenance due to unnecessary cycling of compressors.
The maintenance manager of one United States manufacturer, for instance, says low pressure in one of their air torqueing tools can potentially lead to product defects. “Mis-torqued units, either under torqued or over torqued, can lead to recalls. That also leads to more man hours put into something that should have been a very standard process,” he says. “It’s money out the door in lost profits and lost units. In the worst-case scenario we also wind up with lost demand because we weren't able to deliver.”
It’s no wonder that utilities, industry, and government all target compressed air systems as a potential source of cost savings. Leaks lead to waste. Correcting those leaks can save the operator money and prevent the utility from having to build additional capacity into their system.
How Much Air Are You Wasting?
The first step in controlling leaks in compressed air, gas and vacuum systems is to estimate your leak load. Some leakage (less than 10 %) is to be expected. Anything beyond that is considered wasteful. The first step is to determine your current leak load so you can use that as a benchmark to compare improvements against.
Really not interested in doing the math? See how the Fluke Acoustic Cameras with LeakQ Mode let you quantify the size of leaks in your compressed air system. Watch the video.
The best method for estimating leak load is based on your control system. If you have a system with start/stop controls, simply start your compressor when there is no demand on the system—after hours or off shift. Then take several readings of compressor cycles to determine the average time to unload the loaded system. With no equipment running, the unloading of the system is due to leaks.
Leakage (%) = (T x 100) ÷ (T + t)T = onload time (minutes), t = offload time (minutes)
To estimate leak load in systems with more complex control strategies, place a pressure gauge downstream from the volume (V, in cubic feet), including all secondary receivers, mains, and piping. With no demand on the system, except leakage, bring the system up to its normal operating pressure (P1, in psig). Select a second pressure (P2, about half the value of P1) and measure the time (T, in minutes) it takes for the system to drop to P2.
Leakage (cfm free air) = [(V x ( P1 – P2) ÷ (T x 14.7)] x 1.25
The 1.25 multiplier corrects leakage to normal system pressure, thereby accounting for reduced leakage with decreasing system pressure.
Efficiently fixing and repairing leaks can lead to substantial cost reduction for air-dependent businesses. Companies are not only able to save on energy use by repairing leaks but can also improve production levels and extend equipment life.
Finding and Fixing Compressor System Leaks
Many plants and facilities do not have a leak detection program. Finding and fixing leaks wasn’t easy. Today, leak detection equipment such as the Fluke ii905 Acoustic Camera and the Fluke ii915 Acoustic Camera, both with LeakQ Mode, make the process to find, quantify, and verify fixes easy as ever. Quantifying the amount of waste and determining the cost used to require energy specialists or consultants who would use energy analyzers and loggers to audit your air systems. With Fluke Acoustic Camera technology, this capability is back with the maintenance teams for faster response and more proactive monitoring.
Ready to see how to prioritize compressor system leaks with LeakQ Mode? Read this article on How to Prioritize Compressed Air System Leaks for Repair.