Are You Letting Money Escape Into Thin Air?
If your compressed air system has unrepaired leaks, the answer is yes. Leaks in your compressed air system may be increasing your compressed air energy bills by more than 30%. Since compressed air is usually one of the largest energy expenses for a manufacturer using air-powered equipment, that represents a significant opportunity for energy savings.
Fortunately, finding and fixing compressed air leaks is a relatively simple and cost-effective process. Thanks to energy incentives provided by most energy suppliers—including ComEd in Northern Illinois—you may even be able to get compressed air leaks fixed for free.
The Average Cost of a Compressed Air Leak
A good rule of thumb when calculating the cost of a compressed air leak is that one CFM* of air costs about $35 per shift annually (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 big is a 1 CFM leak? Not very. If you can hear the leak while you’re walking by, it’s likely leaking at least 1 CFM.
Most plants have multiple leaks throughout their compressed air systems, most of them too small to be detected by human ears. These can quickly add up to thousands of dollars in energy losses each year. In fact, on average, 35% of the energy costs associated with compressed air can be considered wasted energy. A large part of that waste is usually due to compressed air leaks. (The other major cause of wasted energy is system over-pressurization; see if you could save energy by reducing the PSI of your system.)
Total Costs of Compressed Air
For the average manufacturer, 20-30% of total energy consumption is compressed air; 35% of that energy is wasted due to air leaks and other inefficiencies.
Consider the following scenarios:
Calculating the Cost of Wasted Air for Your Compressed Air System
You can easily estimate the cost of air leaks for your compressed air system using the worksheet below.
Let’s look at an example for a 100 HP air compressor running a single shift (about 2500 hours per year):
And for a 100 HP air compressor running 24/7/365:
Aire Tip: When calculating the number of hours your air compressor runs annually, consider that you are probably powering it up in advance of a shift and powering down after the shift has ended. E.g., your compressor may be running 9+ hours to power an 8-hour work shift.
How to Locate Compressed Air Leaks
Some compressed air leaks are large enough to hear. These are your largest source of CFM loss and should be found and repaired immediately. The best way to find these is to walk around your facility when it is quiet but the compressor is still running, perhaps immediately after a shift before you power your compressor down. (if you are running production lines 24/7, just try to find the quietest part of the day, or take advantage of any temporary shutdowns of production equipment for standard maintenance.) Once you locate a leak by sound, you may be able to confirm its location by feeling for air movement.
Most compressed air leaks, however, are much too small to detect by listening or feeling. Tiny leaks still create a sound, but the frequency is above the threshold of human hearing. These pinpoint leaks are still important to find and fix. The average facility has at least 20-30 of these leaks throughout the compressed air system, and larger facilities may have dozens. Together, they add up to significant CFM loss.
These smaller leaks can be found using specialized equipment such as an ultrasonic leak detector. This is an easy and non-invasive way to detect tiny leaks in the compressed air system. The ultrasonic detector uses the high-frequency sound emitted by small leaks to pinpoint their location. Pinprick leaks emit sound in a range of about 40 kHz, about twice the upper frequency detectable by humans. Ultrasonic detectors listen for noise in this range. As the operator moves around the facility, the detector will indicate whether they are getting closer to or farther from the leak by determining whether the sound is getting louder or softer. In this way, the detector leads the operator right to the source of the leak, much like the children’s game of “colder/warmer.”
Common Culprits for Compressed Air Leaks
Compressed air leaks can be found anywhere in the system. Older compressed air piping often develops leaks at joins and welds over time. Read how we helped Aurora Bearing save $4,500 per year through free leak repair.
Many leaks can be found in what is known as the “dirty thirty”: the last 30 feet of pipes, hoses and connectors that hook a piece of equipment into the compressed air system. Quick couplers, in particular, are prone to develop leaks over time as rubber seals degrade. Other common sources of compressed air leaks include a slit or leaky hoses, worn insta-tube fittings and loose threaded joints. Most of these leaks are easy and inexpensive to repair. Your in-house maintenance team may be able to find and repair many of these leaks on an ongoing basis for your facility.
Is It Worth It to Fix Compressed Air Leaks?
Sometimes, manufacturers wonder if it is worth it to fix compressed air leaks. In most cases, the answer is yes—especially since you can often have leak repair done for free (as we’ll explain below).
Deciding whether or not to fix compressed air leaks comes down to a matter of ROI. You should ask:
- How much is this leak costing me? You may be able to estimate this for a single noticeable leak based on the size of the leak (and the resulting CFM loss), using the rule of thumb that every 1 CFM lost costs $35/hour of operation. If you are trying to estimate the total energy loss due to leaks and other inefficiencies in your facility, use the worksheet above.
- How much will the leak cost to repair? You may be able to repair many of them for free under incentive programs provided by your energy company. However, some leaks may cost more to repair than your energy company will cover, due to their size or the overall difficulty of the repair. Your compressed air provider can give you an estimate of the repair costs over and above what your energy company will cover.
- What are the other costs associated with leak repair? If repairing the leak will require you to shut down production lines, for example, you should include the cost of the shutdown in your calculations.
In most cases, the answer will still be yes, especially for leaks that are large enough for you to notice. If you’re not sure, Fluid-Aire Dynamics can help you run the calculations to determine whether leak repair makes sense for your facility.
Aire Tip: Don’t forget to include hidden costs, like lost productivity, in calculating the ROI for leak repair.
Should You Fix Compressed Air Leaks During a Slowdown?
Some manufacturers wonder whether leak repair should be conducted during a slowdown, such as the slowdowns experienced by many plants in the spring of 2020 due to COVID-19. There are two schools of thought on this. Some compressed air providers claim that companies should not fix leaks during a slowdown, because operating at reduced load for extended times can damage your air compressor. Fixing leaks when the system is already operating at under-capacity, the thinking goes, will put additional stress on your system by further reducing the load.
There is some truth to this: when air compressors (in particular fixed-speed rotary screw air compressors) operate at reduced capacity, they will begin short-cycling, which can damage the motor. They are also prone to moisture build-up because the system does not run long enough and hot enough to burn off excess moisture.
However, we believe that a slowdown can provide a great opportunity to fix leaks. Here’s why: during a slowdown, when production lines are already slowed or stopped, it’s easier for technicians to get in and fix leaks without disrupting operations. And there are many other ways to compensate for reduced demand on the compressed air system, such as artificially increasing demand by venting air lines on a regular basis, swapping in a lower HP compressor (such as a backup system) or adjusting compressor controls. Fixing leaks while production lines are slow will ensure that your system will be operating at maximum efficiency when things pick up again.
Get Compressed Air Leaks Fixed—For Free
So here’s what you really want to know—how can you get compressed air leaks fixed for free? If you’re a ComEd customer in Northern Illinois, you may qualify for the Fix-It-Now Leak Repair Program.
Here’s how it works:
- Fluid-Aire Dynamics comes out and located leaks in your facility using an ultrasonic detector.
- Wherever possible, we’ll fix the leaks that we find in the same visit. If we run across a leak that can’t be easily repaired on the spot, we’ll tag it for later repair.
- We send the bill to ComEd, up to $120/leak ($20 for detection and $100 for repair). If an individual leak will cost more than that to repair, we’ll tag it and give you an estimate for the additional repair costs.
ComEd pays for leak repair as part of their energy incentive program to reduce the overall demand on the grid. Not a ComEd customer? Most energy providers have similar incentive programs.
Aire Tip: Look for energy incentive program fees on your utility bill under “taxes and fees.” Contact your energy provider to see if you qualify.
Need help calculating the ROI of leak repair? Contact us for help with energy incentives and compressed air system leak repair.
*Cubic Feet per Minute, the standard measurement of the velocity of air flowing through a system. The volume of air your air compressor is capable of producing in a given amount of time is usually measured in CFMs; a compressor rated for 50 CFMs produces 50 cubic feet of air every minute at max capacity.
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