Save Money by Detecting and Repairing Air Leaks in Compressed Air Systems

Compressed air systems are essential for running machinery and other production operations, in a multitude of industries. Ironically, the cost and electrical power required to own and operate a compressed air system can be highly expensive, and most users consciously recognize this. However, despite this knowledge, they allow air leaks to quietly eat away at the companies’ bottom line profits, while trying to cut expenditure in other critical areas of their maintenance operation to balance budgets.

Does this sound familiar?

In this detailed guide, we delve into the financial impact of compressed air leaks, investigate the unnecessary wear and tear on your generating equipment, efficient detection methods, and provide guidance on developing a proactive repair program to save both energy and money.

Industrial manufacturers and other production or service establishments disregarded compressed air leaks in their processes for many years. However, the industry standard has changed drastically, and now, not only does conserving this resource help save money, but it can also boost machinery performance while enhancing product quality. Compressed air is one of the most expensive energy sources in an industrial facility, and according to the Department of Energy (DOE), on average, compressed air systems that are not regularly maintained after installation could be losing 20 to 30% of compressed air in leaks.

In short, air leaks might be costing your business considerable amounts of money through unnecessary electrical costs, created by “easy to combat” compressed air leaks.

Unfortunately, compressed air leaks are very common in almost every system, so the question is, how do you detect these air leaks? The first option is relatively simple; whenever you are walking through your compressor room, and its associated distribution pipework network, you can listen to identify potential leaks. Listen for a hissing sound as you pass the compressor and the distribution piping, all the way to points of use. One of our clients, shared the cost savings obtained from identifying a leak and repairing it, with their staff. They offered the staff an incentive bonus, in the way of a gift card, and in return for advising and reporting the leak to their team leaders. 16 machine operators reported leaks at their machine, and the net saving was $4,950.00 in conserved hydro, at a cost of $400 in gift cards and $1,100.00 in repair time and materials.

Audible detection isn't always the ideal solution, particularly when the workplace is a loud factory, plant, or body shop. Large piping networks, with elevated pipe runs are also difficult to navigate audibly too.

An ultrasonic acoustic leak detector gun is one of the most trustworthy instruments for finding any air compressor or airline leakage. These handheld devices are a lightweight gun, which typically include visual indicator gauges, headphones, amplifiers, and audio filters. Simply point and shoot the handheld device at the pipework and pull the trigger to capture the leaks dB(A) level, and the software, which accompanies the gun, will convert the dB(A) into cfm loss and subsequently the dollars and cents being exhausted into the atmosphere. Tagging the leak, with a numeric log, will make the repair and elimination of leaks, an easier task. Once the leak is repaired, or fixed, the tag can be removed, and the savings will be instant.

The high frequency discharge noises, created by a pipe leak, are easily detectable using an ultrasonic detector, however walking the piping network, and gazing into roof and ceiling spaces can be uncomfortable on the neck, and tiresome. These devices work well in loud establishments.

The Air Solutions Canada Inc team has invested wisely in our leak detection technology, and nowadays we utilise the Fluke ii900 industrial acoustic imaging device. This compact handheld reader provides a broad spectrum “point and shoot” process from a tablet shaped device. The picture captured, by the device operator, is a crystal-clear image of the production, or facility location showing piping, and pinpointing all leaks in that area, together with the statistics of air loss, energy consumption and the costs associated. No need for headphones, no need to stare for hours at the ceiling space. It’s very slick and user friendly, and our detection audits are completed in less time, at a lower cost. The Fluke ii900 captures approximately 15% more leaks than the ultrasonic gun device.

Reasons you should identify and repair compressed air leaks

If you choose to ignore the negative effects that air leaks may have on your yearly energy costs, it’s important to note that leaks will still reduce operating efficiency, and lead to lost productivity because of the system's unavoidable decline in air pressure. This might lead to shorter equipment service lifespans and less effective use of processes, air tools, spray paint finishes, cylinders, valves, and “blow offs” which use compressed air.

If we dig a little deeper, the following points should convince you to identify, and repair compressed air leaks for the following reasons:

Energy loss and increased hydro power bills.

We recommend that you perform your own “Litmus test” to confirm whether performing a leak detection study is a worthwhile investment, of time and money, at your location.

The calculation is easy and will help you to estimate how much energy your system wastes annually.

Follow this simple 5-step air leakage calculation guide.

1. Hazzard a guess, as to the number of leaks you think are apparent at your facility.
2. Use the table above to reference the orifice diameter, and the power required to feed this leak, (columns #1, 2 and 4).
3. Add the combined kW totals together to establish the amount of power required to compress the air you feel is being lost at your plant.
4. Multiply this kW total by the energy cost shown on your Hydro bill, (typically this is approximately $0.13, on average, in Ontario Canada).
5. Multiply this figure by the amount of production hours that the air compressor(s) run for in a year, and this will confirm whether investing $1,700.00 to perform the Fluke ii900 thermal imaging detection study is a worthwhile investment.

As a hypothetical exercise, and example, let’s say that you have 15 x 1/16” leaks, 8 x 1/8”, 2 x 3/8”, and zero ¾”. Your total power loss will be 45.9kW. If your facility operates 8 hours per day x 5 days a week, x 52 weeks, the air compressor annual run time will be 2,080. If energy costs are $0.13kW/hr, the loss equates to a staggering $12,411.36.

Now that we have your attention let’s look at some other facts.

Reduced equipment lifespan:

In our fabricated case study above, the compressors will cycle more frequently, as a result of leaks, in order to sustain system pressure and cfm consumption.
Rapid cycling the compressor will shorten the service life expectancy of the inlet valve, minimum pressure valve and oil stop valve. Oil carryover can also become an unwanted problem too.

Additional impacts:

1. Air leaks not only shorten the lifespan of the valving arrangement in your air compressors, but they will also increase the ambient noise levels at your workplace. The National Institute for Occupational Safety and Health (NIOSH) has recommended that all worker exposures to noise should be controlled below a level equivalent to 85 dBA for a maximum of eight hours to minimize occupational noise induced hearing loss.
2. Leaks will create drops in system air pressure, which can have a significant effect on your plant's production by making tools run inefficiently and resulting in a production environment that is generally less productive.
3. In many production facilities we visit the generating pressure, that the air compressor is set at, is often superficial and considerably higher than it needs to be. Pressures are raised, inside the compressor room, in an attempt to overcome the systemic “low system pressure” issue, plant wide. This practice is only a Band Aid solution to a much bigger problem – which lies in the shape and form of leaks, a lack of storage, or poorly designed pipework distribution networks. In an extreme case, it can be all three!Reducing the compressed air generating pressure will net huge energy savings for you and your operation. For every 2psig generating system pressure reduction, 1% energy savings are achieved.Imagine lowering the generating pressure by 10psig and saving 5% in annual kW energy savings.
4. Augmented, and superficial generating pressure will also increase the amount of compressed air being lost through leaks. With air leaks and increased pressure, it is almost a 1:1 ratio. In fact, a pressure increase from 100 psig to 125 psig leads to an additional 22 cfm in compressed air loss, on average from any given leak. Leaks will be decreased by lowering the compressed air system's demand air pressure, because a reduced flow rate will create a lower pressure differential across an orifice or leak, which in turn results in a lower rate of leakage.

Finding compressed air leaks

The most common areas in a compressed air system where our team locate leaks is at connections and junctions. Many leaks can be stopped, with ease, by tightening a fitting, a hose clamp, or connection.

More complicated leaks may require the replacement of a leaking gasket, or seal, a broken coupling, fittings, pipe sections, hoses, drains, and traps. This is where the investment and foresight of installing shut off, isolation valves pay dividends. Without local isolation valving, a planned shut down will be necessary, in order to address some leaks. We will “circle back” to this momentarily.

Leaks are frequently the result of poorly applied, or defective thread sealant, or Teflon tape, and these can be resolved by installing equipment correctly and using the right thread sealant.

Often, non-operating equipment might be another source of leakage, and if machinery is being “moth balled”, decommissioned, or retired, the addition of a distribution system shut off valve should be used to isolate out-of-service equipment.

Assessing the general level of compressed air flow during nonproduction periods, such as a Sunday perhaps, can be a good way to gauge the potential of reducing leakage. If your plant production is shut down during specific periods, or production cycles, and your system is fortunate enough to have flowmeters, you can record the flow-meter readings over the production outages to obtain an approximate estimate of your potential leakage flow. A recent case study flow profile in a plastic components’ facility revealed that the plant consumed as much as 50cfm on weekends, despite there being zero production occurring. To generate 50 cfm, we would require a 10hp, (7.5kW) air compressor.

If we roughly approximate a 48-hour weekend period, x 52 weeks, x 7.5kW, x $0.13c = $2,433.60.

Let’s summarize the facts, and devise a plan to address the simple picking of this low hanging fruit. Supported by various studies, and data, we recognize, and understand the seriousness of the situation:

• It is estimated that more than 50 percent of all compressed air systems have energy efficiency problems requiring attention immediately. (uesystems.com)
• Air compressors produce massive amounts of heat, with approximately 10% to 15% of the energy remaining being used for compressed air powered applications (plantservices.com).
• Around 30% of all industrial compressed air is usually lost to leaks, resulting in huge losses in Hydro (uesystems.com).
• Studies have shown that an average of 25% of all compressed air produced is lost because of system leakage before it ever gets to the final end use (plantservices.com).
• In extreme cases, more than 80% of the air that the compressors produce is lost through system leakage (plantservices.com).

So how do we improve what we are doing currently?

Creating a plan of attack for your compressed air leaks

1. We cannot improve what we don't measure
   • Perform an audible walk through of your system.
   • Invite, and engage the machine operators and production staff to identify their own leaks.
   • Follow the simple 5 step estimation guide on page # 2 of this Blog.
   • Employ a professional to perform a leak detection audit.
   • Install flow meters.
   • Tag the leaks.
2. Decide how often you want to detect leaks inside your facility. “Many hands, make light work”, so engage your colleagues and share the table below with them.
3. Ensure that all of the tubing, hoses, disconnects, and fittings are of the highest calibre and confirm that the thread sealant is applied correctly.
4. All non-operating, decommissioned equipment should be isolated using an isolation valve.
5. Attempt to lower the system's air pressure by 1, or 2 psig each week. Eventually someone in production will advise you that they are experiencing pressure issues, and this will signal that you have reached an acceptable generating pressure.
   

   Ask yourself the question; “Why generate compressed air at 125psig, when the equipment pressure regulators at points of use are wound down to 80psig?”

6. After leaks are fixed, check the compressor control system again, and make the necessary adjustments required to sustain the achievements. By implementing this action, the energy savings will be maximized.
7. Celebrate the success and savings achieved with your team.
8. Create a maintenance reminder to rinse and repeat the process, tomorrow, next week, next month, quarterly, semi-annually, or once per year.

If your facility enjoys a plant shut down, (Easter, Summer, Thanksgiving, or at Xmas), we strongly recommend that the detection occurs a few weeks before, to allow you to order and receive the parts and materials required to repair and fix the leaks which reside downstream of pipes that do not have isolation valves.

Unfortunately, leak identification and repair are never one-time events. The compressed air system will likely require more maintenance as it matures, or changes over time. Leak detection and repairs must be viewed as a continuous program if you want long-term outcomes. The simplest method to make sure leak detection is remembered is to create a program for continuous improvement. You might want to talk to your compressed air service provider about incorporating leak detection into your preventative maintenance schedule as part of this plan. Energy savings from a continuous leak detection audit and repair program will quickly provide a rapid ROI. In addition, you will benefit from improved manufacturing equipment performance and less downtime.

In conclusion, even though they are frequently encountered, compressed air leaks are simple to find and address. It is imperative to conduct routine leak detection and repairs in order to avoid mounting expenses. Please contact us if you have any questions about leaks or general air compressors.