The Hidden Costs of Compressed Air Leaks
By Bruce Gorelick And Alan Bandes
Most companies do their best to conserve energy. They realize that there is a high cost from the energy drain caused by the extra horsepower air compressors waste as they try to maintain pre-set air p...
Most companies do their best to conserve energy. They realize that there is a high cost from the energy drain caused by the extra horsepower air compressors waste as they try to maintain pre-set air pressures.
Likewise, most facilities realize how costly leaks in nitrogen, carbon dioxide and Freon systems can be. The focus of this article is not only about how leaks can negatively affect a compressed air/gas system as a whole, but also how leaks can have an impact on the environment and quite possibly the wellbeing of the personnel that have to work around these systems.
Air leaks can affect processes negatively. Control-and pressure-reducing valves are relied upon to control the manufacturing process. Precise control is critical for the product being made and for the indoor environments that plants seek to maintain.
Air for heating and ventilating systems needs to accurately control the heating and/or cooling process. For example, in biotech facilities, compressed air may control environments where the maintenance of humidity and temperature is a top priority. (If the degree of humidity in a controlled bio-genetic research facility goes awry, it can ruin months or years of research.)
Loose connections or splits in tubing can adversely affect proper control. Obviously, a ruptured diaphragm in a control valve cannot be properly controlled by a computer. Therefore, it should be apparent that facilities need to perform compressed air/gas leak audits on a regular basis, or make arrangements with a professional firm to have audits periodically performed.
In a compressed air and gas system, there are many critical components that require validation of proper operational capabilities. Non-critical system components likewise need to be scanned and tested for leakage. These include, but are not limited to, relief valves, solenoid valves, flange gaskets, thread connections, filter/regulator/lubricators (FRLs), welds, and threaded and quick-connection devices. At any given time they may not only be wasting energy but sacrificing proper process control.
Drain trap problems
Compressed air systems are depended upon to supply clean, dry air to equipment and components. Separators, receiver vessels, compressors and other components in a compressed air system depend on drain traps to automatically discharge condensed water from the system. When a drain trap fails in the closed position, it causes a back-up of condensate. The air fed to the system will contain water that can be detrimental to downstream equipment.
Rust, dirt and corrosion are additional consequences of not replacing failed drain traps in a timely fashion. Ignorance of plugged drain traps also contributes to other portions of a system becoming adversely affected.
If a drain valve fails in the open position, large quantities of energy are wasted. Since most drain traps are piped into discharge manifolds and then to waste drains, it is not generally visually apparent that they might have failed in the open position, therefore it is essential that regular ultrasonic tests be performed on these drain traps.
Valves, solenoids and other sensitive equipment can plug or stick in an open position and eventually fail. Many times the gaskets between banks of solenoids begin to leak when water has not been drained from the compressed air system. Sometimes oil in compressed air systems can cause O-ring or gasket failures.
If part of the system is outdoors and is subject to low temperatures, the air lines and the equipment to which it leads can freeze. The portions that freeze can crack and become permanently damaged.
A proper air leak audit should identify the components that are causing energy loss. The air/gas system is like a food chain, in that any one portion of the system that has failed will have an impact on the other parts.
Gas leaks: Costly and dangerous
Other gases are quite a bit more expensive than compressed air. The rule of thumb for contrasting a compressed air leak versus a nitrogen leak, for example, is that typically, nitrogen is 10 times more expensive than air. So who wants to live with even tiny nitrogen leaks? Living with many nitrogen leaks will, without doubt, take a big bite out of a company’s profits.
If the leaking gas is volatile, such as natural gas, identifying and repairing the leak becomes an urgent priority. In one example, a plant had 22 natural gas leaks in one section of piping near the ceiling. The gas line was feeding an oven that had ignition points every 10 ft along the length of the equipment. The potential safety hazard of these leaks far outweighed the actual cost of the leakages. Should an explosion have occurred, aside from the physical harm it could cause workers in the immediate area, it would have shut down the plant for quite some time.
In another example, a parts-manufacturing plant found it had a huge argon leak. The feed line that was carrying the gas to a welder had a hairline split. Although inert gases such as argon, helium and nitrogen are non-toxic and do not burn or explode, they can cause injury or death at high concentrations by displacing oxygen in the air. Should oxygen levels fall too low, individuals in the area could have lost consciousness.
These examples illustrate why it is crucial that leaks be found and corrected before a small problem becomes a severe problem. In this business, there is old adage: ‘Everything leaks, it is just a matter of when.’
Leaks translate into lost cash. Allowing leaks to exist without a leak identification and repair program will add a hidden cost to the products a company makes. These leaks are like having small pinholes in your automobile gas tank. After a while, you’ll notice how they’ve created a hole in your wallet. The time to stop them is now; energy is unlikely to get less expensive.
If you are an employee in plant where leaks are not addressed, safety and the environment can suffer an unintended consequence. There are many potentially explosive gases in plants, such as hydrogen and natural gas, that can leak. In addition, there are gas leaks that can also have a negative impact on the environment, such as greenhouse gases. Did you know that something as apparently innocuous as a compressed air leak could have environmental consequences?
Is an air/gas leak audit cost-effective even in a smaller plant? Yes. Leak detection is important in any size of plant. Even in a smaller plant, financial survival and competiveness are very important. In larger plants, the impact of leaks may be exponentially more costly.
An audit of a large plant typically finds between $5,000-$10,000 per day of losses through leakage. Once a plant gets a handle on its leaks, it not unusual for it to be capable of shutting down the operation of an extra compressor. Most facilities would want such audits done semi-annually or at least once a year.
Enlist the help of employees
When leaks become large enough, they become audible and can be detected without the need for ultrasonic scanning. Heighten the awareness of all individuals in each department. Ask them to report leaks that may be audible. If you do not already own ultrasonic leak detection equipment, consider the purchase of such equipment and train one or more individuals in each department to perform their own leak audits.
These air/gas leak auditors should be recognized as energy conservation champions. As energy continues to become extraordinarily expensive, plants must take steps to conserve it.
In some cases, you can get by with less, but to do the best job, you need the best equipment. An investment in good equipment makes your job easier and you ultimately save time. As they say, time is money. In the end you will thank yourself for using a reliable instrument, especially when you keep the equipment properly calibrated and take all necessary steps to maintain the instrumentation.
Compressed gases can
be costly in more than the obvious ways. The cost of producing or purchasing the gas is one factor. Safety, the environment, and equipment degradation caused by leaks and equipment inefficiencies can all add up in many ways to have an impact on a company’s ability to compete and maintain profitability. A planned, comprehensive leak survey program can provide savings that can improve plant-wide productivity and profitability.
Bruce Gorelick is vice-president of Enercheck Systems, Charlotte, NC Alan Bandes is vice-president of marketing for UE Systems, Elmsford, NY For more information, visitwww.enerchecksystems.comandwww.uesystems.com.
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