Companies requiring an audit usually do their best to conserve energy. Most energy engineers realize the high cost of energy drain from the power wasted by air compressors trying to maintain preset air pressures. Much of this energy drain stems from air leaks, which can not only negatively impact the system as a whole, but also can affect the environment and quite possibly the health of personnel who have to work around them.

Negative impacts on control
technician looksAir leaks can impact processes negatively. Control and pressure reducing valves are relied upon to control the manufacturing process. Precise control is critical to the products produced and to indoor environments.

Compressed air systems in a plan may control more than just the air cylinders, motors, and other actuators on automated equipment. For example, in biotech facilities, compressed air may control ventilation systems, where maintenance of humidity and temperatures are an utmost priority. If the degree of humidity in a controlled biogenetic research facility goes awry, it can ruin months or years of research. Loose connections or splits in tubing can adversely impact 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 leak audits on a regular basis, or make arrangements with a competent firm to have audits conducted periodically.

Many critical components in a compressed air system require validation to ensure they are operating to original specifications. Likewise, noncritical system components need to be assessed for leakage. They include, but are not limited to pressure- and directional-control valves, fittings, hoses, thread connections, FRLs, and quick-acting couplings. If they are leaking, they not only waste energy, but may reduce system productivity and product quality.

Unseen sources
One of the challenges to finding air system leaks is that many sections of system piping may be inaccessible. Just because a leak can’t be seen or heard doesn’t mean it doesn’t exist.

Most compressed air systems require not only clean, but dry air. Wherever moisture is separated out of the compressed air stream, some form of drain must be provided to remove the water. A manual drain may be used in small systems, but plant air systems generally incorporate automatic drain traps. Drains should be located in the lowest portions of system piping, which makes them difficult to reach. Just because they are hard to get at does not diminish their potential for leakage.

ultrasound instrumentWhen a drain trap sticks in the closed position it causes the condensed water to accumulate within the system. Thus, the air will contain water that can impede proper operation and cause long-term effects, such as rust, dirt, and corrosion. This makes it important to repair or replace drain traps that are stuck closed.

If a drain valve fails in the open position, energy is wasted by allowing the compressed air to escape to atmosphere without having done any work. Because 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 drain traps.

Valves, solenoids, and other components can plug or stick in the open position. Also, the gaskets between banks of valves begin to leak when water has not been drained from the compressed air system. Oil carryover from compressors can degrade O-rings and gaskets, causing them to leak. If portions of the air system piping

are routed outdoors, and temperatures can drop below freezing, the air lines and the equipment to which it leads can freeze. Once frozen, the portions that freeze can crack and be permanently damaged.

The air system is like a food chain, in that a shortcoming in one component in the system can affect others.