Exploring Optimization: Standards And Certifications For Compressed Air Audits

EXAIR Corporation has devoted almost 37 years to manufacturing engineered products aimed at the most efficient, quietest, and safest use of compressed air.  Sometimes, a caller has recognized that an open pipe blow off, for example, is loud, wasteful, and unsafe, and just wants to install an engineered product that they know will be an improvement.  They may not be interested in precisely quantifying the savings…they’ll just notice that their lone air compressor runs less, and their electric bill isn’t as high anymore.

Others, however, may have a compressed air system that comprises multiple compressors, with advanced controls, and they may have specific operational goals in regard to how the individual compressors are loaded and controlled, or maybe even eliminating the need to run particular compressors all the time…or at all.

The skills & knowledge necessary to handle such a task are within the confines of discipline of mechanical engineering, but oftentimes, specialized training is needed to effectively conduct an audit in order to formulate an execute such an optimization plan.  If you’re interested in pursuing this training, or working with trained personnel, here’s a brief description of the training that’s available, and how you can find people that have been through it:

  • The American Society of Mechanical Engineers (ASME) publication “Guidance for ASME EA-4, Energy Assessment for Compressed Air Systems” details the requirements for performing an audit.  Since there are so many configurations of compressed air systems, it’s not a “step by step” procedure, but it IS handy for developing one, if you know how.  Speaking of which…
  • The Compressed Air & Gas Institute (CAGI) offers training & certification in two categories:
    • Certified Compressed Air System Specialists (CCASS) – these are qualified experts who have demonstrated competence (by means of a comprehensive examination) in skills and abilities relating to the design, service, sales, and installation of compressed air systems & equipment.
    • Certified Compressed Air System Assessors (CCASA) – in addition to CCASS certification, these individuals has passed another comprehensive examination, verifying their knowledge and skills as practitioners performing assessments (audits) of compressed air systems.

Both of these certifications comply with the ISO 17024 Conformity Assessment standard, which governs General Requirements for Bodies Operating Certification of Persons in any field of endeavor.  This means that, not only have certified personnel all passed the same tests regardless of where they are, but the tests they’ve passed meet stringent standards for examining knowledge level and competence in these fields.

Bottom line: if you want an in-depth, accurate evaluation of the efficiency of your compressed air system, experts are available.  The Compressed Air & Gas Institute even publishes directories so you can find them in your area.

Russ Bowman
Application Engineer
EXAIR Corporation
Visit us on the Web
Follow me on Twitter
Like us on Facebook

Finding & Fixing Leaks: The Benefits of Creating a Leak Detection Program

Leaks in a compressed air system can be a substantial source of wasted energy. A facility that hasn’t maintained their compressed air system will likely have a leak rate around 20-30% of the total air production.  But with a leak detection plan you can reduce air leaks to less than 10% of the compressor output.

uhd

Along with the energy waste, leaks will contribute to higher operating cost.  Leaks cause a drop in system pressure, which can make air tools operate poorly, harming production cost and time. In addition, by forcing the equipment to cycle more often, leaks shorten the life of almost all system equipment, including the compressor. Increased running time can also lead to added maintenance and increased downtime. Finally, leaks can lead to adding unnecessary compressor volume.

Since air leaks are almost impossible to see, other methods must be used to locate them. The best way to detect leaks is to use an ultrasonic acoustic detector, Like EXAIR Ultrasonic Leak Detector (ULD). This unit can recognize the high frequency hissing sounds associated with air leaks. A person using the ULD only needs to point it in the direction of the suspected leak. When a leak is present, an audible tone can be heard with the use of the head phones, and the LED display will light.  Testing various unions, pipes, valves and fittings of a complete system can be done quickly and effectively at distances up to 20’ away!

uhd kk

uhd e

The advantages of ultrasonic leak detection include flexibility, speed, ease of use, the ability to test the system while machines are running, and the ability to find a wide variety of leaks. They involve very little training, operators often become competent after 10 minutes of training.

Due to the nature of ultrasound, it is directional in transmission. For this reason, the signal is loudest at its source. By scanning around a test area, it is possible to very quickly target in on a leak site and pin point its exact location. For this reason, ultrasonic leak detection is not only fast, it is also very accurate.

An active leak prevention program will embrace the following components: identification, tracking, repair, verification, and employee participation. All facilities with a compressed air system should establish an aggressive leak reduction program. A team involving managerial representatives from production should be formed to carry out this program.

A leak prevention program should be part of an overall program intended to improve the performance of compressed air systems. Once the leaks are found and repaired, the system should be started from the beginning until all leaks are addressed.

A good compressed air system leak repair program is very important in maintaining the efficiency, reliability, stability and cost effectiveness of any compressed air system.

kkkk

“First a Plant Engineer or Maintenance Supervisor must realize that leak repair is a journey, not a destination. An ongoing compressed air leak monitoring and repair program should be in place in any plant that has a compressed air system.” Explains Paul Shaw, a General Manager for Scales Industrial Technologies’ Air Compressor Division, and an Advanced CAC Instructor, “Leak identification and remediation with a high quality repair can lead to substantial energy savings that typically has a very rapid payback, usually a year or less. In the hundreds of leak audits and repairs that we have done we’ve found that the quality of the repair is critical to ensuring the customer receive the most value for his investment and that the leak remains repaired for as long as possible. From there, constantly monitoring for compressed air leaks and repairing them as they occur can help the plant continue to reap the energy benefits.”

Above is an excerpt from “Best Practices for Compressed Air Systems”, Appendix 4.E.1.

To discuss your application and how an EXAIR Intelligent Compressed Air Product can help your process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer

Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

Intelligent Compressed Air: Membrane Dryers

A critical component on the supply side of your compressor system is the dryer. Atmospheric air contained within a compressed air system contains water vapor. The higher the temperature of the air, the more volume of moisture that air is capable of holding. As air is cooled, this water vapor can no longer be contained and this water falls out in the form of condensation. The temperature where this water will drop out is referred to as the dew point.

At a temperature of 75°F and 75% relative humidity, approximately 20 gallons of water will enter a 25HP compressor during a 24-hour period. As air is compressed, this water becomes concentrated. Since it’s heated during the compression process, this water stays in a vapor form. When this air cools further downstream, this vapor condenses into droplet form.

Moisture within the compressed air system can result in rust forming on the inside of the distribution piping, process failure due to clogged frozen lines in colder weather, false readings from instruments and controls, as well as issues with the point of use products installed within the system.

The solution to this problem is to install a dryer system. We’ve spent some time here on the EXAIR blog reviewing refrigerant dryers , desiccant dryers, deliquescent dryers, and heat of compression dryers. For the purposes of this blog, I’m going to focus on one of the newer styles on the market today: the membrane dryer.

Membrane Dryer

In a membrane dryer, compressed air is forced through a specially designed membrane that permits water vapor to pass through faster than the air. The water vapor is then purged along with a small amount of air while the rest of the compressed air passes through downstream. Generally, the dew point after the membrane dryer is reduced to about 40°F with even lower dew points also possible down to as low as -40°F!

With such low dew points possible, it makes a membrane dryer an optimal choice in outdoor applications that are susceptible to frost in colder climates. Membrane dryers also are able to be used in medical and dental applications where consistent reliability is critical.

A membrane dryer does not require a source of electricity in order to operate. The compact size makes it simple to install without requiring a lot of downtime and floor space. Since they have no moving parts, maintenance needed is minimal. Most often, this maintenance takes the form of checking/replacing filter elements just upstream of the membrane dryer. The membrane itself does need to be periodically replaced, an indicator on the membrane dryer will display when it needs to be changed. If particular instruments or processes in your facility are sensitive to moisture, a membrane dryer might be the best option.

However, there are some drawbacks to these types of dryers. They’re limited to low capacity installations, with models ranging from less than 1 SCFM up to 200 SCFM. This makes them more applicable for point-of-use installations than for an entire compressed air system. The nature in which the membrane dryer works necessitates some of the air to be purged out of the system along with the moisture. To achieve dew points as low as -40°F, this can equate to as much as 20% of the total airflow. When proper filtration isn’t installed upstream, oils and lubricants can ruin the dryer membrane and require premature replacement.

Make sure and ask plenty of questions of your compressor supplier during installation and maintenance of your system so you’re aware of the options out there. You’ll of course want to make sure that you’re using this air efficiently. For that, EXAIR’s wide range of engineered Intelligent Compressed Air Products fit the bill. With a variety of products available for same-day shipment from stock, we’ve got you covered.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

 

Membrane Dryer Schematic – From Compressed Air Challenge, Best Practices for Compressed Air Systems, Second Edition

 

Laminar vs. Turbulent Flow

Laminar flow is an fundamental component of compressed air efficiency. Believe it or not, laminar flow is controlled exclusively by the airline used in a compressed air system. To fully understand the effects of laminar flow in a compressed air system, we need to explain exactly what it is.

Fluids & gases are unique in their ability to travel. Unlike solid molecules that remain stationary whose molecules tend to join others of the same kind; fluid molecules aren’t so picky. Fluid molecules, such as gases and liquids, partner with different molecules and are difficult to stop.

Laminar flow describes the ease with which these fluids travel; good laminar flow describes fluid travelling as straight as possible. On the contrary, when fluid is not travelling straight, the result is turbulent flow.

PVDF Super Air Knife
Laminar Flow

Turbulent air flow results in an inefficient compressed air system. This may not seem like a major concern; yet, it has huge impacts on compressor efficiency. Fluid molecules bounce and circle within their path, causing huge energy wastage. In compressed air systems, this turbulent airflow results in a pressure drop. How do you avoid this from happening? It all comes down to compressed air system design.

Flow type
Laminar vs. Turbulent Flow

The design and material of the air pipe, as well as the positioning of elbows and joints, has a direct connection to laminar flow and pressure drop. To avoid high energy consumption of your compressed air system, reducing pressure drop is key.

If your system is experiencing high pressure drop, your compressor has to work overtime to provide the needed air pressure. When your compressor works overtime, it not only increases your maintenance costs, but also your energy bills.

To discuss your application and how an EXAIR Intelligent Compressed Air Product can help your process, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
Send me an email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS