Basics of the Compressor Room

EXAIR Corporation has staked our reputation on a keen ability to help you get the most out of your compressed air system since 1983.  Now, the bulk of our expertise lies in the implementation and proper use of engineered products on the demand side, but we fully recognize that there are critical elements for optimization on the supply side too.  And that, quite literally, starts in the compressor room.  This is not an exhaustive, specifically detailed list, but here are some you might consider to get the most from the (again, quite literally) beginning:

  • Location.  If you’re building a new facility, or doing a major rehab of your existing one, having the compressor room as close as practical to the point(s) of use is best, IF all other things are equal.  You’ll use less pipe if you don’t have to run it so far.  You’ll also be able to use smaller diameter lines because you won’t have to worry about line loss (pressure drop due to friction as the air flows through the total length) as much.
  • Location part 2.  If all other things are NOT equal, having the compressor room close to the point of use may not be best for you.
    • Your air compressor pulls in air from the immediate environment.  It’s better to go with longer and bigger pipe in your distribution system than it is to put your compressor in a location where it’ll pull in dust & particulate from grinding operations, humidity from a boiler plant, fumes from chemical production, etc.
    • There are some pretty darn quiet air compressors out there, but there are some pretty loud ones too.  Especially in small to mid size facilities, putting the compressor in an area that upsizes the required piping is still likely a better idea, due to the downsizing of the noise levels that personnel will be exposed to.
  • Environment.  No matter where your compressor is located, the machine itself should be protected from heat and other harsh environmental elements.  That means if it’s inside the plant, the compressor room should be adequately ventilated.  In some situations, the compressor may be best installed outside the plant, in its own building or protective structure.  This should be designed to protect against solar load…in addition to the high temperature associated with a hot summer day, the sun’s rays beating down on your air compressor will radiate a tremendous amount of heat into it.
  • Filtration.  Whatever is in the air in your compressor room is going to get into your compressed air.  This is doubly problematic: particulate debris can damage the air compressor’s moving parts, and it can likewise damage your pneumatic cylinders, actuators, tools, motors, etc. as well.  Make sure the intake of your compressor is adequately filtered.
  • Maintenance.  Air compressors, like any machinery with moving parts, require periodic preventive maintenance, and corrective maintenance when something inevitably breaks down.  There should be adequate space factored in to your compressor room’s layout for this.  The only thing worse than having to fix something is not having the room to fix it without taking other stuff apart.
Patrick Duff, a production equipment mechanic with the 76th Maintenance Group, takes meter readings of the oil pressure and temperature, cooling water temperature and the output temperature on one of two 1,750 horsepower compressors. Each compressor is capable of producing 4,500 cubic feet of air at 300 psi. The shop also has a 3,000 horsepower compressor that produces 9,000 cubic feet of air at 300 psi. By matching output to the load required, the shop is able to shut down compressors as needed, resulting in energy savings to the base. (Air Force photo by Ron Mullan)

These are a few things to consider on the supply end.  If you’d like to talk about how to get the most out of your compressed air system, EXAIR is keen on that.  Give us a call.

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

Understanding Compressed Air Supply Piping

An important component of your compressed air system is the supply piping. The piping will be the middle man that connects your entire facility to the compressor. Before installing pipe, it is important to consider how the compressed air will be consumed at the point of use.  You’ll also need to consider the types of fittings you’ll use, the size of the distribution piping, and whether you plan to add additional equipment in the next few years. If so, it is important that the system is designed to accommodate any potential expansion. This also helps to compensate for potential scale build-up (depending on the material of construction) that will restrict airflow through the pipe.

Air Compressor
Air Compressor and Storage Tanks

The first thing you’ll need to do is determine your air compressor’s maximum CFM and the necessary operating pressure for your point of use products. Keep in mind, operating at a lower pressure can dramatically reduce overall operating costs. Depending on a variety of factors (elevation, temperature, relative humidity) this can be different than what is listed on directly on the compressor. (For a discussion of how this impacts the capacity of your compressor, check out one of our previous blogs – Intelligent Compressed Air: SCFM, ACFM, ICFM, CFM – What do these terms mean?)

Once you’ve determined your compressor’s maximum CFM, draw a schematic of the necessary piping and list out the length of each straight pipe run. Determine the total length of pipe needed for the system. Using a graph or chart, such as this one from Engineering Toolbox. Locate your compressor’s capacity on the y-axis and the required operating pressure along the x-axis. The point at which these values meet will be the recommended MINIMUM pipe size. If you plan on future expansion, now is a good time to move up to the next pipe size to avoid any potential headache.

After determining the appropriate pipe size, you’ll need to consider how everything will begin to fit together. According to the Best Practices for Compressed Air Systems from the Compressed Air Challenge, the air should enter the compressed air header at a 45° angle, in the direction of flow and always through wide-radius elbows. A sharp angle anywhere in the piping system will result in an unnecessary pressure drop. When the air must make a sharp turn, it is forced to slow down. This causes turbulence within the pipe as the air slams into the insides of the pipe and wastes energy. A 90° bend can cause as much as 3-5 psi of pressure loss. Replacing 90° bends with 45° bends instead eliminates unnecessary pressure loss across the system.

Pressure drop through the pipe is caused by the friction of the air mass making contact with the inside walls of the pipe. This is a function of the volume of flow through the pipe. Larger diameter pipes will result in a lower pressure drop, and vice versa for smaller diameter pipes. The chart below from the Compressed Air and Gas Institute Handbook provides the pressure drop that can be expected at varying CFM for 2”, 3”, and 4” ID pipe.

ccfdfcfdddfcvgdsdfzxcv.png
Air Pressure Drop

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

 

Images Courtesy of  the Compressed Air Challenge and thomasjackson1345 Creative Commons.