Many industries use compressed air for various purposes, from automotive uses with pneumatic tools, general manufacturing, recreation, mining, transportation, water waste treatment, or even food and health care, such as dentistry. For the compressed air to be used, it must be sent through piping that could be made from metal, plastic, PVC, steel, aluminum, iron, copper, or other materials.
Pipes are what take the compressed air that is sent through the compressed air systems to deliver it to its source and make it useable. Depending on what the compressed air is used for, the type of pipes used to deliver the compressed air matters.
Why the Right Pipe Matters
When air is pressurized above atmospheric pressure, it is called compressed air. Compressed Air Systems take this safe pressurized air and transform it into a usable energy source.
Like the air we breathe, compressed air consists of about 78% nitrogen, 21% oxygen, water vapor, and less than 2% of other gases. This mixture of gases is forced into a compact space which brings the molecules closer together and stores them at high pressure.
When these molecules are concentrated and placed under pressure to be forced through a conduit, or piping, it is essential to make sure the pipe used will withstand this kind of delivery system.
Depending on its use and whether the compressor is an oil-lubricated rotary screw, oil-free rotary screw, oil-free turbo compressor, here are the best piping materials for compressed air systems.
Metal piping has been used for years and is a very popular choice. Metal won’t degrade when it comes into contact with lubricants or oils. So, if you are using a compressor that requires oil, metal is often a good choice.
Metal pipes are firm and durable, standing up to wear and tear without cracking, breaking, or warping.
On the downside, metal pipes tend to cost more than other types of piping. Metal pipes also often require professional installation, which takes time and money.
Generally speaking, plastic pipe tends to be more affordable, making it a preferred option to fit any budget. Plastic pipes are also straightforward to install. When used as a conduit for compressed air, plastic does not corrode.
However, keep in mind that there are many types of plastic piping. If plastic is used with compressed air, it will need to be sturdy enough to withstand contact with lubricants and oils without becoming damaged. It will also need to be OSHA-approved for use with your specific system.
PVC and CPVC piping
PVC stands for Polyvinyl chloride and is the third-most widely produced synthetic polymer of plastic globally.
CPVC stands for Chlorinated polyvinyl chloride. CPVC is a lot more flexible than PVC. It is a thermoplastic produced by chlorination o polyvinyl chloride resin. This type of PVC can withstand high temperatures and be used for industrial liquid handling to deliver hot or cold water through CPVC pipes.
While PVC and CPVC piping are very affordable and used in household plumbing and other uses, OSHA banned them for use in systems that use compressed air. PVC and CPVC piping are not recommended for this use because it does not have the strength to stand up to high pressure.
Additionally, this type of plastic tends to degrade when it comes into contact with any lubricant or oils used for the air compressor in systems that force compressed air throughout piping. If PVC and CPVC piping is used in a system that compresses air, it will likely leak or suddenly burst to cause potentially serious injuries and loss of function.
HDPE, ABS, PE
Certain plastics do not corrode, such as high-density polyethylene HDPE, Acrylonitrile butadiene styrene ABS, and polyethylene PE pipes will stand up to the lubricants and oils used with compressed air.
HDPE, ABS, or PE pipes are lightweight and easy to install since they don’t require any special supports or bracing. The pipes are simply glued or fused to fit. This type of plastic is easy to cut and fit, however a fusion tool is typically needed.
Of course, even the best plastic will not be as durable as metal piping that has been welded. Still, these high-quality plastic pipes can work very well with their smooth interior surface to allow maximum free-flowing air if they are rated for the pressure and approved for compressed air systems.
Galvanized Steel Pipe
Galvanized steel piping reduces corrosion significantly when used for compressed air delivery. However, the zinc coating on galvanized steel tends to degrade over time. When the coating starts to degrade, it could flake off inside the pipes and block the airflow, which can cause potential problems with the connected equipment.
Aluminum piping is lightweight, does not corrode, resists leaks, and is easy to install. Aluminum piping is also easy to modify after the system has been installed.
When aluminum is used in modular piping systems, it requires very few tools, no welding or brazing, without threading, and no special heavy supports to install and anchor. Since no welding or brazing is needed, no special hot work permit is required.
Black Iron Piping
Many consider black iron pipes to be a compressed air delivery system standard. Black iron pipe is solid and durable, standing up to wear and tear.
These iron pipes use traditional techniques, like welding and threading, to join them. Almost any plumber with access to fittings from a local hardware store can set them up. While black iron pipe has been efficiently used for years, they tend to be extremely heavy. They must be anchored and used with suspended piping systems. Sometimes they are difficult to cut and join, causing leaks to develop along where the connections meet. Another drawback with black iron piping is that the iron tends to corrode when it is exposed to moisture. If rust develops inside, pieces of the debris could block or break off into the airflow.
For much of the same reasons copper piping is popular in plumbing, it is also desired for use in systems that force compressed air through pipes. Copper pipe does not corrode, is relatively lightweight, and uses standard fitting techniques.
The major downside of copper piping is that it tends to be more expensive than other options. Costs have risen extensively over the years to the point where even coins no longer use pure copper as the primary metal. Copper also requires the use of a skilled plumber and welder to install it properly or to modify it once in place.
Stainless steel pipes are resistant to corrosion and are an extremely durable choice for use with compressed air. The stainless steel will not degrade or corrode, making it ideal to use with forced compressed air flow keeping rust at bay. However, some factors make stainless steel one of the last choices for use with compressed air. For starters, it is quite pricey.
Stainless steel is also prone to leakage around spots where the pipes are joined or welded together. A skilled plumber or pipe fitter will be necessary to join the piping and complete installation work adequately.
Choose the Best Compressed Air Piping
The ideal pipe material for a compressed air system will ultimately depend on what the air is being used for and the budget. When you have questions or need suitable piping for your compressed air system, reach out to our experts at Complete Engineered Solutions, a leading provider of compressed air, nitrogen generation, vacuum systems, and chillers.
Count on Complete Engineered Solutions to respond to your needs quickly with reliable service. Our knowledgeable and dedicated service team can help you choose and install the best type and size of piping for your specific air compression needs. Additionally, we can help you design the layout of your pipes to experience the most out of your system’s performance. Contact us today to have a specialized engineer help you design, install, or update your compressed air system.