The compressed air pipework system is to transfer compressed air to certain points of usage. Compressed air requires enough volume, quality and force to appropriately power the mechanism that utilizes the compressed air.
The different types of piping materials used for compressed air pipework can be divided in two categories that is metal and non-metal.
Non-Metal Pipe – These are generally popular as plastic pipes and has been serving the compressed air piping, due to the following reasons.
1. It is light and easy to handle.
2. It does not need special tools for installation.
3. It is non-corrosive.
4. It should be glued with appropriate material during installation.
5. Installation labor cost is reasonable in comparison to metal pipes.
Metal Pipe – Stainless steel, black iron, aluminum, copper, etc having appropriate thermal/pressure characteristics.
1. Stainless Steel – For compressed air pipework material stainless steel is best because when exposed to non-lubricated air and particularly high-level acid condensation. Stainless steel installs well on welding. Ring seals are used that work well. Installation cost and piping material is overall economical.
2. Black iron pipe – In compressed air pipework system, when black iron pipes are exposed to condensation it will corrode. It is heavier than aluminum and copper, hard to install and less expensive.
3. Copper Pipe – It is commonly selected for responsive air systems. If it is connected appropriately, it is very rough. The temperature limit working of copper piping is 400 degree Fahrenheit. Even if the solder melts, copper pipes will be highly resistant to intense temperatures.
4. Aluminum Pipe – It is popularly accepted today because it provides smooth inner surface and is flexible to meet the regularly changing compressed air distributions as required.
An appropriate inlet pipe delivers the filtered air to the compressor without any loss of pressure and there should not be any kind of self-contamination created inside.
Galvanized or aluminum inlet piping resists corrosion much better than the common iron pipe. Overtime, due to corrosion the galvanizing material begins to peel. Now the inlet pipe has the potential to damage the compressor system.
An inlet pipe made from stainless steel is the best material as long as the installation is properly carried out and the inside is cleaned well. Several thermoplastic materials are suitable for inlet piping. So, make use of proper thermoplastic material or stainless steel materials that are suitable for inlet piping.
The discharged air from compressors is approximately 250 to 350 degree F for oil-free rotary, centrifugal and reciprocating types. It is about 200 to 220 degree F for lubricant types, so the pipe must withstand those temperatures. There are after coolers that allow the temperature to drop down to approximately 100 degree F. However, if the after cooler fails must also be a point of consideration.
Compressed air, when condensed is apt to be acidic and in oil-free compressors the air is extremely aggressive. The main aim of interconnecting pipes is to transfer the air to filters and dryers without any loss in the pressure. Additionally, there must be no self-contamination present. Therefore, stainless steel can resist corrosion much better than galvanized and thermoplastic piping.