Our Guide to Compressed Air Piping (Distribution Systems)

Throughout industry, compressed air is so widely used that it is often regarded as the fourth utility, after electricity, natural gas and water.

Just like gas, electric and water, compressed air requires a distribution system that works efficiently.

A brief history of compressed air distribution piping

Black Iron
For many years the only pipe available was black iron. This wasn’t the best solution as it suffered from porosity and leaks due to corrosion along the length of the pipe and threads.

Galvanised Pipe
Galvanised pipe was then introduced, but it also suffered from corrosion problems where the pipe was cut and threaded, as well as restrictions due to rough internal finish and reduction. Today it is still used for compressor house installations, especially for headers, due to its strength and rigidity.

Plastic (Solvent weld type)
No corrosion problems, but larger sizes are required because of the thickness of the wall. Plastic piping is also susceptible to damage from UV and certain airborne solvents found at printer works and chemical companies. It’s also susceptible to some compressor oils (it has been known to show signs of crazing and even shattering, which could cause serious injuries). However, the latest innovations in plastics have alleviated some of the above problems.

Square Profile Aluminium Tube (Extruded)
Various companies have started supplying square profile aluminium tube. This has no corrosion problems; however, its profile is quite large due to having a round inner diameter and square external. This means that special equipment is needed to ensure it is square cut to enable the inserts to fit correctly, which has cost implications.

Round section (thin wall) Extruded Aluminium Tube:
The latest air mains are ideally installed using extruded thin-walled aluminium pipework systems. The smooth bore reduces flow losses and the pipework diameter can be reduced compared with galvanised pipe. The fittings are matched to the internal diameter to lessen turbulence hence restrictions = energy saving. Because of its low weight, it is easy to install, with less stress on the fixings.

Unlike threaded pipework, there is no cutting oil or swarf left in the piping – and it’s easy to extend or add extra drops for added versatility. Extra drops can be added while the system is under pressure, provided you use the correct tools, which cuts out any loss in production. An anodised outer coating is coloured for the majority of gases and vacuum systems.

All the above piping systems above have a place in industry depending on their environment and use.

If you would like advice on which piping system is correct for your company please contact PPS.