Pipe material plays an essential role in determining the flow, pressure drop and quality of compressed air. However, not all materials are suitable for compressed air systems. A number of materials can be corroded by lubricants from the compressors, leading to catastrophic failure, contamination, debris and leaks in the air stream. Pipe material does also affect pressure loss caused by friction.
Following are the most common types of piping material, their advantages and disadvantages.
PVC pipe is a common material sometimes used in ignorance for compressed air systems. It is readily available, cost-efficient and easy to install. However, as with many plastics, PVC gets brittle over time. The material can easily break and shatter. Air compressor oils and heat from compressed air accelerate the degradation of PVC.
Galvanised piping is commonly used for general plumbing and water distribution. While it can resist moisture from compressed air piping, corrosion does occur internally and pieces of rust from the pipe may flake off, causing damage to pneumatic tools, cylinders and other components. Galvanised piping is much slower to install, joints are prone to leakage and has a higher coefficient of flow resistance and is a material not worth considering for compressed air systems.
Black pipe is another commonly used pipe material because of its strength, durability and ease of installation. One downside of using black pipe is rust contamination. Black pipe is uncoated, and moisture from the compressed air leads to rusting. Installing black pipes requires a significant amount of time and causes damage to pneumatic tooling.
Stainless steel piping is recommended for compressed air systems because the material has a lower risk of corrosion. Much like the black pipe, it is robust and highly durable. Installing traditional stainless steel fittings and piping tends to be a long process unless press fittings are utilized. Pipe threads may gall and freeze up, causing difficulty in disassembly.
Copper pipes are generally considered non-corrosive and easy to weld and cut. It also has a wide range of available fittings because it is commonly used for plumbing. While it makes for aesthetically pleasing installations, soldering copper is time-consuming and requires highly specialised skills, and copper does develop green corrosion that can contaminate pneumatics and processes.
Aluminium, on the other hand, is lightweight, easy to handle, and highly recommended for clean air applications. The material is non-corrosive, allowing the compressed air network to deliver clean dry air throughout the system and operate more efficiently for far longer than other alternatives.
Aluminium pipe is also heat-resistant. It has minimal expansion and contraction in extreme temperature shifts. Compared to PVC, which is prone to sagging and bowing, aluminium maintains its form.
PE100 is the highest grade of polyethylene piping commercially available and is also recommended to provide clean, corrosion free, economic, fast to install and reliable compressed air pipework. It is important to choose a reputable brand like Max air that meets the Australian Standard with the required safety margins. Its smooth bore is ideal for reducing pressure drop which also reduces operating costs.
Leaks may be one of the most significant challenges to a piping system’s efficiency, but there are other factors for consideration. The presence of sharp angles in the design of the pipes impedes the speed of flow, and creates pressure drop- this means the compressor has to work harder and tools and pneumatic equipment work slower.
When choosing a piping system for your business, minimise right-angle elbow corners because they will cause turbulence in the air pressure system and reduce pressure delivery. Following a straightest path possible in air flow will deliver the most efficient results.
Air piping without efficient ring systems and only small diameters can also lead to a sudden drop in pressure while your pipes are in use, affecting your overall energy consumption. The less pressure there is, the more energy you need to keep the pump systems running. Every bar of increase or decrease in pressure usually requires x2 increase or decrease in power. With the appropriate piping design, you can save about five per cent in power costs per 10psi (68kpa) decrease at the compressor.
When you purchase compressed air piping systems that are subject to corrosion, they can become clogged with dirt and liquids over time. If left untreated, clogged pipes can lead to wear of seals and moving parts. Choosing the right type of piping will prevent grime accumulation and microbiological growths. Also, aluminium pipes are one of the most corrosion-resistant piping options, giving you strong and lightweight air piping solutions.
In a typical industrial operating environment, temperatures fluctuate throughout the day. It can be extremely hot during the day and especially cold at night, affecting the condensation in compressed air systems. Poorly designed compressed air systems with changes in temperature, causes moisture to precipitate within the system. If there’s too much moisture in your equipment, it can lead to rust, system breakdowns and costly maintenance.
You can put your staff’s safety at risk if you invest in the wrong type of piping for breathing air applications. Some substances carried by air piping systems can be potentially dangerous to health. Any safety concerns that your piping systems have could also severely affect your business. Be sure to choose the right compressed air line systems from a provider you can trust.
Compressed air has enormous stored energy and the piping needs to be clearly and readily identified. If your pipes have incorrect labels or non-specific colour coding, it can do your staff and your business harm. Any issue or need could arise from time to time – it’s important that your pipes have the correct markings so that you can easily troubleshoot or modify your piping systems.
Air Energy is a leading provider of compressed air systems across Australia. Our company has been installing and supplying industrial pipework systems for more than 20 years. With our in-depth industry knowledge and vast scope of experience, we are determined to give each client personalised ‘best practice’ solutions.
Air Energy has a team of dedicated industry-leading consultants, contractors and mechanical designers who provide a comprehensive range of equipment and services for businesses in Australia.
Maximize productivity and protect your equipment with our precision-engineered air compressor filters. Say goodbye to clogged lines and hello to smooth operation.
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Traditionally up to about 25 years ago galvanised pipe and sometimes copper was the standard practice for compressed air. The newer advances in materials have multiple advantages especially in speed of installation, but also elimination of leaks.
Polyethylene pipe was the biggest breakthrough, especially since the commercialisation of PE100 giving a superior performance in pressure capacity and reduction of wall thickness. PE is inert, does not support micro-organisms, is very easy to cut and join.
Aluminium is often the preferred and highly recommended material for compressed air pipes. This is because it is lightweight, colour coded and more corrosion-resistant than copper or galvanised iron. However stainless steel is often a preferred option due to its higher corrosion resistance and actually cheaper cost. In SS the pressfit system has revolutionised the installation time.
You can also go for a bigger size pipe for your compressor. A larger pipe size may increase the initial material cost, but it will significantly lessen (or eliminate) the pressure drop and by allowing for future growth and expansion, or potential new equipment save money in the long run.