Understanding the Common Materials Used for HVAC Pipework Fabrication

Posted on: 29 August 2017

 In the heating, ventilation, and air conditioning (HVAC) industry, piping systems are used in a variety of applications including the transport of fluids, as valves to control the flow of fluids, or as pipe fittings. For them to play these roles perfectly well, the materials used in their construction needs to fit the purpose. General purpose piping is usually constructed in plain steel, copper, galvanised steel, or cast iron. For special HVAC applications such as those requiring corrosion resistance, nonmetallic materials such as plastic, fibreglass, or glass are used. The following are the common materials used in HVAC piping.

Black Steel

Uncoated steel, commonly referred to as black steel due to its dark-coloured iron oxide which forms on the surface, is used in fabricating pipes for low pressure water heating applications.

Galvanised Steel

This pipe-making material comprises steel coated with zinc to prevent it from corrosion. In HVAC, galvanised steel pipes are used for interior plumbing. Other applications include outdoor construction of structures such as handrails and fences.


Copper is a material commonly used both for air conditioning and plumbing. There are 4 main types of copper pipes used in residential plumbing namely K, L, M, and DWV. The K pipes have very thick walls and are commonly used in underground burial applications. The L pipes are used for general purposes, while the M pipes are used in applications that require low pressure. DWV copper pipes on the other hand have the thinnest walls and are mainly used for vent, waste, and drain. K and L copper pipes are usually fabricated in two tempers; the first is known as drawn temper and the second one annealed temper. The drawn temper pipe is fabricated by pulling the tube through a series of steel dies so as to reduce its diameter. The annealed copper tube which is softer than the drawn tube is passed through an annealing furnace heated to 700 degrees Celsius.

PVC Pipes

These tubes are made from a combination of plastic and vinyl material. They are long lasting and hard to damage. Since PVC pipes do not rot, rust, or wear out, they are most commonly used in underground wiring, sewer lines, and water systems.

Other types of piping material include polybutylene, low-density polyethylene, and polypyrene. Before buying pipe work for your HVAC project, it is important you find out the material and whether it is suitable for your specific pipework installation from a place like Degree C Pty Ltd