Tech Talk about Inch (Imperial) PVC Pipe
Imperial PVC Pipe Dimensions:
Imperial (inch) PVC pipe is measured in inches. The measurement relates to the nominal bore (the "approximate" bore) of the pipe, NOT the outside diameter.
The outside diameter (O.D) and internal diameter (I.D) are set out in millimetres in a table below for the different pipe pressure ratings (or "classes"):
Pipe Size
Outside Diameter(mm)
Wall thickness (mm) Class C, 9 bar
Wall thickness (mm) Class E, 15 bar
Wall thickness (mm) Class 7 (For threading)
Suitability
All of our inch industrial PVC (PVCU) pipe is supplied in a mid to dark grey colour and is WRAS approved for drinking water. As such, it is suitable for any potable water supply as well many other process fluids.
Temperature and Pressure
Our inch PVC pipe is specified to operate at temperatures of between 0 and 60 degrees centigrade (32 - 140 Fahrenheit). Users should be aware that PVC becomes more prone to impact damage at lower temperatures, and we recommend that if there is an impact risk at operational temperatures of below 5 Centigrade (41 Fahrenheit), then ABS pipe should be considered as an alternative. ABS pipe is far more impact resistant and will operate down to -40C (-40F).
Similar to other types of plastic pipe, the pressure rating for PVC pipe changes with temperature. As the temperature increases, the pressure rating falls. Use the table below to find the factor to multiply your pipe's pressure rating by to compensate for temperature:
Pressure Derating Factors for PVC Pipe
Operating Temperature deg C
De-Rating factor
Supporting Your Inch PVC Pipe and Fittings
PVC inch pipe should only be supported by either plastic clips or rubber lined galvanised clips over short spans. Using rubber lined clips over long spans can cause issues if the pipe expands and contracts with temperature, as the pressure from the clips prevents the pipe from moving in accordance to the expansion/contraction.
As temperature increases, your pipe supports should be closer together; however, the table below provides a distance, between each pipe support point, at 20 degrees Centigrade (increase by approximately 15% per 10 degrees above 20C):
