Tech Talk about Inch (Imperial) PVC Pipe
Do I need 10 bar or 16bar pipe?
Most applications operate way below 10 bar pressure and so this is by far the most widely used. Industries such as water treatment, pool and leisure, aquaculture, industrial process/factory lines etc. operate with maximums of 3-5bar pressure. It is often thought that just because a system has a pump it must be very high pressure, but in truth, most pump systems operate a just a few bar pressure. 16 bar pipe is usually only used in very specific high pressure industrial applications such as jet wash lines, high head hydropower schemes etc.
Pressure conversion - to pump water vertically by 10m requires 1 bar. More information is available inthis technical document
Dimensions
Unlike it's Imperial (inch) cousin, the metric pvc pipe system is measured on and accords to the precise outside diameter of the pipe. Like most things metric it is a more logical and easier to understand system. That is to say, a 50mm metric pipe will measure 50mm outside diameter, a 63mm will measure 63mm etc.
The table below gives details of metric pipe dimensions:
Pipe Size
Outside Diameter mm
Wall thickness 10 bar (mm)
Wall thickness 16 bar (mm)
Temperature Ratings
Metric PVC Pipe has an operational range of between zero and sixty degrees centigrade (32 - 140 degrees F), although operation at zero centigrade is not recommended, especially where there is risk of impact or stresses to the pipe. PVC pipe becomes increasingly brittle at lower temperatures and more prone to damage from impact.
Pressure Ratings
We supply our metric plastic pipe in 2 pressure ranges, 10 bar and 16 bar (147 and 235 psi) respectively. For most applications we would recommend our 10 bar pipe, as it is only in special pressure jet or other intense applications where pressures in systems exceed 10 bar (the equivalent of 100m of water head!). As plastic pipe changes properties (primarily ductility) as the temperature increases, so the pressure rating of the pipe also changes. The table below provides pressure de-rating multiples for each temperature and is used by multiplying the pressure rating of the pipe by the corresponding multiple in the table:
Pressure derating multiples of metric PVC pipe
Operating Temprature
De-Rating multiple
Pipework supports for Metric PVC
It is preferable ti use plastic pipe clips to support your PVC pipe. Using plastic clips prevents any "chafing" of teh pipe as it moves either as a result of vibration from machinery or from expansion / contraction during temperature changes. Rubber lined pipe clips are preferred by many installers as they are more versatile, however these should only be used in short pipe runs, as they grip the pipe very hard and can cause distortion during expansion and contraction. The table below gives the recommended spacing between pipe clips / supports. This should be increased by approximately 15% for every 10 degrees centigrade over 20 degrees.
Pipe Size (inches)
Minimum space (mm) between support centres
