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Pipe Size & Friction Loss - A major issue
As water goes up a pipeline it encounters friction as it travels past the wall of the pipe. As the water flow increases, so the pipe friction increases. The pipe material and the smoothness of its bore, also has an effect on pipe friction. We try to ensure that the pipe size is matched to the job at hand.
Friction in water pipes is measured in metres of pressure loss, per 100 metres. E.g: If we were trying to push 50 litres per minute through 100 metres of 1" Class B Polypipe, we would encounter 13 metres (19psi) of pressure loss. This means that if your pump is capable of making 30 metres of pressure (43psi) we would lose 13 metres (19psi) of its performance at the other end of the pipe.
If we increase the volume to 100 lpm the friction loss would increase to 48 metres (69psi). Our pump above was only capable of making 30 metres of pressure, so it cannot possibly produce enough pressure to pump this volume through this size pipe. There are two solutions; increase the size of the pipe, or increase the performance of the pump.
If we tried to push 200lpm up the same pipe we would encounter a massive 172 metres (243psi) of pressure loss. No pump can overcome this pressure loss - the obvious answer is to increase the pipe size.
Listed below are friction loss tables for the most common pipe materials:
Polypipe Class B
Polypipe Class 12
Rubber Hose
PVC Pipe Class 12
Copper Type B
Galvanized Steel
Steel pipe commercial
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