Technical Data for PE and PVC pipes

Formula: Water flow diagrams are calculated according to the Colebrook- White formula:

Q = -6.95 x log	(	0.74	+	k	)	x Di² x vDi x I
		Di x Di x I x 106		3.71 x Di

Q = Water discharge (m³/s)
Di = Internal diameter (m)
I = Frictional loss (m/m) (number)
k = Frictional resistance (m)

For diameter = 200mm, k = 0.00001m
For diameter >2400mm, k = 0.00005m

The curves are designated by trade name (external diameter) but calculated according to the pipe internal making it possible to read the capacity of the pipe direct without having to interpolate between the curves.

From the diagram the frictional loss of the plastic pipe itself appears. Individual resistances such as bends, valves, tees, reducers, inlet and outlet taps etc. are not taken into account.

For most water supply projects the different individual resistances will normally not be calculated. In such a case 2-5% is added to the frictional loss of the pipe.