Pipe friction

Pipe friction

Calculate the discharge head of a pump based on a few process values. The calculation is based on the Darcy-Weisbach formula and is based on the pumping of clean water. Resistance resulting from any fittings in the pipe system – such as bends, T-junctions and valves – is excluded. As a rule of thumb, for a simple pump arrangement you can compensate for this resistance by including 10% extra pipe length.

  • Capacity Q
    m³/h
  • Pipe diameter (inner) D
    mm
  • Pipe material, Roughness K
    mm
  • Pipe length L
    m
  • Vertical head
    m
  • Density ρ (water = 1.000 kg/m³)
    kg/m³
  • Dynamic viscosity η (water at 10°C = 1,3 mPA.s)
    mPa.s

Total head

m
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Pipe material, Roughness K
Material K-value (mm)
minimum
(new condition)		 nominal maximum
(strongly used condition)
Steel 0,1 0,5 2
HPE 0,05 0,5 1
PVC 0,05 0,5 1
Cast iron 0,2 1 2
Concrete 0,2 1 2
AC 0,1 0,5 1
GVK 0,1 0,5 1
Dynamic viscosity η
Temperature
T (°C)		 Dynamic viscosity water
η mPa.s
0 1.787
5 1.519
10 1.307
20 1.002
30 0.798
40 0.653
50 0.547
60 0.467
70 0.404
80 0.355
90 0.315
100 0.282