Since pump curves often are in head - feet or meters, its may be necessary with a conversion to the common pressure scales used in pressure gauges - psi or bar.

[h=Converting Head to Pressure]3[/h] [h=Converting head in feet to pressure in psi]4[/h] Pump curves in feet of head can be converted to pressure - psi - by the expression:
p = 0.434 h SG (1)
where
p = pressure (psi)
h = head (ft)
SG = specific gravity
[h=Converting head in meter to pressure in bar]4[/h] Pump curves in meter of head can be converted to pressure - bar - by the expression:
p = 0.0981 h SG (2)
where
h = head (m)
p = pressure (bar)
[h=Converting head in meter to pressure in kg/cm2]4[/h] Pump curves in meter of head can be converted to pressure - kg/cm2 - by the expression:
p = 0.1 h SG (2b)
where
h = head (m)
p = pressure (kg/cm2)
[h=Converting Pressure to Head]3[/h] Since pressure gauges often are calibrated in pressure - psi or bar, it may be necessary with a conversion to head - feet or meter, commonly used in pump curves.
[h=Converting pressure in psi to head in feet]4[/h]
h = p 2.31 / SG (3)
where
h = head (ft)
p = pressure (psi)
[h=Converting pressure in bar to head in meter]4[/h]
h = p 10.197 / SG (4)
where
h = head (m)
p = pressure (bar)
[h=Converting pressure in kg/cm2 to head in meter]4[/h]
h = p 10 / SG (4b)
where
h = head (m)
p = pressure (kg/cm2)
[h=Example - Converting Pump Head - feet - to Pressure - psi]3[/h] The pressure - psi - of a water pump operating with head 120 ft can be expressed as:
p = (120 ft) 1 / 2.31
= 52 psi
[h=Feet of Head Water to psi]3[/h]
Feet Head psi
1 0.43
2 0.87
3 1.30
4 1.73
5 2.17
6 2.60
7 3.03
8 3.46
9 3.90
10 4.33
20 8.66
30 12.99
40 17.32
50 21.65
60 25.99
70 30.32
80 34.65
90 38.98
100 43.31
120 51.97
140 60.63
160 69.29
180 77.96
200 86.62
250 108.27
300 129.93
350 151.58
400 173.24
500 216.55
600 259.85
700 303.16
800 346.47
900 389.78
1000 433.0

  • water at 62oF