Converting Pump Head to Pressure

[Esam]

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

[Esam]

[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 62^oF