How Maximum Suction Lift Changes with Altitude and Atmospheric Pressure for an End-Suction Pump

MountainThe maximum vertical distance an end-suction pump can “suck” water is determined by two parameters: the altitude at which the pump is situated (and therefore the atmospheric pressure) and the design of the pump.

Since end-suction pumps, don’t actually suck the water up the hose (they create a vacuum and rely on atmospheric pressure to “push” the water up), the maximum suction lift is determined by the pump’s altitude. Generally speaking, the closer to sea level the more suction lift is available and the easier the pump is to prime.

The table below shows the theoretical limit and a more realistic maximum for maximum suction lift.

Altitude (m) Atmospheric Pressure (kg/cm2) Theoretical Max. Suction Lift (m) Realistic Max. Suction Lift (m)
0 (Sea Level) 1.03 10.33 7.52
100 1.02 10.21 7.40
200 1.01 10.09 7.28
300 1.00 9.97 7.16
400 0.99 9.85 7.04
500 0.97 9.73 6.92
600 0.96 9.62 6.81
636 (Kinder Scout) 0.96 9.58 6.76
700 0.95 9.50 6.69
800 0.94 9.39 6.58
900 0.93 9.28 6.46
978 (Scafell Pike) 0.92 9.19 6.38
1000 0.92 9.17 6.35
1344 (Ben Nevis) 0.88 8.79 5.98
2000 0.81 8.11 5.29
3000 0.71 7.15 4.34
4000 0.63 6.29 3.47
4810 (Mont Blanc) 0.57 5.65 2.84
5000 0.55 5.51 2.70