3.3 Compensate for Elevation


What happens to water pressure in a pipe as it goes up and down in elevation while crossing the terrain? Elevation Change illustrates these examples of the effect of elevation on water pressure. 11`

Given a water source at 80 psi, what is the pressure in a pipe downhill 50 feet lower than the source? Click on the Elevation Change diagram and adjust the window so you can read this text.

The water is initially at 80 psi and a 50-foot column of water is added under it. At the lower point, the static pressure is 80 psi plus 50 x 0.433 or 80 + 21.7 or 101.7 psi pressure.

Reversing the example, place the source 50 feet lower than the demand point.

In this case, the 50-foot column of water is acting downward against the source. At the point of demand, the static pressure is 80 psi minus 21.7 psi or 58.3 psi. The weight of water in the pipe works with or against the source pressure.