water storage tank pressure

[jchealey]

I would like to install a water storage tank to be used mainly for fire suppression since we don't have any hydrants in our area. What is the formula for the pressure coming out of the tank based on height of the tank and amount of water in the tank? Since I most likely can't get the tank high enough, what kind of fire pump would you recommend?

Jerry

[LazyPup]

The formula you are looking for is "Vertical Static Head"

Vertical Static Head pressure is techically the physical weight of the water standing in a vertical column and is expressed in PSI (pounds per square inch).

A one square inch vertical column of water will exert .433 pounds pressure at the base for each foot of vertical elevation so we can then define that it requires 2.39ft of veritcal column to produce 1 PSI.

Keep in mind that we are measuring the downward force on a one square inch footprint on the base of a water column therefore the diameter of a pipe or tank has no bearing on the pressure at the base. If we were to stand a pipe vertically along the side of a large tank and fill both the pipe and the tank to the same vertical level, the pressure at the base will be equal.