is the height of a column of fluid that will produce a given pressure: h =: p/w where h is the height of the column of fluid p is the pressure generated by the head w is the specific weight of the fluid A column of water 28" high will produce a pressure of 1 PSI.

The operating pressure in feet of head required at the sprinkler head.

Pressure in a plumbing system. The unit of measure which is the vertical force exerted by water at a depth of one foot.

The specific energy of pressure (equal to p/g ).

The pressure energy necessary at the distribution water system entrance to overcome losses and operate various irrigation equipment/emitters at the designed pressure.