# Head Pressure

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Head pressure, also called static head or static head pressure, is the pressure at a specific point to the vertical distance at another specific point.  The pressure is effected by gravity and height.  The pressure exerted at top of the liquid column is less than the pressure exerted on the base of the column, so where you place the gauge will effect the reading of the head pressure.

## Head Pressure formulas

 $$\large{ p = \frac { h \; SG } { 2.31 } }$$ $$\large{ h = \frac { 2.31 \; p } { SG } }$$

### Where:

 Units English Metric $$\large{ p }$$ = pressure $$\large{\frac{lbf}{in^2}}$$ $$\large{Pa}$$ $$\large{ h }$$ = head or height $$\large{ft}$$ $$\large{m}$$ $$\large{ SG }$$ = specific gravity $$\large{dimensionless}$$ $$\large{ 2.31 }$$ = conversion factor (2.31 feet of fresh water = 1 psi) - -