Total head

The total head HBN, calculated from a datum level BN, is the mechanical energy of the fluid handled, per unit weight. The unit of total head is metres (m).

z     Geodetic height of given point above BN
p_b   Atmospheric pressure
p     Overpressure (positive) or underpressure (negative) in relation to pb
ρ     Density of fluid handled
g     Gravitational acceleration
v      Flow velocity

A graphic representation of the total head at various points within a pump system can be found in EN 12723, for example. See Fig. 1 Specific energy