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
pb   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 DIN EN ISO 17769-1, for example. See Fig. 1 Specific energy

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