Static suction head of centrifugal pump

Head is a term used to express pressure in both pump design and system design when analyzing static or dynamic conditions. This relationship is expressed as:

head in feet = (pressure in psi x 2.31) / specific gravity

Pressure in static systems is referred to as static head and in a dynamic system as dynamic head


Total static head is the vertical distance between the surface of the suction source liquid and the surface level of the discharge liquid. Static discharge head is the vertical distance from the centerline of the suction nozzle up to the surface level of the discharge liquid.

Static suction head applies when the supply is above the pump. It is the vertical distance from the centerline of the suction nozzle up to the liquid surface of the suction supply. Static suction lift applies when the supply is located below the pump. It is the vertical distance from the centerline of the suction nozzle down to the surface of the suction supply liquid. Velocity, friction, and pressure head are used in conjunction with static heads to define dynamic heads.

Velocity head is the energy in a liquid as a result of it traveling at some velocity V. It can be thought of as the vertical distance a liquid would need to fall to gain the same velocity as a liquid traveling in a pipe.

This relationship is expressed as: hv = V2/2g

where V = velocity of the liquid in feet per second and
g = 32.2 ft/sec2.