Static head is the total elevation change that the liquid must undergo. In most cases, static head is normally measured from the surface of the liquid in the supply vessel to the surface of the liquid in the vessel where the liquid is being delivered. The total static head is measured from supply vessel surface to delivery vessel surface, regardless of whether the pump is located above the liquid level in the suction vessel (which is referred to as a “suction lift”) or below the liquid level in the suction vessel (“suction head”). above Figure shows an example of a pump with a static suction head, and defines static suction head, static discharge head, and total static head. below Figure shows a system with a static suction lift
below Figure shows that when the discharge piping goes above the delivery vessel liquid surface, such as in the spray head shown, part of the static head that would be measured to the high point in the piping is recovered due to the siphon effect in the final downhill leg of pipe. Note that the static head to the high point of the piping in below Figure must be considered when initially filling the system, to ensure that the pump develops enough head to reach the high point of the system.
below Figure shows a submerged return line, where the reference for static head reverts back to the delivery vessel liquid surface
Note that for a pump in a closed loop system , the total static head is zero, since all of the static head from the pump to the high point in the piping system is recovered in the downhill leg of the system.