The pump specific speed is a method of characterizing pump conditions and can be used to determine the pump design most suitable for a given application. Often, pump characteristics such as NPSHr, pump suction elevator and pump efficiency will be related to the pump specific speed.

The speed of the pump is one of the triumphant amounts that constitute the fundamental relationship that governs the behavior of all vacuum systems. This relationship, written as Q (gas charge) S (pump speed) x P (pressure), must be constantly at the forefront of the thinking of each vacuum technologist.

The specific speed is an index used to predict the desired performance of the pump or turbine. In other words, it offers the overall shape of a pump pusher. It is the shape of the pusher that offers its flow and head characteristics, so that the designer can then select a pump or turbine more suitable for a given application.

The specific speed is defined as the speed of a geometrical ideal pump similar to the real pump, which, depending on this speed, will increase a volume unit, in a unit of time through a head unit. Revenge of a centrifugal pump is expressed in terms of pump speed, total head and required flow.

The specific speed is an index used to predict the desired performance of the pump or turbine, i.e. predict the overall shape of a turbine. It is this form of turbine that provides its flow and head characteristics so that the designer can then choose a pump or turbine that best suits a particular application.