Specific Speed of a Pump

The Specific Speed of a Pump is a method of describing a pump by parameters such as the speed, head and flow rate.  The Specific Speed helps in deciding the type of pump for a specific application.  It also helps in comparing different types of pumps against a single requirement.

The Specific Speed is the speed at which a geometrically similar pump would have to run to deliver a flow rate of 1 liter of fluid at a head of 1 meter.

The Specific Speed can be calculated using the following formula


where 
n is the speed in rpm
Q is the flow rate and 
h is the head in metres