Get to Know: Pump Terminology

Are you looking to buy a pump online? Industry terms can be tricky to get a grip of, especially if you’re not used to the language buying a pump online will be a difficult task. Buy Pumps Direct have put together a list of top pump industry terms for you to understand…

B.E.P.: Best Efficiency Point. The kinetic energy that a pump produces is never converted with 100% efficiency to pressure energy. There are always losses due to friction in the seals/bearings, friction of the pumped fluid over the impeller, etc. The BEP is the volumetric flow rate of the pump for which the pump was designed to convert the most kinetic energy into pressure energy.

Efficiency: the measured power out of a piece of equipment divided by the power produced by the piece of equipment. Shown as a percentage.

Flooded Suction: if the pump is below the liquid source, and the suction is fed bigravity. This is the preferred method of centrifugal pumps.

Flow: refers to the measurement of the liquid volume capacity of a pump – usually considered in litres per minute (L/min), litres per second (L/sec) and metres cubed an hour (m3/hr).

Head: a term in fluid mechanics which describes the energy stored in a fluid due to the pressure exerted on its container.

Impeller: a device that attaches to a rotating shaft and converts energy into the fluid being pumped.

Performance curve: a graph which depicts the plot of total head vs flow rate for a specific pump, with a specific impeller and set of characteristics.

Pipe Friction Loss: the loss in head due to the friction between the process fluid and the walls of the pipes and joints.

Pressure: is the ratio of a force over an area over which the force is applied. Often measured in psi or kpa.

Pressure Drop: the difference in pressure between two areas of a pump, or between the inside and outside of a container.

Specific Gravity (SG): the ratio of the density of a substance compared to the density of a reference (usually water 4ºC).

Total Head: the sum of the head produced by the pump. It can be calculated by subtracting the suction head from the discharge head. Also referred to as Total Dynamic Head.


When you’re deciding to buy a pump, it’s important you understand the technical language that you’ll come across. Use this helpful guide to make sure you’re buying the perfect pump for your needs.

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