By now, you may have a basic familiarity with the performance curve (H-Q) of the centrifugal pump. While it looks like the pump can be used for the entirety of the curve, each individual pump model has a design duty. This design point is generally where the pump has the highest hydraulic efficiency, also known as the best efficiency point (BEP). While it is rare for the desired duty to fall exactly on the BEP of the pump, we can make sure the pump is most suited for the application by making sure we choose a pump whose BEP is close to the desired pump duty. The recommended range is between 70% to 120% of the flow capacity of the BEP. Running a pump too far outside the recommended range would have some negative effects, such as low energy efficiency, reduced service life from parts wear, overheating of the pump, or a higher risk of cavitation to name a few.