Centrifugal Pump Characteristic Curves
For a given centrifugal pump operating at a constant speed, the flow rate through the pump is
dependent upon the differential pressure or head developed by the pump. The lower the pump
head, the higher the flow rate. A vendor manual for a specific pump usually contains a curve
of pump flow rate versus pump head called a pump characteristic curve. After a pump is
installed in a system, it is usually tested to ensure that the flow rate and head of the pump are
within the required specifications. A typical centrifugal pump characteristic curve is shown in
Figure 11.
There are several terms associated with the pump characteristic curve that must be defined.
Shutoff head is the maximum head that can be developed by a centrifugal pump operating at a
set speed. Pump runout is the maximum flow that can be developed by a centrifugal pump
without damaging the pump. Centrifugal pumps must be designed and operated to be protected
from the conditions of pump runout or operating at shutoff head. Additional information may
be found in the handbook on Thermodynamics, Heat Transfer, and Fluid Flow.
