Be careful, performance is affected by many variables. Different types of impellers have different performance, for example a radial vane (Barske) impeller will give different performance than a backswept vane impeller. Open impellers perform differently than closed, etc. If you need accurate performance data, follow
tstead's advise and test the pump. Reference the Hydraulic Institute Standards for testing information. If "typical" performance data is sufficient, start by getting the following information from the pump:
Motor Speed
Impeller Diameter (remember, it may be trimmed from it's maximum size)
Pump Casing Inlet Diameter
Pump Casing Discharge Diameter
Manufacturers Name
Pump Model Number
Note that "typically" the pump size is designated as:
(Discharge Diameter)x(Inlet Diameter) - (Max Impeller Dia)
for example 3x4-13 means a 3-inch discharge, 4-inch suction and 13-inch maximum impeller. You can get a pump curve from the manufacturer or there is a website
that has a number of manufacturers' catalog data available to check the size on line. The program is nice in that you can vary parameters and see the affect on performance. Remember that published test data is usually on 1.0 specific gravity fluid (Water) so if your process fluid specific gravity is different, you'll need to adjust the performance data. A good overall reference is the Cameron Hydraulic Data book, available from
Good Luck.