ISO International Standard

ISO 8426:2008 specifies the methods of determining the derived capacity of hydraulic fluid power positive displacement pumps and motors under steady-state conditions and at defined, continuous shaft rotational frequencies.

Units can be tested as a positive displacement pump, with mechanical energy applied to the shaft and hydraulic energy obtained at the outlet fluid connection, or as a motor, with hydraulic energy supplied to the inlet fluid connection and mechanical energy obtained at the shaft.