property of a liquid expressed as the ratio of the liquid’s density to that of water at standard temperature
NOTE Standard temperature is 4 °C (39,2 °F).
6.3 Pressure casings
6.3.1 The maximum discharge pressure shall be the maximum suction pressure plus the maximum differential
pressure that the pump is able to develop when operating with the furnished impeller at the rated speed and
specified normal relative density (specific gravity).