This standard applies to the measurement of the flow of a volatile refrigerant in the following cases: a. where the entire flow stream of the volatile refrigerant enters the calorimeter as a subcooled liquid and leaves as a superheated vapor (evaporator-type)@ and b. where the entire flow stream of the volatile refrigerant enters the calorimeter as a superheated vapor and leaves as a subcooled liquid (condenser-type). This standard applies to all of the refrigerants listed in ANSI/ASHRAE Standard 34@ Designation and Safety Classification of Refrigerants.1 PURPOSE This standard provides recommended practices for measuring the mass flow rate of volatile refrigerants using calorimeters.