A test standard for measuring refrigerant flow rates has been revised by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and now includes the new ozone-safe refrigerants.

ANSI/ASHRAE Standard 41.9-2000, “A Standard Calorimeter Test Method for Flow Measurement of a Volatile Refrigerant,” is used by manufacturers of compressor and condensing units to rate the performance of their products. The standard sets recommended practices for measuring the flow rate of volatile refrigerants using a calorimeter as a primary flow measuring instrument.

The standard includes terminology and specifications for conducting calorimeter tests for both azeoptropic and zeotropic refrigerants.

The standard also can be used by other equipment manufacturers, such as those of heat exchangers, to measure refrigerant flow rates, according to Richard Hall, chair of the committee that wrote the standard.