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.