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Characteristics of Refrigerant Leaks from Small Hvac&r Systems

by Viral K Patel, Ahmed G Abuheiba, William Miller, Van D Baxter
Publication Type
Conference Paper
Journal Name
Proceedings of 25th International Congress of Refrigeration
Book Title
Proceedings of the 25th IIR International Congress of Refrigeration
Publication Date
Page Numbers
1392 to 1399
Publisher Location
Paris, France
Conference Name
25th IIR International Congress of Refrigeration
Conference Location
Montreal, Quebec, Canada
Conference Sponsor
International Institute of Refrigeration
Conference Date

Reduced use of high global warming potential (GWP) hydrofluorocarbon (HFC) refrigerants is desired. However, many lower-GWP alternatives are flammable, some of higher flammability levels, or A3, and others of lower flammability (A2 or A2L).
Safety standards for A2 and A3 flammable refrigerants, including the International Electrotechnical Commission (IEC) standard IEC 60335-2-40 calculate maximum flammable refrigerant charge limits using a fixed 4-minute leak time based on the time to leak 150 g of CO2 through a capillary tube.
Actual refrigerant leak times depend on the equipment type, leak location, leak orifice diameter and equipment operation condition (on or off).
Five systems were installed in test chambers with leak quantities and rates measured by tracking total system weight during the leak event. Among the major results were that almost all of the system charge was shown to escape the units, >80% within the first 10 minutes.