Freons are responsible for the formation of the ozone hole.
The Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol are international agreements that oblige signatory countries to limit the emission of ozone-depleting gases.
According to ASHRAE standard 34, the R-number of a chemical refrigerant is assigned systematically according to its molecular structure and has between two and four digits.
This basic scheme is modified as follows: There are separate numbering schemes for zeotropic and azeotropic blends, organic chemicals which don't fit into the scheme above, and inorganic chemicals: The table is sortable by each of the following refrigerant properties (scroll right or reduce magnification to view more properties): Since over 100,000 refrigerant blends are possible,[2] this list should only have notable refrigerants and refrigerant blends.
LFL = Lower Flammability Limit ETFL60 = Elevated Temperature Flame Limit @ 60 °C HOC = Heat Of Combustion Compounds used as refrigerants may be described using either the appropriate prefix above or with the prefixes "R-" or "Refrigerant."