| Definition: | This material class includes gases and liquids:
- used in the refrigeration cycle;
- (liquids) that boil at a temperature below about 110 Kelvin (-160°C) and are used to obtain very low temperatures; and
- (Greenhouse Gases (GHG)) that contribute to the greenhouse effect by absorbing infrared radiation, such as carbon dioxide, chlorofluorocarbons, SF6 and other gases with a high greenhouse gas potential. |