Any material or mixture that, when enclosed in a container, has an absolute pressure exceeding 40 psi at 21.1 C or, regardless of the pressure at 21.1 C, has an absolute pressure greater than 104 psi(a) at 54.4 C, or any flammable material having a vapor pressure greater than 40 psi abs at 37.7 C (vapor pressure determined by Reid method (ASTM)). Compressed gases include liquefied petroleum gases and oxygen, nitrogen, anhydrous ammonia, acetylene, nitrous oxide, and fluorocarbon gases. Some of these are shipped in tonnage volume. For details on properties, containers, and shipping regulations, see the entries for specific gases.