Bottled gas

In the last case the bottle is constructed with an inner and outer shell separated by a vacuum (dewar flask) so that the low temperature can be maintained by evaporative cooling.

Examples include:[citation needed] The general rule is that one unit volume of liquid will expand to approximately 800 unit volumes of gas at standard temperature and pressure with some variation due to intermolecular force and molecule size compared to an ideal gas.

In the United States, the Compressed Gas Association (CGA) sells a number of booklets and pamphlets on safe handling and use of bottled gases.

The United Kingdom and other parts of Europe more commonly refer to 'bottled gas' when discussing any usage whether industrial, medical or liquefied petroleum.

The requirements are based on a combination of a few named gases, otherwise on the primary hazard associated with the gas contents: Diving cylinders are left unpainted (for aluminium), or painted to prevent corrosion (for steel), often in bright colors, most often fluorescent yellow, to increase visibility.