LP gas cylinder capacity below 5000 litres

73.11 - Containers for compressed or liquefied gas, of iron or steel. This heading covers containers of any capacity used for the transport or storage of compressed or liquefied gases (e.g., helium, oxygen, argon, hydrogen, acetylene, carbon dioxide or butane). Some are strong cylinders, tubes, bottles, etc., tested at high pressure; these may be weldless or welded (e.g., at the bases, round the middle or along the length). Others consist of an inner vessel and one or more outer shells, the intervening space being packed with insulating material, maintained under vacuum or arranged to contain a cryogmc fluid, thus enabling certain liquefied gases to be kept at atmospheric pressure or low pressure. These containers may be fitted with control, regulating and measuring devices such as valves, taps, pressure gauges, level indicators, etc. Some (e.g.,. for acetylene) contain an inert porous substance such as kieselguhr, charcoal or asbestos, with a binder such as cement and sometimes impregnated with acetone, to facilitate filling and to prevent the risk of explosion if acetylene were compressed alone. In others, such as those desi ed to su ply liquid or gas as required, the liquefied gas is vapourised solely under the in uence of !it e atmospheric temperature, by passing through a coil attached to the inner wall of the outer shell. W" The heading excludes steam accumulators (heading 84.04).