ISO 20421-1:2006 specifies requirements for the design, fabrication, inspection and testing of large transportable vacuum insulated cryogenic vessels of more than 450 l volume, which are permanently (fixed tanks) or not permanently (demountable tanks and portable tanks) attached to a means of transport, for one or more modes of transport.

ISO 20421-1:2006 applies to large transportable vacuum insulated cryogenic vessels for cryogenic fluids, and does not apply to vessels designed for toxic fluids.

ISO 20421-1:2006 does not include the general vehicle requirements, e.g. running gear, brakes, lighting, etc., which are in accordance with the relevant standards/regulations.