ISO 20421 is a series on cryogenic vessels. Cryogenic vessels are double-walled cylindrical tanks with inner stainless steel and outer carbon steel sections painted with anti-corrosion primer and filled with an insulating material. ISO 20421‑1 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 applies to large transportable vacuum-insulated cryogenic vessels for fluids.
Note 1: ISO 20421‑1 does not apply to vessels designed for toxic fluids.
Note 2: ISO 20421‑1 does not include the general vehicle requirements, e.g., running gear, brakes, lighting, etc.
Note 3: ISO 20421‑1 does not cover specific requirements for refillable liquid-hydrogen tanks that are primarily dedicated as fuel tanks in vehicles.
Note 4: ISO 20421‑1 does not cover specific requirements for refillable liquid hydrogen and LNG tanks that are primarily dedicated as fuel tanks in vehicles.
ISO 20421‑1 on cryogenic vessels is useful for:
Cryogenic vessels are evacuated to a high vacuum to achieve minimum evaporation losses. ISO 20421‑1 introduces cryogenic vessels that are large transportable cryogenic vessels that safely withstand the mechanical and thermal loads and the chemical effects encountered during pressure tests and normal operation. Large transportable cryogenic vessels are equipped with valves, pressure-relief devices, etc., configured and installed in such a way that the vessel can be operated safely. The number of openings in the inner vessel for this equipment is kept to a minimum.
The large transportable cryogenic vessel resists the mechanical loads without such deformation which can affect safety, and which can lead to leakage. This requirement can be validated by the calculation, the calculation and pressure-strengthening method is allowed and the calculation and experimental method.
The manufacturer can retain the documents referred to ISO 20421‑1, and all supporting documentation (including that from his subcontractors, if any), for a required period (e.g., product liability). In addition, the manufacturer can retain all supporting and background documentation (including that from his subcontractors, if any) which establishes that the vessel conforms to ISO 20421‑1. Using ISO 20421‑1 you can specify requirements for the design, fabrication, inspection and testing of large transportable vacuum-insulated cryogenic vessels of more than 450 l volume.
BS ISO 20421‑1:2019 supersedes BS ISO 20421‑1:2006. BS ISO 20421‑1:2019 includes some technical changes with respect to BS ISO 20421‑1:2006. These include: