This International Standard specifies the minimum requirements for the cleanliness of all surfaces of cryogenic vessels and associated accessories that are in contact with the cryogenic fluid at any expected operating conditions. This International Standard defines the acceptable level of surface and particle contamination to minimize the risk of malfunction of equipment and ensure safety against ignition when in contact with oxygen or oxidizing fluids (see ISO 10156-2).
GSO ISO 23208:2016 history
2016GSO ISO 23208:2016 Cryogenic vessels -- Cleanliness for cryogenic service