ISO 21012:2018 specifies design, construction, type and production testing, and marking requirements for non-insulated cryogenic flexible hoses used for the transfer of cryogenic fluids within the following range of operating conditions: - working temperature: from −270 °C to +65 °C; - nominal size (DN): from 10 to 100. End fittings for mounting of any couplings are within the scope of this document, but the couplings are subject to other standards. ISO 21012:2018 is intended that the hose be designed and tested to satisfy the generally accepted rated pressure i.e. at least PR 40. Hoses may be then selected with a PR equal to or greater than the maximum allowable pressure (PS) of the equipment to which it is to be used.