ISO/TC 220/WG 3 - Supporting standards

This document defines practical methods for determining the heat-leak performance of cryogenic vessels. The methods include measurement on both open and closed systems. This document neither specifies the requirement levels for insulation performance nor when the defined methods are applied.

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.

ISO 21013-3:2016 provides separate calculation methods for determining the required mass flow to be relieved for each of the following specified conditions: - vacuum-insulated vessels with insulation system (outer jacket + insulating material) intact under normal vacuum, outer jacket at ambient temperature, inner vessel at temperature of the contents at the specified relieving pressure; - vacuum-insulated vessels with insulation system (outer jacket + insulating material) intact under normal vacuum, outer jacket at ambient temperature, inner vessel at temperature of the contents at the specified relieving pressure, pressure regulator of the pressure build-up system functioning at full potential; - vacuum or non-vacuum-insulated vessels with insulation system remaining in place, but with loss of vacuum in the case of vacuum-insulated vessels, outer jacket at ambient temperature, inner vessel at temperature of the contents at the specified relieving pressure or vacuum or non-vacuum-insulated vessels with insulation system remaining fully or partially in place, but with loss of vacuum in the case of vacuum-insulated vessels, fire engulfment, inner vessel at temperature of the contents at the specified relieving pressure; - vacuum-insulated vessels containing fluids with saturation temperature below 75 K at 1 bar with insulation system remaining in place, but with loss of vacuum with air or nitrogen in the vacuum space; - vacuum insulated vessels containing fluids with saturation temperature below 75 K at 1 bar with insulation system remaining in place, but with loss of vacuum with air or nitrogen in the vacuum space with fire engulfment; - vessels with insulation system totally lost and fire engulfment. Good engineering practice based on well-established theoretical physical science needs to be adopted to determine the required mass flow where an appropriate calculation method is not provided for an applicable condition. Recommendations for pressure relief devices for cryostats are given in Annex A.

ISO 21013 specifies the requirements for the design, manufacture and testing of pressure relief valves for cryogenic service, i.e. for operation with cryogenic fluids in addition to operation at temperatures from ambient to cryogenic. It is a requirement of ISO 21013 that the valves comply with ISO 4126-1; in the event of different requirements, ISO 21013 takes precedence. ISO 21013 is restricted to valves not exceeding a size of DN 150 designed to relieve single-phase vapours or gases. A valve may be specified, constructed and tested such that it is suitable for use with more than one gas or with mixtures of gases. ISO 21013-1:2008 does not provide methods for determining the capacity of relief valve(s) for a particular cryogenic vessel. Such methods are provided in ISO 21013-3.

ISO 21011:2008 specifies the requirements for the design, manufacture and testing of valves for a rated temperature of -40 °C and below (cryogenic service), i.e. for operation with cryogenic fluids in addition to operation at temperatures from ambient to cryogenic. ISO 21011:2008 applies to all types of cryogenic valves, including vacuum jacketed cryogenic valves up to size DN 150. ISO 21011:2008 is not applicable to pressure relief valves covered by ISO 21013-1.

ISO 21013-2:2007 specifies the requirements for the design, manufacture and testing of non‑reclosable pressure‑relief devices for cryogenic service, i.e. for operation with cryogenic fluids in addition to operation at temperatures from ambient to cryogenic. ISO 21013-2:2007 is restricted to bursting‑disc and buckling‑pin devices not exceeding a size of DN 200 designed to relieve single‑phase vapours or gases. A bursting‑disc or buckling‑pin assembly may be specified, constructed and tested such that it is suitable for use with more than one gas or with mixtures of gases. ISO 21013-2:2007 does not provide methods for determining the capacity of bursting disc or buckling pin devices for a particular cryogenic vessel. Such methods are provided in ISO 21013-3.

ISO 21012:2006 gives 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 minus 270 °C to minus 65 °C; nominal size (DN): from 10 to 100. End fittings for mounting of any couplings are within the scope of this International Standard, but the couplings are subject to other standards.

ISO 21014:2006 defines practical methods for determining the heat-leak performance of cryogenic vessels. The methods include measurement on both open and closed systems. ISO 21014:2006 neither specifies the requirement levels for insulation performance nor when the defined methods should be applied. These requirements may be defined in design or operational standards/regulations.

ISO 21013-3:2006 provides separate calculation methods for determining the required mass flow to be relieved for each of the following specified conditions. Vacuum-insulated vessels with insulation system (outer jacket + insulating material) intact under normal vacuum; outer jacket at ambient temperature; inner vessel at temperature of the contents at the relieving pressure. Vacuum-insulated vessels with insulation system (outer jacket + insulating material) intact under normal vacuum; outer jacket at ambient temperature; inner vessel at temperature of the contents at the relieving pressure; pressure regulator of the pressure build-up system functioning at full potential. Vacuum-insulated vessels with insulation system remaining in place but with loss of vacuum, or non-vacuum-insulated vessels with insulation system intact; outer jacket at ambient temperature; inner vessel at temperature of the contents at the relieving pressure; vacuum or non-vacuum-insulated vessels with insulation system remaining fully or partially in place, but with loss of vacuum in the case of vacuum-insulated vessels, and fire engulfment; inner vessel at temperature of the contents at the relieving pressure. Vessels with insulation system totally lost and fire engulfment. Good engineering practice based on well-established theoretical physical science needs to be adopted to determine the required mass flow where an appropriate calculation method is not provided for an applicable condition.