ISO 21013-1:2021

This document specifies the requirements for the design, manufacture and testing of pressure relief valves for cryogenic service, i.e. for operation with cryogenic fluids below −10 °C in addition to operation at ambient temperatures from ambient to cryogenic.
This document is applicable to valves not exceeding a size of DN 150 designed to relievesingle-phase vapours or gases. A valve can be specified, constructed and tested such that it is suitable for use with more than one gas or with mixtures of gases.
NOTE       This document 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.