GB/T 46630-2025 Safety valves for cryogenic vessels
Warning: This document does not purport to address all of the safety issues, if any, associated with the production and application of safety valves for cryogenic vessels. Before using this document, users are responsible for establishing appropriate safety, health and protection practices, clarifying its scope of application, and ensuring compliance with relevant national laws, regulations, and mandatory national standards.
1 Scope
This document specifies the technical requirements, tests and inspections, marking and lead sealing of spring direct-loaded safety valves for cryogenic vessels (hereinafter referred to as “safety valves”).
This document is applicable to safety valves not exceeding a size of DN 150 designed to relieve cryogenic gas medium, with medium temperature below -10℃ and operation temperatures from medium temperature to ambient temperatures. A safety valve can be designed, constructed and tested such that it is suitable for use with various single-phase gases or with mixtures of gases.
Note: This document does not provide methods for determining the discharge volume of safety valve for a particular cryogenic vessel. Such methods are provided in ISO 21013-3.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 12224 General requirements for industrial steel valves
GB/T 12241-2021 Safety valves - General requirements (ISO 4126-1:2013, MOD)
Note: There are no technical differences between the referenced content from GB/T 12241-2021 and that from ISO 4126-1:2013.
GB/T 12243 Spring loaded safety valves
GB/T 21465 Terminology for valves
GB/T 28776 Steel gate, globe and check valve for the petroleum and natural gas industries (for sizes DN 100 and smaller) (GB/T 28776-2012, ISO 15761:2002, MOD)
GB/T 29026 Spring loaded safety valve for cryogenic service
GB/T 31481 Guidance for gas/materials compatibility of cryogenic vessels (GB/T 31481-2015, ISO 21010:2014, IDT)
ISO 11114-1 Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 1: Metallic materials
ISO 11114-2 Gas cylinders - Compatibility of cylinder and valve materials with gas contents - Part 2: Non-metallic materials
ISO 21028-1 Cryogenic vessels - Toughness requirements for materials at cryogenic temperature - Part 1: Temperatures below -80℃
ISO 21028-2 Cryogenic vessels - Toughness requirements for materials at cryogenic temperature - Part 2: Temperatures between -80℃ and -20℃
ISO 23208 Cryogenic vessels - Cleanliness for cryogenic service
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 12241-2021 and GB/T 21465 as well as the following apply.
3.1
rated minimum temperature
minimum service temperature for which the safety valve is rated by the manufacturer
3.2
category A valve
safety valve that need to be frequently opened during normal operation of cryogenic vessel
Note: The procedure for the seat-tightness test is described in 5.2.1.2.
3.3
category B valve
safety valve that do not need to be opened during normal operation due to the provision of an alternative relieving or control device, e.g. a pressure regulating vent valve designed for frequent operation
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Technical requirements
5 Test methods
6 Marking
7 Sealing
Annex A (Informative) Comparison of clause/subclause numbers
Annex B (Informative) Non-toxic gases, refrigerated liquid
Bibliography
