BS ISO 21013-1:2008

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
   4.1 General
   4.2 Design
        4.2.1 Design temperature
        4.2.2 Drainage
        4.2.3 Stem guiding
        4.2.4 Inserts
        4.2.5 Sublimating fluids service
        4.2.6 Electric continuity
        4.2.7 Set pressure
        4.2.8 Minimum shell thickness
   4.3 Materials
        4.3.1 General
        4.3.2 Metallic materials
        4.3.3 Non-metallic materials
        4.3.4 Corrosion resistance
        4.3.5 Gas material compatibility
        4.3.6 Acetylene compatibility
5 Qualification and Testing
   5.1 Type approval
        5.1.1 Verification of the design
        5.1.2 Model number
   5.2 Type approval tests
        5.2.1 Ambient condition tests
        5.2.2 Cryogenic tests
        5.2.3 Alternate cryogenic tests
   5.3 Production testing
6 Determination of the certified coefficient of discharge (K[dr])
7 Set pressure tolerances
8 Re-seating pressure
9 Cleanliness
10 Marking
   10.1 Marking on the body of the pressure-relief valve
   10.2 Marking on an identification plate
11 Sealing
Bibliography

Describes 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.

This International Standard 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 this International Standard that the valves comply with ISO4126-1; in the event of different requirements, this International Standard takes precedence.

This International Standard 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.

NOTE This part of ISO21013 does not provide methods for determining the capacity of relief valve(s) for a particular cryogenic vessel. Such methods are provided in ISO21013-3.