PREN 13648-1 : DRAFT 1999

Foreword
1 Scope
2 Normative references
3 Definitions and symbols
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 5
      4.2.5 Sublimating cryogens
  4.3 Materials
      4.3.1 Metallic materials
      4.3.2 Corrosion resistance
      4.3.3 Oxygen compatibility
      4.3.4 Acetylene compatibility
      4.3.5 Non-metallic materials
5 Testing
  5.1 Production testing
  5.2 Sample valve test
      5.2.1 Operating and flow characteristics test
      5.2.2 Test of the repeatability of leak tightness at
            re-seat
      5.2.3 Cryogenic tests
6 Determination of the certified derated coefficient of
  discharge (K[dr])
7 Cleanliness
8 Marking
9 Sealing
Annex ZA (informative) Clauses of this European Standard
         addressing essential requirements or other
         provisions of EU directives

Specifies the requirements for the design, manufacture and testing of safety valves for cryogenic service, that is, for operation with cryogenic fluids below -10 degree C in addition to operation at ambient temperature.