PREN 1268-1 : DRAFT 1994

1 Scope
2 Normative references
3 Definitions
  3.1 Safety valve
  3.2 Pressure
  3.3 Lift
  3.4 Flow area
  3.5 Flow diameter
  3.6 Discharge capacity
  3.7 Notified body
  3.8 Inspection authority
  3.9 Nominal size
4 Design, materials and construction
  4.1 General
  4.2 End connections
  4.3 Materials
5 Integrity testing in the factory
  5.1 Purpose
  5.2 General
  5.3 Hydraulic test
  5.4 Pneumatic testing
  5.5 Adjustment of cold differential test pressure
  5.6 Seat leakage test
6 Operating and flow characteristic tests
  6.1 General
  6.2 Operating characteristics
  6.3 Flow characteristics
  6.4 Determination of coefficient of discharge
  6.5 Certification of valves
7 Determination of safety valve performance
  7.1 Determination of coefficient of discharge K[d]
  7.2 Critical and subcritical flow
  7.3 Discharge capacity at critical flow
  7.4 Discharge capacity for any gas at subcritical flow
  7.5 Discharge capacity for liquid
8 Sizing of safety valves
  8.1 Valves for gas and vapour
  8.2 Calculation of capacity
9 Marking and sealing
  9.1 Marking on the body of a safety valve
  9.2 Marking on an identification plate
  9.3 Sealing of a safety valve