PREN 1268-5 : DRAFT 1996

1 Scope
2 Normative references
3 Definitions
  3.1 Controlled safety pressure relief systems
      (C.S.P.R.S.)
  3.2 Pressure
  3.3 Lift
  3.4 Flow area
  3.5 Discharge capacity
  3.6 Notified body
  3.7 Inspection authority
  3.8 Nominal size D.N.
  3.9 Functional times
4 Design, materials and construction
  4.1 General
  4.2 End connections
  4.3 Minimum requirements for springs
  4.4 Materials for controlled safety pressure relief systems
  4.5 Requirements and procedures
5 Integrity testing in works of controlled safety pressure
  relief systems
  5.1 Purpose
  5.2 General
  5.3 Hydraulic and pneumatic test
  5.4 Seat test
6 Operating and flow characteristics for controlled
  safety pressure relief systems tested on steam air,
  water or other gases or liquids of known characteristics
  6.1 General
  6.2 Tests to determine operating characteristics
  6.3 Test to determine flow characteristics
  6.4 Records and test results
  6.5 Certification of controlled safety pressure relief
      system
7 Determination of controlled safety pressure relief
  system performance
  7.1 Determination of coefficient of discharge
  7.2 Critical and sub-critical flow
  7.3 Discharge capacity at critical flow
  7.4 Discharge capacity of any gas at sub-critical flow
  7.5 Discharge capacity using liquid as the test medium
      in the turbulent zone where the Re <= 80 000.
8 Sizing of main valves
  8.1 Valves for gas or vapour relief
  8.2 Calculation of capacity
9 Marking and sealing
  9.1 Marking on the body of the main valve
  9.2 Marking on an identification plate
  9.3 Sealing of a controlled safety pressure relief system

Specifies the requirements for controlled safety pressure relief systems irrespective of the fluid for which they are designed.