ISO 4126-4:2013 specifies general requirements for pilot operated safety valves, irrespective of the fluid for which they are designed. In all cases, the operation is carried out by the fluid in the system to be protected. It is applicable to pilot operated safety valves having a valve flow diameter of 4 mm and above which are for use at set pressures of 0,1 bar gauge and above. No limitation is placed on temperature. ISO 4126-4:2013 is a product standard and it is not applicable to applications of pilot operated safety valves.
Tämän julkaisun valmistelusta Suomessa vastaa Metalliteollisuuden Standardisointiyhdistys ry, puh. 09 19 231 (vaihde).
Sisällysluettelo
Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and units
5 Design
5.1 General
5.2 Valve end connections
5.3 Minimum requirements for springs
5.4 Materials
6 Production testing
6.1 Purpose
6.2 General
6.3 Hydrostatic testing
6.4 Pneumatic testing
6.5 Adjustment of set or cold differential test pressure
6.6 Seat leakage test
6.7 Pressure seals
7 Type testing
7.1 General
7.2 Tests to determine operating characteristics
7.3 Tests to determine flow characteristics
7.4 Determination of the coefficient of discharge
7.5 Certification of coefficient of discharge
8 Determination of pilot operated safety valve performance