EN ISO 4126-3:2006

Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols
5 Design of combination
6 Installation of combination
7 Combination performance
8 Determination of combination discharge capacity
   factor, F[d], by testing
9 Derivation of combination discharge capacity factor,
   F[d]
10 Alternative to testing for F[d]
11 Certification of combination discharge capacity
   factor, F[d]
12 Application and use of the certified combination
   discharge capacity factor, F[d]
13 Marking and identification of combination devices
14 Certification
15 Preparation for storage and transport
Annex ZA (informative) - Relationship between this
         International Standard and the Essential
         Requirements of EU Directive 97/23/EC (PED)

ISO 4126-3:2006 specifies the requirements for a product assembled from the in-series combination of safety valves or CSPRS (controlled safety pressure relief systems) according to ISO 4126-1, ISO 4126-4 and ISO 4126-5, and bursting disc safety devices according to ISO 4126-2 installed within no more than five pipe diameters from the valve inlet. It specifies the design, application and marking requirements for such products, which are used to protect pressure vessels, piping or other enclosures from excessive pressure, and which comprise the bursting disc safety device, a safety valve or CSPRS and, where applicable, a short length of connecting pipe or spool piece. In addition, it gives a method for establishing the combination discharge factor used in sizing combinations.