BS EN ISO 4126-3:2006

BS EN ISO 4126-3:2006 Safety devices for protection against excessive pressure. Safety valves and bursting disc safety devices in combination
BS EN ISO 4126-3 specifies the requirements for a product assembled from the in-series combination of safety valves or CSPRS (controlled safety pressure relief systems) according to BS EN ISO 4126-1, BS EN ISO 4126-4 and BS EN ISO 4126-5, and bursting disc safety devices according to BS EN ISO 4126-2 installed within no more than five pipe diameters from the valve inlet.
BS EN ISO 4126-3 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. Contents of BS EN ISO 4126-3:

Introduction
Scope
Normative references
Terms and definitions Symbols
Design of combination
Installation of combination
Combination performance
Determination of combination discharge capacity factor, Fd, by testing Derivation of combination discharge capacity factor, Fd Alternative to testing for Fd
Certification of combination discharge capacity factor, Fd
Application and use of the certified combination discharge capacity factor, Fd
Marking and identification of combination devices
Certification
Preparation for storage and transport
Requirements of EU Directive 97/23/EC (PED