BS 4504-3.3:1989 pdf free download.Circular flanges for pipes, valves and fittings (PN designated). Specification for copper alloy and composite flanges.
1 Scope
This Section of BS 4504 specifies requirements for PN designated circular copper alloy and composlte flanges in the ranges of nominal pressure PN 6 to PN 40 and in nominal sizeS up to DN 1 800 of the types given in Table 1.
This Section of BS 4504 specifies the types of flanges and their facings, dimensions, tolerances, bolt sizes flange face suface finish. manking materials for bolting and flange materials together with associated pressure/temperature ratings.
NOTE 1: Details of tube stops used in conjunction with code 314 flanges are outside the scope of this standard.
NOTE 2: To assist purchasers appendix A lists information which should be supplied when ordering flanges.
NOTE 3: The routine inspection and pressure testing are outside the scope of this standard but some guidance is given in appendix B
NOTE 4: The titles of the standards refered to in this standard are isted on the inside back cover.
4.3 Rating of flanged joints
If two flanges in flanged joint do not have the same oressure/temperature rating, the maximum
permissible working pressure of the joint at any temperature shall not exceed the lower of the two
pressure ratings.
5 Materials
Copper alloy components of flanges shall be manufactured from the materials given in Table 3 and steel components of flanges shall be manufactured from the materials given in Table 4
NOTE 1 Where there is an appropriate application standard it the responsibility of the purchaser to ensure that the requirements of that standard are met.
NOTE 2 If a protective coating such as zinc coating or painting on steel components is required,
the purchaser should state the requirements on the enquiry and/or order(see appendix A).