BS 4504: Circular flanges for pipes, valves and fittings. (PN designated).

British Standard BS 4504 : Section 3.1 : 1989 – Circular Flanges for Pipes, Valves and Fittings (PN Designated), Specification for Steel Flanges. This covers flanges in nominal pressure ranges PN 2.5 to PN 40 and nominal sizes up to DN 4000 (see table below).BS 4504 substantially agrees with ISO 7005-1 : 1992 (E) Part 1 : Steel Flanges.

BS 4504 : 1969 is still commonly used. This older standard allows for manufacture from bar, whereas the latest standard specifies that forging or plate are to be used, which can be significantly more expensive. There are minor differences in dimensions between the two versions. The following tables are based on the later version.




BS 4504 Standard Flanges Type code, PN range and Marking Requirements
BS 4504 Standard Flanges Dimensions and Tolerances
BS 4504 Standard Flange Facings Types,Welding Ends of neck flange
BS 4504 Standard Flange Flange Facing Dimensions
BS 4504 Standard Flange Drilling Details and Dimensions.
BS 4504 Standard Code 101 Plate Flange and Dimensions
BS 4504 Standard Code 111 Weld Neck Flange and Dimensions
BS 4504 Standard Code 112 Slip On Flange and Dimensions
BS 4504 Standard Code 113 Threaded Flange
BS 4504 Standard Code 105 Blank Flange (Blind Flange)
BS 3293 Standard Welding Neck, Slip On Flange (150lb-600lb)
BS 10 Standard Table D, Table E, Table F, Table H Flange