BS EN 1759-1:2004 standard for a single system of flanges specifies requirements for circular steel flanges in Class designations Class 150 to Class 2 500 and nominal sizes from NPS to NPS 24.

This standard specifies the flange types and their facings,dimensions,tolerances,threading,bolt sizes,flange jointing face surface finish,marking,materials and pressure/temperature ratings.

This standard does not apply to flanges made from bar stock by turning,or to flanges of types 11, 12, 13, 14 and 15 made from plate material.

This standard specifies the flange types and their facings,dimensions,tolerances,threading,bolt sizes,flange jointing face surface finish,marking,materials and pressure/temperature ratings.This standard does not apply to flanges made from bar stock by turning,or to flanges of types 11, 12, 13, 14 and 15 made from plate material.
Information to be supplied by the equipment manufacturer:
The following information should be supplied by the equipment manufacturer in the enquiry and/or order.Flanges and ancillary components in accordance with this standard shall be designated with the following:
a)Designation, e.g. flange, lapped or collar;
b)Number of this standard, EN 1759-1;
c) Flange type number;
d) Facing type number;
e) Nominal size (NPS or DN);
f) Class designation followed by the appropriate number;
g) The bore for weld-neck (type 11) and hubbed slip-on (type 12) flanges, if different from those specified in this standard.
h) Weld end preparation required;