BS 3293:1960

Foreword
Specification
Section One: General
1. Scope
2. Designation and pressure/temperature ratings
3. Flange facings
4. Nominal sizes
Section Two: Materials
5. Materials for flanges
6. Bolting materials
Section Three: Dimensions and Tolerances
7. Flanges
8. Flange facings and gaskets
9. Flange bolting dimensions
10. Spot-facing and back-facing of flanges
Section Four: Inspection
11. Inspection
12. Repair of defects
Section Five: Marking
13. Marking
Section Six: Preparation and Despatch
14. Preparation
15. Despatch
Tables
1. Dimensions of flanges, Class 150
2. Drilling, bolting and facing dimensions for flanges.
    Class 150
3. Dimensions of flanges, Class 300
4. Drilling, bolting and facing dimensions for flanges,
    Class 300
5. Dimensions of flanges, Class 400
6. Drilling, bolting and facing dimensions for flanges,
    Class 400
7. Dimensions of flanges, Class 600
8. Drilling, bolting and facing dimensions for flanges,
    Class 600
9. Dimensions of compressed asbestos fibre gaskets
10. Numbers and dimensions of ring-joint gaskets for
    Class 300, 400 and 600 flanges

Specifies materials, dimensions and marking for forged carbon steel slip-on welding and welding neck flanges, of nominal size 26 in to 48 in for Classes 150, 300, 400 and 600.

This British Standard is a material and dimensional standard only and applies to forged carbon steel slip-on and welding neck flanges of nominal sizes 26 in and larger, for use in the petroleum industry. Drilling, bolting, facing and thickness dimensions are applicable also to integral end flanges of valve and fittings.

Four classes of flanges are provided for, namely Classes 150, 300, 400 and 600.

The standard does not include pressure/temperature ratings; the flange designations quoted are for identification purposes only.