Flange Specification, BSI
The BSI specifications for flanges are:
- BS 10 - Specification for Flanges and Bolting for Pipes, Valves, and Fittings
- BS 3293 - Specification for Carbon Steel Pipe Flanges (over 24 inches nominal size) for the Petroleum Industry
- BS 4504 - Specification for Steel Flanges Circular Flanges for Pipes, Valves and Fittings
- ISO 7005-1 - Metallic Flanges - Part 1: Steel Flanges (this is substantially the same as BS 4504)
BSI Flange Materials
Standards usually specify the material from which the flange is produced.
BSI Flange Sizes
There are available flange sizes and grades for all standard pipe wall thicknesses and pressure ratings.
BSI Flange Facing Types
The typical flange faces used are flat face, raised face, tongue and groove and ring joint.
BSI Flange Finish
The flange face finish is determined by the standard used and measured as an Arithmetical Average Roughness Height (AARH). An example would be ANSI B16.5 which specifies face finishes within a range 125AARH - 500AARH (3.2 Ra to 12.5 Ra).
BSI Flange Class Rating
| Flange
Type | BS4504
(ISO 7005-1) DN 10 to DN 4000 | BS2393
26"-60" |
|---|---|---|
| Blind | 2.5-40 | - |
| Lap Joint | 6-40 | - |
| Slip-On | 2.5-40 | 150-600 |
| Socket | - | - |
| Threaded | 6-40 | - |
| Weld Neck | 2.5-40 | 150-600 |
| Flat/Raised Facing | As Above | As Above |
| Ring Joint Facing | 2.5-40 | 300-600 |
| Other Facings | 2.5-40 | - |
Tags: Pipe Flange