In some industries, particularly the pressure vessels, heat exchangers, refinery, petrochemical, and offshore industries, the term "Standard Connection Flange" may be used informally or by individual manufacturers to describe a family of heavy-duty nozzle connection flanges. The hub of the flange is straight and thicker than the taper of the weld neck flange (WNF). This flange has a raised face.
Long Weld Neck Flange (LWN) - A flange with an extended tapered neck that is butt-welded directly to a vessel or piping component. The long hub provides a gradual transition of stresses from the flange into the attached component, making it suitable for high-pressure, high-temperature, cyclic, or severe-service applications.
Heavy Barrel Flange - A variation of the long weld neck design having a thicker, more robust barrel (hub). The increased wall thickness provides additional reinforcement for heavy loads, high external piping forces, thermal stresses, and demanding operating conditions. Heavy barrel flanges are commonly used on pressure vessel nozzles and critical process equipment.
Full Barrel Flange - A flange in which the barrel extends the full length between the flange face and the weld end, maintaining a relatively constant wall thickness rather than a tapered neck. This design is often selected when additional reinforcement is required or when specified by equipment manufacturers for vessel nozzle connections.
Standard Connection Flange Datasheets | |||
|---|---|---|---|
| Class | Long Weld Neck Flange Raised Face | Heavy Barrel Flange Raised Face | Full Barrel Flange Raised Face |
| ANSI 150 | LWN, ANSI Class 150, B16.5 (in) | HBF, ANSI Class 150, B16.5 (in) | FBF, ANSI Class 150, B16.5 (in) |
| ANSI 300 | LWN, ANSI Class 300, B16.5 (in) | ||
| ANSI 400 | LWN, ANSI Class 400, B16.5 (in) | ||
| ANSI 600 | LWN, ANSI Class 600, B16.5 (in) | ||
| ANSI 900 | LWN, ANSI Class 900, B16.5 (in) | ||
| ANSI 1500 | LWN, ANSI Class 1500, B16.5 (in) | ||
| ANSI 2500 | LWN, ANSI Class 2500, B16.5 (in) | ||
Standard Connection Flange Standards
- ASME Standards
- ASME B16.5 - Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
