Dimension of Flange: The term “flange” typically refers to a projecting rim or edge on a pipe, valve, or other object that allows it to be connected to another object. Flanges are commonly used in piping systems to connect pipes, valves, and other equipment.
Flanges come in various sizes and dimensions, and their dimensions are specified according to industry standards. The dimensions of a flange include parameters such as:
-
Nominal Pipe Size (NPS):
This refers to the approximate interior diameter of the flange and the pipe it is designed to fit. It is often expressed in inches. -
Flange Outer Diameter (OD):
The overall diameter of the flange. -
Flange Inner Diameter (ID):
The diameter of the opening or bore of the flange. -
Flange Thickness (T):
The thickness of the flange material. -
Bolt Circle Diameter (BCD):
The diameter of the circle formed by the centers of the bolt holes in the flange. -
Number of Bolt Holes:
The quantity of bolt holes in the flange. -
Bolt Hole Diameter: The diameter of the bolt holes in the flange.
-
Raised Face (RF) or Flat Face (FF):
Flanges can have a raised surface (RF) or a flat surface (FF) where the gasket sits. -
Pressure Class or Rating:
Flanges are often designed to withstand specific pressure levels, and the pressure class or rating is an important dimension. -
Flange Face Finish:
The surface finish of the flange face, which affects how the gasket seals.
The dimensions of flanges can vary based on the type of flange, its purpose, and the industry standards it adheres to. Common flange standards include ANSI/ASME (American National Standards Institute/American Society of Mechanical Engineers), DIN (Deutsches Institut für Normung – German Institute for Standardization), and EN (European Norm) standards.
It’s important to refer to specific industry standards or manufacturer documentation to determine the exact dimensions of a flange for a particular application.
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DIMENSION OF RAISED FLANGES
| N. B. | Out Dia | Thickness | Bolt Circle Dia | No. of Bolt | Dia of Holes |
| 80 | 200 | 21 | 160 | 4 | 19 |
| 100 | 220 | 22 | 180 | 8 | 19 |
| 125 | 250 | 22.5 | 210 | 8 | 19 |
| 150 | 285 | 23 | 240 | 8 | 23 |
| 200 | 340 | 24.5 | 295 | 8 | 23 |
| 250 | 395 | 26 | 350 | 12 | 23 |
| 300 | 445 | 27.5 | 400 | 12 | 23 |
| 350 | 505 | 29 | 450 | 16 | 23 |
| 400 | 565 | 30 | 515 | 16 | 28 |
| 450 | 615 | 31.5 | 565 | 20 | 28 |
| 500 | 670 | 33 | 620 | 20 | 28 |
| 600 | 780 | 36 | 725 | 20 | 31 |
| 700 | 895 | 38.5 | 840 | 24 | 31 |
| 750 | 960 | 40 | 900 | 24 | 31 |
| 800 | 1015 | 41.5 | 950 | 24 | 34 |
DIMENSION OF FLANGES AS PER TABLE BS-10
| Nominal Pipe Size | OD of Pipe | O.D. | P.C.D. | No.of Bolt | Dia of Bolt | Thickness |
| 1/2″ | 21.3 | 95.3 | 66.7 | 4 | 12.7 | 4.8 |
| 3/4″ | 26.7 | 101.6 | 73 | 4 | 12.7 | 4.8 |
| 1″ | 33.4 | 114.3 | 82.6 | 4 | 12.7 | 4.8 |
| 1 1/4″ | 42.2 | 120.7 | 87.3 | 4 | 12.7 | 6.4 |
| 1 1/2″ | 48.3 | 133.4 | 98.4 | 4 | 12.7 | 6.4 |
| 2″ | 60.3 | 152.4 | 114.3 | 4 | 15.9 | 7.9 |
| 2 1/2″ | 73 | 165.1 | 127 | 4 | 15.9 | 7.9 |
| 3″ | 88.9 | 184.2 | 146.1 | 4 | 15.9 | 9.5 |
| 3 1/2″ | 101.6 | 203.2 | 165.1 | 4 | 15.9 | 9.5 |
| 4″ | 114.3 | 215.9 | 177.8 | 4 | 15.9 | 9.5 |
| 5″ | 141.3 | 254 | 209.6 | 8 | 15.9 | 12.7 |
| 6″ | 168.3 | 279.4 | 228.6 | 8 | 15.9 | 12.7 |
| 7″ | 190.5 | 304.8 | 260.4 | 8 | 15.9 | 12.7 |
| 8″ | 219.1 | 336.6 | 292.1 | 8 | 15.9 | 12.7 |
| 9″ | 244.5 | 368.3 | 323.9 | 8 | 15.9 | 15.9 |
| 10″ | 273 | 406.4 | 355.6 | 8 | 19.1 | 15.9 |
| 12″ | 323.9 | 457.2 | 406.4 | 12 | 19.1 | 15.9 |
| 14″ | 355.6 | 527.1 | 469.9 | 12 | 22.2 | 19.1 |
| 16″ | 406.4 | 577.9 | 520.7 | 12 | 22.2 | 19.1 |
| 18″ | 457.2 | 641.4 | 584.2 | 12 | 22.2 | 22.2 |
| 20″ | 508 | 704.9 | 641.4 | 16 | 22.5 | 25.4 |
| 24″ | 609.6 | 825.5 | 755.7 | 16 | 25.4 | 28.6 |
Working Steam Pressure upto 100 Ibs per sq. Inch
| Nominal Pipe Size | O.D. of Pipe | O.D. | P.C.D. | No. of Bolt | Dia of Bolt | Thickess |
| 1/2″ | 21.3 | 95.3 | 66.3 | 4 | 12.7 | 6.4 |
| 3/4″ | 26.7 | 101.6 | 73 | 4 | 12.7 | 6.4 |
| 1″ | 33.4 | 114.3 | 82.6 | 4 | 12.7 | 7.1 |
| 1.1/4″ | 42.2 | 120.7 | 87.3 | 4 | 12.7 | 7.9 |
| 1.1/2″ | 48.3 | 133.4 | 98.4 | 4 | 12.7 | 8.7 |
| 2″ | 60.3 | 152.4 | 114.3 | 4 | 15.9 | 9.5 |
| 2.1/2″ | 73 | 165.1 | 127 | 4 | 15.9 | 10.3 |
| 3″ | 88.9 | 184.2 | 146.1 | 4 | 15.9 | 11.1 |
| 3.1/2″ | 101.6 | 203.2 | 165.1 | 8 | 15.9 | 11.9 |
| 4″ | 114.3 | 215.9 | 177.8 | 8 | 15.9 | 12.7 |
| 5″ | 141.3 | 254 | 209.6 | 8 | 15.9 | 14.3 |
| 6″ | 168.3 | 279.4 | 228.6 | 8 | 19.1 | 17.5 |
| 7″ | 190.5 | 304.8 | 260.4 | 8 | 19.1 | 19.1 |
| 8″ | 219.1 | 336.6 | 292.1 | 8 | 19.1 | 19.1 |
| 9″ | 244.5 | 368.3 | 323.9 | 12 | 19.1 | 20.6 |
| 10″ | 273 | 406.4 | 355.6 | 12 | 19.1 | 22.2 |
| 12″ | 323.9 | 257.2 | 406.4 | 12 | 22.2 | 25.4 |
| 14″ | 355.6 | 527.2 | 469.9 | 12 | 22.2 | 25.4 |
| 16″ | 406.4 | 577.9 | 520.7 | 12 | 22.2 | 25.4 |
| 18″ | 457.2 | 641.4 | 584.2 | 16 | 22.2 | 28.6 |
| 20″ | 508 | 704.9 | 647.4 | 16 | 22.2 | 31.8 |
| 24″ | 609.6 | 825.5 | 755.7 | 16 | 25.4 | 38.1 |
Working Steam Pressure above 100 Ibs and upto150 Ibs per sq. Inch
| Nominal Pipe Size | O.D. of Pipe | O.D. | P.C.D. | No. of Bolt | Dia of Bolt | Thickness |
| 1/2″ | 21.3 | 95.3 | 66.7 | 4 | 12.7 | 9.5 |
| 3/4″ | 26.7 | 101.6 | 73 | 4 | 12.7 | 9.5 |
| 1″ | 33.4 | 120.7 | 87.3 | 4 | 15.9 | 9.5 |
| 1.1/4″ | 42.2 | 133.4 | 98.4 | 4 | 15.9 | 12.7 |
| 1.1/2″ | 48.3 | 1397 | 104.8 | 4 | 15.9 | 12.7 |
| 2″ | 60.3 | 165.1 | 127 | 4 | 15.9 | 15.9 |
| 2.1/2″ | 73 | 184.2 | 146.1 | 8 | 15.9 | 15.9 |
| 3″ | 88.9 | 203.2 | 165.1 | 8 | 15.9 | 15.9 |
| 3.1/2″ | 101.6 | 215.9 | 177.8 | 8 | 15.9 | 19.1 |
| 4″ | 114.3 | 228.6 | 190.5 | 8 | 15.9 | 19.1 |
| 5″ | 141.3 | 279.4 | 235 | 8 | 19.1 | 22.2 |
| 6″ | 168.3 | 304.8 | 260.4 | 12 | 19.1 | 22.2 |
| 7″ | 190.5 | 336.6 | 292.1 | 12 | 19.1 | 22.2 |
| 8″ | 219.1 | 368.3 | 323.9 | 12 | 19.1 | 25.4 |
| 9″ | 244.5 | 406.4 | 355.6 | 12 | 22.2 | 25.4 |
| 10″ | 273 | 431.8 | 381 | 12 | 22.2 | 25.4 |
| 12″ | 323.9 | 489 | 438.2 | 16 | 22.2 | 28.6 |
| 14′ | 355.6 | 552.5 | 495.3 | 16 | 25.4 | 31.8 |
| 16″ | 406.4 | 609.6 | 552.5 | 20 | 25.4 | 31.8 |
| 18″ | 457.2 | 673.8 | 609.6 | 20 | 28.6 | 34.9 |
| 20″ | 508 | 736.9 | 673.1 | 24 | 28.6 | 38.1 |
| 24″ | 609.6 | 850.9 | 781.1 | 24 | 31.8 | 41.3 |
Working Steam Pressure above 150 Ibs and upto 250 Ibs per sq. Inch
| Nominal Pipe Size | O.D. of Pipe | O.D. | P.C.D. | No. of Bolt | Dia of Bolt | Thickness |
| 1/2″ | 21.3 | 114.3 | 82.6 | 4 | 15.9 | 12.7 |
| 3/4″ | 26.7 | 114.3 | 82.6 | 4 | 15.9 | 12.7 |
| 1″ | 33.4 | 120.7 | 87.3 | 4 | 15.9 | 14.3 |
| 1.1/4″ | 42.2 | 133.4 | 98.4 | 4 | 15.9 | 17.5 |
| 1.1/2″ | 48.3 | 139.7 | 104.8 | 4 | 15.9 | 17.5 |
| 2″ | 60.3 | 165.1 | 127 | 4 | 15.9 | 19.1 |
| 2.1/2″ | 73 | 184.2 | 146.1 | 8 | 15.9 | 19.1 |
| 3″ | 88.9 | 203.2 | 165.1 | 8 | 15.9 | 22.2 |
| 3.1/2″ | 101.6 | 215.9 | 177.8 | 8 | 15.9 | 22.2 |
| 4″ | 114.3 | 228.6 | 190.5 | 8 | 15.9 | 25.4 |
| 5″ | 141.3 | 279.4 | 235 | 8 | 19.1 | 28.6 |
| 6″ | 168.3 | 304.8 | 260.4 | 12 | 19.1 | 28.6 |
| 7″ | 190.5 | 336.6 | 292.1 | 12 | 19.1 | 31.8 |
| 8″ | 219.1 | 368.3 | 323.9 | 12 | 19.1 | 31.8 |
| 9″ | 244.5 | 406.4 | 355.6 | 12 | 22.2 | 34.9 |
| 10″ | 273 | 431.8 | 381 | 12 | 22.2 | 34.9 |
| 12″ | 323.9 | 489 | 438.2 | 16 | 22.2 | 38.1 |
| 14′ | 355.6 | 552.5 | 495.3 | 16 | 25.4 | 41.3 |
| 16″ | 406.4 | 609.6 | 552.5 | 20 | 25.4 | 44.5 |
| 18″ | 457.2 | 673.8 | 609.6 | 20 | 28.6 | 47.6 |
| 20″ | 508 | 736.9 | 673.1 | 24 | 28.6 | 50.8 |
| 24″ | 609.6 | 850.9 | 781.1 | 24 | 31.8 | 57.2 |
