Pipe flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It also provides easy access for cleaning, inspection or modification.
| Nominal Pip Size | Outside Diameter of Flange | Diameter of Raised Face | Thickness of Flanges Min. | Diameter of Bolt Circle | Diameter of Bolt Holes | Number of Bolts | Approximate Weight kgs |
| NPS | O | R | tf | W | I | n | |
| 1/2 | 120 | 34.9 | 22.3 | 82.6 | 22.2 | 4 | 1.76 |
| 3/4 | 130 | 42.9 | 25.4 | 88.9 | 22.2 | 4 | 2.42 |
| 1 | 150 | 50.8 | 28.6 | 101.6 | 25.4 | 4 | 3.63 |
| 1 1/4 | 160 | 63.5 | 28.6 | 111.1 | 25.4 | 4 | 4.24 |
| 1 1/2 | 180 | 73.0 | 31.8 | 123.8 | 28.6 | 4 | 5.95 |
| 2 | 215 | 92.1 | 38.1 | 165.1 | 25.4 | 8 | 10.02 |
| 2 1/2 | 245 | 104.8 | 41.3 | 190.5 | 28.6 | 8 | 14.11 |
| 3 | 265 | 127.0 | 47.7 | 203.2 | 31.8 | 8 | 18.99 |
| 4 | 310 | 157.2 | 54.0 | 241.3 | 34.9 | 8 | 29.83 |
| 5 | 375 | 185.7 | 73.1 | 292.1 | 41.3 | 8 | 58.77 |
| 6 | 395 | 215.9 | 82.6 | 317.5 | 38.1 | 12 | 72.65 |
| 8 | 485 | 269.9 | 92.1 | 393.7 | 44.5 | 12 | 123.34 |
| 10 | 585 | 323.8 | 108.0 | 482.6 | 50.8 | 12 | 211.94 |
| 12 | 675 | 381.0 | 123.9 | 571.5 | 54.0 | 16 | 318.94 |
| 14 | 750 | 412.8 | 133.4 | 635.0 | 60.3 | 16 | 422.42 |
| 16 | 825 | 469.9 | 146.1 | 704.8 | 66.7 | 16 | 558.96 |
| 18 | 915 | 533.4 | 162.0 | 774.7 | 73.0 | 16 | 763.84 |
| 20 | 985 | 584.2 | 177.8 | 831.8 | 79.4 | 16 | 968.52 |
| 24 | 1170 | 692.2 | 203.2 | 990.6 | 92.1 | 16 | 1566.88 |
