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 | 240 | 127.0 | 38.1 | 190.5 | 25.4 | 8 | 13.02 |
| 4 | 290 | 157.2 | 44.5 | 235.0 | 31.8 | 8 | 21.94 |
| 5 | 350 | 185.7 | 50.8 | 279.4 | 34.9 | 8 | 36.83 |
| 6 | 380 | 215.9 | 55.6 | 317.5 | 31.8 | 12 | 47.40 |
| 8 | 470 | 269.9 | 63.5 | 393.7 | 38.1 | 12 | 82.87 |
| 10 | 545 | 323.8 | 69.9 | 469.9 | 38.1 | 16 | 122.61 |
| 12 | 610 | 381.0 | 79.4 | 533.4 | 38.1 | 20 | 174.34 |
| 14 | 640 | 412.8 | 85.8 | 558.8 | 41.3 | 20 | 206.16 |
| 16 | 705 | 469.9 | 88.9 | 616.0 | 44.5 | 20 | 260.49 |
| 18 | 785 | 533.4 | 101.6 | 685.8 | 50.8 | 20 | 366.23 |
| 20 | 855 | 584.2 | 108.0 | 749.3 | 54.0 | 20 | 463.04 |
| 24 | 1040 | 692.2 | 139.7 | 901.7 | 66.7 | 20 | 876.34 |
