ANSI B16.5 Class 600 Welding Neck Flanges
| NPS | Outside Diameter (O) | Thickness (T) | Hub Diameter (X) | Neck Diameter (A) | Length Through Hub (Y) | Bore (B) | Diameter of Bolt Circle (C) | Diameter of Bolt Holes (in) | Number of Bolts |
|---|---|---|---|---|---|---|---|---|---|
| ½ | 95 | 14.2 | 38 | 21.3 | 52 | 15.7 | 66.5 | 5/8 | 4 |
| ¾ | 117 | 15.7 | 48 | 26.7 | 57 | 20.8 | 82.6 | 3/4 | 4 |
| 1 | 124 | 17.5 | 54 | 33.5 | 62 | 26.7 | 88.9 | 3/4 | 4 |
| 1¼ | 133 | 20.6 | 64 | 42.2 | 67 | 35.1 | 98.6 | 3/4 | 4 |
| 1½ | 155 | 22.4 | 70 | 48.3 | 70 | 40.9 | 114.3 | 7/8 | 4 |
| 2 | 165 | 25.4 | 84 | 60.5 | 73 | 52.6 | 127 | 3/4 | 8 |
| 2½ | 190 | 28.4 | 100 | 73.2 | 79 | 62.7 | 149.4 | 7/8 | 8 |
| 3 | 210 | 31.8 | 117 | 88.9 | 83 | 78 | 168.1 | 7/8 | 8 |
| 3½ | 229 | 35.1 | 133 | 101.6 | 86 | 90.2 | 184.2 | 1 | 8 |
| 4 | 273 | 38.1 | 152 | 114.3 | 102 | 102.4 | 215.9 | 1 | 8 |
| 5 | 330 | 44.4 | 189 | 141.2 | 114 | 128.3 | 266.7 | 1⅛ | 8 |
| 6 | 356 | 47.8 | 222 | 168.4 | 117 | 154.2 | 292.1 | 1⅛ | 12 |
| 8 | 419 | 55.6 | 273 | 219.2 | 133 | 202.7 | 349.2 | 1¼ | 12 |
| 10 | 508 | 63.5 | 343 | 273 | 152 | 254.5 | 431.8 | 1⅜ | 16 |
| 12 | 559 | 66.5 | 400 | 323.8 | 155 | 304.8 | 489 | 1⅜ | 20 |
| 14 | 603 | 69.8 | 432 | 355.6 | 165 | 336.54 | 527 | 1½ | 20 |
| 16 | 686 | 76.2 | 495 | 406.4 | 178 | 387.34 | 603.2 | 1⅝ | 20 |
| 18 | 743 | 82.6 | 546 | 457.2 | 184 | 437.94 | 654 | 1¾ | 20 |
| 20 | 813 | 88.9 | 610 | 508 | 190 | 488.94 | 723.9 | 1¾ | 24 |
| 22 | 870 | 95.2 | 663 | 558.8 | 197 | 539.94 | 777.7 | 1⅞ | 24 |
| 24 | 940 | 101.6 | 718 | 609.6 | 203 | 590.94 | 838.2 | 2 | 24 |