ANSI B16.5 Class 150 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 | 89 | 9.7 | 30 | 21.3 | 46 | 15.7 | 60.5 | 5/8 | 4 |
| ¾ | 99 | 11.2 | 38 | 26.7 | 51 | 20.8 | 69.8 | 5/8 | 4 |
| 1 | 108 | 12.7 | 49 | 33.5 | 54 | 26.7 | 79.2 | 5/8 | 4 |
| 1¼ | 117 | 14.2 | 59 | 42.2 | 56 | 35.1 | 88.9 | 5/8 | 4 |
| 1½ | 127 | 15.9 | 65 | 48.3 | 60 | 40.9 | 98.6 | 5/8 | 4 |
| 2 | 152 | 17.5 | 78 | 60.5 | 62 | 52.6 | 120.6 | 3/4 | 4 |
| 2½ | 178 | 20.6 | 90 | 73.2 | 68 | 62.7 | 139.7 | 3/4 | 4 |
| 3 | 190 | 22.4 | 108 | 88.9 | 68 | 78 | 152.4 | 3/4 | 4 |
| 3½ | 216 | 22.4 | 122 | 101.6 | 70 | 90.2 | 177.8 | 3/4 | 8 |
| 4 | 229 | 22.4 | 135 | 114.3 | 75 | 102.4 | 190.5 | 3/4 | 8 |
| 5 | 254 | 22.4 | 164 | 141.2 | 87 | 128.3 | 215.9 | 7/8 | 8 |
| 6 | 279 | 23.9 | 192 | 168.4 | 87 | 154.2 | 241.3 | 7/8 | 8 |
| 8 | 343 | 26.9 | 246 | 219.2 | 100 | 202.7 | 298.4 | 7/8 | 8 |
| 10 | 406 | 28.4 | 305 | 273 | 100 | 254.5 | 362 | 1 | 12 |
| 12 | 483 | 30.2 | 365 | 323.8 | 113 | 304.8 | 431.8 | 1 | 12 |
| 14 | 553 | 33.3 | 400 | 355.6 | 125 | 336.54 | 476.2 | 1⅛ | 12 |
| 16 | 597 | 35.1 | 457 | 406.4 | 125 | 387.34 | 539.8 | 1⅛ | 16 |
| 18 | 635 | 38.1 | 505 | 457.2 | 138 | 437.94 | 577.8 | 1¼ | 16 |
| 20 | 698 | 41.1 | 559 | 508 | 143 | 488.94 | 635 | 1¼ | 20 |
| 22 | 749 | 44.4 | 610 | 558.8 | 148 | 539.94 | 692.2 | 1⅜ | 20 |
| 24 | 813 | 46 | 663 | 609.6 | 151 | 590.94 | 749.3 | 1⅜ | 20 |