Industry Standard Class 350 Welding Neck Flanges
| Nominal Pipe Size | Outside Diameter (O) | Thickness (T) | Raised Face Diameter (R) | Length Thru Hub (Y) | Base of Hub Diameter (X) | Diameter of Hub at Bevel (A) | Approximate Weight | Bolt Circle (C) | Number of Holes | Diameter of Bolt Holes |
|---|---|---|---|---|---|---|---|---|---|---|
| 26 | 32.75 mm | 2.50 mm | 29.50 mm | 5.00 mm | 27.88 mm | Specified by purchaser | 245 lb | 30.63 mm | 28 | 1.13 mm |
| 28 | 34.75 mm | 2.50 mm | 31.50 mm | 5.00 mm | 29.88 mm | Specified by purchaser | 260 lb | 32.63 mm | 28 | 1.13 mm |
| 30 | 37.00 mm | 2.63 mm | 33.75 mm | 5.25 mm | 32.13 mm | Specified by purchaser | 305 lb | 34.88 mm | 32 | 1.13 mm |
| 32 | 39.00 mm | 2.75 mm | 35.75 mm | 5.50 mm | 34.13 mm | Specified by purchaser | 340 lb | 36.88 mm | 36 | 1.13 mm |
| 34 | 41.00 mm | 2.88 mm | 37.75 mm | 5.75 mm | 36.13 mm | Specified by purchaser | 375 lb | 38.88 mm | 40 | 1.13 mm |
| 36 | 43.75 mm | 3.13 mm | 40.25 mm | 6.13 mm | 38.50 mm | Specified by purchaser | 480 lb | 41.50 mm | 40 | 1.25 mm |
| 38 | 45.75 mm | 3.13 mm | 42.25 mm | 6.13 mm | 40.50 mm | Specified by purchaser | 510 lb | 43.50 mm | 40 | 1.25 mm |
| 40 | 47.75 mm | 3.25 mm | 44.25 mm | 6.25 mm | 42.50 mm | Specified by purchaser | 540 lb | 45.50 mm | 44 | 1.25 mm |
| 42 | 50.00 mm | 3.50 mm | 46.50 mm | 6.50 mm | 44.75 mm | Specified by purchaser | 640 lb | 47.75 mm | 48 | 1.25 mm |
| 44 | 52.75 mm | 3.75 mm | 48.88 mm | 6.75 mm | 46.75 mm | Specified by purchaser | 760 lb | 50.25 mm | 44 | 1.38 mm |
| 46 | 54.75 mm | 4.25 mm | 50.88 mm | 7.25 mm | 48.75 mm | Specified by purchaser | 880 lb | 52.25 mm | 48 | 1.38 mm |
| 48 | 56.75 mm | 4.25 mm | 52.88 mm | 7.25 mm | 50.75 mm | Specified by purchaser | 920 lb | 54.25 mm | 48 | 1.38 mm |
| 52 | 61.50 mm | 4.25 mm | 57.25 mm | 7.50 mm | 55.00 mm | Specified by purchaser | 1075 lb | 58.75 mm | 52 | 1.50 mm |
| 54 | 63.50 mm | 4.50 mm | 59.25 mm | 7.75 mm | 57.00 mm | Specified by purchaser | 1200 lb | 60.75 mm | 52 | 1.50 mm |
| 60 | 69.50 mm | 4.50 mm | 65.25 mm | 8.00 mm | 63.00 mm | Specified by purchaser | 1325 lb | 66.75 mm | 60 | 1.50 mm |
| 66 | 77.00 mm | 4.00 mm | 72.38 mm | 8.50 mm | 70.00 mm | Specified by purchaser | 1675 lb | 74.00 mm | 60 | 1.63 mm |
| 72 | 83.00 mm | 4.00 mm | 78.38 mm | 9.00 mm | 76.00 mm | Specified by purchaser | 1850 lb | 80.00 mm | 72 | 1.63 mm |
| 84 | 96.50 mm | 5.00 mm | 91.25 mm | 10.00 mm | 89.00 mm | Specified by purchaser | 2950 lb | 93.25 mm | 80 | 1.75 mm |
| 96 | 109.25 mm | 6.25 mm | 103.88 mm | 11.25 mm | 101.25 mm | Specified by purchaser | 4250 lb | 105.75 mm | 84 | 1.88 mm |