ANSI B16.5 Forged Flanges
Class 400 Flange Dimensions
ASME B16.5
Class 400 is an intermediate class between 300 and 600, sharing bolt patterns with Class 600 but with reduced thickness. All dimensions are in inches.
| NPS | Flange OD | Thickness (min) | RF Diameter | Bolt Circle | # Bolts | Bolt Dia. | Hub Dia. | WN Length | Bore |
|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 3.75 | 0.56 | 1.38 | 2.62 | 4 | 1/2 | 1.19 | 2.06 | 0.88 |
| 3/4 | 4.62 | 0.62 | 1.69 | 3.25 | 4 | 5/8 | 1.50 | 2.25 | 1.09 |
| 1 | 4.88 | 0.69 | 2.00 | 3.50 | 4 | 5/8 | 1.94 | 2.44 | 1.36 |
| 1-1/4 | 5.25 | 0.75 | 2.50 | 3.88 | 4 | 5/8 | 2.31 | 2.56 | 1.70 |
| 1-1/2 | 6.12 | 0.81 | 2.88 | 4.50 | 4 | 3/4 | 2.56 | 2.69 | 1.97 |
| 2 | 6.50 | 0.88 | 3.62 | 5.00 | 8 | 5/8 | 3.06 | 2.75 | 2.44 |
| 2-1/2 | 7.50 | 1.00 | 4.12 | 5.88 | 8 | 3/4 | 3.56 | 3.00 | 2.94 |
| 3 | 8.25 | 1.12 | 5.00 | 6.62 | 8 | 3/4 | 4.25 | 3.12 | 3.57 |
| 3-1/2 | 9.00 | 1.19 | 5.50 | 7.25 | 8 | 3/4 | 4.69 | 3.19 | 4.07 |
| 4 | 10.75 | 1.38 | 6.19 | 9.25 | 8 | 7/8 | 5.31 | 3.50 | 4.57 |
| 5 | 13.00 | 1.56 | 7.31 | 11.00 | 8 | 1 | 6.44 | 4.00 | 5.66 |
| 6 | 14.00 | 1.62 | 8.50 | 11.75 | 12 | 1 | 7.56 | 4.25 | 6.72 |
| 8 | 16.50 | 1.88 | 10.62 | 13.75 | 12 | 1 | 9.69 | 4.75 | 8.72 |
| 10 | 20.00 | 2.19 | 12.75 | 17.00 | 16 | 1-1/8 | 11.75 | 5.38 | 10.88 |
| 12 | 22.00 | 2.31 | 15.00 | 19.25 | 20 | 1-1/8 | 13.75 | 5.75 | 12.88 |
| 14 | 23.75 | 2.44 | 16.25 | 20.75 | 20 | 1-1/4 | 15.00 | 6.19 | 14.14 |
| 16 | 27.00 | 2.62 | 18.50 | 24.00 | 20 | 1-3/8 | 17.00 | 6.38 | 16.16 |
| 18 | 29.25 | 2.81 | 21.00 | 25.75 | 20 | 1-1/2 | 19.00 | 7.00 | 18.18 |
| 20 | 32.00 | 3.00 | 23.00 | 28.50 | 24 | 1-1/2 | 21.00 | 7.25 | 20.20 |
| 24 | 37.00 | 3.50 | 27.25 | 33.00 | 24 | 1-5/8 | 25.00 | 8.25 | 24.25 |
