ANSI B16.5 Class 300 Blind Flanges
| Nominal Pipe Size | Outside Diameter (O) | Thickness (T) | Raised Face Diameter (R) | Approximate Weight | Bolt Circle (C) | Number of Holes | Diameter of Holes |
|---|---|---|---|---|---|---|---|
| 1/2 | 3.75 mm | 0.56 mm | 1.38 mm | 2 lb | 2.63 mm | 4 | 0.63 mm |
| 3/4 | 4.63 mm | 0.63 mm | 1.69 mm | 3 lb | 3.25 mm | 4 | 0.75 mm |
| 1 | 4.88 mm | 0.69 mm | 2.00 mm | 3 lb | 3.50 mm | 4 | 0.75 mm |
| 1 1/4 | 5.25 mm | 0.75 mm | 2.50 mm | 4 lb | 3.88 mm | 4 | 0.75 mm |
| 1 1/2 | 6.13 mm | 0.81 mm | 2.88 mm | 6 lb | 4.50 mm | 4 | 0.88 mm |
| 2 | 6.50 mm | 0.88 mm | 3.63 mm | 8 lb | 5.00 mm | 8 | 0.75 mm |
| 2 1/2 | 7.50 mm | 1.00 mm | 4.13 mm | 12 lb | 5.88 mm | 8 | 0.88 mm |
| 3 | 8.25 mm | 1.13 mm | 5.00 mm | 16 lb | 6.63 mm | 8 | 0.88 mm |
| 3 1/2 | 9.00 mm | 1.19 mm | 5.50 mm | 21 lb | 7.25 mm | 8 | 0.88 mm |
| 4 | 10.00 mm | 1.25 mm | 6.19 mm | 27 lb | 7.88 mm | 8 | 0.88 mm |
| 5 | 11.00 mm | 1.38 mm | 7.31 mm | 35 lb | 9.25 mm | 8 | 0.88 mm |
| 6 | 12.50 mm | 1.44 mm | 8.50 mm | 50 lb | 10.63 mm | 12 | 0.88 mm |
| 8 | 15.00 mm | 1.63 mm | 10.63 mm | 81 lb | 13.00 mm | 12 | 1.00 mm |
| 10 | 17.50 mm | 1.88 mm | 12.75 mm | 124 lb | 15.25 mm | 16 | 1.13 mm |
| 12 | 20.50 mm | 2.00 mm | 15.00 mm | 185 lb | 17.75 mm | 16 | 1.25 mm |
| 14 | 23.00 mm | 2.13 mm | 16.25 mm | 250 lb | 20.25 mm | 20 | 1.25 mm |
| 16 | 25.50 mm | 2.25 mm | 18.50 mm | 295 lb | 22.50 mm | 20 | 1.38 mm |
| 18 | 28.00 mm | 2.38 mm | 21.00 mm | 395 lb | 24.75 mm | 24 | 1.38 mm |
| 20 | 30.50 mm | 2.50 mm | 23.00 mm | 505 lb | 27.00 mm | 24 | 1.38 mm |
| 22 | 33.00 mm | 2.63 mm | 25.25 mm | 640 lb | 29.25 mm | 24 | 1.63 mm |
| 24 | 36.00 mm | 2.75 mm | 27.25 mm | 790 lb | 32.00 mm | 24 | 1.63 mm |