ANSI B16.5 Class 2500 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 | 5.25 mm | 1.19 mm | 1.38 mm | 7 lb | 3.50 mm | 4 | 0.88 mm |
| 3/4 | 5.50 mm | 1.25 mm | 1.69 mm | 8 lb | 3.75 mm | 4 | 0.88 mm |
| 1 | 6.25 mm | 1.38 mm | 2.00 mm | 11 lb | 4.25 mm | 4 | 1.00 mm |
| 1 1/4 | 7.25 mm | 1.50 mm | 2.50 mm | 17 lb | 5.13 mm | 4 | 1.13 mm |
| 1 1/2 | 8.00 mm | 1.75 mm | 2.88 mm | 23 lb | 5.75 mm | 4 | 1.25 mm |
| 2 | 9.25 mm | 2.00 mm | 3.63 mm | 39 lb | 6.75 mm | 8 | 1.13 mm |
| 2 1/2 | 10.50 mm | 2.25 mm | 4.13 mm | 56 lb | 7.75 mm | 8 | 1.25 mm |
| 3 | 12.00 mm | 2.63 mm | 5.00 mm | 86 lb | 9.00 mm | 8 | 1.38 mm |
| 4 | 14.00 mm | 3.00 mm | 6.19 mm | 135 lb | 10.75 mm | 8 | 1.63 mm |
| 5 | 16.50 mm | 3.63 mm | 7.31 mm | 225 lb | 12.75 mm | 8 | 1.88 mm |
| 6 | 19.00 mm | 4.25 mm | 8.50 mm | 345 lb | 14.50 mm | 8 | 2.13 mm |
| 8 | 21.75 mm | 5.00 mm | 10.63 mm | 530 lb | 17.25 mm | 12 | 2.13 mm |
| 10 | 26.50 mm | 6.50 mm | 12.75 mm | 1025 lb | 21.25 mm | 12 | 2.63 mm |
| 12 | 30.00 mm | 7.25 mm | 15.00 mm | 1300 lb | 24.38 mm | 12 | 2.88 mm |