Cast Iron Flanges - ASME/ANSI Class 125
ASME/ANSI B16.1 Cast Iron Pipe Flanges and Flanged Fittings - Class 125 Flanges - outside and inside diameters, bolt circles, numbers and diameters of bolts.
ASME/ANSI B16.1 - 1998 - Cast Iron Pipe Flanges and Flanged Fittings - Class 125 Flanges - outside and inside diameters, bolt circles, numbers and diameters of bolts:
| Pipe Size (inches) | Outside Diameter (inches) | Number of Bolt Holes | Bolt Hole Diameter (inches) | Bolt Circle (inches) |
|---|---|---|---|---|
| 1 | 4-1/4 | 4 | 5/8 | 3-1/8 |
| 1-1/4 | 4-5/8 | 4 | 5/8 | 3-1/2 |
| 1-1/2 | 5 | 4 | 5/8 | 3-7/8 |
| 2 | 6 | 4 | 3/4 | 4-3/4 |
| 2-1/2 | 7 | 4 | 3/4 | 5-1/2 |
| 3 | 7-1/2 | 4 | 3/4 | 6 |
| 3-1/2 | 8-1/2 | 8 | 3/4 | 7 |
| 4 | 9 | 8 | 3/4 | 7-1/2 |
| 5 | 10 | 8 | 7/8 | 8-1/2 |
| 6 | 11 | 8 | 7/8 | 9-1/2 |
| 8 | 13-1/2 | 8 | 7/8 | 11-3/4 |
| 10 | 16 | 12 | 1 | 14-1/4 |
| 12 | 19 | 12 | 1 | 17 |
| 14 | 21 | 12 | 1-1/8 | 18-3/4 |
| 16 | 23-1/2 | 16 | 1-1/8 | 21-1/4 |
| 18 | 25 | 16 | 1-1/4 | 22-3/4 |
| 20 | 27-1/2 | 20 | 1-1/4 | 25 |
| 24 | 32 | 20 | 1-3/8 | 29-1/2 |
| 30 | 38-3/4 | 28 | 1-3/8 | 36 |
| 36 | 46 | 32 | 1-5/8 | 42-3/4 |
| 42 | 53 | 36 | 1-5/8 | 49-1/2 |
| 48 | 59-1/2 | 44 | 1-5/8 | 56 |
| 54 | 66-1/4 | 44 | 2 | 62-3/4 |
| 60 | 73 | 52 | 2 | 69-1/4 |
- 1 inch = 25.4 mm
