Flange Bolt Requirements
| Flange Size | Bolt Hole qty | Bolt Diameter | Bolt Length Min | Butterfly Length Min |
| 1/2" | 4 | 1/2 | 2 | |
| 3/4" | 4 | 1/2 | 2 | |
| 1" | 4 | 1/2 | 2-1/4 | |
| 1-1/4" | 4 | 1/2 | 2-1/4 | |
| 1-1/2" | 4 | 1/2 | 2-1/2 | |
| 2" | 4 | 5/8 | 3 | |
| 2-1/2" | 4 | 5/8 | 3-1/4 | 5 |
| 3" | 4 | 5/8 | 3-1/4 | 5 |
| 4" | 8 | 5/8 | 3-1/2 | 5-3/4 |
| 5" | 8 | 3/4 | 3-3/4 | 7 |
| 6" | 8 | 3/4 | 4 | 7 |
| 8" | 8 | 3/4 | 4-1/2 | 8 |
| 10" | 12 | 7/8 | 5 | 9-1/2 |
| 12" | 12 | 7/8 | 5 | 10 |
| 14" | 12 | 1 | 5 | |
| 16" | 12 | 1 | 5 | |
| 18" | 16 | 1-1/8 | 5 | |
| 20" | 20 | 1-1/8 | 6 | |
| 24" | 20 | 1-1/4 | 6 |