AWWA C207 — Flange drilling — Class D
AWWA C207 Flange drilling — Class D — 10 sizes.
| NPS | Flange OD (in) | Bolt circle (in) | No. of bolts | Bolt hole dia (in) | Thickness (in) |
|---|---|---|---|---|---|
| 4 | 9 | 7.5 | 8 | 0.75 | 0.625 |
| 6 | 11 | 9.5 | 8 | 0.875 | 0.688 |
| 8 | 13.5 | 11.75 | 8 | 0.875 | 0.688 |
| 10 | 16 | 14.25 | 12 | 1 | 0.688 |
| 12 | 19 | 17 | 12 | 1 | 0.812 |
| 14 | 21 | 18.75 | 12 | 1.125 | 0.938 |
| 16 | 23.5 | 21.25 | 16 | 1.125 | 1 |
| 18 | 25 | 22.75 | 16 | 1.25 | 1.063 |
| 20 | 27.5 | 25 | 20 | 1.25 | 1.125 |
| 24 | 32 | 29.5 | 20 | 1.375 | 1.25 |
- Class D: 175 psi for 4-12", 150 psi for 14" and larger.