Flange Hole Size Reference Chart
NOTE: Refer to the chart showing the pressure of your pipe; then find your pipe size. Chart will show you the number of holes in your standard flange and the diameter of the holes
Forged Steel Flanges – 150 lb
| PIPE SIZE (inch) | No. of Holes | Diameter of Hole (inch) |
|---|---|---|
| 1/2 | 4 | 5/8 |
| 3/4 | 4 | 5/8 |
| 1 | 4 | 5/8 |
| 1-1/4 | 4 | 5/8 |
| 1-1/2 | 4 | 5/8 |
| 2 | 4 | 3/4 |
| 2-1/2 | 4 | 3/4 |
| 3 | 4 | 3/4 |
| 3-1/2 | 8 | 3/4 |
| 4 | 8 | 3/4 |
| 5 | 8 | 7/8 |
| 6 | 8 | 7/8 |
| 8 | 8 | 7/8 |
| 10 | 12 | 1 |
| 12 | 12 | 1 |
| 14 | 12 | 1-1/8 |
| 16 | 16 | 1-1/8 |
| 18 | 16 | 1-1/8 |
Forged Steel Flanges – 300 lb
| PIPE SIZE (inch) | No. of Holes | Diameter of Hole (inch) |
|---|---|---|
| 1/2 | 4 | 5/8 |
| 3/4 | 4 | 3/4 |
| 1 | 4 | 3/4 |
| 1-1/4 | 4 | 3/4 |
| 1-1/2 | 4 | 7/8 |
| 2 | 8 | 7/8 |
| 2-1/2 | 8 | 7/8 |
| 3 | 8 | 7/8 |
| 3-1/2 | 8 | 7/8 |
| 4 | 8 | 7/8 |
| 5 | 8 | 7/8 |
| 6 | 12 | 7/8 |
| 8 | 12 | 1 |
| 10 | 16 | 1-1/8 |
| 12 | 16 | 1-1/8 |
| 14 | 20 | 1-1/8 |
| 16 | 20 | 1-3/8 |
| 18 | 24 | 1-3/8 |
Forged Steel Flanges – 400 lb
| PIPE SIZE (inch) | No. of Holes | Diameter of Hole (inch) |
|---|---|---|
| 1/2 | 4 | 5/8 |
| 3/4 | 4 | 3/4 |
| 1 | 4 | 3/4 |
| 1-1/4 | 4 | 3/4 |
| 1-1/2 | 4 | 7/8 |
| 2 | 8 | 7/8 |
| 2-1/2 | 8 | 7/8 |
| 3 | 8 | 7/8 |
| 3-1/2 | 8 | 1 |
| 4 | 8 | 1 |
| 5 | 8 | 1 |
| 6 | 12 | 1 |
| 8 | 12 | 1-1/8 |
| 10 | 16 | 1-1/8 |
| 12 | 16 | 1-3/8 |
| 14 | 20 | 1-3/8 |
| 16 | 20 | 1-1/2 |
| 18 | 24 | 1-1/2 |
Forged Steel Flanges – 600 lb
| PIPE SIZE (inch) | No. of Holes | Diameter of Hole (inch) |
|---|---|---|
| 1/2 | 4 | 5/8 |
| 3/4 | 4 | 3/4 |
| 1 | 4 | 3/4 |
| 1-1/4 | 4 | 3/4 |
| 1-1/2 | 4 | 7/8 |
| 2 | 8 | 7/8 |
| 2-1/2 | 8 | 7/8 |
| 3 | 8 | 7/8 |
| 3-1/2 | 8 | 1 |
| 4 | 8 | 1 |
| 5 | 8 | 1-1/8 |
| 6 | 12 | 1-1/8 |
| 8 | 12 | 1-1/4 |
| 10 | 16 | 1-3/8 |
| 12 | 20 | 1-3/8 |
| 14 | 20 | 1-1/2 |
| 16 | 20 | 1-5/8 |
| 18 | 20 | 1-3/4 |
Forged Steel Flanges – 900 lb
| PIPE SIZE (inch) | No. of Holes | Diameter of Hole (inch) |
|---|---|---|
| 1/2 | 4 | 7/8 |
| 3/4 | 4 | 7/8 |
| 1 | 4 | 1 |
| 1-1/4 | 4 | 1 |
| 1-1/2 | 4 | 1 |
| 2 | 8 | 1 |
| 2-1/2 | 8 | 1-1/8 |
| 3 | 8 | 1-1/8 |
| 4 | 8 | 1-1/4 |
| 5 | 8 | 1-1/4 |
| 6 | 12 | 1-1/4 |
| 8 | 12 | 1-1/2 |
| 10 | 16 | 1-1/2 |
| 12 | 20 | 1-1/2 |
| 14 | 20 | 1-5/8 |
| 16 | 20 | 1-3/4 |
| 18 | 20 | 2 |
Forged Steel Flanges – 1500 lb
| PIPE SIZE (inch) | No. of Holes | Diameter of Hole (inch) |
|---|---|---|
| 1/2 | 4 | 7/8 |
| 3/4 | 4 | 7/8 |
| 1 | 4 | 1 |
| 1-1/4 | 4 | 1 |
| 1-1/2 | 4 | 1 |
| 2 | 8 | 1 |
| 2-1/2 | 8 | 1-1/8 |
| 3 | 8 | 1-1/4 |
| 4 | 8 | 1-3/8 |
| 5 | 8 | 1-5/8 |
| 6 | 12 | 1-1/2 |
| 8 | 12 | 1-3/4 |
| 10 | 12 | 2 |
| 12 | 16 | 2-1/8 |
| 14 | 16 | 2-3/8 |
| 16 | 16 | 2-3/8 |
| 18 | 16 | 2-7/8 |