The table below provides the gasket dimensions for American Water Works Association flanges of type C207 (steel flanges) and C228 (stainless steel flanges).
| NPS | ID | OD | Hole Qty | Hole Size | BCD |
|---|---|---|---|---|---|
| 4 | 4.5 | 10 | 8 | 0.88 | 7.88 |
| 5 | 5.56 | 11 | 8 | 0.88 | 9.25 |
| 6 | 6.63 | 12.5 | 12 | 0.88 | 10.62 |
| 8 | 8.63 | 15 | 12 | 1 | 13 |
| 10 | 10.75 | 17.5 | 16 | 1.12 | 15.25 |
| 12 | 12.75 | 20.5 | 16 | 1.25 | 17.75 |
| 14 | 14 | 23 | 20 | 1.25 | 20.25 |
| 16 | 16 | 25.5 | 20 | 1.38 | 22.5 |
| 18 | 18 | 28 | 24 | 1.38 | 24.75 |
| 20 | 20 | 30.5 | 24 | 1.38 | 27 |
| 24 | 24 | 36 | 24 | 1.63 | 32 |
| NPS | ID | OD | Hole Qty | Hole Size | BCD |
|---|---|---|---|---|---|
| 26 | 26 | 38.25 | 28 | 1.88 | 34.5 |
| 28 | 28 | 40.75 | 28 | 1.88 | 37 |
| 30 | 30 | 43 | 28 | 1.88 | 39.25 |
| 32 | 32 | 45.25 | 28 | 1.88 | 41.5 |
| 34 | 34 | 47.5 | 28 | 1.88 | 43.5 |
| 36 | 36 | 50 | 32 | 2.13 | 46 |
| 38 | 38 | 52.25 | 32 | 2.13 | 48 |
| 40 | 40 | 54.25 | 36 | 2.13 | 50.25 |
| 42 | 42 | 57 | 36 | 2.13 | 52.75 |
| 44 | 44 | 59.25 | 36 | 2.13 | 55 |
| 46 | 46 | 61.5 | 40 | 2.13 | 57.25 |
| 48 | 48 | 65 | 40 | 2.13 | 60.75 |
NPS = Nominal Pipe Size
ID = Inner Diameter
OD = Outer Diameter
BCD = Bolt Circle Diameter
General Note:
All dimensions are in inches.
Larger sizes as well as customized sizes can be furnished.
Bolt diameter should be 1/8″ less than the bolt hole size.
Standards:
ASME B16.5 – Pipe flanges and flanged fittings: NPS 4 through 24
ANSI B16.b – Taylor-Forge Class 250: NPS 26 through NPS 48 standard
No liability or guarantee for the correctness and completeness of the information provided
| NPS | ID | OD | Hole Qty | Hole Size | BCD |
|---|---|---|---|---|---|
| 4 | 4.5 | 10 | 8 | 0.88 | 7.88 |
| 5 | 5.56 | 11 | 8 | 0.88 | 9.25 |
| 6 | 6.63 | 12.5 | 12 | 0.88 | 10.62 |
| 8 | 8.63 | 15 | 12 | 1 | 13 |
| 10 | 10.75 | 17.5 | 16 | 1.12 | 15.25 |
| 12 | 12.75 | 20.5 | 16 | 1.25 | 17.75 |
| 14 | 14 | 23 | 20 | 1.25 | 20.25 |
| 16 | 16 | 25.5 | 20 | 1.38 | 22.5 |
| 18 | 18 | 28 | 24 | 1.38 | 24.75 |
| 20 | 20 | 30.5 | 24 | 1.38 | 27 |
| 24 | 24 | 36 | 24 | 1.63 | 32 |
| NPS | ID | OD | Hole Qty | Hole Size | BCD |
|---|---|---|---|---|---|
| 26 | 26 | 38.25 | 28 | 1.88 | 34.5 |
| 28 | 28 | 40.75 | 28 | 1.88 | 37 |
| 30 | 30 | 43 | 28 | 1.88 | 39.25 |
| 32 | 32 | 45.25 | 28 | 1.88 | 41.5 |
| 34 | 34 | 47.5 | 28 | 1.88 | 43.5 |
| 36 | 36 | 50 | 32 | 2.13 | 46 |
| 38 | 38 | 52.25 | 32 | 2.13 | 48 |
| 40 | 40 | 54.25 | 36 | 2.13 | 50.25 |
| 42 | 42 | 57 | 36 | 2.13 | 52.75 |
| 44 | 44 | 59.25 | 36 | 2.13 | 55 |
| 46 | 46 | 61.5 | 40 | 2.13 | 57.25 |
| 48 | 48 | 65 | 40 | 2.13 | 60.75 |
NPS = Nominal Pipe Size
ID = Inner Diameter
OD = Outer Diameter
BCD = Bolt Circle Diameter
General Note:
All dimensions are in inches.
Larger sizes as well as customized sizes can be furnished.
Bolt diameter should be 1/8″ less than the bolt hole size.
Standards:
ASME B16.5 – Pipe flanges and flanged fittings: NPS 4 through 24
ANSI B16.b – Taylor-Forge Class 250: NPS 26 through NPS 48 standard
No liability or guarantee for the correctness and completeness of the information provided
