| Flange NPS | Inside | Outside | Bolt Circle | Raised Face | Raised Face | H | H1 | Raised Face | T1 | Flat Face | Bolt Hole | No. of |
| Diameter | Diameter | (BC) | (R) | (RF) | Thickness (T) | Thickness (T2) | (B) | Bolt Holes | ||||
| 1/2″ | 0.55″ | 5.25″ | 3.50″ | 1.38″ | .250″ | 1.69″ | 0.84″ | 3.13″ | 1.19″ | 2.88″ | 0.88″ | 4 |
| 3/4″ | 0.74″ | 5.50″ | 3.75″ | 1.69″ | .250″ | 2.00″ | 1.05″ | 3.38″ | 1.25″ | 3.13″ | 0.88″ | 4 |
| 1″ | 0.96″ | 6.25″ | 4.25″ | 2.00″ | .250″ | 2.25″ | 1.32″ | 3.75″ | 1.38″ | 3.50″ | 1.00″ | 4 |
| 1-1/4″ | 1.28″ | 7.25″ | 5.13″ | 2.50″ | .250″ | 2.88″ | 1.66″ | 4.00″ | 1.50″ | 3.75″ | 1.13″ | 4 |
| 1-1/2″ | 1.50″ | 8.00″ | 5.75″ | 2.88″ | .250″ | 3.13″ | 1.90″ | 4.63″ | 1.75″ | 4.38″ | 1.25″ | 4 |
| 2″ | 1.94″ | 9.25″ | 6.75″ | 3.63″ | .250″ | 3.75″ | 2.38″ | 5.25″ | 2.00″ | 5.00″ | 1.13″ | 8 |
| 2-1/2″ | 2.32″ | 10.50″ | 7.75″ | 4.13″ | .250″ | 4.50″ | 2.88″ | 5.88″ | 2.25″ | 5.63″ | 1.25″ | 8 |
| 3″ | 2.90″ | 12.00″ | 9.00″ | 5.00″ | .250″ | 5.25″ | 3.50″ | 6.88″ | 2.63″ | 6.63″ | 1.38″ | 8 |
| 4″ | 3.83″ | 14.00″ | 10.75″ | 6.19″ | .250″ | 6.50″ | 4.50″ | 7.75″ | 3.00″ | 7.50″ | 1.63″ | 8 |
| 5″ | 4.81″ | 16.50″ | 12.75″ | 7.31″ | .250″ | 8.00″ | 5.56″ | 9.25″ | 3.63″ | 9.00″ | 1.88″ | 8 |
| 6″ | 5.76″ | 19.00″ | 14.50″ | 8.50″ | .250″ | 9.25″ | 6.63″ | 11.00″ | 4.25″ | 10.75″ | 2.13″ | 8 |
| 8″ | 7.63″ | 21.75″ | 17.25″ | 10.63″ | .250″ | 12.00″ | 8.63″ | 12.75″ | 5.00″ | 12.50″ | 2.13″ | 12 |
| 10″ | 9.75″ | 26.50″ | 21.25″ | 12.75″ | .250″ | 14.75″ | 10.75″ | 16.75″ | 6.50″ | 16.50″ | 2.63″ | 12 |
| 12″ | 11.75″ | 30.00″ | 24.38″ | 15.00″ | .250″ | 17.38″ | 12.75″ | 18.50″ | 7.25″ | 18.25″ | 2.88″ | 12 |
Here are the approximate dimensions for a Class 2500 Welding Neck Flange according to ASME B16.5 standards, in inches:
Nominal Pipe Size (NPS): Ranges from 1/2 inch (DN 15) to 24 inches (DN 600) and larger.
Outside Diameter (OD): Varies with NPS. For example, the OD of a 1/2-inch flange is approximately 7.25 inches, while the OD of a 24-inch flange is around 43.75 inches.
Bolt Circle Diameter (BCD): This dimension increases with the size of the flange. For instance, the BCD of a 1/2-inch flange is approximately 6.25 inches, while the BCD of a 24-inch flange is around 40.75 inches.
Number of Bolt Holes: The number of bolt holes varies depending on NPS. Smaller sizes may have fewer bolt holes (e.g., 4), while larger sizes may have more (e.g., 20).
Bolt Hole Diameter: The diameter of the bolt holes varies with NPS. For example, the bolt hole diameter for a 1/2-inch flange is approximately 1.13 inches.
Hub Diameter: The diameter of the raised face at the base of the flange increases with the size of the flange.
Overall Length Through Hub (LTH): This dimension, which is the distance from the face of the flange to the end of the hub, also increases with the size of the flange.
Flange Thickness: The thickness of the flange varies based on the pressure class.
Please remember that these are approximate dimensions, and specific dimensions may vary based on the manufacturer and the standards being followed. For precise and detailed dimensions, it's recommended to refer to the ASME B16.5 standard or consult the manufacturer's specifications for the specific flange size and class.
