10 inch Class 300 flange dimensions
ASME B16.5 Class 300 flange dimensions for 10 inch (DN 250) pipe. The same bolting dimensions apply to weld neck, slip-on, blind, socket weld, threaded and lap joint flanges of this size and class.
| Nominal size | 10" (DN 250) |
| Pipe OD (bore end) | 273.1 mm |
| Flange outside diameter | 445 mm (17.52 in) |
| Minimum thickness (incl. 1.6 mm RF) | 46.1 mm (1.81 in) |
| Bolt circle diameter (PCD) | 387.4 mm (15.25 in) |
| Number of bolt holes | 16 |
| Bolt hole diameter | 1.12 in (28.4 mm) |
| Stud bolt diameter | 1" UNC |
| Raised face height | 1.6 mm (1/16 in) |
A complete 10" Class 300 joint needs 16 stud bolts of 1" diameter with 32 heavy hex nuts and one gasket.
Class 300 vs Class 150 — 10"
| Dimension | Class 300 | Class 150 |
|---|---|---|
| OD | 445 mm | 405 mm |
| Thickness | 46.1 mm | 28.6 mm |
| Bolt circle | 387.4 mm | 362.0 mm |
| Bolts | 16 × 1" | 12 × 7/8" |
Class 300 and Class 150 flanges do not bolt together — see 10" Class 150.
Frequently asked questions
What is the OD of a 10 inch Class 300 flange?
445 mm (17.52 in) per ASME B16.5.
How many bolts does a 10 inch Class 300 flange have?
16 bolts of 1 inch diameter in 1.12 inch holes on a 387.4 mm bolt circle.
What is the thickness of a 10 inch Class 300 flange?
The minimum flange thickness is 46.1 mm, including the 1.6 mm raised face.
Last updated 2026-11-02