14 inch Class 150 flange dimensions
ASME B16.5 Class 150 flange dimensions for 14 inch (DN 350) 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 | 14" (DN 350) |
| Pipe OD (bore end) | 355.6 mm |
| Flange outside diameter | 535 mm (21.06 in) |
| Minimum thickness (incl. 1.6 mm RF) | 33.4 mm (1.31 in) |
| Bolt circle diameter (PCD) | 476.3 mm (18.75 in) |
| Number of bolt holes | 12 |
| 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 14" Class 150 joint needs 12 stud bolts of 1" diameter with 24 heavy hex nuts and one gasket.
Class 150 vs Class 300 — 14"
| Dimension | Class 150 | Class 300 |
|---|---|---|
| OD | 535 mm | 585 mm |
| Thickness | 33.4 mm | 52.4 mm |
| Bolt circle | 476.3 mm | 514.4 mm |
| Bolts | 12 × 1" | 20 × 1-1/8" |
Class 150 and Class 300 flanges do not bolt together — see 14" Class 300.
Frequently asked questions
What is the OD of a 14 inch Class 150 flange?
535 mm (21.06 in) per ASME B16.5.
How many bolts does a 14 inch Class 150 flange have?
12 bolts of 1 inch diameter in 1.12 inch holes on a 476.3 mm bolt circle.
What is the thickness of a 14 inch Class 150 flange?
The minimum flange thickness is 33.4 mm, including the 1.6 mm raised face.
Last updated 2026-11-02