16 inch Class 150 flange dimensions
ASME B16.5 Class 150 flange dimensions for 16 inch (DN 400) 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 | 16" (DN 400) |
| Pipe OD (bore end) | 406.4 mm |
| Flange outside diameter | 595 mm (23.43 in) |
| Minimum thickness (incl. 1.6 mm RF) | 35.0 mm (1.38 in) |
| Bolt circle diameter (PCD) | 539.8 mm (21.25 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 16" Class 150 joint needs 16 stud bolts of 1" diameter with 32 heavy hex nuts and one gasket.
Class 150 vs Class 300 — 16"
| Dimension | Class 150 | Class 300 |
|---|---|---|
| OD | 595 mm | 650 mm |
| Thickness | 35.0 mm | 55.6 mm |
| Bolt circle | 539.8 mm | 571.5 mm |
| Bolts | 16 × 1" | 20 × 1-1/4" |
Class 150 and Class 300 flanges do not bolt together — see 16" Class 300.
Frequently asked questions
What is the OD of a 16 inch Class 150 flange?
595 mm (23.43 in) per ASME B16.5.
How many bolts does a 16 inch Class 150 flange have?
16 bolts of 1 inch diameter in 1.12 inch holes on a 539.8 mm bolt circle.
What is the thickness of a 16 inch Class 150 flange?
The minimum flange thickness is 35.0 mm, including the 1.6 mm raised face.
Last updated 2026-11-02