PN16 vs PN25 — When to Step Up Pressure Rating
PN16 is the workhorse for many water and general process lines in EN flange systems. PN25 is selected when design pressure or temperature needs more margin. Flange dimensions differ — do not freely mate PN16 and PN25 without checking the piping spec.
Quick selection
Default many water/HVAC BOQs to PN16. Use PN25 when design pressure requires it. See PN25 vs PN40.
Comparison table
| Factor | PN16 | PN25 |
|---|---|---|
| Nominal rating | 16 bar class (EN) | 25 bar class (EN) |
| Typical services | Water, HVAC, general process | Higher pressure water / process |
| Flange match | EN 1092 PN16 flanges | EN 1092 PN25 flanges |
| Cost / weight | Lower | Higher |
| Buyer action | State PN16 + MOC + ends | State PN25 explicitly on BOQ |
Selection pitfalls
PN is not interchangeable with Class by simple arithmetic.
- Confirm face-to-face and flange OD/PCD for the PN chosen.
- For Class systems, use Class 150/300 guides instead of PN.
RFQ wording that works
- “Gate / butterfly / check, PN16, flanged EN 1092-2, DI / WCB, DN__, qty __.”
- Or: “PN25 butterfly wafer, DI body, SS disc, EPDM, gear.”
FAQ
Can I bolt a PN16 valve to PN25 flanges?
Not as a default practice. Follow piping engineering rules.
Is PN16 the same as Class 150?
Roughly similar for many water duties but not identical.
When is PN40 needed?
Higher pressure process — see PN25 vs PN40.
Does PN change face-to-face?
Face-to-face follows product standards; confirm on the GA.
Related RFQs and hubs
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