The butterfly valve pressure rating shows the maximum pressure a valve can handle at a specific temperature. You can use PN16, PN25, and PN40 when you’re working with European bar-based systems, and it means each number reflects the allowable pressure in bar. A pn16 butterfly valve handles around 16 bar or 232 PSI.
Class 150 follows the ASME system used in North America. It also gives you a clear limit for real operating conditions. A butterfly valve class 150 handles 285 PSI at 100°F, and that number shifts as temperature rises because metal strength changes with heat.
Why Pressure Ratings Matter
Choosing the wrong valve pressure rating creates problems fast. It means the valve may not hold pressure, and that can lead to leaks, unplanned shutdowns, or safety issues.
The pressure rating of butterfly valves changes with body material and operating temperature. Heat reduces metal strength, so the safe working pressure drops as temperatures climb. You can avoid failures by checking the valve’s rating against both the pressure in your system and the heat it will be exposed to.
PN vs Class Rating Systems
ASME uses Class ratings measured in PSI. You can see these in most North American projects. Europe uses PN ratings measured in bar, and it means the number reflects the allowable working pressure at standard conditions.
| Rating System | Common Ratings | Unit | Standard | Region |
| ASME Class | 150, 300, 600 | PSI | ASME B16.34 | North America |
| PN | PN16, PN25, PN40 | bar | EN 12516 | Europe, Asia |
The class 150 butterfly valve pressure rating is close to PN16, but not identical. It means you can’t swap them without checking dimensions and pressure tables.
PN16 Butterfly Valve Specifications
A pn16 butterfly valve handles 16 bar (about 232 PSI) at room temperature. Water treatment plants and HVAC systems use this rating often because it fits typical building and utility pressures.
The pn16 butterfly valve pressure rating works well with cast iron or ductile iron bodies. You can use EPDM seals within this range, and it also means the valve will operate safely from -10°C to 120°C, depending on the seal material.
PN16 vs PN25 Differences
The pn16 vs pn25 comparison shows how wall thickness changes with pressure. PN25 valves handle 25 bar (about 363 PSI) and use stronger, thicker bodies than PN16 valves.
You can choose PN25 when your system runs between 16 and 25 bar. PN16 and PN25 flanges don’t match, because the bolt patterns differ, and that can create alignment issues during installation.
PN40 Butterfly Valves for High Pressure
PN40 butterfly valves handle 40 bar (about 580 PSI) and work in demanding industrial systems. Chemical plants and steam networks use PN40 when they need high pressure and stable performance.
PN40 bodies rely on ductile iron or stainless steel. An 8 butterfly valve pressure rating at PN40 moves a large flow through an 8-inch line, and it means the valve must stay strong under high stress.
Class 150 Specifications
The butterfly valve class 150 rating is the most common in North America. It handles 285 PSI at 100°F, but that drops to 230 PSI at 400°F because heat affects metal strength.
Temperature vs Pressure (Class 150 → PN16 Equivalent)
| Temperature | Class 150 Pressure | PN16 Equivalent |
| 100°F (38°C) | 285 PSI | ~19.6 bar |
| 400°F (204°C) | 230 PSI | ~15.9 bar |
Oil and gas projects use Class 150 frequently. It also means the class 150 butterfly valve pressure rating lines up near PN16, though the two systems are not fully interchangeable.
Temperature Effects on Ratings
Temperature reduces safe working pressure directly. Metals weaken as heat rises, and that can drop the butterfly valve pressure rating faster than many users expect. Manufacturer charts show how pressure limits change with each temperature step.
The butterfly valve surge pressure rating matters too. Startups and shutdowns create water hammer, and those spikes can exceed normal ratings for a moment.
Selecting the Right Rating
Match valve rating to system pressure with room to spare. Systems running at 12 bar need PN16, not PN10 at maximum capacity.
Check that valve ratings match flange ratings through your whole system. Mixing ASME and PN ratings needs adapter flanges.At CTGV, we build butterfly valves for PN16, PN25, PN40, and Class 150 ratings. Our valves meet API 609 and ASME B16.34 standards. Contact us today if you have any confusion about how these ratings may affect the outcome of your project.
