What are Valve Pressure Ratings and Connection Standards?
As a company that has proudly served over 950 customers in 89 countries since 2005, we want to share our expertise with you. Our goal is to provide clear, practical information that empowers you to make every selection with confidence.
01. Decoding Valve Pressure Ratings – The Heart of System Safety
1. Getting to Know the Lingo: Common Pressure Rating Units
In a global marketplace, you'll come across a few different ways pressure ratings are expressed. Let's break them down:
- PN (Pression Nominale / Nominal Pressure): You'll see this often in European standards (like DIN, EN, ISO). The number that follows "PN" gives you the approximate pressure in Bar that the valve can handle at room temperature (usually around 20°C or 68°F). For example, a
PN16valve has a nominal pressure rating of 16 Bar. - Class: This is the standard you'll find in the American system (ANSI/ASME), often written as "Class 150" or "150LB." It’s important to know that the number is not a direct measure of PSI. It's more of a rating category. The actual pressure a valve can handle depends on its material and the operating temperature. For instance, a Class 150 carbon steel valve can handle about 285 PSI at ambient temperatures, but this capacity decreases as the temperature rises.
- Bar & PSI (Pounds per Square Inch): These are the fundamental units of pressure.
- 1 Bar ≈ 14.5 PSI
- 1 MPa (Megapascal) = 10 Bar = 145 PSI
2. A Handy Conversion Reference
While there isn't a perfect mathematical formula to convert between PN and Class (because they are based on different standards, temperatures, and materials), this quick reference chart is a great starting point for engineers and purchasers. It's especially useful for EPC contractors and wholesalers who work with both European and American products.
| American Standard (ASME) | European Standard (DIN/ISO) | Approx. Pressure (Bar) | Approx. Pressure (PSI) |
|---|---|---|---|
| Class 150 (150LB) | PN 20 | 20 | 290 |
| Class 300 (300LB) | PN 50 | 50 | 725 |
| Class 400 (400LB) | PN 68 | 68 | 986 |
| Class 600 (600LB) | PN 110 | 110 | 1595 |
| Class 900 (900LB) | PN 150 | 150 | 2175 |
| Class 1500 (1500LB) | PN 260 | 260 | 3770 |
| Class 2500 (2500LB) | PN 420 | 420 | 6090 |
A friendly reminder: This table is for initial guidance only. For a precise selection, you should always consult the official Pressure-Temperature (P-T) charts in the relevant standard (like ASME B16.34). This will tell you the exact allowable pressure for a specific material at your actual operating temperature.
3. How to Choose Based on Your System's Design Pressure
The golden rule is simple: The valve's pressure rating must be greater than or equal to your pipeline's design pressure.
- Step 1: Know your numbers. Find out the design pressure and operating temperature of your system. This is the most important information you can have.
- Step 2: Think about a safety buffer. If your system experiences pressure fluctuations (like from pumps starting and stopping, or potential water hammer), it’s wise to choose a valve with the next rating up. This adds a welcome safety margin.
- Step 3: Check the P-T charts. Based on your operating temperature, let's make sure the valve is still up to the task. The FleyendaFlow team is always here to help you check the P-T rating for a specific valve.
- Step 4: Talk to us! When in doubt, just ask. Share your system's design parameters with a FleyendaFlow sales engineer. We're happy to help you find that perfect balance between safety and cost-effectiveness.
02. Connection Standards – Ensuring a Perfect Fit
How a valve connects to your pipe is just as important as its pressure rating. Choosing the right connection standard ensures a smooth installation and a reliable, leak-free seal.
At FleyendaFlow, we offer a variety of connection types to suit different industries and regions all over the world.
1. The Main Ways to Connect
- Flanged: This is the most common connection in industrial settings. The valve and pipe have matching flanges that are bolted together with a gasket in between.
- Why people like it: It's easy to install, remove, and maintain. Perfect for almost any pipe size or pressure.
- Where you'll see it: Oil & Gas, Chemical, Water & Wastewater, Power Plants—you name it.
- Threaded: Typically used for smaller pipes, these valves screw directly onto the pipe.
- Why people like it: Quick, easy, and cost-effective.
- Where you'll see it: HVAC, automated irrigation systems, general plumbing.
- Welded: For a permanent, super-secure connection, the valve is welded directly to the pipeline. The main types are Butt Weld (BW) and Socket Weld (SW).
- Why people like it: It offers the strongest connection and best seal, making it ideal for high-pressure and high-temperature applications.
- Where you'll see it: Power generation, biofuel & ethanol plants, pharmaceuticals, and other demanding environments.
2. The Key Connection Standards
Different parts of the world use different standards, which define critical dimensions like the flange size, the number and size of bolt holes, the type of sealing face, and more. A mismatch here means the valve simply won't fit.
- ANSI / ASME (American): The dominant standard in North America. Key specs are
ASME B16.5for flanges andASME B16.34for valves. - DIN (German): Widely used across Europe. The key spec is
EN 1092-1(which replaced the olderDIN 2501) and defines PN-rated flanges. - JIS (Japanese): Common in Japan and other parts of Asia.
- GB (Guobiao): The national standard used for projects in China.
3. How do you choose the right standard?
It's refreshingly simple: Your valve's connection standard must match your pipeline's flange standard.
When you request a quote or place an order with us, please let us know what standard your system uses (for example: "ASME B16.5 Class 150 RF" or "EN 1092-1 PN16"). This ensures the FleyendaFlow valve we send you will be a perfect match for your job site, saving you from costly delays and headaches.
02. Fleyenda Here to Help
Understanding pressure ratings and connection standards is the key to sourcing the right valve for the job. We hope this guide has made the selection process feel a little less complicated and a lot more straightforward.
At FleyendaFlow, we're more than just a manufacturer. We see ourselves as your partner. With a dedicated R&D department, experienced production teams, and a helpful sales force—backed by our experience across 40+ industries—we're here to offer one-stop sourcing services and custom valve solutions. Our products are certified to meet ROHS, CE, CCC, and FDA standards, giving you peace of mind.
Whether you're an EPC contractor looking for a reliable partner for a complex project or a wholesaler wanting to streamline your valve supply chain from China, FleyendaFlow is a choice you can trust.
Have a question?
Reach out to our team today for expert technical support and a friendly quote!