Understanding how to read and interpret flange pressure class é essencial para engenheiros, especialistas em compras, e instaladores que trabalham em sistemas de dutos. Classe de pressão do flange, often referred to as classificação de pressão, defines how much internal pressure a flange can handle safely at a given temperature.

Neste artigo, we’ll break down what pressure class means, how it is labeled, how temperature affects it, and how to choose the right flange for your application. Whether you’re working with ASME, EN, or AWWA standards, knowing how to read pressure classes is a basic yet critical skill.

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What Is Flange Pressure Class?

UM flange pressure class indicates the maximum pressure a flange can withstand under specific conditions. It is represented by a numeric designation, como:

• Aula 150

• Aula 300

• Aula 600

• Aula 900

• Aula 1500

• Aula 2500

These numbers do not directly mean PSI (pounds per square inch). Em vez de, they relate to a set of pressure-temperature charts defined by international standards like ASME B16.5 ou ASME B16.47.

Por exemplo, uma aula 150 flange made from carbon steel may have a maximum pressure rating of 285 PSI at 100°F, but this rating will drop at higher temperatures.

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How to Read a Flange Pressure Class Label

When you look at a flange or its documentation, you may see a marking such as:

“ASME B16.5 2” CL300 A105”

This tells you:

• ASME B16.5 – the flange standard used

• 2″ – the nominal pipe size (NPS)

• CL300 – the pressure class (Aula 300)

• A105 – the material grade (aço carbono)

O CL300 here means the flange is rated as Class 300, and its pressure-temperature limits are defined in ASME tables based on the material A105.

No sasa oblonga, all our flanges are clearly stamped with pressure class, tamanho, padrão, and material for full traceability and compliance.

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Why Pressure Class Depends on Temperature

One of the most important things to remember is that flange pressure class is temperature-dependent.

Por exemplo, um Aula 300 flange in A105 carbon steel can handle:

• 570 PSI at 100°F

• 370 PSI at 500°F

• 190 PSI at 1000°F

À medida que a temperatura aumenta, metal weakens, and pressure capacity drops. That’s why material selection and operating conditions are just as important as the class rating.

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Different Standards Use Different Class Systems

Most flange pressure ratings follow specific standards, incluindo:

• ASME B16.5 / B16.47

Used in oil, gás, químico, e tubulações industriais. Pressure classes range from 150 para 2500.

• EN 1092-1

European standard that uses Classificações PN (por exemplo, PN10, PN16, PN40), which correspond to pressure ratings in bar.

• AWWA C207

Used in waterworks. Usos Classes B, D, E, F instead of numbers like ASME. Classe D, por exemplo, handles up to 175 PSI.

If you’re unsure which standard to use, the experts at sasa oblonga can help match your application with the correct flange type and pressure rating.

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How to Choose the Right Pressure Class

Here are simple steps to read and choose the right pressure class for your project:

1. Know Your Operating Pressure and Temperature

Always check the maximum pressure and temperature your system will experience.

2. Determine the Flange Material

Different materials like carbon steel, aço inoxidável, or alloy steel perform differently at high temperatures.

3. Refer to Standard Pressure-Temperature Charts

Use ASME or EN charts to find the pressure limit for your material at the operating temperature.

4. Select the Correct Class

Choose a class that offers a pressure limit higher than your system’s pressure at the working temperature.

5. Verify Compatibility

Ensure the flange class matches the pipe schedule, junta, parafusos, and mating flange.

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Common Pressure Class Examples

• Aula 150 – Suitable for low-pressure water, AVAC, or general industrial use.

• Aula 300 – Used in systems with moderate pressure such as steam lines and chemical plants.

• Aula 600 e acima – Required for high-pressure systems, refinarias, or critical services.

Choosing an unnecessarily high class increases cost and weight. Choosing too low is a safety risk.

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Conclusão

Reading and understanding flange pressure class is fundamental to building safe, à prova de vazamentos, and compliant piping systems. By recognizing class labels, consulting temperature-pressure charts, and selecting the right material, you can avoid installation problems and ensure long-term performance.

Fabricantes como sasa oblonga provide full documentation, teste de pressão, and expert support to help you choose the right flange every time. Whether your system runs at 150 PSI or 1500 PSI, sasa oblonga delivers precision-engineered flanges that meet or exceed global standards.