What ANSI Flanges Are Commonly Applied Today?

ANSI flanges commonly used today include weld neck, slip-on, blind, threaded, and socket weld flanges. Each serves a specific purpose, from handling high-pressure systems to providing easy installation in low-stress applications.

In this guide, you’ll learn about the different ANSI flange sizes, standards, and their applications in various systems. Keep reading for more details on choosing the right flange for your project.

What Does ANSI Mean?

ANSI stands for the American National Standards Institute. It is a private non-profit organization that oversees the development of consensus standards for various industries, including piping systems.

ANSI’s involvement ensures that your products and systems—such as ANSI flange components—are compatible, safe, and reliable. 

Such flanges are engineered following strict guidelines. They are expected to meet the performance demands of industrial applications. Such compliance allows for a seamless connection between different components.

ANSI flange dimensions are recognized worldwide for standardizing connections. This is why they’re commonly used in high-pressure and high-temperature industries.

ANSI Flanges Available for Different Applications

ANSI flanges are available in various types. Each is designed to serve specific functions within industrial piping systems. The following are the most commonly used types in today’s industries:

Weld Neck Flanges

Known for their strength, these ANSI flanges are ideal for high-pressure applications. Weld neck flanges have a long tapered hub. It reinforces the connection, ensuring durability in stressful environments such as oil refineries and chemical plants.

Blind Flanges

These are the most cost-effective ANSI flanges. Slip-on flanges are typically used in lower-pressure systems. They slip over the pipe’s end and are welded inside and outside.

Threaded Flanges

Ideal for small-diameter pipes, these ANSI flanges allow for easy installation without welding. Threaded flanges work well in low-pressure, non-hazardous applications, such as water lines.

Socket Weld Flanges

Another ANSI flanges commonly used today is the socket weld flange. These flanges can accommodate smaller, high-pressure systems. The pipe is inserted into the flange and welded, making it suitable for chemical and hydraulic applications.

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Different ANSI Flange Standards

ANSI flanges are classified under different standards based on their design, material, and pressure-handling capability. Some of the commonly applied standards include:

• ANSI B16.5: This standard covers pipe flanges and flanged fittings for sizes ranging from ½ inch to 24 inches. Pressure ratings of 150 to 2500 psi fall into this category, too. This is the most widely used standard for ANSI flange applications in the oil, gas, and petrochemical industries.
• ANSI B16.47: This standard applies to large-diameter steel flanges, typically 26 inches and larger. It also covers two pressure classes: Series A (for higher-stress environments) and Series B (for lower-pressure applications).
• ANSI B16.1: This standard focuses on cast iron ANSI flanges and fittings and is commonly used in non-corrosive, low-pressure water and steam applications.

These standards ensure that ANSI flange dimensions and performance are consistent across industries.

ANSI Flange Sizes and ANSI Flange Specifications

The ANSI flange sizes are determined by several factors, including pipe size, pressure class, and material. Standard ANSI flange sizes range from ½ inch to 24 inches for flanges covered under ANSI B16.5, and even larger for ANSI B16.47.

ANSI Flange Dimensions

ANSI flange dimensions are crucial for ensuring the correct fit and performance in a system. Some of the key ANSI flange dimensions include:

• Outside Diameter (OD): The overall diameter of the flange.
• Bolt Circle Diameter (BCD): The distance between the center of the bolt holes.
• Hub Diameter: For weld neck flanges, this refers to the width of the hub that connects to the pipe.

ANSI Flange Pressure Classes

ANSI flange components are categorized by pressure class, with common classes including 150, 300, 600, 900, 1500, and 2500. The pressure class indicates the maximum pressure the flange can withstand at a specified temperature. For instance, a Class 150 ANSI flange is designed for lower-pressure systems. On the other hand, a Class 2500 ANSI flange is built for extreme-pressure applications.

Conclusion

ANSI flanges are crucial components in industrial piping. They offer standardized and reliable connections for pipes and equipment. The commonly used ANSI flanges are weld neck, slip-on, and blind flanges. Each complies with ANSI flange sizes and ANSI flange specs to accommodate both low-pressure water systems and high-stress refineries.
If you are looking to partner with a reliable manufacturer of ANSI flanges, Longan Flange is one of the best options. Longan Flange can supply the perfect product for your system requirements. They guarantee durability, precision, and safety in every application. Contact us today to learn more about how we can support your piping projects.

References

“ANSI Class” Ratings of Pipe Flanges (1)

ANSI Flange Dimensions and Ratings (2)