5.6 types of flanges in piping

Types of Flanges in Piping

Introduction of Flanges

Flanges play a crucial role in the world of piping systems, providing a means to connect pipes, valves, and other components while ensuring a secure and leak-free connection. They are essential for a wide range of applications, from industrial processes to plumbing systems. In this article, we will explore the different types of flanges used in piping, highlighting their unique features and applications.

types of flanges

• Weld Neck Flanges
• Slip-On Flanges
• Blind Flanges
• Socket Weld Flanges
• Lap Joint Flanges

above are main types of flanges.

Weld Neck Flanges

Weld neck flanges are among the most common types of flanges used in piping systems. They have a long tapered hub, which serves to reinforce the connection and provide excellent structural strength. Weld neck flanges are ideal for high-pressure and high-temperature applications, as they distribute stress evenly across the pipe, reducing the risk of leakage. They are commonly used in industries such as oil and gas, petrochemical, and power generation.

Slip-On Flanges

Slip-on flanges feature a slightly larger diameter than the pipe, allowing the pipe to slip into the flange. These flanges are then welded on the inside and outside to provide strength and prevent leakage. Slip-on flanges are convenient to install and are often used in low-pressure applications where the need for a strong joint is not critical. They are widely employed in water supply systems, irrigation, and general plumbing.

Needle valve

Blind Flanges

Blind flanges, as the name suggests, are used to seal the end of a piping system. They have no center bore and are bolted to the flange of the pipe, effectively blocking the flow of fluid. Blind flanges are commonly used for maintenance purposes, where access to the interior of the pipe is required. They also find applications in pressure vessels, where closure is necessary for inspection or cleaning.

Threaded Flanges

Threaded flanges have internal threads that match the external threads of pipes, allowing them to be screwed together. They provide a strong and reliable connection and are suitable for low-pressure applications. Threaded flanges are commonly used in small-diameter piping systems, plumbing, and fire protection systems.

Socket Weld Flanges

Socket weld flanges are similar to slip-on flanges but have a socket-like recess on the inside to accommodate the pipe. The pipe is inserted into the socket, and fillet welding is done around the perimeter to create a robust joint. Socket weld flanges are typically used in small-diameter high-pressure piping systems, such as steam lines and chemical processes ( blind flanges).

Lap Joint Flanges

Lap joint flanges consist of two components: a stub end and a loose backing flange. The stub end is welded to the pipe, while the backing flange can freely rotate around it. This design allows for easy alignment during installation. Lap joint flanges are primarily used in systems where frequent dismantling and maintenance are required, such as in pipelines handling corrosive fluids or those subject to expansion and contraction.

Orifice Flanges

Orifice flanges are designed specifically for measuring flow rates or controlling the flow of fluids. They have concentric or eccentric openings (known as orifice plates) that create a pressure drop, allowing for accurate measurement.(types of flanges in piping) Orifice flanges find applications in industries such as oil and gas, chemical, and water treatment, where precise flow control is essential.

Pressure drop across Orifice Plate

Read Above article to calculate pressure drop in orifice plate.

Selection of Flanges in Piping

Choosing the right flange for a specific piping application is crucial to ensure proper functionality, safety, and longevity of the system. Here are some key factors to consider when selecting flanges:

1. Pressure and Temperature Ratings: Flanges must be able to withstand the pressure and temperature conditions of the piping system. Refer to industry standards and specifications to determine the appropriate pressure and temperature ratings required for the flanges. It is essential to select flanges that can handle the maximum operating conditions without compromising the integrity of the system.
2. Material Compatibility: Consider the compatibility of flange materials with the fluid or gas being transported. Factors such as corrosiveness, acidity, and temperature of the medium should be taken into account. Common flange materials include carbon steel, stainless steel, alloy steel, and various other alloys. Consult with material experts or refer to corrosion resistance charts to ensure the selected flange material is suitable for the specific application (types of flanges in piping).
3. Flange Facing and Gasket Selection: The type of flange facing plays a significant role in achieving a leak-free connection. Raised face (RF), flat face (FF), and ring type joint (RTJ) are some of the common flange face configurations. The choice of gasket material, such as rubber, graphite, or PTFE, should be compatible with the flange facing and the fluid or gas being transported. Gaskets help create a seal between flange surfaces, preventing leaks.
4. Size and Dimensions: Select flanges that are compatible with the pipe size and dimensions. Flanges come in various sizes, ranging from small diameter pipes to large industrial pipelines. Ensure the flange size matches the pipe size and the associated fittings, valves, and equipment.
5. Flange Standards: Adhere to industry standards such as ASME B16.5, ASME B16.47, and API 605, which provide specifications and guidelines for flange dimensions, materials, ratings, and testing. Following these standards ensures interchangeability and compatibility between different manufacturers and systems.
6. Application Considerations: Consider the specific requirements of the piping system and the environment in which it operates. Factors such as vibration, expansion and contraction, seismic activity, and special service conditions (e.g., high purity applications, hygienic processes) may influence the choice of flange type and design. Consult with engineering experts to assess the suitability of flanges for the intended application.
7. Cost and Availability: Evaluate the cost-effectiveness and availability of the chosen flanges. Consider factors such as procurement costs, maintenance requirements, and the availability of spare parts. Balancing cost considerations with performance and quality is crucial for optimal flange selection.

flanges standard

Flanges are available in various standards that define their dimensions, materials, pressure ratings, and other specifications. Some of the commonly used flange standards include:

1. ANSI/ASME B16.5: This standard, published by the American National Standards Institute (ANSI) and the American Society of Mechanical Engineers (ASME), covers steel pipe flanges and flanged fittings from NPS 1/2 to NPS 24. It includes pressure-temperature ratings, dimensions, tolerances, and marking requirements for various flange types.
2. ANSI/ASME B16.47: Also known as Large Diameter Steel Flanges, this standard provides information on large diameter flanges (NPS 26 through NPS 60) in pressure classes 75, 150, 300, 400, 600, and 900.
3. ISO 7005: The International Organization for Standardization (ISO) standardizes flange dimensions and pressure-temperature ratings for steel and steel-alloy flanges in various classes.
4. DIN EN 1092-1: This European standard specifies flange dimensions and types for steel flanges used in pressure and temperature applications.
5. JIS B2220: The Japanese Industrial Standards (JIS) specify the dimensions, materials, and pressure ratings for steel pipe flanges in Japan.
6. BS 4504: The British Standard 4504 covers circular flanges for pipes, valves, and fittings in various materials and pressure classes.
7. AS 2129: This Australian standard specifies flange dimensions for flanges in steel, cast iron, and copper-nickel materials.
8. MSS SP-44: This standard published by the Manufacturers Standardization Society (MSS) provides guidelines for steel pipeline flanges in sizes NPS 22 through NPS 48.
9. API 6A: The American Petroleum Institute (API) standardizes flanges used in oil and gas applications, particularly for wellhead and Christmas tree equipment.

These are some of the widely recognized flange standards used globally. When selecting flanges for a specific application, it is crucial to refer to the appropriate standard to ensure compatibility, safety, and compliance with industry requirements.

People also ask

Q: What are the different types of flanges?

A: Flanges are mechanical components used to connect pipes, valves, pumps, and other equipment to form a piping system. There are several types of flanges, some of which include:

1. Weld Neck Flange
2. Slip-On Flange
3. Socket Weld Flange
4. Threaded Flange
5. Blind Flange
6. Lap Joint Flange
7. Orifice Flange
8. Spectacle Blind Flange
9. Expander Flange
10. Reducing Flange
11. Groove & Tongue Flange
12. Ring Joint Flange
13. Flat Face Flange
14. Raised Face Flange

Q: What are the 13 types of flanges?

A: The 13 types of flanges include:

1. Weld Neck Flange
2. Slip-On Flange
3. Socket Weld Flange
4. Threaded Flange
5. Blind Flange
6. Lap Joint Flange
7. Orifice Flange
8. Spectacle Blind Flange
9. Expander Flange
10. Reducing Flange
11. Groove & Tongue Flange
12. Ring Joint Flange
13. Flat Face Flange
14. Raised Face Flange

Q: How many types of pipe flanges are there?

A: There are several types of pipe flanges available for different applications. The number of types can vary based on the classification and specific requirements, but commonly used flanges include Weld Neck Flange, Slip-On Flange, Socket Weld Flange, Threaded Flange, Blind Flange, and Lap Joint Flange.

Q: What are the two main types of flanges?

A: The two main types of flanges are:

1. Weld Neck Flange: This type of flange is designed to be butt-welded to the pipe. It has a long tapered neck that provides excellent reinforcement to the joint and is suitable for high-pressure and high-temperature applications.
2. Slip-On Flange: Slip-On flanges are slipped over the pipe and then welded in place. They are easy to align and are commonly used for low-pressure applications.

These two types are widely used in various piping systems and industries for connecting pipes and equipment securely.

How do you size a pipe flange?

Sizing a pipe flange involves determining the appropriate dimensions and specifications of the flange to ensure it fits and functions correctly in the piping system. The sizing process typically involves the following steps:

1. Identify the Pipe Size: Determine the size of the pipe to which the flange will be attached. Pipe size is usually specified in inches and is based on the inner diameter (ID) or nominal bore (NB) of the pipe.
2. Select the Flange Type: Choose the appropriate flange type based on the requirements of the piping system, such as pressure rating, temperature, and the type of connection needed (weld neck, slip-on, socket weld, etc.).
3. Determine the Flange Dimensions: Flanges are available in various standard dimensions, such as ANSI, ASME, DIN, or EN standards. Each standard has specific dimensions for flange outer diameter (OD), inner diameter (ID), bolt hole diameter, and thickness. Refer to the relevant standard to get the required dimensions.
4. Calculate the Flange Class/Pressure Rating: The pressure rating or class of the flange depends on the design pressure of the piping system. It is essential to select a flange with an appropriate pressure rating to ensure the system’s safety and integrity.
5. Consider Flange Facing: Flanges can have different facing types, such as raised face (RF), flat face (FF), or ring-type joint (RTJ). The facing type should match the requirements of the gasket and the connecting equipment.
6. Bolt and Gasket Sizing: Determine the size and number of bolts required for the flange based on the flange size and pressure rating. Select a suitable gasket material and size that complements the flange and pipe dimensions and is compatible with the system’s operating conditions.
7. Check for Compatibility: Ensure that the selected flange size, class, and type are compatible with the pipe and other connecting components in the system.
8. Compliance with Standards: Verify that the selected flange complies with applicable industry standards and codes, such as ASME B16.5 or ASME B16.47, for safety and quality assurance.
9. Consult Engineering References: For critical applications or complex systems, it’s advisable to consult engineering references, handbooks, or seek the expertise of a professional engineer to ensure accurate flange sizing.

It’s crucial to remember that proper flange sizing is essential to maintaining the integrity and efficiency of the piping system. Incorrectly sized flanges can lead to leaks, system failures, or safety hazards. Always follow industry best practices and guidelines when sizing and selecting pipe flanges.

Conclusion

The world of piping systems relies heavily on the use of flanges for secure and leak-free connections. Each type of flange discussed in this article serves specific purposes, catering to different pressure, temperature, and application requirements. By understanding the characteristics and applications of various flange types like weld neck, slip-on, blind, threaded, socket weld, lap joint, and orifice flanges, professionals can make informed decisions when it comes.

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