15 Different Types of Flanges and Their Uses
Published: 26 Nov 2025
In this article, we will discuss what a flange is and the different types of flanges and their uses in a simple and easy way. Flanges are important parts of piping systems because they help connect pipes, valves, pumps, and other equipment safely.
What is a Flange?
A Flange is a mechanical Connecting device used to connect pipes, join equipment, or close piping systems. It provides a strong and leak-proof connection using bolts, gaskets, and proper alignment. Flanges make maintenance, inspection, and cleaning much easier because they can be assembled and disassembled whenever needed. You will find flanges in power plants, oil and gas, water lines, and in many other industries.
Different Types of Flanges & Their Uses
Below are the most widely used flange types along with their applications.
1. Weld Neck Flange
A weld neck flange has a long, tapered neck that provides strong support and smooth flow. It is used in high-pressure and high-temperature systems where strength is essential. The flange is welded to the pipe using a butt weld, creating an extremely strong joint. Its design reduces stress on the pipe and helps prevent leaks. Industries such as oil, gas, and chemical plants use it for safe and reliable performance. This flange is one of the most trusted choices for heavy-duty piping.
2. Long Welding Neck Flange
The long welding neck flange has an extended neck that works like a pipe extension. It replaces the need for a separate nozzle and provides better strength. This design ensures smooth flow and minimizes pressure drop. It is commonly used in pressure vessels, storage tanks, and high-temperature applications. The extra length improves stability and reduces stress. It is ideal for heavy industrial systems requiring strong and reliable connections.
3. Slip-On Flange
A slip-on flange slides easily over the pipe before welding, making installation simple. It needs two fillet welds inside and outside to secure the joint. It is used mostly in low-pressure and low-temperature applications. Slip-on flanges are economical and require less accuracy during installation. They are used in water pipelines, HVAC systems, and general industrial services. Although not as strong as weld neck flanges, they are suitable for non-critical applications.
4. Threaded Flange
A threaded flange connects to a pipe using threads rather than welding. This makes it useful in areas where welding is risky, such as explosive or flammable environments. It is easy to assemble and disassemble, making maintenance quicker. Threaded flanges work best for small pipe sizes and low-pressure systems. They are commonly used in gas lines, steam lines, and temporary piping setups. This flange reduces welding costs and avoids heat-related pipe damage.
5. Socket Weld Flange
A socket weld flange has a socket into which the pipe is inserted before welding. The weld is applied only on the outside, keeping the inner surface smooth. This provides strong joints suitable for high-pressure applications. It is typically used for small pipe sizes up to 2 inches. Socket-weld flanges help maintain proper alignment during installation. They are used in power plants, chemical plants, and high-pressure hydraulic systems.
6. Lap Joint Flange
A Lap Joint Flange is used in piping systems that need frequent dismantling or alignment. It is not welded directly to the pipe but slides over a stub end that is welded to the pipe and is bolted in place. This design allows easy assembly, reduces welding time, and enables flange rotation for proper bolt alignment. Lap joint flanges are ideal for low- to medium-pressure systems, such as chemical, food, or other pipelines requiring regular maintenance.
7. Blind Flange
A blind flange has no center hole and is used to close the end of a pipe or nozzle. It provides a strong seal and can handle high pressures. Blind flanges are often used during the pressure testing of pipeline systems. They allow future expansion by keeping a connection available. These flanges are common in chemical plants, refineries, and water treatment plants. Their strong construction helps isolate sections of the pipeline safely.
8. Orifice Flange
An orifice flange is designed to hold an orifice plate used for flow measurement. It comes with pressure-tapping holes for connecting instruments. This allows accurate monitoring of pressure and flow rates. Orifice flanges are widely used in oil and gas, power plants, and chemical processing. They make maintenance easier because the plate can be removed without disturbing the flanges. These flanges play a key role in process control and system performance.
9. Nipo Flange
A Nipo Flange is a combination of a nipple and a flange welded together. It provides a compact and strong connection for branch pipelines. This all-in-one design reduces the need for multiple fittings. Nipo flanges are ideal for high-pressure services and small pipe sizes. They are used in refineries, petrochemical plants, and high-temperature systems. Their design saves space and improves reliability in complex piping networks.
10. Swivel Flange
Swivel flanges consist of two parts, one of which can rotate freely for easy alignment. They reduce installation stress and simplify assembly in complex systems. These flanges are used in marine, offshore, and subsea pipelines for flexibility. They allow easier maintenance and adjustments in tight or angled installations. Swivel flanges are strong, durable, and safe for high-pressure applications. They are ideal where precise alignment is challenging.
11. Elbow Flange
An elbow flange combines an elbow and a flange in one piece. It helps change the direction of the pipeline while keeping a flanged connection. This saves space and reduces the number of fittings needed. Elbow flanges are used in tight areas where normal elbows and flanges cannot fit easily. They provide smooth flow with reduced turbulence. They are used in power plants, chemical industries, and water distribution systems.
12. Expanding Flange
An expanding flange increases the pipe size gradually from a smaller diameter to a larger one. It helps reduce pressure loss and maintains smooth flow. It is used when equipment outlets and pipeline sizes do not match. Industries use expanded flanges at pump outlets, compressor units, and flow control systems. It reduces the need for additional reducers. Its smooth transition improves system efficiency.
13. Reducing Flange
A reduced flange connects pipes of different diameters within the same joint. It saves installation space and reduces the number of fittings. This flange is useful when equipment connections differ in pipeline size. It works well in moderate-pressure systems. Industries use it in pump suction lines, valve connections, and compact systems. It provides a strong and leak-proof solution for size transitions.
14. Puddle Flange
A Puddle Flange prevents water leakage where pipes pass through concrete walls or slabs. It forms a tight waterproof barrier that protects buildings from seepage. These flanges are commonly used in basements, water tanks, and underground structures. They are easy to install and provide long-lasting sealing. Puddle flanges are essential for protecting structures from moisture damage. They improve safety and extend the life of construction projects.
15. Split Flange
A split flange comes in two separate pieces that are bolted together around the pipe. It is ideal for repair jobs where cutting the pipe is not possible. Split flanges make maintenance quick and easy. They are used in hydraulic systems, industrial equipment, and pipelines. Their design allows installation on existing lines without disassembly. They provide a strong and secure connection while reducing downtime.
Conclusion
In conclusion, in this article, we covered what a flange is and the different types of flanges and their uses in detail. I hope you found this information helpful and easy to understand. If you think this guide can help others, feel free to share it with your friends.
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- Stay Positive
- True Feedback
- Encourage Discussion
- Avoid Spamming
- No Fake News
- Don't Copy-Paste
- No Personal Attacks
