Flanges are used in place of welded connections to facilitate maintenance operations because, unlike other mechanical connectors, they can be removed fast and easily. As a result, they are frequently utilized in temporary or moving installations, disassembling piping systems, transitioning between incompatible materials, and connecting in places that are not suitable for solvent cementing.

They are the most often used mechanical connections because they are cost-effective, simple to understand, reliable, and readily accessible from a variety of manufacturers. Similarly, their moment carrying capability is greater than that of other connectors, making them ideal for systems that experience lateral buckling or pipe wandering as a result of pressure and temperature changes.

What are Flanges on Pipes?
Pipe flanges are essentially bulging edges, collars, rims, or ribs that are used to connect two pipes, a channel, or other fitting equipment. They are available in a variety of configurations and can be engineered to fulfill a variety of application and function requirements, including corrosion resistance and high-temperature operation. They are relatively straightforward to install and have been proven useful in high-pressure plumbing applications.

Prior to shopping for the appropriate flange, it is critical to assess the amount of strength required for the flanged junction, as this will dictate the appropriate piping flange dimensions and type.

Pipe Flange Types
Flanges are classified into six distinct categories. These designs, however, can be adjusted to fulfill the unique purposes and requirements of individual applications. As a result, it is critical to comprehend the pressure at the highlighted junction, the needed strength, and the pipe diameters involved. With the necessary knowledge, an individual can choose from six different sorts of flanges. These include the following:

Welding of Sockets (Socket Weld Flange)
Threaded
On a lap (Lap joint)
Neck welding (Weld neck)
Welding by Slip On Flange (Slip on)
Threaded
Additionally, depending on the application and function, the flanges can be adjusted to produce additional types. These one-of-a-kind designs contain specific requirements and applications, such as decreasing flanges to accommodate size changes and orifice flanges to accommodate orifice mounting. Among the additional instances in this area are the following:

Elboflange
Nipoflange/ Weldoflange
Expander Flange Swivel Flange
Let us review the major characteristics of the various types of flanges.

1. Flange for the Welding Neck
They include a large tapered hub that aids in pressure transfer from the flange to the individual pipe and provides additional strength reinforcement to prevent dishing. Their robust structure increases their strength and stiffness, making them appropriate for temperature and pressure fluctuations, making them perfect for high/low temperature and pressure pipes.

2. Flange with Blind Flange
They are mostly used to seal pipe or valve ends. They feature circular faces and are devoid of central holes, which makes them ideal for blinding pipelines. Similarly, they are engineered to accommodate common channels of varying diameters and have a higher pressure rating than other varieties.

3. Flange with Threaded Holes
They are easier to install than other varieties. They are Threaded Flange into the bore parallel to the exterior threading of the tube and tapered to create a seal between the pipe and the flange. As a result, welding is not required.

They are ideal for small pipes and connections with low pressure. They cannot, however, tolerate extremely low or rapidly shifting temperatures. The flange must function at a temperature of not more than 260° Celsius and not less than 40° Celsius to be effective.

They are most frequently found in galvanized street plumbing and were previously used to manufacture synthetic ammonia. They are not recommended for use in any system that may experience cyclic loading, crevice corrosion, or severe erosion. Additionally, it is critical to avoid using them with bigger weights and high torques.

4. Flange with a slip-on design
This flange design glides over the end of the piping and is then soldered in place. They are simple to install and cost-effective, making them ideal for low-pressure applications. Due to the ease of alignment, further applications include non-purifying compressed air and flowing water.

5. Flange for Lap Joint
Their primary application is on lap joint stub ends on pipes. They are never in contact with the media and freely rotate around the tube, allowing for easy alignment and assembly of bolt holes even after the welds are completed. As a result, they are perfect for systems that require frequent pipe and flange installation. Due to the fact that they do not come into contact with the media, they are more ideal for pipelines carrying corrosive liquids and are the greatest option for preserving nonferrous metals, stainless steel, and other valuable corrosive resistant material.

6. Flange with Socket Weld
They are the most suitable material for high-pressure, small-diameter pipework. Slip-on flanges are larger in size than they are, but their internal pocket allows for smoother fluid flow and a smooth bore. When internally welded, these flanges have a fatigue strength that is 50% more than that of their double-welded slip-on counterparts.

Along with the six primary types of flanges, as previously stated, other special varieties are frequently changed to fit specific tasks and uses. These include the following:

7.Weldoflange
Weldoflanges are a hybrid of weld neck flanges and weldolets. Unlike most flanges, weldoflanges are formed from a single piece of solid forged steel.

8.Nipoflange
Nipoflanges are frequently utilized on branch pipes. It is constructed with a weld neck flange and a forged Nipolet.

9. Flange with Swivel
Swivel flanges are offered in a variety of common configurations, including lap joint, socket, and weld neck. Its primary application is to facilitate bolt hole alignment between dual mating flanges, hence facilitating the installation of large diameter pipelines, such as offshore and subsea pipelines, or pipework in shallow waters.

They are well suited for gas, hydrocarbons, chemicals, oil, and water, as well as other difficult fluids in water management and petrochemical applications.

10.Latroflanges and Elboflanges
They are the least frequently encountered flange Olets. Elboflange is a product of the combination of a letrolet and a flange, whereas latroflange is a product of the combination of a latrolet and a flange. They are advantageous in situations when a pipe must branch at a 45-degree angle.

11. Flange Reducer
As the name implies, a reducing flange is used to reduce the bore of a pipeline between points or to connect pipes to other mechanical devices, such as compressors, pumps, or valves with various intake sizes.

The reducing flange can only be used to reduce the bore of the run pipe by two sizes. If this is insufficient for the purpose, the final alternative solution of a butt weld reducer and a standard flange may be considered. If a decreasing flange can achieve the desired outcome, it is more cost effective.

12.Expanding Flange
They function in the same manner as the reducing flanges. They are advantageous for extending the bore of the pipeline from one location to another. An expanding flange, like a reducing flange, can only enlarge the bore by two sizes.

Pipe flange classification
The most frequently used method of identifying flanges is by their shape. It is critical to remember, however, that there are more classifications for flanges, since these come in useful when durability, functioning, and application are concerned. These include the following:

Brass, alloy steel, cast iron, carbon steel, stainless steel, aluminum, or PVC are all classified according to the material used.
The flat, ring joint, raised, female and male, lap joint, tongue, and groove flange faces are classified.
Classification according to the dimensions of the piping flanges, which may include the pressure rating or nominal size.
Classification according to flange finish, which includes smooth, stock, and serrated flanges.
How flanges work
Flanges have vertical surfaces that are flat or flush with the pipe to which they are connected. Attachment is a mechanical technique that utilizes bolts, adhesives, collars, or welds to link two or more faces.

A flange must fit the equipment or pipe for which it is built due to the attachment requirements. That is why it is critical to verify all conceivable specifications and dimensions to ensure that the item is the correct size, kind, and material.