What is a pipe flange?

A pipe flange is a protruded rim that help in making a connection between two or more piping equipment. Pipe Flanges can combine or dismantle piping systems or mobile installations to create a transition between dissimilar materials. These Flanges allow room for easy access, cleaning, and inspection. They can be bolted, welded, or screwed following different procedures. There are different Flange Types that are designed to suit different project requirements.

The flange is a ring-shaped device designed to be used as an alternative to welding or threading various piping system components used throughout the piping system. Flanged connections are used as an alternative to welding because they can be easily disassembled for shipping, routine inspection, maintenance, or replacement. Flanged connections are preferred over threaded connections because threading large bore pipe is not an economical or reliable operation. The flange is widely utilized in many piping systems. Flanges are primarily used where a connecting or dismantling joint is needed. These joints may include joining pipe to fittings, valves, equipment, or any other integral component within the piping system.

What is the purpose of a flange in refinery & petrochemical industry?

A flange is used to efficiently connect pipes, tubes, valves, pumps, and other equipment in the refinery and petrochemical industry. Industrial Pipe Flanges can handle different pressure equipment. Their easy maintenance and installation process gives them an edge in this industry. Our company is Industrial Flanges manufacturers who make use of the best material and are available in different dimensions.

What is RF in flange?

An RF flange is a common flange type in the industry and is easy to identify. The flanges have a raised surface that is raised above the bolting circle where a gasket is placed. These Steel Flanges can make use of a wide combination of gasket designs. They ensure strong sealing and can handle higher pressure media in the system.

Type of face flanges

Raised Face Flange vs Flat Face Flange

A flange can be produced either in a raised or flat face specification. A Raised Face Flange has a raised face above the bolting area that allows it to securely seal with a gasket. They ensure a strong sealing and thereby increase the pressure containment capability of the joint.

A Flat Face Flange has a gasket surface that is similar to the face of the bolting circle. These flanges don’t have the same strength as RF flanges and are preferred for lower pressure applications.

What is the advantage of flange joint?

A flange joint is utilized to easily assemble piping equipment in tight spaces. The Flange Joint has excellent flexibility and can be easily maintained without requiring the dismantling of the entire pipe. They securely seal the equipment allowing for rigorous hydraulic movement to take place in the system.

Flange Types

The flanges can be furnished in miscellaneous types including welding neck flange, blind flange, slip on flange, threaded flange, lap joint flange, plate flange, socket welding flange, long welding neck flange, orifice flange, reducing flange, spectacle blind flange, spacer flange, paddle flange, swivel flange, anchor flange, etc.

• Threaded Flanges: – The Threaded flanges have threads under their bore. They are also known as Screwed Flanges. The Thread is used to fix the pipes, which also have threading on their end. They are the easiest to fit Flanges but are not suitable for high-temperature applications. They are also not suggested for high-pressure applications.

• Slip-on Flanges: – Slip-on Flanges are made with holes that match the outer diameter of a pipe. The pipe is passed through the hole and fillet welded from both sides. Low pressure and low-temperature applications are suitable for this kind of flange joint. Slip-on flanges are generally forged and come with a hub. Large sizes are used to connect big bore pipes with storage tanks.

• Socket-Weld Flanges: -Usually used only for Low pressure and temperature applications, Socket-Weld Flanges have a female socket. A pipe is fitted through the female socket in the Flange.

• Lap-Joint Flanges: -Lap-joint flanges are made in two components, which include a stub-end and a loose backing flange. Lap-joint Flange is used for applications that require frequent dismantling. They are designed to not wear from frequent modifications.

• Blind-Flanges: – These Flanges are used as a termination point to a piping system. Blind-Flanges have a blank surface with a bolt point to fit a pipe.

• Spectacle blind flanges: Spectacle Blinds, generally referred to as SB, are Flanges that are applied to systems that require regular separation from their installation. Spectacle blinds are made from two discs, that are attached to each other. One of the discs in SB Flanges is a ring and the other is a solid plate.

• Long weld neck flanges: Long Neck Welding Flanges are made with a circular fitting and a bulging rim around the circumference. They are similar to standard Welding Neck flanges but with a particularly long neck. They are generally not used for pipes but in processing plants.

• Orifice Flange: Orifice Flanges are used to measure the flow rate of liquids or gases in the pipeline. They are used with orifice meters and are suitable for all intensive weld neck flanges with extra machining.

• The Flat-Face flange: Flat Face Flanges frequently are used where casting is used to make mating flange or flanged fitting. Similar to a bolting circle face, they have a gasket surface in the same plane.

• Ring Type Joint: The ring Type Joint flange, generally known as RTJ, is made by putting some grooves cut on their faces. They seal when the Bolts are tightened. These bolts compress the gasket into the grooves. These Flanges are typically used for high pressure and high-temperature services.

• Raised Face: The Raised Face Flanges are high-pressure flanges that have a raised face due to gasket surfaces are raised above the bolting circle face. They are widely used in process plant applications because of their increased pressure containment capability.

• Tongue & Groove: The Touch and groove Flanges consist of two flanges, where one face consists a ring machined onto the flange and the other contains a depression matching the ring on the other. These are commonly found on pump covers and Valve Bonnets.

Pressure Ratings of Flanges

Generally, flanges used in piping system can be categorized in two systems: Metric and US Customary. Forged flanges manufactured to relative ASME standards can be categorized into seven US Customary pressure ratings: Class 150, Class 300, Class 400, Class 600, Class 900, Class 1500, Class 2500. Flanges manufactured to relative EN/BS/DIN standards can be categorized into Metric pressure ratings: PN 2.5, PN 6, PN 10, PN 16, PN25, PN 40, PN 63, PN 100, PN 160, PN 250, PN 320, PN 400. The pressure rating of a flange material is quite temperature-dependent. The maximum allowable pressures of various ferrous and nonferrous metals at maximum applicable temperatures are usually prescribed in each standard.

International Standards for Flanges

• US Standards: ASME B16.5, ASME B16.47, ASME B16.48, ASME B16.36, AWWA C-207, MSS SP 44, API 605, API 6A.
• DIN Standards: DIN 2527, DIN 2573, DIN 2576, DIN 2502, DIN 2503, DIN 2543, DIN 2544, DIN 2545, DIN 2630, DIN 2631, DIN 2632, DIN 2633, DIN 2634, DIN 2635, DIN 2636, DIN 2637, DIN 2638, DIN 2628, DIN 2629, DIN 2627, DIN 2641, DIN 2642, DIN 2652, DIN 2653, DIN 2655, DIN 2656, DIN 2673, DIN 2674, DIN 2675, DIN 2676, DIN 2558, DIN 2561, DIN 2565, DIN 2566, DIN 2567, DIN 2568, DIN 2569, DIN 28115, DIN 86029, DIN 86030.
• BS Standards: BS 4504, BS 10, BS 3293, BS EN 1092-1.
• Italian Standards: UNI 2276, UNI 2277, UNI 2278, UNI 6083, UNI 6084, UNI 2280, UNI 2281, UNI 2282, UNI 2283, UNI 2284, UNI 2253, UNI 2254, UNI 6091, UNI 6092, UNI 6093, UNI 6094, UNI 6095, UNI 6088, UNI 6089, UNI 6090.
• ISO Standards: ISO 9624, ISO 7005-1.
• Australian Standards: AS/NZS 4331.1, AS 4087, AS 2129 Table D, Table E.
• Norwegian Standards: NS 2545, NS 2546, NS 2547, NS 2525, NS 2526, NS 2527, NS 2529, NS 2537, NS 2538, NS 25239, NS 2542, NORSOK L-005.
• Other Standards: GOST 12820-80, GOST 12821-80, MSZ flange, NFE 29203, VSM 18695, VSM 18696, VSM 18697, VSM 18716, VSM 18718, VSM 18703, JIS B2220, KS B1503, KS D4308, KS D3578, KS B2332, KS B2333, KS B6216, SABS/ SANS 1123.