Product Code Database
A flange is a protruded ridge, lip or rim, either external or internal, that serves to increase shear strength (as the flange of a steel beam such as an I-beam or a T-beam); for easy attachment/transfer of contact force with another object (as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera); or for stabilizing and guiding the movements of a machine or its parts (as the inside flange of a railroad car or tram train wheel, which keep the wheels from derailment the rail profile). Flanges are often attached using bolts in the pattern of a bolt circle.
Flanges play a pivotal role in piping systems by allowing easy access for maintenance, inspection, and modification. They provide a means to connect or disconnect pipes and equipment without the need for welding, which simplifies installation and reduces downtime during repairs or upgrades. Additionally, flanges facilitate the alignment of pipes, ensuring a proper fit and minimizing stress on the system.
Although the word 'flange' generally refers to the actual raised rim or lip of a fitting, many flanged plumbing fittings are themselves known as flanges.
Common flanges used in plumbing are the Surrey flange or Danzey flange, York flange, Sussex flange and Essex flange. Surrey and York flanges fit to the top of the hot water tank allowing all the water to be taken without disturbance to the tank. They are often used to ensure an even flow of water to showers. An Essex flange requires a hole to be drilled in the side of the tank.
There is also a Warix flange which is the same as a York flange but the shower output is on the top of the flange and the vent on the side. The York and Warix flange have female adapters so that they fit onto a male tank, whereas the Surrey flange connects to a female tank.
A closet flange provides the mount for a toilet.
There are many different flange standards to be found worldwide. To allow easy functionality and interchangeability, these are designed to have standardised dimensions. Common world standards include ASA/ASME (USA), PN/DIN (European), BS10 (British/Australian), and JIS/KS (Japanese/Korean). In the USA, the standard is ASME B16.5 (ANSI stopped publishing B16.5 in 1996). ASME B16.5 covers flanges up to 24 inches size and up to pressure rating of Class 2500. Flanges larger than 24 inches are covered in ASME B16.47.
In most cases, standards are interchangeable, as most local standards have been aligned to ISO standards; however, some local standards still differ. For example, an ASME flange will not mate against an ISO flange. Further, many of the flanges in each standard are divided into "pressure classes", allowing flanges to be capable of taking different pressure ratings. Again these are not generally interchangeable (e.g. an ASME 150 will not mate with an ASME 300).ASME B16.5
These pressure classes also have differing pressure and temperature ratings for different materials. Unique pressure classes for piping can also be developed for a process plant or power generating station; these may be specific to the corporation, engineering procurement and construction (EPC) contractor, or the process plant owner. The ASME pressure classes for flat-face flanges are Class 125 and Class 250. The classes for ring-joint, tongue and groove, and raised-face flanges are Class 150, Class 300, Class 400 (unusual), Class 600, Class 900, Class 1500, and Class 2500.
The flange faces are also made to standardized dimensions and are typically "flat face", "raised face", "tongue and groove", or "ring joint" styles, although other obscure styles are possible.
Flange designs are available as "weld neck", "slip-on", "lap joint", "socket weld", "Threaded pipe", and also "blind".
The gasket type and Screw type are generally specified by the standard(s); however, sometimes the standards refer to the ASME Boiler and Pressure Vessel Code (B&PVC) for details (see ASME Code Section VIII Division 1 – Appendix 2). These flanges are recognized by ASME Pipe Codes such as ASME B31.1 Power Piping, and ASME B31.3 Process Piping.
Materials for flanges are usually under ASME designation: SA-105 (Specification for Carbon Steel Forgings for Piping Applications), SA-266 (Specification for Carbon Steel Forgings for Pressure Vessel Components), or SA-182 (Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service). In addition, there are many "industry standard" flanges that in some circumstance may be used on ASME work.
The product range includes SORF, SOFF, BLRF, BLFF, WNRF (XS, XXS, STD and Schedule 20, 40, 80), WNFF (XS, XXS, STD and Schedule 20, 40, 80), SWRF (XS and STD), SWFF (XS and STD), Threaded RF, Threaded FF and LJ, with sizes from 1/2" to 16". The bolting material used for flange connection is Threaded rod mated with two nut (washer when required). In petrochemical industries, ASTM A193 B7 STUD and ASTM A193 B16 stud bolts are used as these have high tensile strength.
| Weld-neck flange | Type 11 | DIN 2627 – DIN 2638 |
| Blind flange | Type 05 | DIN 2527 |
| Threaded flange | Type 12 | DIN 2558, DIN 2565 – DIN 2569 |
| Flat flange | Type 01 | DIN 2573, DIN 2576 |
| Lapped flange | Type 02 and Type 04 | DIN 2641, DIN 2642, DIN 2655, DIN 2656 |
| Without raised face | Form A |
| Raised face (Rz = 160 mechanical turned) | Form B1 |
| Raised race (Rz = 40 mechanical turned) | Form B1 |
| Raised face (Rz = 16 mechanical turned) | Form B2 |
| Tongue according to DIN2512 | Form C |
| Groove according to DIN 2512 | Form D |
| Male according to DIN 2513 | Form E |
| Female according to DIN 2513 | Form F |
| Female according to DIN 2514 | Form G |
| Male according to DIN 2514 | Form H |
Furthermore, for sanitary applications such as in the food and beverage and pharmaceutical industries, sanitary flanges according to DIN 11853-2 STC are utilized. The primary distinction between sanitary flanges according to DIN 11853-2 and DIN/EN flanges lies in the restricted dead-room and the interior polishing according to hygienic levels of H1 to H4. Usually the flange traders that hold the Standard DIN EN 1092-1 such as Hage Fittings, do not hold Sanitary flanges as the storage requirements are different. Sanitary flanges are more delicate and need to stay clean. Usually the O-Rings, according to DIn 11853, are made out of FPM or EPDM.
The design of the flange face includes two independent seals. The first seal is created by application of seal seating stress at the flange heel, but it is not straight forward to ensure the function of this seal.
Theoretically, the heel contact will be maintained for pressure values up to 1.8 times the flange rating at room temperature.
Theoretically, the flange also remains in contact along its outer circumference at the flange faces for all allowable load levels that it is designed for.
The main seal is the IX seal ring. The seal ring force is provided by the elastic stored energy in the stressed seal ring. Any heel leakage will give internal pressure acting on the seal ring inside intensifying the sealing action. This however requires the IX ring to be retained in the theoretical location in the ring groove which is difficult to ensure and verify during installation.
The design aims at preventing exposure to oxygen and other corrosive agents. Thus, this prevents corrosion of the flange faces, the stressed length of the bolts and the seal ring. This however depends on the outer dust rim to remain in satisfactory contact and that the inside fluid is not corrosive in case of leaking into the bolt circle void.
Several different waveguide flange types exist, such as CAR, CBR, OPC, PAR, PBJ, PBR, PDR, UAR, UBR, UDR, icp and UPX.
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