Editing Flange (section)

== Types of flanges ==
Flanges come in various types, each designed to meet specific requirements based on factors such as pressure, temperature, and application. Some common types include:

# [[Weld neck flange|Weld Neck Flanges]]: Weld neck flanges feature a long tapered hub that provides reinforcement to the connection, making them suitable for high-pressure and high-temperature applications.
# Slip-On Flanges: Slip-on flanges have a slightly larger [[diameter]] than the [[Pipe (fluid conveyance)|pipe]] they connect to and are slipped over the pipe before welding. They are commonly used in low-pressure and non-critical applications.
# Socket Weld Flanges: Socket weld flanges have a recessed area (socket) into which the pipe end fits, allowing for fillet [[welding]]. They are suitable for small-bore piping systems and applications with moderate pressure and [[temperature]] requirements.
# Blind Flanges: Blind flanges are solid discs used to close the end of a piping system or [[Vessel (Twenty One Pilots album)|vessel]]. They are often used for pressure testing or as a permanent seal when a pipe end needs to be closed off.

=== ASME standards (U.S.) ===
[[File:Flanschverbindung Gasleitung.jpg|thumb|right|Two ASME type flanges, bolted together on a gas pipeline]]

Pipe flanges that are made to standards called out by [[American Society of Mechanical Engineers|ASME]] B16.5 or ASME B16.47, and MSS SP-44. They are typically made from forged materials and have machined surfaces. ASME B16.5 refers to [[nominal pipe size]]s (NPS) from {{frac|1|2}}" to 24". B16.47 covers NPSs from 26" to 60". Each specification further delineates flanges into [[pressure]] classes: 150, 300, 400, 600, 900, 1500 and 2500 for B16.5, and B16.47 delineates its flanges into pressure classes 75, 150, 300, 400, 600, 900. However these classes do not correspond to maximum pressures in [[Pounds per square inch|psi]]. Instead, the maximum pressure depends on the material of the flange and the temperature. For example, the maximum pressure for a Class 150 flange is 285 psi, and for a Class 300 flange it is 740 psi (both are for ASTM a105 carbon steel and temperatures below 100&nbsp;°F).

The [[gasket]] type and [[Screw|bolt]] 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|stud bolts]] 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.

=== European dimensions (EN / DIN) Hygienic Flange STC DIN11853-2 ===
Most countries in Europe mainly install flanges according to standard DIN EN 1092-1 (forged stainless or steel flanges). Similar to the ASME flange standard, the EN 1092-1 standard has the basic flange forms, such as weld neck flange, blind flange, lapped flange, threaded flange (thread ISO7-1 instead of NPT), weld on collar, pressed collars, and adapter flange such as flange coupling GD press fittings. The different forms of flanges within the EN 1092-1 (European Norm/Euronorm) is indicated within the flange name through the type. 
{| class="wikitable"
!Design
!According to EN type
!According to DIN 
|-
|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
|}
Similar to ASME flanges, EN1092-1 steel and stainless flanges, have several different versions of raised or none raised faces. According to the European form the seals are indicated by different form:

{| class="wikitable"
!Form: types of contact faces
!DIN EN 1092-1
|-
|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.

=== Other countries ===
Flanges in the rest of the world are manufactured according to the [[International Organization for Standardization|ISO]] standards for materials, pressure ratings, etc. to which local standards including [[Deutsches Institut für Normung|DIN]], [[British Standards|BS]], and others, have been aligned.