Pipe Flange Types and Kinds

Pipe Flanges
A pipe flange is disc, collar or ring that attaches to pipe with the purpose of providing increased support for strength, blocking off a pipeline or implementing the attachment of more items. Pipe flanges are usually welded or screwed to the pipe end and are connected with bolts. A gasket is inserted between the two mating flanges to provide a tighter seal. Pipe flanges are either custom with dimenions provided by the customer or they are manufactured according to published specifications. Several organizations and associations have published specifications that provide dimensional information as well as pressure specifications at different temperatures. Hyupshin Flange manufactures custom flanges and stocks 6 basic types of pipe flanges. Although, these are the 6 most common types of pipe flanges, Hyupshin Flange is a custom flange manufacturer as well and is able to create just about any type of flange necessary for your requirements. Please click on one of the following pictures for a more detailed description of the pipe flanges you are interested in. Each page also has a video that provides a better understanding of how the pipe flanges are connected to the pipe.

SLIP-ON PIPE FLANGES

Slip-on pipe flanges actually slip over the pipe. These pipe flanges are typically machined with an inside diameter of the pipe flange slightly larger than the outside diameter of the pipe. This allows the flange to slide over the pipe but to still have a somewhat snug fit. Slip-on pipe flanges are secured to the pipe with a fillet weld at the top and the bottom of the slip-on pipe flanges. These pipe flanges are also further catagorized as a ring or a hub. Ring pipe flanges and hub pipe flanges are both considered slip on pipe flanges because they both slip over the pipe. Slip on Pipe flanges with a hub have published specifications that range from 1/2″ thru 96″. Slip on pipe flanges that consist of a flat ring have published specificiations that range from 1/2″ thru 144″. Hyupshin Flange provides Slip-On pipe flanges in all material grades, specifications and sizes.

WELD NECK PIPE FLANGES

Weld neck pipe flanges attach to the pipe by welding the pipe to the neck of the pipe flange. The allows for the transfer of stress from the weld neck pipe flanges to the pipe itself. This also reduces high stress concentration at the base of the hub of the weld neck pipe flanges. Weld neck pipe flanges are often used for high pressure applications. The inside diameter of a weld neck pipe flange is machined to match the inside diameter of the pipe. Weld Neck Pipe flanges with a hub have published specifications that range from 1/2″ thru 96″. Hyupshin Flange provides Weld Neck pipe flanges in all material grades, specifications and sizes.

BLIND PIPE FLANGES

Blind pipe flanges are pipe flanges used to seal the end of a piping system or pressure vessel openings to prevent flow. Blind pipe flanges are commonly used for pressure testing the flow of liquid or gas through a pipe or vessel. Blind pipe flanges also allow easy access to the pipe in the event that work must be done inside the line. Blind pipe flanges are often used for high pressure applications. Slip on Pipe flanges with a hub have published specifications that range from 1/2″ thru 96″. Hyupshin Flange provides Blind pipe flanges in all material grades, specifications and sizes.

LAP JOINT PIPE FLANGES

Lap Joint Pipe Flanges slide over the pipe and are most commonly used with Stub End Fittings. A pipe is typically welded to the Stub End and the Lap Joint pipe flange is free to rotate around the stub end. The benefit of this is that there will not be any issues with bolt hole alignment. Lap Joint pipe flanges are often used for applications that require frequent dismantling. Slip on Pipe flanges with a hub have published specifications that range from 1/2″ thru 24″. Sizes above 24″ are produced as lap joints to slip on dimensions. Hyupshin Flange provides Lap Joint pipe flanges in all material grades, specifications and sizes.

THREADED PIPE FLANGES

Threaded pipe flanges are similar to slip-on pipe flanges except the bore of threaded pipe flange has tapered threads. Threaded pipe flanges are used with pipes that have external threads. The benefit of these pipe flanges is that it can be attached without welding. Threaded pipe flanges are often used for small diameter, high pressure requirements. Slip on Pipe flanges with a hub have published specifications that range from 1/2″ thru 24″. Hyupshin Flange provides Slip-On pipe flanges in all material grades, specifications and sizes.

SOCKET-WELD PIPE FLANGES

Socket-weld pipe flanges are typically used on smaller sizes of high pressure pipes. These pipe flanges are attached by inserting the pipe into the socket end and applying fillet weld around the top. This allows for a smooth bore and better flow of the fluid or gas inside of the pipe. Slip on Pipe flanges with a hub have published specifications that range from 1/2″ thru 24″. Hyupshin Flange provides Socket Weld pipe flanges in all material grades, specifications and sizes.

Pipe flanges

There are many different flange standards to be found worldwide. To allow easy functionality and inter-changeability, these are designed to have standardised dimensions. Common world standards include ASA/ANSI (USA), PN/DIN (European),[1] BS10 (British/Australian),[2] and JIS/KS (Japanese/Korean).

In most cases these are not interchangeable (e.g. an ANSI flange will not mate against a JIS 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 ANSI 150 will not mate with an ANSI 300). 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 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 “welding neck”, “slip-on”, “boss”, “lap joint”, “socket weld”, “threaded“, and also “blind”.

ASME standards (U.S.)

ASME type flange on a gas pipeline

Pipe flanges that are made to standards called out by ASME B16.5 or ASME B16.47 are typically made from forged materials and have machined surfaces. B16.5 refers to nominal pipe sizes (NPS) from ½” 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; B16.47 delineates its flanges into pressure classes 75, 150, 300, 400, 600, 900.

The gasket type and 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.

Other countries

Flanges in other countries also are manufactured according to the standards for materials, pressure ratings, etc. Such standards include DIN, BS,[3] and/or ISO standards.

ANSI/ASME Flanges

Hyupshin Flanges provides ASME Code and Non Code Industrial flanges for the Petrochemical, Process, and Waterworks industries. ANSI, API, AWWA pipe flanges in carbon, stainless, alloys and chrome steel. Weld Neck, Slip on, Blind, Threaded, Socket Weld, Lap Joint, Orifice Flanges, Ring, and custom flanges in sizes 1/2″ to 80″.  Pressure classes – 75, 125, 150, 175, 250, 300, 350, 400, 600, 900, 1500, 2500, 5K, 10K, 15K, 20K.  High Yield – Low Temp.

Pipe flanges

Pipe flanges

There are many different flange standards to be found worldwide. To allow easy functionality and inter-changeability, these are designed to have standardised dimensions. Common world standards include ASA/ANSI (USA), PN/DIN (European), BS10 (British/Australian), and JIS/KS (Japanese/Korean).

In most cases these are not interchangeable (e.g. an ANSI flange will not mate against a JIS 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 ANSI 150 will not mate with an ANSI 300). 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 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 “welding neck”, “slip-on”, “boss”, “lap joint”, “socket weld”, “threaded”, and also “blind”.

ASME standards (U.S.)

ASME type flange on a gas pipeline

Pipe flanges that are made to standards called out by ASME B16.5 or ASME B16.47 are typically made from forged materials and have machined surfaces. B16.5 refers to nominal pipe sizes (NPS) from ½” 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; B16.47 delineates its flanges into pressure classes 75, 150, 300, 400, 600, 900.

The gasket type and 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.

Other countries

Flanges in other countries also are manufactured according to the standards for materials, pressure ratings, etc. Such standards include DIN, BS, and/or ISO standards.