Types of Flange Facings

 

In our previous blog, we talked about the most common flange types used in the industry. Today, we would like to discuss on another important aspect of a flange – flange face. Understanding flange faces plays a crucial role to ensure that the right fit, right gasket and safety can be applied.

Flange face is the surface where contact between two flanges occur. A sealing component is generally introduced between the mating surface, such as metal or gasket. Below is a compilation of flange facing types that are commonly recognized in the market.

1.     FLAT FACE (FF)

Flat Face

As its names suggest, flat face flange has a flat face. This means that the gasket seat is on the same plane as bolting circle face. Flat face allows full contact across the whole face of the two mating flanges and uses full face gasket. Flat Face flange is used for equipment made from cast iron or other brittle materials hence is only applicable for low temperature and low-pressure applications. It is important to only mate flat face flange with flat face flange and not a raised face.

2.      RAISED FACE (RF)

Raised Face

Most widely used flange. Raised face flange has a small raised ring area around the bore where the gasket will be seated. Raised face flange can concentrate more pressure on a smaller gasket area and increases the seal and flange’s joint pressure containment capability. Raised face is typically used for equipment made from forged steel.

The height of the raised face depends on the flange’s pressure class rating. Pressure class 150 and 300 will have the height of raised face approximately 1.6mm (1/16 inch) while pressure class 400, 600, 900, 1500 and 2500 will have the height raised to approximately 6.4mm (1/4 inch).

3.     RING TYPE JOINT FACE (RTJ)

RTJ Flange

Ring type joint (RTJ) flange has an embedded circular grove on its raised face where gasket will seat. When two RTJ flanges are bolted and tightened together, the gasket inside the flange groove will be compressed and will form a tight metal to metal seal. Other benefit of RTJ flange is that the raised face protects the gasket from over compression. RTJ flange has a good pressure and temperature resistance and used for highly demanding applications.

RTJ uses a metallic sealing ring gasket that is suitable for high pressure and high temperature. The gasket comes in either oval or octagonal cross-sectional area. The latter has a better sealing property than the former but only applicable for latest flange design.

4.     TONGUE & GROOVE (T&G)

Tongue and Groove Flange

Tongue and groove (T&G) flange consist of two parts: tongue and groove. The tongue has a raised surface while the groove has a matching depression (groove) machined to its face. Both parts need to be matched to seal connection. Tongue and groove can self-align and has a good sealing property.

5.     MALE & FEMALE FACE (M&F)

Male and Female Flange

Male and Female face (M&F) has similar design with T&G except that its raised surface and groove’s ID extend into the bore hole. The male face is commonly mistaken as a raised face due to their similarities. The typical depth of the female groove is 3/16 inch while the typical height of the male raised face is ¼ inch.

Both tongue and groove and male and female have good sealing and accurate gasket compression. Their downside is their high cost due to lack of commercial availability.

FINAL WORD

If you are looking for any flanges, you may want to contact us at (65) 6298 3211 or enquiry@wahjooseng.com. Wah Joo Seng can assemble, deliver and supply our hose assemblies with flanges!  Check out our flange collections here!

REFERENCES, IMAGE CREDITS & SOURCE:

https://hardhatengineer.com/

http://www.wermac.org/flanges/flanges_welding-neck_socket-weld_lap-joint_screwed_blind.html

https://www.eng-tips.com/viewthread.cfm?qid=191786

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Flanges Like No Other

Flanges are used in many industries as a quick and economical joint for easy access, cleaning or modification for their equipment or lines. PVC, Carbon Steel, Cast Iron and Stainless Steel are commonly used materials in modern pipe infrastructure. However, the demand for better material has been increasing since the 1930s to fulfil the call for flanges with high level of corrosion resistance and functionality.

In order to address specific concerns especially for applications such as;

  • Chlor-Alkali
  • Bleaches
  • Solvents
  • Acid
  • Caustic

Wah Joo Seng is pleased to present our latest revolutionary flange that performs like no other – Durcor® flanges. These made in U.S.A flanges are proven to be the strongest, lightest and most chemically resistant. This flange combines the benefits of PVC, PTFE and steel. It gives you maximum protection while helping you to save more in the long run.

Durcor® Composite Flange
Durcor® flange is by far the strongest, lightest and most chemically resistant flange.

Lightweight

Durcor® is as light as plastic
You don’t have to break a sweat while carrying Durcor® products.

A special composite compound is at the core of Durcor® flanges, making them featherlight that aids in easy transportation and installation. Durcor® flange weighs similarly to PVC flange and just a fourth of the weight of stainless steel or carbon steel flanges.

Durcor® is relatively lighter when compared to other flanges
Flanges Weight Comparison Chart

 

Chemical Resistant

Durcor®’s backbone material, vinyl ester resin, can withstand aggressive chemicals and hostile atmospheres such as acid sprays, bleach, salt water and chlorides. Durcor®’s chemical resistance outperforms stainless and ductile iron flanges in both corrosive and non-corrosive environment.

Durcor® vs Carbon Steel Flange
16 hr exposure to 3:1 HCL/HNO3 bottom flange submerged
Durcor® chemical resistance test result
Result after 16 hours

Strength

Durcor® has tensile and compressive strength that is comparable to steel; followed by an outstanding impact resistance, Durcor® flange is claimed to be virtually indestructible. Its reinforcing fibers are long and interlocked which allows a systematic load distribution throughout the entire matrix when it is pressurized. Durcor® flange is 8 times stronger than PVC flange and just a slightly less than stainless steel or carbon steel. Furthermore, Durcor® flanges are ANSI B16.5 classified and available in Class 150lbs or Class 300lbs ratings.

Durcor® Tensile Strength Comparison
Tensile Strength Comparison

Other Benefits

Made is USA

Durcor® is made by following US standard
Durcor® Flange is Made in USA

Durcor® flanges are made according to U.S. strict manufacturing standard, using top quality raw materials.

Wide Temperature Range

Durcor® flange has a working temperature range of -60oF to 300oF (-50 oC to 150 oC). Making it suitable for a wide range of application.

Cost Reduction

Though Durcor® is higher in capital costs, their cost-efficiency benefits outweigh the cost in the long run thanks to their unique features.  Benefits of using Durcor® flanges include eliminating the need to install additional support, no painting required, zero corrosion rate, reduce the costs of maintenance, transportation, installation and prolonging service life.

Durcor® Total Cost Comparison
Total Cost Comparison of Durcor® vs other Flanges

Durcor®’s flange type

Our Durcor® Lap Joint flanges are available in Class 150lbs or Class300lbs. Lap Joint flange allows for quick bolthole alignment of the mating flange during installation without taking the extra precautions required during prefabrication of a welded flange.

If you’d like to learn more about different types of flanges, check our blog here.

If you are interested in Durcor® flanges and or pipes, call us at (65) 6298 3211 or drop us an email at kingflex@wahjooseng.com.

Looking for other things? Check out our website here.

 

Types of Flanges

Flange connection is one of the most commonly used joining method in the industry to connect pipes, valves, pumps, hoses and other equipment. It is often chosen because it is simple and convenient to use. Flange connections provide easy access for cleaning, inspection or modification. Connection or joint is made when two flange faces are aligned, brought together and tightened with bolts and nuts. Below is the detailed breakdown of a flange connection.

Flanges diagram

Based on the diagram above, flange connection can be broken down simply into flange faces, gasket and bolts & nuts.

Choice of flanges is largely dependable on;

  • Types/Standards ASME B16.5 and/or B16.47 etc.
  • Contact Surfaces (Raised Face, Flat Face, Ring Type Joint and etc)
  • Pressure Ratings (150lbs, 300lbs, 400lbs, 600lbs, 1500lbs and 2500lbs)
  • Design Temperature
  • Materials (Forged steel, Stainless steel, PVC, Special Materials)
  • Sizes and Wall Thickness (Schedule)

TYPES OF COMMONLY USED FLANGES

Lap Joint Flange

Lap Joint Flanges

Lap joint flange consists of 2 main parts: stub end and loose flange. The stub end will be welded to the pipe/fitting while loose flange will slip over the pipe and roam freely. Lap joint flange provides great flexibility for the assembly as it has the freedom to swivel and It is easy to line up.

Lap joint flange is suitable for application that requires frequent dismantling and lower pressure.

Weld Neck Flange

Weld Neck Flanges

Weld neck flange is characterized with a long-tapered neck/hub which then strongly welded with pipe. The neck/hub grows wider from the welded end to the flange face. Because the bore of both the pipe and hub matches, creating a seamless flow path, erosions and turbulences can be greatly reduced. Weld neck flange is a great fit for higher pressure and higher temperature application.

The downside of weld neck flange is that it is bulkier and relatively higher in cost.

Socket Weld Flange

Socket Welded Flanges

Socket weld flange has a female socket inside its bore hole as the resting place for the inserted hose. Socket weld flange is suitable for low pressure and low temperature application. A gap of 1/16” (shown by x) between the hose end and the socket needs to be maintained to reduce residual stress that could occur during solidification of the weld metal. The flange and the hose will then be welded together.

Slip-On Flange

Slip On Flanges

Similar like socket weld flange, slip-on flange has a bore hole in which hose can slip-on. The only different is that slip-on flange does not have a female socket for the hose to rest. Slip-on flange has lower strength when compared to weld neck flange.

Blind Flange

Blind Flanges

Blind flange entirely blank off the hose end to terminate the fluid flow and isolate the piping system. Blind flange is applicable for high pressure.

Threaded Flange

Threaded Flanges

Threaded flange uses thread to secure the connection between the hose and the flange. It is fast, simple and easy to assemble or disassemble.

However, threaded flange is only applicable for low pressure and the threaded pipe needs to be relatively thicker to form the thread to screw on.

In Summary

Types of Flanges Characteristics
Lap Joint Flange ·         Consists of stub end and lap joint flange

·         Flange can roam and rotate freely

·         Applicable for low pressure

·         Easy to install and dismantle

·         Flange does not touch the fluid, hence can be salvaged

Weld Neck Flange ·         Long tapered neck/hub as a strong support

·         Suitable for higher pressure and temperature

·         Bulky and relatively costlier

Socket Welded Flange ·         Slip in bore hole in the centre

·         Bore hole has a female socket in which a pipe is fitted

·         Applicable for low pressure and temperature application

Slip-On Flange ·         Slip in bore hole in the centre

·         Applicable for low pressure

Blind Flange ·         Blank off end to terminate flow

·         Applicable for high pressure.

Threaded Flange ·         Threading inside of flange bore hole

·         Hose has thick wall thickness

·         Easy to connect/disconnect

·         Applicable for low pressure

Final Word

If you are looking for any of these flanges, you may like to contact us at (65) 6298 3211 or enquiry@wahjooseng.com. Wah Joo Seng can assemble, deliver and supply our hose assemblies with flanges!  Check out our flange collections here!

References:

Hardhat Engineer.

Wermarc.

Wikimedia.