Everything You Need to Know About Different Types of Flange Faces

What is Mean by Flange Faces?

Flanges are typically used to connect pipes and tubes. The flange face is the end of the flange that faces the other component in the connection. There are several types of flange faces, which are determined by the shape of the mating surface.

The most common type of flange face is the flat face. This type has a surface that is perpendicular to the pipe or tube. It is used when a tight seal is needed, such as in high-pressure or vacuum applications.

Another common type of flange face is the raised face. This type has a surface that is raised above the pipe or tube by a specified amount. It is used when a gap must be left between the components to allow for thermal expansion or when special sealing compounds are needed.

Types of Flange Faces

There are many different types of flange faces, each with its own advantages and disadvantages. Some of the most common types of flange faces are:

  1. Raised Face (Known as RF) Flange
  2. Flat Face (Known as FF) Flange
  3. Ring-Type Joint (Known as RTJ) Flange
  4. Tongue-and-Groove (Known as T&G) Flange
  5. Male-and-Female (Known as M&F) Flange- Small/ Large
  6. Lapped Joint

There are main six types of flange faces: flat, raised, tongue, groove, male and female. The type of flange face is determined by the shape of the mating surface on the adjoining pipe or fitting.

Each type of flange face has its own advantages and disadvantages.

What is Raised Face Flange (RF Flange)?

Raised Face Flanges are a type of flange that is designed to provide a smooth surface for sealing against the flange face of another pipe or component. You can find the height & diameters for RF Flange in ASME B16.5.

Raised Face Flanges have a raised (or protruding) edge around the circumference of the flange hole. This raised edge creates a seal between the mating surfaces of two flanges.

The raised face also helps to distribute stress evenly across the gasket, which improves the seal and reduces the chance of gasket failure. The flange face finish for Raised Face Flange is 3 µm Ra to 6 µm Ra as per ASME B16.5.

Raised Face (RF) Flange

A raised face flange is a type of flange that has a protrusion on the mating surface. This protrusion acts as a stop to ensure that the two parts are fully mated before any bolts are tightened. Raised face flanges are often used in high-pressure applications, as they help to prevent leaks.

What is Flat Face (FF) Flange?

Flat Face (FF) flanges are a type of flange where the face of the flange is flat. This type of flange is often used when connecting to a pipe or fitting with a raised face. FF Flanges must not be bolted to RF flanges.

Raised face flanges have a protrusion on the mating surface that helps to ensure a tight seal. Flat face flanges do not have this protrusion and can be more difficult to seal properly.

Flat Face (FF) Flange

This type of flange is often used in conjunction with other types of flanges, such as raised face flanges or ring joints.

What is RTJ (Ring-type Joint) FLange?

Ring-type Joint (RTJ) flanges are designed to connect pipes and valves in a manner that allows the flow of fluid through the interconnected piping system to continue uninterrupted.

RTJ Flange are used for high pressure applications (usually Class 600 & above rating) and/ or for high temperature application more than 427°C (800°F). 

The RTJ flange is a specialized type of flange that features grooves cut on their face, which fit into mating gasket. When two RTJ Flanges are bolted, gasket get compressed between the flanges in the groove & provide strong seal between two metals. This design provides a positive seal between the two components, preventing fluid leakage.

Ring type joint flange (RTJ) is a type of flange that is commonly used in piping and tubing systems. It is a type of threaded flange in which the mating threads are on the inside diameter of the flanges. This type of flange is often used in high-pressure or high-temperature applications.

What is Tongue-and-Groove (T & G) Flange?

Tongue-and-Groove flanges are a type of flange that required their face to be matched for effective sealing.

The flanges have a tongue on one flange face and a groove on the other flange face. This matching depression allows them to be connected securely and prevents leaks.

Tongue-and-groove flanges are self-aligning flanges. These flanges are available large size & small size.

What is Male-and-Female Flange?

Male-Female flange also must be having matching face to each other. A male flange has an extended area on its face, while a female flange has a depression in the middle to match male flange face.

This difference allows the two objects to be attached securely. If you try to attach a male flange to a female flange, or vice versa, it will not be very secure and may come loose over time.

The depth of depression in female flange face is 3/16 inches & height of male flange face is 1/4 inches. Two types of Male & Female Flanges are in use:

  1. Small Male & Female Flange.
  2. Large Male & Female Flange.

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