What is the difference face of flange?

To answer this question, you have to learn about different type of flange faces. Here in the image, you can see the different types of flange faces.

• Flat Face (FF)
• Raised Face (RF)
• Lap Joint
• Ring Joint (RTJ)
• Male and Female types
• And Tongue and groove (T&G)

Now out of these types, flat face, raised face, and RTJ face is regularly used in piping. Let’s learn about them. Check the image; you can see these three types of face.

Types of flange face

Flat Face

As the name suggests, flat face flange has a flat face. Flat face flanges are used when the counter flange has a flat face. This condition occurs mainly on connection to Cast Iron equipment, valves, and specialties. Full face non-metallic gasket is used when a flat face flange is used. This type of flange not used in high pressure and temperature application.

EN1092 Q235 FF plate flanges

Raised Face

Raised face flange has a small portion around the bore that is raised from the face. The gasket seat on this raised face. The height of the raised face depends on the flange pressure-temperature rating that is known as a class of the flange. This type of flange is used in high pressure and temperature application.

ASME B16.5 class 600 ASTM A105 RF weld neck flange

RTJ Face

Ring joint type face flange has a specially designed grove in which metal gasket seat. This type of flange is used in very high pressure and temperature services.

ANSI B16.5 A105N RTJ weld neck flanges