flat face
- October 24, 2017
When sealing raised or flat face flanges, there are two choices of gasket shape: ring-type or full-face. Each has its own advantages, so you should know which will best suit your application before ordering and installing. First, let's discuss the types of flanges in which gaskets are installed.
Flange Faces
Different types of flange faces are used as the contact surface to seat the sealing gasket materials. ASME B16.5 and B16.47 define various types of flange facings, including the raised face, the large male and female facings which have identical dimensions to provide a relatively large contact area.
Raised Face (RF) Flanges
The Raised Face flange is the most common type used in process plant applications, and is easily to identify. It is referred to as a raised face because the gasket surfaces are raised above the bolting circle face. This face type allows the use of a wide combination of gasket designs, including flat ring sheet types and metallic composites such as spiral wound and double jacketed types.
The purpose of a RF flange is to concentrate more pressure on a smaller gasket area and thereby increase the pressure containment capability of the joint. Diameter and height are in ASME B16.5 defined, by pressure class and diameter. Pressure rating of the flange determines the height of the raised face.
