RF
RF is an abbreviation of Raised Face, and designed for flanges.
The Raised Face type are the most applied flange type, and is easily to identify. It is referred to as a raised face because the gasket surfaces are raised above the bolting circle face. The height in Pressure Class up to 300 Lbs is approximately 1.6 mm, and in Pressure Class 400 up to 2500 Lbs the height is approximately 6.4 mm. Pressure rating of the flange determines the height of the raised face. 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.
RFC
RFC is an abbreviation of Released For Construction.
RFC means that the release for construction (after Approved For Construction) is given...start the project.
RTJ
RTJ is an abbreviation Ring Type Joint flanges.
Ring Type Joint flanges have grooves cut into their faces which steel ring gaskets. The flanges seal when tightened bolts compress the gasket between the flanges into the grooves, deforming (or coining) the gasket to make intimate contact inside the grooves, creating a metal to metal seal.
