The flange face is the surface area that hosts the gasket. ... Flanges with different faces require different gaskets and shall never be mated to prevent leakage of the joint. RF and FF flanges may have different types of “finish” (i.e. roughness on top the surface): smooth, stock and serrated.20 sept 2017
What is a flat faced flange?
The Flat Face flange has a gasket surface in the same plane as the bolting circle face. Applications using flat face flanges are frequently those in which the mating flange or flanged fitting is made from a casting. Flat face flanges are never to be bolted to a raised face flange.3 jul 2014
Are all ANSI flanges raised face?
Raised face flanges are available in most types of flanges. ... All of the ANSI pressure classes are available with raised face flanges. Gaskets for a raised face flange can be whatever is suited for the process. They can be spiral wound gaskets or non metallic gaskets.16 may 2016
Can RF flange connect to FF flange?
Some codes such as ASME B31. 1 prohibit connecting FF flanges to RF flanges. Although it does not directly address FF cast brass flanges used with raised face flanges, the intent of the specification is to prevent the cracking of the more brittle flange.
What is RF in 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.3 jul 2014
What is RF and FF?
Introduction to Flange Faces. Flanges are an integral part of the Piping industry. These Flanges are used to form a link between two different Pipes. Flat (FF), elevated (RF), ring joint (RTJ), lap joint (M&F), tongue, and groove (T&G) are the 6 styles of flange faces needed.27 feb 2020
What are the different types of flanges?
The key types of flanges are the welding neck, long welding neck, slip-on, socket weld, lap joint, threaded and blind flanges. In addition to these standard flanges, some special ones exist, called Weldoflange/Nipoflange and Elboflange, swivel flange, expander/reducer flange, and orifice flanges.20 sept 2017
How many different flanges are there?
There are four types of industry standards covering different flange types; ANSI Flange, also called ASME B16. 5 Flange. ASME Flange, also called ASME B16.
What is difference between RF and RTJ flanges?
Answer: RF means "Raised Face." RTJ means "Ring Type Joint." RF flanges seal with a flat gasket, formerly made of asbestos but now made of more environmentally friendly material, designed for installation between the raised faces of two mating flanges (both with raised faces).
Can you connect a RF flange to a FF flange?
RF flanges are commonly used on forged steel or forged stainless steel flanges. An RF flange uses a gasket called a ring gasket. ... FF flanges are made specifically to mate with other FF flanges. These flanges are often made from cast instead of forged metal.
Why do flanges have raised face?
Raised Face and Flat Face The raised face is intended to decrease the surface area of the seal, thus concentrating the surface pressure applied when mating the flange. The result is a stronger seal. The raised face has a machined serrated finish that will bite into the gasket whenever pressure is applied.6 may 2020
Can you use a ring gasket on a flat face flange?
When it comes to sealing raised or flat face flanges, two types of gaskets can be used: ring and full-face gaskets. Each type is best suited for specific flange designs, so knowing the difference is important for choosing the type that will best service your application.