When it comes to choosing all parts and components in plumbing and piping systems, making the right choice for each part is important. Unfortunately, even the best-designed system can have a weak point if the incorrect part is installed and it fails.
For most flanges, the two options to consider for sealing are the full face gasket and the ring-type gasket. The biggest factor in choosing between the two is the actual flange face.
Flange Issues
The raised face flange is easy to see and is used in many different applications from processing plants to refinery systems. This is a flange with an inner edge that is raised above the face area, which allows the gasket to rise up and above the bolting circle surface for a smaller area of contact. The result of this is more pressure applied to the gasket for enhanced seal.
The flat faced flange has a smooth and even bolting circle face. This means that the full face gasket has holes that match up with the bolting circle, and the entire face of the flange is covered.
It is important to note that it is not possible to connect a raised face and a flat faced flange, regardless of the type of gasket in use.
Benefits of the Full Face Gasket
The wider coverage offered with the full face option in a gasket provides more surface coverage. This style of gasket can be used on both a raised and a flat face flange and offers greater protection from dirt or debris entering into the flange once the gasket is in place and it is tightened.
When choosing a full face gasket, it is essential to know the outside diameter, the inside diameter as well as the bolt circle diameter and the number of bolt holes. In some cases, and if bolt holes are irregularly positioned around the flange, custom gaskets may be required.
