While there are many new elastomeric sealing materials, it’s often prudent to follow the mantra, “What comes out of the joint goes back into the joint.” Especially in older processing and heating equipment that is often a fiber gasket. Many different materials can be used to provide the fibers, so the properties and applications of these gaskets vary enormously.
Back to Asbestos Gaskets
In 1899 an Austrian called Richard Klinger discovered a way of making effective soft gaskets by compressing asbestos fibers into sheet form. These sealed under low loads and resisted steam, oil, water and high temperatures and pressures. That made them ideal for use in boilers, heat exchangers and heating and hot water systems as well as oil refining and other process industries.
By the 1980’s the health hazards of asbestos were well-known and gasket manufacturers were substituting other materials with similar properties. Sticking with fibrous material in a binder meant they could use the existing manufacturing processes, one reason why fiber gaskets remain commonplace today.
Modern Fiber Gaskets
The main types of fiber gasket material are:
- Cellulose with rubber
- Cellulose with insulating fiber
- Cellulose with synthetic fiber
- Cellulose with vulcanized fiber
- Vegetable fiber (Detroiter)
These are all available in a range of sheet thicknesses and die-cut readily. They are considered “soft” gaskets, meaning they are suitable for applications with relatively low clamping forces, such as Class 150 and 300 flanges.
Fiber Gasket Properties
Gasket properties are determined by both fiber and binder material. For example:
- Vegetable fiber (Detroiter) gaskets – upper temperature limit of around 250°F (121°C), good resistance to oil, gasoline, water and steam. Generally inexpensive.
- Cellulose fiber with rubber – upper temperature limit around 350°F (177°C), good resistance to oil, gasoline, water and steam.
- Aramid fiber in NBR binder – upper limit on temperature can be up to 825°F (440°C), suitable for a wide range of industrial applications.
Fiber Gasket Identification
If you’ve removed a fiber gasket and aren’t sure what type it is, bring it in. Our materials experts should be able to help.