Gaskets are materials used to seal one compartment of a device ...

about twenty times more expensive than asbestos, by weight, but because they
are less dense and stronger, less is needed for reinforcement purposes. At
higher temperatures, the fibers physically degrade and thus are not good
replacements for asbestos products for high temperature applications.
Aramid packings are usually 20 percent aramid fiber, by weight, and 60 to
65 percent filler, while the remaining 20 to 25 percent is binder to keep the
fibers in a matrix. Typical applications for valves and pumps require a very
strong packing material that will withstand moderate
temperatures and
pressures without deteriorating.
Raymark Corporation, in Stratford, CT, was the only asbestos packing
manufacturer to cite aramid packings as a substitute for asbestos products.
They can be used for general service in most plants (A.W. Chesterton 1983).
Aramid-based products are likely to be 1.5 to 3 times as expensive as the
asbestos products they replace, therefore aramid packings cost between $45.30
and $90.60 per pound. The price increase is due to production and material
cost increases
(ICF l986a).
There are no performance disadvantages due to the dilution of the aramid
fiber with mineral
fillers and this helps to reduce the price of packings.
The service life is estimated to be the same as the life of the asbestos
product. Industry estimates indicate that aramid products will capture 20
percent of the total packings market. The average price for an aramid-based
packing is estimated to be $67.95 per pound (ICF l986a, Palmetto Packing
1986).
2. Fibrous Glass Mixtures
Fibrous glass is generally coated with a binder such as neoprene, TFE,
or graphite in the manufacturing process to make packings. Glass fibers are
relatively easy to process into packing materials and are used extensively in
packing materials.
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