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

During this time period, estimated domestic production declined 99.7 percent,
from 952.34 to 3 short tons and fiber consumption declined 99.8 percent, from
877.54 to 2.1 short tons (ICF l986a, ICF 1985, TSCA 1982).
In 1986, Durametallic Corporation, which accounted for two-third of the
total output for asbestos packings in 1985, ceased processing because of
costly insurance
premiums and the possibility of regulatory action
(ICF
1986a).
D. Substitutes
Asbestos-containing packings, the large majority of which are based on
various compositions and configurations of braided yarn, have dominated the
market until very recently.
A typical high performance braided asbestos
packing includes an alloy wire reinforcement, various lubricants, a zinc
powder corrosion inhibitor,
and a graphite powder lubricant coating on the
yarn itself (Union Carbide 1987). In addition, these packings may contain
various binders (e.g., elastomers or resins), fillers (e.g., mica, clay, or
asbestos) and dry lubricants (Monsanto 1987).
Asbestos fibers have been used to make the braided jackets for packings
because of the favorable qualities that asbestos imparts to products made from
it. Asbestos-containing packings are ideally suited for high temperature and
pressure, as well as corrosive environments. Braided asbestos packings show
good acid/fire resistance, low thermal conductivity, and molten metal
resistance. Asbestos also withstands fairly high pressures (up to 4500 psi at
room temperature)
and exhibits good tensile strength and abrasion resistance
(Klein 1987). Another property of asbestos packings that has made them a
standard in the packing industry is their good compressibility and recovery
(EPRI 1982).
The packing industry has been unable to find a single substitute for
asbestos that can reproduce its numerous qualities. Hence, manufacturers have
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