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Fibre Characteristics
Chrysotile
Chrysotile has soft, curly fibres
and is used in asbestos cement, vinyl floor tiles, roofing felt,
insulation materials, oven gloves. It is readily attacked by acid and
mixes well with water, unlike other types of asbestos.
Amosite
The fibres of
Amosite asbestos are rigid and straight which repel water and are
therefore a good sound and heat insulator. It can be found in pipe
insulation, insulating boards, sprayed asbestos, vessel and boiler
insulation.
Crocidolite
In terms of the
properties of the material, this is the best asbestos available. It has
straight, needle-like fibres and Amosite drainage properties. Its
tensile strength is greater than Chrysotile and it can also be spun.
Uses include rope, insulation, steelwork spray protection and is
occasionally found in asbestos cement boarding.
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Main Properties
Chemical
Breaks down in temperatures in excess of
600 degrees C but the fibres do not have melting points, giving the
material excellent fireproofing qualities. The material will only fuse
if the temperatures are in excess of 1000 degrees C. Chrysotile is
broken down by acids, while Amosite and Crocidolite are more resistant
Physical
Tensile strength only
bettered by carbon fibres. Very resilient and therefore used widely in
the friction industry, for example, brakes. Asbestos, therefore,
becomes an excellent mechanical reinforcement in cement, plastic and
glass fibre based products
Thermal
Individual fibres have poor
thermal conductivity and therefore make excellent thermal insulation to
pipework, vessels, boilers and other heating sources. Thermal
conductivity is not affected by weathering |
