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Tuesday, August 05, 2008

asbestos

Asbestos is the name given to a group of naturally occurring minerals used in certain products, such as building materials and vehicle brakes, to resist heat and corrosion, highly fibrous minerals with separable, long, and thin fibers. Asbestos includes chrysotile, amosite, crocidolite, tremolite asbestos, anthophyllite asbestos, actinolite asbestos, and any of these materials that have been chemically treated and/or altered. Separated asbestos fibers are strong enough and flexible enough to be spun and woven. Asbestos fibers are heat resistant, making them useful for many industrial purposes. Because of their durability, asbestos fibers that get into lung tissue will remain for long periods of time.

Asbestos is a naturally occurring mineral found in the surface of the earth. It contains strong fibres that have excellent durability, fire resistance and insulating properties. Asbestos fibres are 50 to 200 times thinner than a human hair, can float in the air for a long time, can be invisible to the naked eye and can be breathed into the lungs.

In the past, asbestos was mined from the ground and manufactured into many different materials. Materials containing asbestos were very common in the Australian residential building industry between the 1940s and late 1980s before their production stopped.

Serpentine and Amphibole. The division between the two types of asbestos is based upon the crystalline structure. Serpentines have a sheet or layered structure where amphiboles have a chain-like structure. As the only member of the serpentine group, Chrysotile( A, B) is the most common type of asbestos found in buildings. Chrysotile makes up approximately 90%-95% of all asbestos contained in buildings in the United States.

In the amphibole group, there are five types of asbestos. As an acronym for the Asbestos Mines of South Africa, Amosite is the second most prevalent type of asbestos found in building materials. Amosite is also known as "brown asbestos." Next, there is Crocidolite or "blue asbestos," which is an asbestos found in specialized high temperature applications. The other three types (Anthophyllite, Tremolite, and Actinolite) are rare and found mainly as contaminants in other minerals. Asbestos deposits can be found throughout the world and are still mined in Australia, Canada, South Africa, and the former Soviet Union.

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Posted by Pr1nc3s d4rkn3ss at 19:49:00 0 comments
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