Asbestos
Asbestos is a set of six natural minerals. The most common form of asbestos is white asbestos, which makes up 95% of the asbestos found in buildings. It occurs naturally in all parts of the world. It is fibrous, heat resistant and non flammable. These properties made it very attractive as a component in building materials and other products such as insulation and automobile brake pads. People have used asbestos throughout history. Ancient Egyptian people used asbestos. Asbestos is extremely dangerous for human health, as it can cause breathing and lung problems if people are around it for a long period of time.
Asbestos was linked to cancer in the early 1970s[1] and was replaced by other materials in most applications by 1980.
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[change] Types of asbestos
There are six types of asbestos:
- Chrysotile (white asbestos)
- Crocidolite (blue asbestos)
- Amosite (brown asbestos)
- Anthophyllite asbestos
- Tremolite asbestos
- Actinolite asbestos
[change] Substitutes
- Fiberglass - This is the most popular substitute. Fiberglass is physically similar to asbestos and its safety is also being questioned.
- Carbon fiber - Lighter weight than fiberglass or asbestos, but not heat resistant
- Wood fiber mixed with cement (in non-heat applications)
- Various polymer and plastic fibers
- Asbestos rope can be replaced with steel cable
- Vermiculite insulation is a common substitute, although vermiculite itself can be contaminated with asbestos
- Basalt fiber is a mineral fiber with properties similar to asbestos. It is suitable for high-heat applications.
- Mineral wool is a common substitute that is popular in Europe
- Silica aerogel is the best insulator available. It is non-fibrous and is not easily inhaled into the lungs.
[change] References
- ↑ Burke, Bill (6 May 2001) "Shipyards, a Crucible for Tragedy: Part 1: How the war created a monster" Virginian-Pilot Norfolk, Virginia (newspaper)
