Hobbies And Interests
History
Around 2500 BC Finland, people were already using asbestos to reinforce clay utensils and pottery. The Greeks were weaving asbestos fibers into lamp wicks in the fifth century BC. Ancient Persian kings used to drape tablecloths woven from asbestos fibers over their banquet tables. At the end of the meal, the servants would throw the tablecloth into the fire to burn any spills on the cloth. Peter the Great of Russia created asbestos paper in the 17th century. In the late 19th century, asbestos began to appear in commercial products. Most manufacturers stopped using asbestos in the 1970s and 1980s because of its health hazards.
Types
Asbestos has low thermal conductivity levels, which means that it transmits low quantities of heat per unit thickness. However, various asbestos products have different levels of thermal conductivity. Asbestos cement, for example, has a thermal conductivity level of 2.07 watts per kelvin per meter (W/mK), which is almost comparable to ice or some types of marble. Loosely packed asbestos and asbestos mill board have thermal conductivity of 0.15 W/mK and 0.14 W/mK respectively, almost comparable to clay, dry sand, soil or high-density hardboard.
Uses
In modern times, people have manufactured at least 5,000 different products from asbestos. It appears as insulation in vehicles' brake shoes, valve packing materials and clutch facings. Buildings often use asbestos in fireproofing materials, pipe insulation, heating ducts, spray-applied insulation and sealants. Despite its usefulness as insulation material, the Environmental Protection Agency has banned people from creating new uses from asbestos due to its health risks.