Magnesia pipe insulation is made from magnesia alba or magnesium carbonate which is an inroganic, inert product that was for many years used in medicine (milk of magnesia) and in other various manufacturing. In 1885 Hiram M Hanmore, a pipe coverer, began to mix magnesia with other pipe covering materials. In about the same time manufacturers of magnesia for medical purposes also began to discover the insulation capacity of the fine, white magnesia powder. Experiments soon were under way mixing magnesia with many materials in an effort to find the best insulator. Asbestos fibers was one of those materials and it acted as a binder to give strength and cohesion to the magnesia sludge which then could be cast or molded into standard shapes and dried. The optimum mix became 85 percent magnesia and 15 percent asbestos fibers. The principle type of asbestos fiber was chrysotile though amosite and crocidolite were also used. 85 percent magnesia pipe removed today after nearly a half a century or more is in just as perfect condition as when it was originally installed. Johns-Manville Corporation was founded in 1858 as the H. W. Johns Manufacturing Company of New York, N. Y. and was based on the principle uses of asbestos as fire resistant roofing material. In 1886 the inception of the Manville Covering Company of Milwaukee, Wisconsin was founded on the principle uses of asbestos as a heat insulating material. In 1901 H. W. Johns Manufacturing Company and Manville Pipe Covering Company merged to form H. W. Johns-Manville Company of New York, N. Y. The company was reincorporated as Johns-Manville Corporation in 1926. Between 1900 and the mid 1980s, asbestos was used in over 3,000 different products. During the 20th century, more than 30 million tons of asbestos were used in industrial facilities, homes, schools, shipyards, steel mills, power plants and commercial buildings in the United States. Asbestos is term used to describe six naturally occurring minerals with similar properties. In the simplest of terms, asbestos is a rock mined from the ground. Asbestos has several key physical properties, including its durability and resistance to heat and combustion. It is also fibrous in nature, which allows it to be spun and woven into cloth. Most chemicals do not affects asbestos, and it is also does not conduct electricity well. Asbestos is an extremely fibrous mineral and mining, milling, processing, or use of asbestos and its products create many small fibers. Because of their thin shape and small size, the asbestos fibers easily pass through the body's natural defenses designed to trap debris within the respiratory systems before reaching the lungs. Once inside the lungs, the asbestos fibers slice into the sensitive tissue causing irritation and scarring. Because asbestos fibers are so durable, the body is not able to break them down to remove them. Once in place, the fibers continue to generate scar tissue, progressively damaging the lungs; extensive scarring can lead to the development of asbestosis. Asbestos may also cause the development of mesothelioma or lung cancer. Under the authority of the Clean Air Act, the US EPA banned the use of most spray-applied surfacing used for fireproofing, insulation and decorative purposes and thermal system insulation for wet-applied and preformed asbestos pipe insulation and preformed asbestos block insulation on boiler and hot water tanks. For more information about asbestos and asbestos-related disease, go to http://www.mesotheliomacenter.org/resources/questions.php .
Properly insulated buildings reduce energy consumption by keeping heat in during the winter and out in the summer. Vats, tanks, vessels, boilers, steam and hot-water pipes, and refrigerated storage rooms also are insulated to prevent the wasteful loss of heat or cold and to prevent burns. Insulation also helps to reduce the noise that passes through walls and ceilings. Insulation workers install the materials used to insulate buildings and mechanical equipment. In making major renovations to old buildings or when putting new insulation around pipes and industrial machinery, insulation workers often must first remove the old insulation. In the past, asbestos—now known to cause cancer in humans—was used extensively in walls and ceilings and to cover pipes, boilers, and various industrial equipment. Because of this danger, U.S. Environmental Protection Agency regulations require that asbestos be removed before a building undergoes major renovations or is demolished. When asbestos is present, specially trained workers must remove it before insulation workers can install the new insulating materials. This is clipped from the 1930(?) silent film, The Story of Asbestos, produced by the US Bureau of Mines with the assistance of the Johns-Manville Company. The entire film is available from the US National Archive.
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ASBESTOS PIPE INSULATIONby asbestosottawa4,816 views
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