Transite
Encyclopedia
Transite originated as trade name that The Johns-Manville Corporation
created for a line of asbestos-cement products, including boards and pipes. In time it became something of a generic term for other companies' similar asbestos-cement products, and later an even more generic term for a hard, fireproof composite material
, fiber cement boards, typically using in wall construction.
The use of asbestos
to manufacture transite was phased out in the 1980s. Previously transite was made of cement
, with varying amounts (12-50%) of asbestos
fiber to provide tensile strength (similar to the steel in reinforced concrete
), and other materials. It was frequently used for such purposes as furnace flues, shingles, siding, and wallboard for areas where fire retardancy is particularly important. It was also used in walk-in coolers made in large supermarkets in the 1960s, 1970s and even the 1980s. Other uses included roof drain piping, water piping, sanitary sewer drain piping, and HVAC ducts. Because cutting, breaking, and machining asbestos-containing transite releases carcinogen
ic asbestos fibers into the air, its use has fallen out of favor.
The transite that is produced today is made without asbestos.
Transite HT, and Transite 1000 are currently available fiber cement boards that contain no asbestos. Instead they contain crystalline silica which has been classified by The International Agency for Research on Cancer (IARC) as being carcinogenic to humans (Class 1). Crystalline silica is also known to cause Silicosis
, a non-cancerous lung disease.
Demolition of older buildings containing transite materials, particularly siding made from transite requires special precautions and disposal techniques to protect workers and the public.
Johns-Manville
Johns Manville is an American corporation based in Denver, Colorado that manufactures insulation, roofing materials, and engineered products. The stock was included in the Dow Jones Industrial Average from January 29, 1930 to August 27, 1982 when it was replaced by American Express. Berkshire...
created for a line of asbestos-cement products, including boards and pipes. In time it became something of a generic term for other companies' similar asbestos-cement products, and later an even more generic term for a hard, fireproof composite material
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
, fiber cement boards, typically using in wall construction.
The use of asbestos
Asbestos
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...
to manufacture transite was phased out in the 1980s. Previously transite was made of cement
Portland cement
Portland cement is the most common type of cement in general use around the world because it is a basic ingredient of concrete, mortar, stucco and most non-specialty grout...
, with varying amounts (12-50%) of asbestos
Asbestos
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...
fiber to provide tensile strength (similar to the steel in reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...
), and other materials. It was frequently used for such purposes as furnace flues, shingles, siding, and wallboard for areas where fire retardancy is particularly important. It was also used in walk-in coolers made in large supermarkets in the 1960s, 1970s and even the 1980s. Other uses included roof drain piping, water piping, sanitary sewer drain piping, and HVAC ducts. Because cutting, breaking, and machining asbestos-containing transite releases carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
ic asbestos fibers into the air, its use has fallen out of favor.
The transite that is produced today is made without asbestos.
Transite HT, and Transite 1000 are currently available fiber cement boards that contain no asbestos. Instead they contain crystalline silica which has been classified by The International Agency for Research on Cancer (IARC) as being carcinogenic to humans (Class 1). Crystalline silica is also known to cause Silicosis
Silicosis
Silicosis, also known as Potter's rot, is a form of occupational lung disease caused by inhalation of crystalline silica dust, and is marked by inflammation and scarring in forms of nodular lesions in the upper lobes of the lungs...
, a non-cancerous lung disease.
Demolition of older buildings containing transite materials, particularly siding made from transite requires special precautions and disposal techniques to protect workers and the public.