Asbestos board
Description
A construction or insulating board made from Asbestos fibers mixed with consolidates, then molded under high pressure. An early asbestos-containing millboard, Crocidolite (blue), was made from 1896-1965. It contained Chrysotile (white) asbestos in concentrations of 37-97% in a matrix of Clay and Starch. Later boards, such as Amosite, contained 15-25% of the brown asbestos in calcium silicate. The boards were used for fire protection and can withstand temperatures up to about 540C (1000 F). The boards were advertised as inexpensive, fireproof alternatives to wood and were used extensively in mid-19th century structures. They are typically found in service ducts, firebreaks, infill panels, partitions, walls, sidings, flooring, roof underlays and ceilings (including ceiling tiles).
As the boards tend to be brittle and broken easily, the dangerous fibers can be released. Since 1980, when the use of asbestos has been banned, these boards are now made with asbestos substitutes such as Mineral wool or glass fibers.
Synonyms and Related Terms
fibrociment (Fr.); fibrocimento (Port.); cement asbestos board; asbestos cement; AC; fibro, fibrous cement
Brand names: Asbestos Air Cell; Transite; Crosicolite (blue); Amosite (brown)
Physical and Chemical Properties
- Density = 2.0 g/ml
Resources and Citations
- Oracle Solutions [website]
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 73
- Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
- Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
- Thomas C. Jester (ed.), Twentieth-Century Building Materials, McGraw-Hill Companies, Washington DC, 1995
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000