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Definition & Chemical Composition of Asbestos Definition & chemical composition of types of asbestos
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What is asbestos?
This article gives a definition of asbestos and interestingly, explains that the name asbestos does not refer to a distinct mineral
species but it is a commercial term applied to fibrous varities of several minerals differing widely in composition,
strength, flexibility, and usefulness.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Definition of Asbestos Fibers
Asbestos is the name given to a number of mineral silicates.
The name asbestos does not refer to a distinct mineral
species but it is a commercial term applied to fibrous varities of several minerals differing widely in composition,
strength, flexibility, and usefulness.
Figure 2.2. View showing parallel fiber structure of asbestos vein, (Courtesy Johns-Manville-Corp.) [Click to enlarge any image]
Chemical and mineralogical studies show that asbestos is
of mineral origin. The most important variety is chrysotile,
which constitutes approximately 95 per cent of total world
prOduction. Its wide use is caused by the fact that its fibers
are generally strong, flexible, chemical resistant, and heat
resistant.
Other varieties of asbestos are crocidolite, amosite, anthophyllite,
tremolite, and actinolite; each has its own field
of utility. The chrysotile is classified as being of the serpentine
family. The others are of the amphibole family.
The amphibole groups of asbestos minerals were originally
known as hornblende, inasmuch as they were closely related
to the minerals tremolite and actinolite. This group is made
up of complex silicates.
Such varied types of fibers as tremolite and actinolite have widely different chemical structures.
Sometimes, it is difficult to identify these different minerals
except by x-ray. The amphibole group is interesting insofar
as chemical aspects are concerned;, although, weak fibrous
structures are present in the group..
Specific gravity of asbestos fibers ranges
from 2.5 for chrysotile to 3.3 for the other types.
Chemical Compostion of Chrysotile, Crocidolite, Amosite, Anthophyllite & Tremolite Asbestos
The chemical composition of the various types of asbestos
are
shown in Table 2.1.
Also see ASBESTOS FLOOR TILE COMPOSITION for an example of distinguishing between use of chrysotile and crocidolite asbestos in products.
TABLE 2.1. CHEMICAL COMPOSITION OF VARIOUS TYPES OF ASBESTOS * [ Click to enlarge or view details]
* Encyclopedia of Chemical Technology, Vol. 2, New York and London,
Intérscience Publisher (1948).
The chemical feature common to all asbestos is that they
are hydrated silicates The degree of hydration varies from
approximately one per cent in some types to as much as approximately
14 per cent in most kinds of chiysotile It generally accepted that asbestos is a metamorphic product
derived from certain types of silica-bearing minerals.
Asbestos is generally as dense as the rock in which it occurs but
it forms masses of fibers
Definition of Friable & Nonfriable Asbestos Materials
U.S. EPA Definition of Friable Asbestos
The US EPA in their "Asbestos NESHAP Adequately Wet Guidance" defines "friable asbestos material" as
Friable asbestos material is any material containing more than 1 percent asbestos as determined using Polarized Light Microscopy (PLM), that, when dry, can be crumbled, pulverized, or reduced to powder by hand pressure. - (EPA p, 3)
Properly defined in plain english, "friable" asbestos means that one can easily produce powdered material, for example by rubbing asbestos pipe insulation between one's fingers to produce a crumbly dust. In this regard your floor tiles are a mix of asbestos and vinyl or asphalt, and are not readily friable.
The definition of friable asbestos is important, because non-friable asbestos-containing material is less likely to be an asbestos hazard in buildings, unless it is mechanically ground or pulverized.
Asbestos is most-hazardous when it is friable. An example of friable asbestos include sprayed-on asbestos insulation.
U.S. EPA Definition of Nonfriable Asbestos Material
The US EPA in their "Asbestos NESHAP Adequately Wet Guidance" defines "nonfriable asbestos material" as
Nonfriable asbestos-containing material is any material containing more than 1 percent asbestos as determined by Polarized Light Microscopy (PLM) that, when dry, cannot be crumbled, pulverized, or reduced to powder by hand pressure. (Op Cit. p. 3)
By this definition, asphalt-asbestos and vinyl-abestos floor tiles are normally and virtually always non-friable materials.
Examples of nonfriable asbestos include asbestos-containing ceiling tiles, floor tiles, roof shingles, siding shingles, and similar "hard" materials. These materials do not release asbestos fibers unless they are disturbed or damaged, for example by drilling into an asbestos-containing ceiling tile or running power equipment or usign other means to aggressively break up and demolish asphalt-asbestos or vinyl-asbstos floor tiles.
Photo below: asbestos cement siding shingles: not friable.
You will see the importance of the distinction between friable and non-friable asbestos containing materials in articles about asbestos removal, encapsulation, or hazard reduction in buildings, such as
Asbestos is safe and legal to remain in homes or public buildings as long as the asbestos
materials are in good condition and the asbestos can not be released into the air. - US EPA [not currently easy to find this source - Ed. 2021]
THE BEST THING TO DO WITH ASBESTOS MATERIAL IN GOOD CONDITION IS TO LEAVE IT ALONE!
Disturbing it may create a health hazard where none existed before. - U.S. EPA, "Asbestos In The Home", retrieved 2021/07/17 original source: https://www.cpsc.gov/safety-education/safety-guides/home/asbestos-home
Photo below: friable asbestos debris from damaged paper asbestos duct insulation.
Watch out: some non-friable asbestos-containing materials such as floor tiles or paper duct insulation become friable either during demolition or in the case of paper asbestos insulating products the material may become friable due to exposure to water or weather.
Asbestos in buildings: Guidance for Service and Maintenance Personnel ("Custodial Brochure") (July 1985) - available by telephone from the TCSA
Guidance for Controlling Asbestos Containing Material in buildings ("Purple Book") (June 1985) - available by telephone from the TCSA
Fact Sheet/Press Release--EPA Releases Asbestos-in-Public-buildings Study and Recommendations to Congress: Extent and condition of asbestos containing materials in public and commercial buildings (February 1988) - available by telephone from the TCSA
NYC Health, ASBESTOS: WHAT YOU NEED TO KNOW [PDF] New York City, retrieved 2021/07/17 original source: https://www1.nyc.gov/assets/doh/downloads/pdf/edp/asbestos-faq.pdf
Excerpt: Asbestos, when intact, does not pose a risk to health. However, when asbestos-containing materials (ACMs)
are damaged or disturbed, asbestos fibers can be released into the air and breathed in.
US CPSC ASBESTOS IN THE HOME [PDF] (2021) U.S. Consumer Product Safety Commission, Washington D.C., retrieved 2021/07/17 original source: https://www.cpsc.gov/safety-education/safety-guides/home/asbestos-home
US EPA ASBESTOS IN YOUR HOME [PDF] (2010) U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
Above: Except from EPA's Guide to Demolition Practices (for non-friable asbestos material cateogies and handling) cited just below.
US EPA ASBESTOS NESHAP ADEQUATELY WET GUIDANCE, EPA340/1-90-019, [PDF] December 1990, U.S. ENVIRONMENTAL PROTECTION AGENCY, Office of Air Quality Planning and Standards, Stationary Source Compliance Division, Washington, DC 20460, original web source: http://www.epa.gov/region04/air/asbestos/awet.htm
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In addition to any citations in the article above, a full list is available on request.
[1] ASBESTOS HISTORY & PROPERTIES [Book online] D.V. Roasato, engineering consultant, Newton MA, Reinhold Publishing Co., NY, 1959, Library of Congress Catalog No. 59-12535. We are in process of re-publishing this interesting text. Excerpts & adaptations are found in InspectApedia.com articles on asbestos history, production & visual identification in and on buildings.
[2] "Asbestos in Plastic Compositions", A.B. Cummins, Modern Plastics [un-dated, pre 1952]
[3] "Asbestos in Your Home," Spokane County Air Pollution Control Authority, Spokane WA 509-477-4727 www.scapa.org provides a one-page image, a .pdf file drawing of a house warning of some possible sources of asbestos in the home. The sources are not ranked according to actual risk of releasing hazardous levels of airborne asbestos fibers and the list is useful but incomplete.
[4] The US EPA provides a sample list of asbestos containing products epa.gov/earth1r6/6pd/asbestos/asbmatl.htm
[5] "Characterization of asbestos exposure among
automotive mechanics servicing and handling
asbestos-containing materials", Gary Scott Dotson, University of South Florida, 1 June 2006, web search 3/9/2012 original source: scholarcommons.usf.edu/cgi/viewcontent.cgi?article=3505&context=etd [copy on file as /hazmat/Automotive_Asbestos_Exposure.pdf ].
[6] Asbestos Identification and Testing References
Asbestos Identification, Walter C.McCrone, McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed
the basis for current work by asbestos identification laboratories.
Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone
[6] ASBESTOS IN YOUR HOME U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
[7] Asbestos products and their history and use in various building materials such as asphalt and vinyl flooring includes discussion which draws on ASBESTOS, ITS INDUSTRIAL APPLICATIONS, ROSATO 1959, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print, text and images available at InspectAPedia.com).
[8] "Handling Asbestos-Containing roofing material - an update", Carl Good, NRCA Associate Executive Director, Professional Roofing, February 1992, p. 38-43
[9] EPA Guidance for Controlling Asbestos-Containing Materials in buildings, NIAST, National Institute on Abatement Sciences & Technology, [republishing EPA public documents] 1985 ed., Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460 Copy on file as ASBESTOS IN YOUR HOME - U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
Basic Information about Asbestos, US EPA, web search 08/17/2010, original source: http://www.epa.gov/asbestos/pubs/help.html
"Handling Asbestos-Containing roofing material - an update", Carl Good, NRCA Associate Executive Director, Professional Roofing, February 1992, p. 38-43
EPA Guidance for Controlling Asbestos-Containing Materials in buildings, NIAST, National Institute on Abatement Sciences & Technology, [republishing EPA public documents] 1985 ed., Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
EPA, ASBESTOS IN YOUR HOME [PDF] - U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460
[copy on file as /hazmat/Vermiculite_US_EPA.pdf/ Current Best Practices for Vermiculite Attic Insulation - May 2003, U.S. EPA
[copy on file as] /hazmat/Vermiculite_Health_Canada.pdf] Vermiculite Insulation Containing Amphibole Asbestos - September 2009, Health Canada
Managing Asbestos in Place, How to Develop and Maintain a Building Asbestos Operations and Maintenance (O&M) Program, U.S. EPA, web search 01/20/2011, original source: http://www.epa.gov/asbestos/pubs/management_in_place.html
Asbestos Strategies, Lessons Learned about Management and Use of Asbestos: Report of Findings and Recommendations on the Use and Management of Asbestos, 16 May 2003, US EPA, web search 01/20/2011, original source: http://www.epa.gov/asbestos/pubs/asbstrategiesrptgetf.pdf prepared by the: Global Environment & Technology Foundation, 7010 Little River Turnpike, Suite. 460, Annandale VA 20003
Other US EPA Publications on asbestos: web search 01/20/2011, see http://www.epa.gov/asbestos/pubs/pubs.html
In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Carson Dunlop Associates provides extensive home inspection education and report writing material. In gratitude we provide links to tsome Carson Dunlop Associates products and services.