Fiberglass Particle Identification in the Fiberglass Test Laboratory
LAB IDENTIFICATION OF FIBERGLASS - CONTENTS: Microscopic identification of fiberglass - Lab and field photographs of fiberglass insulation products. Guide to fiberglass fragment identification in the laboratory
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Lab procedures for fiberglass dust testing: This document provides forensic laboratory procedural details for the laboratory identification of fiberglass hazards in air or in settled dust samples collected in residential and light-commercial buildings.
Laboratory Identification of Fiberglass Fibers & Fragments
Fiberglass fragments in air, dust, or material samples are easily identified in the forensic laboratory using light and polarized light microscopy and
common slide preparation techniques.
While glass fibers can be identified using Cargille(R) certified refractive index liquids, it is easier and faster to examine fibers prepared in almost any common slide mounting solution by looking for the following features:
Smooth sided manmade fibers which may appear in a wide variety of diameters and lengths, but with a characteristic concoidal fracture on the fiber end is key in laboratory identification of fiberglass fragments in air samples or settled dust samples from buildings where screening for fiberglass dust is required
Presence of colored resin binder on fiber lengths or where fibers cross is another identifying characteristic of fiberglass insulation
The disappearance of these fiberglass fibers from view in a light microscope when viewed with crossed polars also is used to confirm that glass fibers are present
Presence of concoidal fractures on the ends of fibers is evidence of glass or fiberglass
The two lab photographs of fiberglass insulation just above show, from left, the characteristic concoidal fracture at the end of a fiberglass fiber,
and resinous material used as a binder in fiberglass insulation. The resin binder in fiberglass insulation can appear in various colors and which gives
fiberglass its individual characteristic color.
Determining the source of fiberglass particles found in a building: It may be possible to identify the manufacturer of or at least the source of fiberglass fibers found
in a building by comparing the color of resin identified in the microscope with colors observed by visual inspection of fiberglass installed
in different building areas.
Identifying fiberglass resins and mineral wool insulation: The left hand lab photo of fiberglass show below provides two examples of resinous binder in fiberglass insulation at a lower magnification of about
300x, with the left, triangular resin particle having been bound to two intersecting glass fibers.
Notice the considerable variation in fiberglass
fiber diameter in this photo - the fibers in this photo might be from different sources as not only are they characteristically different by metrics,
but their resins are of different color.
Problems in identifying very small fiberglass fragments in air and dust samples: Our own field investigations find that fiberglass particles are quite common in
Unless the forensic particle laboratory is making a point of counting small fiberglass fragments in indoor air or dust samples, only a large-particle count may be provided and the presence and potential effects of fiberglass dust may be underestimated.
Furthermore, proper lab procedure and use of mountants with an appropriate refractive index to see glass fragments is critical as otherwise such particles may simply be invisible when viewed using conventional slide preparation methods.
Mineral wool insulation: The right hand photo shown below shows
displays a resin binder and thin, varying-diameter fibers of glass mineral wool insulation.
Under polarized light using crossed polars, the glass fibers in these photos will simply disappear from view. (photo not shown - phase contrast microscopy or use of special mounting fluids with an appropriate refractive index may be needed especially to identify small fiberglass fragments.)
Photographs of Unbonded Fiberglass Insulation - "Blowing Wools"
Above (left) we show a macro photograph of white blown-in unbonded InsulSafe® building insulation sold by CertainTeed and provided by a homeowner who asked our lab to study dust samples from her home. At above right is the same insulation shown in the stereo microscope at about 20x, and below the same material is magnified to 720x.
Identifying Contents of House Dust to Screen for Building Insulation
Above (left) we show a 720x micro-photograph of white blown-in unbonded InsulSafe® building insulation sold by CertainTeed. At above right our photo shows the dominant particles in the dust sample from the home under study. Magnified to 720x the fibers we found were primarily cotton, with some linen and a few synthetic fabric fibers. There was virtually none of the insulation fibers provided for comparison (above left) as a possible source of dust in the home.
Above (left) a client photo shows a heavy and rapid dust accumulation on building surfaces. At above right our lab photo shows that the prime contents of the dust were fabric fibers and starch granules, not building insulation in this case. - DF & WW 6/2010.
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Fiberglass carcinogenicity: "Glass Wool Fibers Expert Panel Report, Part B - Recommendation for Listing Status for Glass Wool Fibers and Scientific Justification for the Recommendation", The Report on Carcinogens (RoC) expert panel for glass wool fibers exposures met at the Sheraton Chapel Hill Hotel, Chapel Hill, North Carolina on June 9-10, 2009, to peer review the draft background document on glass wool fibers exposures and make a recommendation for listing status in the 12th Edition of the RoC. The National Institute of Environmental Health Sciences is one of the National Institutes of Health within the U.S. Department of Health and Human Services. The National Toxicology Program is headquartered on the NIEHS campus in Research Triangle Park, NC. The National Institute of Environmental Health Sciences is one of the National Institutes of Health within the U.S. Department of Health and Human Services. The National Toxicology Program is headquartered on the NIEHS campus in Research Triangle Park, NC.
Following a discussion of the body of knowledge, the expert panel reviewed the RoC listing criteria and made its recommendation. The expert panel recommended by a vote of 8 yes/0 no that glass wool fibers, with the exception of special fibers of concern (characterized physically below), should not be classified either as known to be a human carcinogen or reasonably anticipated to be a human carcinogen. The expert panel also recommended by a vote of 7 yes/0 no/1 abstention, based on sufficient evidence of carcinogenicity in well-conducted animal inhalation studies, that special-purpose glass fibers with the physical characteristics as follows longer, thinner, less soluble fibers (for 1 example, > 15 μm length with a kdis of < 100 ng/cm2/h) are reasonably anticipated to be a human carcinogen for the listing status in the RoC. The major considerations discussed that led the panel to its recommendation include the observations of tumors in multiple species of animals (rats and hamsters). Both inhalation and intraperitoneal routes of exposure produced tumors, although inhalation was considered more relevant for humans.
Fiberglass insulation mold: occurrence of mold contamination in fiberglass insulation can be impossible to see with the naked eye, but can be significant
World Health Organization International Agency for Research on Cancer - IARC Monographs on the Evaluation of Carcinogenic Risks to Humans - VOL 81 Man-Made Vitreous Fibers, 2002, IARCPress, Lyon France, pi-ii-cover-isbn.qxd 06/12/02 14:15 Page i - World Health Organization, 1/21/1998. - Fiberglass insulation is an example of what IARC refers to as man made vitreous fiber - inorganic fibers made primarily from glass, rock, minerals, slag, and processed inorganic oxides. This article provides enormous detail about fiberglass and other vitreous fibers, and includes fiberglass exposure data.
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81.pdf - the article (large PDF over 6MB)
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6A.pdf - article details
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6C.pdf - studies of cancer in experimental animals in re vitreous fibers such as fiberglass;
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6E.pdf - summary of data reported & evaluation
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6F.pdf for the article references
To search the IARC monographs on various environmental concerns and carcinogens, use http://monographs.iarc.fr/ENG/Monographs/PDFs/index.php
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home",
U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [ copy on file as /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [on file as /sickhouse/EPA_Moho_Guia_sp.pdf - - en Espanol
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