Fiberglass Hazards in Indoor Air, Dust, HVAC ducts, and Building Insulation InspectAPedia® -
How to recognize fiberglass insulation materials in buildings
Microscopic identification of fiberglass insulation fragments
Health concerns of fiberglass exposure
Mold hazards in fiberglass insulation
Fiberglass exposure hazard reference list
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This document provides information about how to identify fiberglass insulation in buildings and fiberglass hazards and fiberglass insulation contamination issues in residential and light-commercial buildings.
How to Identify or Recognize Fiberglass Insulation in Buildings
The fiberglass research literature is replete with studies indicating that there are no health hazards associated with airborne fiberglass particles, and with other studies reaching quite the opposite conclusion. We recommend that readers examine carefully the methodology used in such studies, the expertise of the researchers, and the sources financing of such work.
Based on literature review as well as both field and laboratory experience, it is reasonable to claim that large particles of fiberglass are far more likely to be a respiratory or skin irritant than a carcinogen or other more serious health hazard. However some of our field and lab inspections detect very small, even sub-micron sized particles which are traced to building insulation. These much smaller particles may indeed be a health hazard, and may be entirely omitted or simply missed by some laboratories charged with reporting on the level of fiberglass in building air or dust.
Here we discuss the recognition of types of fiberglass insulation in buildings, other fiberglass particle sources, and some possible health concerns that involve these materials.
What does fiberglass building insulation look like & what are the colors of fiberglass insulation?
Fiberglass building insulation is commonly installed in batts or chopped forms and may be yellow, pink, green, or white in color as is shown in these four photographs. While this material is not and should not be confused with asbestos nor with the well-studied health hazards associated with exposure to asbestos fibers or dust, our separate article on Airborne Fiberglass Building Insulation Hazards and HVAC duct work insulation hazards contains additional discussion about possible air quality and health concerns which may be associated with exposure to fiberglass dust.
Where else do we find fiberglass in buildings besides floor, wall and attic insulation?
Fiberglass duct insulation material appears in several forms in heating and air conditioning systems in both ducts and air handlers themselves.
The most common uses of fiberglass insulating material in HVAC systems includes the cases listed below.
The annotated duct system photographs shown in the article cited below will permit any careful observer to identify the most common types of fiberglass HVAC duct materials.
We provide these (C)-protected photographs of fiberglass insulated ducts and HVAC components to aid in recognition of these materials.
Our detailed article on how to recognize fiberglass duct insulation and its characteristics and hazards can be read in its entirety at Recognizing Fiberglass Duct Insulation.
What are the Problems with Identifying Fiberglass Hazards in Buildings?
Special challenges face consumers requesting lab services for identification of 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.
Our photograph (left) shows a typical fiberglass insulation fiber with droplets of resin binder attached. It's easy to identify large fiberglass fibers in transmitted-light microscopy.
But identification of very small fiberglass fragments in a building dust or air sample can be difficult to detect unless the microscopist is trained and looking for that material, and special methods such as use of phase contrast may be needed.
Binder Resins in Fiberglass Insulation Help Trace Source
Observing the color of a fiberglass bonding resin can help trace particular fiberglass in a building air or dust sample back to its source.
Other fiberglass products, such as this Certainteed unbonded blowing wool (fiberglass) lack a characteristic resin. Interestingly in this client-provided sample of nearly-new blown-in fiberglass insulation we found very few small fiber fragments. Dust tested from that home was also low in fiberglass fragments.
The common errors which result in failing to detect small fiberglass particles in building air and dust are discussed in detail at Lab Identification of Fiberglass
In that article we also discuss techniques which permit the forensic microscopy lab to identify the source or reservoir of particular fiberglass fragments in a building, sorting out among many possible fiber sources to pinpoint the particular problem such as damaged building insulation, damaged HVAC duct work, or other particle sources.
We also discuss how to distinguish among types of insulating and other fibers, comparing various types of fiberglass insulation, mineral wool insulation, asbestos insulation, and other fibers.
Frequent presence of fiberglass fragments in air and some dust samples, suggests that an HVAC duct system or exposed fiberglass
insulation in the building may be contributing unwanted and potentially unsafe levels of these fibers.
This discussion can be read in its entirety at Fiberglass Detection in Building Air.
We have also detected high levels of problematic mold in
fiberglass building insulation where other mold reservoirs were either not present or had been
previously removed.
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"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.
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.
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
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
For more information about fiberglass as an indoor air quality concern see:
BASEMENT MOLD includes examples of moldy fiberglass insulation found in basements
CRAWLSPACE MOLD includes additional examples of moldy fiberglass insulation found in
crawl spaces
Insulation Identification Photographs - Fiberglass insulation photos, yellow, pink, green, white fiberglass identification in building attics, walls, ducts, other locations
Mold in Fiberglass, when, why, and how fiberglass becomes a reservoir of problem mold in buildings.
Lab Identification of Fiberglass photographs and text assist in laboratory identification of fiberglass fibers and fragments in air, dust, or material samples in the laboratory using forensic microscopic techniques.
Asbestos: How to find and recognize asbestos in buildings - visual inspection methods, list of common asbestos-containing materials
More Information on Building Diagnostic Inspections and Repairs
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