POST a QUESTION or READ FAQs about how to identify fiberglass building insulation products & brands & how to distinguish fiberglass from other insulating material both by visual inspection and by forensic lab tests
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This article illustrates and describes common fiberglass insulation materials used in buildings and in building HVAC systems. We provide fiberglass photographs and identification examples because of frequent questions about how to recognize fiberglass building insulation products. This article series assists building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple
We include descriptive text of fiberglass building insulation products
to assist in identification of definite, probable, or possible asbestos materials in buildings. In some cases the resin binder which gives color to fiberglass insulation can permit an educated guess about the brand or manufacturer of the fiberglass insulation.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
How to Identify Fiberglass Insulation in Buildings
A Color Key to Identifying the Brand or Manufacturer of Fiberglass Building Insulation
Our photos show the colors (and manufacturers) and forms of fiberglass building 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.
Under the microscope fiberglass fibers are colorless or clear, as we illustrate later in this article. It is the resin binder used by the manufacturer to stick the fibers together into a batt or a chopped piece of insulation that give fiberglass insulation its characteristic color. For example this PHOTO of FIBERGLASS in the MICROSCOPE below in this article shows yellow resin binder.
Above: the black colored fiberglass is actually from staining.
Black Fiberglass Insulation?: No black fiberglass insulation product has turned up in any of our research. The black color on the fiberglass shown above is dirt from air bypass leaks.
You might see "black" on fiberglass insulation in these forms:
Asphalt-like black tarry substances may be used on the side of kraft paper or foil vapor retarders used to adhere the fiberglass batt to the paper or foil
Black-looking mold may grow on fiberglass that has become dirty and wet, or it may be found more often on the kraft paper attached to fiberglass if that material has been wet - don't blame the fiberglass, blame building leaks on this problem.
Dust and dirt may be deposited on fiberglass as air (containing house dust or other debris) moves past fiberglass at air leaks. In our photo at left you can see some pretty old and extensive thermal bypass leak stains on insulation in an attic.
Above: In our photo below you can see the very beginnings of such staining in the right-side center of a white fiberglass batt. If you see dirty or black marks on fiberglass it's probably a thermal bypass leak.>
Below: blue fiberglass.
Blue Fiberglass batts. The manufacturer of the light blue fiberglass shown below in photographs contributed by a reader (Anonymous) has not been identified. The closest match to this light blue insulation is the green fiberglass batt insulation produced by Johns Manville and shown above on this page.
Brown Fiberglass Insulation (above) is produced by EcoBatt® using the company's ECOSe technology, a plant-based binder provided as an alternative for the phenol/formaldehyde resin (PF) binder used in most glass mineral-wool products. Knauf Industries is a multi-national building & construction materials manufacturer with locations and offices world-wide. Contact: Knauf Industries, Website: http://www.knaufinsulation.com/
Green Fiberglass Insulation: John Mansville® has produced green fiberglass insulation like the green fiberglass batts we show above.
Pink Fiberglass Insulation: Owens Corning Pink Fiberglass® shown above is a registered trademark for their product line.
White Fiberglass Insulation: John Mansville produces white insulation (shown above) including their ComfortTherm® encapsulated batts.
Yellow Fiberglass Insulation: (shown above) most fiberglass insulation manufacturers other than the ones listed below produce yellow fiberglass insulation. (China Fiberglass Insulation Manufacturers, for example.)
Insulating Characteristics of Fiberglass Insulating Batts & Chopped Fiberglass Insulation
Fiberglass building insulation typically has an "R" value of 3.14 per inch. Shown above, a white fiberglass insulation batt.
Shown below, pink chopped fiberglass insulation installed as a loose-fill or more-likely blown-in fiberglass insulation product.
[Click to enlarge any image]
Does Fiberglass Insulation Contain Asbestos?
Fiberglass Insulation is a glass fiber product and does not normally contain asbestos, though it can become contaminated by rodents, insects, or mold, and especially if damaged, disturbed, and exposed to a living space, it can become a source of problem particles, as we discuss at FIBERGLASS HAZARDS.
Forensic Laboratory Photographs of Building Insulation
Laboratory photos of fiberglass can often assist in determining where fiberglass fragments and debris are originating.
The microscope lets us identify the color of resin binders which may enable us to match the colors in fiberglass dust to the colors and binders of samples taken from known fiberglass insulation reservoirs in the building.
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.
A Guide to Health and Debris Characteristics of New versus Old Fiberglass Building Insulation
Some research argues that fiberglass particles are larger than and less dangerous than asbestos. However
many small fiberglass particles may be in indoor air but may be below the threshold of some common measurement methods.
See FIBERGLASS HAZARDS in buildings.
For more information about fiberglass as an indoor air quality concern see:
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
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
Don't confuse fiberglass insulation with asbestos insulation
Fiberglass insulation is not and should not be confused with asbestos nor with the
well-studied health hazards associated with exposure to asbestos fibers or dust.
Information about possible hazards of fiberglass insulation
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(Jan 23, 2015) ron said:
I want to use fiberglass batts in the beam space between my basement and first floor with the paper backing on the upper floor side. Is this advisable?
Sounds reasonable and pretty common Ron. Keep the vapor barrier on the warm side. If you need to staple up something to not breathe fiberglass dust (that is if you're not going to drywall the ceiling) try housewrap.
(Mar 15, 2015) A.J. Rayner said:
can lass insulation go bad
Fiberglass is basically glass - spun into fibers, bound with a resin and sometimes backed on one side with foil or paper. It's rather inert.
What "goes bad" is more what happens if the insulation is
"The Elimination of Unsafe Guardrails, a Progress Report," Elliott O. Stephenson, Building Standards, March-April 1993
"Are Functional Handrails Within Our Grasp" Jake Pauls, Building Standards, January-February 1991
Access Ramp building codes:
Access Ramp Standards:
ADA (Americans with Disabilities Act), Public Law 101-336. 7/26/90 is very often cited by other sources for good design of stairs and ramps etc. even where disabled individuals are not the design target.
ANSI A117.4 Accessible and Usable buildings and Facilities (earlier version was incorporated into the ADA)
ASTM F 1637, Standard Practice for Safe Walking Surfaces, (Similar to the above standards)
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).
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
Brick Nogging, Historical Investigation and Contemporary Repair, Construction Specifier, April 2006. Historical use of brick in timber-framed buildings, drawing on the investigations of the Kent Tavern in Calais, VT.
"Brick nogging is a European method of construction which was brought to the new world in the early-nineteenth century. It was a common construction method that employed masonry as infill between the vertical uprights of wood framing." -- quoting the web article review.
Building Research Council, BRC, nee Small Homes Council, SHC, School of Architecture, University of Illinois at Urbana-Champaign, brc.arch.uiuc.edu. "The Small Homes Council (our original name) was organized in 1944 during the war at the request of the President of the University of Illinois to consider the role of the university in meeting the demand for housing in the United States. Soldiers would be coming home after the war and would be needing good low-cost housing. ... In 1993, the Council became part of the School of Architecture, and since then has been known as the School of Architecture-Building Research Council. ... The Council's researchers answered many critical questions that would affect the quality of the nation's housing stock.
How could homes be designed and built more efficiently?
What kinds of construction and production techniques worked well and which did not?
How did people use different kinds of spaces in their homes?
What roles did community planning, zoning, and interior design play in how neighborhoods worked
"Energy Savers: Whole-House Supply Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Supply_Vent.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11880?print
"Energy Savers: Whole-House Exhaust Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Exhaust.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11870
"Energy Savers: Ventilation [copy on file as /interiors/Energy_Savers_Ventilation.pdf ] - ", U.S. Department of Energy
"Energy Savers: Natural Ventilation [copy on file as /interiors/Energy_Savers_Natural_Ventilation.pdf ] - ", U.S. Department of Energy
"Energy Savers: Energy Recovery Ventilation Systems [copy on file as /interiors/Energy_Savers_Energy_Recovery_Venting.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11900
"Energy Savers: Detecting Air Leaks [copy on file as /interiors/Energy_Savers_Detect_Air_Leaks.pdf ] - ", U.S. Department of Energy
"Energy Savers: Air Sealing [copy on file as /interiors/Energy_Savers_Air_Sealing_1.pdf ] - ", U.S. Department of Energy
Falls and Related Injuries: Slips, Trips, Missteps, and Their Consequences, Lawyers & Judges Publishing, (June 2002), ISBN-10: 0913875430 ISBN-13: 978-0913875438 "Falls in the home and public places are the second leading cause of unintentional injury deaths in the United States, but are overlooked in most literature. This book is unique in that it is entirely devoted to falls. Of use to primary care physicians, nurses, insurance adjusters, architects, writers of building codes, attorneys, or anyone who cares for the elderly, this book will tell you how, why, and when people will likely fall, what most likely will be injured, and how such injuries come about. "
Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
Humidity: What indoor humidity should we maintain in order to avoid a mold problem?
Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
Pergo AB, division of Perstorp AB, is a Swedish manufacturer or modern laminate flooring products. Information about the U.S. company can be found at http://www.pergo.com where we obtained historical data used in our discussion of the age of flooring materials in buildings.
Piquet Wall Construction: See this photo of
piquet wall construction - involving timber-framed wall construction with long top girts, diagonal timber bracing, and small diameter logs
placed vertically along with concrete chinking to fill in the wall plane.
Plank House Construction: weblog from plankhouse.wordpress.com/2009/01/25/plank-house-construction/ and where plank houses were built by native Americans, see
Large 1:6 Scale Plank House Construction / P8094228,
Photographer: Mike Meuser
06/12/2007 documented at yurokplankhouse.com where scale model Museum quality Yurok Plank Houses are being sold to raise money for the Blue Creek - Ah Pah Traditional Yurok Village project.
Re-Bath, tub lining products is a bath tub relining manufacturer and distributor located in Tempe, Arizona - see rebath.com
Rubblestone Wall Filler: See this Lartigue House using exterior-exposed rubblestone filler between vertical timbers of a post and beam-framed Canadian building.
Slips, Trips, Missteps and Their Consequences, Second Edition, Gary M. Bakken, H. Harvey Cohen,A. S. Hyde, Jon R. Abele, ISBN-13: 978-1-933264-01-1 or
ISBN 10: 1-933264-01-2,
available from the publisher, Lawyers ^ Judges Publishing Company,Inc., www.lawyersandjudges.com email@example.com and also from the InspectAPedia Bookstore (Amazon.com)
The Stairway Manufacturers' Association, (877) 500-5759, provides a pictorial guide to the stair and railing portion of the International Residential Code. [copy on file as http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf ] -
Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
Manufactured & Modular Homes: Modular Building Systems Association, MBSA, modularhousing.com, is a trade association promoting and providing links to contact modular builders in North America. Also see the Manufactured Home Owners Association, MHOAA, at www.mhoaa.us. The Manufactured Home Owners Association of America is a National Organization dedicated to the protection of the rights of all people living in Manufactured Housing in the United States.
Mold-Resistant Building Practices, advice from an expert on how to prevent mold after a building flood and how to prevent mold growth in buildings by selection of building materials and by anti-mold construction details.
Slips, Trips, Missteps and Their Consequences, Second Edition, Gary M. Bakken, H. Harvey Cohen,A. S. Hyde, Jon R. Abele, ISBN-13: 978-1-933264-01-1 or ISBN 10: 1-933264-01-2, available from the publisher, Lawyers & Judges Publishing Company,Inc., www.lawyersandjudges.com firstname.lastname@example.org and also from the InspectAPedia Bookstore (Amazon.com)
Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones