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Guide to asbestos-free building insulation products: this non-asbestos insulation article illustrates and describes common insulation materials that would not be expected to contain asbestos. We include photographs that can help you identify common building materials that are unlikely to have ever contained asbestos.
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.
Asbestos-Free Insulation Materials: Examples of materials that do not commonly contain asbestos but might be mistaken for asbestos-containing substances
Our photo at above left is of blown-in cellulose insulation. The links just below under the green heading provide articles describing building insulation materials that would not be expected to contain asbestos.
Our page top photo shows mineral wool insulation in a building attic - mineral wool or "rock wool" is not expected to be an asbestos-containing material.
Balsam wool is a wood or cellulose product discussed in detail at Balsam Wool Batt Insulation. See that article for more about asbestos questions concerning this wood product material.
These non-asbestos insulations include cellulosic insulations such as loose-fill cellulose and balsam wool batts, cotton insulation, fiberglass insulation, mineral wool insulation, slag wool insulation, and rock wool insulation.
Other older building insulation materials such as corn cobs, newspaper, bricks, and simple reflective barriers using aluminum foil also would not be expected to contain asbestos.
Solid Foam Product Insulating Products - Rigid Polystyrene, Polyurethane, Polyisocyanurate Insulation products will not contain asbestos fibers and most of these products are rather mold resistant, possibly because of their chemistry or because closed-cell foam insulations simply do no take up and hold the moisture that is required for active mold growth on or in building insulations or surfaces.
What are the Insulation R-Values of Foam Insulation Boards?
Expanded, extruded, and cut bead polystyrene insulation products have an R-value of about 4.0 per inch of thickness.
Typical exterior foam board building insulation sheets have an R-value of 2.64 per inch. Expanded polyurethane building insulation products have an R-value of about 5.0 per inch of thickness. Expanded polyurethane insulation expanded using the refrigerant gas has an R-value of about 6.25 per inch. Polyisocyanurate insulation products have an R-value of about 7.04 per inch.[ASHRAE Fundamentals Handbook.]
Mold on Foam Insulation: Explanation & Assessment of the Growth of Mold on Solid Foam Insulation Products
However we have observed surface mold growth on polystyrene foam board insulation. In those instances where we found mold on foam rigid insulating boards it has sometimes been due to the combination of exposure to wet conditions and the presence of organic dust and debris on the surface of the foam.
We've seen these mold-friendly conditions producing mold on foam insulation materials (and on even less mold-friendly materials like metal or glass or un-painted masonry block foundation walls) where the insulation surface was wet, kept in a wet or very humid environment, and was dusty or dirty.
This is a probable explanation for the frequent discovery of mold in building air conditioning air handlers or blower compartments. In air handlers condensate over spray is often blown around in the blower compartment.
There are mold species that can grow on just about anything; but the presence of hair, skin cells, and other organic debris on building surfaces may explain why we find more mold growth on foam board insulation in one location and no mold growth on the same building product used somewhere else. Usually the mold we identify in building air handlers is a species of Cladosporium sp. - called the "king of molds" because molds in this family are so widespread outdoors.
Cladosporium sp. is not without its own health concerns for some building occupants, but when this mold is found indoors it may be more important to determine why it is there and therefore to determine the chances that other, more toxic and more easily airborne mold genera/species are present in the same building.
Though we sometimes find fungal growth in buildings that looks a lot like this substance, it would be very odd for it to appear so extensively and so uniformly as the foam insulation shown in this photo.
This is a sprayed-on icynene foam insulation project that was completed in a crawlspace. Because the work area was tight, it was difficult for the foam spraying technician to work meticulously but s/he did a pretty nice job.
Using a combination of visual inspection and smoke testing we found only two openings in the foam blanket that were permitting air movement from the crawl space up into the living space. Overall it was an effective installation.
In the ARTICLE INDEX given below we include more articles helpful if you need to identify
Asbestos: How to find and recognize asbestos in Buildings - visual inspection methods, list of common asbestos-containing materialsAsbestos HVAC Ducts and Flues field identification photos and guide 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
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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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.
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