Indoor Use of Foil Faced Polyisocyanurate Foam Insulation: Hazards? InspectAPedia® -
Are there any health hazards associated with applying rigid foil-faced insulating foam (polyisocyanurate insulation) on the interior side of walls?
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This article discusses the question: are there any health hazards associated with applying rigid foil-faced insulating foam (polyisocyanurate insulation) on the interior side of walls? Sketch at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
The question-and-answer article about the indoor use of foil faced insulating foam found just board below paraphrases, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.
Is Foil Faced Polyisocyanurate Foam Insulation Hazardous when Used Indoors?
Are there any health hazards associated with applying rigid foil-faced polyisocyanurate insulation on the inside of the existing walls of a living space?
I am aware that these insulations give off toxic gases as they burn. The question in my mind is whether they are safe on a day-to-day basis within the building envelope with an air change rate of say 0.75 ACH per hour? -- R.H. Mendocino CA
Our photograph (above left) shows Celotex Super Tuff-R polyisocyanurate insulating board used indoors.
Answer:
Rigid polyisocyanurate insulation is foamed from freon gas, a fluorinated hydrocarbon often used as a refrigerant and until the early 1980's, as a propellant in aerosols. [Currently non HFC gases are used for foam insulation production --DF] The earlier-used Freon gas family and modern refrigerants are inert gases and are considered non-toxic, except in very high concentrations of over 1000 ppm [at which point even an inert gas can cause asphyxiation].
The small quantities of gas that will be released from this foam insulating board [until it has "cured" and stopped outgassing] by diffusion or rupture are not considered a health hazard by the several health authorities we contacted. The upper-limit service temperature for this type of foam is 250 degF.
In uncontrolled combustion, all flammable building materials release high levels of toxic fumes. The National Fire Protection Association (NFPA) recommends that all insulation products be contained behind drywall or a suitable fire retarder. A check with your local building officials is almost certainly going to confirm that foam insulation products may not be left exposed in the living area.
In our sketch at page top you will see that the solid foam insulating board in that illustration is placed on the building interior wall surface, but it has been covered with furring strips and then drywall. The furring strips provide a dead air space, increasing the wall's R-value, and the space is in some conditions also used for routing wiring.
The hazard with foam insulation products is of production of toxic fumes or smoke release during a building fire, not outgassing during normal building conditions.
Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
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Solar Age Magazine was the official publication of the American Solar Energy Society. The contemporary solar energy magazine associated with the Society is Solar Today. "Established in 1954, the nonprofit American Solar Energy Society (ASES) is the nation's leading association of solar professionals & advocates. Our mission is to inspire an era of energy innovation and speed the transition to a sustainable energy economy. We advance education, research and policy. Leading for more than 50 years.
ASES leads national efforts to increase the use of solar energy, energy efficiency and other sustainable technologies in the U.S. We publish the award-winning SOLAR TODAY magazine, organize and present the ASES National Solar Conference and lead the ASES National Solar Tour – the largest grassroots solar event in the world."
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
Excerpts with updates and annotations expanding the original Best Practices Guide text can be found in the online review and book summary at BEST CONSTRUCTION PRACTICES GUIDE and also at DECK & PORCH CONSTRUCTION, at INDOOR AIR QUALITY IMPROVEMENT GUIDE, and in other articles found at InspectAPedia.com such as HOUSEWRAP AIR & VAPOR BARRIERS, SOUND CONTROL in BUILDINGS, and other topics.
Tuff-R™ and Super Tuff-R™, Dow Building Solutions, have an R-value of R 6.5 per inch. Note that the R-value of this insulating board is increased to R-9.3 per inch if construction includes a 3/4" air space. These are closed-cell polyisocyanurate insulating foam core board products. The foam core is sandwiched between a choice of exterior faces including aluminum foil, tri-plex aluminum foil, or polyester kraft paper combined with reinforced aluminum foil. One board side is blue, the other is radiant aluminum foil. These products must be covered with a minimum of 1/2" drywall or equivalent thermal barrier in building applications.
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