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This article discusses polyurethane foam insulation outgassing, the initial degradation in the R-value of foam insulation, and other properties. Our photo (page top) shows icynene foam insulation that oozed into an attic space after being blown onto the building gable-end wall. Fiberglass insulation is also visible at the left foreground.

Readers should see INSULATION & VENTILATION INSPECTION & IMPROVEMENT and Icynene Foam Spray Insulation. If you are having trouble determining what type of foam insulation product has been installed in a building, see How to Make a Sure Distinction Among UFFI, Icynene, and Latex Foam Insulations for more detail on the identification of these products in the field. And we discuss the reduced risk of mold where icynene is in crawl spaces at Mold risk in Icynene Foam Insulation. See Urea Formaldehyde Foam Insulation UFFI for an example of an earlier set of problems with UFFI.

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Q&A: Rate of Outgassing of Foam Insulation; relationship between thermal performance of foam insulation and time degradation

The link to the original Q&A article in PDF form immediately below is followed by an expanded/updated online version of this article.

• "Urethane Outgassing" - Q&A article, Solar Age, April 1984 - PDF version, Use your browser's back button to return to this page

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

Polyurethane Foam R-Value Loss Mechanisms

Question:

Thank you for an excellent article on building insulation materials (Solar Age, "Building it Right", 11/83, also see our complete guide to insulation at INSULATION & VENTILATION INSPECTION & IMPROVEMENT). Of all the areas in the field of energy-efficient materials and construction, none is so fraught with misinformation as insulation.

After many inquiries to manufacturers and extruders of rigid foam insulation products I have been unable to find accurate information as to the rate of outgassing in foam building insulation, or the relationship between thermal performance of foam insulation and time. Have you found any better information than I have? -- Michael Luttrell, Napa CA

Answer:

Polyurethane foams lose R-value by two mechanisms: air infiltrating the foam and fluorocarbon gas diffusing out of the foam insulation.

Immediately after manufacture, polyurethane foam increases in conductivity quite rapidly. The rate of increase in foam insulating board conductivity (which is equivalent to a loss in the foam insulating board's R-value) ultimately stabilizes at a plateau level, which can remain unchanged after more than 10 years.

Since most of the change in foam insulating board R-value occurs in the first two to two-and-a-half years, manufacturers of residential foam insulating products are required to publish a two-year aged R-value.

The rate and degree of R-value drift in foam insulating board depends on many factors such as foam cell size, closed cell foam content, foam board material thickness, and foam board density.

The main factors, though, are the permeance of the foam board facing and how well it is bonded to the foam itself. Metal foam insulating board facings bonded to the wet foam at the time of manufacture (generally aluminum foil) appear to yield the highest R-values.

Through extensive testing at independent laboratories, Celotex Corp. has established that its foil-faced Thermax™ foam board insulation remains stable at about R-7.2 per inch at 75 degF mean temperature for at least five years of aging.

In its bulletin U108, the Urethane Division of the Society of the Plastics Industry lists the stabilized R-value for unfaced foam insulating board or those with gas-permeable facings at R5.6 to R 6.2 per inch of thickness. Consult with the manufacturers for information on specific foam insulating board products.

More Details about Polyurethane, Urethane, and Icynene Foam Insulation Products

Fom our detailed article at Icynene Foam Spray Insulation:

Icynene® foam insulation (and similar products) is a spray-in-place, injected through openings, or pour-in expanding-foam insulation product. Other water borne foam spray insulation products, including some latex-foams, are available.

• Wind leakage resistance: both open cell foams and closed cell foam insulation products lose less of their R-value when exposed to wind than do some other insulating products such as fiberglass batts. Spray Foam Systems asserts that the R-value of urethane foam (this is not an Icynene® product) drops from R 19 to R 18 while fiberglass batt insulating drops from R19 to R7 (presuming these are both applied in a 6" thickness). U.S. Department of Energy studies cite air infiltration in buildings as responsible for 40% of the energy lost in homes (surely varying depending on tightness of construction, house age, etc.)
• Dimensional stability: this product does not shrink or settle (see Cellulose loose fill insulation and Urea Formaldehyde Foam Insulation UFFI). At How to Make a Sure Distinction Among UFFI, Icynene, and Latex Foam Insulations we demonstrate a compression test of this material to show its elasticity.
• Icynene® foam and other water-borne foam insulation systems use a water-based solvent, not formaldehyde, or other chemicals associated with prior problem-foam products such as CFCs and HCFCs. Initial foam curing occurs in minutes. When these foams have fully cured (about a month) no VOCs should be detected associated with these foam products. See  Urea Formaldehyde Foam Insulation UFFI for an example of an earlier set of problems with UFFI.
• Fire safety protection: foam insulation products can be hazardous in a building fire and in general must be protected from direct exposure in occupied spaces (such as covering with drywall) in order to assure that potentially dangerous gases are not released into the living area during a fire. See the industry's fire safety guidelines for details, an example of which is provided in this fire safety bulletin from the polyurethanes industry.

• See How to Make a Sure Distinction Among UFFI, Icynene, and Latex Foam Insulations for more detail on the identification of these individual foam insulation products in the field
• See  Mold in Fiberglass Insulation and  Mold in Foam Insulation for details about mold problems in building insulation.
• See INSULATION INSPECTION & IMPROVEMENT for details about foam and other building insulation types;
• See FIBERGLASS HAZARDS for a discussion of mold problems in fiberglass insulation;
• See Mold On Foam Insulation for a discussion of when and why we find mold growth on foam insulating materials like foam board and air handler foam insulating board.

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ASBESTOS IDENTIFICATION IN BUILDINGS

INSULATION INSPECTION & IMPROVEMENT
Insulation Material Identification Guide
Asbestos-Free Insulation Materials
  Balsam Wool Batt Insulation
  Cotton Insulating Batts
  Cellulose loose fill insulation
  Concrete insulation, light-weight
  Fiberglass Insulation
  Foam Board Insulation
  Foam Insulation Types - Visual Id
  Homasote & Other Insulating Board
  Icynene Foam Spray Insulation
  Insects & Foam Insulation
  Mineral Wool - Rock Wool Insulation
  Mold in Fiberglass Insulation
  Mold in Foam Insulation
  Paper Duct Insulation
  Perlite Insulation
  POLYISOCYANURATE FOAM INSULATION
  POLYSTYRENE FOAM INSULATION
  RADIANT BARRIERS
  RIGID FOAM USE INDOORS
  Urea Formaldehyde Foam Insulation UFFI
  URETHANE FOAM Deterioration, Outgassing
  Vermiculite Insulation
HEAT LOSS CALCULATIONS
INSULATION LOCATION for BASEMENTS
INSULATION LOCATION for CAPES, CRAWLSPACES
INSULATION for GREENHOUSE or SOLARIUM
INSULATION MATERIAL IDENTIFICATION GUIDE
INSULATION R-Values & Properties
ASBESTOS: Photo Guide to Materials / Products
Mold Growth Resistance of Foam Insulation
Table of Properties of Insulating Materials
IDENTIFICATION of ASBESTOS in BUILDINGS
ROT, FUNGUS, TERMITES
  TERMITE SHIELDS vs TERMITICIDE

• Icynene Corporation maintains a website with information about Icynene® foam insulation products, applications, etc. and is located in Mississauga, Ontario, Canada Tel: 905.363.4040 Toll Free: 800.758.7325
• Icynene Foam Insulation Spray MSDS
• Icynene Foam Insulation Pour formula MSDS
• Spray Foam Systems (urethane foam insulation products)
• API Alliance for the Polyurethanes Industry Fire Safety Guidelines for Use of Rigid Polyurethane and Polyisocyanurate foam Insulation in building Construction (.pdf file)

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More Information on Building Diagnostic Inspections and Repairs

• Asbestos: How to find and recognize asbestos in Buildings - visual inspection methods, list of common asbestos-containing materials
• Asbestos HVAC Ducts and Flues field identification photos and guide
• Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
• Enviro-Scare: Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues
• Dust from the World Trade Center collapse following the 9/11/01 attack: the lower floors of this building contained spray-on fire-proofing asbestos materials.
• Asbestos Information Links: Asbestos Detection, Testing, Recognition, Hazards, Field Photos, and Information Sources, including health-related links such as legal services and information about mesothelioma and other cancers.
• 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

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