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.

Rate of Outgassing of Foam Insulation

Relationship between thermal performance of foam insulation and time degradation

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.

Polyurethane Foam R-Value Loss Mechanisms

Question: need accurate information about out gassing in foam building insulation

Thank you for an excellent article on building insulation materials (Solar Age, "Building it Right", 11/83)

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

Expert's reply:

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

From 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 in
  
  sulating 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
  
  also see CELLULOSE LOOSE FILL INSULATION
  
  and UREA FORMALDEHYDE FOAM INSULATION, UFFI)
  
  
• 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 POLYURETHANE FIRE SAFETY BULLETIN [PDF] from the polyurethanes industry

 

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

• URETHANKE OUTGASSING [PDF] Q&A article, Solar Age, April 1984 - PDF version, Use your browser's back button to return to this page

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Continue reading at FOAM SPRAY INSULATION TYPES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• CRAWL SPACE INSULATION RETROFIT
• FOAM SPRAY INSULATION TYPES - 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.
• FORMALDEHYDE HAZARDS
• INSULATION INSPECTION & IMPROVEMENT
• UREA FORMALDEHYDE FOAM INSULATION, UFFI - example of an earlier set of problems with UFFI.

Suggested citation for this web page

URETHANE FOAM INSULATION at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING INSULATION

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Citations & References

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