Tuesday, September 16, 2008

Do structural insulated panels really contain formaldehyde? Should you be concerned about using them in your new green home?

Yes – and no. Read on.

Formaldehyde is a common chemical and a by-product of combustion (tobacco smoke, vehicle exhaust, and fumes from fireplaces, furnaces, and wood stoves). It can also be found in water solutions such as preservatives or disinfectants, and is used in the manufacture of many building materials. Formaldehyde gas has no color, but in high quantities has a sharp smell and can be toxic.

There are two main types of formaldehyde: urea and phenol. The majority of health problems come from urea formaldehyde. In the 1950’s urea-formaldehyde foam insulation (UFFI) was developed. UFFI was usually mixed on site during a home’s construction and then injected into the walls where it could “cure” and become an insulator. Because excessive amounts of urea formaldehyde gas escaped from the walls and made people sick, UFFI has not been used since the 1980’s and is banned in many places. However, today urea formaldehyde is also present in water-resistant adhesives and is generally used in building products such as paneling and particle board in cabinets, furniture, and shelves.

Phenol formaldehyde is far less toxic than urea formaldehyde and in building applications is used as an adhesive in plywood, particleboard, and waferboard – the OSB used in structural insulated panels.
The U.S. Department of Housing and Urban Development (HUD) has acceptable limit standards for formaldehyde levels in manufactured housing – 0.2ppm in plywood products and 0.3 ppm in particle board products. The oriented strand board (OSB) used in structural insulated panels contains only small amounts of phenol formaldehyde (less than 0.1 ppm). Outdoor air levels are often higher than 0.05ppm and in urban areas can exceed 0.1ppm and because of the trace amount in SIPs, HUD has made them exempt from testing and certification.

This is why the SIPA (Structural Insulated Panel Association) answered the question, “Do SIPs contain formaldehyde?” with, “technically yes, realistically no”.

A technical report prepared by the Engineered Wood Association was prepared after extensive tests (soon after the products were manufactured and again after they had aged several months) on samples of Douglas fir, Southern pine plywood, waferboard, oriented strand board, composite panels, and a phenolic particleboard. The report draws the same conclusion, stating: “In summary, all available scientific data indicate that the maximum formaldehyde levels associated with phenolic resin-bonded wood panel products, even when freshly manufactured, are about the same as background levels present in outdoor air in urban environments. There does not appear to be any evidence that such low levels are causing health problems.” For the test analysis, read the full report titled “Structural Wood Panels and Formaldehyde”.

In conclusion, worse contributors of formaldehyde in the home can include furniture and wood finishing products, carpets, gas stoves, and kerosene heaters; therefore, it is extremely important to have proper ventilation by installing an air-to-air exchanger in your new green home. Click on the link to read more about the importance of proper ventilation in SIPs.


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