Both closed- and open-cell spray foams are used widely to improve the thermal performance of existing homes. Installed properly, it’s hard to beat spray foam’s contribution to air tightness and R-value. But we need to keep our eyes on three important issues: quality installation, worker protection during installation, and safe re-entry times.
How spray foams work
Spray foams all involve a two-component chemical reaction with a “Side A”—primarily containing isocyanates—and “Side B”—primarily containing polyols and a blowing agent). There are three types of spray foam and all involve some level of toxic ingredients, reactivity and curing, and therefore all require quality installation, worker protection, and safe re-entry time.
It’s critical to get the mix and mixing process just right to get the best performance from the spray foam and to limit or eliminate the possibility of un-reacted components. Make sure that your spray foam contractor is employing a quality control program, such as the Spray Foam Quality Control – Canadian Installation Requirements or the ABAA Quality Assurance program.
Whether you are installing spray foam as a part of your general contracting work, you are a full-time spray foam installer, or a do-it-yourselfer, you need to follow worker protection protocols. Repeated or long-term or acute initial exposure to unreacted components or off-gassing during uneventful correct installation of spray foams must be avoided.
Safe re-entry times
This is the toughest part of using spray foam—knowing when to recommend your clients can get back into their home or work space. First, no one should anywhere near the area of spray foam installation without protective gear. And we simply don’t know, exactly, what the safe re-entry times should be for various types of spray foams and different occupant situations (such as schools with more vulnerable children). Some manufacturers are recommending 24 – 72 hours before re-entry for two-part foams and 8 – 24 hours for one-component spray foam. But clearly more research is needed to better understand the best approach for site-applied spray foam installations. Consider both the EPA information on safe re-entry and information from Spray Foam Health and Safety.
While industry works on new spray foam formulations that are less problematic than current technology, apply current best practices for worker protection, installation quality, and safe re-entry.