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Does Healthy SPF Exist?
Spray Foam products marketed as being healthier may be formulated without some of the hazardous chemicals traditionally found in SPF products, but don’t replace the really bad actor chemicals.
- SPF insulation - even those with improved formulations - remain at the bottom of our Stoplight chart, in dark red.
It’s a familiar scenario: Healthy Building Network will present the HomeFree stoplight chart on insulation, which lists SPF at the bottom in dark red. Someone - usually a contractor - will raise their hand and offer something along the lines of,
“SPF works so well, and is so easy to install… what if we use the ‘green’ kind?”
Good question. SPF products marketed as being “green,” or “natural,” or otherwise improved are beginning to hit the market. And project teams may be tempted to use these products, given SPF’s reliable performance and ease of use.
But our review of these products confirms that, while these products are free of some of the traditional bad actor chemicals found in SPF foams, they still contain hazardous substances, and should be avoided whenever possible.
Here’s why. (Warning! Science ahead!)
The hazards from SPF come from two issues: 1) the fundamental limitations of polyurethane chemistry; and 2) additives that provide various performance characteristics.
Polyurethanes are made by reacting two types of substances - a polyol and an isocyanate. Exactly which polyol and which isocyanate can be variable, depending on the type of end product desired.
Some polyols based on soy or other plant derivatives are available for use in polyurethane products. While this is an important shift in the market, when used in SPF these polyols represent only a portion (we’ve see up to around 20%) of the finished foam.
Often, half or more of an SPF product is comprised of isocyanates. These substances are extremely potent asthmagens - as little as one drop could be enough to cause someone to develop asthma. These isocyanates continue to react after the SPF has hardened (there’s no agreement in the industry about exactly how long it takes to fully cure), and building occupants can be exposed.
On the additives front, some new SPF products have switched to a blowing agent that does not contribute to climate change, which is a very good thing indeed.
However, the “improved” SPF products we’ve reviewed to date still appear to incorporate chlorinated flame retardants, which have been the focus of global attention recently for their ability to impact both human health and wildlife.
For more information on the composition of SPF, see its Common Product Profile.