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Re: GBlist: ureathane foam

>I'm not sure exactly the form of spray foam your are referring to,
>traditionally concerns with polyurethane foams have been with expanding
>or blowing agents and their contributions to ozone deplition. I think
>Icynene (sp.?) is a non cfc or hcfc foam but as far as I know they all
>contain isocyanates, among other things, for which their is some info.
>John Salmen
A few more comments on polyurethane:

Most closed-cell polyurethane today (typically 2 pound per cubic foot) is
blown with HCFC-141b. This is much better environmentally than the CFC-11
that was used until a few years ago. But HCFC-141b is the worst of the
HCFCs from an ozone-depletion standpoint and is currently scheduled to be
phased out by the year 2003. Only one manufacturer that I know of, Foam
Tech in North Thetford, Vermont (802/333-4333), uses a totally
non-ozone-depleting blowing agent (an HFC) for closed-cell polyurethane.
They call this foam "Super Green" and it costs somewhat more than their
standard product.

Open-cell polyurethane foam for building applications is currently produced
by two or three manufacturers, including the Canadian companies Icynene and
Demilec. These have zero ozone-depletion effect, because they are blown
using water (which produces carbon dioxide as the foaming gas). Because the
CO2 leaks out of the open cells and it replaced with air, this type of
insulation doesn't insulate as well as closed-cell polyurethane with a
low-conductivity HCFC gas in the cells. The R-value of open-cell
polyurethane is R-3.6 to R-4 per inch.

With any polyurethane foam, however, pay careful attention to safety during
installation (see the information John provided with his posting). Both
Icynene and Demilec require installers to use full SUPPLIED-AIR breathing
equipment during installation. Isocyanates are very toxic, as readers of
this discussion group may recall in the thread on MDI resins used in
"formaldehyde-free" particleboard (the chemistry is very similar).

-Alex Wilson
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