Manufacturers of rigid foam insulation board have successfully phased out the ozone-destroying chlorofluorocarbons (CFCs) once used as blowing agents, replacing them with hydro-chlorofluorocarbons (HCFCs). But the HCFCs aren't 100 percent ozone-friendly, either, and the government plans to phase them out, too. The foam industry says that replacing HCFCs in rigid foam panels could prove difficult.

In the meantime, there are already some ozone-safe foams for spray-on or injection applications. The Icynene Insulation System, formerly called Insealation, has been around for several years. It's a spray-in-place, modified urethane, containing no formaldehyde, CFCs or HCFCs. It expands 100-to-1 as it's installed, provides an in-place R-value of around 3.6, and creates an air barrier as well as insulating.

The latest ozone-friendly arrival is Supergreen, introduced in 1993 by Foam-Tech Inc. of North Thetford, Vermont. Supergreen uses a hydro-fluorocarbon HFC-134a as a blowing agent. HFCs contain no chlorine and have no effect on the ozone layer. Estimates of Supergreen's long-term R-value range from 6.0 to 7.6 per in. It's available as either a urethane or a polyisocyanurate foam. Like Icynene, Supergreen expands to fill spaces and seal cracks, making it ideal for hard-to-reach framing cavities. It also acts as an air barrier and vapor retarder.

R-value for R-value, injected foam is an expensive choice. How expensive depends on the job. But Foam-Tech President Henri Fennell insists that injected foam is cost-competitive even for walls in new construction. For Supergreen, the high cost per R is offset by a higher R-value per in. This, he claims, lets the builder frame with 2x4s instead of 2x6s. And by using the injected foam, says Fennell, the builder can eliminate housewrap and poly vapor retarders.

Not all builders are so sure of using injected foam for insulating new walls. At least one Vermont-based contractor ran the numbers and found he could get the R-values he wanted for less money with fiberglass. He recommends the foam for retrofits, but cautions that cleanup is a concern. "It's sloppy," he says. "I wouldn't bring it into someone's living room."

Contact:
Icynene Inc. and Foam-Tech, Inc.

--Adatped from the Journal of Light Construction.