A spray polyurethane foam using a next-generation blowing agent that lowers the foam’s greenhouse gas emissions has been named the “best green building product” at this year’s International Builders’ Show.
An announcement from the National Association of Home Builders, which sponsors the annual industry gathering, named a total of 10 products in its Best of IBS Awards. They included Andersen Windows (best in show), solar shingles from RGS Energy, a wi-fi enabled circuit breaker from Leviton, and a “combi furnace” from NTI that provides space heating and domestic hot water.
Demilec’s closed-cell Heatlok HFO spray foam uses a hydrofluoroolefin (HFO) compound as the blowing agent — the part of the mix that produces insulating bubbles in the cured foam. HFOs have a drastically lower global warming potential than the hydrofluorocarbon blowing agents they replace.
In addition, Demilec says, Heatlok High Lift has an R-value of 7.5 per inch and can be sprayed in a 6 1/2-inch lift in a single pass, about three times thicker than closed-cell foam is typically applied. At least some of the oil in the “B” side of the formulation is soya oil rather than a petroleum-based oil.
A second version of the foam, called Heatlok HFO Pro, was developed for the commercial market. Demilec says it has an R-value of 7.4 per inch and creates a Class II vapor retarder and an air and water barrier in a layer 1 inch thick.
The industry is moving toward HFOs
Demilec is one of several companies that have switched to an HFO in an industry-wide transition that will take place over the next year or two, says Rick Duncan, the technical director for the Spray Polyurethane Foam Alliance, an industry trade group.
HFOs have a Global Warming Potential of about 1 (comparable to carbon dioxide), compared with the 900 to 1000 of HFC blowing agents, Duncan said. Because blowing agents makes up between 5% and 10% of spray foam, the GWP of foam made with an HFO is actually about one-eighth that of HFC-blown foam.
The blowing agent used in Demilec’s foam is a Honeywell product called Solstice. Chemours also makes an HFO blowing agent.
The industry had been preparing for a government ordered ban on HFC blowing agents in foam insulation, but a ruling by a federal appeals court in 2017 struck down the regulation. Even so, manufacturers that had been in the process of developing new HFO formulations continued to work on them. At least 10 states are planning to stick with the 2020 HFC ban despite the federal court rulin, Duncan said.
“We expect to see HFCs banned at the state level in 2020,” he said.
The switch to HFO also has significant practical advantages on the job site. Closed-cell foam is usually applied in lifts of about 2 inches, Duncan said, because thicker applications generate too much heat. At 4 inches, foam may show some internal charring, and beyond 5 or 6 inches, the foam can self-ignite. In a worst-case scenario, the foam catches on fire and burns down the house where it’s being applied.
When an applicator can apply a single layer of 6 1/2 inches, the foam hits R-49, enough to satisfy code requirements for attics in all U.S. climate zones. That feature should reduce installation time by a factor of three, Duncan said.
The Spray Polyurethane Foam Alliance announced the publication of an Environmental Product Declaration for HFO-blown foam last November. The document contains details about the product and helps contractors win credits in green building certification programs such as LEED.
Get building science and energy efficiency advice, plus special offers, in your inbox.