DuPont Introduces HFC-Free Spray Foam Insulation

DuPont introduced a new version of its spray polyurethane foam insulation that is HFC-free. This is a big step for the climate and a big step in building.

There are two major sources of greenhouse gas emissions in buildings that we need to reduce or eliminate if global heating is going to be kept below 1.5 C: Operating emissions that come from running a building and upfront emissions—or embodied emissions—that come from the production of the materials used in the construction of the building.

In the decades since the oil crisis of the 1970s, the industry has been focused on reducing operating emissions. Spray polyurethane foam was the most wonderful stuff for dealing with these because of its very high R-value, or resistance to heat transfer, per inch of thickness. It was incredibly useful in tight spaces like cathedral ceilings or flat roofs—I installed it in my own home under a roof deck.

However, since the Paris Accord set a carbon budget—a limit on how much greenhouse gas we can put into the atmosphere—the green building world has been looking at the upfront emissions of materials much more closely.

Spray polyurethane foam has been such an interesting contradiction: It's brilliant at dealing with operating emissions, but disastrous upfront, because the blowing agents used to make it foamy were hydrofluorocarbons (HFCs). Originally introduced to replace chemicals that were destroying the ozone layer, HFCs have global warming potential values 2,100 to 4,000 times that of carbon dioxide.

The bizarre and counterintuitive contradiction the industry is just beginning to come to grips with is that the upfront emissions of greenhouse gases from spraying the foam can actually be greater than the savings in operating emissions over the life of the building. As can be seen in the graph prepared by Chris Magwood of the Endeavor Centre, the total carbon emissions from a home insulated to high-performance standards with heat pump for heat and lots of polyurethane foam are almost three times as high as a home built to code.

The stuff is still being sold and installed because the significance of upfront and embodied carbon is not universally appreciated, but it is likely doing more harm than good. (This is not just hippies at Treehugger talking—read Catherine Paplin at Steven Winter Associates saying much the same thing.)

Fortunately, we have the Kigali Amendment to the Montreal Protocol, an agreement to phase out HFCs that has been signed by many nations and which President Joe Biden has agreed to finally ratify. DuPont is getting ahead of the deadline with its new Froth-Pak Spray Foam.

According to DuPont's statement, it contains no ozone-depleting chemicals or HFCs.

“We are committed to the transition to more sustainable buildings, while ensuring our products continue to deliver the high level of performance our customers trust and expect,” said Amy Radka, retail marketing director, DuPont Performance Building Solutions. “HFC-free Froth-Pak™ is a demonstration of our continued commitment to providing the market with products that address environmental challenges while meeting the needs of our customers. We’re committed to delivering better solutions that address climate change, drive the circular economy, deliver safer solutions and help communities thrive.”

There is not a peep in the release about upfront or embodied carbon. The industry still doesn't want to talk about it, but we will take what we can get. We do not know what the new blowing agent is, and have reached out to DuPont to find out, but have not received a response at the time of writing.

But this is still a big step in building. As the DuPont statement concludes:

"The reformulation implements our Integrated Energy Strategy to address all sources of GHG emissions, including efforts to create low-carbon industrial processes, source low-carbon and renewable energy, and reduce our overall energy use. One-hundred percent of the electricity used to make Froth-Pak™ comes from renewable energy sources. Through this continued leadership and investment in globally sustainable products using technology and innovation, we aim to build energy-efficient, resilient and durable homes in a rapidly changing world."

Is Sprayed Polyurethane Foam Back on the Menu?

There are still major problems with spray foams. As can be seen in the safety data, Tris, a controversial halogenated flame retardant, is over 20% by weight. The safety data sheet goes on for 22 pages about dangers to firefighters, chemicals used in its manufacture have issues: "Diethylene glycol has caused toxicity to the fetus and some birth defects at maternally toxic, high doses in animals." and "Contains component(s) which have been shown to interfere with reproduction in animal studies." No wonder my colleague Margaret Badore asked a few years ago: How can the toxic chemicals in spray polyurethane foam be considered green?

Shredded newspaper, or cellulose insulation, seems a lot more benign. But there are many places where spray foam insulation is really useful and effective, if it is installed properly hidden behind drywall it is generally considered safe. It is so useful in tight spaces and in sealing around windows or filling gaps that that getting rid of HFCs has to be considered a very big step in building.