Understanding the GWP, ODP, and 3rd Generation Spray Foam Phase Out

In many states across the U.S. and throughout all of Canada, regulators have begun implementing requirements that phase out and prohibit the use of a group of blowing agents, hydrofluorocarbons (HFC), that are widely used in closed-cell spray foam insulation. The blowing agent in spray foam insulation is what transforms it from solid polyurethane into foam, giving the foam its structure and its R-value. As a result, it is a critical component to spray foam insulations. The relatively new regulations prohibiting the use of HFCs in spray foam insulation are designed to help reduce the use and emission of heat trapping chemicals that can contribute to climate change.

These regulations are based on the high Global Warming Potential (GWP) of HFCs. The GWP is a measurement that allows researchers to compare the impact of various gasses on the atmosphere. A gas’s GWP is established by comparing how much energy one ton of that gas will absorb to the amount of energy one ton of carbon dioxide (CO2) will absorb over a given period of time (typically 100 years)1.

Since CO2 is the reference gas, it is assigned a GWP of 1 regardless of the time period being measured. Materials with a larger GWP have a greater potential to warm the earth compared to CO2. Additionally, materials that have a longer lifetime (remain in the atmosphere longer), have the potential to have a higher GWP simply because they continue to absorb energy after other gasses may dissipate.

Scientists have determined that a gas’s effect on warming the Earth depends on three factors2:

1.     The gas’s ability to hold heat energy: Some gasses absorb more heat energy than others.

2.     The gas’s lifetime (how long it remains in the atmosphere): Some gasses only last for a decade while others can last for hundreds or even thousands of years. A long-lived gas with the ability to absorb a large amount of heat energy will contribute far more to global warming or climate change than one with a lower potential for heat absorption or a shorter life span.

3.     How much of the gas is in the atmosphere: The more of a gas in the atmosphere, the greater potential it has to trap more heat.

When we look at the HFCs used as blowing agents in 3rd generation spray foam insulations, we find that while they help provide excellent R-values and structure to the insulation, they can also have high GWPs. The HFC blowing agent used in JM’s third generation spray foam, JM Corbond® III, has a GWP between 950 and 1020. Some HFCs used by 3rd generation spray foam manufacturers throughout the industry have a GWP of 3400 or more.  As a result of these higher GWPs, even relatively small concentrations of HFCs released into the atmosphere can have a disproportionately high impact on global warming3. This is why many states in the U.S. and all of Canada have phased out or begun to phase out the use of HFCs.

As HFCs have been phased out, the fourth generation of spray foam insulation has made its way to the market. These newer spray foams are not made with an HFC blowing agent. Instead they use blowing agents with a significantly lower GWP. For example, JM’s Corbond® IV , our fourth-generation spray foam made with a hydrofluoro-olefin (HFO) blowing agent, was just released in January 2021.

This HFO blowing agent has a GWP of less than 2. More importantly, installers can still get the same performance out of JM Corbond IV that they did out of JM Corbond III despite the different blowing agents, including installing it using the immediate-pass method.

Fortunately, neither HFCs nor HFOs used in 3rd and 4th generation spray foams are considered ozone depleting substances (chemicals that damage the ozone layer that protects the Earth from the sun’s radiation). As a result, both Corbond III and Corbond IV have an Ozone Depletion Potential (ODP) of 0.

In states and countries where the HFC phase out has begun, installers can use 4th generation spray foams, and they can typically still use 3rd generation spray foams that were manufactured prior to the date specified by local regulations. In the U.S. there are many states that have not prohibited the use of HFCs, and installers located in these states can choose between using a third generation spray foam, like JM Corbond III, and fourth generation spray foam, like JM Corbond IV.

If you’re not sure whether your location has begun to phase out HFCs, visit the Spray Foam Coalition’s website, State Phase-Down of HFCs in the Polyurethanes Industry. For more information about JM’s spray foam insulations, visit our Spray Foam Product Page.


1.     https://www.epa.gov/ghgemissions/understanding-global-warming-potentials

2.     https://www.epa.gov/ghgemissions/overview-greenhouse-gases

3.     https://www.epa.gov/ghgemissions/overview-greenhouse-gases#f-gases