Global Warming Potential - What is it and why is it important in construction?
You may have heard the term Global Warming Potential when researching and understanding various spray foam insulation products. But what does it mean and how important is it in your current and upcoming commercial (and even residential) construction projects? Over the next few blog updates, our Building Genius team takes a look at Global Warming Potential and why you should think about it if you're aiming to design or build a green project.
What is Global Warming Potential and why is it important?
A major part of the innovation of spray foam products over the last 25 years has been the evolution of blowing agents. Blowing agents are the gases used to expand the cells of foam plastic and give it additional insulating properties. Unfortunately, over time, blowing agents will migrate out of the cells and ultimately end up in the atmosphere. Closed cell foams typically use synthetic compounds as blowing agents because:
- they offer improved insulation performance
- their longer molecular structure migrates out of cell more slowly
- the closed structure of closed cell foam restricts gas loss best
Environmental critics point to two issues that blowing agent gases can contribute to—ozone depletion and climate change—as reasons for considering their use more closely. Early blowing agents such as CFC’s and HCFC’s had a high Ozone Depletion Potential (ODP) and there was a great concern that their use was causing a widening hole in the earth’s protective Ozone Layer. Today’s blowing agents have an ODP of zero, but the progress has been slower on the climate change issue.
Global Warming Potential Defined
Global Warming Potential is a measure of how much a given mass of a gas contributes to global warming over a given period of time compared to the same mass of Carbon Dioxide. By definition, Carbon Dioxide has a GWP of 1.
When CFC’s were the blowing agents in common use, blowing agents typically had a GWP in the range of 5,000, meaning they were 5,000 times more powerful agents of climate change than Carbon Dioxide. Today’s third generation blowing agents, HFC-245fa and HFC-365mfc, have a GWP of 700 to 1000. It’s significantly better than the original blowing agents that were in common use years ago but the progress is not as significant as it was on Ozone Depletion issue.
The so-called “fourth generation” blowing agents have GWP’s in the range of 5 to 15. They are not in common usage yet, so it is unclear which ones will prove most popular. What is clear is that the focus on innovation in this area is very important to the manufacturers of foam products.
We continue our look into Global Warming Potential (GWP) and how important it is in coming blog posts. Be sure to subscribe to Icynene's Building Genius blog for the latest updates!