Open cell insulation foam is trimmed overhead.

Is Spray Foam Insulation Flammable?

Lots of people are learning about the truly extraordinary insulating capabilities of Spray-On Foam & Coatings. In fact, it seems like each year more and more people are discovering just how well spray foam insulation works to insulate buildings and reduce energy costs.

We’ve been at the forefront of this innovative technology for almost five decades. We can attest to the fact that — despite its reputation for effectiveness — some folks are still surprised to learn there’s an alternative to fiberglass insulation. Those folks quickly come to understand just how much more effective it is than fiberglass. And that’s why we say more and more people are coming aboard the spray foam insulation revolution!

Naturally, people have questions — not just about the product’s effectiveness, but about its safety. We go over a few of these questions on our FAQs page, which you can see here. You’ll notice that one of the questions concerns spray foam’s fire rating? Our answer: “Our products have a class 1 hour fire rating.”

What does this mean? And how is this tied into the question we ask in this blog post’s headline: Is spray foam insulation flammable?

Let’s cut to the chase. Yes, spray foam — like all foam plastic materials — is flammable. However (and here is where that fire rating comes in), a “class 1 hour fire rating” means that the material can resist exposure to a standardized fire for one hour. This means it can help control the spread of a fire, and in any case, will not act as an accelerant. has a good definition of this type of rating as it applies to walls within a construction.

“Fire resistance ratings are expressed in the number of minutes or hours a structure can withstand a fire simulation test,” they write. “According to the Engineered Wood Association, a one-hour rating indicates that a wall constructed in a manner similar to the one tested will contain flames and high temperatures, and support its full load, for at least one hour after the fire begins.”

Remember: This rating does not indicate that the material is fireproof — only that it has fire-resistant properties.

The International Building Code, which sets these standards, is a valuable resource.

Of course, you can always contact Spray-On Foam & Coatings with any questions or concerns. We’re happy to help!

We use both closed-cell spray foam insulation and open-cell spray foam. The materials and methods we use to install spray foam and to inject foam into your wall cavities create an impermeable membrane that hardens upon application.

Similar Posts