Class C Fire Rating

Wondering what a Class C Fire rating means?  Me too. I mean, I have always known that the majority of DaVinci Roofscapes products are Class A fire rated (just a few of our lightweight roofing solutions need the appropriate underlying fire barrier to achieve the Class A assembly), but I wonder what Class C means.  So I decided to look it up for you and share what I found.

When it comes to roofing products, there are standard testing methods for fire tests of roof coverings. We often use ASTM standards.

According to ASTM's website, "1.2.3 Class C Tests are applicable to roof coverings that are effective against light test exposure, afford a light degree of fire protection to the roof deck, do not slip from position, and do not present a flying brand hazard."

The (A, B, or C) class rating given to roofing products that have been tested are named after the size of the "burning brand" that is placed on the roof during the fire test.

The Burning Brand Sizes Are:

  • Class C - 1" x 1" Burning Brand
  • Class B - 6" x 6" Burning Brand
  • Class A - 12" x 12" Burning Brand

The brand is first lit exposing each edge and face to the flame for 30 seconds.  Want to see what that looks like?  You can check them out in the video below:

To achieve the above ratings, the burning brand cannot burn through the bottom of the deck and the heat transfer cannot be enough to result in ignition on the other side of the deck. If those two things do happen then the roof covering or assembly (roof covering and underlayments) fails the test. If they fail the test, then they do not get a rating.

Do you have one of our Class A fire rated roofs?  We want to see a photo of it!  Please feel free to share your story here.

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