For Architects

Wood Fiber Acoustical Panels with a Flame-Spread of Zero

Each and every Cardinal Acoustic wood fiber product comes with a Class A fire rating and boasts an impressive perfect 0.0 flame-spread result. This classification is important but often overlooked when selecting acoustical materials for a project. Here’s more information on the process by which our acoustical panels have gained a Class A fire safety rating and what that rating means for the construction materials used in a project.

Understanding Fire Ratings for Building Materials

The National Fire Protection Association (NFPA) determines US standards and codes for fire prevention. After testing every construction material, the NFPA assigns a flame-spread rating.

Our wood fiber acoustical panels undergo the ASTM E84-18 (“tunnel test”). For this test, the NFPA hangs our acoustical panels in a long room that’s ten feet wide, ten feet high, and thirty feet long, and allow a fire to burn in the room for ten minutes. The acoustical panels are then tested to see whether they emitted smoke or burned during the fire. The Class A rating is awarded to panels with a flame spread of 0 to 25 and smoke development of less than or equal to 450. (Class B has a flame spread of 26 to 75; the Class C range is 76 to 200; the smoke-development numbers are the same.)

Why Don’t Our Wood Fiber Acoustical Panels Burn?

Cardinal Acoustics’ panels don’t just fit into the 0-25 flame-spread rating, they score a perfect flame-spread result of 0. While most wood products fall into Class C range, our panels use a special bonding agent that not only seals together the various wood fibers but also protects those fibers from burning. Although panel discoloration was observed less than two minutes in, our panels resisted catching fire for the duration of the test.

Additional Testing for Acoustical Panels

The Canadian NFPA does not accept US fire-test results and, before they award certification, they require three separate tests—which is more expensive for the manufacturer but ensures that no unusual factors skew a single test result. Yet, even after the three phases of testing, our panels passed the Canadian NFPA certification.

Some groups advocate for hour-long fire tests, but we’ve never seen a successful one. One-inch acoustical panels are heavy, and in a longer fire test, the lay-in grid system which suspends the panels heats and the metal curls, causing the panels to fall to the floor before the test ends.

If you want to increase fire resistance in your building, we recommend installing double drywall, which can provide a one-hour fire rating, before installing our wood fiber acoustical panels to ensure a more fire-resistant building.

If safety is a priority for your next construction project, contact us for a more detailed report on our Class A rating. Call us at 614.721.3001, email us at, or fill out our brief online form.