Which letter represents the highest fire-resistance rating for shingles?

Which letter represents the highest fire-resistance rating for shingles?

• A. B
• B. C
• C. D
• D. A

Answer: (D)

Fire-resistance ratings for shingles are shown as classes, with Class A offering the greatest resistance to fire spread. This rating comes from standardized tests that simulate a roof fire and measure how well the roofing materials resist ignition and flame propagation. Among the common ratings, Class A is higher than Class B, which is higher than Class C. The higher the class, the longer the roof assembly resists fire exposure, giving more time for occupants to evacuate and for firefighters to respond. So, the label that denotes the strongest fire performance corresponds to Class A. (Note: some test sheets label options differently, but the hierarchy remains Class A as the highest fire resistance.)

Fire-resistance ratings for shingles are shown as classes, with Class A offering the greatest resistance to fire spread. This rating comes from standardized tests that simulate a roof fire and measure how well the roofing materials resist ignition and flame propagation. Among the common ratings, Class A is higher than Class B, which is higher than Class C. The higher the class, the longer the roof assembly resists fire exposure, giving more time for occupants to evacuate and for firefighters to respond. So, the label that denotes the strongest fire performance corresponds to Class A. (Note: some test sheets label options differently, but the hierarchy remains Class A as the highest fire resistance.)