Question

for a building material to be considered noncombustible, it must meet the requirements in the chart.

1. no part of the material will ignite and burn when subjected to fire.
2. the material has a surfacing material under 3.2 mm thick and a flame spread index of 50 or less.

the table lists four building materials as well as the flame spread index and surfacing material
thickness of each material.
in an area at high risk for wildfires, which material should be used in construction?
a cedar
b gypsum
c spruce
d textured fiber - cement

Explanation:

To be non - combustible, a material must meet two criteria: no part ignites when subjected to fire (not directly checked in the table but we assume all are checked for this basic non - ignition as per the problem's setup for the flame spread and thickness check), a surfacing material under 3.2 mm thick, and a flame spread index of 50 or less.

• Cedar: Flame spread index is 69 > 50.
• Gypsum: Surfacing material thickness is 0.3 mm (meets < 3.2 mm) and flame spread index is 15 ≤ 50.
• Textured fiber - cement: Surfacing material thickness is 3.8 mm > 3.2 mm.
• Spruce: Flame spread index is 55 > 50.

Answer:

B. gypsum