Why are concrete and masonry considered to have good fire resistance?

• A. They weigh a lot.
• B. They are natural fire-resistant materials.
• C. They are painted with fireproof paint.
• D. They require ventilation.

Answer: (B)

The key idea is that concrete and masonry are mineral, noncombustible materials. Because they don’t burn or fuel a fire, they don’t contribute to flame spread and can maintain their strength and stiffness when exposed to high temperatures. This inherent noncombustible nature means they act as a barrier to heat and flames and can help hold the structure together during a fire for a period of time, which is why they’re regarded as having good fire resistance.

Weight isn’t the defining factor, and painting with fireproof paint isn’t what gives them their fire resistance—it’s their mineral composition and nonflammable characteristics. Ventilation requirements aren’t related to a material’s ability to resist fire either.