Which types of building materials are considered fire-resistant?

Fire-resistant building materials are designed to withstand high temperatures and prevent the spread of fire. The correct answer includes concrete, steel, and fire-rated gypsum board, which are all materials known for their ability to resist combustion and decay when exposed to fire.

Concrete is a non-combustible material, meaning it does not ignite or burn, making it an excellent choice for structural elements that need to maintain their integrity during a fire. Steel, while it can lose structural strength at high temperatures, is often treated with fire-resistive coatings that help it withstand fire until the fire is extinguished or the code-required duration elapses. Fire-rated gypsum board is specifically designed for use in fire-resistive construction assemblies; it contains moisture that helps prevent it from igniting and can provide a barrier to fire spread.

The other materials listed in the incorrect options are not predominantly fire-resistant. Wood, for example, is highly combustible, and while drywall does provide some degree of fire resistance, it is not as effective as fire-rated gypsum board intended for this specific purpose. Plastic and aluminum, though they have some industrial applications, are typically not recognized for their fire-resistant properties. Lastly, although bricks and stones are fire-resistant, fiberboard can be susceptible to fire unless