All structural members and components used in Type I construction must be made of what?

• A. Wood
• B. Non-combustible Materials
• C. Steel
• D. Concrete

Answer: (B)

Type I construction is designed for maximum fire resistance, so every structural member and component must be noncombustible. Noncombustible means the material won’t ignite or contribute fuel to a fire; typical examples are concrete, steel, and masonry. Wood is combustible, which is why it isn’t used for structural framing in Type I buildings. Steel can lose strength when heated, but Type I relies on fireproofing and protective assemblies to maintain capacity, often with concrete or other noncombustible systems surrounding the members. In short, the requirement is that all structural elements and their assemblies be made from noncombustible materials.