Which construction type requires all structural members to be made from noncombustible materials?

• A. Type II
• B. Type III
• C. Type I
• D. Type IV

Answer: (D)

The key idea being tested is how construction types specify what materials can be used for the structural framework to achieve certain fire performance. When every structural member must be noncombustible, you’re looking at the fire-resistive, or noncombustible, construction approach. In that category, the structural frame is built from noncombustible materials such as concrete or steel and is designed to meet high fire-resistance ratings, with protection as needed to slow or prevent fire spread.

Heavy timber construction—often labeled as a different category—uses large wood members. Wood is inherently combustible, even though large timbers can perform well in fires due to mass and charring, they do not meet the requirement that all structural members be noncombustible. So, this type does not align with the idea of all structural members being noncombustible.

Understanding this distinction helps you see why the construction type characterized by universal noncombustible structural members is the fire-resistive/noncombustible category, not the heavy timber type.