Which construction type is defined by using noncombustible materials for all major structural members?

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

Answer: (B)

The key idea here is how construction types describe the materials and fire performance of the structural frame. In fire-resistive construction, the major structural members are noncombustible and are protected to achieve specific fire-resistance ratings. This combination—noncombustible structural members plus fireproofing that provides a defined level of fire resistance—defines a highly fire-resistant building. That focus on achieving prescribed fire resistance through protection, not just using noncombustible materials, is why this option fits best.

Noncombustible construction also uses noncombustible materials for the main frame, but it doesn’t mandate the same level of fire resistance as the fire-resistive type. Ordinary construction types may have exterior walls that are noncombustible while interior elements can be combustible, or they don’t require the same fire-rating targets. Other types, like those that use wood for major structural members (heavy timber) or mix combustibles inside, are defined by different material or structural characteristics that don’t center on high fire resistance of all major structural members.

So, the choice reflects a construction approach where noncombustible materials are used for the main structural members and the system is designed to withstand fire for a defined period through protective fire-resistive assemblies.