In Type 3 construction, which element is described as noncombustible or limited combustible?

• A. Exterior walls
• B. Interior structural members including walls, columns, beams, floors, and roofs are wood
• C. Exterior walls and interior structural members are noncombustible
• D. Roofs are steel

Answer: (B)

In Type 3 construction, the exterior walls are the noncombustible element. The exterior envelope is built with noncombustible materials to resist fire spread from the outside, while the interior framing is typically wood, which is combustible. So the feature described as noncombustible or limited combustible is the exterior walls. The interior structural members—walls, columns, beams, floors, and roofs—are usually wood in this type, which is why they are not described as noncombustible. Roof materials can vary and aren’t universally noncombustible.