Type 3 construction is characterized by exterior walls and structural members being noncombustible or limited; interior framing is wood. Which option best expresses this?

• A. Exterior walls and interior framing both wood
• B. Exterior walls steel, interior framing wood
• C. Exterior and interior all noncombustible
• D. Exterior walls and structural members noncombustible or limited; interior framing wood

Answer: (D)

Type III construction uses a noncombustible or limited exterior shell with a wood interior framework. This means the exterior walls and the main structural members are designed to resist fire, while the interior framing is wood, which can burn and influence fire development inside the building. The best expression of this pattern is the statement that exterior walls and structural members are noncombustible or limited, with interior framing wood, because it captures both the fire-resisting exterior/structure and the combustible interior framing. Other descriptions either place wood on the exterior, describe all components as noncombustible, or don’t specify the interior structural members, which doesn’t match Type III.