Which building type will present a greater potential for collapse?

Which building type will present a greater potential for collapse?

• A. Heavy-timber construction, Type IV
• B. Fire resistive construction, Type I
• C. Lightweight wood-frame construction, Type V
• D. Masonry construction, Type III

Answer: (C)

Under fire, how a building is built largely determines how quickly its structural system can fail. Lightweight wood-frame construction uses thin, combustible members (studs, joists, sheathing) with limited redundancy, so heat quickly weakens connections and load paths. As fire erodes the framing, floors and roofs can give way and the building can collapse faster than heavier, more fire-resistant systems. Heavy-timber construction uses large timber members that char on the surface and retain strength longer, providing more time before failure. Fire-resistive construction employs protective assemblies that withstand heat for a designed period, helping preserve structural integrity. Masonry construction relies on noncombustible walls, which can remain standing even if interior elements burn, though internal components can still fail under sustained fire. Overall, the lightweight wood-frame system presents the greatest potential for collapse due to its combustibility and lower redundancy.

Under fire, how a building is built largely determines how quickly its structural system can fail. Lightweight wood-frame construction uses thin, combustible members (studs, joists, sheathing) with limited redundancy, so heat quickly weakens connections and load paths. As fire erodes the framing, floors and roofs can give way and the building can collapse faster than heavier, more fire-resistant systems.

Heavy-timber construction uses large timber members that char on the surface and retain strength longer, providing more time before failure. Fire-resistive construction employs protective assemblies that withstand heat for a designed period, helping preserve structural integrity. Masonry construction relies on noncombustible walls, which can remain standing even if interior elements burn, though internal components can still fail under sustained fire. Overall, the lightweight wood-frame system presents the greatest potential for collapse due to its combustibility and lower redundancy.