Which construction type is most susceptible to rapid collapse due to lightweight components?

• A. Type V (wood frame)
• B. Type I (fire-resistive)
• C. Type II (noncombustible)
• D. Type III (ordinary)

Answer: (A)

Lightweight structural members burn through heat quickly, losing strength fast. In wood-frame construction, the entire structure relies on combustible lumber and engineered wood components. When exposed to fire, these members soften, char, and fail in connections, causing the frame to give way abruptly and collapse earlier than more massed, noncombustible systems. Noncombustible or fire-resistive designs use steel, concrete, or masonry that resist heat longer and hold the structure together longer, reducing the chance of a rapid collapse. Type III, while it can include wood interior framing, still benefits from heavier exterior masonry and isn’t as prone to sudden failure as fully wood-frame construction. So, wood-frame construction is most susceptible to rapid collapse due to lightweight components.