Lightweight trusses and engineered floor systems can fail in _________.

• A. Seconds
• B. Minutes
• C. Hours
• D. Days

Answer: (B)

Lightweight trusses and engineered floor systems are thin, high-strength members that can lose stability quickly when exposed to heat. In a fire, rapid heating degrades the strength of wood components and the adhesives or fasteners that hold engineered members together, causing stiffness and load-carrying capacity to drop faster than heavier construction. Because these systems are light and often support significant loads through slender connections, they can reach a critical point and fail in a relatively short time—typically within minutes—rather than minutes turning into hours or days. This rapid potential collapse is why the correct timeframe is minutes.