Which construction feature presents a higher risk during a fire and requires careful consideration?

• A. Masonry walls with no voids
• B. Concrete block walls
• C. Wood frame with heavy voids and truss systems
• D. Steel frame with minimal fire protection

Answer: (C)

Fire behavior and structural stability in different construction types is what this item highlights. A wood-frame building with heavy voids and truss systems creates hidden channels for heat, flames, and smoke to spread rapidly, often unseen from the outside. Wood is combustible, and exposed or undersupported truss members can fail quickly when heated, potentially leading to sudden collapse. That combination makes interior operations especially dangerous and demands careful planning, including assessing collapse risk, choosing ventilation wisely, and maintaining clear escape paths. By contrast, masonry walls with no voids and concrete block walls provide sturdier fire resistance with fewer concealed routes for fire to travel. A steel frame with minimal fire protection is also a hazard, since steel strength drops with heat, but its danger relies on whether adequate fireproofing is present. The most concerning scenario here is the wood-frame construction with heavy voids and truss systems because of the rapid, concealed fire spread and higher collapse risk.