Which construction type presents the most hazards due to plywood or wood composite I-beams?

• A. Type II Construction
• B. Type III Construction
• C. Type IV Construction
• D. Type V Construction

Answer: (D)

Wood-frame construction (Type V) is most hazardous because every structural element is combustible, including the plywood and wood composite I-beams. That creates a large fuel load and allows flames to move quickly through concealed spaces, floors, and walls. Engineered wood members like plywood I-beams can fail suddenly under heat, leading to unexpected collapse and trapping firefighters or cutting off routes for rescue. Other types use noncombustible materials or have more mass and fire resistance, while Type V’s lightweight, fully wood structure means faster fire growth, easier ignition, and greater collapse risk, making it the most dangerous for fire attack and rescue operations.