Which condition makes Type II buildings more prone to collapse under fire?

• A. The steel components have a lower fire-resistance rating than a Type I building
• B. They are constructed of lighter-weight materials with lower-fire resistance ratings
• C. Metal roof decks are more likely to fail than laminated wood roof decks
• D. Void spaces inside the roof and truss system are less protected than in Type I

Answer: (B)

The risk comes from the structure itself being built with lighter-weight components that have lower fire resistance. Type II construction uses lighter framing and assemblies, which reach critical temperatures and lose strength more quickly under fire than the heavier, better-protected members found in Type I buildings. When fire heats these lighter elements, they can yield or fail sooner, reducing the building’s ability to carry loads and increasing the chance of collapse as the fire grows. While other factors like deck type or protected voids can influence behavior, the fundamental reason Type II buildings are more prone to collapse is the combination of lighter-weight materials and lower fire resistance in their structural members.