Fire Department Incident Safety Officer Practice Test

Why are Type V buildings considered vulnerable during a fire?

1. High thermal resistance

2. Excessive occupancy load

3. Combustible construction materials

4. Low building height

The correct answer is: Combustible construction materials

Type V buildings are considered vulnerable during a fire primarily due to their use of combustible construction materials. This category includes buildings that are built entirely of wood or other non-fire-resistive materials, making them more susceptible to ignition and rapid fire spread. The materials used in Type V construction, such as wood framing and plywood sheathing, can ignite easily and burn quickly, resulting in a rapid deterioration of structural integrity. As a fire develops in a Type V building, the flames can spread throughout the structure with little resistance, increasing the risk of flashover and compromising the safety of occupants and firefighters. In contrast, buildings constructed with non-combustible materials—such as steel or concrete—typically have better fire resistance, slow the spread of flames, and provide more time for evacuation and firefighting efforts. Thus, the combustible nature of materials in Type V construction is a critical factor in their vulnerability during a fire incident.