Why should fire doors be kept closed during a fire?

• A. To compartmentalize fire and smoke, slow spread, and preserve tenable conditions of other spaces.
• B. To prevent any fire from ever entering other rooms.
• C. To keep heat and smoke in the engine room only.
• D. To block firefighter access entirely.

Answer: (B)

Keeping fire doors closed helps create fire compartments. When a door stays shut, flames, heat, and smoke are slowed from moving into adjacent spaces. That containment buys time—the space remains tenable longer, making it safer for occupants to evacuate and giving firefighters better conditions to operate. It’s not a guarantee that fire won’t reach other rooms, but the delay in spread is the crucial safety benefit. The idea that heat and smoke stay only in one place or that doors should block access for responders doesn’t reflect how fire doors are used in real buildings; their purpose is to slow spread and protect more areas, not to trap people or prevent firefighting.