What best defines a compartment fire?

• A. A fire that spreads quickly between rooms and floors
• B. A fire outside a building caused by wind
• C. A fire confined within a room or space
• D. A fire that is extinguished by removing heat only

Answer: (C)

A compartment fire is defined by its confinement to a single room or defined space, with the surrounding structure—such as walls, doors, and ceilings—restricting the fire’s spread. The heat, flames, and smoke stay largely within that space, at least until ventilation changes or openings allow growth into adjacent areas. This containment creates specific hazards like a rapid rise in temperature inside the room and a hot gas layer near the ceiling, which can lead to dangerous conditions if air is added by opening a door or vent. Understanding this helps firefighters plan tactics to protect occupants and control ventilation while cooling the space to prevent flashover. The other descriptions describe fires that spread beyond the confined space, occur outside the building, or refer to a method of extinguishment rather than the defining confinement of the fire.