What technique is used for cooling walls and ceilings when flashover is imminent?

The technique used for cooling walls and ceilings when flashover is imminent is referred to as an indirect attack. This method involves applying water in a way that creates steam, which effectively reduces the temperature of surfaces that may ignite, thereby preventing flashover.

During potential flashover scenarios, the temperature in a room can escalate rapidly, and the surfaces can become dangerously hot. By directing water towards the ceiling and walls from a safe distance, firefighters can cool these surfaces without directly engaging the flames initially. The steam generated provides a cooling effect and can also help reduce smoke and toxic gases, improving visibility and conditions for both firefighters and potential occupants.

In contrast, creating a fire line, using a spray nozzle, and implementing a direct attack are techniques that have different applications and levels of effectiveness for managing active flames or containing the fire spread rather than specifically targeting imminent flashover conditions.