What type of attack is most efficient on a ventilation-controlled fire?

Using an indirect attack on a ventilation-controlled fire is effective due to the specific dynamics involved in such fires. A ventilation-controlled fire occurs when the fire's growth and development are primarily limited by the amount of oxygen available, rather than the amount of combustible material.

When utilizing an indirect attack, firefighters apply water in a manner that creates steam and cools the hot gases within the fire's environment. This tactic is particularly advantageous because it reduces the temperature of the smoke and gases, which may also help to displace some of the oxygen that the fire requires to sustain itself. By effectively cooling the gases and reducing oxygen availability, the fire can be suppressed more rapidly.

This method contrasts with direct attacks, where water is applied directly to the flames. In a ventilation-controlled fire, this may not be as effective since the flames are often elevated and the bulk of the heat and flames may not be immediately accessible. The defensive attack typically focuses on protecting exposures rather than actively suppressing the fire. Supportive attack often involves positioning and preparing for engagement rather than directly attacking the fire itself.

Thus, the indirect attack is the most efficient choice for managing a ventilation-controlled fire, as it optimally addresses the unique challenges posed by the fire's conditions.