Define "horizontal ventilation" in a firefighting context.

Horizontal ventilation refers to the process by which smoke, heat, and toxic gases are removed from a structure horizontally, typically through windows or doors. This technique plays a crucial role in enhancing visibility and reducing the risk of flashover during firefighting operations. By effectively clearing the smoke and heat away from both the fire area and the escape paths for occupants and firefighters, horizontal ventilation improves the overall safety and effectiveness of the firefighting effort.

This method is particularly useful in single-story structures or in situations where fire conditions allow for safe access from the exterior. It's important to note that horizontal ventilation should be coordinated with the attack on the fire to prevent allowing more oxygen into the structure, which could potentially intensify the fire.

The other options do not accurately describe horizontal ventilation. Sealing windows and doors is typically associated with defensive tactics or minimizing exposure, while high-pressure hoses are a method used for fire suppression rather than ventilation. Cooling the building's exterior, although important in firefighting, does not directly relate to the process of removing smoke and heat from within a structure.