Which type of ventilation involves openings in roofs or floors so that heat, smoke, and toxic gases escape the structure in a vertical direction?

Vertical ventilation is a firefighting tactic used to remove heat, smoke, and toxic gases from a structure by creating openings in the roof or upper levels. This method relies on the principle that hot gases and smoke rise due to their lower density compared to cooler air. By creating a vertical opening, firefighters allow these hazardous materials to escape, significantly improving visibility and conditions within the building for both occupants and responders.

The effectiveness of vertical ventilation is particularly enhanced in situations where the heat and smoke are trapped at the ceiling level. By venting vertically, firefighters can also lower the overall temperature within the structure, which can help control the fire and prevent it from spreading further. This method is crucial during firefighting operations, as it improves safety and efficiency while firefighting personnel are conducting interior operations.