What is the neutral plane?

The neutral plane is defined as the height at which the pressure differences between the hot gases produced by a fire and the cooler air in a compartment are equal. This means that at this specific level, there is no net movement of air in or out of the compartment; the pressure is balanced. Below this plane, cooler air tends to flow into the compartment as it is denser, while above it, the hot gas and smoke will flow out due to being less dense. Understanding the neutral plane is crucial for firefighting tactics, as it can influence the behavior of smoke and heat, and inform the safest entry and exit points during firefighting operations. Firefighters use knowledge of the neutral plane to avoid smoke inhalation and ensure effective ventilation strategies.