What does "thermal layering" refer to?

Thermal layering describes the phenomenon where gases in a fire environment stratify or form distinct layers based on their temperature. In a fire situation, as heat rises, the temperature of the gases increases, creating a stratification effect where hotter gases rise to the top while cooler gases remain lower. This layering can significantly impact firefighting strategies and safety, as firefighters need to be aware of the heat and smoke layering to avoid the dangers associated with high-temperature zones. Understanding thermal layering is essential for anticipating how smoke and heat will travel within a structure during a fire, and it informs the decision-making process regarding ventilation and entry tactics in firefighting operations.