The stack effect in a building primarily describes what?

The stack effect in a building primarily refers to the natural movement of air, driven by temperature differences between the inside and outside of the structure. When the air inside a building is warmer than the air outside, it becomes less dense and rises, creating a flow where cooler air enters at lower levels to replace it. This phenomenon is essential for firefighters to understand, as it can significantly influence fire dynamics, smoke behavior, and overall building ventilation during an incident.

Understanding the stack effect allows firefighters to predict how smoke and heat will travel within a building, which can assist in making informed decisions about ventilation strategies, firefighter entry points, and overall safety during a fire situation.