A closed door won’t stop a fire outright, but it dramatically changes how a fire behaves inside a building 🧯🧠 Fire needs oxygen, airflow, and heat to grow. When a door is shut, it restricts the flow of air into a room, which slows flame spread, limits temperature increase, and reduces how quickly toxic smoke can enter that space. This doesn’t make the room completely safe—smoke inhalation can still become dangerous over time. What it does provide is *time*: time before heat intensifies, time b