Positive pressure fans are used to supply air into the escape stairwell. They force outdoor air pressure into the indoor space. In the event of a building fire, there is a significant production of smoke and toxic gases like carbon monoxide, which can obstruct visibility. By using positive pressure fans to supply air to the fire escape stairs, it prevents smoke from reaching the stairs, creating conditions for people to escape. Positive pressure fans are typically installed on the roof of the building and are linked to the positive pressure air valves on each floor. During the early stages of a fire, the valves are opened and the positive pressure fans are activated to keep the stairwell and elevator lobby in a positive pressure state (air supply state).

Generally, louvers are installed in wind wells on each floor for use as ventilation windows. The wind wells on different floors have varying openings, with single or double-layer settings to ensure air pressure; or pressure-increasing ventilation outlets may be installed, sometimes equipped with manual and remote control devices, allowing for the adjustment of airflow.