When smoke is present in the stair core, the Smoke Detector (D) sends a signal to the Control Panel (A).
On receipt of the resultant signal from the Control Panel, the Stirling Ventilator (S) is activated, fully opening within 60 seconds.
The smoke in the stair core is then able to vent out through the highest point in the stairs, due to the natural buoyancy of the hotter air.
The Break Glass Switches (B) which are located on the ground floor and optionally at the top floor, can be used by Fire Service personnel to override the automatic controls, providing ventilation to exhaust heat, or to allow incoming replacement fresh air in response to a fire in another part of the building.