Stairwell ventilation can be achieved by automatically opening a window within the stairwell. As always this is subject to the minimum free area being achieved when calculated using the method in diagram C7 of Approved Document B.
It is recommended that bottom hinged outward opening windows are selected for efficient smoke evacuation, however this is not a requirement of ADB. Stairwell ventilators are more commonly used for replacing fresh air in a lobby extract system.
A variety of actuators are available for different window types depending on what the required free area is.