has been designated in writing by the person in charge of the installation in which the room is situated as being a room in which smoking is permitted;

has a ceiling and, except for doors and windows, is completely enclosed on all sides by solid, floor-to-ceiling walls;

does not have a ventilation system that ventilates into any other part of the premises (except any other designated rooms);

does not have any door that opens onto smoke-free premises which is not mechanically closed immediately after use; and

is clearly marked as a room in which smoking is permitted.