Patent ID: 8246703

Claim:
An air filter system for a building having a first zone and a second zone, the system comprising: a floor having a door threshold region; a wall-door system supported by the floor comprising: an air flow barrier wall separating the first zone from the second zone; an air flow barrier door frame mounted in, and substantially sealed to, the wall, the door frame having two side jambs and a head jamb; an air flow barrier door generally sized to fit within the door frame, the door having two side edges and upper and lower edges and being hinged along one side edge to a side jamb of the door frame; weatherstripping mounted between the side and upper edges of the door and the door frame and between the lower edge of the door and the threshold region of the floor, except in a pre-determined air flow permitting region, to substantially seal against air flow around the door when the door is closed except through an air flow opening defined by boundaries of the air flow permitting region; and, an air filter mounted to extend substantially across said air flow opening.