Patent ID: 7597129

Claim:
A door structure, said door structure comprising a door selectively movable between open and closed conditions; a frame formed from spaced side members; and a top member which, in combination with the floor, define the opening in which the door is positioned, the door when closed, formed by a first wall forming an external surface at a first side of the opening and a second, spaced wall defining an external surface to the second side of the opening, said first and second walls defining a cavity between the same which extends substantially across the area of the opening and air movement means are provided to cause the movement of air into and through the said cavity and wherein the air is introduced into the cavity from a port located on one of the side members of the door frame and towards the lower edge of the door when the door is closed, wherein the lower edges of the first and second walls are joined by a plate, and wherein a perforated layer of material is provided adjacent the lower edge of the door, said layer and plate forming a channel into which air passes from the side member ports and then passes through the perforated layer apertures.