Air & Water Tight
Why a service opening is a pressure boundary
In a clean room or an operating room, a service opening is a pressure boundary. Air moving through the gap around an ordinary access panel undoes the room's pressure regime, and in a wash-down area water finds the same gap. An air and water tight door closes both paths.
KAWT construction, finish and standard sizes
Karp builds one model for this application. The KAWT is 16 gauge steel construction with a 5 stage iron phosphate coating and a white baked, paintable enamel finish, so it can be finished to match the surrounding wall without compromising the coating underneath.
It is specified for installation in walls and ceilings where prevention of both air infiltration and water penetration is required. Karp names the intended environments directly: clean rooms, hospitals, laboratories, operating rooms and pharmaceutical buildings, and any location where an airtight and watertight seal is required.
Standard sizes are 8 x 8, 12 x 12, 14 x 14, 16 x 16, 18 x 18, 24 x 24, 30 x 30, 36 x 24, 48 x 30 and 48 x 36 inches. Most sizes carry two stud catches. The two largest, 48 x 30 and 48 x 36, carry five, which is what holds a large panel evenly against its seal across the full perimeter.
Latch count and frame flatness decide the seal
Latch count and frame flatness. A door with enough latches and a true frame seals; a door pulled tight at two points across a 48 inch span does not, which is why the large sizes carry five. Confirm the opening is framed square and that the frame is not distorted during installation.
Where the same opening also needs a fire rating, specify from the fire rated category and confirm the listing, rather than assuming the gasketed door carries a rating.