Cold room door
Also known as: insulated door, sliding cold room door, hinged cold room door
Short definitionA special door with an insulated leaf, gaskets all round and, in freezer rooms, a heated frame. Hinged, sliding, swing and high-speed types are chosen by traffic and room temperature.
The door is the weakest point of the room in terms of heat. When open, cold air flows out and warm, moist air flows in; when closed, the gasket and frame leak heat. The leaf is made of the same foam as the panels, 60–150 mm thick, with two or three rows of gasket around it. In a freezer room a heater cable is laid in the frame so that the gasket does not ice up and stick the leaf.
The type is chosen by traffic. A hinged door of 0.8–1.2 m is enough for small and medium rooms; a safety handle that opens from inside is mandatory. Openings of 1.5–3 m used by forklifts get a sliding door, and very busy passages a swing door or a high-speed roll-up door. The load calculation asks how often the door opens: in a busy distribution store the air entering through the door can reach one third of the total load.