The folding door of large factory building is a special door type designed to meet the needs of industrial and commercial space. The door panel can be made of colored steel plate, stainless steel plate and aluminum plate. The frame material is stamped with hot-dip galvanized cold-formed profile, the door panel is filled with high-density flame-retardant polyurethane foam material or fireproof rock wool board, and the surface of the door panel is treated with rib stripe technology (to increase the strength and beautiful appearance of the door panel). The sealing device adopts high-quality EPDM rubber sealing or brush sealing device, and high-quality hardware fittings (special hardware, rails, hinges, etc. are matched according to the selected profile). All selected accessories shall be rustproof (galvanized, sprayed and oxidized);