A duct element (1) for an air flow or for a gas flow and a method for manufacturing, handling and mounting the duct element (1). The novel duct will replace ducts of steel and thus have enough restraint towards flexure to be hung without any substantial flexure in connection to a mounting procedure. The advantages are a substantial reduction in price per meter of duct installed, and it makes manufacturing, handling and mounting easier as well as transportation and storing as the duct (1) can be folded or rolled in a flattened and space saving condition. The duct (1) can be bent in a mounted position, i.e. be allowed to be changed in direction having a minimum radius of about 1000 mm.