Anordning för att vid brand förhindra bakåtströmning i ventilationskanal i form av genomströmningarean täckande nät med infäst flexibel strut

摘要

A device for preventing back flow in ventilation ducts of ventilation systems and further propagation of fire and fire gases through said ventilation system. The device comprises a distance means (11) mountable in a ventilation duct (13) and covering its through flow area, at which distance means (11) a tube form (12) is attached, which has an extension is length in the direction of a flow in question and which tube form (12) comprises a flexible material and is open in its free end (15) and has a length which is sufficient when collapsing in case of back flow to cover the section area of the ventilation duct (13) for sealingly abutment against the distance means (11).