Air inlet vents 10 in the form of shutters are cut from the sheet, obtained by cutting out horizontal slots and by deforming at least one of the edges of said slots, preferably the upper edge 11 which is folded outwardly to channel the combustion-supporting air towards the openings. ...
There are numerous patents for preventing the spread of fire from one room to another through an opening or gap in a floor, wall or ceiling through which penetrants (e.g. pipe, tube, conduit, duct, vent, raceway, pathway, bus duct, wire, cable) pass. Such configurations are referred to...