Abstract: An elongated channel-shaped structure, preferably of anodized extruded aluminium, is suitable to form the load bearing beam of a false ceiling assembly, in particular comprising absolute filters for the so-called "clean rooms". Such a structure is U-shaped and comprises an elongated and uninterrupted central slot or groove for the fixing to the ceiling, with the concavity of the U-shape directed downward, having outer lateral finnings for the cooling, outer grooves and projections for the coupling with transverse spacers and for supporting absolute filters, as well as inner grooves and projections for supporting electric lines, pipes and other devices and systems. There are also provided extension members directed downward, to be fastened to said structure and having further support and guide fit grooves.