English：

In the construction of building electromechanical installations, the shafts for the installation ofair ducts in traditional mechanical pressurized air supply systems often encounter shear walls or steelstructure walls on three sides,which leads to difficulties such as loose flange bolt connections, high safetyrisks, and limited space during duct installation. A flange construction technology inside the duct isproposed,which ensures uniform tightening of flange bolts through internal operations within the duct,enhancing connection strength and tightness. At the same time, multiple platforms are used as fallprevention measures to ensure construction safety. Compared with traditional processes, this technologyeliminates the need for lifting equipment such as cranes and winches, reducing machinery rental costs andsite occupation, and effectively improving the quality and safety of duct construction.