Large-span Steel Fire Shutter

For large-span curtain surface, gradient plate thickness design is adopted: thicker at mid-span and thinner at both sides. Slats are interlocked and overlapped with tiny rotational clearance to ensure smooth rolling and prevent lateral dislocation. Thermal expansion gaps are reserved on slats to release thermal expansion stress under high temperature and avoid arching and buckling.

Guide rails are fixed to the building structure via densely arranged adjustable steel brackets, anchored by expansion bolts or embedded steel plates to improve pull-out and lateral resistance and prevent outward tilting and displacement of guide rails. The verticality of guide rails can be adjusted on site to eliminate additional stress caused by installation deviation and avoid jamming and deformation.

Middle wind-resistant ribs are installed for large door openings. Normally, the ribs are rolled onto the drum together with the curtain. When the curtain fully deploys in fire scenarios, the ribs automatically unfold and lock, laterally supporting the curtain surface, sharing wind pressure load, reducing mid-span deflection and controlling sealing gaps. The wind-resistant ribs are hinged to slats, balancing supporting rigidity and lifting flexibility.

The bottom sill plate adopts an integrated heavy-gauge steel profile. It compresses the curtain surface by its dead load to restrain mid-span sagging and wavy warpage of the curtain slats under wind pressure, ensuring reliable tight contact between the curtain bottom edge and the floor surface. Limit sliders are installed at both ends of the sill plate to restrict horizontal shifting and avoid rail jamming during curtain lifting and lowering.