90 minutes fire rated Cladded Duct System - PROMATECT®-L500
- Assembling a single layer of PROMATECT®-L500 board, 15mm thick, cladded to steel duct and secured with screw-fixing the galvanised steel angle at all four corners of the board to form an encasement and to the channel collar frame at the board joints. Infill the encasement with mineral wool insulation. Cover strips over the butt-joints.