Subduct Riser Manufacturing offers low-profile subduct risers made of 26 gauge galvanized steel. The LSR is beneficial in applications where a 22 inch subduct riser is necessary to maintain the fire and smoke rating of an exhaust shaft instead of using fire and smoke dampers. The LSR is IBC- and IMC-compliant for bathroom, kitchen, and clothes dryer exhaust shafts.

The LSR is available with female inlet connections of 4, 5, 6, 8 and 10 inches.  Surrounded by a 3/8 inch flange, the LSR attaches firmly to the inside wall of the exhaust shaft, eliminating the possibility of loose or disconnected risers. The LSR pro-vides the minimum 22 inch rise while maintaining a low profile. Using LSR risers as an alternative to conventional field-erected subducts results in lower velocities and less restriction in the main exhaust shaft allowing for smaller main shafts with less generated noise.