Design
Surrounded by a 3/8 inch flange, the SR attaches firmly to the inside wall of the main shaft, eliminating the possibility of loose or disconnected risers. The SR provides the minimum 22 inch rise while maintaining a low profile within the main exhaust shaft. Using SR risers as an alternative to conventional field-erected sub-ducts results in lower velocities and less restriction in the main shaft. This allows for smaller main shafts with less generated noise.
