Another of US Duct’s resourceful “after the fan” products, flap exhaust valves, or stacks, are designed to open, like bird wings, with the airflow and close when the system is not exhausting. The lightweight and balanced blades produce minimal resistance to exhaust. The design of the housing and blades channel rainwater away from the opening and allow it to drain without intrusion into the ducting. The vertical profile of double flap exhaust stacks is shorter than non-loss stack heads so they require less vertical space.
Flap exhaust valves are available in galvanized and stainless steel. Heavy and light gauges are available to accommodate the needs of your system. Typical connection ends are flanged.