Heavy-duty, double-flanged, channel frame-style backdraft tornado dampers are designed to protect against tornados and rapid pressure changes. Installed in ductwork or wall mounted near the exterior of a building, the tornado dampers allow for air movement (intake or exhaust) during normal weather conditions. If a tornado passes near a building, the negative pressure caused by the tornado will cause the damper to close and prevent the collapse of the ductwork. Once the tornado has passed and the pressure equalizes, the spring-loaded blades will return the damper to its open position, and it will revert back to normal ventilation. Model HTOD-330 will close in the same direction as normal flow, and Model HTOD-331 will close in the opposite direction as normal flow.
Greenheck Fan Corp.
715-359-6171
www.greenheck.com
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