The Forecast Production Assistant

A fire damper for use in small openings comprises a single blade articulated about a hinge within a frame, which blade is movable between an open and closed position. In the open position a fusible link and strap retain the blade. When the link is released a negator extension-type spring mounted on the frame forces the blade to close the opening through the frame. A blade lock mounted on the blade engages the frame to retain the blade in the closed position.