Fire Damper are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts to prevent the spread of fire inside the duct work through fire-resistance rated walls and floors.  Fire damper is a device designed to impede the spread of fire through walls, floors and partitions.  Its construction includes a galvanized steel frame and a fusible link, a heat sensitive device (usually set at 165° F). When the fusible link opens it releases the damper components to close.  When the damper components close the damper will restrict the migration of fire.  Fire damper products are listed with hourly ratings.  Made of Galvanized Iron or Stainless Steel.  Available in single blade or multi-blade system, square or round versions.  Can be with flanged type or non-flanged type.