The Fire Damper for Smart Vent Masonry Units are UL Certified to provide 2 or 3 hour Fire Resistance. They are intended to be used when it is necessary to install flood vents into fire-rated wall in conjunction with Smart Vent Flood Vent Models.
A fusible link holds the galvanized steel door in place. At 165˚F, the link will melt allowing for the door to drop closed, blocking the path of the fire..