SMART VENT manufactures two UL-certified Fire Damper models. A masonry installation model (1540-530) and a wood wall installation model (1540-537). These fire dampers are certified to provide two hours of fire resistance. It is intended to be used in a situation in which fire proofing is required on a wall in which flood venting is installed, usually in a garage or vestibule. A fusible link holds a galvanized steel door in place. At 165°F (73.9°C), the link melts to permit the door to drop, blocking the path of the fire. Compatible with SMART VENT and FLOOD VENT models - The Fire Damper can safely be installed in the same cavity for either of the flood protection models, without interfering in their operation. Trim flange and inner sleeve are required for installation as well as a 8-inch minimum wall depth.