Broan-NuTone 110RDF 110Cfm Blower W/Metal Grille Since their beginning in 1932, Broan has pioneered many of the product innovations now established as standards of the industry. Today, Broan carries on the commitment to provide the finest products i n the industry. Many local codes require that exhaust fans installed in fire-rated ceilings must be protected by dampers, which, in case of fire, protect against the spread of heat and flame. Being fire-rated means the ability of a wall, floor/ceili ng, or roof/ceiling to withstand the effects of fire for a specified period of time. Broan ceiling radiation dampers are designed to protect the openings in 1-, 2-, or 3-hour fire-rated floor-ceiling and roof-ceiling designs. When the temperature of the air passing through the damper exceeds 165°F, the fusible link melts and the thermal fabric across the damper closes automatically to interrupt the airflow by becoming a flame and heat barrier, preventing rapid spread of fire to other areas. Broan-NuTone 110RDF 110Cfm Blower W/Metal Grille Features: • Bath Fans, Radiation Dampers • Finish Pack, 110 CFM Blower, 4.0 Sones, with Metal Grille. To be used with Model RDH housing pack. • Housings and finishes (motor assembly and grille) sold separately in units of four per carton - purchase housings for rough-in and blower assemblies/grilles later for finishing • UL classified (UL standard 555C) for use in 1-, 2-, or 3-hour fire-rated floor-ceiling and roof-ceiling des igns • High temperature, non-asbestos, reinforced fiber thermal fabric • Galvanized steel frame • 165°F fusible link • Stainless steel negator-type closure spring • Available from 50 CFM to 110 CFM • Radiation damper comes attached to housing • Blower assembly will fit into housing without the removal of the radiation damper - one less step in installation process