• 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.
Model RDA with Model HD50RDB is ENERGY STAR® qualified.
• UL classified (UL standard 555C) for use in 1-, 2-, or 3-hour fire-rated
floor-ceiling and roof-ceiling designs.
• Warnock Hersey Listing allows use in combustible ceilings with ducted fans.
• 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.
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/ceiling, or roof/ceiling to
withstand the effects of fire for a specified period of time. NuTone 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.