Model RD-521

1 Hour - Ceiling Radiation Damper
Butterfly Style Blade

The RD-521 ceiling radiation damper employs butterfly style blades for point-of-origin control of radiant heat in HVAC systems. The RD-521 is installed horizontally in the ceiling membrane of combustible floor-ceiling or roof-ceiling assemblies with fire resistance ratings up to and including 1 hour.

Standard Construction

Frame: 22 ga. (0.85) galvanized steel with integral outlet box.
Blades: 22 ga. (0.85) galvanized steel - butterfly. Insulated with ceramic refractory material for dampers larger than 114 in² (735 cm²).
Transition: Round, with 2" (51) deep collar, located on W side of outlet box.
Plaster Ground: 5/8" (16) deep x 5/8" (16) wide.
Closure Device: Fusible Link.
Fire Closure Temperature: 165^oF (75^oC).
Minimum Size: 4" x 6" (102 x 152)
Maximum Size: Square: 18" x 18" (457 x 457)
                           Rectangular: 24" (610) W or 20" (508) H with a maximum area of 324 in² (2090 cm²)

Ratings

UL 555C Fire Resistance Rating: 1 hour for installation in floor designs
L-521, L-546, L-558, L-562, L-576, L-581, L-583, L-585 and
in roof/ceiling designs P-522, P-533, P-538, P-545 and P-547.

UL 555C Listing: R14980
CSFM Listing: 3226-1404:100
Warnock Hersey Listing #: WHI-495-PSH-0177, -0178
Meets NFPA Standards: 90A and 101
Meets Building Code Standards: IBC, NBC, NFPA, SBC and UBC