Model RD-521-90

1 Hour - Ceiling Radiation Damper
Field Installed 90° Plenum - Butterfly Style Blade

The RD-521-90 ceiling radiation damper employs butterfly style blades for point-of-origin control of radiant heat in HVAC systems. The RD-521-90 is installed horizontally in the ceiling membrane of combustible and non-combustible assemblies with a fire-resistance rating up to and including 1 hour.

Standard Construction

Frame: 22 gauge (0.85) galvanized steel.
Plenum Outlet Box: 28 gauge (0.47) galvanized steel.
Blades: 22 gauge (0.85) galvanized steel – butterfly insulated with ceramic refractory material.
Plaster Ground: 5/8" (16) deep x 7/8" (22) wide.
Fire Closure Device: Fusible link.
Fire Closure Temperature: 165°F (75°C).
Minimum Size: Grille Opening — 4" x 6" (102 x 152), Duct — 4" Ø (102 Ø).
Maximum Size: Grille Opening — Square: 12" x 12" (305 x 305), Rectangular: 14" (356) W or 10" (254) H with a maximum area of 144 in2. (929 cm2), Duct - 10” Ø (254 Ø)

Ratings

UL 555C Fire Resistance Rating: 1 hour (horizontal, for use in UL assemblies L-521, L-528, L-546, L-558, L-562, L-574, L-576, L-581, L-583, L-585, M-509, M-540, P-522, P-533, P-538, P-545, P-547, P-579, and P-580.

UL 555C listing: R14980
CSFM listing: 3226-1404:100
Meets NFPA Standards: 90A and 101
Meets Building Code Standards: IBC, NBC, NFPA, SBC and UBC