The RD-521-BT ceiling radiation damper employs butterfly style blades for point-of-origin control of radiant heat in HVAC systems. The RD-521-BT is installed horizontally in the ceiling membrane of combustible and non-combustible assemblies with fire resistance ratings up to and including 1 hour.
C&S Air Products Ceiling Radiation Damper, Model: RD-521-BT, Fire/Smoke Rating: 1 hr, Butterfly Blade, 30 ga Gauge, Steel, Finish: Galvanized, Horizontal Mounting, 165 deg F Fire Closure, Additional Information: 22 ga Steel Blade, 1 in W x 5/8 in D Plaster Ground, Fusible Link Closure Device