The CFD-521-NP ceiling radiation damper employs butterfly style blades for point-of-origin control of radiant heat in HVAC systems. The CFD-521-NP 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. The CFD-521-NP must have a field assembled insulated duct board outlet box installed on it.

PCI Industries RD-521-NP Fire Damper, 4'' x 8''