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UL 521 Listed
Basis of Design
Multifamily Ready
Fast Lead Times

UL Rated, Fire, Smoke, and Ceiling Radiation Dampers /Ceiling Radiation Dampers /Wood Truss Systems /Duct Board Outlet Box

RD-521-NP

1 Hour - Ceiling Radiation Damper

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Common Applications

  • Wood Truss Assemblies
  • Multifamily
  • Light Commercial

Resources

Product Sheets

  • PDF RD521-NP Product Sheet
  • PDF RD-Operation and Maintenance

Installation Instructions

  • PDF RD521(IP/NP) Installation
  • PDF Fire Rated Duct Board Plenum
  • PDF RD521-BT/IP/NP/90 Installation
  • PDF Steel Plenum

Overview

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

Standard Construction

Frame: 22 ga. (0.85) galvanized steel.
Blades: 22 ga. (0.85) galvanized steel - butterfly. Insulated with ceramic refractory material for dampers larger than 114 in.2 (735 cm2)
Transition: None (field adaptation required.)
Plaster Ground: 5/8" (16) deep x 1" (25) wide.
Closure Device: Fusible Link.
Fire Closure Temperature: 165oF (75oC).
Minimum Size: 4" x 6" (102 x 152)
Maximum Size: Square: 16" x 16" (406 x 406)
                           Rectangular: 24" (610) W or 20" (508) H
                           with a maximum area of 256 in.2 (1652 cm2).

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