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A ceiling radiation damper protects a membrane penetration in a fire rated floor or roof/ceiling assembly. They limit the radiant heat transfer through an air inlet/outlet opening and maintain the fire resistance integrity of the ceiling assembly during fire exposure. Ceiling radiation dampers are often mounted behind an air device such as a grille, diffuser, or mounted to a ceiling exhaust fan.

A fire damper is required in fire rated walls, partitions, barriers, and floors when they are penetrated by air ducts or other air transfer openings. To date, there are no UL approved Fire Dampers for installation in a ceiling. Corridor Fire/Smoke Dampers may be installed in the ceiling of a properly constructed “Tunnel Corridor” only. Refer to product installation manual for more details.

A ceiling radiation damper (CRD) should be installed in the following situations:

-        A CRD is installed where a duct penetrates the ceiling membrane of a fire resistance rated floor or roof/ceiling assembly. Note, through penetrations are not allowed.

-        A CRD installed at the ceiling line where a diffuser with no duct attached penetrates the ceiling of a fire resistance rated floor/ceiling or roof/ceiling assembly.

Refer to UL Product Directory for rated assembly details.

Assemblies that were tested with a generic hinged door style damper may use any UL 555C listed ceiling radiation dampers (examples: CRD-1, CRD-2, or CRD-60). They are typically installed in non-combustible ceiling design (i.e., steel truss) using a fire rated T-bar grid system.

Some floor or roof/ceiling assemblies are tested with manufacturer specific dampers that are specifically listed in the listing agency’s Product Directory. These are typically installed in combustible ceiling designs (i.e., wood joists or wood trusses) using a fire rated gypsum ceiling assembly.

Refer to UL Product Directory for rated assembly details.

There is one floor/ceiling and one roof/ceiling assembly listing that is dynamic rated M557 & P581, respectively. These specific assemblies are limited in scope in respect to opening sizes, market availability, subcomponent availability, and design flexibility.

Contact Greenheck Dampers for strategies to create a static system where Greenheck dampers are acceptable for use.

All UL rated floor/ceiling and roof/ceiling designs are based on fire testing conducted per UL Standard 263. The fire testing that was conducted to support most of the designs in UL’s Fire Resistance Directory was sponsored by component manufacturers (such as gypsum manufactures, damper manufacturers, etc.).

The sponsor (i.e., the “owner”) of the testing controls what manufactures can be listed in the design’s construction details. Manufacturers cannot test and list their products in those designs without the consent of the sponsor (i.e., in some cases, their direct competitor). Those designs can be considered “proprietary,” and some designs are limited to only one damper manufacturer.

(Note that some proprietary assemblies have additional damper manufacturers listed, and they can be either manufactured by, contract by, licensed by, or allowed by the test sponsor.)

As a result of this system, Greenheck conducted testing in accordance with UL555C and UL263 on an assembly allowing the use of Greenheck model CRD-1WT and CRD-2WT dampers. The components of construction, test standards and methods, fire resistance rating, and application are equal to many of the proprietary systems in the Product Directory.

Ultimately, it is at the discretion of the authority having jurisdiction to approve the installation.

Greenheck Model CRD-1WT and CRD-2WT are approved for use in the following UL Designs: L528, L546, L558, L562, L574, L576, L581, L583, L585, L592, M501, M503, M508, P533, P538, P545, P547, P548, P554, and P580.

Greenheck ceiling radiation dampers may require the use of a steel air device (grille, register, diffuser). Air devices with a non-ferrous core and steel frame may also be used. It is critical to adhere to the dimensions listed in the damper installation instructions detailing the maximum allowable distance the damper (with the blades in the closed position) can be above the plane of the membrane opening. Additionally, the design of the air device needs to be accounted for when planning the installation of the ceiling radiation damper. Double deflection grilles, grilles with opposed blade dampers (i.e., registers), and certain diffuser frame types may require installation clearances that may not allow for the correct installation of the damper. Consult Greenheck for ceiling radiation damper installation allowances and air device type and balancing recommendations.