Ceiling dampers are designed to function as a heat barrier in air duct openings penetrating fire resistive membrane ceilings.  The 0700 Series is for use in lieu of hinged door type dampers in any UL/ULC floor/ceiling or roof/ceiling assembly with up to a 3-hour fire resistance rating where air ducts are permitted.

The Basics of Ceiling Dampers

It is important that we understand some of the theory behind fire ratings of ceilings and the purpose of the various devices used to maintain the integrity of these assemblies.  A fire-rated ceiling protects the structure from excessive heat and potential subsequent collapse.  Properly installed, it provides a barrier to heat between the fire area and the floor above.  Without openings (for lights, grilles, diffusers, etc.) no problems are encountered.

Unfortunately, owners and tenants keep insisting in some environmental control and our industry in response punches great holes in these protective ceilings.  To close these openings in emergencies, devices called Ceiling Dampers have evolved.

A Ceiling Damper is subjected to severe testing to prove the ability to prevent the transfer of heat in concentration from a fire area to the structure above.  A definite funnel effect is created at openings in rated ceiling assemblies and the Ceiling Damper is specific to protection against this phenomenon. (See Figure 1).

FIGURE 1.

A conventional fire damper, being virtually transparent to heat, is almost useless to this application.
The following is a definition of a Ceiling Damper (quoted from typical building code):
"…a device intended for use in horizontal assemblies required to have a fire resistance rating and incorporating protective ceiling membranes which operates to close off a duct opening through the membrane in the event of a fire."

The Nailor Model Series 0700 ceiling dampers have been tested and listed by UL/ULC to meet all of the criteria for restrained and unrestrained ceiling assemblies up to 3 hours.