The Science of The Fire Damper
Fire Dampers are devices designed to restrain the spread of fire through floors, walls and partitions. Built with a galvanized steel frame, a fusible link or a thermo sensitive device (ETL – usually set at 165° F). If the fusible link opens, the Fire Damper will release the damper components to close. Once the components close the Fire dampers will stop the transfer of fire from one room to another. Fire damper come in different shapes and hourly ratings to meet your specific needs.
Which Fire Damper?
Often referred to as a static fire damper, these are the most common fire damper and are considered the industry standard for 1 ½ hour fire rating. They are available in all orientations, sizes and are available with or without sleeves. A UL listed link reacts to heat and releases the curtain which shuts via spring or gravity.
CRD’s as they are referred to, are specific to protecting ceilings only, for ceiling with a fire resistance ratings of 3 hours. They are available in round, rectangular, square, pre-made assemblies (boots/cans), and in low profile “blanket” style. A UL listed link reacts to heat and releases the curtain which closes them via a spring.
FSD are complete UL rated assemblies that include a sleeve, electrically operated smoke damper and link + spring for temperature released override. Connected to smoke detector systems they have electric or pneumatic actuators and are used in public facilities for hallways and corridors smoke/fire protection.
Dynamic fire dampers are a spring loaded fire damper, just like the curtain style, used in high velocity circumstances. They are rated for 4.0 WG, and are also used in situations where the smoke alarm does not shut off the air handler fan. Note: The term “Dynamic” is often times misused to just mean spring loaded.
All installed fire dampers must be accessible for inspection and/or testing by the local authorities. If fire dampers are not accessible from a grill, register, or by removing flex duct, an access door in the duct work is required. There are fired rated access doors, finished doors, and the standard cam & cam or cam & hinge.
There are quite a few accessories associated with fire dampers. We have Duct Smoke Detectors, choices for sleeves, choices for mounting angles, various access doors, replacement fuse links and varying temperature fuse links. All of the various mounting instructions and an installation video are available for your reference.