LIFE SAFETY DAMPERS FAQS
Answers to your most Frequently Asked Questions about Greenheck life safety dampers.
Static-rated dampers are intended for use in HVAC systems that are automatically shut down during a fire event. They are not tested to close against airflow.
Dynamic-rated dampers are installed in HVAC systems intended to remain operational during a fire event and designed to close against airflow. Although not always recommended, dynamic fire dampers may be used in static systems, however, static fire dampers shall only be installed in static systems.
Always consult the International Building Code (and/or local code) and UL Product Directory for applications requiring static and dynamic ceiling radiation dampers.
Fire-rated barriers of less than three hours will typically use a 1-1/2 hour rated fire damper.
No, horizontal fire dampers are not tested for that specific application. Corridor fire/smoke dampers and ceiling radiation dampers are tested and approved for use with air outlets in rated floor/ceiling assemblies. Consult the International Building Code (and/or local code) and the UL Product Directory for floor/ceiling assembly requirements.
No, field modification of this nature is not allowable and will void the UL listing of the damper. Always consult the damper manufacturer before repairing or modifying a life safety damper.
No, you cannot use two smaller sections to build a damper in the field that exceeds the manufacturer’s maximum UL listing for that specific damper model.
Yes, steel mullions can be used to separate vertically mounted static fire damper in wall openings larger than the maximum UL listed multiple section damper assembly. They are only approved for use with 1½ hour static rated dampers in concrete block or poured walls with minimum 7 in. and maximum 12 in. thick. Other methods exist but are not specifically tested and must be approved the local Authority Having Jurisdiction (AHJ).
Greenheck does not offer support mullions for fire dampers for field installation, however, supplemental instructions on how to manufacture support mullions for static rated curtain dampers are available.
After consulting with Greenheck, a solution based on good engineering judgment should be evaluated and accepted by the local Authority Having Jurisdiction (AHJ).
Greenheck can manufacture a combination fire smoke damper that is 8 in. x 8 in. with an internally mounted electric actuator.
Yes, Greenheck has a UL approved grille installation supplement for standard combination fire smoke dampers and offers out-of-wall combination fire smoke dampers (OFSD or GFSD) that may also be used for this application.
Yes, there are specific models that have been tested and evaluated for this application and will be labeled for out-of-wall use (GFSD or OFSD).
No, most dampers have been tested and approved for installation without the use of any type of firestop. Additionally, most fire and combination fire smoke dampers require a thermal expansion air gap between the damper assembly and the wall. No materials should be used to fill this gap unless specifically stated in the damper’s UL approved installation instructions.
Damper sleeves and retaining angles can be factory or field supplied. Consult Greenheck’s installation instructions for details.
Minimum size and thickness can vary by manufacturer. For Greenheck dampers, the minimum size is 1½ in. by 1½ in. (38 mm x 38 mm). For dampers up to 36 in. (914 mm) wide and 24 in. (610 mm) high, the minimum thickness is 16 gauge. For larger dampers, the minimum thickness is 14 gauge.
No, the single sided retaining angle method is to only be used on 1½ hour rated dampers.
Two-sided retaining angles should only be anchored through the damper sleeve to allow the damper the ability to operate properly in a fire condition. Single-sided angles require a fastener through both the damper sleeve and to the opening.
Greenheck fire and combination fire smoke dampers are tested and approved for installation without the use of sealant on the retaining angles. If sealant is required, consult Greenheck’s supplemental installation instructions for approved sealants.
As of June 1, 1999, UL 555S requires all smoke and combination fire smoke dampers to ship from the factory with actuators installed.
NFPA 80 and 105 details maintenance requirements of fire and smoke dampers, respectively. Both standards allow for the repair of inoperable dampers. The replacement actuator must be equal to or greater in temperature and torque rating, as well as operation (2-position vs. modulating), to that of the original actuator. Consult Greenheck for specific details on approved actuators prior to replacement.
Yes, smoke and combination fire smoke dampers can also be approved for use as HVAC control dampers and use a 24 VAC/VDC actuator designed to accept a 2 to 10 VDC control input, or a 4 to 20 mA control input from an electronic controller or positioner. See Greenheck models FSD-211M or FSD-311M for more details.
No, sleeves and mounting angles are not required to maintain the UL listing of a smoke damper, however they may be used to facilitate installation at the contractor’s discretion.
Greenheck offers both a low flow and no flow smoke detector option on our smoke dampers and combination fire smoke dampers. Smoke detectors can be shipped loose or factory mounted.
Breakaway connections are used so the damper/sleeve assembly can separate from the duct if the structure starts to fall during a fire. The breakaway joint allows the damper to remain in the wall for maximum protection. Approved breakaway connections are listed in Greenheck’s UL approved installation instructions.
NFPA 80 and 105 details the maintenance and periodic testing requirements of fire and smoke dampers, respectively. Both standards allow for the repair of inoperable dampers and the addition of position indication functionality. Other modifications may be required due to application or field conditions. Actuator replacement, external to internal actuator conversion, and in-wall to out-of-wall damper conversions are examples of common modifications.
Once a listed damper leaves the factory, the Authority Having Jurisdiction (AHJ) must approve subsequent field modifications. Manufacturers may offer guidance and have supplemental instructions on how to modify a damper in the field. Sometimes the AHJ or Owner may require UL to determine the suitability of the modification before approving it and in that case a UL Field Evaluation may be required.
The damper location for all Greenheck multiblade dampers (FSD, SMD, VCD and DFD, and DFDAF series) refers to the A dimension (the distance from end of sleeve to face of damper). The minimum allowable A dimension is 7.188 in. (182.6 mm). The damper location for curtain-style fire dampers (FD and DFD) refers to the K dimension (the distance from end of sleeve to centerline of damper frame).
An OCI provides feedback to a control panel using a direct connection to the damper blades to indicate if the blades are in an open or closed position. An auxiliary switch is integral to the actuator that provides feedback using the stroke position of the actuator to indicate if the blades are in an open or closed position.