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Compliance   •   Installations   •   Commissioning
Combination of
Fire Smoke Dampers
We Inspect, Install, Test and Repair
Closed Smoke Damper
Open Smoke Damper

Applicable Standard (From the NFPA Code books)


"NFPA 101, Sec.9.2.1 requires that air conditioning, heating, ventilating ductwork and 

related equipment be in accordance with NFPA 90A, Standard for the Installation of Air-

Conditioning and Ventilating Systems, or NFPA 90B, Standard for the Installation of Warm Air 

Heating and Air-Conditioning Systems, as applicable.  Since NFPA 90B is intended to apply only

to one-and two family dwellings and spaces not exceeding 25,000 ft3 in volume, the information

contained in this guide will be based on requirements found in NFPA 90A.  The 1999 edition of

that standard is referenced in NFPA 101, Sec. 2.1.1.


Testing of Combination Fire Smoke Dampers


There are several methods to test or activate these dampers.  NFPA provides many detailed

requirements and your AHJ will utilize this guideline to your specific building operation for the

intended use.  Our company can customize the inspection to assist the intent for the inspection.

The following are methods of testing combination fire smoke dampers.


• Placing a building in alarm to verify the operation of smoke dampers.  This is critical to ensure system operation but this is the least desirable method of testing.  The disruption to the building occupant with the audible and visual alarms and temperature issues caused by shutting down the building HVAC systems.  Many times this caused operational issues to the HVAC systems over continued testing in this manner.

• Testing of the associated duct or smoke detector.


There are three methods to test this typeof activation:

1. Smoke-Using a test canister of sample smoke to activate these devices. Testing the duct detector and smoke detector are sometimes covered under the fire system testing but do not cover actual damper operation inspections.  We ensure the criteria of testing the combination fire smoke damper are met utilizing this method.

2. Remote test switch attached to a duct detector–When applicable this method is utilized. Although this method does test the functionality of the detector and associated damper, again, testing in this manner can causes HVAC related issues.

3. Magnet–Although this is not an approved method to test a duct or smoke detector, we are only concerned with the functional test of the associated damper and not the functional test of the detector.    

(Many systems utilizing duct and smoke detectors to activate the fire smoke dampers will have associated indicating systems.  When applicable these will also be inspected for operation.)


•    Removal of power – Shutting down the breaker or breaking the circuit to test the functionally of the damper.  Many times this is the method we use.  Since working with live voltages in confined spaces this is sometime dangerous this is not the preferred method for these reasons.

•    Test switch – When installed is our preferred method.


Air Duct Service Openings

It’s next to impossible to properly maintain your fire and smoke dampers unless you have

adequate access to them.  To that end, NFPA 90A requires that service openings be provided in

air ducts adjacent to each damper [see Sec. 2-3.4.1].  Obviously, the openings need to be

conveniently located and large enough to allow for maintenance and resetting of the devices.  It’s

important to note that there could be times when it may be necessary to get two arms into the 

duct.  While no specifics are spelled out in the standard, NFPA 90A(99), Sec. A-2-3.4.1 offers the

following guidance relating to service openings:

•    Where the size of the duct permits, access doors should be at least 18 inches x 16 inches is size.

•    Where fire dampers are too large to allow them to be reset and the fusible link replaced from

outside the duct, the access doors should be increased to at least 24 inches x 16 inches in size to

allow a person to enter the duct.

•    The doors for fire dampers should be located so that the spring catch and fusible links are 

accessible when the damper is closed.

•     The doors should be located as close as practicable to the dampers.

•     It’s recommended that access doors be located on the underside of ducts rather than on the side.

Other things to keep in mind....

•    NFPA 90A (99), Sec. 2-3.4.2 requires that service openings be identified with letters at least 1/2 inch in height indicating the location of the damper within.

•    While inspection windows are allowed in air ducts (so long as they’re glazed with wired glass),

they do not replace the required access doors [see NFPA 90A(99), Sec. 2-3.4.4].

•    Openings need to be provided in walls or ceilings to allow for access to the service openings in your air ducts [see NFPA 90A(99), Sec. 2-3.4.5].

CAUTION:  Care must be taken to ensure that any access panels or drop-in ceiling tiles used to

provide this access do not reduce the fire resistance rating of your floor ceiling or roof ceiling


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