# Operation of Smoke Dampers



## hbendillo (Sep 26, 2014)

I have an issue on a project where there  is a smoke damper in a wall separating two return air plenums.  Between two corridors actually. Is it acceptable to install a smoke detector in the plenum at the damper for operation?


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## cda (Sep 26, 2014)

No

Follow mechanical code and nfpa 72

Will try to find some code sections


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## hbendillo (Sep 26, 2014)

OK. I appreciate it.  The reason I ask is because I am pretty sure if I had a ducted return, I could install a duct detector on one or both sides of the damper for operation.  I just figured a plenum rated smoke detector might serve the same purpose. My other option is to install area detectors on the corridor ceilings.


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## steveray (Sep 26, 2014)

1018.5.1 Corridor ceiling. Use of the space between the corridor ceiling and the floor or roof structure above as a return air plenum is permitted for one or more of the following conditions:

1. The corridor is not required to be of fire-resistance-rated construction;

2. The corridor is separated from the plenum by fire-resistance-rated construction;

3. The air-handling system serving the corridor is shut down upon activation of the air-handling unit smoke detectors required by the International Mechanical Code;

4. The air-handling system serving the corridor is shut down upon detection of sprinkler waterflow where the building is equipped throughout with an automatic sprinkler system; or

5. The space between the corridor ceiling and the floor or roof structure above the corridor is used as a component of an approved engineered smoke control system.


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## mtlogcabin (Sep 26, 2014)

716.3.3.2 Smoke damper actuation.

The smoke damper shall close upon actuation of a listed smoke detector or detectors installed in accordance with Section 907.3 and one of the following methods, as applicable:

1.	Where a smoke damper is installed within a duct, a smoke detector shall be installed in the duct within 5 feet (1524 mm) of the damper with no air outlets or inlets between the detector and the damper . The detector shall be listed for the air velocity, temperature and humidity anticipated at the point where it is installed. Other than in mechanical smoke control systems, dampers shall be closed upon fan shutdown where local smoke detectors require a minimum velocity to operate.

2.	Where a smoke damper is installed above smoke barrier doors in a smoke barrier , a spot-type detector listed for releasing service shall be installed on either side of the smoke barrier door opening.

3.	Where a smoke damper is installed within an air transfer opening in a wall, a spot-type detector listed for releasing service shall be installed within 5 feet (1524 mm) horizontally of the damper .

4.	Where a smoke damper is installed in a corridor wall or ceiling, the damper shall be permitted to be controlled by a smoke detection system installed in the corridor .

5.	Where a total-coverage smoke detector system is provided within areas served by a heating, ventilation and air-conditioning (HVAC) system, smoke dampers shall be permitted to be controlled by the smoke detection system.

I, 3, or 5 are the options available. We usually see the damper installed in a sleeve and 4 ft of ductwork installed on both sides of the wall  and the detector installed within this short run of duct so basically it complies with #1


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## cda (Sep 27, 2014)

mtlogcabin said:
			
		

> 716.3.3.2 Smoke damper actuation.The smoke damper shall close upon actuation of a listed smoke detector or detectors installed in accordance with Section 907.3 and one of the following methods, as applicable:
> 
> 1.	Where a smoke damper is installed within a duct, a smoke detector shall be installed in the duct within 5 feet (1524 mm) of the damper with no air outlets or inlets between the detector and the damper . The detector shall be listed for the air velocity, temperature and humidity anticipated at the point where it is installed. Other than in mechanical smoke control systems, dampers shall be closed upon fan shutdown where local smoke detectors require a minimum velocity to operate.
> 
> ...


good answer, just have not seen a detector in duct work in a very long time


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