smoke alarms and return vents

i have always understood that s.a.'s must be 3 feet away from return vents. did something change with the 2006 irc as I don’t see a reference to it?

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does nobody have an answer?

Never heard of that, are you thinking about a manufacturer’s recommendations?

tom

I’ve not heard of that rule either. What would the logic be for it? Actually, it would seem like a good spot to me. Any smoke in the home would be drawn towards the R/A if the AHU was running.

Thus potentially bypassing the alarm sensor…is the reason not within certain distance from returns, supplies and ceiling fans…

Follow the instruction that come with the alarm(s) an these links
http://www.nfpa.org/categoryList.asp?categoryID=278&URL=Research%20&%20Reports/Fact%20sheets/Smoke%20alarms

https://www.usfa.dhs.gov/downloads/pdf/publications/fa-250f.pdf

I don’t think you can go wrong if they adhere to these guidelines.

What others say on the other MB is hearsay without documentation, imo

hth

Additional helpful links Smoke Alarms and CO Detectors:

For more information about smoke alarms and specialized smoke alarms for the blind and hearing impaired, including talking, strobe (up to 177 candela), vibrating and amplified (up to 90 dB) smoke alarm products:
BRK Brands: www.brkelectronics.com or 1.800.323.9005
First Alert: www.firstalert.com or 1.800.323.9005
Gentex: www.gentex.com or 1.800.436.8391
Home Depot Supply: www.hdsupply.com
Kidde: www.kiddeus.com or 1.800.880.6788
MaxiAids (Provides a variety of products for special needs): www.maxiaids.com

http://www.cpsc.gov/CPSCPUB/PUBS/464.pdfhttp://www.usfa.dhs.gov/downloads/pyfff/inhome.html

http://www.epa.gov/iaq/co.html](http://www.epa.gov/iaq/co.html)

thanks. Barry. it’s the NFPA i was forgetting since the IRC makes no mention.

Smoke alarms are installed inside return duct, so what is the issue?

I glanced thru those references and don’t see where they recommend not placing the SD within 3’ of a R/A. Are you using the sentence that says “Don’t install smoke alarms near windows, doors, or ducts where drafts might interfere with their operation.”?

Can you help me out there and point that out to me so that I can make sure I change my inspection protocol? I’m sure it’s there, I just need a little help finding it.

kdkdkdk

Others might though…go ahead and post it. :stuck_out_tongue:

must be a regional thing. don’t see that around here.

Commercial, not so much in residential except the big stuff.

http://www.brkelectronics.com/downloads/installation/IN_SA_where_NOT_to_install.pdf

Areas to avoid for installation

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No mention of return air compartment or return air ducts. Makes sense as return air areas would pull the smoke there first. :smiley:

Many smokies are indeed place in the return ducts in commercial applications.

Hearsay indeed. :wink:

this may be what he’s thinking about.

Here is a duct smoke detector inside a return air duct.

This would shut down the ventilations system when it senses smoke and go into general alarm.

Hope this helps.

Marcel :slight_smile: :smiley:

Bingo! Different application as this is part of the FLS system…

Good one Marcel.

Tim

Smoke alarms and detectors shall not be installed within 36 inches horizontal path from the supply registers and should also be installed out of the direct airflow from those registers. Same thing with ceiling fans…36 inch horizontal path from the tip of the blades.

The commercial duct smokes have two pipes mounted on surface of the detector that poke into the duct. The airflow acts as a vacuum and a continuous sample of air goes through the detector. Any evidence of smoke shuts that unit down and system goes into alarm.

Good point about the ceiling fans. Never thought of that. Is that a manuf. or NFPA requirement?

From the 2007 version of the NFPA code …

NFPA 72
11.5.1.1*
Where required by applicable laws, codes, or standards for
a specific type of occupancy, approved single- and multiple-station
smoke alarms shall be installed as follows:
(1)*In all sleeping rooms and guest rooms
(2)*Outside of each separate dwelling unit sleeping area, within
6.4 m (21 ft) of any door to a sleeping room, the distance measured
along a path of travel
(3) On every level of a dwelling unit, including basements
(4) On every level of a residential board and care occupancy
(small facility), including basements and excluding crawl spaces and
unfinished attics
(5)*In the living area(s) of a guest suite
(6) In the living area(s) of a residential board and care occupancy
(small facility)

11.8.3.5
Specific Location Requirements. The installation of smoke
alarms and smoke detectors shall comply with the following
requirements:
(1) Smoke alarms and smoke detectors shall not be located where
ambient conditions, including humidity and temperature, are outside
the limits specified by the manufacturer’s published instructions.
(2) Smoke alarms and smoke detectors shall not be located within
unfinished attics or garages or in other spaces where temperatures can
fall below 4°C (40°F) or exceed 38°C (100°F).
(3) Where the mounting surface could become considerably warmer or
cooler than the room, such as a poorly insulated ceiling below an
unfinished attic or an exterior wall, smoke alarms and smoke detectors
shall be mounted on an inside wall.
(4) Smoke alarms and smoke detectors installed within a 6.1 m (20 ft)
horizontal path of a cooking appliance shall be equipped with an
alarm-silencing means or be of the photoelectric type.
(5) Smoke alarms and smoke detectors shall not be installed within a
914 mm (36 in.) horizontal path from a door to a bathroom containing a
shower or tub.
(6) Smoke alarms and smoke detectors shall not be installed within a
914 mm (36 in.) horizontal path from the supply registers of a forced
air heating or cooling system and shall be installed outside of the
direct airflow from those registers.
(7) Smoke alarms and smoke detectors shall not be installed within a
914 mm (36 in.) horizontal path from the tip of the blade of a
ceiling-suspended (paddle) fan.
(8 Where stairs lead to other occupied levels, a smoke alarm or smoke
detector shall be located so that smoke rising in the stairway cannot
be prevented from reaching the smoke alarm or smoke detector by an
intervening door or obstruction.
(9) For stairways leading up from a basement, smoke alarms or smoke
detectors shall be located on the basement ceiling near the entry to
the stairs.
(10)* For tray-shaped ceilings (coffered ceiling) smoke alarms and
smoke detectors shall be installed on the highest portion of the
ceiling or on the sloped portion of the ceiling within 305 mm (12 in.)
vertically down from the highest point.

Jeff

Smoke Detectors shall not be installed within 3’ of supplies, returns, ceiling fans and what have you. The smoke detector that is placed in a duct is a duct detector and it is usually placed on the return.