smoke alarms and return vents

[Richard W. Washington]

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?

[Richard W. Washington]

does nobody have an answer?

[Thomas H. Dietrich]

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

tom

[Michael R. Boyett]

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.

[Barry Adair]

Originally Posted by mboyett

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&%2 0Reports/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

[Richard W. Washington]

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

[David A. Andersen]

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

[Michael R. Boyett]

Others might though...go ahead and post it.

[Richard W. Washington]

Originally Posted by dandersen

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

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

[David A. Andersen]

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

[Brian E. Kelly]

Originally Posted by badair

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

http://www.brkelectronics.com/downlo...to_install.pdf


Areas to avoid for installation

• Near fresh air vents, ceiling fans, or in
very drafty areas. Drafts can blow
smoke away from the unit, preventing
it from reaching the sensing chamber

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

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

Hearsay indeed.

[David A. Andersen]

Near fresh air vents

this may be what he's thinking about.

[Marcel R. Cyr]

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.

Attachment 21527

Hope this helps.

Marcel

[Tim Spargo]

Originally Posted by mcyr

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.

Attachment 21527

Hope this helps.

Marcel

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

Good one Marcel.

Tim

[Jeffrey R. Wicklander]

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.