# smoke detector height on walls



## Dave Buckley

I have four residential lofts with hard wired interconnected smoke detectors and 20 ft ceilings. The electrician has installed the smoke detectors on the walls between 10 and 12 ft high. The last time I looked at NFPA the requirement was 4 to 12 inches down from the ceiling. Has anyone had experience with this?


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## steveray

Manufacturers installation instructions....Pretty sure the electrician is wrong.


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## JBI

Manufacturers specifications?


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## FM William Burns

Electrician is and most by trade often wrong and notorious for improper mounting.  Have the electrician install them in accordance with NFPA 72 [29.8.3 for type of ceiling/wall] as referenced by R314.2 if SF Homes if IBC all the same for this scenario.


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## Builder Bob

When all else fails, use NFPA 72 for requirements for locations - it is referenced by the IRC>

*R314.1 Smoke detection and notification. *

All smoke alarms shall be listed and labeled in accordance with UL 217 and installed in accordance with the provisions of this code and the household fire warning _equipment _provisions of NFPA 72.

NFPA 2010 Sections 29.8.3.2 Sloped Ceilings; 29.8.3.3 Wall Mounting- "shall be located no farther than 12" from the adjoining ceiling surface."

This accessible for free on NFPA.


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## cda

> I have four residential lofts with hard wired interconnected smoke detectors and 20 ft ceilings. The electrician has installed the smoke detectors on the walls between 10 and 12 ft high. The last time I looked at NFPA the requirement was 4 to 12 inches down from the ceiling. Has anyone had experience with this?


What builder bob said

Plus the instructions are in the box

Plus vaulted ceilings are a pain, but they need to be there.

Where is the sleeping area?? One level loft???


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## RFDACM02

Again there's the Code then there's what is functional. While most often the higher the better for rapid response (other than the 4-12 " down thing, which I believe I read might go away), the issue in residential is can the owner test it monthly? Can they change the batteries? If the unit is too far from reach it may result in complications and thus the installer should really determine the best and most functional location that meets the code. On the FD response side, we see vaulted ceiling detector issues quite a bit as no one touches them until they fail and then they call us, we have ladders.


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## cda

> Again there's the Code then there's what is functional. While most often the higher the better for rapid response (other than the 4-12 " down thing' date=' which I believe I read might go away), the issue in residential is can the owner test it monthly? Can they change the batteries? If the unit is too far from reach it may result in complications and thus the installer should really determine the best and most functional location that meets the code. On the FD response side, we see vaulted ceiling detector issues quite a bit as no one touches them until they fail and then they call us, we have ladders.[/quote']Ten year battery units
> 
> Which will become mandated one day


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## FM William Burns

Dave,

Appears I've lost some street credit here with some but here is the free access to all NFPA codes as mentioned by my esteemed retired colleague BB:

http://www.nfpa.org/codes-and-standards/document-information-pages

(1) Click on the link *Free access to the 2016 edition of NFPA 72* 

(2) Set up a free account (follow prompts)

(3) Scroll down the list to NFPA 72 and click tab (Current & Prior Edtions)

(4) Click drop down year top 2010

(5) Click

*View the document online (Free Access)*  Free access to the 2010 edition online

Best Wishes,

FMWB

P.S. It is correct as *RFDACM02* mentions the 4/12 rule has gone away but the installation methodology regarding dead areas as the referenced figures in the code reference are still accurate


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## cda

Shows vaulted ceiling install

http://www.nfpa.org/safety-information/for-consumers/fire-and-safety-equipment/smoke-alarms/installing-and-maintaining-smoke-alarms


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## cda

> Dave,Appears I've lost some street credit here with some but here is the free access to all NFPA codes as mentioned by my esteemed retired colleague BB:
> 
> '>http://www.thebuildingcodeforum.com/forum/member/11173-rfdacm02"]*RFDACM02* mentions the 4/12 rule has gone away but the installation methodology regarding dead areas as the referenced figures in the code reference are still accurate


Dead space is gone/ 12 inch max is still there.

"""Generally speaking, you can best locate a smoke alarm or smoke detector on the ceiling. However, the code permits wall mounting. The biggest change in NFPA 72 2010 regarding wall mounting of smoke detectors comes from the removal of the requirement to avoid locating smoke alarms and smoke detectors in what was known as the 4-inch “dead-air” space at the ceiling wall juncture. You may now install a smoke alarm or smoke detector on the side wall 12 inches down for the ceiling-wall interface. And, for tray-shaped ceilings (coffered ceilings), you must install smoke alarms and smoke detectors on the highest portion of the ceiling or on the sloped portion of the ceiling within 12 inches (300 mm) down vertically from the highest point."""""

http://www.ecmag.com/section/codes-standards/return-normalcy


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## JBI

FMWB, "Appears I've lost some street credit here with some..." BUT not with all of us. :tennis:


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## cda

> FMWB' date=' "Appears I've lost some street credit here with some..." BUT not with all of us. :tennis:[/quote']He does not have a micro chip in his credit, that is the problem.


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## FM William Burns

I meant to type the 4" dead rule area but accidently typed 4/12.  Thanks for cleaning it up CDA.


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## RFDACM02

> Ten year battery units
> 
> Which will become mandated one day


I agree and am looking forward to it, but those difficult to reach places will still pose a functionality problem as they cannot be routinely checked, cannot be "hushed" and cannot be cleaned or blown out readily. Much like fie extinguishers the reason for the monthly check is to ensure a bad one doesn't go a year until it's recognized, thus 10 years without being checked could lead to many failures not being recognized until too late. Plus, I doubt any manufacturer will eliminate that routine test, thus washing their hands of those problems. But, for nearly every routine application, I think they're awesome.


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## RFDACM02

> Dave,P.S. It is correct as *RFDACM02* mentions the 4/12 rule has gone away but the installation methodology regarding dead areas as the referenced figures in the code reference are still accurate


I don't think this has gone away, but I recall an article somewhat recently speaking to that effect based on testing disproving the theory that smoke doesn't reach the corners?


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## RFDACM02

Whoops, didn't read carefully or far enough, so it appears that the upper limit has actually been lifted? It should be somewhat obvious that too low will just delay alarm activation, so that would seem to be a keeper! Thanks to FMWB and CDA for the update.


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## conarb

I was looking forward to hard wired smokes so we wouldn't have batteries to change in our high ceilings, then I find out that they have battery backups. In the last house I built I got a call from the owner telling me that his batteries were chirping within one year of finishing the homes, and both batteries were over 20' high so he couldn't change them, I had to call my electrician to go out with a 16' ladder and stand on the top of the ladder, the second time they started chirping I took the batteries out of all the high ones as they started chirping. Let's face it they are still actuated by hard wiring and all the lower ones in the home still have battery backups.


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## Francis Vineyard

For a number of years security companies will install an independent fire alarm system where all the alarm/detectors are hardwired with DC voltage to a central panel. The panel is plugged into a 120 volt 15 amp receptacle provided with a single 9 volt lantern type battery for back up in compliance with the code.

However it would still be the owners responsibility to clean the detectors as I'm certain we all do.


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## FM William Burns

> I was looking forward to hard wired smokes so we wouldn't have batteries to change in our high ceilings' date=' then I find out that they have battery backups. In the last house I built I got a call from the owner telling me that his batteries were chirping within one year of finishing the homes, and both batteries were over 20' high so he couldn't change them, I had to call my electrician to go out with a 16' ladder and stand on the top of the ladder, the second time they started chirping I took the batteries out of all the high ones as they started chirping. Let's face it they are still actuated by hard wiring and all the lower ones in the home still have battery backups.[/quote']You can always install a smoke detection "system" in accordance with the residential chapter of 72. Now wireless is approved in 72 so you could only have to replace a couple main batteries for the required secondary power supplies or connect to a home's generator that meets NFPA 110 and then only ladder work will be detector replacement when they fail sensitivity requirements..............


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