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#49995 03/22/05 06:20 PM
Joined: Mar 2002
Posts: 179
derater Offline OP
Job is bedroom w/ 1)laundry 2)office areas partitioned from bedroom.I'm thinking smoke detectors in all three areas; correct?
thanks up front

#49996 03/22/05 08:48 PM
Joined: Dec 2003
Posts: 524
..Derater,I may be wrong,(in this instance)but anytime I wired an addition,it fell under the Rehab Code,and interconnected smokes were required throughout the residence,if already installed,then the required smokes were to be added to them(interconnected)..I always make a point to pow-wow with the local Fire Official,meet him at the site,and let him tell me where he'd like them cuts out alot of guess work,and redundant work..Good Luck.. [Linked Image] [Linked Image]

[This message has been edited by Attic Rat (edited 03-22-2005).]

.."if it ain't fixed,don't break a Licensed Electrician"
#49997 03/22/05 08:58 PM
Joined: May 2003
Posts: 2,876
e57 Offline
As far as working in existing structures, it all falls on the local AHJ.

For instance: I would not have to put smokes in any of the areas you mentioned. (Except that office/bedroom if bed area didn't already have one.) But I only need to add smokes if work is valued at $1000 or more. And only need to be hard wired and interlinked if scope of work includes open rock cieling in the area. Other-wise Batt. op's are OK. And if it is wide open for a full remodel, I only need to do Stairs, halls (15' or < for each BR), and the BR's themselves.

Botton line, its a quick call to the appropriate Inspector.

Mark Heller
"Well - I oughta....." -Jackie Gleason
#49998 03/22/05 09:09 PM
Joined: Jul 2004
Posts: 9,928
Likes: 34
Is there a good web site that lays out what optimum smoke detector locations should be. I am fixin to redo all the mismatched battery smokes in my house with an interconnected AC system and I want the best bang for my buck/work.

Greg Fretwell
#49999 03/23/05 10:51 AM
Joined: Jan 2005
Posts: 5,445
Likes: 3
Cat Servant
Smoke detectors, smoke detectors...again!

The basic requirements for the placement of smoke detectors in a residence are as follow:
-in every sleeping area;
-in every hall serving a sleeping area-
-wherever there is a radical change in ceiling height- such as a 'catherdal' living room ceiling- that might provide a "pocket" in which smoke might accumulate (or be trapped).

Additionally, it is reccomended that smoke detectors NOT be located where the environment will either foster corrosion (bathrooms) or false alarms (kitchens). There is some debate as to the wisdom of placing a smoke detector in an unheated garage, for these reasons.

As I read your description, the two areas off the bedroom do not REQUIRE smoke detectors. This is particularily true if the partitions do not extend all the way to the ceiling.
On the other hand, I see no reason NOT to place additional detectors there.

As for the "best bang for the buck," there is a school of thought as to the different types of detectors. While both photoelectric detectors, and ionization-type detectors both pass the exact same UL smoke tests, they do have very different characteristics.
In an area with mists (water vapor) or dust (lint) in the air, it can be argued that the ionization type will have fewer false alarm problems. The ionization type will also respond much quicker to a fire that has a clean, hot flame.
The photoelectric detector tends to respond much quicker to a cold smoke, such as that caused by a smoldering fire, one that has not yet burst into flame. It also is much less likely to be fooled by hot grease in the air- so a photoelectric type is best near kitchens. This type usually costs a little more, and is a little harder to find.

Actual placement in the room should be in an area that has a fair sampling of the rooms' air flowing through it. This means that you should avoid "dead" spots, such as the point where the ceiling meets the wall, as well as staying clear of the fresh air supply vent (heater duct).

#50000 03/23/05 03:49 PM
Joined: Jan 2005
Posts: 354
pdh Offline
I haven't been able to find anything on this in the code. Is there any requirement that smoke detectors be specifically wired at 120 volts AC? Or can they be wired on a low voltage (12 or 24 volts) AC or DC circuit?

#50001 03/23/05 09:46 PM
Joined: Jan 2005
Posts: 5,445
Likes: 3
Cat Servant
The governing code is the general building code- the NEC is silent on the issue.
The smoke alarms can be wired to any power supply that meets the manufacturer's specs. They must have battery back-up. When one sounds, all must sound.
I am not aware of any low-voltage residential smoke alarms. There are such things for commercially montored, central alram systems. I cannot see any reason why an AHJ would not allow you to install such a system in a house.
In that regard, the "special" residential requirements are intended to allow for an affordable system. A central system, with sensors, horns, and strobes, would certainly cost much more than the roll of romex and $5 detectors currently available.

#50002 03/23/05 09:58 PM
Joined: Aug 2003
Posts: 1,374
Lots of threads about smoke detectors (alarms) in the "building codes" forum.

Ryan Jackson,
Salt Lake City

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