Smoke detectors in dwelling

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Dennis Alwon

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That is a building code issue not an NEC issue. Every bedroom needs interconnected smokes along with the adjacent hallways. In addition a carbon detector is also needed outside every bedroom area. We use combination smoke/carbon detector. Every floor also needs a smoke detector whether there is a bedroom or not.
 

Dennis Alwon

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I read somewhere, that there is also a requirement that they are not suppose to no more than 30 feet apart.


That pertains to a hall area. For instance if your hall is 25' long and the bedrooms are off that hall then one in the center will cover the area, however if you have a 32' hallway then you may need 2 smokes. This is in the manufacturers instructions
 

jaylectricity

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Massachusetts
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licensed journeyman electrician
As mentioned it's a building code thing. Around here you put a smoke in every bedroom and a carbon monoxide within 10' of any bedroom. Often one CO/Smoke combo in the hallway can be situated to take care of all the bedrooms. Then a CO/Smoke combo at the bottom of every stairwell and one in the attic.
 

Dennis Alwon

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As Jay stated every area may have there own amendments so check with the building code in your area. As Gus told me in TN the CO detector is only need if there is a natural fuel system or a attached garage-- not so in NC and I have no idea about Texas
 

E16

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Iowa
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What locations require a smoke detector in a dwelling?

The IRC has some good information on this.

Section 314 covers Smoke Alarms

Section 315 covers Carbon Monoxide Alarms

This is out of the 2009 IRC hope this helps.
 

cadpoint

Senior Member
Location
Durham, NC
In Residential (I'm not usually in residential)

Isn't there a dead zone on the placement of the detector on a wall to the ceiling above?

On a vertical wall that in fact smoke will not be seen in a wedge of space say
6 to 8 inches where the vertical wall meets the ceiling?

So in fact if a wall has a smoke detector in this wedge, should it be moved to the ceiling?
 

mwm1752

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Location
Aspen, Colo
In Residential (I'm not usually in residential)

Isn't there a dead zone on the placement of the detector on a wall to the ceiling above?

On a vertical wall that in fact smoke will not be seen in a wedge of space say
6 to 8 inches where the vertical wall meets the ceiling?

So in fact if a wall has a smoke detector in this wedge, should it be moved to the ceiling?

Commercial requirements for a fire alarm type system can be reasearched in the International Fire Code for starters. Another good source is the manufacture's installation instructions -- you will have a tough time finding a defined location in commercial buildings that works with all locations as there are many scenario's to work with.
As for to close to walls & ceiling my understanding is that the smoke will roll when it gets to corners which in turn is why you will find a min distance to that corner.
 
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gadfly56

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New Jersey
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Professional Engineer, Fire & Life Safety
In Residential (I'm not usually in residential)

Isn't there a dead zone on the placement of the detector on a wall to the ceiling above?
On a vertical wall that in fact smoke will not be seen in a wedge of space say
6 to 8 inches where the vertical wall meets the ceiling?

So in fact if a wall has a smoke detector in this wedge, should it be moved to the ceiling?

The answer is both yes and no. "Yes", if you're on the 2007 edition of NFPA 72, "No" if you're on 2010 or later. Someone did some actual testing and foud that there really isn't any dead zone.
 

infinity

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New Jersey
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Journeyman Electrician
}} and one in the attic. {{

I thought that it was not recommended to install them in an attic (possibly due to attic temp.? )

I agree this is from first alert:

http://www.firstalert.com/index.php#downloads

LOCATIONS TO AVOID FOR SMOKE ALARMS
For best performance, it is recommended you AVOID installing
Smoke Alarms in these areas:
? Where combustion particles are produced. Combustion particles
form when something burns. Areas to avoid include poorly ventilated
kitchens, garages, and furnace rooms. Keep units at least 20 feet
(6 meters) from the sources of combustion particles (stove, furnace, water heater, space heater) if possible. In areas where a 20-foot
(6 meter) distance is not possible ? in modular, mobile, or smaller homes, for example ? it is recommended the Smoke Alarm be placed as far from these fuel-burning sources as possible. The placement recommendations are intended to keep these Alarms at a reasonable distance from a fuel-burning source, and thus reduce ?unwanted? alarms. Unwanted alarms can occur if a Smoke Alarm is
placed directly next to a fuel-burning source. Ventilate these areas
as much as possible.
? In air streams near kitchens. Air currents can draw cooking smoke into the sensing chamber of a Smoke Alarm near the kitchen.
? In very damp, humid or steamy areas, or directly near bathrooms with showers. Keep units at least 10 feet (3 meters) away from showers, saunas, dishwashers, etc.
? Where the temperatures are regularly below 40? F (4.4? C) or above
100? F (37.8?C), including unheated buildings, outdoor rooms,
porches, or unfinished attics or basements.

? In very dusty, dirty, or greasy areas. Do not install a Smoke Alarm
directly over the stove or range. Keep laundry room Smoke Alarms free of dust or lint.
? 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.
? In insect infested areas. Insects can clog openings to the sensing
chamber and cause unwanted alarms.
? Less than 12 inches (305mm) away from fluorescent lights. Electrical ?noise? can interfere with the sensor.
? In ?dead air? spaces. ?Dead air? spaces may prevent smoke from
reaching the Smoke Alarm.
 

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
You know, I never paid attention to the word "habitable" in regards to the attic. I just went with "every level of the home" which I assumed included the attic.

Thanks for the heads up because that means one less location I need to put in on a job I'm doing.
 

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
You know, I never paid attention to the word "habitable" in regards to the attic. I just went with "every level of the home" which I assumed included the attic.

Thanks for the heads up because that means one less location I need to put in on a job I'm doing.


Some areas around here require the attic to have a smoke if there is permanent stairs and the area can be used as habitable space. IMO, It would be worth , at least, getting the smoke circuit up there for future use so that it will be tied to the rest of the system.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I've used relay module per manufacturer for connection of heat detectors to smoke detector circuit in attics before. Which are OK to install in attics or garages.
 
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infinity

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Location
New Jersey
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I've used relay module per manufacturer for connection of heat detectors to smoke detector circuit in attics before. Which are OK to install in attics or garages.

I once looked for something like that for a job but couldn't find one, have a link?
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
Because the last heat detectors I used with Kidde smoke detectors were simply a dry contact type. Needed the relay module to interface with the signal conductor on interconnected smokes.

Also the heat detector iwire shows has temp threshold of 135*F I would not use this in an attic where temps reach 140+ degrees F.
 
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