Smoke detector Location

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RICK NAPIER said:
I don't read it that way. The sections read smoke detectors mounted on the ceiling shall... No where does it say they have to mount on the ceiling, but if you where to mount it on the wall it would have to be 4 to 12 inches from the ceiling on the wall that reaches up to the peak.
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Smoke detector must be within 3' of the highest point of the ceiling. If the ceiling is 12' high than the smoke Detector must be a min 9' off the floor weather it be on the wall or on the slope of the ceiling.
 
Cavie said:
Smoke detector must be within 3' of the highest point of the ceiling. If the ceiling is 12' high than the smoke Detector must be a min 9' off the floor weather it be on the wall or on the slope of the ceiling.
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I you read NFPA 72 11.8.3.2 Peaked Ceilings and 11.8.3.2 Sloped ceilings the both describe how detectors that are mounted on these ceiling shall be located no more than 3" from the peak. These sections do not address wall mounted detectors. Wall mounted detectors are covered in 11.8.3.4.
 
Cavie said:
Smoke detector must be within 3' of the highest point of the ceiling. If the ceiling is 12' high than the smoke Detector must be a min 9' off the floor weather it be on the wall or on the slope of the ceiling.
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<BR><BR>I you read NFPA 72 11.8.3.2 Peaked Ceilings and 11.8.3.2 Sloped ceilings the both describe how detectors that are mounted on these ceiling shall be located no more than 3" from the peak. These sections do not address wall mounted detectors. Wall mounted detectors are covered in 11.8.3.4.
 
RICK NAPIER said:
<BR><BR>I you read NFPA 72 11.8.3.2 Peaked Ceilings and 11.8.3.2 Sloped ceilings the both describe how detectors that are mounted on these ceiling shall be located no more than 3" from the peak. These sections do not address wall mounted detectors. Wall mounted detectors are covered in 11.8.3.4.
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Your missing the point. They must be within Thirtysix inches of the highest point of the ceiling. Period. If that point is on the wall fine. If not, it must be on the slope of the ceiling to a point within Thirtysix inches of the highest point of the ceiling. If you want to go to the highest point than by all means do it. Flat ceilings must be on the ceiling or on the wall 6" below the ceiling.
 
I tend to agree with Cavie on this. Wall mount is allowed but not if the ceiling is more than 3' from the placement of the sd.
 
Cavie said:
Your missing the point. They must be within Thirtysix inches of the highest point of the ceiling. Period. If that point is on the wall fine. If not, it must be on the slope of the ceiling to a point within Thirtysix inches of the highest point of the ceiling. If you want to go to the highest point than by all means do it. Flat ceilings must be on the ceiling or on the wall 6" below the ceiling.
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Where does it say "within Thirtysix inches of the highest point of the ceiling"? The six inches below the ceiling is listed in many not all smoke detector installation instructions and must be followed when it is listed but the NFPA code is 4 inches.
 
I know that our area will not accept it on the wall if there is a vaulted ceiling. The Firex brochure states

AVOIDING DEAD AIR SPACES
?Dead air? spaces may prevent smoke from reaching the Smoke Alarm. To avoid
dead air spaces, follow the installation recommendations below.
On ceilings, install Smoke Alarms as close to the center of the ceiling as possible.
If this is not possible, install the Smoke Alarm at least 4 inches (102 mm) from the
wall or corner.
For wall mounting (if allowed by building codes), the top edge of Smoke Alarms
should be placed between 4 inches (102 mm) and 12 inches (305 mm) from the
wall/ceiling line, below typical ?dead air? spaces.
On a peaked, gabled, or cathedral ceiling, install the first Smoke Alarm within 3
feet (0.9 meters) of the peak of the ceiling, measured horizontally. Additional Smoke
Alarms may be required depending on the length, angle, etc. of the ceiling's slope.
Refer to NFPA 72 for details on requirements for sloped or peaked ceilings.
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Nowhere does the info state that it must be at the highest point but IMO that is where it is meant to be as smoke rises. Putting it on the wall way below ceiling level could be a disaster.
 
Rick NFPA72 states that if the ceiling has more than a 1' in 8' rise then the smoke detector must be mounted at the high end. I do not have the article at this point but that was from a more recent smoke detector by Kiddie.

I also found this on a different website

As stated by the NFPA: "Since smoke and deadly gases rise, alarms should be placed on the ceiling at least 4 inches from the nearest wall, or high on a wall, 4-12 inches from the ceiling. This 4-inch minimum is important to keep alarms out of possible "dead air" spaces, because hot air is turbulent and may bounce so much it misses spots near a surface. Installing alarms near a window, door or fireplace is not recommended because drafts could detour smoke away from the unit. In rooms where the ceiling has an extremely high point, such as in vaulted ceilings, mount the alarm at or near the ceiling's highest point."
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Cavie said:
Your missing the point. They must be within Thirtysix inches of the highest point of the ceiling. Period. If that point is on the wall fine. If not, it must be on the slope of the ceiling to a point within Thirtysix inches of the highest point of the ceiling. If you want to go to the highest point than by all means do it. Flat ceilings must be on the ceiling or on the wall 6" below the ceiling.
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That is the scenario I am asking about. Looks like we still have no agreement as to whether or not that is correct.

Lets throw in a ceiling fan that likely will effect the distribution of smoke? Does NFPA 72 mention anything about that?
 
kwired said:
That is the scenario I am asking about. Looks like we still have no agreement as to whether or not that is correct.

Lets throw in a ceiling fan that likely will effect the distribution of smoke? Does NFPA 72 mention anything about that?
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I believe NFPA 72 does mention it but I also know that the manufacturers instructions state to keep away from fans.
 
Maybe this will help to clear things up.

Here is the section on specific locaions from NFPA 72 (2006,I believe):

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.

What I see a lot os SD's close to the kitchen and right outside bathrooms...
And I was surprised about the 36" from a paddle fan but it makes sense if it's on.


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Thanks Cavie. I worked on a remodel where the design of the house made it impossible to not be in violation on the install of the sd. Bedroom led to a 5' long hall where there was a door to a bathroom and then open to the kitchen. Also in the hall was the cold air return. Fortunately the sd was existing and I just changed it to carbon/smoke. Inspector let it go as there was no other choice and it was existing.
 
Here is somethink from the 2010 NFPA 72

ry%3D480
 
Dennis Alwon said:
Here is somethink from the 2010 NFPA 72

ry%3D480
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The very code sections I was referencing but from the 2007. As you see it tells you where the smoke detector must be when mounted to the ceiling but nothing in these sections require the detector to be mounted on the ceiling. If you mount it on the wall it would need to meet the more restrictive case of 4" to 12" from the top of the ceiling.
 
I had not noted this before but 29.8.3 in 2010 has removed the requirement to be 4" down from the ceiling that was previously found n the 2007 and earlier versions but they retained this requirement for heat detectors.
 
Taken alone I agree but look at post 28. The intent is to have the alarms respond as quickly as possible. That will no be the case on the walls.
 
RICK NAPIER said:
I think that if the detector is on the wall 4" to 12" from the high point in the ceiling it will respond quickly.
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That would depend on the size of the room and the slope of the ceiling. A ceiling that's 1/1 in a room 20' wide might be problematic with a 10' difference between the wall height and peak height.
 
RICK NAPIER said:
I think that if the detector is on the wall 4" to 12" from the high point in the ceiling it will respond quickly.
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Yes, but you were saying it can be on a wall 4-12" down from the ceiling -- we were assuming you meant the low side of a vaulted ceiling. It would have to be up at the high point. That is what I thought what we were discussing. Certainly if 4-12" is within the 36" from the peak that is not an issue-- I thought we stated that earlier.
 
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