Smoke and heat installed suspended below deck

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JLEECME

Member
This is probably more an NFPA quesiton then NEC but I can't find a NFPA forum with members that I like as much as you guys.
I have an application where the building is constructed of an in floor raceway system so I can't screw into the ceiling deck because it's a raceway for the floor above. I need to install smoke and heat detectors in the elevator equipment room, the only way I can attach to the ceiling deck will result in the fire alarm device being installed about 4 1/2" below the ceiling deck. Do any of you know if it is stated somewhere that a detection device can only be suspended below a flat ceiling a certain amount? I know if mounted on a sidewall it must be a minimum of 4" and a maximum of 12" of from the ceiling. Any insights on this issue or recommendations for a good NFPA 72 forum?
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
I am still searching NFPA 72, I have not found a direct section that addresses this. But there are apps to putting it on the bottom of joists in open frame construction, so maybe there is some leeway. I will keep looking.
 
J

JLEECME

Member
I spoke with the Fire Marshall, he couldn't site a specific code section for the ceiling but referred to the side mountain stipulation of with in 12" of the ceiling and said we could pendant mount to that level below the ceiling.
 
gadfly56

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
JLEECME said:
I spoke with the Fire Marshall, he couldn't site a specific code section for the ceiling but referred to the side mountain stipulation of with in 12" of the ceiling and said we could pendant mount to that level below the ceiling.
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I hope you inperpret that to mean "not MORE than 12" below the ceiling". Otherwise there might be an issues with getting timely activation.

Just so I understand, are you saying that the entire ceiling space is a raceway? You've got a room, say 15' by 10' and it's all a raceway?
 
Weaver Road

Weaver Road

Member
Location
Willington, CT
If I came upon this, I would stop for some research. NFPA 72 says on the ceiling. One thing I would require of the installer/EC would be reconcilliation of the install with the manufacturer's listing/instructions. I would hope to find an answer there so as to move on in the inspection.
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
benaround said:
There are all kinds of epoxys these days to fasten anything to anywhere.
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That was the first thing I thought,,,,,then the second thing I thought is ,,,If they poured the cement so shallow that you can't drill 1" blue and screw somebodys in trouble. The whole buildings gonna fall
 
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