smoke detector 4 " from vaulted ceiling

[Stevenfyeager]

I don't think NEC addresses smoke detectors. But today the elec inspector told me in a vaulted ceiling room, a detector on the wall needs to be within 4 " of the highest ceiling. I thought it was 12 " (I've always heard that because smoke rising causes a curling effect, a wall mounted one needs to be down low enough to catch smoke before it curls away from the corner.) Any thoughts ? Thank you.

 

[hbiss]

The manufacturer's instructions will determine this. See figure 3. I think he has it backwards. You are correct.

https://www.kidde.com/home-safety/en/us/media/Bed_Hall_Living_10_Year_Smokes_low_tcm126-27832.pdf

-Hal

 

[Stevenfyeager]

The manufacturer's instructions will determine this. See figure 3. I think he has it backwards. You are correct.

https://www.kidde.com/home-safety/en/us/media/Bed_Hall_Living_10_Year_Smokes_low_tcm126-27832.pdf

-Hal

Thanks ! I see that. I suppose his " 4" " comes from the 4" space where no detector goes, I understand what he means.

 

[ptonsparky]

Those installation instructions do prove handy on occasion.

 

[Fred B]

Question regarding the posted instructions from Kidde. In the sheet it references in NFPA-72 a requirement for "A row of detectors shal be spaced and located ......" . What is the application for this requirement of a "row"? Never seen in application.

 

[gadfly56]

Question regarding the posted instructions from Kidde. In the sheet it references in NFPA-72 a requirement for "A row of detectors shal be spaced and located ......" . What is the application for this requirement of a "row"? Never seen in application.

For larger spaces (>900 sq ft). You would hardly ever see this in a residential application.

 

[kwired]

Question regarding the posted instructions from Kidde. In the sheet it references in NFPA-72 a requirement for "A row of detectors shal be spaced and located ......" . What is the application for this requirement of a "row"? Never seen in application.

Not an expert on NFPA 72 but I believe a smoke detector is something tied into a fire alarm system where the typical smoke alarm like we often see in dwellings is a different animal to that code and may have some similar requirements but not necessarily the same requirements on use or placement.

 

[Dennis Alwon]

I worked in a home where the first floor bedroom had a 3' by 3' hallway with a return air grill in the ceiling. The next room was the kitchen-- odd arrangement for sure. No place to install a sd and be compliant

 

[NTesla76]

If it is a smoke alarm, I believe they need to be no more 3' away from the peak and no less than 4" from peak. It's in NFPA 72 somewhere.

 

[gadfly56]

If it is a smoke alarm, I believe they need to be at least 3' away from the peak. It's in NFPA 72 somewhere.

Draw a line across the gable end 4" down from the ceiling. Draw another line 36" down from the ceiling. Extend the lines around the sloped ceiling. Place detector(s) between these lines, arranged so the projection of the detector to the floor follows the flat ceiling spacing. This is the first line of detectors closest to the peak.