Sprinklers in a "floating" ceiling

[coarts]

If you have a decorative "floating" ceiling below the main ceiling that is open around the edges, you need heads in the lower ceiling since it is more than 4 foot wide. However, when do you need to have heads above it also? If the lower ceiling is only say 12" below the main ceiling [all non-combustible] would you leave the heads out above it? Suppose it was 2 or 3 feet below, would the lower heads be sufficient or is it a possibility a fire above it would occur between the ceilings. If there was only 6" space it would be very impractical to install heads. Does the code address this? Thanks

 

[cdafd]

to many what if's


if over 4 feet with normal head and does not meet the egg crate provision, I require sprinklers above and below.

Your other what if's have to be a case by case depending on size of cloud, and how close to the deck.

would apply the four foot rule

if you have Chili's in your area a good example

 

[MaInspector]

If the ceiling is open around the edges, then you are not creating a non-combustable concealed space but a obstruction insted. Therefore the upper head may not be left out.

 

[TravisMack]

I typically draw the line when the deflector is <= 12" from the deck. If the floating ceiling is only 8" below the deck, then I typically just put heads in the lower ceiling provided it can cover all of the floor. If the lower ceiling causes the deflector to be 13" below the deck, then I go with heads above and below.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com