Delay of Sprinkler Operation in a Floating Ceiling
Delay of Sprinkler Operation in a Floating Ceiling
(OP)
We have a room that has a floating ACT ceiling with a 5" gap around the edge of the ceiling and the wall. We have sprinklers in the ceiling tiles only as we veiwed the space above as a concealed noncombustible space. The fire marshal has now come back and requested that the architect "close or seal off" the space where the 5" reveal is around the perimeter of the room is due to the fact that, in his words, "it will delay the activation of the sprinkler heads." None of the sprinklers are installed within 36" - 60" of the edge of the ceiling grid.
My question is, is there any code section that requires this reveal to be closed up? The only thing I can find in NFPA talks about when sprinklers are required above the ceiling due to the area above the ACT being open.
Thanks!
My question is, is there any code section that requires this reveal to be closed up? The only thing I can find in NFPA talks about when sprinklers are required above the ceiling due to the area above the ACT being open.
Thanks!





RE: Delay of Sprinkler Operation in a Floating Ceiling
I'm still trying to wrap my head around how the sprinklers in a essentially sealed noncombustible space will operate and how sealing of the reveal will help accelerate their response.
RE: Delay of Sprinkler Operation in a Floating Ceiling
We have come across this situation many times. Essentially, it comes down to the issue where the space above the ceiling is concealed or non-concealed. If it is non-concealed, then you need sprinklers above it. Honestly, I have never seen an AHJ accept that a 5" gap around the perimeter is a concealed space. We put sprinklers at the deck, then treat the clouds as obstructions over 48" wide and put sprinklers in/below them as needed.
Unfortunately, I don't believe you will find anything in any building code or NFPA standard that will support your position. The installing contractor will have to put sprinklers above the clouds or the builder will have to seal off that gap.
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: Delay of Sprinkler Operation in a Floating Ceiling
And the reason ceiling tile cannot be put in the opening??