Limited combustible material above suspended ceiling.
Limited combustible material above suspended ceiling.
(OP)
We have an older strip mall project constructed mostly of concrete block, bar joists and metal roof deck.
Upon removal of existing ceiling tiles we found what I would call a small bit of combustible material above the ceiling as shown in this photo.
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The local fire official thinks sprinklers might be required and while I agree it got me to wondering what exactly is the definition of "limited"?
Question to the experts: In your opinion would the amount of cumbustible material you see contribute to a fire threat?
Thanks
Upon removal of existing ceiling tiles we found what I would call a small bit of combustible material above the ceiling as shown in this photo.
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The local fire official thinks sprinklers might be required and while I agree it got me to wondering what exactly is the definition of "limited"?
Question to the experts: In your opinion would the amount of cumbustible material you see contribute to a fire threat?
Thanks





RE: Limited combustible material above suspended ceiling.
is the wood doing any good up there, or can a saws all take care of the problem???
RE: Limited combustible material above suspended ceiling.
I agree seems to be pushing it a bit. I don't see where the diagonal members are doing anything so a saws all would take care of the problem.
I would have to think the vertical members, mostly behind drywall but some exposed, would easily fit the criteria for "limited".
RE: Limited combustible material above suspended ceiling.
HOWEVER......the wood frame concealed space (which is difficult to see behind the gypsum) looks like it might warrant sprinkler protection if the space is continous and has as much wood frame construction as the picture suggests. This area appears to be deeper than a standard wood frame wall. This area would trap heat, allow quick fire propagation and would also be very difficult for fire fighters to extinguish IF the continuous area is significant in size.
I hope this helps.
RE: Limited combustible material above suspended ceiling.
The building is fully sprinklered and the space is currently empty and without a drop ceiling. A FLOATING ceiling is being added, meaning it is a drop ceiling where the edges of the drop ceiling don't meet the walls. Does it require sprinklers above and below or can the existing heads just be dropped through the new drop ceiling?
I've attached an interior elevation showing the ceiling arrangement. Note, the two interior offices you are looking at do not have their own ceiling.
FYI, I'm a mechanical design engineer. We have a sprinkler engineer that we've started outsourcing to, but we've had problems with his interpertation of the code.
Thanks.
RE: Limited combustible material above suspended ceiling.
RE: Limited combustible material above suspended ceiling.
cannot tell what the existing ceiling is made out of, but looks non com.
you do not specify waht the gap will be????
I have required sprinklers above and below, when you have a "cloud effect", also saw one install where there was about 2-3 foot gaps and the solution was a sprinkler head in the gap with a shield, did not agree with the shield option.
RE: Limited combustible material above suspended ceiling.
There are two "cloud" heights: 11' and 12'6" and the deck above is 14', so the gaps are about 3' and 18".
RE: Limited combustible material above suspended ceiling.
1 - Sprinklers at the roof deck above and in the cloud ceilings. A fair amount of work, but seems to be the most conservative and acceptable. Afterall, you can only eliminate sprinklers in 'concealed' non combustible spaces. When you have the perimeter open, the space is no longer concealed. NFPA states that openings such as return air grills do not create a non concealed space. But, the typical RAG is 2'x2' or 4 sq ft. The most I have seen is 2 RAGs together, for a total of 8 sq ft. I figure that if the opening is more than 8 sq ft, then you do not have a concealed space.
2 - Sprinklers in the ceiling and then extending for a length of 15' beyond the open gap. Depending on the size of the room, it may mean fully sprinklered at the deck, or just in a certain area. One job that sticks out where this was done was an office building where there was no ceiling in the halls, but drop ceilings in all of the offices. None of the walls went to the deck. So, sprinklers were placed to protect 15' on both sides of the corridor at the roof deck and in the ceilings at the offices.
3 - Sprinklers placed at the gap at the level of the cloud. Sometimes a pie plate (aka heat collector - but doesn't work) used on the sprinklers at the gap. Based on conversations with FM guys, this is completely useless and a waste of money.
I always recommend #1, but could see the rationale for option 2. Option 3 is a joke IMO. What is your sprinkler guys interpretation?
Travis Mack
MFP Design, LLC
RE: Limited combustible material above suspended ceiling.
RE: Limited combustible material above suspended ceiling.
thank you not an FPE but have never seen where this owuld work, and have been told the sheild can create turbulance and go by the head.
same idea with the gap it can go pass the gap and miss the head, no idea at what width that that could happen, but with a three foot opening kind of big.
RE: Limited combustible material above suspended ceiling.
Good luck!
Travis Mack
MFP Design, LLC