I'm working on a public storage facility and i have a concern with the design.The design is a wet based sprinkler system,
however there is a cavity that seems unprotected attached are sketches
Ok not to clear on what area you are talking about. If you could redraw and make it clearer.
So I will give you two answers.
It appears the ceiling in the corridor, as you walk, is tight all the way across. If so no problem there. But if you walk into one of the storage units, and the is an open area, that you can see, above the corridor, either sprinklers are needed in that "void" area, or a solid vertical wall to keep heat and smoke from getting into it.
If not open, as if you are standing in a storage unit, and the storage unit ceiling is tight,
And there is no combustible construction, which it looks like all metal, than no sprinklers are required.
So which one of the above is closer???
I normally do not look for validation, just trying to clarify the answer.
OHHH I am not an engineer, so you can discount my reply if you want, and I cannot do math.
Lawrence K. Woods
LKW Engineering, LLC
28 Swan Ct.
Jersey City, NJ 07305
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All I can say at this time is that all spaces in the building must be sprinklered to comply with NFPA 13. However, even concealed spaces must be sprinklered unless the exemptions in Section 8.15 of NFPA 13 apply.
Your sketch did not tell me much. Your question needs a lot of discovery of the facts before a meaningful answer can be found.
I can not speculate what the local building codes and regulations are for sprinklers for the storage facility.
Pulic Storage Doc's
the link above are all the documents for the Public Storage facility, There are suspended cloud ceilings @ 8'-0" in the corridors. the storage partitions are 9'-0" H and the concrete deck is 10'-3". there are concealed sprinklers 15'-0" on center. however the corridor is 5'-0" wide the cloud ceiling is 3'-0" wide center of the corridor there is a 1'-0" open wide void on both sides of the ceiling to the deck i have sprinkler coverage in the adjacent storage units and the is coverage in the corridor.
my question is the void. please advise
Senior Plumbing/Fire Prevention Engineer
Jarmel Kizel Architects and Engineers, Inc.
42 Okner Parkway
Livingston , NJ 07039
305-331-1637 - M
973-994-9669 Ext. 162
Not sure your question???
If you look at 3160, it appears there are sprinklers below the cloud, and also above.
Thanks for getting back with me.
I think I understand the void you are talking about. The suspended architectural feature that covers the mechanical equipment is a "cloud ceiling" by architectural definitions and Section 184.108.40.206 of the NFPA 13 standards.
Looking at your photos the upright sprinklers appear to be within 12 inches of the concrete deck that must be used to cover the corridor to ensure that the sprinklers operate once the hot gas layer develops at the ceiling. The concrete deck is a ceiling as defined by Section 3.3.5 of NFPA 13. The installation standards of those sprinklers also requires sprinklers to be located is such a way that items within 18 inches vertically of the sprinkler do not prevent the spray pattern from developing and that horizontal obstructions more than 18 Inches below the sprinkler are not so large that the water spray cannot reach large areas of the floor. Also, the air ducts and mechanical equipment may also obstruct the sprinkler's spray pattern that were installed within 12 inches of the concrete deck. The photos show the installation of sprinklers under the suspended architectural feature so all the areas of the corridor floor are covered per NFPA 13.
In the parameters of this construction, sprinklers will be required both above and below the cloud. The cloud is located more than 12 inches below the upper ceiling to allow mechanical equipment to be located between the upper and lower ceiling, which necessitates sprinklers above the cloud ceiling. The clouds are large enough to create obstructions that prevent the spray pattern from reaching the floor. The presence of these obstructions requires that sprinklers be placed below the cloud as well, so that there is complete coverage.
The omission of sprinklers in a cloud ceiling are in accordance with Section 8.15.24. It does not address omission of sprinklers above the cloud ceiling for installation of air ducts and mechanical equipment.
With all that being said, the question as I see it now becomes: Do the locations of the sprinklers above the cloud provide adequate coverage required for the mechanical equipment and obstructions above cloud ceiling
NFPA 13 requires the sprinklers above the cloud to be positioned and located for satisfactory performance and distribution according with Section 220.127.116.11.2 of the standard for obstructions to sprinkler discharge pattern development. Section 18.104.22.168 has the requirements for positioning sprinklers to avoid obstructions to discharge that applies to the sprinklers above the cloud known as the "Three Times Rule". However, if the design was for ordinary hazards, Section 22.214.171.124.1.4 does have exemptions for structural members. If the cross section drawing of the corridor depicts the installation of fixtures above the cloud, I would say sprinklers need to installed on the opposing sides of the obstructions to completely cover the area and the void you mentioned.
Field observation of each sprinkler above the cloud should be conducted to verify the "Three Times Rule" to obstructions have been met.
Excerpts from the 2016 NFPA 13 for standard upright and pendent sprinklers.
You meet NFPA 13 as per the drawings and pictures posted.
Is there a question I am missing?
Fair enough. Glad to see you have a crystal ball. Field inspections may just disagree with you.
Took me a while to figure out how to view the sprinkler plans you attached.
The sprinkler plans you posted did not shown the sprinklers for the cloud ceiling in the aisles. Only pendent heads were shown.
The sectional drawing provided on the first post appears to shown a suspended ceiling fully extending for wall to wall, not a cloud ceiling as the photos show. The sprinkler plans do coincide to that.
No cross sections were on the sprinkler plans to show the cloud ceilings. Was the cloud ceiling an after thought and field modifications were made?
To me if these are the only documents you have for inspection, the modified plans for the ceiling would need AHJ approval before completing the final inspection.
BTW if the ceiling cavity on this drawing was build as shown the ceiling cavity requires sprinklers when the space is contiguous and open to the storage units.
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