# Concealed space



## D a v e W (Jan 13, 2010)

Ok let see if I can write this correctly. Commercial masonry building, entry land with stairs that go down 5 risers, second set of stairs to the left head up to a mezzanine. Stairs and landing wood construction with *no 1 hour requirements*. All plywood 5/8". Stairs to mezz is walled from floor to roof all drywall is 5/8 X GWB, other side of stair is masonry. Non-accessible concealed area created under all stairs and landing protected by again 5/8 X GWB on one side with masonry on the other.

FMO had the contractor cut an opening to get mezz and required the inside of this to be drywalled according to NFPA 13. FMO says both sides of a non-accessible concealed area must be drywalled. I think he is misunderstanding this requirement in NFPA 13 or I am as well as the plans examiner missing something as just do not understand his thinking.

Please shed light (not fire) on this so I can see clearer. Thanks much everyone


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## cda (Jan 14, 2010)

Re: Concealed space

any chance fmo sited a section of nfpa 13 for the requirement????

 that is why they call it a combustible concealed space

has fmo done this other projects??


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## D a v e W (Jan 14, 2010)

Re: Concealed space

Yes he did, and it is a sprinkled building. No he has never dione this before, however he did say that he has missed this on numerous projects. It sounds like he took a class and is miss appling it now. Red is what he is citing. And the FMO is a friend of mine, just seems way out there with this. One last last thing, there is nothing running through this concealed area, no plumbing, mechanical, electrical, did I mention nothing?

8.1.1*   The requirements for spacing, location, and position of sprinklers shall be based on the following principles: 

(1) Sprinklers shall be installed throughout the premises.

(2) Sprinklers shall be located so as not to exceed the maximum protection area per sprinkler.

(3) Sprinklers shall be positioned and located so as to provide satisfactory performance with respect to activation time and distribution.

(4) Sprinklers shall be permitted to be omitted from areas specifically allowed by this standard.

(5) When sprinklers are specifically tested and test results demonstrate that deviations from clearance requirements to structural members do not impair the ability of the sprinkler to control or suppress a fire, their positioning and locating in accordance with the test results shall be permitted.

(6) Clearance between sprinklers and ceilings exceeding the maximums specified in this standard shall be permitted, provided that tests or calculations demonstrate comparable sensitivity and performance of the sprinklers to those installed in conformance with these sections.

(7) Furniture, such as portable wardrobe units, cabinets, trophy cases, and similar features not intended for occupancy, does not require sprinklers to be installed in them. This type of feature shall be permitted to be attached to the finished structure.

8.15.1.2* Concealed Spaces Not Requiring Sprinkler Protection.   

8.15.1.2.1*   Concealed spaces of noncombustible and limited-combustible construction with minimal combustible loading having no access shall not require sprinkler protection. The space shall be considered a concealed space even with small openings such as those used as return air for a plenum. (For additional information on combustible loading, see A.8.15.1.2.1.)

8.15.1.2.10   Concealed spaces where rigid materials are used and the exposed surfaces have a flame spread index of 25 or less, and the materials have been demonstrated not to propagate fire when tested in accordance with NFPA 255, Standard Method of Test of Surface Burning Characteristics of Building Materials, extended for an additional 20 minutes in the form in which they are installed, shall not require sprinkler protection.


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## FM William Burns (Jan 14, 2010)

Re: Concealed space



> Non-accessible concealed area created under all stairs and landing protected by again 5/8 X GWB on one side with masonry on the other.


*(Complies with 8.15.1.2.10) and the “no-access” (Complies with 8.15.1.2.1)*



> FMO had the contractor cut an opening to get mezz and required the inside of this to be drywalled according to NFPA 13


*(Don’t understand the access panel if the mezzanine is accessed by the “stair to the left”) :? *


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## cda (Jan 14, 2010)

Re: Concealed space

sorry without being there hard for me to visualize, but

there may be other sections of concealed space that applies, and with out seeing it, but sounds like no sprinklers are required.

Usualy I put it back on the sprinkler company to prove me wrong, whihc they do every so often.

Is the sprinkler company saying not needed also???  if so sounds like a wrong call by fm


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## D a v e W (Jan 15, 2010)

Re: Concealed space

FM..... sorry didn't realize what you said in the second part. Then of course the dim light bulb recieved a very small induction of power :lol: DFM made them open area under stairs for mezz and drywall the inside of the space :roll:  Thanks for for yours and cda's response, kinda thought this might not be right.


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## mtlogcabin (Jan 15, 2010)

Re: Concealed space



> limited-combustible construction


I don't have access to NFPA 13 at home but if memory is correct there is some wording about drywall in that definition in the NFPA


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## peach (Jan 16, 2010)

Re: Concealed space

oh.... he took a *class...*

How often does THIS cause problems?


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## beach (Jan 20, 2010)

Re: Concealed space

?


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