Stage Sprinklers

[JKJeremy]

I have an existing theater fully sprinkled with a large stage, in which the stage is being modified and is partially over a basement area. The modifications to the stage will include mainly building different levels, steps, platforms etc. onto the existing stage surface which is a combination of plywood and MDF sandwich layers on an aluminum grid support system. We intend to build the new levels/steps etc. using cold formed metal studs and joists with a similar plywood/MDF sandwich floor. The basement area under the stage is sprinkled and a small portion of the existing stage (not over the basement) is a concealed area over the main floor concrete slab approximately 3'-4" in height is currently sprinkled. My question is do concealed areas under stages require sprinklers if the rest of the building is fully sprinkled and you are using non-combustible supporting structure. The only mention that I see in the code (410.6) references not requiring sprinklers under stages that are less than 4' in height and are utilized for storage of tables and chairs if you provide 5/8 type x gyp. separating that area from all other areas. Where does it require sprinklers under stages in the first place and if it does not then this section would only seem to apply if the concealed space is being used for storage, which we are not doing with our modifications.

 

[cda]

Would call to what edition of nfpa 13 is adopted in that ahj

Not into ibc but can you have combustible construction in there in the first place??

 

[JKJeremy]

it's an existing building with combustible construction within it. i can't speak as to whether it's allowed to be there in the first place since i don't have original construction drawings. I believe the code requires that the floor material be constructed of similar materials as those required for the building floor system. at any rate i'm just curious as to whether you are required to sprinkle concealed spaces under stages and if so does this 410.6 section exception negate that requirement if those areas aren't being used for storage even if they are less than 4'.

 

[Dr. J]

If the building is required to be sprinklered in accordance with NFPA 13, then all combustible concealed spaces need to be sprinklered. There are a some exceptions, and you should review NFPA 13 to see if you can make any of those work, but I doubt it. The main exceptions are for very small spaces, such as between 6" joists, by stuffing the space with non-combustible insulation, or if the combustible material is only FRTW.

From NFPA 13: 8.15.1.1 Concealed Spaces Requiring Sprinkler Protection. All concealed spaces enclosed wholly or partly by exposed combustible construction shall be protected by sprinklers except in concealed spaces where sprinklers are not required to be installed by 8.15.1.2.1 through 8.15.1.2.16 and 8.15.6.

…

8.15.1.2.7 Concealed spaces entirely filled with noncombustible insulation shall not require sprinkler protection.

…

8.15.1.2.11 Concealed spaces in which the exposed materials are constructed entirely of fire-retardant treated wood as defined by NFPA 703, Standard for Fire Retardant–Treated Wood and Fire-Retardant Coatings for Building Materials, shall not require sprinkler protection.

 

[Dr. J]

The IBC reference is to require sprinklers specifically for the stage in an otherwise unsprinklered building.

 

[JKJeremy]

Ok that makes sense now, thanks. I'll take a closer look at that NFPA section now that I have a place to start. However if I'm understanding this requirement it only applies to concealed combustible spaces, so if I'm using noncombustible framing (cold form studs/joists) and was to substitute the first layer of the plywood floor sandwich with FRT plywood with the subsequent layers being standard plywood this would in effect create a noncombustible concealed space not requiring a sprinkler or any additional treatment correct?

additionally, if the space is in fact sprinkled then I can use standard combustible wood framing if desired?

 

[cda]

If non com is used and it meets requirements for non com out of nfpa 13 than yes no sprinklers required

Cannot answer because should there be combustible material in the building to begin with

 

[JKJeremy]

If non com is used and it meets requirements for non com out of nfpa 13 than yes no sprinklers requiredCannot answer because should there be combustible material in the building to begin with

and i can't really answer that either at this point, other than to say if it's not supposed to be there then this building has much bigger issues than just the stage which are not a part of this scope of work.

 

[north star]

= = $

JKJeremy,

Since you are altering the existing stage, do you also plan to build a compliant

MOE that is ADA / Accessible compliant [ i.e. - a lift or ramp ] ?

$ = =

 

[peach]

I can't find my NFPA 13 right now, but I think there is another exception for interstitial spaces <18".