Occupancies Within An Occupancy?

[PBWolf]

This may be an obvious question, but I simply cannot find an answer to it. I have a building with an Occupancy of A-3 (it is a library). Within that building, there are multiple storage rooms, a staff room, and mechanical spaces.

My question is do these spaces have their own Occupancy classification? For example, would the storage/mechanical rooms be S-1 and the staff room a B?

These spaces exist to serve the need of the main occupancy (A-3), it seems odd to classify them as something else (S-1, B, etc).

Can anyone point me in the right direction to answer my question? Thanks for your help, long time lurker, first time poster....

 

[Coug Dad]

Welcome to the site. The ancillary occupancies might be small enough to be accessory, or you could classify them for what they are and utilize the non separated approach for mixed occupancies thus avoiding a fire resistive rating between the different occupancies.

 

[PBWolf]

I pursued that avenue, unfortunately, the aggregate area of all of these spaces is larger than 10% of the building area. So separating the occupancies with a fire resistive barrier is an option. However, I am still hung up on the idea that these spaces exist because of the building's main function. It would seem that the occupancy of A-3 would acknowledge that these (secondary) spaces exist to serve the main occupancy, and as such should be included as the main occupancy, not as "accessory".

 

[RJJ]

I agree with CD: One major issue is the S-1 area! Look closely at this because it may need the separation.

 

[Gene Boecker]

PB,

It starts back in Section 302.1 which states that "structures or portions of structures shall be classified with respect to occupancy in one or more of the following groups listed."

Then we move on to 508.1 which tells us that "where a building or portion thereof contains two or more occupancies or uses, the building needs to meet [that] section."

You might try addressing it as a combination of non-separated and accessory. Treat the storage as accessory and the rest as non-separated. If the storage occupancy is the only one that is giving you heartburn use that as the "10%" and let the rest be as they are in a non-separated condition.

How's that work for you?

And. . . welcome to the forum!

 

[peach]

Welcome PB..

If the entire building fits into the height/area for A-3, they are part of the A-3 (what's in the storage areas? probably books... what's on the shelves.. probably books).. there's no increase in hazard... who hangs around in the staff rooms? probably the staff.. again, no increase in hazard..

If they store gasoline or car parts.. then it's a different hazard.

 

[Builder Bob]

Be sure to look at incidential uses, this would allow the building to be classified as A-3. The only time that each space has to be labeled for use is for determination of occupant load and means of egress for those areas.

 

[Brookhaven 58]

One question that I don't think was asked is if the A3 is large enough to require a Fire Sprinkler system (12,000 sq ft or 100 persons). As Builder Bob stated, don't forget Incidental uses, as long as the Storage areas is not larger than the main occupancy. The Incidental Table does not indicate the difference between S1 or S2 just 'Storge rooms'.

 

[peach]

If the entire structure fits into A-3, that's what it is. separate a boiler if necessary.. (they'll chose to separate rare books with some kind of dry chemical system.. if there is such a thing).

There is very little hazard in a library.

 

[FM William Burns]

Peach,

(they'll chose to separate rare books with some kind of dry chemical system.. if there is such a thing)

Clean agent systems with associated detection work extreemly well in facilities wanting to protect documents. (NFPA 2001)

 

[Gene Boecker]

Peach,Clean agent systems with associated detection work extreemly well in facilities wanting to protect documents. (NFPA 2001)

But if you choose that option, the building is not longer "protected throughout with an automatic sprinkler system." It will need a code modification to be legal or else all the sprinkler trade-offs are null and void.

 

[TimNY]

Following along with what peach said.. if the library has an occupancy over 100 it is likely the requirements for the A-3 will encompass all the protections required to cover the other areas as a non-separated use.

 

[FM William Burns]

Suppression Intent?

Good point Gene.



Question: How does one use a recognized and acceptable technology to protect against water damage for such an occurrence taking into account that 904.2 says “shall not be considered alternatives for the purposes of exceptions or reductions allowed by other requirements of this code”



Logically, I could see the "specific" area being totally covered using clean agent and meeting the intent of protection for fire spread. Would this specific type of situation or area have to be a Pre-action or Interlock area since that would still give “total sprinkler coverage”? We don’t sprinkle clean rooms and laboratories do we?



I don’t have the commentary but I believe the intent for sprinkler coverage (i.e. suppression) is met with using the alternative protection method in the specific area. Interesting and I will dive further into it in 903 but have to go now.

 

[Gene Boecker]

Thanks, FM!

We generally either work through a code modification with the local officials or else install a pre-action system with clean agent (double system). The clean agent activates first, that activation also initiates water entry into the pipe. If the clean agent doesn't do it's job, then the sprinkler will fuse and the fire will be suppressed. The trick is in making sure that the dry pre-action system is tight enough to not leak when water enters the line.

"Wet books can be dried. Burned books are just fried."

 

[FM William Burns]

Very nice Gene.