Storage occupancy: separation from other occupancies, and S-1 vs S-2

[pipesnpumps]

There is something I don't understand with the IBC 2006, Table 508.3.3. This is kind of related to NFPA codes, so not out of line to post here..

An example:
A sprinklered building that is an IBC business occupancy (B) has a storage area that is >3,000 sq ft, and it is chosen to have the storage area "separated" per IBC definition with a fire barrier.

The storage to be separated has combustible materials, so therefore it is group "S-1" (moderate hazard, aka combustible) storage. Table 508.3.3 shows that S-1 to B fire barrier is No separation required.

But comma however, if the storage had been chose as S-2 (low hazard aka non-combustible) storage, it would require a 1 hour fire barrier for S-2 to B..

NFPA 101 would be 1 hour for separated occupancies.

What the heck, over?

 

[stookeyfpe]

The B occupancy presents a greater fire risk than the Group S-2 occupancy. As a result, a minimum one-hour fire-resistive separation is required.

In the case of a Group B, F-1 and S-1 occupancies, the IBC treats them equally because they are believed to have equivalent fuel loads. As a result, no fire-resistive separation is required.

 

[pipesnpumps]

Appreciate your input Stookey. That is precisely what is baffling to me.. S-2 by its very definition contains non-combustible commodities (with minor amounts of paper packaging allowed).

S-1 is combustible commodities, but as you pointed out is apparently considered to have a lower fuel loading that S-2 non-combustibles, and therefore less of a risk..

I understand "thats just the way it was written", but that scenario makes absolutely no sense to me. It is almost like they got S-1 and S-2 reversed in that table.

Essentially as I read it the code says you don't need a B to S separation fire barrier for polyurethane etc, but if you are storing relatively innocous metal cans, oh no. thats gonna require a fire barrier. Just doesn't compute.

 

[stookeyfpe]

Actually, look at the other way. Say you have a warehouse filled with bags of ice (Group S-2) and adjacent to it is a Group B occupancy with modular furniture offices, server rooms and the like. The Group B occupancy presents a bigger fuel load than the S-2 so the IBC requires fire-resistive separation to prevent fire extension into the less hazardous area.

In my happy joy joy code world, the classification of Group S occupancies would be based on:

a) Is high piled combustible storage present, and
b) What is the commodity classification

Maybe in the future I'll have the opportunity to fix it but for now, it is what it is.

 

[LCREP]

Less hazard?

Per NFPA 13 the Group B occupancy with modular furniture offices, server rooms Light Hazard .10/1500= 150 gpm plus 100 hose =250 gpm

Class 1 commodity on racks to 12' Ord Grp 1.15/1500= 225 gpm plus 250 gpm hose= 475 gpm

Class 1 commodity on racks to 20' .21/2000= 420 gpm plus 500 gpm hose = 920 gpm

Stookey Yea u got to fix this!

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Fire Sprinklers Save Firefighters’ Lives Too!

 

[LCREP]

oops the 20' racks design is for pallet storage on the floor.

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Fire Sprinklers Save Firefighters’ Lives Too!