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S-1, S-2, and B separations

earshavewalls

Bronze Member
Joined
Oct 21, 2009
Messages
77
Location
Southern California
I think I'll bring this one up again. I've had people try to explain this before and forgot the reasoning (perhaps because it didn't make sense to me), but here it is anyway.....

Why is it that the code (IBC and CBC) allows no separation between an S-1 (moderate hazard storage) and a B (office) but requires separation between an S-2 (low hazard storage) and a B? (Same is true with F-1 and F-2)

I am aware of the differences in Table 503 and see how this could have SOME effect, but I still am not certain of the reasoning. I have an architect asking me this question now and I would like to provide him with a proper response, and would like one myself, to be honest.

Maybe I slept through the class on this, but I just can't remember the reasoning on the issue.

Help?
 
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The IBC Codes allows buildings to be designed as seperated or non-seperated. Everyone assumes uses must be seperated but that is not correct. The designer makes the decision as to which approach he wishes. Plans review only verifies. Chapter 5, Sec 508.3.2 covers non-seperated uses.
 
In the B/S-2 scenario, you are protecting the S-2 from the B, as the B is more likely to have a fire due to fuel loading and the presence of people. In the B/S-1 scenario, the risks are seen as similar so there is no need to protect one from the other. If you lose the S-1 designation and get into H land, the separation reappears and you are protecting the B from the H.

That's the theory, anyway. I've grown to hate the seperate designations for S occupancies. Todays S-2 is tomorrows S-1 with a simple change in tenant or business model.
 
Permitguy is exactly right, with regard to the logic that went into this change - I know, I was there, and I didn't necessarily agree with it, but what can you do?

S-2 is considered a LOWER hazard than B, so separation is required (to protect S-2 from B). S-1 and B are considered equal hazard levels, therefore no separation required.
 
pg and VP hit the nail on the head... including their disagreement with the theory. I like separations. I wish we separated more than we do. Compartmentation is good. JMHO
 
I have an architect asking me this question now and I would like to provide him with a proper response, and would like one myself, to be honest.
Excellent answers for you to use with the architect

Todays S-2 is tomorrows S-1 with a simple change in tenant or business model.
Now help him to convince his client to go the extra mile and seperate all S-1 & S-2 occupancies so there is fexibility and versitility for the future.
 
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