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stories / separation of uses

H

Howard

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May 15, 2018
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7
Location
Oklahoma City, OK
New to this forum, almost got lost reading through all the posts. I do have a question.
IBC 2009
Type IIB construction
4 story building
Full NFPA 13 provided
M use on first floor & B use on second/third/fourth floors.
M use max height, with fire suppression increase gets you 3 stories.
Would a horizontal separation be required between the M & B uses, to allow the M use in a 4 story building?
 
Welcome, and no, a rated horizontal assembly is not required, since Table 508.4 does not require an occupancy separation between a Group M and a Group B occupancy.
 
Table 508.4 is where I stopped & assumed it was ok. BO is saying M use is not permitted in 4 story building, without separation, per table 503
 
You can ask the nice BO to wall you through why not allowed,

And than see if he agrees with the items posted here.
 
Thank you!
His statement is that table 503 gives M use, IIB, with NPFA 13 a max of 3 stories. Therefore it cannot be in the building without a horizontal separation.
 
Howard said:
Thank you!
His statement is that table 503 gives M use, IIB, with NPFA 13 a max of 3 stories. Therefore it cannot be in the building without a horizontal separation.
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He's wrong. Ask him this, "If a separation is required, what is the required rating and where does it say that in the code?" He won't be able to answer that.

No separation is required, however, the Group M cannot be located on the 4th story--that is what Tables 503 and 508.4 indicate.
 
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Howard said:
He points to table 707.3.9 for the rating, 2 hour between M & B uses.
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Table 707.3.9 is for fire areas and not occupancy separation. Fire areas are used in Chapter 9 to determine sprinkler requirements--nothing else.
 
So what you are saying is:??? Use the separated occupancies strategy (2012, 508.4) for the two classifications, which allows the individual occupancy to comply with t503 (508.4.3) as long as the more restrictive classification does not exceed the allowable level from t503, even though there is no separation requirement. Never considered that.
 
Sifu said:
So what you are saying is:??? Use the separated occupancies strategy (2012, 508.4) for the two classifications, which allows the individual occupancy to comply with t503 (508.4.3) as long as the more restrictive classification does not exceed the allowable level from t503, even though there is no separation requirement. Never considered that.
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That is correct. The separated occupancies method is used, and ,per Section 508.4.4, the occupancies are separated in accordance with Table 508.4 (i.e., no separation required).
 
RLGA said:
That is correct. The separated occupancies method is used, and ,per Section 508.4.4, the occupancies are separated in accordance with Table 508.4 (i.e., no separation required).
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Agree on the no seperation,,

But can you have a IIB M on fourth floor??
 
Thanks RLGA. You should write one of your code corner articles on that. (I turn to them often to help me understand these things)
 
I am not an ICC member. The BO did change their requirement for separation. In the commentary they give an example to this very thing, using F-1 & B in a scenario, that changed their minds. Thanks
 
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