# Building "Design" occupant load vs Occupant load



## EasilyConfused (Mar 25, 2016)

Is there a difference between "building design occupant load" and "occupant load"?

I have a mixed use building split equally between A-3 & B occupancies. The A-3 side is assembly in it's entirety. The B side has storage, kitchen, classrooms etc, which all still fall under the B occupancy requirements.

So, I'm thinking that for "Design occupant Load" I would divide entire assembly area by it's factor (15N), divide entire business area by it's factor (100G), then add the results together and get a total design occupant load.

But thinking it's different for calculating actual occupant loads.... which I'd break out the individual use types within the B occupancy, divide by their factors in then add all the loads together to determine actual occupant load of the building.

Is this accurate? Just seems like there is a distinction between these two types of calculations, but not real clear on why "design occupant load" as I'm presenting it here would be useful to a building official. Maybe for initial planning purposes?


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## mark handler (Mar 25, 2016)

I do not understand the rabbit hole you are going down.

The code book has a step by step guide. it is just after the preface in the code "Effective Use of the IBC".


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## RLGA (Mar 25, 2016)

Actually, the phrase used is "design occupant load"--the addition of "building" does not appear (at least not in the 2015 IBC).  "Occupant load" is a defined term, whereas "design occupant load" is described in Section 1004.1 and includes the cumulative occupant loads upon for which the means of egress or a portion thereof is designed.  The definition of "occupant load" indicates it's the number of occupants for which the means of egress is "designed"; so, in essence, there really is no difference and they can be used interchangeably.  Using "design occupant load" is kind of like saying "ATM machine."


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## EasilyConfused (Mar 25, 2016)

Mark Handler- Thanks for pointing me to that section of the code. At first I got excited, then realized that it's really no more than a summary as to what the chapters contain. Not helping me any in this situation, unfortunately.

RLGA- That clears it up for me. Occupant load is occupant load. Would it be correct to say that the only reason for calculating occupant load is to determine egress requirements.... like is alluded to at the beginning of the section 1004? Just had it in my head that there was more to it than that- that the occupant loads had much bigger project implications. Thanks.


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## cda (Mar 25, 2016)

"""""Would  it be correct to say that the only reason for calculating occupant load is to determine egress requirements.""""""

NO

Occupant load also drives other requirements in the building and fire code


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## EasilyConfused (Mar 25, 2016)

OK. Thanks.


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