# Occupant Loads for Corridors with multiple access doors



## EasilyConfused (Mar 2, 2016)

I need to figure out the occupant loads for individual doors for spaces that have access to the corridor.

What I think should be done is to calculate the individual space total occupant loads for the spaces that would typically use that particular corridor as a means of egress, then divide that total occupant load between the doors (say 2 doors) that would access the corridor.

So, say I have 100 occupants that have direct access to a u shaped corridor, I would assign 50 occupants on the left side of the U to one door and 50 to the right side of the U for a total of 100 occupants accessing the corridor but 50 using each of the two doors.

Assuming this is correct, where I start having trouble is figuring out occupant loads per door when it's not as neat an arrangement as the above.

Lets say I have an area that has a bunch of cubicles at one end of a corridor and a large conference room near the middle of the corridor. The corridor has one door at each end.

I'm thinking that the individual door loads would be such that you just anticipate which spaces would use a particular door for egress and you assign those numbers to that individual door, but I'm not sure.

The idea being that one door may have a substantially larger occupant load and the occupant load (say from the conference room in a room at the middle of corridor) may actually be split between the two doors.

In the end however, seems like the total number of occupants that doors are slated to handle should only be required to handle the total number of occupants (say100). Might be split 25 at one door and 75 at the other but total load still needs to add up to 100.

Am I on the right track with this?

Similarly, Lets say I have 3 distinct business areas or business area suites.... potentially even separately leased spaces, I would assign all of those suite space occupant loads to the Exit corridor, but one door pair may be assigned to one suite, another door pair to suite 2 and maybe a portion of suite 3 and the 3rd door only to the remaining portion of occupants for suite 3.


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## cda (Mar 2, 2016)

""""I would assign 50 occupants on the left side of the U to one door and 50 to the right side of the U for a total of 100 occupants accessing the corridor but 50 using each of the two doors.""""

I would  hate to be the 50 assigned to the left side, when there is a fire there!!


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## cda (Mar 2, 2016)

This is a good easy to understand book to get, comes in the 2009 and 2012 IBC

http://www.amazon.fr/Building-Code-Basics-Based-International/dp/1435400674

http://www.contractorresource.com/building-code-basics-commercial/


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## RLGA (Mar 2, 2016)

EasilyConfused: I think you're making it more complicated than it needs to be.  If all spaces use the corridor and the corridor leads to the exits (which it should), then the width of the exit doors from the corridor to the exterior is based on the total occupant load and can be evenly distributed around to all exit doors from the corridor.  It doesn't have to be evenly distributed, but, as you said, as long as the total exit width is provided, then the egress system is in compliance with the requirements.

  ​Using the suite example, the width of the exit access doors from the suites into the corridor will be based on the occupants of each suite. However, don't forget that occupant loads for business areas are based on gross floor area, including the corridor, so the corridor itself will have an occupant load that must be added to the sum of occupants from the suites egressing through the corridor.


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## steveray (Mar 2, 2016)

http://publicecodes.cyberregs.com/icod/ibc/2009f2cc/index.htm

Here is a link to the 2009 commentary online that you can read....


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## EasilyConfused (Mar 2, 2016)

Thanks everyone-

RLGA. I know I'm making it more complicated than it needs to be. Thus the questions. Thanks to your input from this post and prior posts, I really thinking I've gotten over the larger hurdles that have been plaguing me every time I sent down to do this. Reality is, I don't do this everyday (or even every 6 months, so it's real "painful" when I'm tasked to jump back into it. Turns out that my "job description" is somewhat changing and I'll be dealing with this on a more regular basis (hopefully?). Regardless, like I said before your comments are appreciated.... makes me wish I would have got involved here a LONG time ago.

CDA. Thanks for the link to the book. I have an older Francis I Ching "Building Codes Illustrated" that has helped me in a big way at times. Recently ordered the soon to be released 2015 code version. Not familiar with the book you recommend. Any thoughts on that book vs the Ching book?

As an aside, not sure exactly what your comment regarding the 50 occupants per door example I gave means. It's my understanding (could be wrong and maybe misunderstanding where you see the problem) that a 3/0 door with clear width of 2/8 +/- can handle an occupant load of 160 at .2 occupants per inch. Do I have a misunderstanding here?

Steveray. Thanks for the link as well. Recently purchased the 2015 code. Kicking myself for not getting the commentary version. After I got it started looking for a separate commentary but didn't find one. Hate to shell out money for an additional code book with commentary but might. For me really is SOOOOO much easier dealing with the paper version rather than digital. Know anyone who would like a very little worn 2015 Looseleaf IBC at a reduced rate? As an aside, is the paper commentary version a whole lot more cumbersome to deal with?


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## JBI (Mar 2, 2016)

"... at .2 occupants per inch." that's 0.2" per occupant... :eek-new:


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## cda (Mar 2, 2016)

""""CDA. Thanks for the link to the book. I have an older Francis I Ching "Building Codes Illustrated" that has helped me in a big way at times. Recently ordered the soon to be released 2015 code version. Not familiar with the book you recommend. Any thoughts on that book vs the Ching book?

As an aside, not sure exactly what your comment regarding the 50 occupants per door example I gave means. It's my understanding (could be wrong and maybe misunderstanding where you see the problem) that a 3/0 door with clear width of 2/8 +/- can handle an occupant load of 160 at .2 occupants per inch. Do I have a misunderstanding here?"""""

If your question was about 50 assigned this door and 50 assigned another door

Some people think that people will actually exit that way. They will not.

I like all the books I can get.

The one I sent you is a simpler to understand.

,,,,, if you look at the 2009 commentary you can use that as a start to the 2015.

Codes change a little, but the basics do not change that much.


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## EasilyConfused (Mar 2, 2016)

JBI- I think I've got this right....

It's .2" per occupant required door width BUT, it's also .2 occupants per inch of door width.... if I want to figure out the max amount of occupants a door can handle. Correct?

CDA- Simpler to understand than the Ching book or just simpler to understand in general. Are you familiar with the book I'm referring to?


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## cda (Mar 2, 2016)

Great RGLA articles/ info

http://www.specsandcodes.com/articles/default.html#code_corner

Will need to check the library


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## cda (Mar 2, 2016)

You find out how much exit width you need.


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## mtlogcabin (Mar 2, 2016)

> JBI- I think I've got this right....It's .2" per occupant required door width BUT, it's also .2 occupants per inch of door width.... if I want to figure out the max amount of occupants a door can handle. Correct?


Correct 175 people for a 3.0 door with 35 inches of clear width


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## EasilyConfused (Mar 2, 2016)

CDA- what does "you find out how much exit width you need" refer to?

Thanks for the links.

mtlogcabin- thanks for taking the time to give me a sigh of relief. Was concerned I had gotten something major mixed up.

While I'm at it... My understanding (for a hollow metal door and frame) that a 3/0 door actually only has about 32" of clear width (door at 90 degrees). Have you ever run into this being brought up by building officials/planning departments?


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## cda (Mar 2, 2016)

Sorry for short answer you have it, I would say you are saying it backwards.

Figure the occupant load

Than figure minimum exit width required.

http://publicecodes.cyberregs.com/ic...?bu2=undefined

Also check;;;

http://www.specsandcodes.com/articles/code_corner/The%20Code%20Corner%20No.%2022%20-%20Egress%20Width.pdf


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## cda (Mar 2, 2016)

While I'm at it... My understanding (for a hollow metal door and frame) that a 3/0 door actually only has about 32" of clear width (door at 90 degrees). Have you ever run into this being brought up by building officials/planning departments?

If the door does not open all the way.

If they install the wrong size door.

http://publicecodes.cyberregs.com/icod/ibc/2009f2cc/icod_ibc_2009f2cc_10_sec008.htm?bu2=undefined

See the commentary under 1008.1.1


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## JBI (Mar 3, 2016)

> JBI- I think I've got this right....It's .2" per occupant required door width BUT, it's also .2 occupants per inch of door width.... if I want to figure out the max amount of occupants a door can handle. Correct?"
> 
> EasilyConfused, NOT .2 occupants per inch, that would mean 1 occupant for every 5" of door width. it is 0.2" per occupant, so 5 occupants for every inch of door width.
> 
> For new construction the occupant load drives the required egress width, for an existing building the existing egress width could limit the occupant load.


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## cda (Mar 3, 2016)

> JBI- I think I've got this right....It's .2" per occupant required door width BUT, it's also .2 occupants per inch of door width.... if I want to figure out the max amount of occupants a door can handle. Correct?
> 
> CDA- Simpler to understand than the Ching book or just simpler to understand in general. Are you familiar with the book I'm referring to?


""""CDA- Simpler to understand than the Ching book or just simpler to understand in general."""

Yes Ching is in the library.

Would say the Steve Thomas book has less stuff in it maybe by 2/3. But what is in it Steve makes it easier to understand.

Just a suggested book to add.

Plus if you get a chance to set in one of his classes , a good idea.


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## cda (Mar 3, 2016)

EC,

Did we ever ask what state you are in?!!


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## steveray (Mar 3, 2016)

We usually use 32" clear here unless they want to prove otherwise....I have seen up to 177 people claimed....


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## JBI (Mar 3, 2016)

> EC,Did we ever ask what state you are in?!!


Profile says South Carolina...


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## mtlogcabin (Mar 3, 2016)

> CDA- what does "you find out how much exit width you need" refer to?Thanks for the links.
> 
> mtlogcabin- thanks for taking the time to give me a sigh of relief. Was concerned I had gotten something major mixed up.
> 
> While I'm at it... My understanding (for a hollow metal door and frame) that a 3/0 door actually only has about 32" of clear width (door at 90 degrees). Have you ever run into this being brought up by building officials/planning departments?


1008.1.1 states 32 inches is the minimum at 90 degrees. If the door opens 180 degrees I will give them the 35 inches. However rarely will you find an OL of 320 with only 2 exit doors of 3.0 size.


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## cda (Mar 3, 2016)

> Profile says South Carolina...


Go RC Cola and Moonpies!!

Also Cheerwine, for insiders


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## cda (Mar 3, 2016)

http://www.llr.state.sc.us/pol/bcc/

http://www.llr.sc.gov/POL/BCC/index.asp?file=BCCinfo.htm


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## EasilyConfused (Mar 3, 2016)

Thanks Everyone


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