# Corridor question



## cda (Jul 29, 2016)

Have seen this posted twice recently, using different scenarios.

Is there a code section that supports it???



"""50/50 split in the capacity, with 1/2 going one direction and the other 1/2 going the other direction,""""


As in if the occupant load of the building is say 58, does the code support splitting that number so say a rated corridor is not needed.
Because 29 go one way and 29 the other??

Just wonder how you herd people so they split evenly???


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## steveray (Jul 29, 2016)

If 30 people enter the corridor, I don't care which way they turn...


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## cda (Jul 29, 2016)

steveray said:


> If 30 people enter the corridor, I don't care which way they turn...




So than if you were dealing with a non sprinkled building
And had a corridor 


You would require it to be rated??


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## steveray (Jul 29, 2016)

YES....It's not like we are doing timed release or something like that where we can guarantee that there will only be 29 at a time in it. If 2 15 person rooms enter it, regardless of which direction they might be likely to head, rate it or sprinkler it...Let's not confuse or blend CPET and OL.


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## cda (Jul 29, 2016)

Thanks just trying to see where the code support is for:::



""50/50 split in the capacity, with 1/2 going one direction and the other 1/2 going the other direction,""""


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## Builder Bob (Jul 29, 2016)

None - it is strictly a matter of interpretation of how to apply "corridor serving 30 " , I know from NFPA Fire and Life Safety Plan Review Class this was presented back in the 80's as the methodology for applying the "serving" quotation of the code.
The SBCCI Commentary also supported this interpretation back in the day and gradually was morphed out of commentaries and written interpretations from the Code Making Authority.


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## cda (Jul 29, 2016)

Builder Bob said:


> None - it is strictly a matter of interpretation of how to apply "corridor serving 30 " , I know from NFPA Fire and Life Safety Plan Review Class this was presented back in the 80's as the methodology for applying the "serving" quotation of the code.
> The SBCCI Commentary also supported this interpretation back in the day and gradually was morphed out of commentaries and written interpretations from the Code Making Authority.




Thanks

Always wonder how you herd people one way and some the other.

Especially when the clown is chasing after  them with a horn.


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## JPohling (Jul 29, 2016)

So if you have two required exits and you are calculating exit width for your various components you do not use 1/2 of the occupant load?  of course you do!


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## cda (Jul 29, 2016)

JPohling said:


> So if you have two required exits and you are calculating exit width for your various components you do not use 1/2 of the occupant load?  of course you do!



Yes when applying required exit width and number of required exits.

But does that extend to " occupant load served by corridor "    ????

Where is the code to back it


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## JPohling (Jul 29, 2016)

wish I could find it, but same logic prevails..............how do you herd only half thru each component?  why is that allowed?


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## ADAguy (Aug 1, 2016)

What happens in a panic? The herd follows the lead cow off the cliff.


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## FM William Burns (Aug 17, 2016)

Not if the lead cow is calm and people in the queue are not subjected to additional signs of fire like heat or smoke obscuration.  There are some great Human Behavior studies available from the late Guylene Proulx and Dr. John L Bryan.


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## cda (Aug 17, 2016)

I like Jake Pauls studies


http://www.securityinfowatch.com/article/10592478/an-introduction-to-stadium-and-arena-egress-design


http://www.bldguse.com/Welcome.html


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## JBI (Aug 17, 2016)

Corridor width is not necessarily a function of 'emergency' evacuation. It may be that everyone enters and exits through the front door during the normal course of occupancy. The second means of egress or second exit is often primarily or predominantly for 'emergency' situations.


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## steveray (Aug 17, 2016)

A corridor with 2 doors is different than just a corridor...a corridor with 30 people in it is just that, can you say that 15 go each way so that your doors work. YES, but you can't say the corridor only has an OL of 15 because there are 2 doors to chose from with 30 people....


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## cda (Aug 17, 2016)

JBI said:


> Corridor width is not necessarily a function of 'emergency' evacuation. It may be that everyone enters and exits through the front door during the normal course of occupancy. The second means of egress or second exit is often primarily or predominantly for 'emergency' situations.





Where does it say

"emergency exit" in the IBC

OR

"Fire Exit"

I hate those terms being used, and one of these days by golly, I am going to introduce a code section to ban them!!!!





I would say any additional exit width required, is for minimum to get the "occupant load" served by the Egress system out of the building.

As in Rhode Island Night club???


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## mtlogcabin (Aug 17, 2016)

cda said:


> Yes when applying required exit width and number of required exits.
> 
> But does that extend to " occupant load served by corridor "    ????
> 
> Where is the code to back it



1005.5. Distribution of egress capacity.
Where more than one exit, or access to more than one exit, is required, the means of egress shall be configured such that the loss of any one exit, or access to one exit, shall not reduce the available capacity to less than 50 percent of the required capacity.

1004.1.1 Cumulative occupant loads.
Where the path of egress travel includes intervening rooms, areas or spaces, cumulative occupant loads shall be determined in accordance with this section.

1004.1.1.1 Intervening spaces.
Where occupants egress from one room, area or space through another, the design occupant load shall be based on the cumulative occupant loads of all rooms, areas or spaces to that point along the path of egress travel.

CORRIDOR. An enclosed exit access component that defines and provides a path of egress travel.

Basically a corridor is nothing more than an intervening space that must be traversed to reach an exit. The above sections are where you go to back up the reasons for determining occupant loads for a corridor and then requiring exits sized upon 1/2 the occupant load in the corridor going each direction


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## cda (Aug 17, 2016)

mtlogcabin said:


> 1005.5. Distribution of egress capacity.
> Where more than one exit, or access to more than one exit, is required, the means of egress shall be configured such that the loss of any one exit, or access to one exit, shall not reduce the available capacity to less than 50 percent of the required capacity.
> 
> 1004.1.1 Cumulative occupant loads.
> ...




Where does it say 1/2 occupant load going each way??


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## mtlogcabin (Aug 17, 2016)

It is a given mathematical equation when the second exit has to accommodate 50% or 1/2 of the OL
How else can you meet 1005.5. where there are only 2 exits provided?


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## JBI (Aug 17, 2016)

cda said:


> Where does it say
> 
> "emergency exit" in the IBC
> 
> ...



And I didn't use those terms, so I'm not sure why you quoted me... unless it was to misquote me?


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## cda (Aug 17, 2016)

JBI said:


> And I didn't use those terms, so I'm not sure why you quoted me... unless it was to misquote me?




That was the other MT log,

Sorry


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## cda (Aug 17, 2016)

mtlogcabin said:


> It is a given mathematical equation when the second exit has to accommodate 50% or 1/2 of the OL
> How else can you meet 1005.5. where there are only 2 exits provided?





Where does it say 1/2 occupant load going each way??

Agree with your statement there, but that is just a performance item.


If you had four required exits, you would have to accommodate 50 % through them. and the width would be spread out.


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## sergoodo (Aug 17, 2016)

Yes, if you can meet  2012 IBC, 1021.2 exception #1 - show the areas of the 50/50 split and the associated single exit required.

*
1021.2 Exits from stories. *
Two exits, or exit access stairways or ramps providing access to exits, from any story or occupied roof shall be provided where one of the following conditions exists:
1. The occupant load or number of dwelling units exceeds one of the values in Table 1021.2(1) or 1021.2(2).
2. The exit access travel distance exceeds that specified in Table 1021.2(1) or 1021.2(2) as determined in accordance with the provisions of Section 1016.1.
3. Helistop landing areas located on buildings or structures shall be provided with two exits, or exit access stairways or ramps providing access to exits.
*
Exceptions:
1. Rooms, areas and spaces complying with Section 1015.1 with exits that discharge directly to the exterior at the level of exit discharge, are permitted to have one exit.*


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## cda (Aug 17, 2016)

My bottom line I think is

If you have a non sprinkled building

A corridor

An occupant load of 30 using that corridor

You cannot say 15 will go one way and 15 will go another way 

There for I do Not  have to rate the corridor 

You do.

It serves 30


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## sergoodo (Aug 17, 2016)

cda said:


> My bottom line I think is
> 
> If you have a non sprinkled building
> 
> ...




Agreed...sort of, but if you have a single story 2 exit required building that has a waiting room with an occupancy of 30 with exit directly to the exterior, I interpret you would not add 30 occupants to the corridor to access the 2nd bldg exit.  This interpretation is in line with the the exception to classrooms with doors to exterior where in a building that requires 2 exits you can say the kids will go this way...


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## mtlogcabin (Aug 17, 2016)

In a non-sprinklered building the rating of the corridor is not determined by how many exits there are from the corridor or the building. It is determined by how many people will be using the corridor. If 2 exits are required you have to add 1/2 the waiting room OL to the corridor they will be forced to use. If the accumulative number exceeds 30 then it has to be rated


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## FM William Burns (Aug 31, 2016)

cda said:


> I like Jake Pauls studies
> 
> 
> http://www.securityinfowatch.com/article/10592478/an-introduction-to-stadium-and-arena-egress-design
> ...



I sit on the MOE TC with my esteemed colleague Jake and love working with him and others.


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## cda (Aug 31, 2016)

FM William Burns said:


> I sit on the MOE TC with my esteemed colleague Jake and love working with him and others.




I was trying to find some of his study videos and post them


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## JBI (Sep 1, 2016)

To be clear... the Code does not require any occupant to go in any particular direction to any particular exit.
What the code requires is that where there are more than one exit, the loss of any one exit will not reduce the total capacity by more than 50%. 
That does not require half the occupants to go one way or the other, it simply ensures that if any one exit is compromised that the remaining exit(s) will be able to handle the occupants egressing from the space.


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## cda (Sep 1, 2016)

JBI said:


> To be clear... the Code does not require any occupant to go in any particular direction to any particular exit.
> What the code requires is that where there are more than one exit, the loss of any one exit will not reduce the total capacity by more than 50%.
> That does not require half the occupants to go one way or the other, it simply ensures that if any one exit is compromised that the remaining exit(s) will be able to handle the occupants egressing from the space.




Best explanation during this political year I have heard.


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## Chadchester1 (Sep 8, 2016)

Can someone please explain to me the fire door requirements in a sprinkled building or where I can find that information? I'm looking for the actual code telling me what the doors should be rated in a particular rated wall and how it breaks down.


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## cda (Sep 8, 2016)

Chadchester1 said:


> Can someone please explain to me the fire door requirements in a sprinkled building or where I can find that information? I'm looking for the actual code telling me what the doors should be rated in a particular rated wall and how it breaks down.




Which edition and building code do you want referenced


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## cda (Sep 8, 2016)

Chadchester1 said:


> Can someone please explain to me the fire door requirements in a sprinkled building or where I can find that information? I'm looking for the actual code telling me what the doors should be rated in a particular rated wall and how it breaks down.




The answer can vary

Normally worse case scenario 20 minute door.

Where corridors are not rated, can have any type door to no door at all


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## mtlogcabin (Sep 8, 2016)

Table 716.5  2012 IBC

Sprinkled or not the requirements are the same


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## cda (Sep 8, 2016)

mtlogcabin said:


> Table 716.5  2012 IBC
> 
> Sprinkled or not the requirements are the same



How's that??


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## steveray (Sep 9, 2016)

The wall rating may change based on sprinklers but the opening protective rating is driven off of the wall rating...And I believe all rated walls need rated OP....At least 20 min.


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## my250r11 (Sep 9, 2016)

2009 IBC Table 715.4


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## FM William Burns (Sep 9, 2016)

cda said:


> I like Jake Pauls studies
> 
> 
> http://www.securityinfowatch.com/article/10592478/an-introduction-to-stadium-and-arena-egress-design
> ...



I know a guy that sits on the MOE committee with Jake.  He and this guy dined together in June and had great conversations on human behavior, those mentioned and stairs of course.


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