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4 exits required - 3 interior exit stairways and 1 exit access stairway provided

hapyhour

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Thank you all for your discussion. I was able to confirm informally with ICC that the horizontal exit will be our solution to provide the compliant number of exits on the 6th floor.
 

cda

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I take existing building.

Will be interesting on how they get a code compliant two hour wall in
 

Tim Mailloux

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At least one stair will be required on each side of the horizontal exit.
He has (3) stairs already so that should not be an issue. Attention will have to paid as to where the horizontal exit is placed and the occupant load on either ride is the wall. he is can split the occupant load 50/50 there will be 500 plus occuants on each side of the horizontal exit, with each side requiring access to 3 exits. One side theoretically would have access to 3 exits (2 exit stairs and the horizontal exit), the other side would only have access to (2) exits (1 exit stair and the horizontal exit.
 

steveray

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But if the HE is connected to the stair, it still does not seem like a gain on number of exits, more like an exit passageway....but most of my HE experience is a FW to a different building....
 

Tim Mailloux

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But if the HE is connected to the stair, it still does not seem like a gain on number of exits, more like an exit passageway....but most of my HE experience is a FW to a different building....
In this case the HE will divide the 6th floor into two separate buildings for the lack of a better description. The occupant load and egress capacity for the population on either side of the HE will be individually analyzed and the HE will serve as one of the required exits for the occupants on both side of the HE. I have used this strategy often in type IA & IB high rise buildings
 

cda

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In this case the HE will divide the 6th floor into two separate buildings for the lack of a better description. The occupant load and egress capacity for the population on either side of the HE will be individually analyzed and the HE will serve as one of the required exits for the occupants on both side of the HE. I have used this strategy often in type IA & IB high rise buildings


How is this solved, if there is only one exit on the 6th??



""""""" Horizontal exit? On the sixth floor? Without a dedicated stair? I need pictures.....
At least one stair will be required on each side of the horizontal exit.""""""""""""""""
 

steveray

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Yeah...I think I have it in my mind now...as long as the HE isn't more than 50% and remoteness and all of that other stuff, I can see it working I just don't really like the "Non-FW" HE concept....I guess with 2hr structure it is not such a big deal....

Although not sure the OP get to use it with an exit access stair...

refuge
areas connected by a horizontal exit shall be provided by
a fire wall complying with Section 706; or by a fire barrier
complying with Section 707 or a horizontal assembly complying
with Section 711, or both. The minimum fire-resistance
rating of the separation shall be 2 hours. Opening
protectives in horizontal exits shall also comply with Section
716. Duct and air transfer openings in a fire wall or fire barrier
that serves as a horizontal exit shall also comply with
Section 717. The horizontal exit separation shall extend vertically
through all levels of the building unless floor assemblies
have a fire-resistance rating of not less than 2 hours with no
unprotected openings.
 

Tim Mailloux

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How is this solved, if there is only one exit on the 6th??




At least one stair will be required on each side of the horizontal exit.""""""""""""""""

He has (3) interior exit stairs on the 6th floor, but he needs 4 due to an occupant load over 1000 people.
 

Tim Mailloux

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Hartford CT
refuge
areas connected by a horizontal exit shall be provided by
a fire wall complying with Section 706; or by a fire barrier
complying with Section 707 or a horizontal assembly complying
with Section 711, or both. The minimum fire-resistance
rating of the separation shall be 2 hours. Opening
protectives in horizontal exits shall also comply with Section
716. Duct and air transfer openings in a fire wall or fire barrier
that serves as a horizontal exit shall also comply with
Section 717. The horizontal exit separation shall extend vertically
through all levels of the building unless floor assemblies
have a fire-resistance rating of not less than 2 hours with no
unprotected openings.

does this mean that you cannot have both the HE and the exit access stair on the 6th floor? Wouldnt the exit access stair qualify as an unprotected opening?
 

RLGA

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He has (3) stairs already so that should not be an issue. Attention will have to paid as to where the horizontal exit is placed and the occupant load on either ride is the wall. he is can split the occupant load 50/50 there will be 500 plus occuants on each side of the horizontal exit, with each side requiring access to 3 exits. One side theoretically would have access to 3 exits (2 exit stairs and the horizontal exit), the other side would only have access to (2) exits (1 exit stair and the horizontal exit.
Yes, I know, but if all three are on one side of the horizontal exit, then you still have a problem--thus my comment that there has to be at least one stairway accessible from each refuge area.

Your description of dividing the occupant load 50/50 with 501+ occupants in each refuge area will not work. As you indicated, at 501+ occupants you need access to three exits. With three stairways, there will be two within one refuge area and one in the other refuge area. The refuge area with only one stairway has access to only two exits: the stairway and the horizontal exit (you cannot use one exit to access another exit). Therefore, the refuge area with the single stairway must have an occupant load that is 500 or less; the other refuge area can have 501 to 1000 occupants since it has access to three exits.

EDIT: It is possible to have one of the stairways straddle the horizontal exit and be accessible from both refuge areas, thus giving each refuge area access to three exits.
 

Tim Mailloux

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Hartford CT
Your description of dividing the occupant load 50/50 with 501+ occupants in each refuge area will not work. As you indicated, at 501+ occupants you need access to three exits. With three stairways, there will be two within one refuge area and one in the other refuge area. The refuge area with only one stairway has access to only two exits: the stairway and the horizontal exit (you cannot use one exit to access another exit). Therefore, the refuge area with the single stairway must have an occupant load that is 500 or less; the other refuge area can have 501 to 1000 occupants since it has access to three exits.

EDIT: It is possible to have one of the stairways straddle the horizontal exit and be accessible from both refuge areas, thus giving each refuge area access to three exits.

I agree, my 50/50 comment was meant to demonstrate a situation where the HE wouldnt not solve the problem and atention will have to be paid as to where to HE occurs and the occupant load on each side of the HE and location of exits studied.
 

RLGA

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Yeah...I think I have it in my mind now...as long as the HE isn't more than 50% and remoteness and all of that other stuff, I can see it working I just don't really like the "Non-FW" HE concept....I guess with 2hr structure it is not such a big deal....

Although not sure the OP get to use it with an exit access stair...

refuge
areas connected by a horizontal exit shall be provided by
a fire wall complying with Section 706; or by a fire barrier
complying with Section 707 or a horizontal assembly complying
with Section 711, or both. The minimum fire-resistance
rating of the separation shall be 2 hours. Opening
protectives in horizontal exits shall also comply with Section
716. Duct and air transfer openings in a fire wall or fire barrier
that serves as a horizontal exit shall also comply with
Section 717. The horizontal exit separation shall extend vertically
through all levels of the building unless floor assemblies
have a fire-resistance rating of not less than 2 hours with no
unprotected openings.
steveray, you are correct. If they provide an exit access stairway it cannot be open--it must have an enclosure that is equal to the floor/ceiling assembly, which is 2-hours.
 

Tim Mailloux

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Messages
339
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Hartford CT
steveray, you are correct. If they provide an exit access stairway it cannot be open--it must have an enclosure that is equal to the floor/ceiling assembly, which is 2-hours.

This is from the code commentary with regards to unprotected opening between floors:
The second option is to utilize fire barriers that are not aligned vertically (i.e., a combination of fire barriers and horizontal assemblies), but then the floor must have a 2-hour fire-resistance rating and no unprotected openings are permitted between any two refuge areas. The supporting construction would also have to be a minimum of 2 hours.

The underlined text "no unprotected openings are permitted between any two refuge areas" kind of muddies the waters for me. The way this reads to me, is that unprotected openings are not allowednly if the floor below or above is also separated with a horizontal exit creating refuge area. Or am I missing something?
 

steveray

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Code is "more safe" than commentary so I will go with that....I think of it like a circle with one blocked quadrant....if you can still bypass and go 360 degrees, no bueno....
 

Tim Mailloux

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Messages
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Hartford CT
Code is "more safe" than commentary so I will go with that....I think of it like a circle with one blocked quadrant....if you can still bypass and go 360 degrees, no bueno....

I was wondering if the floor above has no HE, is that entire floor considered a refuge area?
 
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