• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Can an exit serve two buildings and be a separate building in and of itself?

ewenme

ewenme

Sawhorse
Joined
Oct 27, 2009
Messages
306
Location
Troy, ID
A developer and his engineer and architect are seeking to build an 18-plex apartment building: 3 stories, 6 units per floor. The original design has one exit per floor, which I say can't happen. IBC Section 1021 requires two exits from stories with more than four dwelling units. Six is greater than four, therefore two exits are required. The engineer comes back with a new proposal: what if we make it two buildings [with the required two-hour fire wall on the zero lot line] and make the exit a separate building between the two apartment buildings [now requiring only one exit per building] and enclose the exit within two-hour constructed walls? He is thinking that going from the balcony into the fire-rated exit "building" should be allowed, since the code doesn't dis-allow it. Has anyone dealt with someone wanting to construct an exit enclosure as a separate building and allow it to be used by two separate buildings on the same lot? The building footprint is at the maximum allowed by zoning to meet setbacks and height.

Can you say 'frustration?' Any and all comments are appreciated. R-2 Occupancy, Type V-A construction with sprinklers.

Thanks, in advance. Carol
 
1021 is 4 dwelling units AND 50 ft of travel distance.

What is the travel distance from the most remote room in the most remote dwelling?
 
That is part of the problem: The building is 25 feet deep, 120 feet wide and three stories high. Worst case scenario: 25' to the front door, which means you are about 60 feet from the common path of egress [to the top of the stairs]. I still don't believe it's my job to show him how to meet the code requirements...it's his job to show me how he can meet the code requirements. I just don't buy the 'exit as a separate building' theory that he's come up with. IMHO.
 
If the designer meets the requirements for fire walls I don't see a problem. Travel distance would stop at the exit enclosure which could help this design.
 
The design has two exits, one exit being a horizontal exit (parapet above roof?) to this "second" building with a vertical exit enclosure at one end of the corridor, and the second being at the other end of the corridor?
 
The 50 feet is total travel distance to an exit. Just give him the code sections. As kilitact states the travel distance stops at the exit enclosure and it is what it is if it meets code.

Worst case scenario: 25' to the front door, which means you are about 60 feet from the common path of egress [to the top of the stairs].
Click to expand...
BTW common path of travel is included in the overall maximum 50 ft length. From what you describe the travel distance will not meet code with one exit.
 
In addition to 50' travel distance the 125' common path egress travel distance would run to the exit discharge at the lowest level of the exit enclosure wouldn't it? Also what is the occupant load? 1 per 200 gross. If greater than 10 then per 1015 2 exits. The balcony has to conform to 1019 as well does it not?
 
imhotep said:
Also what is the occupant load? 1 per 200 gross. If greater than 10 then per 1015 2 exits. QUOTE]1015 and 1021 have exceptions to allow one exit if the building is sprinkled and has occ load of 20 or less.
Click to expand...
 
Thank you. Where do egress balconies per 1019 fit in? Assume 4 occupants per unit (800 gross square feet) then egress balcony occupant load is 16 < 20 one exit permitted with sprinkling?
 
ewenme, the separate building wording is coming from 503.1 (2009 ed). This brings up a great point. When buildings are considered separate by 503.1, do they require their own independent means of egress? In the private sector, I have seen this applied this way; but, have also seen it allowed to egress across "buildings" (in terms of 503.1). In my opinion, the building you describe should be fine since the fire wall separations are being provided as long as the layout allows them to meet the 50 feet. 120 minus 10 for stair /2 = 55 already....not looking like it with the current layout.
 
Last edited by a moderator:
imhotep said:
Thank you. Where do egress balconies per 1019 fit in? Assume 4 occupants per unit (800 gross square feet) then egress balcony occupant load is 16 < 20 one exit permitted with sprinkling?
Click to expand...
1019 could have an impact it is hard to say without plans (dead ends would worry me). I do however think Papio is right, once they hit the balcony they have gone through a horizontal exit.
 
Common path of travel for this occupancy would be 125', travel distance would be 250'. The travel and common path of travel distance stops at the vertical enclosure wich taks you to either the discharge or a horizontal exit. Balcony's need to meet Section 1019.

Hello RJJ, was lurking for awhile then I thought I just had to throw my two cents in.
 
Once you are on the balcony [outside the individual dwelling unit] you are 'outside' in fresh air. Why would you want to 'go back into the buidling' to exit? IF the exit is a separate building, as suggested by the engineer, is that OK? Everyone's comments are appreciated. I believe if the 'exit as a separate building' is allowed, and the 'two' buildings with 3 units per floor are considered separate buildings by virtue of the 2-hour rated commone walls with the 'exit building' then the travel distance of 50' would go away. UP to four units can have one exit per floor. Anyone agree with that?
 
Horizontal exit?

But even with the two hour wall, as originally proposed you still have to provide required exiting for each building

Also are there going to be utilities and sprinkler pipe running between these TWO buildings???
 
Last edited by a moderator:
cda said:
Horizontal exit?But even with the two hour wall, as originally proposed you still have to provide required exiting for each building
Click to expand...
The travel distances reset once you pass from the dwelling unit through (horizontal exit 1016.1) the two hour wall to the balcony. At that point the balcony has to follow the rules of a corridor, and has to meet the requirements for common path of egress travel 1014.3 exc. #4 125'
 
I read the original post wrong

I guess if they can achieve two separate buildings that meet code, along with the shared exiting, different
 
ewenme said:
Once you are on the balcony [outside the individual dwelling unit] you are 'outside' in fresh air. Why would you want to 'go back into the buidling' to exit? IF the exit is a separate building, as suggested by the engineer, is that OK? Everyone's comments are appreciated. I believe if the 'exit as a separate building' is allowed, and the 'two' buildings with 3 units per floor are considered separate buildings by virtue of the 2-hour rated commone walls with the 'exit building' then the travel distance of 50' would go away. UP to four units can have one exit per floor. Anyone agree with that?
Click to expand...
A sketch would be helpful. However, I think the concept of horizontal exits is applicable, in general.

Keep in mind that to create buildings a fire walls must be built - which requires quite a bit more than the typical stair enclosure, including structural independence.

And the 50 foot travel distance is actual and based on the furnished space from the most remote point.
 
1025.1 Horizontal exits.

Horizontal exits serving as an exit in a means of egress system shall comply with the requirements of this section. A horizontal exit shall not serve as the only exit from a portion of a building, and where two or more exits are required, not more than one-half of the total number of exits or total exit width shall be horizontal exits .

You cannot have just a horizontal exit serving one space

Common path of travel is not part of the equation on this scenario it is maximum 50 feet of total travel before you reach a protected egress path. It could be a exit passageway or a verticle exit enclosure.
 
so the question is will it be cheaper to make it two buildings with one exit, or one building with two exits????????????????????
 
Ah good point (A horizontal exit shall not serve as the only exit from a portion of a building).

So you are saying that a sprinkled and properly designed 1019 egress balcony does not constitute a protected MOE.
 
I think what I'm reading (and it looks like cda sees this too), has nothing to do with a horizontal exit. It's a fire wall, dividing it into two buildings. Because it is two buildings, per the new Table 1021 (2009 IBC) only one exit from each building is required. And that one exit is provided to each building in the form of a single vertical exit enclosure. Is that correct ewenme?

Edit:

Here's why you tell them it won't work: if they are dividing it into two buildings, then you have an assumed lot line. A fire wall at a lot line can have no openings.
 
Last edited by a moderator:
And that one exit is provided to each building in the form of a single vertical exit enclosure.
Click to expand...
That's the way I see it to

25' to the front door, which means you are about 60 feet from the common path of egress [to the top of the stairs].
Click to expand...
and the travel distance to that single exit currently exceeds the 50 foot maximum allowable.
 
I agree that a horizontal exit does not apply at the "exit" of the dwelling unit.

As far as using a separate building to exit from (503.1 defined separate building) imagine this scenario. You have a rectangular multi-story building with two stairwell exits at each of the long ends. For whatever reason there are two fire walls to break the building up IAW 503.1 (formerly known as area separation walls from the old UBC) into three separate sections. You now have three separate buildings who are utilizing the same egress system. Occupants from the center section have to exit through another "building" to get out from the upper levels. And occupants from the two end sections have to egress through other "buildings" to utilize their second exit. In my opinion, a separate egress system would not need to be provided from each of the "buildings" and the occupants should be allowed to egress through other "buildings" to get out.

The short point from this is yes, I think they should be allowed to use the other "building" to egress from.
 
You must log in or register to reply here.
Top