Single exit question

[cda]

Say

B occupancy

Not sprinkled

Third floor

Meets cpet and occupant load for a single exit under 1015 Ibc 2009

Nothing else would require a second exit???

Any single tenant trade offs????

 

[steveray]

Stair is rated enclosure?....1018.2 Table in my code limits to 2 stories, 30 occ, and 75 ft for B

 

[north star]

+ / -

Table 1021.1, `09 IBC ?

- / +

 

[cda]

Ok well that does answer my question

Thanks

 

[RLGA]

North Star nailed it.

I get so many clients thinking that Table 1015.1 allows them one exit on a story...I have to point out to them it is for "Spaces" only, not stories, and then direct them to Section 1021.

 

[AegisFPE]

Perhaps the 3rd floor could be considered a mezzanine, but the maximum occupant load of 29 persons should still be applicable for the total of the second floor and its mezzanine.

Could a stair be added from the second floor to the first floor, such that a portion of the second floor could be considered as a mezzanine to the first floor? This would reduce the occupant load of the second floor, but would also reduce its area for determining the allowable area for a mezzanine above the second floor.

 

[cda]

Well the real question because of no sprinklers was do they have to rate a new corridor

One exception not to is a single exit only requirement but since that does not apply, cannot use it

 

[bbelhumeur]

North Star nailed it. I get so many clients thinking that Table 1015.1 allows them one exit on a story...I have to point out to them it is for "Spaces" only, not stories, and then direct them to Section 1021.

Could you elaborate on this? 1021.1 (5) seems to allow any space that complies with Section 1015.1 a single exit. Note that this is indicating that a single exit, not an exit access doorway, is permitted. No limitation is put on the size of this space (other than CPOT and travel distance). What difference does it make whether the space takes up the entire story or not?

For example in the original poster's example, would a single exit be permitted if the space he describes was only part of a larger story, although separate from it? If the answer is still no, could you give an example of where 1012.1 (5) would come into play?

Thanks...I really can't get my head around this.

 

[RLGA]

1021.1 (5) does apply if the space opens directly to the exterior and on the level of exit discharge (typically ground level). But it does not apply when the space is on the second or higher story.

 

[bbelhumeur]

1021.1 (5) does apply if the space opens directly to the exterior and on the level of exit discharge (typically ground level). But it does not apply when the space is on the second or higher story.

When I read 1021.1 (5) it says only that the the "exits...discharge directly to the exterior at the level of exit discharge" which I took to imply that the spaces might not be on the level of exit discharge. In other words, a stairway that is an exit enclosure may connect the space to the exterior at the level of exit discharge.

I promise you I'm not trying to be dim. I just can't see why it wouldn't say that the spaces had to be on the level of exit discharge if that is the case.

 

[bbelhumeur]

As opposed to a space on a upper level whose single exit discharged into, say, a lobby.

 

[RLGA]

Welcome to the gray area of the code. I see your point and you could probably argue that with the building official. There is intent and then there is what it actually states.

Your point is that the entire space at the upper story exits directly to an exit stairway enclosure (no intervening spaces or corridors), which then discharges at the level of exit discharge. I think the key words in Exception 5 is at the beginning: "Within a story..." I believe this means that the story still requires the number of exits per Table 1021.1, but any one space can have the one exit if it meets the criteria of the exception. The gray area is in regard to an entire story that consists of one space.

Per the Commentary, it states the following:

"One of the main concerns has been that vertical travel takes longer than horizontal travel in emergency exiting situations. However, if the single exit space can exit directly to the exterior rather than into an interior corridor, this provides a higher level of safety. This is the reasoning behind Exception 5."



I know commentary isn't code, but the above gives the impression that the intent of Exception 5 does not include stairs.

 

[bbelhumeur]

Thanks, I don't have access to the commentary, so that seems helpful. I guess I wonder what the point of Exception 5 would be if it did not include spaces on levels other than the level of exit discharge. By this I mean Table 1015.1 is essentially the same as Table 1021.2 (regarding the first floor). In order to satisfy 1021.1 (5) you need to comply with the entire Section 1015.1 including CPOT and travel distance, so it is in a sense more restrictive than 1021.2. In other words, it seems that 1021.2 already would allow single exits for those situations you describe (spaces on the level of exit discharge exiting directly to the exterior, that also comply with Section 1015.1). It doesn't seem like an exception to anything in that case.

I agree, though, that the commentary suggests reading it in the way that you are.

 

[kilitact]

If the space, story has an exit that discharges directly to the exterior at the level of exit discharge one exit is all thats required. This would work for the third story

 

[mtlogcabin]

you need to comply with the entire Section 1015.1 including CPOT and travel distance, so it is in a sense more restrictive than 1021.2.

Not correct

1021.2 is more restrictive because you are limited to a maximum travel distance to reach an exit.

1021.1 restricts CPOT distance where you can choose between 2 exits and your maximum travel distance is limited by Table 1016.1.

a stairway that is an exit enclosure may connect the space to the exterior at the level of exit discharge.

I agree because the travel distance ends when you leave the exit access and enter the protected exit.

Note the commentary quoted above refers to an interior corridor, the requirements for a corridor construction are not even close to the requires for an exit passageway or verticle exit enclosure and that is why a corridor is considered part of the exit access.