2nd Story with One Exit Access Stair

[architect629]

I'm working on a renovation/change of use of a two story building with a B occupancy, per the 2021 IBC. The first floor is around 5,000 sf and will have 3 exits doors. The second floor is only 500 sf and is served by a single existing exit access stair. I'm slightly confused on whether this 2nd story needs to comply with table 1006.3.4(2) Stories With One Exit or Access to One Exit

Per 1006.3.3, "Each story and occupied roof shall have the minimum number of separate and distinct exits, or access to exits." Two exits required in this case.

The second floor has access to two exits doors on the first floor that comply with exit access travel distance and common path of egress travel. Does that mean this story this complies with 1006.3.3, even though it only has one exit access stair? I can comply with table 1006.3.4(2)., but I would need to construct a small 1 hour rated exit passageway leading to the nearest exit discharge, in order to comply with the reduced exit access travel distance of 75'. I don't want to do that unless it's necessary.

 

[RLGA]

If you read further in Section 1006.3.3, it states, "A single exit or access to a single exit shall be permitted in accordance with Section 1006.3.4."

Unless you want to add a second means of egress from the second story, then, yes, you will need to take advantage of Section 1006.3.4 and Table 1006.3.4(2). However, Table 1006.3.4(2) only allows a 75-foot exit access travel distance (100 feet if sprinklered), so at least one of those three exits on the first story must be within 75 feet (or 100 feet, as applicable) total travel distance (i.e., from the most point in the second story, down the stairs, and to the exit door).

Now, before you get too deep into the weeds on the above, can you consider the "second story" a mezzanine? If so, then the mezzanine is considered a part of the space below and is now subject to Section 1006.2 rather than Section 1006.3.4.

 

[architect629]

Thanks, RGLA! That's what I thought, and unfortunately I can't classify the 2nd story as a mezzanine. I find the language "access to a single exit" confusing. The exit access stair provides access to multiple exits on the first floor. I think it would be clearer of the language read "access to one exit or one exit access stair."

Also, it looks like 100' travel distance for a sprinklered building is only applicable to the first floor, not the 2nd floor.

 

[RLGA]

Why can't you classify it as a mezzanine? Is it less than one-third of the first-story area in which it is located? The mezzanine does not need to be open to the room below if it can use one of the five exceptions (which #1 would probably apply in your situation). If it were a mezzanine, then all you need to be concerned with is the common path of egress travel, which allows you to measure the 75-foot (or 100-foot) travel distance to the bottom of the stairs since there are three exits on the first story (I am assuming that all three or at least two are available to occupants at that point).

Also, it looks like 100' travel distance for a sprinklered building is only applicable to the first floor, not the 2nd floor.

Where did you get that from? Travel distance is the distance required to travel within the exit access from the most remote point within a space to an exit. Exit access stairs are part of the exit access, and the travel distance includes the travel along the stairs. Travel distance is not limited to one story.

 

[Yankee Chronicler]

Also, it looks like 100' travel distance for a sprinklered building is only applicable to the first floor, not the 2nd floor.

How did you arrive at that conclusion?

Travel distance to an exit is travel distance to an exit. It's based on occupancy and use classification, not story. Ditto common path of travel.

As RLGA pointed out, when the egress from a second floor is by an exit access stair rather than an enclosed exit stair, the distances begin at the most remote point on the second floor and the measurement continues across the second floor, down the stair, and across the first floor to the exit door.

 

[architect629]

How did you arrive at that conclusion?

Table 1006.3.4(2)
Footnote b, which allows the travel distance to increase to 100' in sprinkled buildings is only indicated on first floor B, F, & S occupancies. A second floor business occupancy with a single exit is limited to travel distance of 75' per the table below.

 

[RLGA]

You’re correct that the footnote applies to the first floor only. Gives you all the more reason to consider it a mezzanine if you can.