Number of exits not based on cumulative occupant load?

[Brian 2]

2018 IBC 1006.2.1 has added a new exception allowing egress through a vestibule / foyer not to be based on cumulative occupant load. Assuming common path of travel requirements are met, is it the intent of this section to allow virtually an unlimited number of occupants from a "space" to egress through a single exit (access) door from that vestibule / foyer (assuming capacity width is adequate)? See the attached sketch as an example. A "space" can be loosely interpreted; for the below example this could be separate (49 occupant load) office tenants exiting through a common vestibule OR a single tenant with multiple offices exiting through a reception area? does it make a difference?

Thanks!

 

[Francis Vineyard]

Brian 2, the image is not viewable with my browser. However the below interpretation is from Significant Changes to the 2018 IBC may help.

This exception is not a new approach to dealing with cumulative occupant loads but rather restates the language already established in Section 1004.2.1. The revision in Section 1006.2.1 correlates this section with Section 1004.2.1: “Design of egress path capacity shall be based on the cumulative portion of the occupant loads of all rooms, areas or spaces to that point along the path of egress travel.”

Not that the main exit must still accommodate at least one-half of the required egress width when an assembly space has an occupant load greater than 300. Section 1029.2 correlates with the requirements in Section 1006.2.1 by addressing the egress capacity from the lobby rather than recalculation the number of exits from the lobby.

The addition of Footnote q to Table 1006.2.1 correlates with revisions to Table 1017.2 as discussed under that section.

 

[Brian 2]

Heres a direct link to the picture:
https://photos.app.goo.gl/CuyWaAqyUaBv2FSMA

 

[RLGA]

Assuming your diagram is for an entire building, then not quite. Per Table 1006.3.2, each story is required to have two exits when the occupant load is 1 to 500. The building you show does not qualify to be a single-exit building per Table 1006.3.3(2) because the occupant load of the story exceeds 49.

An example showing the intent of Section 1006.2.1 would be as shown below. The lobby has a cumulative occupant load of 196, which would require two exit access doorways per Table 1006.2.1 and as provided in Section 1004.2.1. However, as a lobby, per Section 1006.2.1, subparagraph 1, the number of exits need only be based on the original occupant load of the lobby (49 occupants per the example below), provided the CPET is not greater than 75 feet and the exit doors provide the capacity for the cumulative occupant load.

 

[Brian 2]

Assuming your diagram is for an entire building, then not quite. Per Table 1006.3.2, each story is required to have two exits when the occupant load is 1 to 500. The building you show does not qualify to be a single-exit building per Table 1006.3.3(2) because the occupant load of the story exceeds 49.

An example showing the intent of Section 1006.2.1 would be as shown below. The lobby has a cumulative occupant load of 196, which would require two exit access doorways per Table 1006.2.1 and as provided in Section 1004.2.1. However, as a lobby, per Section 1006.2.1, subparagraph 1, the number of exits need only be based on the original occupant load of the lobby (49 occupants per the example below), provided the CPET is not greater than 75 feet and the exit doors provide the capacity for the cumulative occupant load.
View attachment 3101

The exit access door in my sketch would access a corridor with two remotely located exit stairs. So this is not a single exit story.

 

[RLGA]

The exit access door in my sketch would access a corridor with two remotely located exit stairs. So this is not a single exit story.

I don't think what you're proposing complies with the intent or the actual text of the subparagraph. The subparagraph explicitly states "The number of exits..." Your diagram, if considered a tenant space off a corridor, does not provide an "exit" from the foyer, but just an exit access doorway into a corridor. Thus, the situation you show would not be permitted using this part of Section 1006.2.1.