Horizontal Exit

[hallro]

Hi all,

Running into some code interpretation challenges and would appreciate your input.

Project Overview:

• 5-story, 19-unit apartment building
• 4 levels of R-2 above 1 level of enclosed carport (U)
• Fully sprinklered (NFPA 13)
• Occupied rooftop terrace
• 2022 California Building Code

Issue:
Per CBC/CFC 1009.2.1, standby power for the elevator is required unless a 2-hour horizontal exit is provided on every floor (excluding the exit discharge level), assuming full sprinklers.

Since the roof is occupied but can’t feasibly include a horizontal exit, does this disqualify the exemption entirely? Or can the exemption still apply to the floors below, thereby avoiding the need for standby power?

I’ve attached a PDF of the plans. Would love any suggestions on whether a horizontal exit can be added with minimal project impact—or if standby power is ultimately unavoidable here.

Thanks in advance for your help!

 

[Yankee Chronicler]

Your plans don't show the roof level. And where's the firewall? I don't see anything on those plans that looks at all like a firewall.

As to the roof -- the model IBC allows exit access travel to include one story of vertical travel. This means if you can meet the maximum exit access travel distance from anywhere on the roof to an exit, you should be able to use the horizontal exit on the upper enclosed story as an exit and still satisfy egress requirements. Does California retain the provisions allowing exit access travel to include exit access stairs?

Not sure if that would resolve the issue anyway.

 

[TheCommish]

I don't think the first story enclosed carport is a u-occupancy it's a parking garage

 

[Yankee Chronicler]

As to the roof -- the model IBC allows exit access travel to include one story of vertical travel. This means if you can meet the maximum exit access travel distance from anywhere on the roof to an exit, you should be able to use the horizontal exit on the upper enclosed story as an exit and still satisfy egress requirements. Does California retain the provisions allowing exit access travel to include exit access stairs?

Not sure if that would resolve the issue anyway.

I just looked up California BC 1009.2.1. Based on that, treating egress from the roof to the fifth floor as exit access rather than exit doesn't resolve the issue. It looks like you need to provide stand-by power for the elevator.

 

[steveray]

Your plans don't show the roof level. And where's the firewall? I don't see anything on those plans that looks at all like a firewall.

You do not need a FW for an HE...Usually what we see and it should sort of look like a FW unless you have 2 hour floors.....

 

[Tim Mailloux]

You do not need a FW for an HE...Usually what we see and it should sort of look like a FW unless you have 2 hour floors.....

View attachment 15790

a 2 hr rated Fire Barrier would need to be support by 2 rated structure.

 

[steveray]

a 2 hr rated Fire Barrier would need to be support by 2 rated structure.

Correct

sort of look like a FW unless you have 2 hour floors.....

 

[Tim Mailloux]

standby power for the elevator is going to be much less expensive than constructing the fire wall or fire barriers needed for the horizontal exit.

 

[hallro]

Your plans don't show the roof level. And where's the firewall? I don't see anything on those plans that looks at all like a firewall.

As to the roof -- the model IBC allows exit access travel to include one story of vertical travel. This means if you can meet the maximum exit access travel distance from anywhere on the roof to an exit, you should be able to use the horizontal exit on the upper enclosed story as an exit and still satisfy egress requirements. Does California retain the provisions allowing exit access travel to include exit access stairs?

Not sure if that would resolve the issue anyway.

Correct—haven’t explored the 2-hour fire barrier option yet. Just curious if anyone has seen it successfully implemented with exterior egress balconies. Given the limited space, it seems unlikely without revising the layout significantly. We could potentially fit a 6' wide double door along the egress balcony, but even then, it likely wouldn’t meet the horizontal exit requirements.

I just looked up California BC 1009.2.1. Based on that, treating egress from the roof to the fifth floor as exit access rather than exit doesn't resolve the issue. It looks like you need to provide stand-by power for the elevator.

AHJ confirmed and has responded:
"Section 1009.2.1 is admittedly not well written. The reference to “occupied roof” was added late in the code change process to ensure elevator access was provided as an accessible means of egress for rooftop occupancies, just as it is for each accessible story. However, the exception language wasn’t updated accordingly, which creates a conflict.

As you noted, a horizontal exit isn’t practical—or meaningful—for an open-to-sky roof terrace. Yet the code, as written, still requires it to qualify for the exception. In our view, this is a flaw in the code. For fully sprinklered buildings, the occupied roof should be exempt from the horizontal exit requirement in Section 1009.2.1.

This issue is reportedly being addressed, at least in part, in the upcoming IBC 2027, with further clarification expected in IBC 2030. We’ll see how it evolves."