Horizontal Exit

[ElArch]

I have a 4 story type VA apartment building. I separated the building to two buildings by an area separation wall: building A and Building B. Building A has two stairs, building B has one stair. I calculated the exit access travel distance without considering the door on the fire wall. For example, the 229' (in green color) in building B travel through the door at fire separation door to stair in building A. All travel distances are all within 250'.

The QC in my office said that building B has 85 occupancy load. Building B needs 2 exits. One is stair #3, one is the horizontal exit (the door in fire wall). When calculating travel distance in building B, I should stop at the horizontal exit. And he said that we need horizontal exit because there is no emergency generator.

He also said that I can show travel distance as what I did without emergency generator. But I need to add standpipe and hose cabinet and show refuge area next to that door (the horizontal exit).

My understanding is that the separating building A and building B is only for fire purpose. It is not related to exit calculations since all distances are all less than 250'. So the door in fire wall is not a horizontal exit. I don't need standpipe and cabinet next to that door.

Also I am not using elevator as an exit, so I don't need emergency generator.

Please let me know if I need consider that door as a horizontal exit and if I need emergency generator. Thanks!

 

[Yankee Chronicler]

You started a discussion about this same building and the same question in March. Your questions have been answered multiple times. Why start a new discussion of the same question now?

W

Post in thread 'Do the two stairs in the top and right need be accessible to exit level from the first floor directly?'

Jul 23, 2025

I hope I can reach you for the horizontal exit again.

In your image you are pointing to the door between Building A and Building B and ask, “Is this a horizontal exit?”

I guess you could make it a horizontal exit, but I can’t think of why you’d want to. You don’t need a horizontal exit between Building A and Building B, from Building B you can get to your second means of egress (Stair 1) within the 250’ exit access travel distance in Table 1017.2, you also confirm that in your title block.

Why is it that you guys think you need a horizontal exit?

[07/24 edit: see answer to...

• walker.t

• 

And this building does not fall under the IRC, so the Residential Code area is not the appropriate area for this discussion.

 

[walker.t]

Why is it that you guys think you need a horizontal exit?

Looks like you created this new thread as the answer to my question in your first thread.

Please let me know if I need consider that door as a horizontal exit and if I need emergency generator. Thanks!

No to both because you have a four-story building. Per 1009.2.1 an elevator must be provided as part of an accessible means of egress in a building with four or more stories above the level of exit discharge - that would be a five-story building.

 

[ElArch]

You started a discussion about this same building and the same question in March. Your questions have been answered multiple times. Why start a new discussion of the same question now?

W

Post in thread 'Do the two stairs in the top and right need be accessible to exit level from the first floor directly?'

Jul 23, 2025

I hope I can reach you for the horizontal exit again.

In your image you are pointing to the door between Building A and Building B and ask, “Is this a horizontal exit?”

I guess you could make it a horizontal exit, but I can’t think of why you’d want to. You don’t need a horizontal exit between Building A and Building B, from Building B you can get to your second means of egress (Stair 1) within the 250’ exit access travel distance in Table 1017.2, you also confirm that in your title block.

Why is it that you guys think you need a horizontal exit?

[07/24 edit: see answer to...

• walker.t

• 

And this building does not fall under the IRC, so the Residential Code area is not the appropriate area for this discussion.

Looks like you created this new thread as the answer to my question in your first thread.


No to both because you have a four-story building. Per 1009.2.1 an elevator must be provided as part of an accessible means of egress in a building with four or more stories above the level of exit discharge - that would be a five-story building.

discussion

I finished 100% CD. Now a senior manager in this office said that is a horizontal exit and I disagree with it...

 

[Yankee Chronicler]

If the wall is a firewall, a door through the firewall can be used as a horizontal exit. The code never requires a horizontal exit where access to exit stairs is provided. The fact that it's a door through a firewall doesn't make it a horizontal exit if you meet the exit access travel distance without calling it a horizontal exit.

 

[ElArch]

If the wall is a firewall, a door through the firewall can be used as a horizontal exit. The code never requires a horizontal exit where access to exit stairs is provided. The fact that it's a door through a firewall doesn't make it a horizontal exit if you meet the exit access travel distance without calling it a horizontal exit.

That is what I learned from Walker. But he is so senior. I also respect his opinion. I want to confirm again. Now I am sure that is not a horizontal exit. Thanks all of you.

 

[walker.t]

But he is so senior. I also respect his opinion.

Regardless of their seniority, the person doing your quality control reviews can make a mistake, goes along with Item 1 (Humility) in this thread:

Thread 'Top 10 Qualities of a Professional'

Jan 18, 2025

Professionalism is a concept often discussed but not always clearly defined. In our field, which includes building inspectors, plans examiners, building officials, architects, and engineers, the expectations for professionalism are both explicit and implicit. Whether you’re reviewing a set of plans, conducting an inspection, or collaborating on a project, these qualities form the foundation of trust, respect, and competence. Let’s explore the Top 10 Qualities that define a true professional in the building code industry, especially for building officials who set the tone for their teams...

• jar546
• Replies: 6
• Forum: Building Code & Construction Related Articles

• 

 

[Joe.B]

“Anyone who has never made a mistake has never tried anything new.” -Albert Einstein

 

[Yankee Chronicler]

That is what I learned from Walker. But he is so senior. I also respect his opinion. I want to confirm again. Now I am sure that is not a horizontal exit. Thanks all of you.

Your exit diagram and your analysis confirms that it does not have to be a horizontal exit. Therefore, it's not a horizontal exit unless you choose to make it one. That means you will need standpipes on both sides of the horizontal exit on each floor. That's an added expense, plus additional maintenance for the life of the building. Why spend that if you don't need it?

Next, if you're going to make the doors through the firewall a horizontal exit, your exit diagram is incorrect for Building B. Remember, a horizontal exit is an exit. Once you pass through that door, you have exited from the building where you started. Your egress diagram shows travel from Building B through the firewall doors to a stair in Building A. That's incorrect. If the doors are a horizontal exit, egress travel from Building B ends at the door. Once people are in Building A, they are deemed to have exited from Building B. So the exit access diagram will end at the door, and the most remote point will shift to an apartment farther to the right and the maximum exit access travel distance will become significantly less than the 229'/231' you show.

 

[Yikes]

Hang on.
You have created an imaginary property line, and are placing a fire wall along that property line. IBC 503 says: "For purposes of determining area limitations, height limitations and type of construction, each portion of a building separated by one or more fire walls SHALL be considered to be a separate building."
Are you doing the ASW for any these reasons?

If "yes", now you have a separate building B with 85 occupants. IBC table 1006.3.4 says that building B needs more that one exit on all floors. 85 occupants per floor = minimum of 2 exits per floor.
As you mentioned, you currently have only one exit stair serving each floor of building B. Unless you can add another exit stair, the only other exit option for building B in your current plan is to make a horizontal exit through the ASW.

This has nothing to do with a generator, or using the elevator as an Accessible Means of Egress; Walker t is correct in post #3 and your QC person is incorrect (unless you have some kind of enclosed rooftop recreation space or something at a 5th level). You don't need a horizontal exit for purposes of avoiding a generator.

However, in my opinion, once you utilize the provisions of IBC 503, you need another exit on each floor of building B in addition to the Stair #3. For that reason, not the generator avoidance, your current pan needs the ASW to be a horizontal exit.

 

[Yankee Chronicler]

^^^ I confess that I missed the part about the firewall also being an imaginary property line.

I'm not sure that makes any difference.

 

[ElArch]

Hang on.
You have created an imaginary property line, and are placing a fire wall along that property line. IBC 503 says: "For purposes of determining area limitations, height limitations and type of construction, each portion of a building separated by one or more fire walls SHALL be considered to be a separate building."
Are you doing the ASW for any these reasons?

If "yes", now you have a separate building B with 85 occupants. IBC table 1006.3.4 says that building B needs more that one exit on all floors. 85 occupants per floor = minimum of 2 exits per floor.
As you mentioned, you currently have only one exit stair serving each floor of building B. Unless you can add another exit stair, the only other exit option for building B in your current plan is to make a horizontal exit through the ASW.

This has nothing to do with a generator, or using the elevator as an Accessible Means of Egress; Walker t is correct in post #3 and your QC person is incorrect (unless you have some kind of enclosed rooftop recreation space or something at a 5th level). You don't need a horizontal exit for purposes of avoiding a generator.

However, in my opinion, once you utilize the provisions of IBC 503, you need another exit on each floor of building B in addition to the Stair #3. For that reason, not the generator avoidance, your current pan needs the ASW to be a horizontal exit.

Yes, I separated it to two buildings because of the area limitation. But it says: "For the purposes of determining area limitations, height limitations and type of construction, each portion of a building separated by one or more fire walls complying with Section 706 shall be considered to be a separate building."
It didn't say for the purpose for egress exit. Therefore, the separated building didn't affect exits.

 

[Tim Mailloux]

are you sure you don't have a common path of travel issue with the most remote units in the south east corner of your plan?

 

[steveray]

“Anyone who has never made a mistake has never tried anything new.” -Albert Einstein

Thats bad when you are splitting atoms....

 

[Blazer]

Just because an occupant lives in Building B doesn't mean they cant use the means of egress provided in Building A. Separation of buildings using fire wall is for height and area purposes only and not to assess egress for each building independently. The door in the fire wall is considered exit access. If it swings in direction of travel from each side (dual egress) then either side can cross it to access an interior exit stairway. Your travel path (blue line) can be toward the west exit stair through the fire wall to show compliance with travel distance maximums. Tell your QC he can expect a bill from this panel of experts for teaching him the code .

 

[walker.t]

are you sure you don't have a common path of travel issue with the most remote units in the south east corner of your plan?

You mean here? There’s an exit stair at the end of the 44’ dead end corridor dimension, I’m scaling a little over 96’ from the farthest corner in the apartment at the bottom left.

 

[ElArch]

are you sure you don't have a common path of travel issue with the most remote units in the south east corner of your plan?

There is a stair at that side.

 

[Blazer]

Ensure you have a NFPA 13 system and not 13R, otherwise you are not permitted the 50ft dead-end maximum.

 

[Yikes]

ElArch, can you educate me further - - on this project, what is the physical difference on the building construction when you call that door in the ASW an "exit access" vs. a "horizontal exit"?
- You are already building a fire wall
- 1026.2 for a Horizontal Exit requires a 2 hour rated fire wall; if it's not a Horizontal Exit, 503 and Table 706.4 footnote (a) also requires a 2 hour rated fire wall anyway.

 

[Blazer]

1026.2 for a Horizontal Exit requires a 2 hour rated fire wall; if it's not a Horizontal Exit, 503 and Table 706.4 footnote (a) also requires a 2 hour rated fire wall anyway.

Please don't say Horizontal Exits require a fire wall. They only require a fire barrier at minimum but could be in a fire wall as well. If you utilize the fire wall in a building then its designers choice to consider it for required means of egress such as "Horizontal Exit". At the point one decides to use it for an "Exit" then along with it brings the refuge area requirements (3 sqft per person, etc.), number of exits and the standpipe on each side (905.4 #2).

 

[Yikes]

Please don't say Horizontal Exits require a fire wall. They only require a fire barrier at minimum but could be in a fire wall as well. If you utilize the fire wall in a building then its designers choice to consider it for required means of egress such as "Horizontal Exit". At the point one decides to use it for an "Exit" then along with it brings the refuge area requirements (3 sqft per person, etc.), number of exits and the standpipe on each side (905.4 #2).

You are correct, the exact wording of 1026.2 is fire wall or fire barrier.

So to summarize, on this project the main savings will be in the cost and placement of standpipes.

 

[Joe.B]

Well, the exact wording is:

1026.2 Separation.
The separation between buildings or refuge areas connected
by a horizontal exit shall be provided by a fire wall complying
with Section 706; or by a fire barrier complying with Section
707 or a horizontal assembly complying with Section 711, or
both. The minimum fire-resistance rating of the separation
shall be 2 hours. Opening protectives in horizontal exits shall
also comply with Section 716. Duct and air transfer openings
in a fire wall or fire barrier that serves as a horizontal exit
shall also comply with Section 717. The horizontal exit
separation shall extend vertically through all levels of the
building unless floor assemblies have a fire-resistance
rating of not less than 2 hours and do not have unprotected
openings.
Exception: [N/A to this conversation]
Horizontal exits constructed as fire barriers shall be continuous
from exterior wall to exterior wall so as to divide completely
the floor served by the horizontal exit.

In case anybody was wondering...

 

[Tim Mailloux]

You mean here? There’s an exit stair at the end of the 44’ dead end corridor dimension, I’m scaling a little over 96’ from the farthest corner in the apartment at the bottom left.

View attachment 16048

that's the spot I was concerned about. But it looks to be well under 125'