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Does a penthouse mezzanine count toward high-rise status?

S

Shams Gannon

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Sep 9, 2019
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Austin Texas
I'm working on a ground up 4 over 1 podium building in Austin Texas. The upper portion will be III-A with an R-2 occupancy. Fully sprinkled of course.

We're looking to add a mezzanine to the top floor, but would like to stay under the 'high-rise' designation. IBC states the criteria for determining if a building is a high-rise is anything past 75' measured to the highest occupied floor, not to the height of the building construction. Elsewhere in the code it states a Mezzanine is part of the story below.

What is y'alls interpretation of occupied floor? If my upper most story was at 66' and it's mezzanine was at 76' would that put us into a high-rise category?

Thanks!
 
Yes, I would include the mezzanine floor when determining the height for fire department access.

If your mezzanine is 76-ft above the lowest level of fire department vehicle access, why not raise the fire department access by 18" and be done. That would seem to be a very subtle and doable fix on most sites.
 
You cant always take height out of a building, but grades can be brought up via some fill, and possible a retaining wall.
 
Attached is the illustration from the 2015 IBC commentary, which shows the measurement to the mezzanine.
 

Attachments

  • Figure 403-1-1 High-Rise Buildings.png
    Figure 403-1-1 High-Rise Buildings.png
    32.4 KB · Views: 16
I believe the use of "floor" instead of "story" when determining a high-rise building was intentional. An occupied roof is also a floor; thus, such a situation could create a high-rise building without adding any actual height to the building.

A mezzanine is a floor, thus its elevation would be considered when determining if a building is a high-rise or not.
 
This post by Chris Reeves on the ICC website (August 26, 2019) in reference to the 2015 code indicates an occupied roof is not a floor and not included in the highrise measurement.

www.iccsafe.org

Talking in Code: High-rise building definition - ICC

A building is considered a high-rise when there is an “occupied floor” more than 75 feet above the lowest level of fire department vehicle access...
www.iccsafe.org www.iccsafe.org
 
SH225 said:
This post by Chris Reeves on the ICC website (August 26, 2019) indicates an occupied roof is not a floor and not included in the highrise measurement.

www.iccsafe.org

Talking in Code: High-rise building definition - ICC

A building is considered a high-rise when there is an “occupied floor” more than 75 feet above the lowest level of fire department vehicle access...
www.iccsafe.org www.iccsafe.org
Click to expand...
Interesting...I had a jurisdiction reject a rooftop deck unless we did consider it a high-rise because of the deck's elevation. I'll have to keep this article handy. Thanks!
 
classicT said:
If your mezzanine is 76-ft above the lowest level of fire department vehicle access, why not raise the fire department access by 18" and be done. That would seem to be a very subtle and doable fix on most sites.
Click to expand...
I agree, an 18" rise in department access would be the easier route! We're in early planning stages and those heights were theoretical to help illustrate my question.
 
RLGA said:
Interesting...I had a jurisdiction reject a rooftop deck unless we did consider it a high-rise because of the deck's elevation. I'll have to keep this article handy. Thanks!
Click to expand...
We are trying to fix that in 2024, as the intent is clearly the occupied level/floor, not story.....And a roof is a floor when it is occupied...
 
I listened to a lot of debate about this subject during the code hearings....until my head exploded. I don't recall the results but I hope it gets a little more finality.
 
steveray said:
We are trying to fix that in 2024, as the intent is clearly the occupied level/floor, not story.....And a roof is a floor when it is occupied...
Click to expand...
It makes sense to me with the exception as is. There's no burning roof over your head to fall and smother you if you're on the roof. Plus it's fully ventilated...
 
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