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Requirements for walls supporting fire barriers/partitions

R

Redmund

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Dec 27, 2022
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California
If fire barriers or fire partitions occur on an upper level of a Type V-A building, the construction supporting these fire barriers/partitions is required to also be rated to the same hourly rating as the fire barriers/partitions that are being supported (IBC 707.5.1 & 708.4.1).

However, the code doesn’t specifically say that the walls that are a part of the supporting construction shall be installed as fire barriers or fire partitions, but is that the generally accepted practice? It will make a difference as to how any openings in the lower level rated supporting walls will need to be treated. That is, openings in a wall required to be rated just by IBC Table 601 only are not required to be protected, but what about the openings in walls that are supporting an upper level fire barrier or fire partition?
 
707.5.1 Supporting construction. The supporting construction for a fire barrier shall be protected to afford the required fire-resistance rating of the fire barrier supported. Hollow vertical spaces within a fire barrier shall be fireblocked in accordance with Section 718.2 at every floor level.

708.4.1 Supporting construction. The supporting construction for a fire partition shall have a fire-resistance rating that is equal to or greater than the required fireresistance rating of the supported fire partition.

The code states “supporting construction” and that might not be walls. Whatever is allowed with the supported barrier or partition is allowed with the supporting construction….. perhaps no greater protection is required, no less protection is allowed. It's "perhaps" because other parameters might bring in other codes and your question deals with openings.

However, I was certified as a plan checker twenty-five years ago. A lot has changed since then. I haven’t been tasked with plan checking for near fifteen years. I notice that when plan check questions come up here at this forum, which is most of it, there are answers that might conflict with each other. So wait for the real plan checkers to weigh in and find an answer that you like.
 
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steveray said:
They don't get built as FB or FP...Just 1hr construction....The openings don't need to be protected, the structure does...
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^^^ This. The fact that they may be walls doesn't mean they have to be walls. The supporting construction could as easily be 1-hour or 2-hour rated portal frames. (Unless they are required to be fire partitions or fire barriers to address something that occurs on the level on which they are located.)
 
Yankee Chronicler said:
^^^ This. The fact that they may be walls doesn't mean they have to be walls. The supporting construction could as easily be 1-hour or 2-hour rated portal frames. (Unless they are required to be fire partitions or fire barriers to address something that occurs on the level on which they are located.)
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Thanks to all who replied, this is very helpful. One follow-up question for a wall that is required to be fire rated, but its openings are not required to be protected, such as an interior bearing wall in Type II-A construction: Although door and window openings are not required to be fire protected, should penetrations of the wall such as electrical conduits still be fire-stopped? The reason for the question is that the frames of doors and windows, even if non-rated, should still provide some barrier to fire from quickly entering into the wall cavity space, however unless the penetrations in the gyp. bd. are fire-stopped, fire could potentially enter into the rated wall's cavity space very quickly.
 
Redmund said:
Thanks to all who replied, this is very helpful. One follow-up question for a wall that is required to be fire rated, but its openings are not required to be protected, such as an interior bearing wall in Type II-A construction: Although door and window openings are not required to be fire protected, should penetrations of the wall such as electrical conduits still be fire-stopped? The reason for the question is that the frames of doors and windows, even if non-rated, should still provide some barrier to fire from quickly entering into the wall cavity space, however unless the penetrations in the gyp. bd. are fire-stopped, fire could potentially enter into the rated wall's cavity space very quickly.
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And here is where it gets complicated....I say the bearing wall framing (R.O.) Should be wrapped and others say there is enough wood there that it does not matter...You choose....
 
steveray said:
And here is where it gets complicated....I say the bearing wall framing (R.O.) Should be wrapped and others say there is enough wood there that it does not matter...You choose....
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Actually, it is a metal stud framed wall, so the wall framing can't compartmentalize any fire that might got into the wall cavity as a wood framed wall might be able to do to some degree. However, IBC 714.4 talks about when through and membrane penetrations of fire rated walls are needed, and it calls out the wall types by name. It doesn't include a wall that is fire rated only due to Table 601 for Type of Construction. 1699313677257.png
 
Redmund said:
Actually, it is a metal stud framed wall, so the wall framing can't compartmentalize any fire that might got into the wall cavity as a wood framed wall might be able to do to some degree. However, IBC 714.4 talks about when through and membrane penetrations of fire rated walls are needed, and it calls out the wall types by name. It doesn't include a wall that is fire rated only due to Table 601 for Type of Construction. View attachment 11921
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A cased opening is an opening, not a penetration. If a wall on a lower story is rated solely because it supports a fire barrier or a fire partition on a higher story, than the wall needs to be rated, but openings in the wall do not need to be protected with rated opening protectives because there is no requirement to prevent or slow the propagation of a fire from one side of the wall to the other. We only care about the wall itself standing up for [ X ] hours.
 
Yankee Chronicler said:
... there is no requirement to prevent or slow the propagation of a fire from one side of the wall to the other. We only care about the wall itself standing up for [ X ] hours.
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I'm old enough to remember when I could successfully explain this concept by referring to the old "Right Guard" commercial from when I was a kid - - the walls stay standing, but you're not protected from your neighbor:
 
Redmund said:
Actually, it is a metal stud framed wall, so the wall framing can't compartmentalize any fire that might got into the wall cavity as a wood framed wall might be able to do to some degree. However, IBC 714.4 talks about when through and membrane penetrations of fire rated walls are needed, and it calls out the wall types by name. It doesn't include a wall that is fire rated only due to Table 601 for Type of Construction. View attachment 11921
Click to expand...
If there is a "continuous" layer of drywall over all bearing framing, there is not a concern...Assuming everything is 1 hour...

And I know you said VA, but for anyone else watching, don't miss the gimmies for "B" construction types:

1699360710950.png
 
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