2021 IBC 1023.5?

[steveray]

Wonder who else has seen this and has as much discomfort as I do or clarification on what exactly they are trying to do?



I have not read through and seen any other changes or requirements that may go along with this. What I see here is the ability of the floor system diaphragm(s) in a 5A 4 story 13R building (1Hr floor/ 1 Hr enclosure) to enter and become the landing for the stairs (cantilever). No fireblocking enforceable at the plane of the enclosure. And that open web truss or I-joist floor system maybe gets fireblocking or draft stopping every 1000sqft or so, and then we have all of those penetrations of the diaphragm (bearing walls, wiring and boxes, plumbing, etc.) with unfettered access to the exit enclosure? And No suppression in the floor per 13R.....It may not be a huge deal in a perfect world if everything gets fire rated properly, but it still makes me very uneasy....

Am I nuts or is that? Is the intent only single member penetrations, not a rated diaphragm? Just trying to wrap my brain around what seems to be a really bad idea....

Thanks!

 

[RLGA]

I think it means just as it states, "Structural elements," per the examples given. A structural diaphragm itself is not a structural element but rather a structural system consisting of several structural elements. JMHO.

 

[Tim Mailloux]

if thoese penetrating structural lements are in any way supporting the rated stair construction the structural elements would also need to be rated.

 

[steveray]

if thoese penetrating structural lements are in any way supporting the rated stair construction the structural elements would also need to be rated.

Correct...and they would be in VA construction...But it would be "membrane" protection, not individual encasement...

I think it means just as it states, "Structural elements," per the examples given. A structural diaphragm itself is not a structural element but rather a structural system consisting of several structural elements. JMHO.

Thanks Ron, I have a greater comfort with that, my concern there Is that I haven't seen a rated wood penetration of a 1hr gyp assembly....The plans I have are.....lacking in the details in this area...So I will attempt to figure out exactly what they are trying to accomplish. I just see wood joists on both sides of the FB and there is no good section or detail...

 

[Tim Mailloux]

Correct...and they would be in VA construction...But it would be "membrane" protection, not individual encasement...


Thanks Ron, I have a greater comfort with that, my concern there Is that I haven't seen a rated wood penetration of a 1hr gyp assembly....

I would disagree. Stair enclosure are fire barriers and are required to be supported by structural elements with an equivalent or greater fire rating. Any beams the penetrate the shaft and structurally support the shaft or stair would need to be fired rated and any columns supporting those structural members would also need to be fire rated.

 

[Sifu]

From the code change proposal.

E98-18
IBC: 1023.5, (IFC[BE] 1023.5)
Proponent: Lee Kranz, City of Bellevue, WA, representing City of Bellevue, WA
(lkranz@bellevuewa.gov)

2018 International Building Code
Revise as f ollows:
1023.5 Penetrations. Penetrations into or through interior exit stairways and ramps are prohibited
except for the following:

1. Equipment and ductwork necessary for independent ventilation or pressurization.
2. Fire protection systems.
3. Security systems.
4. Two-way communication systems.
5. Electrical raceway for fire department communication systems.
6. Electrical raceway serving the interi exit stairway and ramp and terminating at a steel box not
exceeding 16 square inches (0.010 .
7. Structural elements supporting the interior exit stairway or ramp or enclosure, such as
beams or joists.
Such penetrations shall be protected in accordance with Section 714. There shall not be
penetrations or communication openings, whether protected or not, between adjacent interior exit
stairways and ramps.
Exception: Membrane penetrations shall be permitted on the outside of the interior exit stairway
and ramp. Such penetrations shall be protected in accordance with Section 714.4.2.
Reason:
It is common for structural elements such as beams and joists to penetrate interior
exit stair and ramp shaft enclosures as part of the floor framing. This is commonly know as
platform framing. Section 713.1 specifically excludes interior exit stairways from the shaft
requirements and there isn’t any direction provided in 1023 for structural elements penetrating
into a stair shaft. Lacking code guidance in 1023 most building officials are using Section 713.8
provisions for structural elements. The proposed language to be inserted in Section 1023.5 is
needed for interior exit stairways and ramps and is verbatim to that found in Section 713.8 for
shaft enclosures.
Cost Impact
The code change proposal will not increase or decrease the cost of construction . This code change
is for clarification only and will not impact the cost of construction. Internal ID: 100
E162

 

[steveray]

Tim, what do you disagree with? Everything structural in VA gets a one hour rating and it is a one hour exit enclosure up to 4 stories....?

 

[steveray]

Sifu,
I can find this, but I was looking for actual voting numbers to see how many people decided this for the rest of us.....


Do you know if the publish the vote tally anywhere?

Nevermind....scrolled all the way down...



Doesn't look like it went to OGCV?....That explains why I didn't vote against it....Nice to know that about 300 people (or less) control the code....