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Vertical openings in stories adjacent to atrium

jonochshorn

Member
Joined
May 30, 2013
Messages
8
Location
Ithaca, NY
I have a sprinklered A-3 (library) occupancy with three stories, and the top two floors have vertical openings, so that all three stories are inter-connected. Section 712 of the 2015 IBC permits vertical openings in floor-ceiling assemblies only when they are "in accordance with one of the protection methods in Sections 712.1.1 through 712.1.16." Section 712.1.9 (Two-story openings) states that "a vertical opening that is not used as one of the applications listed in this section shall be permitted if the opening … does not connect more than two stories…" But the situation I am describing involves three inter-connected stories. And none of the other protection methods listed in Sections 712.1.1 through 712.1.16 applies.

However, does it matter if these three stories are adjacent to, and open to, an atrium, per 2015 IBC Section 404.6, exception 3? In other words, can these three stories be considered to be somehow part of the atrium (and therefore allowed to be inter-connected, like the atrium itself), rather than being considered as three stories adjacent to the atrium?
 
Good question

I think RGLA has a great answer for you, just give him a chance
 
The "atrium" can include as much as you want.....Can you afford to design n the smoke control to accommodate?

404.5 Smoke control. A smoke control system shall be
installed in accordance with Section 909.
 
Yes, smoke control can be accounted for in the design, but my question is really about whether "stories" can be a part of the atrium at all, and therefore not subject to section 712 vertical opening requirements that would otherwise prevent these three stories from being inter-connected. The definition of an atrium is an OPENING connecting two or more stories, where the definition of "stories" does not include balconies or mezzanines. So how can a "story" be in an atrium if the atrium is not itself a story, but rather an opening connecting stories? The smoke control requirement doesn't, by itself, place those adjacent stories in the atrium; it just requires that they be included in the smoke calculation for the atrium. But, as far as I can tell, they still retain their identity as separate stories that happen to be adjacent to and open to the atrium.
 
Think the typical hotel atrium with all of the balconies.....Or maybe envision an atrium with a tower in the middle....Everything "inside" the atrium rating is in the atrium and that volume gets taken into account with the smoke control...
 
"All the balconies" in a typical hotel atrium count as, yes, "balconies," and so are specifically excluded from being counted as "stories" in the Ch. 2 "Atrium" definition. In this same definition, the atrium is defined as an opening connecting stories. So why would you suggest that a "story" (and not just a balcony) can be considered to be "in" or "part of" an atrium? That is the essence of my question: where in the IBC is there any suggestion that a story (not just a balcony) can be part of an atrium? Put another way, if the opening connecting several stories creates the atrium, how can these stories—defining the atrium by bounding it—be simultaneously in an atrium? This has nothing to do with the smoke control issue, which applies to no more than three stories adjacent to the atrium (not in the atrium) that are allowed to be open to the atrium.

I would think that if there is a tower within an atrium and the tower consists of stories, then those stories help define the boundary of the atrium rather than being a part of the atrium.
 
I have a sprinklered A-3 (library) occupancy with three stories, and the top two floors have vertical openings, so that all three stories are inter-connected. Section 712 of the 2015 IBC permits vertical openings in floor-ceiling assemblies only when they are "in accordance with one of the protection methods in Sections 712.1.1 through 712.1.16." Section 712.1.9 (Two-story openings) states that "a vertical opening that is not used as one of the applications listed in this section shall be permitted if the opening … does not connect more than two stories…" But the situation I am describing involves three inter-connected stories. And none of the other protection methods listed in Sections 712.1.1 through 712.1.16 applies.

However, does it matter if these three stories are adjacent to, and open to, an atrium, per 2015 IBC Section 404.6, exception 3? In other words, can these three stories be considered to be somehow part of the atrium (and therefore allowed to be inter-connected, like the atrium itself), rather than being considered as three stories adjacent to the atrium?



Read through this and see if it helps


https://www.thebuildingcodeforum.co...-not-a-true-atrium-by-code.23260/#post-182830
 
Isn't the lowest floor part of a story?...Isn't it part of an atrium?....Show me where the code does not allow a room inside an atrium....As long as it meets all of the requirements such as low fire hazard, etc. it is allowed...
 
Maybe if you can post an elevation view of what you are describing might help us help you. Picture worth a thousand words;).
 
"Show me where the code does not allow a room inside an atrium..." Yes, the definition of an atrium seems consistent with the definition of a story. However, neither the Code nor the IBC Commentary suggest that this particular and unique type of story can have other stories in it that are somehow still part of the atrium. Because the atrium is defined as an opening connecting two or more stories, once you put another story in the atrium, the atrium, by definition, becomes smaller, since the new story now defines a smaller opening (and the atrium is the opening, not the story that is inserted). The 2015 IBC Commentary lists things that can go in an atrium (elevators and open stairways that are entirely within the atrium) but does not suggest that "stories" can be inserted into an atrium. The Commentary also says that "balconies associated with assembly occupancies and mezzanines are not considered individual stories that would contribute to the classification of a space as an atrium." So if you have a "room inside an atrium," then, by definition, the atrium—as an opening connecting several stories—must be outside that room. I've inserted an elevation of the three stories open to the atrium at issue here. These floors do not provide assemblies that are "continuous without vertical openings" as required by Section 711.2.2, nor do they meet the "two-story openings" exception in Section 712.1.9. So, once again, I ask whether this is consistent with the 2015 IBC.

fig12.jpg
 
Smoke control allows you to do wonderful things with open designs. However, independent egress at a separate location has to be offered to ensure a protected MOE is provided.

BTW if this is an existing building, why are you applying the 2015 IBC? I know that IEBC points you to the IBC if an atrium is involved in a change of occupancy.
 
If your floors are not required to be fire rated then you should not be in 711.2....
And atriums are allowed as a penetration per:
712.1.7 Atriums. In other than Group H occupancies, atriums
complying with Section 404 shall be permitted.

So the "other openings" can be part of the atrium or you can separate them with shaft construction...A floor plan would really be helpful...

And no wonder why a new library cost $40 million...
 
The floors should be fire-resistance rated since a sprinklered A-3 (library) occupancy on the 4th floor (yes, the three floors of the library are above a first-floor shop) needs to be Type III-A, II-A, or Type I. That the floors and columns have no fire-resistance rating is another story entirely (short answer: there was a prior NYS Code Variance).

So the floors are not fire-rated, but Section 711.3.2 still requires continuity except as permitted by Section 712. But Steveray is right: I should not have referenced Section 711.2 for the continuity requirement.

Reading the 2015 IBC Code Commentary, I'm getting mixed signals. On the one hand, the Commentary seems to suggest that spaces adjacent to the atrium can be considered part of the atrium, even if they do not meet other requirements in Section 712, as long as they meet the atrium provisions (basically for smoke control). But on the other hand, the smoke control rationale for atriums seems to be violated by suggesting that these three open stories—with permeable floor-ceiling assemblies that do not meet the other provisions of Section 712—are part of the atrium. Here's the relevant Commentary passage: "Exception 3 recognizes the desire to have at least some floors open to the atrium, and permits a maximum of three. ... The exception also states that the smoke control design must account for these spaces. This particular reference to the smoke control design does not require that the 6-foot-high (1829 mm) layer required by Section 909.8.1 be maintained in these spaces. Instead it is saying that if a smoke control system is required by Section 404.5, such spaces must be accounted for in terms of the hazard they pose to the atrium and to smoke migrating to other adjacent spaces or other stories open to the atrium. Essentially these spaces have simply increased the possible design fires that may send smoke into the atrium, thus threatening to send smoke throughout the building and other adjoining spaces."

In other words, the Commentary seems to envision adjacent spaces outside the atrium boundary that can be considered part of the atrium from the standpoint of smoke control. Such spaces do not intrinsically threaten adjacent spaces since any smoke originating from those spaces is directed into the atrium's smoke control system, where it stays in the vertical opening of the atrium. But in the condition I'm concerned about, with the three stories actually within the boundary of the atrium, smoke originating in one of the lower library stack stories would not be directed into the atrium's vertical opening, but would rise directly through the open floor-ceiling assemblies into the other adjacent library spaces.

I believe that this particular scenario was not envisioned when the atrium Code rules (or the Commentary) were written.

BTW, anyone wanting to look at floor plans of this library can see them at https://aap.cornell.edu/about/campuses-facilities/ithaca/mui-ho-fine-arts-library/project-details
 
I think i would be really concerned with the fuel loads all those books are and do not see any sprinklers. Also not sure if they are trying to consider this as multi level mezzanine.
 
The building is fully sprinklered. And the stack levels are too big to be considered as mezzanines, so they are designed as "stories" connected by an atrium. But even so, I agree with your assessment: the entire design (for many other reasons as well) is worrisome.
 
Come on... that is not a photo. It is blatant CGI.

It is absolutely infeasible on so many levels that I am wondering if this is even a serious post.
 
Nice photo of the Salt Lake City Library: From what I can see, it is configured as a classic atrium, with three "open" stories and the rest enclosed. But my question was not about the idea of an atrium in a library per se, but about whether the three open stack levels adjacent to the atrium could themselves be constructed of open steel grating, seemingly violating the requirements for vertical openings in Section 712. In any case, the building is real, the perspective was an early schematic rendering, and the actual atrium, as built, is shown below.

557
 
Hum

Is it one story or open area with a feature in it??

Like play gym just big

Or multi level laser tag

Or whatever you want to call it
 
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