Question - 16 from Practice exam - Code question
Hey this will be a little long but I will really appreciate if someone takes the time to explain to me how that works.
Here is the question and the explanation
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Refer to the exhibit.
A developer hires an architect to design a sprinklered apartment building with occupancy R-2 for a vacant parcel of land in a high-density neighborhood. The developer wants the apartment building to have the maximum number of floors allowed by zoning. The land has the following zoning requirements:
- The maximum FAR is 3.5
- Building height limit is 85'
Which construction types should the architect consider using? Check the three that apply.
| A. | Type I-A |
| B. | Type II-A |
| C. | Type III-A |
| D. | Type V-A |
| E. | Type I-A podium with Type III-A above |
| F. | Type I-A podium with Type V-A above |
CORRECT RESPONSES
Type I-A
The maximum number of stories the client can build is six; Type I-A has unlimited stories.
Type I-A podium with Type III-A above
One story of Type I-A podium plus five stories of Type III-A meets the six-story requirement.
Type I-A podium with Type V-A above
Two stories of Type I-A podium plus four stories of Type V-A meets the six-story requirement.
CALCULATIONS
1. For the maximum gross square footage: 10,200 sf (site area) x 3.5 (FAR) = 35,700 sf
2. For the length of the building footprint: 60' (length of the site) - 10' (front setback) - 10' (rear setback) = 40'
3. For the width of the building footprint: 170' (width of the site) - 15' (side setback) - 15' (side setback) = 140'
4. For the maximum building footprint = 40' x 140' = 5,600 sf
5. For the number of floors: 35,700 sf / 5,600 sf = 6.375 floors, rounded to 6 floors
Here is my concern
IBC 510.4 Provision 6
What am I missing?
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Here’s a thread on this very question:
https://are5community.ncarb.org/hc/en-us/community/posts/13269251688215-PA-practice-questionThe above link also references *another* thread on the same question!
Basically: the question isn’t written in the most clear way and has already been flagged for review.
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Ah, I see. I think there's two things going on with respect to the portion of the code you reference:
One is that it's making a comment on the allowable *height* not the allowable number of stories, which don't end up imposing new limitations in this particular question -- we can still fit six (or seven) stories per our FAR and setback constraints.
The other is that the IBC allows us to consider the part of the building that forms the podium as one distinct building and the part of the building that sits on top of the podium as a completely separate building... so long as certain provisions are met, one of which is the one you cited related to building height. It's not really communicated very clearly, but I read that last provision to mean that the part of the building constructed on the podium can be as tall as a regular, non-podium building (governed by table 504.3) but the non-podium building measurement begins at grade, and our building measurement begins at the podium.
I find this particular code section really confusing and if I were approaching it with no professional experience I'm not sure how I'd interpret it. (And I may still be reading it wrong!) But I do know from experience that the whole business case for podium construction is that it allows us to build taller buildings than we would otherwise be permitted to build. If we were bound by the same height restrictions, we'd have no reason to select podium, we'd already be in compliance, and the whole section would be moot.
For what it's worth, I am not an expert in this part of the code, but the parts of the code that I do know a lot about can be surprisingly confusing, incomplete, inconsistent, and sometimes even fully wrong. For example the IBC made no mention of unvented roofs until something like 2015! (We've been doing them for a lot longer than that). Anyway, the code is written by volunteers and our industry doesn't always do a good job of communicating our intent clearly.
Hope this gets at what you were asking a bit better.
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Hi Dzhulia -
IBC 510.2 allows for portions of the building to be considered separate buildings only in terms of maximum allowable area, continuity of fire walls, and number of stores (i.e. not total building height, which is measured from the grade plane) when certain conditions are met. For this question, this means that you can build a type I-A podium (which has an unlimited number of stories) plus either a type III-A or V-A portion above, which will be limited to 4 or 5 stories, respectively. So, for each of these choices, you can build a 7-story project that fits all of the allowable floor area - 3 stories of I-A with 4 stories of V-A above, for example.
Note that it doesn't matter how you distribute the floor area for this question - it can be 6 full lot coverage floors plus a smaller floor above, or you can divide the total allowable floor area amongst 7 equal floors of 5,100sf each - however that's irrelevant for this question.
IBC 510.2, provision 6 is important but I'd say doesn't apply to this ARE question because the question doesn't provide the table that you need (504.3) to analyze if you comply with that provision. If you find yourself thinking about exceptions to the building code or other tables you'd need to answer a question on the ARE, I'd say you're getting off track - NCARB has stated that they'll provide you with the code tables/references that you need to answer each question, you're not expected to memorize any of this information.
That said - this provision says that for podium construction, the total height of the project is limited to the lower of the allowable heights for the construction types used. I-A is unlimited and V-A and III-A residential have maximum heights of 70 and 85' respectively according to table 504.3 - therefore the total height will be limited to 70 or 85'. You can certainly fit 7 floors within these maximum allowable heights for a residential building.
Just a test taking tip on this particular question - I-A is pretty clearly correct because it allows an unlimited number of stories. Choices B, C, and D only allow either 4 or 5 stories, so you couldn't fit all of the allowable floor area within those numbers of floors (your math on this is all correct). So, even without understanding the podium choices, you can get this correct if you know I-A is correct, and can eliminate the other 3 incorrect choices.
Chris Hopstock RA
Black Spectacles
ARE Community -
No problem, glad I could help. That's a great way of summarizing it :)
Chris Hopstock RA
Black Spectacles
ARE Community
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