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Rooftop Amenity / assembly space and Construction Type

So...

I now need to prove that what we'd had before works.

We'd had an enclosed amenity space at 672 sf. Since this was under 750sf, it could be classified as B. With Construction Type IIA works at 6 stories (IIB would not, at 4). We had two outdoor spaces on either side of this indoor space, at 420sf and 560sf respectively. So these could also be classified as B. None of these would require more than 1 exit (we had the two outdoor spaces exiting into the indoor space and then into the apartment corridor). And because they are small assembly spaces they do not contribute towards the 10% limit.

This should work, right? Any problems?
 
ETThompson1 said:
So...

I now need to prove that what we'd had before works.

We'd had an enclosed amenity space at 672 sf. Since this was under 750sf, it could be classified as B. With Construction Type IIA works at 6 stories (IIB would not, at 4). We had two outdoor spaces on either side of this indoor space, at 420sf and 560sf respectively. So these could also be classified as B. None of these would require more than 1 exit (we had the two outdoor spaces exiting into the indoor space and then into the apartment corridor). And because they are small assembly spaces they do not contribute towards the 10% limit.

This should work, right? Any problems?
Click to expand...
This is what I was requesting back in my earlier post (Post #5). This clarifies everything.

I would use Section 303.1.2, subparagraph 1, instead of subparagraph 2. With an occupant load factor of 15 sq/occ (assuming the outdoor areas have tables and chairs), the occupant load of each space is under 50 and can be classified as part of the occupancy to which it is accessory--in this case it would be the Group R-2. Since each space is no longer classified as a Group A-3, then there are no accessory occupancies; thus, there is no 10% limitation.
 
Right, but this is what we had *before* the client increased the size of the roof amenities. What we had before (described in my most recent post) works, but the increased size does not - unless, as you point out, we break it down into a series of smaller spaces.

I wanted to make sure that what we'd shown them before worked.

Thank you.
 
So, say even with the increased amenity spaces, we break it up into small spaces (either one at 960sf with others at 750, or all at 750). Isn't there some upper limit on how much we could do this? If it's not limited by the 10%, so could we have the whole top floor be a series of small amenity spaces under 750sf?
 
Actually, looking at the commentary I see that the small amenity spaces could be classified the same as the principal occupancy - ie, R-2. Also, they still need to be "accessory" to the principal use of the floor, which I guess is a matter of interpretation but at some point would limit the ability to have a floor of all small assembly spaces.
 
ETThompson1 said:
So, say even with the increased amenity spaces, we break it up into small spaces (either one at 960sf with others at 750, or all at 750). Isn't there some upper limit on how much we could do this? If it's not limited by the 10%, so could we have the whole top floor be a series of small amenity spaces under 750sf?
Click to expand...
There is no limit as long as the spaces are accessory to the Group R-2. In other words, they are provided for use by the residents and are not open to the public. If the one space is at 960 sq. ft., then it will need to be classified as a Group A-3 and is subject to the accessory occupancy 10% limitation. The other spaces would be classified as Group R-2.
 
ETThompson1 said:
Actually, looking at the commentary I see that the small amenity spaces could be classified the same as the principal occupancy - ie, R-2. Also, they still need to be "accessory" to the principal use of the floor, which I guess is a matter of interpretation but at some point would limit the ability to have a floor of all small assembly spaces.
Click to expand...
That is what I stated in Post #27. It is not a matter of interpretation, since the spaces are accessory to the Group R-2 if they are restricted to resident access.
 
I would assume that, if we had a series of smaller spaces, we'd need to watch exiting. The 750sf rooms can have one exit, but if they exit into one another, we'd need to evaluate the cumulative load. We'd also need to make sure we weren't going through more than one intervening space. Assuming we can meet all this, are there other exiting considerations we need to watch for?

And if these are truly classified as R-2, that would mean we do not need to separate them from the R-2 apartment hall as we would if it was a mixed occupancy?
 
ETThompson1 said:
I would assume that, if we had a series of smaller spaces, we'd need to watch exiting. The 750sf rooms can have one exit, but if they exit into one another, we'd need to evaluate the cumulative load. We'd also need to make sure we weren't going through more than one intervening space. Assuming we can meet all this, are there other exiting considerations we need to watch for?

And if these are truly classified as R-2, that would mean we do not need to separate them from the R-2 apartment hall as we would if it was a mixed occupancy?
Click to expand...
The code does not limit the number of intervening rooms, but you do have to consider cumulative loading. When the occupant load exceeds 49, then a space will be required to have two exit access doorways.

The enclosed R-2 assembly spaces will need to be separated from the hallway (i.e., corridor) with at least 30-minute fire partitions per Table 1020.1.
 
ETThompson1 said:
I would assume that, if we had a series of smaller spaces, we'd need to watch exiting. The 750sf rooms can have one exit, but if they exit into one another, we'd need to evaluate the cumulative load. We'd also need to make sure we weren't going through more than one intervening space. Assuming we can meet all this, are there other exiting considerations we need to watch for?

And if these are truly classified as R-2, that would mean we do not need to separate them from the R-2 apartment hall as we would if it was a mixed occupancy?
Click to expand...


how exactly are these rooms going to used? A 749SF space only requires one exit as long as you are using the Assembly Table and Chairs load of 1 person per 15SF. If this room is a multi function type of space that can be re-configured and used multiple ways you should use an occupant load of 1 per 7SF as a worst case scenario. What if a group of tenants removes all the tables and chairs and uses the spaces with just chairs, or standing room? Then your occupant load would be higher than 49 people and two exits would be required.


refer to the code commentary of section 1004.1.2 Areas without fixed seating:
The numbers for floor area per occupant load factor in the table reflect common and traditional occupant density based on empirical data for the density of similar spaces. The number determined using the occupant load factors in Table 1004.1.2 generally establishes the minimum occupant load for which the egress facilities of the rooms, spaces and building must be designed. The design occupant load is also utilized for other code requirements, such as deter-mining the required plumbing fixture count (see commentary, Chapter 29) and other building requirements, including automatic sprinkler systems and alarm and detection systems (see Chapter 9). It is difficult to predict the many conditions by which a space within a building will be occupied over time. An assembly banquet room in a hotel, for example, could be arranged with rows of chairs to host a business seminar one day and with mixed tables and chairs to host a dinner reception the next day. In some instances, the room will be arranged with no tables and very few chairs to accommodate primarily standing occupants. In such a situation, the egress facilities must safely accommodate the maximum number of persons permitted to occupy the space. When determining the occupant load of this type of occupancy, the various arrangements (e.g., tables and chairs, chairs only, standing space) should be recognized. The worst-case scenario should be utilized to determine the requirements for the means of egress elements. This is consistent with the requirements for multiple use spaces addressed in Section 302.1.
 
Yes, thanks for pointing that out. We usually assume spaces like this are 15/sf and try for that, and usually that's accepted. We'll discuss with the owner. Not sure if they're going to program rooftop type parties with that many people.
 
Another thing I want to check: I read on another forum (ICC) that the corridors are also considered an "accessory use". Is that correct? And if so, does this count towards the 10% rule?? I'm OK right now (because, per above, all my accessory spaces are "small" currently, so therefore do not contribute to 10%, but need to know because going forward the owner wants to expand the roof decks and I need to know the limitations.).

https://www.iccsafe.org/forum/non-s...sidl-codes/corridor-occupancy-classification/
 
Accessory use? Probably. Accessory occupancy? No. The 10% limitation is for accessory "occupancies" and not spaces that support the main occupancy and cannot be classified separately by an identified occupancy group.
 
Probably not too, which is why we've been steering them away from the larger amenity space. But they feel it may be needed to attract tenants. It's an issue we're seeing a lot of, as these rooftop amenity spaces are very popular right now.
 
# * # * #

ET,

A lot of us have enjoyed and hopefully learned something
from your topic and ensuing discussion........If you have
profited by coming here, would you also consider becoming
a regular contributor, ...telling others about this invaluable
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[ i.e. - A Sawhorse ] ?

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Yes, I will! It's been very helpful to have a group of knowledgable people to discuss this with. Thanks! I probably will have a few more q's before this is all done...
 
I have had jurisdictions such as Los Angeles approved of subdividing an otherwise large A-3 roof deck into smaller, 750 SF spaces, so that they were an accessory or even a "B" lounge occupancy. The separation was done with planters, and only a single 4' wide opening in the planters was allowed for "exit through intervening spaces".

See also http://www.ladbs.org/docs/default-s...ns/building-code/rooftop-garden.pdf?sfvrsn=11
 
RLGA said:
If you have the ability to break up the Group A-3 spaces into spaces that are 750 sq. ft., then you can classify them with the main Group R-2 occupancy. Or, you can have one assembly space that is 1,200 sq. ft. that is within the Accessory Occupancy limitation and classified as Group A-3, and the other assembly spaces are at 750 sq. ft. or less to be considered as Group R-2 spaces.
Click to expand...

Picking this thread back up as an example because I'm getting challenged on a similar issue on a different project.

I want to know if RLGA's option, quoted above, works fully for my current project. Here's my understanding, based on this thread, which I hope is right.

The "small Assembly space" provision, because it is in and part of the Occupancy Classification Chapter (3), allows me to classify these small assembly spaces as R-2, the main occupancy. This applies to height and stories as well - correct? These are analyzed as R-2 for height and stories. So R-2 works in my building because R-2 is allowed to be 5 stories up for type IIA construction. (In my case, the rooftop amenity is on the 5th story above the 2-story podium in my 7 story building). (Height works either way, since I'm allowed 85' for either, even though it's measured from the grade plane as required, not from the podium).

*However, the second option RLGA mentions, the 1,200 sf amenity space I'm less sure about. This is, as I understand it, governed by section 508.2. 508.2.1 tells me (I think) that I still have to still individually classify it as A-3, even though if it's under 10% of the area and therefore qualifies as an accessory occupancy. But then 508.2.1 also tells me that "The requirements of this code shall apply to each portion of the building based on the occupancy classification of that space." which I would read as the A-3 occupancy has to work as A-3.

But the very next section tells me "The allowable height and number of stories of the building containing accessory occupancies shall be in accordance with Section 504 for the main occupancy of the building." This makes it sound like for stories and height, this accessory space would be considered R-2. All this is somewhat confusing. Which is correct?

If the 1,200sf amenity space is classified as R-2, my building works for the same reason as the small assembly space. If I have to classify it, for purposes of height and stories, as A-3, it doesn't work, because A-3 is only allowed to be 4 stories up in IIA construction, and I'm on the 5th level above the podium.

So my questions are:
1. First of all, hopefully I'm right about the small assembly space occupancy.
2. For the "Accessory" provision in 508.2, do I consider the 1,200 sf amenity space as R-2 or A-3 for purposes of height and stories?

I tried to tell a colleague all this and they didn't believe me (we didn't have the code handy), so wanted to check.

Thanks!
 
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