R-2 Rooftop Patio and Number of Stories

[peach]

It doesn't qualify as either a story or occupiable space by code definitions; doesn't resolve getting these people out of danger in case of an emergency (either on the roof or below).. they need to get into exit stairways and out of the building.

 

[brudgers]

What is amazing to me is that some of the people who would allow 500 occupants to assemble four stories above grade on the roof of a wood framed building would require a 200 square foot leasing office on the ground floor to be sprinklered with a full NFPA 13 system.

 

[mark handler]

imhothe occupancy a-3 can not be above the thrid level (story).

Regardless of the definition of a story

the options as i see it are to change the area sq footage of the deck

or to change the type of construction.

as posted before

You can control occupancies

 

[Mr. Inspector]

I had a problem like this a few years back. A huge deck was being built at a bar for over 500 people and the only egress was through the small building that is not sprinklered.

 

[Dawgbark]

For some reason this looks familiar to a question I have seen elsewhere, but it was asked as if in California I think.

The person was asked what was the occupant load of the building, no one answered.

So, if it is not too late what is the occupant load of the building excluding the rooftop load?

Then, what is the square footage of the rooftop?

 

[Coug Dad]

Attended an ICC class last week where roof top "assembly" was discussed. The roof does not have an occupancy, although the means of egress has to be sized to accomodate the use. Therefore, a roof top pool deck would be allowed provided proper egress is provided.

 

[texasbo]

Attended an ICC class last week where roof top "assembly" was discussed. The roof does not have an occupancy, although the means of egress has to be sized to accomodate the use. Therefore, a roof top pool deck would be allowed provided proper egress is provided.

Huh, woulda never guessed...

 

[Papio Bldg Dept]

Huh, woulda never guessed...

More semantics, but yes, who woulda guessed? Seems like a lot of guessing. The 2012 & 2015 editions of the IBC are supposed to clarify this issue. The instructor referred back to the definition of a story in order to determine occupancy. Since a rooftop does not meet the definition (which has been posted many times already in this thread), there is no occupancy. Same reasoning why you don't classify a flat roof as and S or U occupancy if used as such. Anyway, I digress. His point then was to address the use, and design the means of egress accordingly for widths, number of exits, exit access, travel distance, cpt, etc.

I believe that is a fair and reasonable opinion about how to handle a 4 Story, roof top being used as an assembly occupancy. In otherwords. No occupanc. Same holds true if you fenced in an 8,000sf open air volleyball court with wood and stucco walls 12 feet high on top of a roof or at ground level. With no area modifications, this would exceed the allowable areas if we assigned it an occupancy classification per table 503. Do we really need to sprinkle the space to get an area increase? Has common sense flown the coop? I can tell you this AHJ would not assign an occupancy classification, whether up on a roof or not. Do you MOE calcs/design per the use/function and move on, in my opinion.

 

[brudgers]

More semantics, but yes, who woulda guessed? Seems like a lot of guessing. The 2012 & 2015 editions of the IBC are supposed to clarify this issue. The instructor referred back to the definition of a story in order to determine occupancy. Since a rooftop does not meet the definition (which has been posted many times already in this thread), there is no occupancy. Same reasoning why you don't classify a flat roof as and S or U occupancy if used as such. Anyway, I digress. His point then was to address the use, and design the means of egress accordingly for widths, number of exits, exit access, travel distance, cpt, etc. I believe that is a fair and reasonable opinion about how to handle a 4 Story, roof top being used as an assembly occupancy. In otherwords. No occupanc. Same holds true if you fenced in an 8,000sf open air volleyball court with wood and stucco walls 12 feet high on top of a roof or at ground level. With no area modifications, this would exceed the allowable areas if we assigned it an occupancy classification per table 503. Do we really need to sprinkle the space to get an area increase? Has common sense flown the coop? I can tell you this AHJ would not assign an occupancy classification, whether up on a roof or not. Do you MOE calcs/design per the use/function and move on, in my opinion.

The instructor was FOS. [302.1] Structures or portions of structures shall be classified with respect to occupancy

Nothing about stories or even buildings.

See Occupancy A5 for a counter example which shows the intent of the code.

 

[Papio Bldg Dept]

The instructor was FOS. [302.1] Structures or portions of structures shall be classified with respect to occupancy

Nothing about stories or even buildings.

See Occupancy A5 for a counter example which shows the intent of the code.

Good points. FOS might be a bit excessive.

Following your logic, what occupancy classification to roofs that aren't used for assembly would you assign?

 

[mtlogcabin]

What is the use?

 

[brudgers]

Good points. FOS might be a bit excessive. Following your logic, what occupancy classification to roofs that aren't used for assembly would you assign?

When someone says something as utterly stupid as "Occupancy doesn't apply" and then rationalizes it based on an unrelated definition rather than an actual reading of Chapter 3 and 4, they are obviously an idiot. © When they assert such stupidity as an instructor while presenting themselves as an expert and in the role of instructor, then they are FOS.

If the roof isn't being used as an assembly occupancy - though that is perhaps the most common for roofs which are not part of a dwelling, the occupancy would be determined based upon the same criteria as any other portion of the structure - e.g. a recreation area on the roof of the jail would be I, storage racks S, etc.

 

[alora]

...Following your logic, what occupancy classification to roofs that aren't used for assembly would you assign?

Following the code, it would be (underline, mine):

302.1 General. Structures or portions of structures shall be classified with respect to occupancy in one or more of the groups listed below. A room or space that is intended to be occupied at different times for different purposes shall comply with all of the requirements that are applicable to each of the purposes for which the room or space will be occupied. Structures with multiple occupancies or uses shall comply with Section 508. Where a structure is proposed for a purpose that is not specifically provided for in this code, such structure shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard involved.

 

[texasbo]

The fact remains, whether it is classified as an occupancy or not, that it is not a story, by definition. Being "not a story", it is not a violation of Table 503 in terms of height or area.

 

[Papio Bldg Dept]

Don't forget 1607.11.2.2 Special-purpose roofs.

Roofs used for promenade purposes, roof gardens, assembly purposes or other special purposes, and marquees, shall be designed for a minimum live load, Lo, as specified in Table 1607.1. Such live loads are permitted to be reduced in accordance with Section 1607.9. Live loads of 100 psf (4.79 kN/m2) or more at areas of roofs classified as Group A occupancies shall not be reduced.

Having re-read the thread, in particular mt's post on special-purpose roofs, proved to be more helpful for me in understanding the intent of the code than anything I have read or heard in the last week on this subject. It tells me that the intent of the code is to assign an occupancy classification to all buildings and structures.

Telling me to read 303.1 A-5, as brudgers suggests, does not clarify anything in regards to the discussion (for me at least). It simply tell he you considers the roof to have an occupancy.

I am then left to assume my instructor is/was an idiot, whom, full of excrement, misinformed the entire class and his ICC Code Committee (MOE), and now I am unable to determine the allowable heights and areas for the A occupancy on the roof because I can not determine a construction type for open air, non-story, occupancies (hence my earlier comparison/reference to an 8,000 sf A occupancy at grade with 3' wood stucco walls around the perimeter which was not addressed). Is that an A occupancy, Type VB construction limited to 1 story and 6,00sf and thererfore non-compliant? I am literally unable to ascertain a clear answer, which I don't believe makes anyone an idiot, nor full of stuff (not trying to change brudgers opinion of instructor, merely stating I don't agree it is that simple, and that opinion does little to advance the discussion).

Am I to assume we are now just haggling over price?

 

[Papio Bldg Dept]

Following the code, it would be (underline, mine):

Thanks alora. Between you, brudgers and mt, I see an intent in the code that wants to assign an occupancy to the roof as it is part of the building/structure, and other sections are using that occupancy classification to prescribe design standards (I do have some questions about various conditions for MOE to the roof, but I am confident if I re-read the code sections on stairs and roof access I will be able to answer them). I am however, more of the inclination that, as texasbo believes, Table 503, for heights and areas does is not applicable for occupancies of non-stories outside the definitions of the allowable building area. Using logic (however unapplicable, unfounded or inept my use of it may be), tends to lead me towards texasbo's conclusion. When brudgers does not agree with my instructor, from whom I have taken several ICC training classes, my lebenswelt tends to get a little shaky, I start looking at other examples where holding a project to Table 503 limitations would not make sense.

 

[texasbo]

Am I to assume we are now just haggling over price?

Maybe, but maybe not. I would be willing to discuss some additional peripheral subjects.

It's been established that the roof is not a story, and therefore not subject to height in stories.

In terms of area, the code is pretty explicit in its definition, so if you want to stick something on the roof, area has already been taken care of.

But let's say the occupied roof exceeded allowable height in feet. Would that be a violation? I would consider discussing it.

I do like poo poo humor though, so let's continue this.

 

[mtlogcabin]

The use on the roof and the height limits based on construction type should determine if the use is permitted.

Example a 4 story V-B hotel should not be permitted to have a assembly use on it as the use is more than 3 floors in height. change the construction type and it will work.

Could the same hotel have a heliport on the roof, or a small dining area with less an OL of less than 50?

 

[texasbo]

The use on the roof and the height limits based on construction type should determine if the use is permitted.Example a 4 story V-B hotel should not be permitted to have a assembly use on it as the use is more than 3 floors in height. change the construction type and it will work.

Could the same hotel have a heliport on the roof, or a small dining area with less an OL of less than 50?

MT: note that the code uses the term stories, not floors. It doesn't allow assembly more than 3 stories in height, not more than 3 floors. In the case at hand, it is not more than 3 stories.

 

[Dawgbark]

No one knows what the occupant load of the building is, what the sq.ft. of the roof top is.

What If one person of the condo complex owns the top floor and the roof top which is possible the the occupant load is one.

 

[Builder Bob]

One big problem is that this is in the code ------ and does not work very well with the rest of the code ....i.e. how do you determine occupant load without knowing the type of use of the area???

1004.8 Outdoor areas. Yards, patios, courts and similar outdoor areas accessible to and usable by the building occupants shall be provided with means of egress as required by this chapter. The occupant load of such outdoor areas shall be assigned by the fire code official in accordance with the anticipated use.

Where outdoor areas are to be used by persons in addition to the occupants of the building, and the path of egress travel from the outdoor areas passes through the building, means of egress requirements for the building shall be based on the sum of the occupant loads of the building plus the outdoor areas.

Exceptions:

1. Outdoor areas used exclusively for service of the

building need only have one means of egress.

2. Both outdoor areas associated with Group R-3 and

individual dwelling units of Group R-2.

 

[brudgers]

Thanks alora. Between you, brudgers and mt, I see an intent in the code that wants to assign an occupancy to the roof as it is part of the building/structure, and other sections are using that occupancy classification to prescribe design standards (I do have some questions about various conditions for MOE to the roof, but I am confident if I re-read the code sections on stairs and roof access I will be able to answer them). I am however, more of the inclination that, as texasbo believes, Table 503, for heights and areas does is not applicable for occupancies of non-stories outside the definitions of the allowable building area. Using logic (however unapplicable, unfounded or inept my use of it may be), tends to lead me towards texasbo's conclusion. When brudgers does not agree with my instructor, from whom I have taken several ICC training classes, my lebenswelt tends to get a little shaky, I start looking at other examples where holding a project to Table 503 limitations would not make sense.

See section 506.4 Re: The original post

The building described has more than one story above grade plane, therefore total allowable area for the building is determined by multiplying the number of stories in Table 503 by the allowable area of each story in table 503 (as the general case). This would allow an R2 occupancy on the roof but the occupied area of the roof would be counted against the total allowable area of the building under section 506.4.

Example:

Type IIIA Occupancy R2 would have a total allowable area of 24k sf x 4 stories = 96k sf.

If the rooftop area was 16k sf, then the maximum aggregate area of the four stories would be 80k sf with no story being more than 24k sf.

However, the proposed rooftop use is an assembly occupancy and would require a construction type which allows a four story assembly occupancy and would count against the total allowable area of the building under 506.4.

 

[brudgers]

No one knows what the occupant load of the building is, what the sq.ft. of the roof top is. What If one person of the condo complex owns the top floor and the roof top which is possible the the occupant load is one.

Residential Occupancies have an occupant load of 1/200 sf. See Table 1004.1.1

 

[brudgers]

Maybe, but maybe not. I would be willing to discuss some additional peripheral subjects. It's been established that the roof is not a story, and therefore not subject to height in stories. In terms of area, the code is pretty explicit in its definition, so if you want to stick something on the roof, area has already been taken care of. But let's say the occupied roof exceeded allowable height in feet. Would that be a violation? I would consider discussing it. I do like poo poo humor though, so let's continue this.

Yeah, just because you don't comprehend something, it doesn't exist.