Can an accessory occupancy in a unlimited floor area building, be two story?

[Fast_Edd1e]

Michigan Building Code 2021
40,000sf type A-3 single story pre-fab structure IIB construction with Fire suppression

Doing a code review for a possible trampoline park. The main 40,000 sf portion of the building would be considered Unlimited area per section 507.6 for A-3 of IIB. Owner is wanting to add a 3,000 sf (2) story appendage to the footprint. First floor will be A-3, second floor will be A-2 party rooms.

So my problem is that the building does not fall into unlimited if there is a second story. So can I consider it an Accessory occupancy.

But my problem is understanding this part of section 508.2.3
"The allowable area of the building shall be based on the applicable provisions of section 506 for the main occupancy of the building. Aggregate accessory occupancies shall not occupy more than 10 percent of the floor area of the story in which they are located and shall not exceed the tabular values for nonsprinklered buildings.

So the accessory A-2 is on another story. Is it still considered accessory to the building A-3 if there is no other A-3 on that "story"

Or am I going to get back looped into the building area chart and not considered Unlimited because it has (2) stories.

 

[Yankee Chronicler]

3,000 s.f footprint, or 3,000 s.f. for both stories combined (1,500 + 1,500)?

It doesn't matter whether or not the new second story is classified as accessory to the first floor (I would argue that it should not be, FWIW, based on IBC 303.1.2).

If any part of a building is two stories in height, the building is two stories in height. Michigan building code (per UpCodes)

507.5 Two-Story Buildings​

The area of a Group B, F, M or S building not more than two stories above grade plane shall not be limited where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

No A occupancies allowed for two-story unlimited area buildings.

Then look at 507.6. One story only.

507.6 Group A-3 Buildings of Type II Construction​

The area of a Group A-3 building not more than one story above grade plane, used as a place of religious worship, community hall, dance hall, exhibition hall, gymnasium, lecture hall, indoor swimming pool or tennis court of Type II construction, shall not be limited provided that the following criteria are met:

1. The building shall not have a stage other than a platform.
2. The building shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
3. The building shall be surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

 

[Fast_Edd1e]

3,000 s.f footprint, or 3,000 s.f. for both stories combined (1,500 + 1,500)?

It doesn't matter whether or not the new second story is classified as accessory to the first floor (I would argue that it should not be, FWIW, based on IBC 303.1.2).

If any part of a building is two stories in height, the building is two stories in height. Michigan building code (per UpCodes)



No A occupancies allowed for two-story unlimited area buildings.

Then look at 507.6. One story only.

Thank you.
They are wanting 3000 sf for each story of this appendage.

That is what I am thinking when they are wanting to add this added part of the building. They keep wanting to call it a mezzanine, but then say "party ROOMs".

Im guessing if they want this second story, I have to go back to the Area chart. With the frontage increse calculation I can get an A-3 IIB sprinkled up to 33,250. They originally want at least 40,000.

So they either need to nix the second story, or reduce overall square footage. Because the only other option is create a rated separation, and they are not going to want that.

 

[Yankee Chronicler]

Supposedly, Abraham Lincoln once said that you can call a dog's tail a leg, but what you have is still a dog with four legs, not five. Calling a level in a building a "mezzanine" doesn't make it a mezzanine unless it satisfies the definition of "mezzanine" Designers (particularly the unlicensed "building designers") like to play this game all the time. I deal with it regularly.

Definition of "mezzanine" from the Michigan code:

[BG] MEZZANINE. An intermediate level or levels between the floor and ceiling of any story and in accordance with Section 505.

I would need to see both the floor plans and a building section to properly evaluate the "mezzanineness" of this proposed new upper level. The basic criterion is that if it doesn't occur within a larger space on the ground story -- it's not a mezzanine.