Unlimited A-3 occupancy

[Henchalwoog]

Per 2015 IBC sec 507.6 one may construct an unlimited A-3 occupancy with type II construction - I would assume there can be accessory occupancies included (10% max above and beyond the total A-3 area - since the calculations of A-3 occupants is net only is the 10% based only on those areas or can that include intervening spaces such as circulation spaces? This is a large athletic facility with multiple courts and the intervening spaces would increase the base area considerably.

 

[arwat23]

Are you asking about how 1004.1.2 factors into this? You mention "occupants" (occupant load?). Where does it state A-3 only includes "net" floor areas?

 

[RLGA]

Accessory occupancies are permitted per Section 507.1.1. The 10% limitation applies to the gross floor area of the story where the accessory occupancies are located. Additionally, the 10% limitation applies to the aggregate area of all accessory occupancies, not to each individual accessory occupancy. Thus, if a building has an area of 10,000 sq. ft., the maximum area permitted for all accessory occupancies combined is 1,000 sq. ft. Additionally, the area of each accessory is limited to the tabular area listed in Table 506.2.

 

[Henchalwoog]

Are you asking about how 1004.1.2 factors into this? You mention "occupants" (occupant load?). Where does it state A-3 only includes "net" floor areas?

Working backwards the only areas you have for calculating occupant load is from the table (seated at tables, standing, etc)...so in a structure where there are courts and spectator areas they can be counted by their area - restrooms, storage areas, etc are not calculated since it is not a gross area calculation - only net...so then you are left with a finite figure for the area...is this the area you use to allow a max 10% accessory occupancy? Hope that helps...

 

[arwat23]

Working backwards the only areas you have for calculating occupant load is from the table (seated at tables, standing, etc)...so in a structure where there are courts and spectator areas they can be counted by their area - restrooms, storage areas, etc are not calculated since it is not a gross area calculation - only net...so then you are left with a finite figure for the area...is this the area you use to allow a max 10% accessory occupancy? Hope that helps...

Net floor area isn't a factor for determining the 10% accessory space. In this situation, net floor area only applies when calculating the OL. When determining the area of the A-3 classified space, use gross floor area.

Storage rooms can have the function of "accessory storage areas" - 300 gross. Occupancy classification (chapter 3) and function of space (1004.1.2) aren't the same thing.

 

[mtlogcabin]

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 in Table 506.2 for each such accessory occupancy.

 

[walker.t]

where there are courts and spectator areas

Are you sure you’re A-3 and not A-4?

2021 IBC 303.5 Assembly Group A-4 (partial quote, emphasis added]
Group A-4 occupancy includes assembly uses intended for viewing of indoor sporting events and activities with spectator seating…

2021 IBC Commentary on 303.4 Assembly Group A-3 (partial quote)
Some of the uses listed as examples in Group A-3 are more appropriately classified as Group A-4 or A-5 where there is spectator seating provided. An indoor tennis court where no spectator seating is provided is a Group A-3 occupancy. Add spectator seating and it becomes a Group A-4 occupancy.

 

[bill1952]

Are you sure you’re A-3 and not A-4?

Hmmm...if there is no seating, but lots of spectators who just stand, is it A3 or A4? Funny how code can look different when presented differently.

At April hearings one of my proposals separated three mostly unrelated requirements into a numbered list. Several engineers injected. One said they'd never seen it before. The three sentences had been there for many editions, unchanged.

 

[Henchalwoog]

Are you sure you’re A-3 and not A-4?

Yes - no permanent seats - only spectator areas so by the word of the code it would be A-3 (although I am sure folding chairs would end up being there)

 

[walker.t]

Yes - no permanent seats - only spectator areas so by the word of the code it would be A-3 (although I am sure folding chairs would end up being there)

Thank you, just wondering. I assume that by “spectator seating” the code intends permanent fixed seating, not folding chairs, “spectator seating” is not a defined term. Depending on the size of the area for folding seats, I wonder if a plans reviewer would consider your “spectator area” to be “spectator seating” even if the seating is only temporary.

 

[steveray]

There always ends up being spectator seating....

 

[RLGA]

There always ends up being spectator seating....

Agreed. If the floor area includes more space than is needed for playing the sport, which includes the court itself plus the immediate surrounding area (i.e., run-off space or free zone), that extra area becomes a spectator seating area, whether fixed or not. I always include those areas when determining occupant load using the concentrated assembly occupant load factor, unless bleachers are provided; in that case, I use the fixed seating factor, as per Section 1004.6.

 

[Henchalwoog]

Thank you, just wondering. I assume that by “spectator seating” the code intends permanent fixed seating, not folding chairs, “spectator seating” is not a defined term. Depending on the size of the area for folding seats, I wonder if a plans reviewer would consider your “spectator area” to be “spectator seating” even if the seating is only temporary.

Yes - I am taking the areas at 7 sq ft per person since I KNOW there will be chairs there

 

[Henchalwoog]

Agreed. If the floor area includes more space than is needed for playing the sport, which includes the court itself plus the immediate surrounding area (i.e., run-off space or free zone), that extra area becomes a spectator seating area, whether fixed or not. I always include those areas when determining occupant load using the concentrated assembly occupant load factor, unless bleachers are provided; in that case, I use the fixed seating factor, as per Section 1004.6.

Correct - so it sounds like the consensus is that while the spectator areas are calculated on a net area basis for occupant load the accessory areas are calculated on the gross area of the building...the issue I have is while the assembly areas are defined there are other areas (B occupancy for instance that wish to be classified as "accessory") that are also a part of the entire building...so do I take the assembly areas AND the associated circulation areas to calculate how much area the accessory B occupancy can occupy or just the assembly areas?

 

[RLGA]

...so do I take the assembly areas AND the associated circulation areas to calculate how much area the accessory B occupancy can occupy or just the assembly areas?

You use the entire story with all occupancy groups.

For example, if a story has 10,000 sq. ft. and the Group A-3 occupancy covers 9,000 sq. ft., the Group B occupancy is limited to 1,000 sq. ft. (i.e., 10% of 10,000 sq. ft.). The Group A-3 occupancy cannot be less than 9,000 sq. ft. in the 10,000 sq. ft. building because that would mean the difference in area occupied by accessory occupancies would be greater than 10% of the story's area.

 

[Henchalwoog]

Agreed...but if one plays the devil's advocate...what about toilet facilities and storage areas? Do they belong in with the A (main occupancy) or the B (accessory occupancy) if they are shared?

 

[walker.t]

the consensus is that while the spectator areas are calculated on a net area basis for occupant load

My comment was to confirm that you are A-3 and therefore qualify for unlimited area per 507.6.

that extra area becomes a spectator seating area, whether fixed or not

I’m not sure if he’s saying for purposes of only occupant load calculation or also occupancy classification.

do I take the assembly areas AND the associated circulation areas

The associated circulation areas are part of the assembly areas, but as noted in #3, #6, and #15 you use the area of the entire story to calculate the allowable area of an accessory occupancy.

 

[mtlogcabin]

What is the sq footage of the entire building?

 

[RLGA]

Agreed...but if one plays the devil's advocate...what about toilet facilities and storage areas? Do they belong in with the A (main occupancy) or the B (accessory occupancy) if they are shared?

If the Group A-3 occupancy (although I believe it’s a Group A-4 occupancy, since you admit there are spectator seating areas) is the primary occupancy, I would include the restrooms as part of the Group A occupancy. If the storage is not accessory to either the Group A or Group B occupancies, then it is a Group S occupancy and subject to the 10% limitation. However, according to IBC Section 311.1.1, storage areas that are accessory to another occupancy group are considered part of that other occupancy group. Therefore, if a storage room is used to store sporting equipment for the courts and is accessed from the Group A occupancy, it is considered part of the Group A occupancy. If it is a storage closet for office supplies within the Group B occupancy area, then it is part of the Group B occupancy group.

 

[Henchalwoog]

What is the sq footage of the entire building?

65,000 sq ft

 

[walker.t]

65,000 sq ft

If you’re Type IIA maybe you can get an extra 3000 s.f. over the Table 506.2 S1 value for either A-3 or A-4 with a frontage increase.

If you quality for an unlimited area A-3 building per 507.6 (building is sprinklered and surrounded by yard or public way at least 60’ wide) then you quality for and unlimited area A-4 building per 507.4 (one story maximum, any construction type other than Type V, must be sprinklered and be surrounded by 60’ open space.)