How is 10% of Area Used in Accessory Occupancy?

My question is about small assembly occupancies and the total area of accessory occupancies per floor, with the 2021 IBC being the governing code. A small assembly occupancy can be considered part of the overall building occupancy if it is less than 750 sq ft and is accessory to that other occupancy (Section 303.1.2(2)).

My confusion comes when applying 508.2.3, which says that aggregate accessory occupancies cannot exceed 10% of the floor area.

Is the small assembly occupancy still considered accessory, or is it part of the overall occupancy?

Two scenarios have come up recently with multiple architects having differing interpretations. Assume the main occupancy is R-2.

1) Multiple small assembly occupancies scattered throughout the floor, that when added together, make up more than 10% of the floor area.

Is the 10% in aggregate or is it per small assembly occupancy?

One line of thought is that 303.1.2(2) is applied to each small assembly occupancy, meaning that they're all considered R-2.

2) A small assembly occupancy that is less than 10% of the floor area, but other accessory occupancies (storage for example) push the total accessory area over 10%.

Does the small assembly occupancy not contribute to the 10% since it's considered part of the overall occupancy?

Or does the small assembly occupancy + the storage occupancy need to be under 10%?

​Thanks in advance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe