Huge industrial building with huge lunch/break room

[PatrickGSR94]

Well, first, the break room is an assembly Group A-2 per Section 303.3 ("Restaurants, cafeterias and similar dining facilities") . Both the Group B and Group A-2 can be considered accessory occupancies per Section 508.2 if the aggregate of both areas does not exceed 10% of the overall story floor area.

Was the "unlimited area" determination based on construction type (Type IA) or based on requirements per Section 507? If the former, then there should be no problem. If the latter, then you'll have to consider Section 507.3.1 for including a Group A-2 within an unlimited area building.

Just noticed in the 2012 Commentary that the requirements of 507.3.1 A-2 in an unlimited area building do not apply when the A-2 area is accessory to the main occupancy. 507.1 Exception: other occupancies shall be permitted in unlimited area buildings in accordance with 508.2. 508.2 Accessory Occupancies, less than 10% of the overall area of the story, and then 508.2.4, no separation is required.