IBC-IRC-Building-Code: Occupancy Classification Basics - Groups and Use — Flashcards

Occupancy classification is the code category assigned to a building or space based on its primary use (how the space is occupied and by whom). In the IBC, occupancies are grouped (A, B, E, F, H, I, M, R, S, U). Occupancy drives key requirements: allowable area/height, fire protection (sprinklers/alarms), egress, fire-resistance ratings, and separation between different uses.

Worked example(s)
Example 1: A small retail shop selling eyewear = Group M (Mercantile). A back office area is still part of the same suite; minor accessory uses typically don’t change the overall occupancy.
Example 2: A building has a restaurant (A-2) on the ground floor and apartments (R-2) above. This is a mixed-occupancy condition; code requires either separated occupancies (rated separations) or nonseparated (meet the most restrictive requirements in many areas).