Occupancy classification

Also called: use group · occupancy group

The categorization of a building or space by how it is used: assembly, business, residential, institutional, and so on. Classification drives much of what follows in a code analysis, including allowable height and area, egress capacity, required fire separations, and sprinkler thresholds.

Enables: Egress (means of egress) Fire-resistance rating

Related: Building code

Architects

Why it matters

Misclassifying occupancy early is one of the most expensive code mistakes available, because so many downstream requirements key off it. It is also a genuinely interpretive judgment in mixed-use and unusual programs, which is why classification stays with the architect even when checking is automated.

Common question

Who decides a building’s occupancy classification?

The architect proposes it in the code analysis and the AHJ confirms it at plan check. Software can test the consequences of a classification, but the interpretive judgment belongs to the licensed professional.

Also in Fundamentals: Building code IBC (International Building Code) ICC (International Code Council) AHJ (Authority Having Jurisdiction) Jurisdiction Local amendments Egress (means of egress) Fire-resistance rating

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