Mixed Use Occupancies are each individually classified by its primary occupancy.

• A. Mercantile Occupancies
• B. Residential Occupancies
• C. Institutional Occupancies
• D. Mixed Use Occupancies

Answer: (D)

In mixed-use buildings, each portion of the structure is treated according to its own primary occupancy. This reflects the reality that different uses carry different fire hazards, occupancy loads, and life-safety needs. By classifying each part by its specific occupancy, the code can apply the appropriate fire resistance, means of egress, suppression, and detection requirements to the exact risk present in that area. For example, a section used for mercantile purposes may have different egress and fire protection demands than an adjoining residential section. This per-occupancy approach ensures protections are tailored to the actual use of each portion rather than imposing a one-size-fits-all rule on the entire building. The other options are examples of occupancy types themselves, not the method by which mixed-use structures are classified.