How do fire resistance requirements vary by occupancy type in building design?

• A. Different occupancies require different FRR for walls, floors, and shafts to reflect risk, travel distances, and egress needs.
• B. FRR requirements are identical for all occupancies to simplify design.
• C. FRR only applies to walls, not floors or shafts.
• D. FRR depends only on building height, not occupancy type.

Answer: (A)

Fire resistance ratings aren’t the same for every building because different uses create different fire risks, occupant hazards, and egress needs. When a building mixes or has specific occupancy types, codes require different minimum fire-resistance ratings for walls, floors, and vertical shafts to slow fire spread and give people time to escape. Spaces with higher occupancy, more complex egress paths, or greater potential for rapid fire growth typically need stronger ratings to maintain compartmentalization and protect stair enclosures and exits. So the correct idea is that FRR depends on occupancy type and applies to multiple elements (not just walls), reflecting the level of risk and the necessary time for safe evacuation. Height can influence design choices, but occupancy type is a primary driver of the required ratings, which is why this option is the best fit.