Which factor is commonly used to determine a protected stairwell's fire rating?

• A. Building age
• B. Occupancy
• C. Stair height
• D. Exterior color

Answer: (B)

Occupancy type drives the required fire resistance of protected stairwells. The reason is that different uses create different fire hazards and occupant risks, so codes set minimum fire-resistance ratings for exit enclosures to ensure people can evacuate safely and the stairs stay intact long enough for emergency actions. A high-risk, high-occupancy space (with more people and higher fire loads) typically requires a more substantial rating than a simpler occupancy. Building age can influence retrofit considerations but doesn’t determine the rating itself; stair height affects design details, not the fire-resistance requirement; exterior color has no bearing on fire protection.