A protected stairway enclosure in a three-story building must be enclosed from its highest point to its lowest point by a minimum fire rating of how many hours?

• A. One
• B. Two
• C. Three
• D. Four

Answer: (A)

The protected stairway enclosure must act as a continuous fire barrier along the full height of the stairs to keep the egress path safe. For a three-story building, the code requires this enclosure to have a minimum fire-resistance rating that spans from the highest floor to the lowest, and that rating is one hour. In other words, the walls and doors around the stairwell must resist fire for at least 60 minutes, ensuring occupants can evacuate and responders can use the stairs during an incident. Longer ratings are only required for taller buildings or more demanding scenarios.