Comprehensive and Detailed Step-by-Step Explanation:
Fire Resistance and Stair Separation:
According to NFPA 101 (Life Safety Code), Section 7.2.2.5, where a fire-rated separation extends 10 feet from a stair enclosure, the separation fire resistance does not need to exceed 1 hour if the openings have a ½-hour fire protection rating.
Why ½ Hour is Acceptable:
Openings with a ½-hour fire protection rating are sufficient to limit fire spread in lower-risk scenarios.
This exception applies to areas where the separation is minimal but still provides adequate protection to occupants using the stairway.
Other Options Explained:
Option A (2 hour): Not required for this scenario.
Option C (1 hour): The wall may be 1 hour, but the openings need only ½ hour.
Option D (1 ½ hour): Exceeds the requirements.
Summary:
Openings must have a minimum ½-hour fire protection rating where the fire resistance-rated separation extends 10 feet from a set of stairs.