Commercial Building Inspector B2General Administration, Permits, and PlansHard
A commercial building inspector is reviewing plans for a proposed new 5-story building classified as Group R-2 (residential apartments). The building is of Type III-A construction. The plans indicate that the floor finishes in the corridors and exit access stairways are proposed to be Class II interior floor finish materials. What is the maximum interior floor finish classification permitted in these areas, according to IBC Section 804.4?
- AClass II
- BNo restriction
- CClass III
- DClass I
Show answer & explanationAnswer & explanation
Correct answer: D. Class I
According to IBC Table 804.4, for Group R-2 occupancy, the interior floor finish in corridors and exit access stairways must be Class I. Therefore, Class II is not permitted in these areas.
Why the other options are wrong
- A. Class II is less restrictive than Class I and is not allowed in these high-traffic egress areas for Group R-2.
- B. Interior finishes in egress paths are heavily regulated for fire safety, so there are always restrictions.
- C. Class III has the highest flame spread and is not acceptable for these critical areas.
Interior Floor Finish Classification
Interior floor finishes are classified based on their critical radiant flux, which measures their resistance to flame spread under radiant heat, and these classifications dictate where they can be used within a building based on occupancy and location (e.g., egress paths).
- Class I: Highest resistance to flame spread (critical radiant flux ≥ 0.45 W/cm²).
- Class II: Moderate resistance (critical radiant flux ≥ 0.22 W/cm²).
- Classifications are critical for fire safety, especially in means of egress.
- Refer to IBC Table 804.4 for specific requirements by occupancy and location.
Memory trick: For 'Floor Finishes' in 'Egress', think 'Class' and 'Corridors' – higher 'Class' means safer 'Pass'.