Fire-Resistance Rating for Nonbearing Walls in Type IV Construction
Type IV (Heavy Timber) construction, as defined by the International Building Code (IBC) 2021, Section
602.4, consists of large, solid or laminated wood members.
Interior nonbearing walls and partitions in Type IV construction are not required to have a fire-resistance rating (0 hours) unless they separate different occupancies or are specifically mandated by another code provision.
2. Why Type IV Does Not Require a Rating for Nonbearing Walls
The heavy timber components inherently provide fire resistance due to their large cross-section, which chars on the surface and slows fire penetration.
IBC Table 601 confirms that interior nonbearing walls in Type IV construction do not have a required fire- resistance rating.
3. Verification of Other Options
Option B (1 hour) - Incorrect, as Type IV does not require a 1-hour rating for interior nonbearing walls unless specific conditions apply.
Option C (1-1/2 hours) - Incorrect, as there is no code requirement for this level of rating in Type IV nonbearing walls.
Option D (2 hours) - Incorrect, as Type IV walls are not rated unless separating occupancies.
Reference Sources:
International Building Code (IBC) 2021 - Section 602.4 (Type IV Construction Requirements) IBC Table 601 (Fire-Resistance Ratings for Building Elements) ICC Fire Inspector II Study Guide (2021)