Residential Building Inspector B1Building Planning and Life SafetyHard
A residential building inspector is reviewing plans for a new three-story townhouse dwelling. The plans indicate that the interior walls separating individual townhouses will be constructed as fire separation walls. What is the minimum fire-resistance rating required for these walls?
- A1.5-hour fire-resistance rating
- B2-hour fire-resistance rating
- C3-hour fire-resistance rating
- D1-hour fire-resistance rating
Show answer & explanationAnswer & explanation
Correct answer: B. 2-hour fire-resistance rating
According to the 2021 IRC, Section R302.2, common walls between adjacent townhouses, which are considered separate buildings, are required to be 2-hour fire-resistance-rated. This is because they are essentially party walls serving as fire separation between distinct structures.
Why the other options are wrong
- A. 1.5-hour rating is not a standard IRC requirement for townhouse fire separation.
- C. 3-hour rating is typically for higher hazard occupancies or specific structural fire protection requirements, not standard townhouses.
- D. 1-hour rating is common for garage separations or walls to property lines at certain distances, but not between townhouses.
Townhouse Fire Separation Wall
A fire-resistance-rated wall that separates adjacent townhouse units, treated as separate buildings, to prevent fire spread between them.
- Required between each townhouse unit.
- Must extend from foundation to roof sheathing.
- Specified in IRC Section R302.2.
Memory trick: Townhouses need strong walls, two hours of fire protection, to stand apart.