Commercial Building Inspector B2Wall Construction and Wall CoveringsHard
A commercial building inspector is evaluating the fire-resistive integrity of a 2-hour rated fire wall separating two adjacent buildings. An opening is proposed in this fire wall for a conveyor system. What is the maximum aggregate area of openings permitted in a 2-hour fire wall in any 100 square feet of wall area?
- A50 square feet
- B150 square feet
- C120 square feet
- D100 square feet
Show answer & explanationAnswer & explanation
Correct answer: D. 100 square feet
According to IBC Section 706.8.2.2, for fire walls with a 2-hour fire-resistance rating, the maximum aggregate area of openings in any 100 square feet of wall area is 100 square feet. This means that a 2-hour fire wall can have up to 100% of its area in openings within a 100 square foot section, provided the individual opening requirements are met.
Why the other options are wrong
- A. 50 square feet is typically the maximum aggregate area for 3-hour or 4-hour fire walls.
- B. 150 square feet significantly exceeds the maximum permitted aggregate area for a 2-hour fire wall.
- C. 120 square feet exceeds the maximum permitted aggregate area for a 2-hour fire wall.
Fire Wall Opening Area Limit
The maximum aggregate area of openings permitted in a fire wall is limited by the wall's fire-resistance rating and is expressed as a percentage of the wall area.
- Limits are found in IBC Section 706.8.2.2.
- Higher fire ratings (3-hr, 4-hr) have smaller aggregate opening limits.
- Individual opening dimensions and fire door/shutter requirements must also be met.
Memory trick: Wall's Window Wisdom: Rating, Ratio, Restriction.