Commercial Building Inspector B2Public Safety and Special ConstructionMedium
A building inspector is reviewing the plans for a new public library (Group A-3) with a main reading room. The plans indicate a row of fixed seating with 15 chairs. According to IBC, what is the minimum required clear width for an aisle serving only one side of this fixed seating arrangement?
- A42 inches (1067 mm)
- B36 inches (914 mm)
- C48 inches (1219 mm)
- D44 inches (1118 mm)
Show answer & explanationAnswer & explanation
Correct answer: B. 36 inches (914 mm)
According to IBC Section 1029.8.1, the minimum clear width for aisles serving fixed seating is 36 inches (914 mm) where the aisle serves one side only. This is the base requirement, which can increase with occupant load, but for a single side and 15 chairs, 36 inches is the minimum.
Why the other options are wrong
- A. 42 inches is often a minimum for aisles serving both sides of fixed seating, or for larger occupant loads.
- C. 48 inches is typically for aisles with very large occupant loads or specific accessible route requirements.
- D. 44 inches is a common minimum for general corridors, not specifically for fixed seating aisles serving one side.
Aisle Width (Fixed Seating)
The clear width of aisles serving fixed seating must be sufficient for safe egress, determined by the number of seats and how the aisle is served.
- IBC Section 1029.8.1 specifies aisle widths.
- Width depends on serving one or both sides.
- Minimums increase with occupant load.
Memory trick: Aisle for seats: One side, 3 feet wide; both sides, more space required.