Code of Massachusetts Regulations
780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS
Chapter 10 - Means of Egress
Section 1028 - ASSEMBLY
Subsection 1028.10 - Clear width of aisle accessways serving seating
Current through Register 1531, September 27, 2024
Where seating rows have 14 or fewer seats, the minimum clear aisle accessway width shall not be less than 12 inches (305 mm) measured as the clear horizontal distance from the back of the row ahead and the nearest projection of the row behind. Where chairs have automatic or self-rising seats, the measurement shall be made with seats in the raised position. Where any chair in the row does not have an automatic or self-rising seat, the measurements shall be made with the seat in the down position. For seats with folding tablet arms, row spacing shall be determined with the tablet arm in the used position.
Exception: For seats with folding tablet arms, row spacing is permitted to be determined with the tablet arm in the stored position where the tablet arm when raised manually to vertical position in one motion automatically returns to the stored position by force of gravity.
1028.10.1 Dual access. For rows of seating served by aisles or doorways at both ends, there shall not be more than 100 seats per row. The minimum clear width of 12 inches (305 mm) between rows shall be increased by 0.3 inch (7.6 mm) for every additional seat beyond 14 seats, but the minimum clear width is not required to exceed 22 inches (559 mm).
Exception: For smoke-protected assembly seating, the row length limits for a 12-inch-wide (305 mm) aisle accessway, beyond which the aisle accessway minimum clear width shall be increased, are in Table 1028.10.1.
TABLE 1028.10.1 SMOKE-PROTECTED ASSEMBLY AISLE ACCESSWAYS
| TOTAL NUMBER OF SEATS IN THE SMOKE- PROTECTED ASSEMBLY OCCUPANCY | MAXIMUM NUMBER OF SEATS PER ROW PERMITTED TO HAVE A MINIMUM 12-INCH CLEAR AISLE ACCESSWAY | |
| Aisle or doorway at both ends of row | Aisle or doorway at one end of row only | |
| Less than 4,000 | 14 | 7 |
| 4,000 | 15 | 7 |
| 7,000 | 16 | 8 |
| 10,000 | 17 | 8 |
| 13,000 | 18 | 9 |
| 16,000 | 19 | 9 |
| 19,000 | 20 | 10 |
| 22,000 and greater | 21 | 11 |
| For SI: 1 inch = 25.4 mm. |
1028.10.2 Single access. For rows of seating served by an aisle or doorway at only one end of the row, the minimum clear width of 12 inches (305 mm) between rows shall be increased by 0.6 inch (15.2 mm) for every additional seat beyond seven seats, but the minimum clear width is not required to exceed 22 inches (559 mm).
Exception: For smoke-protected assembly seating, the row length limits for a 12-inch-wide (305 mm) aisle accessway, beyond which the aisle accessway minimum clear width shall be increased, are in Table 1028.10.1.
