Group A-2: any one trigger
IBC 2021 Section 903.2.1.2 requires sprinklers for Group A-2 (restaurants, bars, banquet halls) where any one listed condition exists:
- The fire area exceeds 5,000 square feet (464 m²).
- The fire area has an occupant load of 100 or more.
Only one condition needs to be met. A 4,800-square-foot restaurant with exactly 100 occupants is sprinklered, because 100 meets "100 or more." Reading it as more than 100 is the common error. The area test works the other way: exactly 5,000 square feet does not trigger, because the fire area must exceed 5,000. The two figures are never combined: 4,999 square feet with 95 occupants triggers nothing.
Where the A-2 system goes
Section 903.2.1.2 requires sprinklers throughout stories containing the A-2 occupancy and throughout all stories from the A-2 occupancy to and including the levels of exit discharge serving it. A third-floor banquet hall with first-floor exit discharge means the third, second and first floors. The hall fire area alone, or the third floor alone, falls short. The rule runs down to exit discharge, not up to every story above.
A-1, M and S-1
- Group A-1, Section 903.2.1.1: fire area over 12,000 square feet or occupant load of 300 or more. The A-1 load figure is 300, not 500.
- Group M, Section 903.2.7: a single M fire area over 12,000 square feet, or the combined area of all M fire areas on all floors over 24,000 square feet.
- Group S-1, Section 903.2.9: the same thresholds as Group M.
The combined test catches multi-story stores. Three floors with 9,000-square-foot fire areas each total 27,000 square feet, which exceeds 24,000, so sprinklers are required even though no single fire area is over 12,000. A-1 shares the 12,000 figure but has no combined-floors test.
Group R: no threshold
Section 903.2.8 requires an automatic sprinkler system throughout all buildings with a Group R fire area. There is no size threshold, however small the apartment building. Any square-foot figure offered for Group R belongs to another group.