Sprinkler Trigger in a 12,000-Square-Foot Restaurant
A 12,000-square-foot Group A-2 restaurant is proposed in a one-story Type II-B building. The building has no automatic sprinkler system. A 6,000-square-foot Group B office is separated from the restaurant by a 1-hour fire partition. The applicant argues that the 1-hour separation creates a separate fire area for the restaurant and that the 12,000-square-foot area is below the allowable area for Type II-B construction, so no sprinkler is required. The building has open frontage on one side, and the applicant submits a code-analysis letter claiming an allowable area of 18,000 square feet. The restaurant has an occupant load of 800 and two remote exits. The inspector must determine whether the sprinkler trigger is based on allowable area or fire area and whether the 1-hour separation changes the result.
1. Is an automatic sprinkler system required in the A-2 restaurant? Explain the fire-area trigger.
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Yes. IBC Section 903.2.1.2 requires an automatic sprinkler system throughout a fire area containing a Group A-2 occupancy where the fire area exceeds 5,000 square feet. The restaurant is 12,000 square feet, so the fire area containing the A-2 occupancy exceeds the threshold. The applicant is confusing allowable building area under Chapter 5 with the sprinkler threshold. A large allowable area does not waive the sprinkler requirement. The inspector should cite the fire-area trigger and require sprinkler protection throughout the A-2 fire area, or require a design change that reduces the A-2 fire area to 5,000 square feet or less.
2. Does the 1-hour fire partition create a separate fire area that changes the sprinkler result?
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A fire area is the aggregate floor area enclosed by fire walls, fire barriers, exterior walls, or horizontal assemblies. A 1-hour fire barrier may bound a fire area, but it does not reduce the size of the restaurant itself. The A-2 fire area remains 12,000 square feet, which exceeds 5,000 square feet. The separation from the office may satisfy an occupancy-separation requirement, but it does not avoid the sprinkler trigger. To change the result, the applicant would need to create separate fire areas, each 5,000 square feet or less, using compliant fire barriers and providing egress from each area.
3. What compliant options remain if the owner refuses to install sprinklers?
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The owner can reduce the A-2 fire area to 5,000 square feet or less. That could be done by limiting the restaurant to 5,000 square feet and using the remaining area for a different occupancy, or by subdividing the restaurant into separate fire areas of 5,000 square feet or less with compliant fire barriers. Each resulting fire area must have adequate means of egress, and the barriers must be continuous and properly rated. The applicant must also verify occupancy separation, ventilation, and accessibility. Installing sprinklers is usually the least disruptive option because it preserves the open 12,000-square-foot layout and eliminates the need for additional fire barriers.