Two Group M occupancy buildings on one site- sprinklers? 2006 IBC 503.1.2 and 903.2.6

Two new retail buildings (M occupancy group) on one site (no interior property lines between, one ownership). The buildings are 10 ft apart.

Building 1 is 8,500 sf. Building 2 is 7,000 sf.

The buildings will be analyzed as portions of ONE building as allowed in Section 503.1.2 of the 2006 IBC (i.e. an assumed property line will NOT be used between the buildings).

Q1) If analyzed as portions of ONE building, does this mean the two buildings (combined area is 15,500 sf) will have to be sprinklered per Section 903.2.6 of the IBC? Do the combined Group M fire areas exceed 12,000 sf in this case, hence both buildings must be sprinklered? P.S.

Q2) If a sprinkler system is not desired for the buildings, is assuming a property line between the buildings the way to go, this way each building has a fire area that is less than 12,000 sf?

Thank you.
Original Post
Q1) No. You need to look at the definition of a fire area, which is the "aggregate floor area enclosed and bounded by fire walls, fire barriers, exterior walls or fire-resistance-rated horizontal assemblies of a building."

Since each building is enclosed by exterior walls, each building is considered a separate fire area. Therefore, no single fire area exceeds 12,000 sq. ft.

Q2) Sprinkler system is not required, and this option is not necessary because of response to Q1.
Q1) No, per the last sentence of 503.1.2: "The provisions of this code applicable to the aggregate building shall be applicable to each building." The commentary seeks only that the facing walls be constructed in accordance with Table 601 for exterior walls, but not Tables 602 or 704.8. Each building should otherwise be considered individually.
rlga_AZ is correct Wink

Since each building constitutes a separate fire area, and since each fire area is less than 12,000 sf, an automatic sprinkler system would not be required in either building even if the buildings were analyzed as portions of ONE building.

When analyzing as portions of ONE building, the buildings do not have to be protected from each other...i.e. you would not assume a property line and protect facing walls and openings, etc.
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