Fire Area determination for portable classroom buildings 3' apart but group as a single building on a site

[CalSchoolArchitect]

• FIRE AREA. The aggregate floor area enclosed and bounded by fire walls, fire barriers, exterior walls or horizontal assemblies of a building. Areas of the building not provided with surrounding walls shall be included in the fire area if such areas are included within the horizontal projection of the roof or floor next above."

I have (6) 960sf portable classroom buildings classroom buildings (type VB)(occ. classification E)(48 occ's/building)(288 total occ's) grouped as a single building on a site.
We are adding 1 additional 960 sf portable classroom building (total building area - 6,720sf)(total occ's 366)
Total combined building area < table 506.2 basic allowable area for typeVB-E occupancy (6720sf<9,500sf)
The school site is a pre-SB575 non-fully sprinklered school site.

DSA (the Division of the State Architect/California) states that with the new building addition, the fire area will consist of more that 300 occ's and that all the portable classroom buildings grouped together as a single building will be required to be sprinklered per 903.2.3.3. ... or the new building will need to be relocated 20' away from the original (6) buildings and treated as a separate building.
Are they correct?
The definition of fire area includes floor area "enclosed ... by exterior walls..." Would not each separate portable classroom building be classified as it's own separate fire area.
your help is appreciated.

 

[Jay Smith]

Fire areas would be defined by separations per 707.3.10, which requires a 2-hour fire barrier, or a width that allows for an imaginary lot line and fire separation distance on each side of it per 705.5. The occupant of >300 shows up in 903.2.3.3.

 

[steveray]

One building, one fire area (without fire barriers anyway).....If you exceed 903 you sprinkler....