Bldg A - Area Increase

(Eq 5-3)
Aa = [At + (NS × If)] 
where:
Aa = Allowable area (square feet). 
At = Tabular allowable area factor (NS, S13R or SM value, as applicable) in accordance with Table 506.2. [9500 s.f.]
NS = Tabular allowable area factor in accordance with Table 506.2 for a nonsprinklered building (regardless of whether the building is sprinklered). [9500 s.f.]
If = Area factor increase due to frontage (percent) as calculated in accordance with Section 506.3. [ 0.32 see calcs below)

(Eq 5-5)
If = [F/P - 0.25] x W/30 (Equation 5-5)
where:
If = Area factor increase due to frontage.
F = Building perimeter that fronts on a public way or open space having minimum distance of 20 feet (6096 mm).
P = Perimeter of entire building (feet). 
W = Width of public way or open space (feet) in accordance with Section 506.3.2.

Bldg A has 162’ that has 20ft of open space perpendicular to that side of the building.  Bldg A also has two (2) ends that measure 64 ft in length and each of these ends have 30 feet of open space perpendicular to them.

F= 162 ft + 64 ft + 64ft = 290 ft
P= width = 64 ft and length = 162 ft; perimeter = (64 x 2) + (162 x 2) = 452 ft
W = (162 x 20) + (64 x 30) + (64 x 30) = 7,080 / 290 = 24.4 ft (Weighted W)

Eq 5-5    If = [(290/452) – 0.25] x (24.4 / 30) = 0.32 or 32%
Eq 5-3     Aa = 9500 s.f + (9500 s.f x 0.32) = 12,540 s.f