10.4 m 7.35 m 3.048r 7.35 m Visualize the same rolling sphere approaching the building from all possible directions. The locus of the sphere center at all sphere locations when it is just touching the building is the shape shown below (this is a TOP view). It is made of four linear segments and four quarter circles of radius 7.35 meters. The area of this shape is about 490 square meters - this is the exposed area for the lightning current of 1.5 kA