35 Ill. Adm. Code 203.1240
Nearby
Section 203.1240 Nearby
"Nearby", with respect to a specific structure or
terrain feature:
a) For purposes
of applying the formula provided in Section 203.1200(a)(2), means that distance
up to five times the lesser of the height or the width dimension of a
structure, but not greater than 0.8 km (½ mile); and
b) For
conducting demonstrations under Section 203.1200(a)(3), means not greater than
0.8 km (½ mile), except that a portion of a terrain feature may be considered
to be nearby if it falls within a distance of up to 10 times the maximum height
of the feature, not to exceed 2 miles if such feature achieves a height, 0.8 km
from the stack, that is at least 40 percent of the good engineering practice
stack height determined by the formula provided in Section 203.1200(a)(2)(B) or
26 meters, whichever is greater, as measured from the ground-level elevation at
the base of the stack. The height of the structure or terrain feature is
measured from the ground-level elevation at the base of the stack.