Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 204 - PREVENTION OF SIGNIFICANT DETERIORATION
Subpart B - DEFINITIONS
Section 204.420 - Good Engineering Practice
Current through Register Vol. 48, No. 38, September 20, 2024
a) "Good engineering practice", with respect to stack height, means the greater of:
Hg = 2.5 H,
provided the owner or operator produces evidence that this equation was actually relied on in establishing an emission limitation;
Hg = H + 1.5 L
where:
Hg = good engineering practice stack height, measured from the ground-level elevation at the base of the stack;
H = height of nearby structure or structures measured from the ground-level elevation at the base of the stack;
L = lesser dimension, height, or projected width of nearby structure or structures provided that USEPA or the Agency may require the use of a field study or fluid model to verify good engineering practice stack height for the source; or
b) For purposes of this definition, "stack" means any point in a source designed to emit solids, liquids, or gases into the air, including a pipe or duct but not including flares.