Stack height limitations

(a) Stack height exclusion. Air quality modeling or ambient impact evaluation shall exclude the effect of that portion of the height of any stack which exceeds good engineering practice or the effect of any other dispersion techniques. (b) Determination of good engineering practice (GEP) stack height. GEP stack height shall be the greater of: (1) 65 meters, measured from the ground-level elevation at the base of the stack; or (2) The height under either OAC 252:100-8-1.5(b)(2)(A) or (B): (A) for stacks in existence on January 12, 1979 and for which the owner or operator had obtained all applicable permits or approvals required under OAC 252:100-8 or 40 CFR Part 52, Hg = 2.5H, provided the owner or operator can demonstrate that this equation was relied upon in establishing an emission limitation; (B) for all other stacks, Hg = H + 1.5L, where: (i) Hg = good engineering practice stack height, measured from the ground-level elevation at the base of the stack, (ii) H = height of nearby structure(s) measured from the ground-level elevation at the base of the stack, (iii) L = lesser dimension (height or projected width) of nearby structure(s), provided that the owner or operator may be required to verify such GEP stack height by the use of a field study or fluid model as the Executive Director shall determine; or (3) The height demonstrated by a fluid model or a field study approved by the reviewing agency, which ensures that the emissions from a stack do not result in excessive 12 concentrations of any air pollutant as a result of atmospheric downwash, wakes, or eddy effects created by the source itself, nearby structures, or nearby terrain features. (c) Nearby. (1) For the formulae in OAC 252:100-8-1. 5(b)(2). A structure or terrain feature shall be considered nearby if it is located within a distance of up to five times the lesser of the height or the width of a structure, but not more than 0.5 miles (0.8 km). (2) For demonstration in OAC 252:100-8-1. 5(b)(3). (A) A structure or terrain feature shall be considered nearby if located at a distance not greater than 0.5 mile (0.8 km), except that (B) A portion of a terrain feature may be considered nearby if: (i) It falls within a distance (not to exceed 2 miles) of up to 10 times the maximum height (Ht) of the feature, and (ii) At a distance of 0.5 mile, the height of such feature is at least 40 percent of the GEP stack height determined by the formulae provided in OAC 252:100-8- 1.5(b)(2)(B) or 85.3 feet (26 meters), whichever is greater, as measured from the base of the stack. (3) Measurement of height of structure or terrain. The height of the structure or terrain feature is measured from the ground-level elevation at the base of the stack. (d) Excessive concentrations. When utilized for the purpose of determining GEP stack height under OAC 252:100-8-1.5(b)(3), excessive concentrations shall be as follows: (1) For sources seeking credit for stack height exceeding that calculated under OAC 252:100-8-1.5(b)(2), a maximum ground-level pollutant concentration from a stack due in whole or part to downwash, wakes, and eddy effects produced by nearby structures or nearby terrain features which is at least 40 percent in excess of the maximum concentration experienced in the absence of such downwash, wakes, or eddy effects and which, when combined with the impacts due to all sources, produces a concentration in excess of ana national ambient air quality standard. For sources subject to the prevention of significant deterioration program (Part 7 of this Subchapter or Federal 40 CFR 52.21), the same criteria apply except that a concurrent exceedance of a prevention of significant deterioration increment is experienced. In making demonstrations under this part, the allowable emission rate shall conform to the new source performance standard that is applicable to the source category unless the owner or operator can demonstrate that this emission rate is infeasible. Where such demonstrations are approved by the Director, an alternative emission rate shall be established in consultation with the owner or operator; (2) For sources seeking credit after October l, 1983, for increases in existing stack heights up to the heights established under OAC 252:100-8-1.5(b)(2) either: (A) a maximum ground-level concentration due in whole or part to downwash, wakes or eddy effects as specified in OAC 252:100-8-1.5(b)(2), except that the emission rate specified by any applicable state implementation plan (or, in the absence of such a limit, the actual emission rate) shall be used, or (B) the actual presence of a local nuisance caused by the existing stack, as determined by the Director; and (3) For sources seeking credit after January 12, 1979 for a stack height determined under OAC 252:100-8-1.5(b)(2) where the Director requires the use of a field study or fluid model to verify GEP stack height, for sources seeking stack height credit after November 9, 1984 based on the aerodynamic influence of cooling towers, and for sources seeking 13 stack height credit after December 31, 1970 based on the aerodynamic influence of structures not adequately represented by the formulae in OAC 252:100-8-1.5(b)(2), a maximum ground-level concentration due in whole or part to downwash, wakes or eddy effects that is at least 40 percent in excess of the maximum concentration experienced in the absence of such downwash, wakes or eddy effects. PART 9. MAJOR SOURCES AFFECTING NONATTAINMENT AREAS