(i) Except as provided in paragraph (a)(3)(ii) of this section, uncontrolled HAP emissions from a process vent must be reduced by 98 percent or in accordance with any of the procedures in paragraphs (a)(1)(ii)(A) through (D) of this section if the uncontrolled HAP emissions from the vent exceed 25 tons per year, and the flow-weighted average flowrate (FRa) calculated using Equation 1 of this subpart is less than or equal to the flowrate index (FRI) calculated using Equation 2 of this subpart. View Image
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Where:
FRa = flow-weighted average flowrate for the vent, scfm
Di = duration of each emission event, min
FRi = flowrate of each emission event, scfm
n = number of emission events
FRI = flowrate index, scfm
HL = annual uncontrolled HAP emissions, lb/yr, as defined in § 63.1251