(a) THC emission limit. Use Equation 6 to determine compliance with an emission limit for THC:

$$ Where, E = Emission rate of measured pollutant, kg/Mg (lb/ton) of feed; C = Measured volume fraction of pollutant, ppmv; MW = Molecular weight of measured pollutant, g/g-mole (lb/lb-mole): THC (as propane) = 44.11; Q = Volumetric flow rate of exhaust gases, dscm/hr (dscf/hr); K1 = Conversion factor, 1 kg/1,000 g (1 lb/lb); K2 = Conversion factor, 1,000 L/m 3 (1 ft 3/ft 3); Mv = Molar volume, 24.45 L/g-mole (385.3 ft 3/lb-mole); and P = Production rate, Mg/hr (ton/hr).

(b) PM, HCl, HF and D/F emission limits. (1) Use Equation 7 of this section to determine compliance with an emission limit for PM, HCl or HF:

Where: E = Emission rate of PM, HCl or HF, in kg/Mg (lb/ton) of feed; C = Concentration of PM, HCl or HF, in g/dscm (gr/dscf); Q = Volumetric flow rate of exhaust gases, in dscm/hr (dscf/hr); K1 = Conversion factor, 1 kg/1,000 g (1 lb/7,000 gr); and P = Production rate, in Mg/hr (ton/hr).

(2) Use Equation 7A of this section to determine compliance with an emission limit for D/F:

$$ Where: E = Emission rate of D/F, µg/Mg (gr/ton) of feed; C = Concentration of D/F, µg/dscm (gr/dscf); Q = Volumetric flow rate of exhaust gases, dscm/hr (dscf/hr); and P = Production rate, Mg/hr (ton/hr).

(c) HCl percent reduction standard. Use Equation 8 to determine compliance with an HCl percent reduction standard:

$$ Where, %R = Percent reduction of the control device; Li = Inlet loading of pollutant, kg/Mg (lb/ton); and Lo = Outlet loading of pollutant, kg/Mg (lb/ton).

(d) Conversion of D/F measurements to TEQ units. To convert D/F measurements to TEQ units, the owner or operator must use the procedures and equations in Interim Procedures for Estimating Risks Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and -Dibenzofurans (CDDs and CDFs) and 1989 Update, incorporated by reference see § 63.14.

(e) Secondary aluminum processing unit. Use the procedures in paragraphs (e)(1), (2), and (3) or the procedure in paragraph (e)(4) of this section to determine compliance with emission limits for a secondary aluminum processing unit.

(1) Use Equation 9 to compute the mass-weighted PM emissions for a secondary aluminum processing unit. Compliance is achieved if the mass-weighted emissions for the secondary aluminum processing unit (EcPM) is less than or equal to the emission limit for the secondary aluminum processing unit (LcPM) calculated using Equation 1 in § 63.1505(k).

Where: EcPM = The mass-weighted PM emissions for the secondary aluminum processing unit; EtiPM = Measured PM emissions for individual emission unit, or group of co-controlled emission units, i; Tti = The average feed rate for individual emission unit i during the operating cycle or performance test period, or the sum of the average feed rates for all emission units in the group of co-controlled emission units i; and n = The number of emission units, and groups of co-controlled emission units in the secondary aluminum processing unit.

(2) Use Equation 10 to compute the aluminum mass-weighted HCl or HF emissions for the secondary aluminum processing unit. Compliance is achieved if the mass-weighted emissions for the secondary aluminum processing unit (EcHCl/HF) is less than or equal to the emission limit for the secondary aluminum processing unit (LcHCl/HF) calculated using Equation 2 in § 63.1505(k).

Where: EcHCl/HF = The mass-weighted HCl or HF emissions for the secondary aluminum processing unit; and EtiHCl/HF = Measured HCl or HF emissions for individual emission unit, or group of co-controlled emission units i.

(3) Use Equation 11 to compute the aluminum mass-weighted D/F emissions for the secondary aluminum processing unit. Compliance is achieved if the mass-weighted emissions for the secondary aluminum processing unit is less than or equal to the emission limit for the secondary aluminum processing unit (LcD/F) calculated using Equation 3 in § 63.1505(k).

Where: EcD/F = The mass-weighted D/F emissions for the secondary aluminum processing unit; and EtiD/F = Measured D/F emissions for individual emission unit, or group of co-controlled emission units i.

(4) As an alternative to using the equations in paragraphs (e)(1), (2), and (3) of this section, the owner or operator may demonstrate compliance for a secondary aluminum processing unit by demonstrating that each existing group 1 furnace is in compliance with the emission limits for a new group 1 furnace in § 63.1505(i) and that each existing in-line fluxer is in compliance with the emission limits for a new in-line fluxer in § 63.1505(j).

(f) Periods of startup and shutdown. For a new or existing affected source, or a new or existing emission unit subject to an emissions limit in paragraphs § 63.1505(b) through (j) expressed in units of pounds per ton of feed/charge, or µg TEQ or ng TEQ per Mg of feed/charge, demonstrate compliance during periods of startup and shutdown in accordance with paragraph (f)(1) of this section or determine your emissions per unit of feed/charge during periods of startup and shutdown in accordance with paragraph (f)(2) of this section. Startup and shutdown emissions for group 1 furnaces and in-line fluxers must be calculated individually, and not on the basis of a SAPU. Periods of startup and shutdown are excluded from the calculation of SAPU emission limits in § 63.1505(k), the SAPU monitoring requirements in § 63.1510(t) and the SAPU emissions calculations in § 63.1513(e).

(1) For periods of startup and shutdown, records establishing a feed/charge rate of zero, a flux rate of zero, and that the affected source or emission unit was either heated with electricity, propane or natural gas as the sole sources of heat or was not heated, may be used to demonstrate compliance with the emission limit, or

(2) For periods of startup and shutdown, divide your measured emissions in lb/hr or µg/hr or ng/hr by the feed/charge rate in tons/hr or Mg/hr from your most recent performance test associated with a production rate greater than zero, or the rated capacity of the affected source if no prior performance test data are available.

[65 FR 15710, Mar. 23, 2000, as amended at 69 FR 53984, Sept. 3, 2004; 80 FR 56748, Sept. 18, 2015; 81 FR 38088, June 13, 2016]