NR 440.24(2)(b)(b) “Sulfuric acid production unit” means any facility producing sulfuric acid by the contact process by burning elemental sulfur, alkylation acid, hydrogen sulfide, organic sulfides and mercaptans or acid sludge, but does not include facilities where conversion to sulfuric acid is utilized primarily as a means of preventing emissions to the atmosphere of sulfur dioxide or other sulfur compounds.

NR 440.24(3)(a)(a) On and after the date on which the performance test required to be conducted by s. NR 440.08 is completed, no owner or operator subject to the provisions of this section may cause to be discharged into the atmosphere from any affected facility any gases which contain sulfur dioxide in excess of 2.0 kg per metric ton of acid produced (4.0 lb per ton), the production being expressed as 100% H2SO4.

NR 440.24(4)(a)(a) On and after the date on which the performance test required to be conducted by s. NR 440.08 is completed, no owner or operator subject to the provisions of this section may cause to be discharged into the atmosphere from any affected facility any gases which:

NR 440.24(5)(a)(a) A continuous monitoring system for the measurement of sulfur dioxide shall be installed, calibrated, maintained and operated by the owner or operator. The pollutant gas used to prepare calibration gas mixtures under Performance Specification 2 of 40 CFR part 60, Appendix B, incorporated by reference in s. NR 440.17, and for calibration checks under s. NR 440.13 (4) shall be sulfur dioxide (SO2). Method 8 of 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17, shall be used for conducting monitoring system performance evaluations under s. NR 440.13 (3), except that only the sulfur dioxide portion of the Method 8 results shall be used. The span value shall be set at 1000 ppm of sulfur dioxide.

NR 440.24(5)(b)(b) The owner or operator shall establish a conversion factor for the purpose of converting monitoring data into units of the applicable standard (kg/metric ton, lb/ton). The conversion factor shall be determined, at a minimum, 3 times daily by measuring the concentration of sulfur dioxide entering the converter using suitable methods (e.g., the Reich test, National Air Pollution Control Administration Publication No. 999-AP-13) and calculating the appropriate conversion factor for each 8-hour period as follows:

NR 440.24(5)(c)(c) The owner or operator shall record all conversion factors and values under par. (b) from which they were computed (i.e., CF, r, and s).

NR 440.24(5)(d)(d) Alternatively, a source that processes elemental sulfur or an area that contains elemental sulfur and uses air to supply oxygen may use the following continuous emission monitoring approach and calculation procedures in determining SO2 emission rates in terms of the standard. This procedure is not required but is an alternative that would alleviate problems encountered in the measurement of gas velocities or production rate. Continuous emission monitoring systems for measuring SO2, O2 and CO2, if required, shall be installed, calibrated, maintained and operated by the owner or operator and subjected to the certification procedures in Performance Specifications 2 and 3 in Appendix B, 40 CFR part 60, incorporated by reference in s. NR 440.17 (1). The calibration procedure and span value for the SO2 monitor shall be as specified in par. (b). The span value for CO2, if required, shall be 10% and for O2 shall be 20.9% (air). A conversion factor based on process rate data is not necessary. Calculate the SO2 emission rate as follows: