Authority: IC 13-14-8-1; IC 13-14-9; IC 13-17-3-4

Affected: IC 13-17-3

Sec. 10. The owner or operator of a facility which is subject to the requirements of section 4 or section 8 of this rule shall demonstrate compliance with the applicable emissions limit(s) by one of the following methods:

(1) Installation of a permanent continuous emissions monitoring system for NOx, and if necessary, a diluent (carbon dioxide or oxygen). The permanent continuous emissions monitoring system shall meet the requirements of performance specification 2 and performance specification 3, 40 CFR Part 60, Appendix B* and quality assurance procedures contained in 40 CFR Part 60, Appendix F* or 40 CFR Part 75*.

(2) Performance of emission tests in accordance with U.S. EPA method 7, 7a, 7c, 7d, or 7e, and any additional approved U.S. EPA methods as applicable. Facilities conducting emissions tests in accordance with these methods shall meet the following requirements:

(A) The owner or operator shall obtain any additional:

(i) test data;

(ii) continuous diluent monitoring data, either carbon dioxide or oxygen; or

(iii) emission unit fuel usage or horsepower data;

concurrent with the compliance demonstration in order to convert the emission test results or monitoring data to the units of the applicable emissions limitation.

(B) Compliance demonstrations shall be performed while the affected facility is operating at, or as close to as possible, to its maximum permitted operating capacity.

(C) Compliance demonstrations must be representative of the normal operating modes, including fuel types or fuel blends employed, and shall exclude periods of:

(i) startup;

(ii) shutdown;

(iii) malfunction; and

(iv) low load operating conditions.

(3) For an affected facility without a permanent continuous emissions monitoring system in accordance with subdivision (1) of this section, installation of a temporary continuous emissions monitoring system for thirty (30) operating days that is capable of measuring and recording NOx and, if necessary, a diluent (carbon dioxide or oxygen) concentration in addition to calculating NOx lb/mmBtu data in an ongoing basis. Facilities that install a temporary continuous emissions monitoring system shall comply with the following:

(A) The temporary continuous emissions monitoring system shall be:

(i) installed;

(ii) calibrated;

(iii) maintained; and

(iv) operated in an approved manner and location where representative emissions measurements from the stack can be made.

(B) Prior to installation, the owner or operator shall submit a continuous emissions monitoring protocol that includes the location and specifications for each instrument or device, as well as procedures for:

(i) calibration;

(ii) operation;

(iii) data recording;

(iv) data evaluation; and

(v) data reporting.

(C) The temporary continuous monitoring system must meet the requirements of performance specification 2 and 3, as specified in 40 CFR Part 60, Appendix B*, and quality assurance procedures contained in 40 CFR Part 60, Appendix F, procedure 1*.

(D) The temporary continuous monitoring system must operate for a thirty (30) day period under normal operating modes. The thirty (30) days do not have to be consecutive.

(4) The owner or operator of a facility subject to this rule may request to monitor NOx emissions for compliance determination purposes using a predictive emission monitoring system in accordance with the requirements of 40 CFR 60, subpart A and appendix B, Performance Specification 16*, with written approval of the department, provided the facility is not otherwise required to operate a continuous emissions monitoring system under another legal authority.

*These documents are incorporated by reference. Copies may be obtained from the Government Publishing Office, www.gpo.gov, or are available for review at the Indiana Department of Environmental Management, Office of Legal Counsel, Indiana Government Center North, 100 North Senate Avenue, Thirteenth Floor, Indianapolis, IN 46204.

(Air Pollution Control Division; 326 IAC 10-7-10; filed Oct 27, 2025, 10:54 a.m.: 20251126-IR-326250204FRA)