(a) Subsections (b), (c), and (d) of this section (emission specifications adopted by the Texas Air Control Board in 1972) apply in Fannin, Hood, and Palo Pinto Counties. This section no longer applies in Fannin and Hood Counties after the applicable final compliance date specified in §117.9300 of this title (relating to Compliance Schedule for Utility Electric Generation in East and Central Texas).
(b) No person shall allow emissions of nitrogen oxides (NOX ), calculated as nitrogen dioxide (NO 2), from any "opposed-fired" steam generating unit of more than 600,000 pounds per hour (lb/hr) maximum continuous steam capacity to exceed 0.7 pound per million British thermal units (lb/MMBtu) heat input, maximum two-hour average, at maximum steam capacity. An "opposed-fired" steam generating unit is defined as a unit having burners installed on two opposite vertical firebox surfaces.
(c) No person shall allow emissions of NO X , calculated as NO2, from any "front-fired" steam generating unit of more than 600,000 lb/hr maximum continuous steam capacity to exceed 0.5 lb/MMBtu heat input, maximum two-hour average, at maximum steam capacity. A "front-fired" steam generating unit is defined as a unit having all burners installed in a geometric array on one vertical firebox surface.
(d) No person shall allow emissions of NO X , calculated as NO2, from any "tangential-fired" steam generating unit of more than 600,000 lb/hr maximum continuous steam capacity to exceed 0.25 lb/MMBtu heat input, maximum two-hour average, at maximum steam capacity. A "tangential-fired" steam generating unit is defined as a unit having burners installed on all corners of the unit at various elevations.
(e) Existing gas-fired steam generating units of more than 600,000 lb/hr, but less than 1,100,000 lb/hr, maximum continuous steam capacity are exempt from the provisions of this section, provided the total steam generated from the unit during any one calendar year does not exceed 30% of the product of the maximum continuous steam capacity of the unit times the number of hours in a year. Written records of the amount of steam generated for each day's operation must be made on a daily basis and maintained for at least three years from the date of each entry. Such records must be made available upon request to representatives of the executive director, United States Environmental Protection Agency, or any local air pollution control agency having jurisdiction.

Source Note: The provisions of this §117.3005 adopted to be effective June 14, 2007, 32 TexReg 3206