§  75.36 Missing data procedures for heat input determinations.

(a) When hourly heat input is determined using a flow monitoring system and a diluent gas (O2 or CO2) monitor, substitute data must be provided to calculate the heat input whenever quality assured data are unavailable from the flow monitor, the diluent gas monitor, or both. When flow rate data are unavailable, substitute flow rate data for the heat input calculation shall be provided according to §  75.31 or §  75.33, as applicable. On and after April 1, 2000, when diluent gas data are unavailable, the owner or operator shall provide substitute O2 or CO2 data for the heat input calculations in accordance with paragraphs (b) and (d) of this section. Prior to April 1, 2000, the owner or operator shall substitute for missing CO2 or O2 concentration data in accordance with either paragraphs (c) and (d) or paragraphs (b) and (d) of this section.

(b) During the first 720 quality assured monitor operating hours following initial certification (i.e., the date and time at which quality assured data begins to be recorded by the CEMS), or (for a previously certified CO2 or O2 monitor) during the 720 quality assured monitor operating hours preceding implementation of the standard missing data procedures in paragraph (d) of this section, the owner or operator shall provide substitute CO2 or O2 data, as applicable, for the calculation of heat input (under section 5.2 of appendix F to this part) according to §  75.31(b).

(c) Upon completion of the first 720 quality-assured monitor operating hours following initial certification of the CO2 (or O2) pollutant concentration monitor, the owner or operator shall provide substitute data for CO2 or O2 concentration to calculate heat input or shall substitute heat input determined under appendix F of this part according to the procedures in paragraphs (c)(1), (c)(2), or (c)(3) of this section. Upon completion of 2,160 quality-assured monitor operating hours following initial certification of the flow monitor, the owner or operator shall provide substitute data for volumetric flow according to the procedures in §  75.33 in order to calculate heat input, unless required to determine heat input using the fuel sampling procedures in appendix F of this part under paragraphs (c)(1), (c)(2) or (c)(3) of this section.

(1) Whenever a quality-assured monitor operating hour of CO2 or O2 concentration data has not been obtained and recorded for a period less than or equal to 72 hours or for a missing data period where the percent monitor data availability for the CO2 or O2 pollutant concentration monitor as of the last unit operating hour of the previous calendar quarter was greater than or equal to 90.0 percent, the owner or operator shall substitute the average of the recorded CO2 or O2 concentration for the hour before and the hour after the missing data period for each hour in each missing data period to calculate heat input.

(2) Whenever a quality-assured monitor operating hour of CO2 or O2 concentration data has not been obtained and recorded for a period of 72 consecutive unit operating hours or more, the owner or operator shall begin substituting heat input calculated using the procedures in section 5.5 of appendix F of this part beginning with the seventy-third hour of the missing data period until quality-assured CO2 or O2 concentration data are again available. The owner or operator shall use the CO2 or O2 concentration from the hour before the missing data period to substitute for hours 1 through 72 of the missing data period.

(3) Whenever no quality-assured CO2 or O2 concentration data are available for a period where the percent monitor data availability for the CO2 continuous emission monitoring system (or O2 diluent monitor) as of the last unit operating hour of the previous calendar quarter was less than 90.0 percent, the owner or operator shall substitute heat input calculated using the procedures in section 5.5 of appendix F of this part for each hour of the missing data period until quality-assured CO2 or O2 concentration data are again available.

(d) Upon completion of 720 quality-assured monitor operating hours using the initial missing data procedures of §  75.31(b), the owner or operator shall provide substitute data for CO2 or O2 concentration to calculate heat input, as follows. Substitute CO2 data for heat input determinations shall be provided according to §  75.35(d). Substitute O2 data for the heat input determinations shall be provided in accordance with the procedures in §  75.33(b), except that the term "O2 concentration" shall apply rather than the term "SO2 concentration" and the term "O2 diluent monitor" shall apply rather than the term "SO2 pollutant concentration monitor." In addition, the term "substitute the lesser of" shall apply rather than "substitute the greater of;" the terms "minimum hourly O2 concentration" and "minimum potential O2 concentration, as determined under section 2.1.3.2 of appendix A to this part" shall apply rather than, respectively, the terms "maximum hourly SO2 concentration" and "maximum potential SO2 concentration, as determined under section 2.1.1.1 of appendix A to this part;" and the terms "10th percentile" and "5th percentile" shall apply rather than, respectively, the terms "90th percentile" and "95th percentile" (see Table 1 of §  75.33).

[60 FR 26530, May 17, 1995, as amended at 64 FR 28604, May 26, 1999]