§ 139.18. Calculation of alternative opacity limitations.
(a) The results of opacity measurements obtained by the technique specified in § 123.45 (relating to alternative opacity limitations) for the entire time period from the beginning of the first performance test to the end of the third performance test will be reduced to 1-minute averages.
(b) The 1-minute averages which correspond to each of the three performance tests will be used for calculation of the alternative opacity limits and treated as if they represented contiguous data.
(c) The highest 1-minute average as determined in subsection (b) is the alternative opacity limitation not to be exceeded at any time.
(d) The median value of the 1-minute averages as determined in subsection (b) is determined.
(e) One-minute averages equal to or less than the median value calculated in subsection (d) will be eliminated from calculations in subsections (f) and (g).
(f) The mean and modified 95% confidence interval shall be calculated for the remaining 1-minute averages as follows:
n
Xi X =i = l
n
Xi=individual 1-minute average n=number of individual 1-minute average (after elimination of averages less than or equal to the median value) C.I.m=modified 95% confidence interval
(g) The alternative opacity limitation not to be exceeded more than 3 minutes in any 1 hour shall be equal to the sum of the mean and the modified 95% confidence interval as calculated in subsection (f) (X + C.I.m,truncated to an integer % opacity.
(h) An hourly average opacity limitation not to be exceeded at any time will be calculated as follows:
(1) The 1-minute averages as determined in subsection (b) will be grouped in discrete hourly time periods starting with the beginning of the first performance test.
(2) A remaining 1-minute averages constituting less than a full hourly time period will be eliminated from calculations in paragraphs (3) and (4).
(3) The mean for each hourly time period will be calculated as follows:
60
60 where: X = mean Xi=individual 1-minute average(4) The hourly average opacity limitation not to be exceeded at any time shall be equal to the highest mean as calculated in paragraph (3) truncated to the nearest integer % opacity.
Source The provisions of this § 139.18 adopted June 19, 1981, effective June 20, 1981, 11 Pa.B. 2132.
Cross References This section cited in 25 Pa. Code § 123.45 (relating to alternative opacity limitations).
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