35 Ill. Adm. Code 283.240
Averaging Procedure
Section 283
Section 283.240 Averaging
Procedure
The following procedure shall be
used when averaging emissions tests results:
a) The average of the emissions tests results shall be determined
by the arithmetic average of three valid test run results, as long as the test
runs are conducted in conformance with either the provisions of an approved
test plan or with a test plan that has been modified in accordance with Section
283.230 of this Part.
b) Notwithstanding subsection (a) of this Section, if the owner
or operator of an emission unit elects to perform more than three test runs,
then the average shall be calculated based upon the results of all valid test
runs.
c) Notwithstanding subsection (a), in the event that a sample is
accidentally lost or conditions occur in which one of the test runs must be
discontinued because of forced shutdown, failure of an irreplaceable portion of
the sample train, extreme meteorological conditions, malfunction or other
dissimilar or non-representative circumstances, upon the owner's or operator's
documentation of the existence of any of the circumstances set forth in this
subsection (c) and verification by the Agency that the conditions existed,
compliance may be determined by using the arithmetic average of the test
results of all remaining valid test runs; however, a minimum of two valid test
runs is required to determine compliance.