40 CFR 91.326 - Pre- and post-test analyzer calibration.
Calibrate the operating range of each analyzer used during the test prior to and after each test in accordance with the following procedure (A chronic need for parameter adjustment can indicate a need for instrument maintenance.):
(a) Make the calibration using a zero gas and a span gas whose nominal value is between 80 percent and 100 percent of full scale, inclusive, of the measuring range.
(b) Use the same analyzer(s) flow rate and pressure as that used during exhaust emission test sampling.
(1) Zero the analyzer using the appropriate zero gas. Adjust analyzer zero if necessary. Zero reading should be stable.
(2) Span the analyzer using the appropriate span gas for the range being calibrated. Adjust the analyzer to the calibration set point if necessary.
Title 40 published on 2014-07-01
no entries appear in the Federal Register after this date.