40 CFR 86.1516 - Calibration; frequency and overview.
(a) Calibrations shall be performed as specified in §§ 86.1518-84 through 86.1526-84.
(b) At least monthly or after any maintenance which could alter calibration, check the calibration of the CO analyzer. Adjust or repair the analyzer as necessary.
(c) Water traps, filters, or conditioning columns should be checked before each test.