40 CFR 60.166 - Test methods and procedures.
(a) In conducting performance tests required in § 60.8, the owner or operator shall use as reference methods and procedures the test methods in appendix A of this part or other methods and procedures as specified in this section, except as provided in § 60.8(b).
(2) The continuous monitoring system of § 60.165(b)(2) shall be used to determine the SO2 concentrations on a dry basis. The sampling time for each run shall be 6 hours, and the average SO2 concentration shall be computed for the 6-hour period as in § 60.165(c). The monitoring system drift during the run may not exceed 2 percent of the span value.