40 CFR § 60.74 - Test methods and procedures.
(a) In conducting the 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). Acceptable alternative methods and procedures are given in paragraph (c) of this section.
(1) The emission rate (E) of NOX shall be computed for each run using the following equation:
(2) Method 7 shall be used to determine the NOX concentration of each grab sample. Method 1 shall be used to select the sampling site, and the sampling point shall be the centroid of the stack or duct or at a point no closer to the walls than 1 m (3.28 ft). Four grab samples shall be taken at approximately 15-minute intervals. The arithmetic mean of the four sample concentrations shall constitute the run value (Cs).
(3) Method 2 shall be used to determine the volumetric flow rate (Qsd) of the effluent gas. The measurement site shall be the same as for the NOX sample. A velocity traverse shall be made once per run within the hour that the NOX samples are taken.
(4) The methods of § 60.73(c) shall be used to determine the production rate (P) of 100 percent nitric acid for each run. Material balance over the production system shall be used to confirm the production rate.
(1) For Method 7, Method 7A, 7B, 7C, or 7D may be used. If Method 7C or 7D is used, the sampling time shall be at least 1 hour.