40 CFR § 1065.250 - Nondispersive infrared analyzer.
(a) Application. Use a nondispersive infrared (NDIR) analyzer to measure CO and CO2 concentrations in raw or diluted exhaust for either batch or continuous sampling.
(b) Component requirements. We recommend that you use an NDIR analyzer that meets the specifications in Table 1 of § 1065.205. Note that your NDIR-based system must meet the calibration and verifications in §§ 1065.350 and 1065.355 and it must also meet the linearity verification in § 1065.307.