We compare the performance of an alternative method based on portable Fourier-transform infrared (FTIR) spectroscopy described in TGN M22, "Measuring Stack Gas Emissions Using FTIR Instruments," to the Standard Reference Methods (SRMs) for CO (EN 15058), NOx (EN 14792), SO₂(EN 14791), HCl (EN 1911), and H₂O (EN 14790). Testing was carried out using a Stack Simulator facility generating complex gas matrices of the measurands across concentration ranges of 0-75 mg m⁻³ and 0-100 mg m⁻³ CO, 0-200 mg m⁻³ and 0-300 mg m⁻³ NO, 0-75 mg m⁻³ and 0-200 mg m⁻³ SO₂, 0-15 mg m⁻³ and 0-60 mg m⁻³ HCl, and 0-14 vol% H₂O. The former values are the required monitoring range for each measurand as described in the European Union (EU) Industrial Emissions Directive (2010/75/EU) for waste incineration processes, and the latter are supplementary ranges representative of emissions from some large combustion plant processes. Test data were treated in accordance with CEN/TS 14793, and it was found that equivalency test criteria could be met across all concentration ranges with the exception of the NO supplementary range. The results demonstrated in principle where TGN M22/FTIR could be used in place of the existing SRMs to provide, as required under the Industrial Emissions Directive, annual validation/calibration of automated measuring systems (AMSs being permanently installed on industrial stacks to provide continuous monitoring of emissions to air). These data take a step toward the wider regulatory acceptance of portable FTIR providing the advantages of real-time calibration and quantification of all measurands on a single technique.