This part of IEC 61207 applies to all aspects of analyzers using photometric techniques for the measurement of concentration of one or more components in a mixture of gases or vapors. It should be used in conjunction with IEC 61207-1. For photometric analyzers utilizing tuneable semiconductor laser absorption spectroscopy (TSLAS) for gas measurements, IEC 61207-7 should also be referred to. This part of IEC 61207 applies to analyzers using non-dispersive and dispersive wavelength selection and using absorption, emission, wavelength derivative or scattering techniques. It applies to analyzers which receive either a conditioned or unconditioned sample of gas either under vacuum, at ambient pressure or pressurized. It applies to analyzers which measure gas concentrations directly within the sample gas. The object of this part is: – to specify the terminology and definitions related to the functional performance of gas analyzers, utilizing a photometric analyzer, for the continuous measurement of gas or vapor concentration in a source gas; – to unify methods used in making and verifying statements on the functional performance of such analyzers; – to specify what tests should be performed to determine the functional performance and how such tests should be carried out; – to provide basic documents to support the application of standards of quality assurance ISO 9001