This part of IEC61207 applies to all aspects of analyzers utilizing TSLAS for the concentration measurement of one or more gas components in a gaseous mixture or vapour. It applies to analyzers utilizing tuneable semiconductor lasers as sources and utilizing absorption spectroscopy, such as direct absorption, FMS, WMS, multi-pass absorption spectroscopy, CRDS, ICOS, PAS and CEAS techniques, etc. It applies both to in situ or extractive type analyzers. This standard includes the following, it specifies the terms and definitions related to the functional performance of gas analyzers, utilizing tuneable semiconductor laser gas absorption spectroscopy, for the continuous measurement of gas or vapour concentration in a source gas, unifies methods used in making and verifying statements on the functional performance of this type of analyzers, specifies the type of tests to be performed to determine the functional performance and how to carry out these tests, provides basic documents to support the application of the standards of quality assurance with in ISO9001