This part of IEC 1207 applies to all aspects of analyzers using high-temperature electrochemical sensors for the measurement of oxygen in gas. It should be used in conjunction with IEC 1207-1. It applies to in-situ and extractive analyzers and to analyzers installed indoors and outdoors. The object of this part is: - to specify the terminology and definitions related to the functional performance of gas analyzers, utilizing a high-temperature electrochemical sensor, for the continuous measurement of oxygen concentration in a sample of 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, ISO 9002 and ISO 9003.