This European Standard covers apparatus designed to measure flue gas parameters of heating appliances for domestic residential and commercial applications using commercially available fuels in compliance with metrological specification. The apparatus may consist of different functional modules that may be tested separately for complying with this standard and will be combined in different ways according to the different applications. Part 1 of EN 50379 specifies the general requirements and is supplemented by the requirements in EN 50379 2 and/or EN 50379 3. This European Standard specifies the performance requirements of portable spot reading apparatus designed to give a measurement of specific combustion flue gas parameters such as concentration of gaseous compounds, temperature and/or pressure to be used for testing the compliance with national regulations for the above mentioned appliances. This European Standard excludes apparatus for – continuous emission, safety monitoring and control, and – use in vessels with an international load line. NOTE 1 When this apparatus is used in industrial premises, national regulations should be observed. NOTE 2 Apparatus may contain functional modules that are not covered by this standard e.g. measurement of smoke spot number (see EN 267:2009+A1:2011, Annex A) and/or measurement of indoor ambient air (see EN 50543).