This International Standard specifies the fundamental structure and the most important performance char­acteristics of automated measuring systems for ox­ides of nitrogen to be used on stationary source emissions, for example combustion plants. The pro­cedures to determine the performance characteristics are also specified. Furthermore, it describes methods and equipment to determine NO or NOx (NO + NO2) in flue gases including the sampling system and sample gas conditioning system. Dinitrogen monoxide (N2O) is not determined by the methods described in this International Standard. The given performance characteristics refer to the complete measuring sys­tem, from sampling to analyser.
This International Standard describes extractive and non-extractive systems in connection with a range of analysers that operate using, for example, the follow­ing principles:
- chemiluminescence;
- non-dispersive infrared spectroscopy;
- non-dispersive ultraviolet spectroscopy;
- differential optical absorption spectrometry.
NOTE 1 Commercial devices using the described tech­niques, that meet the requirements of this International Standard, are available.