DIN EN 14791:2017-05

This European Standard specifies the standard reference method (SRM) for the determination of the sulphuric oxide SO2 in flue gases emitted to the atmosphere from ducts and stacks. It is based on a sampling system and two analytical principles: ion chromatography and the Thorin method. This European Standard specifies the performance characteristics to be determined and the performance criteria to be fulfilled by measuring systems based on the measurement method. It applies to periodic monitoring and to the calibration or control of automatic measuring systems (AMS) permanently installed on a stack, for regulatory or other purposes. This European Standard specifies criteria for demonstration of equivalence of an alternative method to the SRM by application of EN 14793:2017. This European Standard has been validated during field tests on waste incineration, co-incineration and large combustion installations. It has been validated for for sampling periods of 30 min in the range of 0,5 mg/m3 to 2 000 mg/m3of SO2 for an ion-chromatography variant and 5 mg/m3 to 2 000 mg/m3 of SO2 for the Thorin method according to emission limit values laid down in the Directive 2010/75/EU. The emission limit values of EU Directives are expressed in units of mg/m3 of SO2 on dry basis and at standard conditions of 273 K and 101,3 kPa. The revised version of EN 14791:2006 contains corrections and adaptations to newer standards. These include in particular: - Directive 2000/76/EC has been replaced by Directive 2010/75/EU; - the normative reference to EN 15259 regarding requirements for measurement sections and sites and for the measurement objective and plan has been included; - the definitions have been revised taking the definitions in EN 15259 into account and the new version of VIM (2012); - the detection limit has been deleted from the list of definitions and performance characteristics as repeatability at zero is more suitable; - the absorption efficiency of the first absorber is to be better than 95 % or the concentration of sulfate ion in the second absorber shall be less than the quantification limit (instead of the detection limit); - a reference to EN 15259 has been added to determine the homogeneity of the exhaust gas profile; - the equation of s_r has been refined; - the standard deviation sr,limit according to new rules specified in EN 14793 has been recalculated; - an estimate of the expanded uncertainty calculated through the determination of reproducibility has been included and has replaced the expression "reproducibility confidence interval"; - presentation of the calculation of the uncertainty budget has been improved; - the presentation of the equivalence of the chromatography method with the Thorin method has been improved to be in line with EN 14793; - a new annex on the calculation of uncertainty based on the concentration specification for dry gas and for oxygen reference conditions has been included. This standard is intended in particular for testing laboratories that use standard reference methods within the scope of periodic measurements, for plant operators and for supervisory authorities. This standard deals in particular with aspects of environmental protection and quality control in emission monitoring. The responsible committee for this standard is NA 134-04-01 AA "Emissionsmessverfahren" ("Emission measurement techniques") at DIN.