DIN EN 14792:2017-05

This European Standard specifies the standard reference method (SRM) based on the chemiluminescence principle for the determination of the nitrogen oxides (NO_x) in flue gases emitted to the atmosphere from ducts and stacks. It includes the sampling and the gas conditioning system, as well as the analyser. This European Standard specifies the characteristics to be determined and the performance criteria to be fulfilled by portable automated measuring systems (P-AMS) based on this measurement method. It applies for periodic monitoring and for the calibration or control of automated 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. This European Standard has been validated during field tests on waste incineration, co-incineration and large combustion installations and on a recognized test-bench. It has been validated for sampling periods of 30 min in the range of 0 mg/m³ to 1 300 mg/m³ of NO_x for large combustion plants and 0 mg/m³ to 400 mg/m³ of NO_x for waste incineration, each measured as NO₂, according to emission limit values (ELV) laid down in the Directive 2010/75/EU. The ELV for NO_x (NO + NO₂ in EU Directives is expressed in mg/ m³ of NO₂ on a dry basis, at a specified value for oxygen and at standard conditions (273 K and 101,3 kPa). The revised version of EN 14792:2006 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 These include in particular: - Directive 2000/76/EC has been replaced by Directive 2010/75/EU; - the normative reference to EN 13284-1 has been replaced by EN 15259 regarding requirements for measurement sections and sites and for the measurement objective, plan and report; - the normative reference to EN 15267-4 regarding the minimum requirements and test procedures for portable automated measuring systems for monitoring emissions from stationary sources has been added; - 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 symbols and abbreviations used in the main section of the document have been included; - use of configuration 1 is avoided when the NO₂ concentration is more than 20 mg/m³; configuration 1 shall be ordinarily avoided when the NO₂/ NO_xratio is more than 25 %, unless it is demonstrated that the losses of NO2 have not been significant within the gas cooler; - the performance characteristics shall be determined in a general performance test according to the test procedures described in EN 15267-4 instead of the test procedures specified in EN 15267-3; - a reference to EN 15259 has been added to determine the homogeneity of the exhaust gas profile; - test gases shall have concentrations traceable to SI units; - an equation to calculate the concentration corrected when drift occurs has been included; - the expression of results has been modified to be in line with EN 15259; - 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"; - a new annex on the calculation of uncertainty based on the concentration specification for dry gas and for oxygen reference conditions has been included;- presentation of the calculation of the uncertainty budget has been improved; - typing errors in the table to determine the drift have been corrected. This standard is intended in particular for testing laboratories that use standard reference methods within the scope of periodic measurements, for manufacturers of corresponding measuring equipment, for testing institutes that conduct performance tests of such measuring equipment, for plant operators and for supervisory authorities. This draft 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.