BS/EN 14793-2017 pdf download.Stationary source emissions Demonstration of equivalence of an alternative method with a reference method.
— interferences;
— calibration procedure;
— reference materials.
5.3.3 Automatic method
Main sources of uncertainty for automated methods are attached to:
— response time;
— limit of detection and quantification;
— lack of fit;
— drift on a duration adapted to the measurement purpose;
— repeatability;
— dependence on sampling gas pressure;
— dependence on ambient temperature;
— dependence on voltage;
— interferences;
— leakage of the sampling line;
— absorption In the sampling system;
— adjustment of the analyser;
— reference material (e.g. calibration gas).
5.4 Calculation of the expanded uncertainty of the AM
The expanded uncertainty of the AM shall be calculated by building an uncertainty budget according to EN ISO 14956 or ISO/IEC Guide 98-3 (GUM). The maximum expanded uncertainty of the alternative method shall be compared with the reference’s and shall be lower or equal to the maximum expanded uncertainty specified by the reference method at the emission limit value.
5.5 DemonstratIon of equivalence In the field
5.5.1 Coverage of In field demonstration
5.5.1.1 General
The demonstration of equivalence in the field shall be performed at suitable plant(s). If necessary, a combination of two sets of data drawn from trials performed on plant(s) and on a test bench recognized by the competent authorities and meeting the requirements in Annex C may be used.
5.5.1.2 Gas matrixes
The in field demonstration” covers the field of application of the method defined under the sole responsibility of the test laboratory. In practice, it is the responsibility of the laboratory to demonstrate that the field of application of the method Is correctly covered, in terms of types of matrixes. The laboratory may determine the effect of each of the individual compounds present in the flue gases suspected to have an influence on the measurement result. Nevertheless, this experimental work in the laboratory cannot cover all the compounds that could interfere with the measurement results. Therefore, the possible effect of interferences shall be checked against the reference during experiment in the field by Implementing both methods In parallel. The laboratory shall find suitable plant(s), where the gas matrix containing high level of interfering gases of the stack gas exists. If the comparison with the reference method shows that the alternative method is valid and if there are no technical reasons against it, the transfer of the validity from this type of plant to other kinds of plants shall be made regular.
NOTE In the type approval or certification scheme for emission measurements, it is agreed that if the suitability of a method is demonstrated on a waste Incineration, then this suitability can be extended to other types of plants with different gas matrixes like combustion or co-combustion plants.
5.5.1.3 Concentration range
If the alternative method has shown in the laboratory an acceptable linearity (see 5.3) and expanded uncertainty (see 5.4) then the comparison in the field does not need to be carried out on the whole claimed concentration range where linearity has been checked. However, to be relevant, the statistical test for checking if there is no systematic deviation between AM and RM measurements, perform measurements In the field over all the claimed concentration range. At least 30 % of the total number of parallel measurements shall be performed in the lower 20 % of the range and at least 30% in the upper third of the range. Criteria of acceptance of the demonstration are given in 5.5.2.3.3.
To perform the demonstration and succeed to study a large concentration range, a combination of two sets of data drawn from trials performed on one or several plants of the same type can be accepted. An alternative might be to perform the comparison on a test bench recognized by the competent authorities to be able to generate the appropriate gas matrix.BS/EN 14793-2017 pdf download.