The purpose of this Technical Specification is to specify a validation procedure to show if an Alternative Method (AM) can be used as an alternative to the Standard Reference Method (SRM), both implemented to determine the same measurand. This document has been drawn up for laboratories working in air pollution measurements (and consequently examples taken from this sector are included in the appendices).
In particular, this Technical Specification provides the statistical tools and different criteria to evaluate the alternative method; this does not release the person responsible for this validation from bearing technical and analytical judgement on the evaluation of the different criteria.
Three steps are described in the validation procedure:
⎯ description of the AM and setting of the field of equivalence (range and type of gas matrix);
⎯ determination of the performance characteristics of the AM and calculation of the overall uncertainty where appropriate and check of compliance of the maximum overall uncertainty allowed for the SRM;
⎯ check of repeatability and lack of systematic deviation of the AM in the field in comparison with the SRM for the type of matrix defined in the field of equivalence.
NOTE Some parts of the second step of the validation of the alternative method should be performed by a recognised test-house.
If the AM fulfils the requirement of the procedure, then the laboratory that carried out the whole validation process is allowed to use it as a SRM in the field application where the equivalence has been demonstrated.
However, if the validation process involves at least 4 different accredited laboratories performing simultaneously parallel measurements in the field, and if the AM passes with success all the tests of the procedure, then this method could be proposed to CEN, who can decide to consider this AM as a new reference method (ARM).
The use of this procedure implies that a reference method has been defined by the regulator or in a contract and has been validated.
This Technical Specification only considers the case of linear quantitative methods.
BS DD CEN/TS 14793:2005 Referenced Document
EN ISO 14956 Air quality - Evaluation of the suitability of a measurement procedure by comparison with a required measurement uncertainty ISO 14956: 2002
ISO 5725-2 Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method*， 2019-12-06 Update
BS DD CEN/TS 14793:2005 history
2017BS EN 14793:2017 Stationary source emissions. Demonstration of equivalence of an alternative method with a reference method
2006BS DD CEN/TS 14793:2005 Stationary source emission — Intralaboratory validation procedure for an alternative method compared to a reference method