CEN/TS 14793:2005
(Main)Stationary source emission - Intralaboratory validation procedure for an alternative method compared to a reference method
Stationary source emission - Intralaboratory validation procedure for an alternative method compared to a reference method
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 i
Emissionen aus stationären Quellen - Laborinterne Validierung von Alternativverfahren durch Vergleich mit einem Referenzverfahren
Der Zweck dieser Technischen Spezifikation ist die Festlegung eines Validierverfahrens zum Nachweis, ob ein Alternativverfahren (AM) an Stelle des Standardreferenzverfahrens (SRM) angewendet werden kann, die beide zur Bestimmung derselben Messgröße eingesetzt werden. Dieses Dokument richtet sich an Laboratorien, die mit der Messung von Luftverunreinigungen befasst sind (daher werden Beispiele aus diesem Bereich in den Anhängen dargestellt)
Diese Technische Spezifikation enthält insbesondere statistische Methoden und verschiedene Kriterien zur Bewertung des Alternativverfahrens. Das entbindet aber nicht die für diese Validierung verantwortliche Person von der Aufgabe, die Auswertung der verschiedenen Kriterien technisch und analytisch zu beurteilen.
Emissions de sources fixes - Méthode de validation intralaboratoire d'une méthode 'alternative' comparée à une méthode de référence
Emisije nepremičnih virov – Notranji laboratorijski postopki validacije alternativne metode v primerjavi z referenčno metodo
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2005
(PLVLMHQHSUHPLþQLKYLURY±1RWUDQMLODERUDWRULMVNLSRVWRSNLYDOLGDFLMHDOWHUQDWLYQH
PHWRGHYSULPHUMDYL]UHIHUHQþQRPHWRGR
Stationary source emission - Intralaboratory validation procedure for an alternative
method compared to a reference method
Emissionen aus stationären Quellen - Laborinterne Validierung von Alternativverfahren
durch Vergleich mit einem Referenzverfahren
Emissions de sources fixes - Méthode de validation intralaboratoire d'une méthode
'alternative' comparée a une méthode de référence
Ta slovenski standard je istoveten z: CEN/TS 14793:2005
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CEN/TS 14793
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
March 2005
ICS 13.040.40
English version
Stationary source emission - Intralaboratory validation procedure
for an alternative method compared to a reference method
Emissions de sources fixes - Méthode de validation Emissionen aus stationären Quellen -
intralaboratoire d'une méthode 'alternative' comparée à une Intralaborvalidierverfahren für ein Alternativverfahren
méthode de référence verglichen mit einem Referenzverfahren
This Technical Specification (CEN/TS) was approved by CEN on 1 March 2004 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 14793:2005: E
worldwide for CEN national Members.
page
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
3.1 General Vocabulary .6
3.2 Symbols .9
4 Contents of the validation.11
4.1 General.11
4.2 Description of the alternative method .11
4.3 Determination of performance characteristics.12
4.3.1 General.12
4.3.2 Manual method.12
4.3.3 Automatic method .12
4.4 Calculation of the overall uncertainty.13
4.5 In field validation.13
4.5.1 Coverage of in field validation.13
4.5.2 Evaluation of repeatability and non systematic deviation in relation to the reference
method .14
5 Summary of experiments performed.18
Annex A (informative) Example of measurement of repeatability and trueness of Thorin method
compared to Ion chromatography for SO measurement in stack.20
Annex B (informative) Statistical tables.27
B.1 Distribution of the Student probability function.27
B.2 Critical values for Grubbs test .29
Bibliography .30
Foreword
This document CEN/TS 14793:2005 has been prepared by Technical Committee CEN/TC 264 “Air quality”,
the secretariat of which is held by DIN.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Hungary Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway,
Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Annexes A and B are informative.
Introduction
Much has been published in the literature concerning method validation by collaborative study. CEN TC264
working groups try to follow these method validations when a new standard is prepared and the collaborative
study is probably the preferred way of carrying out the validation. However, it is not always a suitable option
for accredited laboratories. The application for which the method is required may be esoteric to the extent that
no other laboratories would be interested in collaboration. Those that might be interested can be competitors.
The present Technical Specification provides one of the possible methods of testing the equivalence of an
alternative method with a reference method.
1 Scope
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.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ENV 13005, Guide to the expression of uncertainly in measurement.
EN ISO 14956, Air quality – Evaluation of 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.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General Vocabulary
3.1.1
accepted reference value (see ENV 13005)
value which serves as an accepted reference value (or conventionally true value) of the sample, provided by
the arithmetic mean of the measurement values repeated according to the standard reference method (see
3.1.19)
3.1.2
alternative method (AM)
measurement method (3.1.15) which complies with the criteria given by this Technical Specification with
respect to the reference method (SRM)
NOTE An alternative analysis method can consist of a simplification of the reference method.
3.1.3
automatic measuring system (AMS)
measuring system interacting with one or several air quality characteristics and which returns an output signal
giving the measurement result expressed in the physical unit of such air quality characteristics
3.1.4
calibration
set of operations that establishes, under specified conditions, the systematic difference that may exist
between values of a measurand indicated by a measuring system and the corresponding values given by a
"reference" system represented by the reference materials and their accepted values (derived from VIM 6.11
and from ISO 11095:1996, clause 4)
NOTE 1 The result of a calibration permits either the assignment of values of the measurand to the indications or the
determination of corrections with respect to indications.
NOTE 2 A calibration may also determine other metrological properties such as the effect of influence quantities.
3.1.5
field of application of the measurement method
combination of the different types of matrix (3.1.12) and the range of concentrations of the measurand (3.1.14)
covered, to which the measurement method (3.1.15) is applied
NOTE As well as being an indication of all the satisfactory performance conditions for each factor, the field of
application of the measurement method can also include warnings concerning known interferences caused by other
components, or the inapplicability of certain matrices or conditions.
WARNING 1 The field of application of an alternative method can partially or completely cover the field of
application of the reference method. However, if it covers the fields of application of several reference
methods (horizontal method), several evaluations of each reference method shall be performed (e.g. Multi-
component measurement methods like FTIR).
WARNING 2 The definition of the field of application depends entirely upon the laboratory responsible for
the validation study and the knowledge acquired during the development of the method. It is sometimes
preferable to segment a field of application rather than to attempt to validate an overly general method. In this
case, a validation file for each field of application shall be compiled.
3.1.6
field repeatability conditions
the conditions in which independent test results are obtained by one laboratory using the same method
carried out through two measurement systems set up according a written procedure and measuring
simultaneously the concentration of the measurand
[ISO 5725-1:1994]
3.1.7
field reproducibility conditions
the conditions in which independent test results are obtained by at least two laboratories using the same
method carried out through two measurement systems set up according a written procedure and measuring
simultaneously the concentration of the measurand
[ISO 5725-1:1994]
3.1.8
lack of fit
systematic deviation within the range of application between the measurement result obtained by applying the
linear model equation to the observed re
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