EN 14181:2014
(Main)Stationary source emissions - Quality assurance of automated measuring systems
Stationary source emissions - Quality assurance of automated measuring systems
This European Standard specifies procedures for establishing quality assurance levels (QAL) for automated measuring systems (AMS) installed on industrial plants for the determination of the flue gas components and other flue gas parameters.
This European Standard specifies:
- a procedure (QAL2) to calibrate the AMS and determine the variability of the measured values obtained by it, so as to demonstrate the suitability of the AMS for its application, following its installation;
- a procedure (QAL3) to maintain and demonstrate the required quality of the measurement results during the normal operation of an AMS, by checking that the zero and span characteristics are consistent with those determined during QAL1;
- a procedure for the annual surveillance tests (AST) of the AMS in order to evaluate (i) that it functions correctly and its performance remains valid and (ii) that its calibration function and variability remain as previously determined.
This European Standard is designed to be used after the AMS has been certified in accordance with the series of European Standards EN 15267.
Emissionen aus stationären Quellen - Qualitätssicherung für automatische Messeinrichtungen
Diese Europäische Norm legt Verfahren zur Einrichtung von Qualitätssicherungsstufen (QAL) für automatische Messeinrichtungen, die an industriellen Anlagen zur Ermittlung der Abgasbestandteile und weiterer Kenngrößen des Abgases installiert sind, fest.
Diese Europäische Norm legt fest:
- ein Verfahren (QAL2) zur Kalibrierung der automatischen Messeinrichtung und zur Ermittlung der Variabilität der damit ermittelten Messwerte, um so die Eignung der automatischen Messeinrichtung für ihre Anwendung nach dem Einbau nachzuweisen;
- ein Verfahren (QAL3) zur Aufrechterhaltung und Feststellung der geforderten Qualität der Messergebnisse während des normalen Betriebs der automatischen Messeinrichtung durch Überprüfung der Einhaltung der in QAL1 ermittelten Kenngrößen für den Nullpunkt und Referenzpunkt;
- ein Verfahren zur jährlichen Funktionsprüfung (AST) der automatischen Messeinrichtung zur Überprüfung, dass (i) die Messeinrichtung richtig arbeitet und ihre Leistung weiterhin ausreichend ist und (ii) ihre Kalibrierfunktion und Variabilität den zuvor ermittelten Kenngrößen entsprechen.
Diese Europäische Norm setzt voraus, dass die automatische Messeinrichtung zuvor nach den Europäischen Normen der Reihe EN 15267 zertifiziert wurde.
Émission des sources fixes - Assurance qualité des systèmes automatiques de mesurage
La présente Norme européenne spécifie des procédures qui seront mises en œuvre pour établir les niveaux d'assurance qualité (QAL) des systèmes automatiques de mesurage (AMS) installés dans les installations industrielles en vue du dosage des effluents gazeux et de la détermination des autres paramètres des effluents gazeux.
La présente Norme européenne spécifie :
- une procédure (QAL2) pour l'étalonnage de l'AMS et la détermination de la variabilité des valeurs mesurées par lui, dans le but de démontrer l'aptitude de l'AMS pour son application, après son installation ;
- une procédure (QAL3) pour le maintien et la démonstration de la qualité exigée des résultats de mesurage au cours du fonctionnement normal d'un AMS. Cela est réalisé par la vérification que les caractéristiques du zéro et de la sensibilité (gain) sont cohérentes avec celles déterminées durant QAL1 ;
- une procédure pour les tests annuels de surveillance (AST) de l'AMS afin d'évaluer (i) s'il fonctionne correctement, si ses performances restent valides et (ii) si sa fonction d'étalonnage et sa variabilité restent inchangées par rapport à leur détermination précédente.
La présente Norme européenne est destinée à être utilisée une fois que l'AMS est certifié conformément à la série de Normes européennes EN 15267.
Emisije nepremičnih virov - Zagotavljanje kakovosti avtomatskih merilnih sistemov
Ta evropski standard določa postopke za vzpostavitev ravni zagotavljanja kakovosti (QAL) za avtomatske merilne sisteme, nameščene v industrijskih obratih za ugotavljanje komponent dimnega plina in drugih parametrov dimnega plina.
Ta evropski standard določa:
– postopek (QAL2) za kalibriranje avtomatskega merilnega sistema in ugotavljanje variabilnosti z njim pridobljenih izmerjenih vrednosti, da se dokaže primernost avtomatskega merilnega sistema za uporabo po njegovi namestitvi;
– postopek (QAL3) za vzdrževanje in dokazovanje potrebne kakovosti rezultatov meritev med običajnim delovanjem avtomatskega merilnega sistema s preverjanjem, da so značilnosti ničelne točke in merilnega območja skladne z značilnostmi, ki so ugotovljene med postopkom QAL1;
– postopek za letne nadzorne teste (AST) avtomatskega merilnega sistema, s katerimi se oceni, (i) ali pravilno deluje in daje veljavne rezultate ter (ii) ali sta njegova funkcija kalibracije in variabilnost še vedno v stanju, kot je bilo predhodno ugotovljeno.
Ta evropski standard se uporablja po certifikaciji avtomatskega merilnega sistema v skladu z različnimi evropskimi standardi EN 15267.
Ta evropski standard je omejen na zagotavljanje kakovosti avtomatskih merilnih sistemov in ne vključuje zagotavljanja kakovosti zbirke podatkov in sistema za beleženje v obratu.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2015
1DGRPHãþD
SIST EN 14181:2004
(PLVLMHQHSUHPLþQLKYLURY=DJRWDYOMDQMHNDNRYRVWLDYWRPDWVNLKPHULOQLK
VLVWHPRY
Stationary source emissions - Quality assurance of automated measuring systems
Emissionen aus stationären Quellen - Qualitätssicherung für automatische
Messeinrichtungen
Émission des sources fixes - Assurance qualité des systèmes automatiques de mesure
Ta slovenski standard je istoveten z: EN 14181:2014
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 14181
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2014
ICS 13.040.40 Supersedes EN 14181:2004
English Version
Stationary source emissions - Quality assurance of automated
measuring systems
Émission des sources fixes - Assurance qualité des Emissionen aus stationären Quellen - Qualitätssicherung
systèmes automatiques de mesurage für automatische Messeinrichtungen
This European Standard was approved by CEN on 11 October 2014.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14181:2014 E
worldwide for CEN national Members.
Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Symbols and abbreviations . 10
5 Principle . 11
6 Calibration and validation of the AMS (QAL2) . 14
7 Ongoing quality assurance during operation (QAL3) . 24
8 Annual Surveillance Test (AST) . 30
9 Documentation . 34
Annex A (normative) QAL2 and AST functional test of AMS. 35
Annex B (normative) Test of linearity . 39
Annex C (informative) Control charts . 41
Annex D (normative) Documentation . 51
Annex E (informative) Examples of calculation of the calibration function and of the variability
test . 53
Annex F (informative) Example of calculation of the standard deviation s of the AMS at zero
AMS
and span level . 72
Annex G (informative) Example of using the calibration function and testing the variability and
validity of the calibration function in the AST . 75
Annex H (informative) Implementation of QAL1 . 80
Annex I (normative) k and t values . 81
v 0,95; N–1
Annex J (informative) Significant technical changes . 82
Bibliography . 84
Foreword
This document (EN 14181:2014) has been prepared by Technical Committee CEN/TC 264 “Air quality”, the
secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by May 2015 and conflicting national standards shall be withdrawn at the
latest by May 2015.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 14181:2004.
Annex J provides details of significant technical changes between this European Standard and the previous
edition.
The first edition of this document has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association to support requirements in the EU Directives
2000/76/EC [1] and 2001/80/EC [2], which have been replaced by EU Directive 2010/75/EU [3], and may also
be applicable for other purposes.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Introduction
This European Standard describes the quality assurance procedures needed to assure that an automated
measuring system (AMS) installed to measure emissions to air are capable of meeting the uncertainty
requirements on measured values given by legislation, e.g. EU Directives [1], [2], [3] or national legislation, or
more generally by competent authorities.
Three different quality assurance levels (QAL1, QAL2, and QAL3) are defined to achieve this objective. These
quality assurance levels cover the suitability of an AMS for its measuring task (e.g. before or during the
purchase period of the AMS), the validation of the AMS following its installation, and the control of the AMS
during its ongoing operation on an industrial plant. An annual surveillance test (AST) is also defined.
The suitability evaluation (QAL1) of the AMS and its measuring procedure are described in EN 15267-3 and
EN ISO 14956 where a methodology is given for calculating the total uncertainty of AMS measured values.
This total uncertainty is calculated from the evaluation of all the uncertainty components arising from its
individual performance characteristics that contribute.
1 Scope
This European Standard specifies procedures for establishing quality assurance levels (QAL) for automated
measuring systems (AMS) installed on industrial plants for the determination of the flue gas components and
other flue gas parameters.
This European Standard specifies:
— a procedure (QAL2) to calibrate the AMS and determine the variability of the measured values obtained
by it, so as to demonstrate the suitability of the AMS for its application, following its installation;
— a procedure (QAL3) to maintain and demonstrate the required quality of the measurement results during
the normal operation of an AMS, by checking that the zero and span characteristics are consistent with
those determined during QAL1;
— a procedure for the annual surveillance tests (AST) of the AMS in order to evaluate (i) that it functions
correctly and its performance remains valid and (ii) that its calibration function and variability remain as
previously determined.
This European Standard is designed to be used after the AMS has been certified in accordance with the
series of European Standards EN 15267.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 15259:2007, Air quality ― Measurement of stationary source emissions ― Requirements for
measurement sections and sites and for the measurement objective, plan and report
EN 15267-1, Air quality ― Certification of automated measuring systems ― Part 1: General principles
EN 15267-2, Air quality ― Certification of automated measuring systems ― Part 2: Initial assessment of the
AMS manufacturer’s quality management system and post certification surveillance for the manufacturing
process
EN 15267-3, Air quality ― Certification of automated measuring systems ― Part 3: Performance criteria and
test procedures for automated measuring systems for monitoring emissions from stationary sources
EN ISO 14956, Air quality ― Evaluation of the suitability of a measurement procedure by comparison with a
required measurement uncertainty (ISO 14956)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
automated measuring system
AMS
measuring system permanently installed on site for continuous monitoring of emissions or measurement of
peripheral parameters
Note 1 to entry: An AMS is a method which is traceable to a reference method.
Note 2 to entry: Apart from the analyser, an AMS includes facilities for taking samples (e.g. sample probe, sample gas
lines, flow meters, regulators, delivery pumps) and for sample conditioning (e.g. dust filter, water vapour removal devices,
converters, diluters). This definition also includes testing and adjusting devices that are required for regular functional
checks.
3.2
extractive AMS
AMS having the detection unit physically separated from the gas stream by means of a sampling system
3.3
in-situ AMS
AMS having the detection unit in the gas stream or in a part of it
3.4
peripheral AMS
AMS used to gather the data required to convert the AMS measured value to standard conditions
Note 1 to entry: A peripheral AMS is used to measure e.g. water vapour, temperature, pressure and oxygen.
3.5
reference method
RM
measurement method taken as a reference by convention, which gives the accepted reference value of the
measurand
[SOURCE: EN 15259:2007]
3.6
standard reference method
SRM
reference method prescribed by European or national legislation
Note 1 to entry: Standard reference methods are used e.g. to calibrate and validate AMS and for periodic
measurements to check compliance with limit values.
[SOURCE: EN 15259:2007]
3.7
peripheral SRM
SRM used to gather the data required to convert the SRM measured values to AMS or standard conditions
Note 1 to entry: A peripheral SRM is used to measure e.g. water vapour, temperature, pressure and oxygen.
3.8
standard conditions
conditions to which measured values have to be standardized to verify compliance with emission limit values
Note 1 to entry: Standard conditions are specified e.g. in EU Directives [1], [2] and [3].
3.9
emission limit value
ELV
limit value related to the maximum permissible uncertainty
Note 1 to entry: For the EU Directives [1], [2] and [3] it is the daily emission limit value that relates to the uncertainty
requirement.
3.10
maximum permissible uncertainty
uncertainty requirement on AMS measured values given by legislation or competent authorities
3.11
legislation
directives, acts, ordinances or regulations
3.12
competent authority
organization or organizations which implement the requirements of EU Directives and regulate installations
which shall comply with the requirements of this European Standard
3.13
calibration function
linear relationship between the values of the SRM and the AMS with the assumption of a constant residual
standard deviation
Note 1 to entry: For dust measuring AMS, a quadratic calibration function can be used as described in EN 13284-2.
3.14
standard deviation
positive square root of the mean squared deviation from the arithmetic mean divided by the number of
degrees of freedom
Note 1 to entry: The number of degrees of freedom is the number of measurements minus 1.
3.15
confidence interval
interval estimator (T , T ) for the parameter θ with the statistics T and T as interval limits and for which it
1 2 1 2
holds that P[T < θ < T ] ≥ (1 – α)
1 2
[SOURCE: ISO 3534-1:2006]
Note 1 to entry: The two-sided 95 % confidence interval of a normal distribution is illustrated in Figure 1, where:
T = Θ – 1,96 σ is the lower 95 % confidence limit;
1 0
T = Θ + 1,96 σ is the upper 95 % confidence limit;
2 0
I = T – T = 2 × 1,96 × σ is the length of the 95 % confidence interval;
2 1 0
σ = I / (2 × 1,96) is the standard deviation associated with a 95 % confidence interval;
n is the number of observed values;
f is the frequency;
m is the measured value.
Figure 1 — Illustration of the 95 % confidence interval of a normal distribution
In this European Standard, the standard deviation σ is estimated in QAL2 by parallel measurements with the SRM. It is
assumed that the requirement for σ , presented in terms of a maximum permissible uncertainty, is provided by the
regulators (e.g. in some EU Directives). In the procedures of this standard, the premise is that the maximum permissible
uncertainty is given as σ itself, or as a quarter of the length of the full 95 % confidence interval.
Note 2 to entry: In some EU Directives (see [1], [2], [3]) the uncertainty of the AMS measured values is expressed as
half of the length of a 95 % confidence interval as a percentage P of the emission limit value E. Then, in order to convert
this uncertainty to a standard deviation, the appropriate conversion factor is σ = P E / 1,96 .
3.16
variability
standard deviation of the differences of parallel measurements between the SRM and AMS
3.17
uncertainty
parameter associated with the result of a measurement that characterises the dispersion of the values that
could reasonably be attributed to the measurand
[SOURCE: ISO/IEC Guide 98-3:2008]
3.18
measurand
particular quantity subject to measurement
[SOURCE: ISO/IEC Guide 98-3:2008]
Note 1 to entry: A measurand can be e.g. the mass concentration of a measured component or the waste gas velocity,
pressure or temperature.
3.19
measured component
constituent of the waste gas for which a defined measurand is to be determined by measurement
[SOURCE: EN 15259:2007]
3.20
peripheral parameter
specified physical or chemical quantity which is needed for conversion of measured values to specified
conditions
3.21
measured value
estimated value of the measurand derived from a measured signal
Note 1 to entry: This usually involves calculations related to the calibration process and conversion to required
quantities.
Note 2 to entry: A measured value is a short-term average. The averaging time can be e.g. 10 min, 30 min or 1 h.
3.22
instrument reading
measured signal directly provided by the AMS without using the calibration function
3.23
zero reading
instrument reading on simulation of the input parameter at zero concentration
3.24
span reading
instrument reading for a simulation of the input parameter at a fixed elevated concentration.
3.25
instability
change in the measured signal comprised of drift and dispersion over a stated maintenance interval
Note 1 to entry: Drift and dispersion specify the monotonic and stochastic change with time of the measured signal,
respectively.
3.26
drift
monotonic change of the calibration function over stated maintenance interval, which results in a change of
the measured signal
3.27
precision
closeness of agreement of results obtained from the AMS for successive zero readings and successive span
readings at defined time intervals
3.28
response time
t
time interval between the instant of a sudden change in the value of the input quantity to an AMS and the time
as from which the value of the output quantity is reliably maintained above 90 % of the correct value of the
input quantity
Note 1 to entry: The response time is also referred to as the 90 % time.
3.29
maintenance interval
maximum admissible interval of time for which the performance characteristics will remain within a predefined
range without external servicing, e.g. refill, calibration, adjustment
3.30
reference material
substance or mixture of substances, with a known concentration within specified limits, or a device of known
characteristics
3.31
CUSUM chart
calculation procedure in which the amount of drift and change in precision is compared to the corresponding
uncertainty components which are obtained during QAL1
3.32
EWMA chart
calculation procedure in which the combined amount of drift and change in precision is compared to the
corresponding uncertainty components which are obtained during QAL1
Note 1 to entry: The EWMA chart averages the data in a way that gives less and less weight to data as they are
further removed in time.
4 Symbols and abbreviations
4.1 Symbols
a
intercept of the calibration function
best estimate of a
aˆ
slope of the calibration function
b
ˆ
best estimate of b
b
ˆ
D difference between SRM measured value y and calibrated AMS measured value y
i i i
average of D
D
i
E emission limit value
test value for variability (based on a χ -test, with a β-value of 50 %, for N numbers of paired
k
v
measurements)
N number of paired samples in parallel measurements
P percentage value
s standard deviation of the AMS used in QAL3
AMS
s
standard deviation of the differences D in parallel measurements
D i
t value of the t distribution for a significance level of 95 % and a number of degrees of
0,95; N–1
freedom of N – 1
u uncertainty due to instability (expressed as a standard deviation)
inst
u uncertainty due to influence of temperature (expressed as a standard deviation)
temp
u uncertainty due to influence of pressure (expressed as a standard deviation)
pres
u uncertainty due to influence of voltage (expressed as a standard deviation)
volt
u
any other uncertainty that may influence the zero and span reading (expressed as a
others
standard deviation)
th
x i measured signal obtained with the AMS at AMS measuring conditions
i
x
average of AMS measured signals x
i
th
i measured value obtained with the SRM
y
i
y average of the SRM measured values y
i
SRM measured value y at standard conditions
i
y
i,s
lowest SRM measured value at standard conditions
y
s,min
highest SRM measured value at standard conditions
y
s,max
yˆ best estimate for the ”true value”, calculated from the AMS measured signal x by means of
i i
the calibration function
yˆ best estimate for the ”true value”, calculated from the AMS measured signal x at standard
i,s i
conditions
best estimate for the ”true value”, calculated from the maximum value of the AMS measured
yˆ
s,max
signals x at standard conditions
i
Z offset (the difference between the AMS zero reading and the zero)
α significance level
ε deviation between y and the expected value
i i
standard deviation associated with the uncertainty derived from requirements of legislation
σ
4.2 Abbreviations
AMS automated measuring system
AST annual surveillance test
CUSUM cumulative sum
DAHS data acquisition and handling system
ELV emission limit value
EWMA exponentially weighted moving-average
QA quality assurance
QAL quality assurance level
QAL1 first quality assurance level
QAL2 second quality assurance level
QAL3 third quality assurance level
QC quality control
SRM standard reference method
5 Principle
5.1 General
An AMS to be used at installations shall have been proven suitable for its measuring task (parameter and
composition of the flue gas) by use of the QAL1 procedure, as specified by EN 15267-1 EN 15267-2,
EN 15267-3 and EN ISO 14956. Using these standards, it shall be proven that the total uncertainty of the
results obtained from the AMS meets the specification for uncertainty stated in the applicable regulations. In
QAL1 the total uncertainty required by the applicable regulation is calculated by summing in an appropriate
manner all the relevant uncertainty components arising from the individual performance characteristics.
In case of new installations of AMS, the AMS shall have been certified in accordance with EN 15267-1,
EN 15267-2, and EN 15267-3.
In case of AMS already installed at plants which have not been certified according to EN 15267-1, EN 15267-
2, and EN 15267-3, or AMS already installed at plants which were certified according to EN 15267-1,
EN 15267-2, and EN 15267-3 but where the ELV and the uncertainty requirement have subsequently
changed, the procedure described in H.2 may be applied. However, H.2 does not apply to new installations of
old AMS which have not been certified according to EN 15267-1, EN 15267-2 and EN 15267-3.
NOTE 1 SRM measurements, influences by peripheral parameters and the sampling site can contribute to the
uncertainty of the AMS measured values determined in QAL2.
NOTE 2 EN 15267-3 requires that the total uncertainty of the AMS measured values determined in the performance
test should be at least 25 % below the maximum permissible uncertainty specified e.g. in applicable regulations to provide
a sufficient margin for the uncertainty contributions from the individual installation of the AMS to pass QAL2 and QAL3
successfully.
The QAL2 and AST procedures involve testing laboratories, whereas the QAL3 procedures involve the plant
operators.
QAL2 is a procedure for the determination of the calibration function and its variability, and a test of the
variability of the measured values of the AMS compared with the maximum permissible uncertainty given by
legislation. The QAL2 tests are performed on suitable AMS that have been correctly installed and
commissioned. A calibration function is established from the results of a number of parallel measurements
performed with the standard reference method (SRM). The variability of the measured values obtained with
the AMS is then evaluated against the maximum permissible uncertainty.
The QAL2 procedures are repeated periodically, after a major change of plant operation, after a failure of the
AMS or as required by legislation.
QAL3 is a procedure which is used to check drift and precision in order to demonstrate that the AMS is in
control during its operation so that it continues to function within the required specifications for uncertainty.
This is achieved by conducting periodic zero and span checks on the AMS – based on those used in the
procedure for zero and span repeatability tests carried out in QAL1 – and then evaluating the results obtained
using control charts. Zero and span adjustments or maintenance of the AMS, may be necessary depending on
the results of this evaluation.
The AST is a procedure which is used to evaluate whether the uncertainty of the measured values obtained
from the AMS still meet the uncertainty criteria – as demonstrated in the previous QAL2 test. It also
determines whether the calibration function obtained during the previous QAL2 test is still valid. The validity of
the measured values obtained with the AMS is checked by means of a series of functional tests as well as by
the performance of a limited number of parallel measurements using an appropriate SRM.
NOTE 3 There are several concentration ranges relevant to the application of this European Standard:
• certification range
This is the range over which the AMS has been certified. It is generally recommended that this range be related to the ELV
given in relevant EU Directives of the processes under which the AMS will be used. EN 15267-3 requires that the
certification range be no greater than 1,5 times the daily ELV for waste incineration plants and 2,5 times the daily ELV for
large combustion plants. Where there is a choice, the daily ELV is used.
• calibration range
This is the range over which the AMS has been calibrated under the QAL2 procedure.
• measuring range
This is the range at which the AMS is set to operate during use. There are usually requirements from national competent
authorities that the range encompasses the maximum short-term ELV. The measuring range can be greater than the
certification range.
5.2 Limitations
Figure 2 illustrates the components of the AMS covered by this standard.
Figure 2 — Limits for the QA of the AMS excluding the data acquisition and handling system
NOTE 1 The influence of the uncertainty of the measurement results, which arise from the data acquisition and
handling system of the AMS or of the plant system, and its determination, are not covered by this standard.
NOTE 2 The performance of the data acquisition and handling system (DAHS) can be as influential as the AMS
performance in determining the quality of the results obtained from the whole measuring system/process. There are
different requirements for data collection, recording and presentation in different countries. A European Standard on
quality assurance of DAHS is currently under preparation.
When conducting parallel measurements, the measured signals from the AMS shall be taken directly from the
AMS (e.g. expressed as analogue or digital signal) during the QAL2 and AST procedures specified in this
standard, by using an independent data collection system provided by the organisation(s) carrying out the
QAL2 and AST tests. All data shall be recorded in their uncorrected form (without corrections e.g. for
temperature and oxygen). A plant data collection system with ongoing quality control can alternatively be used
to collect the measured signal from the AMS.
5.3 Measurement site and installation
The AMS shall be installed in accordance with the requirements of the relevant European and/or international
standards. Special attention shall be given to ensure that the AMS is readily accessible for regular
maintenance and other necessary activities.
The AMS should be positioned as far as practical in a position where it measures a sample that is
representative of the stack gas composition. EN 15259 describes a procedure to identify the best sampling
location for the AMS, in order to provide representative measurements. It also defines the optimum location
for undertaking parallel SRM measurements for the QAL2.
All measurements shall be carried out on a suitable AMS and peripheral AMS installed within an appropriate
working environment.
The working platform used to access the AMS and the working platform used to perform the SRM
measurements shall be in accordance with the requirements of EN 15259. The sampling ports for
measurements with the SRM shall be placed in such a location to avoid mutual interference between SRM
and AMS in order to achieve comparable measurements between AMS and SRM.
NOTE Lack in the fulfilment of these conditions can result in higher measurement uncertainties, potentially resulting
in nonconformity with the requirements given by EU Directives.
It is necessary to have good access to the AMS to enable inspections to take place and also to minimize the
time taken to implement the quality assurance procedures of this standard. A clean, well-ventilated and well-lit
working space around the AMS is required to enable the staff to perform this work effectively. Suitable
protection is required for the personnel and the equipment, if the working platform is exposed to the weather.
5.4 Testing laboratories performing SRM measurements
The testing laboratories performing the measurements with the SRM shall be accredited for this task
according to EN ISO/IEC 17025, or shall be approved directly by the relevant competent authority.
NOTE CEN/TS 15675 provides clarification and additional information on the application of EN ISO/IEC 17025 to
periodic measurements used e.g. for the calibration of AMS.
6 Calibration and validation of the AMS (QAL2)
6.1 General
QAL2 covers the following items:
— functional test of the AMS including check of correct installation;
— parallel measurements with the SRM;
— data evaluation;
— determination of the calibration function of the AMS and its range of validity;
— calculation of variability of the AMS measured values;
— test of variability of the AMS measured values;
— reporting.
The sequence of the combined tests is shown in Figure 3.
Figure 3 — Flow diagram for the calibration and variability tests
A QAL2 procedure shall be performed for all measurands:
— at least every 5 years for every AMS or more frequently if so required by legislation or by the competent
authority;
Furthermore, a QAL2 shall be performed for all the measurands influenced by:
— any major change in plant operation (e.g. change in flue gas abatement system or change of fuel), or
— any major changes or repairs to the AMS, which will influence the results obtained significantly.
The results of QAL2 shall be implemented within six months after the changes. During the period before a
new calibration function has been established the previous calibration function (where necessary with
extrapolation) shall be used.
NOTE In some EU member countries the local authorities allow in individual cases the continued use of the previous
calibration function if it can be proven by use of a specified statistical procedure that the new calibration function does not
significantly differ from the previous one.
Examples of calculation of the calibration function and of the variability test are given in Annex E.
6.2 Functional test
The requirements for installation and the measurement site as specified in 5.3 shall be fulfilled.
Before calibration (see 6.3 and 6.5) and the test for variability (see 6.6 and 6.7) are performed, it shall be
proven that the AMS is commissioned satisfactorily, e.g. as specified by the AMS supplier and/or
manufacturer. It shall also be shown and documented that the AMS gives a zero reading on a zero
concentration.
NOTE For some AMS it is difficult to achieve a zero reading. In those situations, the AMS can be removed from the
stack, and zeroed using a test bench or similar. As an alternative, a measuring path, which enables this zero test to be
carried out, can be installed in the stack.
The functional test before calibration shall be performed according to Annex A. It is recommended to perform
the functional test not more than one month before parallel measurements are started. The functional test
shall be performed by an experienced testing laboratory, which has been recognised by the competent
authority.
The specific precautions to be taken should depend on the individual location. Special attention should be
made for particulate measurements.
Since the AMS and SRM measured values are converted to standard conditions by independently determined
data sets of the peripheral parameters, the uncertainties in the peripheral parameters are attributed to the
AMS of the air pollutant in the variability test. Therefore, it is recommended to perform the relevant steps of
the functional test specified in Annex A for measuring systems of the peripheral parameters to minimize
uncertainties caused by the peripheral parameters.
6.3 Parallel measurements with the SRM
Parallel measurements shall be performed with the AMS and SRM in order to calibrate and validate the AMS
by use of an independent method.
It is not sufficient to use reference materials alone to obtain the calibration functions and this is therefore not
permitted. This is because these reference materials do not replicate sufficiently the matrix stack gas, they
cannot be used to establish that the sampling point(s) of the AMS are representative, and they are not used
with the sampling system in all cases. However, if there are limited variations in the results obtained in the
AMS/SRM tests, and the measured concentrations are well below the ELV, an extrapolation of the calibration
function to the ELV may be verified by the use of appropriate reference materials, taking into account the
effects of interfering substances on the AMS, where appropriate.
If clear and distinct operating modes of the plant process are part of its normal operation (for example
changes of fuel), additional calibrations shall be performed and a calibration function established for each
operational mode.
NOTE 1 It can be possible to establish one calibration function fulfilling the variability requirements that covers the
range of conditions within which the plant operates.
In order to ensure that the calibration function is valid for the range of conditions within which the plant will
operate, the concentrations during the calibration shall be varied as much as possible within the normal
operations of the plant. This shall ensure that the calibration of the AMS is valid over as large a range as
possible, and also that it covers most operational situations.
NOTE 2 Careful measurement planning can identify the optimum time for the parallel measurements, when the
emissions are at their highest or most varied.
The test for variability shall be performed (see 6.7) for each calibration function, i.e. for each operating mode
of the plant.
The SRM shall be used to sample the emissions at a sampling plane in the duct, which fulfils the requirements
of EN 15259, and is as close as possible to the AMS.
The presence of the SRM equipment shall not influence or disturb the AMS measurements and vice versa.
NOTE 3 Although EN 15259 allows simplified sampling of gaseous components in cases of homogeneous flue gas or
negligible concentration variations, grid measurements can improve the quality of the calibration curve.
For each calibration a minimum of 15 valid parallel measurements shall be made with the plant operating
normally. These measurements shall be uniformly spread both over at least three days and over each of the
measuring days of normally 8 h to 10 h (e.g. not five measurements in the morning and none in the afternoon)
and be performed within a period of four weeks.
NOTE 4 The required spread of a minimum of 15 valid measurements over three days is essential in minimizing the
effect of influences of the subsequent measurement results (i.e. to avoid auto-correlation between the calculated
differences in the results of the AMS and SRM). The alternative of performing more measurements within a shorter time
interval can lead to the establishment of an invalid calibration function.
NOTE 5 A minimum of 15 valid measurements can in practice require that more than 15 samples be taken, since some
samples may be deemed to be invalid during subsequent analysis because of inadequate quality.
NOTE 6 The requirement that the measurements need to be uniformly spread over at least three days does not imply
that the measurements need to be performed within three consecutive days.
If the QAL2 is not the first QAL2 being carried out on the AMS, then an AST may be performed instead of a
QAL2 provided that the SRM measured values obtained in the AST and at least 95 % of the AMS measured
values at standard conditions obtained since the last AST are less than the maximum permissible uncertainty
specified e.g. in the relevant EU Directive.
A set of measurements is valid when all of the requirements below are fulfilled:
— the SRM measurements are performed according to the accepted standard;
— the time period of each AMS measured signal is larger than 90 % of the averaging time (excluding all of
the measured signals which are above 100 % or below 0 % of the measuring range of the AMS, signals
obtained during internal checks (auto calibration), and signals obtained during any other malfunctioning of
the AMS).
During the parallel measurements with the AMS and SRM, each result is considered as a measurement pair
(one AMS measured signal and one SRM measured value) and these shall cover the same time period.
The sampling time for each of the parallel measurements shall be at least 30 min, or at least four times the
response time of the AMS, including the sampling system (as determined during the response time
measurements carried out during QAL1), whichever is the greater. In general the sampling time should equal
the shortest averaging time, which is required by the ELV specification. The recording system shall have an
averaging time significantly shorter than the response time of the AMS.
NOTE 7 If the emissions are at low levels the SRM measured values can be improved for manual SRM by extending
the sampling time.
The time interval between the start of each sample shall be at least 1 h.
The results obtained from the SRM shall be expressed under the same conditions as those measured by the
AMS (e.g. conditions of pressure, temperature, etc.). In order to establish the calibration function and perform
the variability test all additional parameters and values included in the corrections to AMS conditions and
standard conditions shall be obtained for each measurement pair.
EXAMPLE If the AMS measures gaseous HCl in units of mg/m in stack gas containing water vapour, then the SRM
measured values are expressed in the same units (e.g. mg/m in the stack gas with the same water vapour concentration).
In order to fulfil the requirement that the calibration of the AMS is valid over as large a range as possible, and
that it covers most operational situations, parallel measurements over three days are required. However, this
requires several manual SRM measurements of the water vapour concentration. If calibrated AMS measured
values for water vapour are available, these may be used to convert the SRM data to dry or wet basis. When
wet abatement techniques are used, the exhaust gas is saturated and therefore the water vapour
concentration is often nearly constant. In such cases an extended measurement of the water vapour
concentration is of little purpose. In those situations, conversion of SRM data to dry or wet basis may be
carried out using calculated water vapour values.
6.4 Data evaluation
6.4.1 Preparation of data
The steps for providing data required for establishing the calibration function and performing the test of
variability are illustrated in Figure 4.
The figure in the circles indicates the sequence of the steps.
Figure 4 — Flow chart describing the steps in calibration procedure and test for variability
The AMS shall be calibrated at the condition of the flue gas as measured by the AMS. Therefore, the SRM
measured values shall be converted to AMS measuring conditions, if necessary, giving SRM measured
values y to be expressed in concentration units (e.g. mg/m ).
i
The measured signals from the AMS x can be either a signal in an electrical unit (e.g. mA or Volt) or in a
i
concentration unit (e.g. mg/m ).
NOTE For in-situ AMS, that measure the gas directly, the calibration function is reported at the operating conditions.
For extractive AMS measuring at specified conditions, the calibration function is reported at these specified conditions.
The data sets obtained in the parallel measurements shall be checked for possible outliers. The method used
to assess outliers and reasons for excluding outliers shall be given in the QAL2 report. Outliers shall be
reported and identified in the calibration data tables and diagrams.
This standard requires at least 15 valid data points for a QAL2 calibration function. If points are excluded e.g.
through the use of outlier tests, this requirement can be failed. It is therefore recommended that additional
data points be taken, to allow for the exclusion of outliers. If this is not done the QAL2 can be invalid. All data
points shall be used to form the calibration function, unless excluded through the use of outlier tests or have
been shown to be invalid.
6.4.2 Selection of data points from automated SRM
In the case of data sets produced from an automated SRM, which may produce a high number of data points,
any selection of points shall be justified and documented.
6.4.3 Establishing the calibration function
It is presupposed in the standard that the calibration function is linear and has a constant residual standard
deviation. The calibration function shall be described by the model below (see ISO 11095):
y = a+ b x +ε (1)
i i i
where
th
x is the i AMS measured signal; i = 1 to N; N ≥
i
15;
th
y is the i SRM measured value; i = 1 to N; N
i
≥15;
ε is the deviation between y and the expected
i i
value;
a is the intercept of the calibration function;
b
is the slope of th
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