SIST EN 14884:2023
(Main)Stationary source emissions - Determination of total mercury - Automated measuring systems
Stationary source emissions - Determination of total mercury - Automated measuring systems
This European Standard specifies requirements for the calibration and validation (QAL2), the ongoing quality assurance during operation (QAL3) and the annual surveillance test (AST) of automated measuring systems (AMS) used for monitoring total mercury emissions from stationary sources to demonstrate compliance with an emission limit value (ELV). This document is derived from EN 14181 and is only applicable in conjunction with EN 14181.
This document is applicable by direct correlation with the standard reference method (SRM) described in EN 13211.
Emissionen aus stationären Quellen - Bestimmung der Gesamtquecksilber-Konzentration - Automatische Messeinrichtungen
Dieses Dokument legt Anforderungen fest für die Kalibrierung und Validierung (QAL2), die laufende Qualitätssicherung beim Betrieb (QAL3) und die jährliche Funktionsprüfung (AST) von AMS, die zur Überwachung der Gesamtquecksilberemissionen aus stationären Quellen zum Nachweis des Einhaltens von Emissionsgrenzwerten (ELV) verwendet werden. Dieses Dokument ist aus EN 14181 abgeleitet und ist nur in Verbindung mit EN 14181 anwendbar.
Dieses Dokument ist in Verbindung mit dem in EN 13211 beschriebenen Standardreferenzverfahren (SRM) anwendbar.
Émissions de sources fixes - Détermination de la concentration en mercure total - Systèmes de mesurage automatisés
Le présent document définit les exigences relatives à l’étalonnage et à la validation (QAL2), à l’assurance qualité en routine dans les conditions de fonctionnement (QAL3) et au test annuel de surveillance (AST, Annual Surveillance Test) des AMS utilisés pour la surveillance des émissions de mercure total provenant de sources fixes en vue de démontrer la conformité à une valeur limite d’émission (VLE). Le présent document est basé sur l’EN 14181 et est uniquement applicable en association avec l’EN 14181.
Le présent document est applicable en association avec la méthode de référence normalisée (SRM) décrite dans l’EN 13211.
Emisije nepremičnih virov - Določevanje celotnega živega srebra - Avtomatski merilni sistemi
Ta evropski standard določa zahteve za kalibracijo in validacijo (QAL2), stalno zagotavljanje kakovosti med delovanjem (QAL3) in letni nadzorni preskus (AST) avtomatskih merilnih sistemov (AMS), ki se uporabljajo za spremljanje emisij celotnega živega srebra iz nepremičnih virov za dokazovanje skladnosti z mejno vrednostjo emisij (ELV). Dokument izhaja iz standarda EN 14181 in se uporablja samo v povezavi z njim.
Ta dokument se uporablja v neposredni korelaciji s standardno referenčno metodo (SRM), opisano v standardu EN 13211.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 14884:2023
01-marec-2023
Nadomešča:
SIST EN 14884:2006
Emisije nepremičnih virov - Določevanje celotnega živega srebra - Avtomatski
merilni sistemi
Stationary source emissions - Determination of total mercury - Automated measuring
systems
Emissionen aus stationären Quellen - Bestimmung der Gesamtquecksilber-
Konzentration - Automatische Messeinrichtungen
Émissions de sources fixes - Détermination de la concentration en mercure total -
Systèmes de mesurage automatisés
Ta slovenski standard je istoveten z: EN 14884:2022
ICS:
13.040.40 Emisije nepremičnih virov Stationary source emissions
SIST EN 14884:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 14884:2023
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SIST EN 14884:2023
EN 14884
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2022
EUROPÄISCHE NORM
ICS 13.040.40 Supersedes EN 14884:2005
English Version
Stationary source emissions - Determination of total
mercury - Automated measuring systems
Émissions de sources fixes - Détermination de la Emissionen aus stationären Quellen - Bestimmung der
concentration en mercure total - Systèmes de Gesamtquecksilber-Konzentration - Automatische
mesurage automatisés Messeinrichtungen
This European Standard was approved by CEN on 14 November 2022.
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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14884:2022 E
worldwide for CEN national Members.
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SIST EN 14884:2023
EN 14884:2022 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviations . 6
4.1 Symbols . 6
4.2 Abbreviations . 7
5 Principle . 8
6 Calibration and validation of the AMS (QAL2) . 8
6.1 General . 8
6.2 Functional test . 9
6.2.1 General . 9
6.2.2 Zero and span check (EN 14181:2014, A.7) . 9
6.2.3 Linearity test (EN 14181:2014, A.8 and Annex B) . 10
6.2.4 Response time (EN 14181:2014, A.11) . 10
6.2.5 Converter efficiency . 10
6.3 Parallel measurements with the SRM . 10
6.4 Data evaluation . 11
6.4.1 Preparation of data. 11
6.4.2 Selection of data points from automated SRM . 11
6.4.3 Establishing the calibration function . 11
6.5 Calibration function of the AMS and its validity . 11
6.6 Calculation of variability . 11
6.7 Test of variability . 12
6.8 QAL2 report . 12
7 Ongoing quality assurance during operation (QAL3) . 12
8 Annual Surveillance Test (AST) . 12
9 Documentation . 12
Annex A (informative) Example of calculation of the calibration function and of the
variability test . 13
A.1 General . 13
A.2 Data evaluation . 13
A.2.1 General . 13
A.2.2 Calculation of measured values of the SRM at standard conditions . 15
A.2.3 Calibration function . 16
A.2.4 Calibrated values of AMS . 18
A.2.5 Conversion of data to standard conditions . 19
A.2.6 Valid calibration range . 20
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EN 14884:2022 (E)
A.2.7 Test of variability . 21
Annex B (informative) Significant technical changes . 24
Bibliography . 25
3
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SIST EN 14884:2023
EN 14884:2022 (E)
European foreword
This document (EN 14884:2022) 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 June 2023, and conflicting national standards shall be
withdrawn at the latest by June 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 14884:2005.
Annex B provides details of significant technical changes between this document and the previous
edition.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
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SIST EN 14884:2023
EN 14884:2022 (E)
Introduction
This document describes the quality assurance procedures related to automated measuring systems
(AMS) for the determination of total mercury in waste gas, in order to meet the uncertainty requirements
on measured values given by regulations, e.g. EU Directives [1], national or other legislation.
This document is derived from EN 14181, which specifies general procedures for establishing quality
assurance levels (QAL) for AMS installed on industrial plants for the determination of the flue gas
components and other flue gas parameters. It amends EN 14181 and provides guidance specific to total
mercury measurements. It is only applicable in conjunction with EN 14181.
The calibration and validation of mercury AMS that measure the total vapour phase mercury content is
based on parallel measurements with the manual method described in EN 13211. The species of mercury
0 2+
(elemental Hg and oxidized Hg ) and the physical occurrence (gaseous, dust-bound or within droplets)
can vary significantly depending on the type of process to be monitored and this is taken into account
when implementing the SRM.
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EN 14884:2022 (E)
1 Scope
This document specifies requirements for the calibration and validation (QAL2), the ongoing quality
assurance during operation (QAL3) and the annual surveillance test (AST) of AMS used for monitoring
total mercury emissions from stationary sources to demonstrate compliance with an emission limit value
(ELV). This document is derived from EN 14181 and is only applicable in conjunction with EN 14181.
This document is applicable by direct correlation with the standard reference method (SRM) described
in EN 13211.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
EN 13211, Air quality — Stationary source emissions — Manual method of determination of the
concentration of total mercury
EN 14181:2014, Stationary source emissions — Quality assurance of automated measuring systems
EN 17255-1, Stationary source emissions — Data acquisition and handling systems — Part 1: Specification
of requirements for the handling and reporting of data
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 13211 and EN 14181 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at https://www.electropedia.org/
4 Symbols and abbreviations
4.1 Symbols
a intercept of the calibration function
ˆ
best estimate of a
a
b slope of the calibration function
ˆ
best estimate of
b
b
D difference between SRM value, y and calibrated AMS value ŷ
i i i
average of D
D
i
E emission limit value
h water vapour content (by volume)
i counter
N number of paired samples in parallel measurements
k test value for variability
v
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o oxygen content in dry gas (by volume)
o oxygen reference value
s
p gauge pressure
P percentage
standard deviation of the differences D in parallel measurements
s
i
D
t Celsius temperature
t response time
90
total measurement cycle time of AMS with pre-concentration
t
cycle
t sample period of AMS with pre-concentration
sample
U maximum permissible expanded uncertainty
max
th
i AMS measured signal at AMS measuring conditions
x
i
x average of AMS measured signals
th
i SRM measured value
y
i
y average of SRM measured values
th
i SRM measured value at standard conditions
y
i,s
SRM measured value at standard conditions
y
s
lowest SRM measured value at standard conditions
y
s,min
highest SRM measured value at standard conditions
y
s,max
ˆ
y best estimate for the “true value”, calculated from the AMS measured signal x by means
i i
of the calibration function
ˆ
y best estimate for the “true value”, calculated from the AMS measured signal x by means
i,s i
of the calibration function at standard conditions
difference between the maximum and minimum SRM measured value at standard
∆ y
max
conditions
Z
i
check value Grubbs-Test
Z
crit
critical limit – Grubbs-Test
σ standard deviation associated with the uncertainty derived from requirements of
0
legislation
4.2 Abbreviations
AMS automated measuring system
AST annual surveillance test
DAHS data acquisition and handling system
ELV emission limit value
QAL quality assurance level
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EN 14884:2022 (E)
QAL1 first quality assurance level
QAL2 second quality assurance level
QAL3 third quality assurance level
SRM standard reference method
5 Principle
The AMS measures total gaseous mercury, both elemental and oxidized, requiring a converter to reduce
oxidized Hg into elemental Hg prior to measurement of total Hg. Mercury compounds are reactive and
can be adsorbed onto particulate deposits within the sampling system. Therefore, the sample is often
diluted with nitrogen or air in order to aid sample transport and reduce cross-interferences from other
gas components within the flue gas matrix. The Hg AMS are capable of measuring the total concentration
3
in μg/m and reporting the undiluted vapour phase Hg, regardless of speciation. The
sampling system is heated in order to minimize mercury chloride adsorption.
NOTE AMS often report Hg concentration on a wet basis, i.e. the water vapour from the process sample is
retained within the sample. The water content is then required in order to correct the Hg concentration to dry
reference conditions. If the water content is not measured by any of the installed AMS, the use of a calculated water
content is acceptable as described in CEN/TS 17286 [2].
The general principles of quality assurance of AMS are laid down in EN 14181. These are applied within
this standard with the amendments specific to mercury AMS being specified in the subsequent Clauses.
In this context, an AMS is any system that continuously samples the mercury content of flue gas. This may
be a system that continuously analyses for mercury, typically producing a one-minute average
concentration that is based on discrete or time-integrated data sampling. Alternatively, this may be a
system that pre-concentrates the mercury in the flue gas, prior to analysis, within a gold accumulator for
example, with a measurement cycle of typically 2 to 10 min duration. Dual accumulators are then typically
used to provide continuous sampling and analysis.
Long-term sampling systems involve continuous, repetitive flue gas sampling using paired sorbent traps,
located within the flue gas duct, for mercury capture, with subsequent trap analysis of the time-integrated
samples. Long term sampling is typically from one day to two weeks sampling duration. The type testing,
functional tests and general quality assurance requirements, applicable to long-term sampling systems,
are specified in CEN/TS 17286 [2]. However, these systems also require QAL2 calibration according to
EN 14181 and this standard, except for the functional tests (EN 14181:2014, 6.2 and 8.2). Alternative
functional tests and quality assurance procedures are specified in CEN/TS 17286 [2].
6 Calibration and validation of the AMS (QAL2)
6.1 General
The AMS shall be calibrated and validated in accordance with EN 14181 with the modifications specified
in 6.2 to 6.8 of this standard. Unless otherwise specified by regulation, the maximum permissible
uncertainty is specified as 40 % of the daily ELV. EN 14181 specifies that the daily ELV, is used for quality
assurance purposes.
However, for mercury a lower long term ELV, e.g. an annual ELV, may be specified. If this long term ELV
is less than 50 % of the daily ELV, then the long-term ELV shall be used instead of the daily ELV, for all
quality assurance assessments. However, a multiple of the longer term ELV may be used for quality
assurance purposes if this is agreed with the competent authority, for example, if this is required due to
more variable mercury emissions during QAL2 testing.
NOTE Annex A shows an example of the application of QAL2 for an AMS.
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6.2 Functional test
6.2.1 General
Functional tests are performed to ensure that the AMS is working according to the specifications and to
check the active measurement components of the AMS to ensure that they are not unduly influenced by
contamination. The functional tests shall be carried out in accordance with EN 14181:2014, Annex A,
with the modifications specified below. Both elemental and oxidized reference materials may be used for
the functional tests, noting that only oxidized reference material (e.g. HgCl ) is used for the converter
2
efficiency test. The manufacturers’ operating instructions for the reference material generators shall be
followed, ensuring that a sufficient flow of reference material is used to avoid simultaneous entrainment
of flue gas into the probe. The uncertainty of the reference materials shall be assessed and reported by
the test laboratory. The functional test shall be performed by an experienced testing laboratory, which
has been recognized by the competent authority. The independent reference material generators shall be
traceable to national standards.
NOTE Protocols for the certification of both elemental and oxidized mercury generators are under
development within the ‘European Metrology Programme for Innovation and Research (EMPIR) project 19NRM03
SI-Hg’. This project is also assessing the stability of mercury containing solutions that are used within the
generators. Until further guidance can be provided, these aspects continue to be addressed by the quality assurance
procedures of the accredited test laboratory. Analytical traceability is normally established using certified reference
materials such as NIST 3133 and NIST 3177.
All functional tests shall be performed by passing gaseous reference material through the entire AMS,
including the filter, dilution system (if applicable), sample line, and the oxidized mercury conversion
system. In the case of older AMS, when it is not possible to introduce reference material upstream of the
sample filter, then elements of the sampling system may need to be bypassed in which case the test
laboratory shall report a non-conformance with this document.
In the case of oxidized mercury, a reference material containing water vapour is typically specified in
order to minimize mercury losses and hold-up within the sampling system. Care should be taken to
volume correct the reference mercury concentration to take account of the injected water vapour
concentration which should ideally be held constant. If mercury chloride solutions are used within an
oxidized mercury generator supplied by the test laboratory then the stability of those solutions should
be checked by the test laboratory.
6.2.2 Zero and span check (EN 14181:2014, A.7)
Elemental mercury shall be used for the independent span check provided that the reference material
generator used by the test laboratory is calibrated with metrological traceability to the SI units.
NOTE Calibration according to EN ISO 17025 [3] demonstrates traceability to SI units.
Zero and span checks shall be performed by passing gaseous reference material through the entire AMS.
The selected span concentration shall be no higher than 200 % of the daily ELV. The difference between
the measured span result and the span gas concentration shall be ≤ 5,0 % of the daily ELV. If the first span
check is outside of this tolerance then the AMS shall be adjusted according to the span adjustment
procedure and re-tested. The results of these adjustments shall be reported by the test laboratory.
If the zero point is used to establish the calibration function according to EN 14181:2014, 6.4.3,
procedure b), or procedure c), the zero test shall be used to prove that the AMS gives a reading at or below
detection limit (as demonstrated in QAL1) at a zero concentration. The test results shall be presented in
the QAL2 calibration report.
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EN 14884:2022 (E)
If the span point is used to establish the calibration function according to EN 14181:2014, 6.4.3,
procedure c), the test laboratory may select the most appropriate reference material to be used for
extension of the QAL2 calibration, taking into account the characteristics of the flue gas emissions, e.g.
0
flue gas downstream of a wet absorption unit is expected to contain predominantly Hg . The span
reference material expanded uncertainty shall be within ± 5 % of the reference concentration,
3
or ± 0,25 μg/m , whichever is higher. The test results shall be presented in the QAL2 calibration report.
In this case, the span gas concentration shall also be measured by the SRM, i.e. by passing the independent
mercury generator output through the SRM sampling train. This is achieved by splitting the mercury
generator output between the AMS and the SRM to obtain simultaneous measurements but, if that is not
possible due to insufficient generator flow rate, then the generator output may be switched from the AMS
to the SRM to obtain consecutive measurements.
6.2.3 Linearity test (EN 14181:2014, A.8 and Annex B)
Linearity tests shall be performed by passing gaseous reference materials through the entire AMS.
EN 14181 requires that the concentration range specified for the linearity test shall extend to at least the
daily ELV. However, the measuring range of the instrument shall also capture the peak concentrations
emitted by the process and so the highest concentration specified for the linearity test may be much
higher than the daily ELV.
If the anticipated peak process concentrations are higher than the daily ELV, then additional
concentration levels may be specified provided that these additional concentration levels pass the
residual test based on the daily ELV.
6.2.4 Response time (EN 14181:2014, A.11)
Response time tests shall be performed by passing reference material through the entire AMS.
The response time pass criterion is 400 s
6.2.5 Converter efficiency
The AMS convertor efficiency shall be tested to confirm that oxidized Hg is converted to elemental Hg.
Oxidized reference material (e.g. HgCl ) shall be introduced into the probe, upstream of the filter, to test
2
for losses of Hg across the sampling arrangement. The converter efficiency is defined as the measured Hg
concentration divided by the expected reference Hg concentration multiplied by 100 %. The conversion
efficiency shall be ≥ 90 %. Special care should be taken, when handling oxidized Hg reference gases, as
surface reactions in the sample tubing can result in longer response times compared to elemental Hg
reference gases.
6.3 Parallel measurements with the SRM
According to EN 14181, QAL 2 at least 15 parallel measurements shall be performed with the AMS and
SRM in order to calibrate and validate the AMS by use of an independent method. The measurements
shall be performed at normal operating conditions of the plant as required by EN 14181.
For AMS with pre-concentration of Hg, the SRM measurement shall start at the beginning of a new AMS
total measurement cycle and shall be performed for a complete number of measurement cycles, in
addition to complying with the sample time requirements specified by EN 14181.
The SRM shall be applied in accordance with EN 13211. Alternative methods that are demonstrated to be
equivalent to the SRM, according to EN 14793, may be approved by the competent authority and these
shall be applied in accordance with the relevant European or ISO standards.
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EN 14884:2022 (E)
Reducing the number of measurements and increasing the individual SRM sampling time can lead to a
better quantification of very low mercury concentrations. If most of the SRM measured results are
expected to be below the maximum permissible uncertainty, the sampling duration shall be extended to
a maximum of 2 h per test. The number of parallel measurements may then be reduced to a minimum of
5 valid measurements over 3 days. The total SRM sampling time shall be at least 7,5 h, which is equal to
15 times 30 min (the minimum requirement). The sampling duration shall be the same for all parallel
measurements. However, if more than 2 of the AMS measured values are above the maximum permissible
uncertainty then a full QAL2 is required.
If all of the SRM measured results are below the maximum permissible uncertainty, EN 14181, procedure
c) may be used to improve the quality of the calibration using reference materials, if y is less than
s, min
30 % of the ELV. In this situation, the reference material shall meet the requirements given in 6.2.2 of this
standard.
6.4 Data evaluation
6.4.1 Preparation of data
6.4.1.1 Automatic recording of AMS output signals
The AMS output signal to be recorded directly by the test laboratory, may be analogue and/or digital. The
AMS shall be configured to have an output range which is large enough to gather readings with sufficient
resolution across the range. In the case of an analogue output, the instantaneous AMS output signal shall
be automatically recorded during the parallel measurements in order to be electronically averaged.
Alternatively, if the plant Data Acquisition and Handling System (DAHS) is used to obtain the measured
raw data then this shall conform to the requirements of EN 17255-1.
The AMS self-checks shall be prevented during SRM sampling.
6.4.1.2 Data sampling
Sampling intervals of data provided by an analogue or digital output shall not exceed 10 s. Data sampling
intervals and averaging times shall be reported in the calibration report.
NOTE If the plant DAHS is used to obtain the measured raw data, only one-minute averages of the sampled data
migh
...
SLOVENSKI STANDARD
oSIST prEN 14884:2021
01-junij-2021
Kakovost zraka - Emisije nepremičnih virov - Določevanje celotnega živega srebra:
avtomatski merilni sistemi
Air quality - Stationary source emissions - Determination of total mercury: automated
measuring systems
Luftbeschaffenheit - Emissionen aus stationären Quellen - Bestimmung der
Gesamtquecksilber-Konzentration: Automatische Messeinrichtungen
Qualité de l'air - Emissions de sources fixes - Détermination de la concentration en
mercure total : systèmes automatiques de mesure
Ta slovenski standard je istoveten z: prEN 14884
ICS:
13.040.40 Emisije nepremičnih virov Stationary source emissions
oSIST prEN 14884:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 14884:2021
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oSIST prEN 14884:2021
DRAFT
EUROPEAN STANDARD
prEN 14884
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2021
ICS 13.040.40 Will supersede EN 14884:2005
English Version
Air quality - Stationary source emissions - Determination
of total mercury: automated measuring systems
Qualité de l'air - Emissions de sources fixes - Luftbeschaffenheit - Emissionen aus stationären
Détermination de la concentration en mercure total : Quellen - Bestimmung der Gesamtquecksilber-
systèmes automatiques de mesure Konzentration: Automatische Messeinrichtungen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 264.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14884:2021 E
worldwide for CEN national Members.
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oSIST prEN 14884:2021
prEN 14884:2021 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols and abbreviations . 5
4.1 Symbols . 5
4.2 Abbreviations . 6
5 Principle . 7
6 Calibration and validation of the AMS (QAL2) . 7
6.1 General . 7
6.2 Functional test . 8
6.3 Parallel measurements with the SRM . 9
6.4 Data evaluation . 10
6.5 Calibration function of the AMS and its validity . 10
6.6 Calculation of variability . 10
6.7 Test of variability . 10
6.8 QAL2 report . 10
7 Ongoing quality assurance during operation (QAL3) . 11
8 Annual Surveillance Test (AST) . 11
9 Documentation . 11
Annex A (informative) Example of calculation of the calibration function and of the
variability test . 12
A.1 General . 12
A.2 Data evaluation . 12
Annex B (normative) Quality Assurance Level 1 . 23
B.1 General . 23
B.2 Zero and span checks . 23
B.3 Converter efficiency check . 23
B.4 QAL3 tests . 23
B.5 Mercury AMS with pre-concentration . 23
Annex C (informative) Significant technical changes . 24
Bibliography . 25
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European foreword
This document (prEN 14884:2021) has been prepared by Technical Committee CEN/TC 264 “Air
Quality”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 14884:2005.
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Introduction
This document describes the quality assurance procedures related to automated measuring systems
(AMS) for the determination of total mercury in waste gas, in order to meet the uncertainty requirements
on measured values given by regulations, e.g. EU Directives [1], national or other legislation.
This document is derived from EN 14181, which specifies general 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. It amends EN 14181 and
provides guidance specific to total mercury measurements. It is only applicable in conjunction with
EN 14181.
The calibration and validation of mercury AMS that measure the total vapour phase mercury content is
based on parallel measurements with the manual method described in EN 13211. The species of mercury
0 2+
(elemental Hg and oxidized Hg ) and the physical occurrence (gaseous, dust-bound or within droplets)
can vary significantly depending on the type of process to be monitored and this is taken into account
when implementing the SRM.
Annex C provides details of significant technical changes between this European Standard and the
previous edition.
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1 Scope
This document specifies requirements for the calibration and validation (QAL2), the ongoing quality
assurance during operation (QAL3) and the annual surveillance test (AST) of automated measuring
systems (AMS) used for monitoring total mercury emissions from stationary sources to demonstrate
compliance with an emission limit value (ELV). This document is derived from EN 14181 and is only
applicable in conjunction with EN 14181. This standard also specifies type testing (QAL1) requirements
in Annex B that will be incorporated into EN 15267-3 when that standard is next revised.
This document is applicable by direct correlation with the standard reference method (SRM) described
in EN 13211.
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 13211, Air quality - Stationary source emissions - Manual method of determination of the concentration
of total mercury
EN 14181:2014, Stationary source emissions - Quality assurance of automated measuring systems
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 17255-1, Stationary source emissions - Data acquisition and handling systems - Part 1: Specification of
requirements for the handling and reporting of data
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 13211 and EN 14181 apply.
4 Symbols and abbreviations
4.1 Symbols
a intercept of the calibration function
ˆ
best estimate of a
a
b slope of the calibration function
ˆ
best estimate of b
b
D difference between SRM value, y and calibrated AMS value ŷ
i i i
average of D
D i
E emission limit value
h absolute water vapour content (by volume)
i counter
N number of paired samples in parallel measurements
k test value for variability
v
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o oxygen content in dry gas (by volume)
p gauge pressure
standard deviation of the differences D in parallel measurements
i
s
D
t Celsius temperature
t response time
90
t total measurement cycle time of AMS with pre-concentration
cycle
t sample period of AMS with pre-concentration
sample
U maximum permissible expanded uncertainty
max
th
i AMS measured signal at AMS measuring conditions
x
i
x average of AMS measured signals
th
i SRM measured value
y
i
y average of SRM measured values
th
i SRM measured value at standard conditions
y
i,s
SRM measured value at standard conditions
y
s
lowest SRM measured value at standard conditions
y
s,min
highest SRM measured value at standard conditions
y
s,max
ˆ
y best estimate for the ”true value”, calculated from the AMS measured signal x by means of the
i i
calibration function
ˆ
y best estimate for the ”true value”, calculated from the AMS measured signal x by means of the
i,s i
calibration function at standard conditions
difference between the maximum and minimum SRM measured value at standard conditions
∆ y
max
σ standard deviation associated with the uncertainty derived from requirements of legislation
0
4.2 Abbreviations
AMS automated measuring system
AST annual surveillance test
DAHS data acquisition and handling system
ELV emission limit value
QAL quality assurance level
QAL1 first quality assurance level
QAL2 second quality assurance level
QAL3 third quality assurance level
SRM standard reference method
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5 Principle
The AMS measures total gaseous mercury, both elemental and oxidized, requiring a converter to reduce
oxidized Hg into elemental Hg prior to measurement of total Hg. Mercury compounds are reactive and
can be adsorbed onto particulate deposits within the sampling system. Therefore, the sample is often
diluted with nitrogen or air in order to aid sample transport and reduce cross-interferences from other
gas components within the flue gas matrix. The Hg AMS must be capable of measuring the total
3
concentration in μg/m and reporting the undiluted vapour phase Hg, regardless of speciation.
NOTE AMS often report Hg concentration on a wet basis, i.e. the water vapour from the process sample is
retained within the sample. The water content is then required in order to correct the Hg concentration to dry
reference conditions. If the water content is not measured by any of the installed AMS, the use of a calculated water
content may be acceptable as described in CEN/TS 17286 [2].
The general principles of quality assurance of AMS are laid down in EN 14181. These are applied within
this standard with the amendments specific to mercury AMS being specified in the following sections.
In this context, an AMS is any system that continuously samples the mercury content of flue gas. This may
be a system that continuously analyses for mercury, typically producing a one-minute average
concentration that is based on discrete or time-integrated data sampling. Alternatively, this may be a
system that pre-concentrates the mercury in the flue gas, prior to analysis, within a gold accumulator for
example, with a measurement cycle of typically 2 to 10 min duration. Dual accumulators are then typically
used to provide continuous sampling and analysis. Mercury specific requirements relating to QAL1 type
testing are specified in Annex B noting that these provisions will be incorporated into EN 15267-3 when
that standard is next revised.
Long-term sampling systems involve continuous, repetitive flue gas sampling using paired sorbent traps,
located within the flue gas duct, for mercury capture, with subsequent trap analysis of the time-integrated
samples. Long term sampling is typically from one day to two weeks sampling duration. The type testing,
functional tests and general quality assurance requirements, applicable to long-term sampling systems,
are specified in CEN/TS 17286 [2]. However, these systems also require QAL2 calibration according to
EN 14181 and this standard, except for the functional tests (6.2 and 8.2 of EN 14181:2014). Alternative
functional tests and quality assurance procedures are defined in CEN TS 17286 [2].
6 Calibration and validation of the AMS (QAL2)
6.1 General
The AMS shall be calibrated and validated in accordance with EN 14181 with the modifications specified
in 6.2 to 6.8 of this standard. Unless otherwise specified by regulation, the maximum permissible
uncertainty is defined as 40 % of the daily ELV. EN 14181 specifies that the short term ELV, i.e. the daily
ELV is used for quality assurance purposes.
However, for mercury a lower long term ELV, e.g. an annual ELV, may be specified. If the long term ELV
is less than 50 % of the short term ELV, then the long-term ELV shall be used instead of the daily ELV, for
all quality assurance assessments.
NOTE A multiple of the long term ELV may be used for quality assurance purposes if this is agreed with the
competent authority, for example, if this is required due to more variable mercury emissions during QAL2 testing.
NOTE Annex A shows an example of the application of QAL2 for an AMS.
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6.2 Functional test
6.2.1 General
Functional tests are performed to ensure that the AMS is working according to the specifications and to
check the active measurement components of the AMS to ensure that they are not unduly influenced by
contamination. The functional tests shall be carried out in accordance with EN 14181:2014 Annex A with
the modifications specified below. Both elemental and oxidized reference materials may be used for the
functional tests, noting that only oxidized reference material (e.g. HgCl ) is used for the converter
2
efficiency test. The manufacturers’ operating instructions for the reference material generators shall be
followed, ensuring that a sufficient flow of reference material is used to avoid simultaneous entrainment
of flue gas into the probe. The uncertainty of the reference materials shall be assessed and reported by
the test laboratory. The functional test shall be performed by an experienced testing laboratory, which
has been recognized by the competent authority.The independent reference material generators shall be
traceable to national standards.
All functional tests shall be performed by passing gaseous reference material through the entire AMS,
including the filter, dilution system (if applicable), sample line, and the oxidized mercury conversion
system. In the case of older AMS, when it is not possible to introduce reference material upstream of the
sample filter, then elements of the sampling system may need to be bypassed in which case the test
laboratory shall report a non-conformance with this standard.
In the case of oxidized mercury, a reference material containing water vapour is typically specified in
order to minimize mercury losses and hold-up within the sampling system. Care should be taken to
volume correct the reference mercury concentration to take account of the injected water vapour
concentration which should ideally be held constant. If mercury chloride solutions are used within an
oxidized mercury generator supplied by the test laboratory then the stability of those solutions should
be checked by the test laboratory.
6.2.2 Zero and span check (EN 14181 Annex A.7)
Zero and span checks shall be performed by passing gaseous reference material through the entire AMS.
The selected span concentration shall be no higher than 200 % of the daily ELV. The agreement between
the measured span result and the span gas concentration shall be better than 5,0 % of the daily ELV. If
the first span check is outside of this tolerance then the AMS shall be adjusted according to the QAL1 span
adjustment procedure and re-tested. The results of these adjustments shall be reported by the test
laboratory.
If the zero point is used to establish the calibration function according to EN 14181:2014, 6.4.3 procedure
b), or procedure c), the zero test shall be used to prove that the AMS gives a reading at or below detection
limit (as demonstrated in QAL1) at a zero concentration. The test results shall be presented in the QAL2
calibration report.
If the span point is used to establish the calibration function according to EN 14181:2014, 6.4.3 procedure
c), the span reference material expanded uncertainty shall be within ± 5 % of the reference
3
concentration, or ± 0,25 ug/m , whichever is higher. The test results shall be presented in the QAL2
calibration report. In this case, the span gas concentration shall also be measured by the SRM, i.e. by
passing the independent mercury generator output through the SRM sampling train. This is achieved by
splitting the mercury generator output between the AMS and the SRM to obtain simultaneous
measurements but, if that is not possible due to insufficient generator flow rate, then the generator output
may be switched from the AMS to the SRM to obtain consecutive measurements.
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6.2.3 Linearity test (EN 14181 Annex A.8 and Annex B)
Linearity tests shall be performed by passing gaseous reference materials through the entire AMS.
EN 14181 requires that the concentration range specified for the linearity test shall extend to at least the
daily ELV. However, the measuring range of the instrument shall also capture the peak concentrations
emitted by the process and so the highest concentration specified for the linearity test may be much
higher than the short term ELV.
If the anticipated peak process concentrations are higher than the daily ELV, then additional
concentration levels may be specified provided that these additional concentration levels pass the
residual test based on the daily ELV.
6.2.4 Response time (EN 14181 Annex A.11)
Response time tests shall be performed by passing reference material through the entire AMS.
The response time pass criterion for AMS with pre-concentration is increased by the cycle time of the
AMS. For example, if the response time criterion for AMS without pre-concentration is 400 s and the cycle
time of the AMS with pre-concentration is 620 s, then the response time criterion becomes 1020 s
(17 min).
6.2.5 Cycle time for AMS with pre-concentration
AMS with mercury pre-concentration are characterized by a total measurement cycle time, t , and a
cycle
sample period, t . The ratio t / t shall be larger than 90 %. However, a ratio t / t less
sample sample cycle sample cycle
than 90 % may be used, if there are no rapid changes in the mass concentration of mercury, subject to
approval by the competent authority.
The maximum length of the measurement cycle shall not be longer than the shortest ELV averaging
period, e.g. 30 min, for these AMS.
6.2.6 Converter efficiency
The AMS convertor efficiency shall be tested to confirm that oxidized Hg is converted to elemental Hg.
2
Oxidized reference material (e.g. HgCl ) shall be introduced into the probe, upstream of the filter, to test
for losses of Hg across the sampling arrangement. The converter efficiency is defined as the measured Hg
concentration divided by the expected reference Hg concentration multiplied by 100 %. The conversion
efficiency shall be ≥ 90 %. Special care should be taken, when handling oxidized Hg reference gases, as
surface reactions in the sample tubing can result in longer response times compared to elemental Hg
reference gases.
6.3 Parallel measurements with the SRM
According to EN 14181, QAL 2 at least 15 parallel measurements shall be performed with the AMS and
SRM in order to calibrate and validate the AMS by use of an independent method. The measurements
shall be performed at normal operating conditions of the plant as required by EN 14181.
For AMS with pre-concentration of Hg, the SRM measurement shall start at the beginning of a new AMS
total measurement cycle and shall be performed for a complete number of measurement cycles, in
addition to complying with the sample time requirements defined by EN 14181.
The SRM shall be applied in accordance with EN 13211. Alternative methods that are demonstrated to be
equivalent to the SRM, according to EN 14793, may be approved by the competent authority and these
shall be applied in accordance with the relevant European or ISO standards.
Reducing the number of measurements and increasing the individual SRM sampling time can lead to a
better quantification of very low mercury concentrations. If most of the SRM measured results are
expected to be below the maximum permissible uncertainty, the sampling duration shall be extended to
a maximum of 2 h per test. The number of parallel measurements may then be reduced to a minimum of
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5 valid measurements over 3 days. The total SRM sampling time shall be at least 7,5 h, which is equal to
15 times 30 min (the minimum requirement). The sampling duration shall be the same for all parallel
measurements. However, if more than 2 of the AMS measured values are above the maximum permissible
uncertainty then a full QAL2 is required.
If all of the SRM measured results are below the maximum permissible uncertainty, EN 14181 procedure
c) may be used to improve the quality of the calibration using reference materials, if y is less than
s, min
30 % of the ELV. In this situation, the uncertainty of the reference material must meet the requirements
given in section 6.2.1 of this standard.
6.4 Data evaluation
6.4.1 Preparation of data
6.4.1.1 Automatic recording of AMS output signals
The AMS output signal to be recorded directly by the test laboratory, may be analogue and/or digital. The
AMS shall be configured to have an output range which is large enough to gather readings with sufficient
resolution across the range. In the case of an analogue output, the instantaneous AMS output signal shall
be automatically recorded during the parallel measurements in order to be electronically averaged.
Alternatively, if the plant Data Acquisition and Handling System (DAHS) is used to obtain the measured
raw data then this shall conform to the requirements of EN 17255-1.
The AMS self-checks shall be prevented during SRM sampling.
6.4.1.2 Data sampling
Sampling intervals of data provided by an analogue or digital output shall not exceed 10 s. Data sampling
intervals and averaging times shall be reported in the calibration report.
NOTE If the plant DAHS is used to obtain the measured raw data, only one-minute averages of the sampled
data can be available for analysis.
6.4.2 Selection of data points from automated SRM
Since the mercury SRM is a manual method, 6.4.2 of EN 14181:2014 does not apply.
6.4.3 Establishing the calibration function
No additional requirements to section 6.4.3 of EN 14181:2014.
6.5 Calibration function of the AMS and its validity
No additional requirements to section 6.5 of EN 14181:2014.
6.6 Calculation of variability
No additional requirements to section 6.6 of EN 14181:2014.
6.7 Test of variability
3
When the mean SRM mercury concentration is < 2,5 ug/m , the pass criterion defined in section 6.7 of
3
EN 14181 may be modified as follows. The variability is accepted if s ≤ 0,5 ug/m .
D
6.8 QAL2 report
Any deviation from the procedures specified in EN 14181 and in this European Standard and their
possible influence on the results obtained shall be presented in the QAL2 report.
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7 Ongoing quality assurance during operation (QAL3)
The QAL3 shall be performed according to EN 14181. When the QAL3 is performed with mercury
reference material generators that are not integrated within the AMS, particular care is required to
ensure that the generator set-point and performance is consistent with past behaviour, in order to avoid
an apparent AMS drift that is actually related to the instability of the reference material.
AMS internal elemental or oxidized mercury generators can be used to perform the QAL3 provided that
they are type tested according to EN 15267-3 as QAL3 compliant.
8 Annual Surveillance Test (AST)
The AST shall be performed according to EN 14181. The first part of the AST is the functional tests, which
shall be performed according to Annex A of EN 14181:2014 with the modifications and additions
specified in 6.2 of this standard, including the converter efficiency test.
3
When the mean SRM mercury concentration is < 2,5 ug/m , the pass criteria defined in section 8.6 of
3
EN 14181 may be modified as follows. The variability is accepted if s ≤ 0,5 ug/m . The validity is
D
3
accepted if |D| ≤ 0,5 ug/m .
9 Documentation
The AMS documentation shall meet the requirements of EN 14181.
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