oSIST prEN 14884:2021

SLOVENSKI STANDARD
oSIST prEN 14884:2021
01-junij-2021

Kakovost zraka - Emisije nepremičnih virov - Določevanje celotnega živega srebra:

Air quality - Stationary source emissions - Determination of total mercury: automated

Qualité de l'air - Emissions de sources fixes - Détermination de la concentration en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Qualité de l'air - Emissions de sources fixes - Luftbeschaffenheit - Emissionen aus stationären

Détermination de la concentration en mercure total : Quellen - Bestimmung der Gesamtquecksilber-

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

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

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

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14884:2021 E

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

This document (prEN 14884:2021) has been prepared by Technical Committee CEN/TC 264 “Air

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

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

(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

Annex C provides details of significant technical changes between this European Standard and the

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

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

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

For the purposes of this document, the terms and definitions given in EN 13211 and EN 14181 apply.

y best estimate for the ”true value”, calculated from the AMS measured signal x by means of the

y best estimate for the ”true value”, calculated from the AMS measured signal x by means of the

difference between the maximum and minimum SRM measured value at standard conditions

σ standard deviation associated with the uncertainty derived from requirements of legislation

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

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

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

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].

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

AMS with mercury pre-concentration are characterized by a total measurement cycle time, t , and a

sample period, t . The ratio t / t shall be larger than 90 %. However, a ratio t / t less

than 90 % may be used, if there are no rapid changes in the mass concentration of mercury, subject to

The maximum length of the measurement cycle shall not be longer than the shortest ELV averaging

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

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

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

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

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

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

30 % of the ELV. In this situation, the uncertainty of the reference material must meet the requirements

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

Sampling intervals of data provided by an analogue or digital output shall not exceed 10 s. Data sampling

NOTE If the plant DAHS is used to obtain the measured raw data, only one-minute averages of the sampled

When the mean SRM mercury concentration is < 2,5 ug/m , the pass criterion defined in section 6.7 of

EN 14181 may be modified as follows. The variability is accepted if s ≤ 0,5 ug/m .

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.

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

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

When the mean SRM mercury concentration is < 2,5 ug/m , the pass criteria defined in section 8.6 of

EN 14181 may be modified as follows. The variability is accepted if s ≤ 0,5 ug/m . The validity is