SIST EN 14790:2005

SLOVENSKI STANDARD
SIST EN 14790:2005
01-december-2005
(PLVLMHQHSUHPLþQLKYLURY'RORþHYDQMHYRGQHSDUHYRGYRGQLNLK
Stationary source emissions - Determination of the water vapour in ducts
Emissionen aus stationären Quellen - Bestimmung von Wasserdampf in Leitungen
Emissions de sources fixes - Détermination de la vapeur d'eau dans les conduits
Ta slovenski standard je istoveten z: EN 14790:2005
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
SIST EN 14790:2005 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 14790:2005

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SIST EN 14790:2005
EUROPEAN STANDARD
EN 14790
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2005
ICS 11.040.40

English Version
Stationary source emissions - Determination of the water vapour
in ducts
Emissions de sources fixes - Détermination de la vapeur Emissionen aus stationären Quellen - Bestimmung von
d'eau dans les conduits Wasserdampf in Leitungen
This European Standard was approved by CEN on 30 September 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14790:2005: E
worldwide for CEN national Members.

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SIST EN 14790:2005
EN 14790:2005 (E)
Contents Page
Foreword .4
1 Scope.5
2 Normative references.5
3 Terms and definitions.6
4 Principle.9
4.1 General.9
4.2 Adsorption or condensation/adsorption method .9
4.3 Temperature method.9
5 Apparatus.10
5.1 General.10
5.2 Sampling probe.10
5.3 Filter housing.10
5.4 Particle filter.11
5.5 Trapping unit.11
5.6 Cooling System (optional).11
5.7 Sampling pump.11
5.8 Gas volume meter.11
5.9 Barometer.12
5.10 Balance.12
5.11 Temperature measurement.12
6 Measurement procedure.12
6.1 General requirements.12
6.2 Preparation and installation of equipment.12
6.2.1 Sampling location.12
6.2.2 Sampling point.13
6.2.3 Assembling the equipment .13
6.3 Leak test.13

6.4 Performing of the sampling.14
6.4.1 Introduction of the probe in the duct.14
6.4.2 Sampling.14
6.5 Repeatability of the weighing.14
6.6 Procedure for gas streams saturated with water (droplets present) .15
7 Determination of the characteristics of the method: sampling and analysis.15
7.1 Introduction.15
7.2 Relevant performance characteristics of the method and performance criteria .15
7.3 Establishment of the uncertainty budget.16
7.4 Equivalency with an alternative method .17
8 Evaluation of the method in the field.17
9 Water vapour determination.18
10 Report.20
Annex A (normative) Determination of water vapour concentration for water saturated gas, at P
std
= 101,325 kPa.21
Annex B (informative) Type of sampling equipments .25
Annex C (informative) Example of assessment of compliance of reference method for water
vapour with requirements on emission measurements.26
C.1 General.26
C.2 Process of uncertainty estimation.26
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SIST EN 14790:2005
EN 14790:2005 (E)

C.2.1 Determination of the model equation.26
C.2.2 Quantification of uncertainty components .26
C.2.3 Calculation of the combined uncertainty.26
C.3 Specific conditions in the field .27
C.4 Performance characteristics of the method .28
C.5 Calculation of standard uncertainty of the concentration .28
C.5.1 Model equation and application of the rule of the uncertainty propagation .29
C.5.2 Results of standard uncertainties calculations.33
C.5.3 Estimation of the combined uncertainty.36

Annex D (informative) Evaluation of the method in the field .37
D.1 General.37
D.2 Characteristics of installations.37
D.3 Repeatability and reproducibility in the field.38
D.3.1 Repeatability.39
D.3.2 Reproducibility.40
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive.41
Bibliography.42

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SIST EN 14790:2005
EN 14790:2005 (E)
Foreword
This European Standard (EN 14790:2005) has been prepared by Technical Committee CEN/TC 264 “Air
qualilty”, 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 2006, and conflicting national standards shall be withdrawn at the
latest by May 2006.
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association, and supports essential requirements of EU Directive(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this European
Standard.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
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SIST EN 14790:2005
EN 14790:2005 (E)
1 Scope
This European Standard describes the condensation/adsorption technique, including the sampling system, to
determine the water vapour concentration in the flue gases emitting to atmosphere from ducts and stacks.
This technique is usually used all over Europe for water vapour monitoring. However to be implemented as
the Standard Reference Method (SRM), the user has to demonstrate that the performance characteristics of
the method are better than the performance criteria defined in this European Standard and that the overall
uncertainty of the method is less than ± 20 % of the measured value. This European Standard as the
Standard Reference Method (SRM) is used for periodic monitoring and for calibration or control of Automatic
Measuring Systems (AMS) permanently installed on a stack, for regulatory purposes or other purposes.
An Alternative Method to this SRM may be used provided that the user can demonstrate equivalence
according to the Technical Specification CEN/TS 14793, to the satisfaction of his national accreditation body
or law.
The determination of water vapour is mainly necessary for:
 regulatory purposes, to express the concentration at standard conditions (on dry gas);
 adjust the flow rate for isokinetic sampling, when a dry gas flow rate metering device is used.
For both applications, the quantity to be measured is the amount of water present in the gas phase (vapour),
which does not include water droplets.
This European Standard is applicable in the range from 4 % to 40 % relative humidity and for water vapour
3 3
concentration from 29 g/m to 250 g/m as a wet gas, although for a given temperature the upper limit of the
method is related to the maximum pressure of water in air or in the gas.
This European Standard has been evaluated during field tests on waste incineration, co-incineration and large
combustion installations. It has been validated for sampling periods of 30 min in the concentration range of
7 % to 26 % volume.
In this European Standard all the concentrations are expressed in normal conditions (273 K and 101,3 kPa).
NOTE For saturated conditions the condensation/adsorption method is not applicable. Some guidance is given in this
European Standard to deal with flue gas when droplets are present.
2 Normative references
The following referenced documents are indispensable for the application of this European Standard. For
dated references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ENV 13005, Guide to the expression of uncertainly in measurement.
CEN/TS 14793, Stationary source emission - Intralaboratory validation procedure for an alternative method
compared to a reference method.
EN ISO 14956, Air Quality – Evaluation of the suitability of a measurement procedure by comparison with a
required measurement uncertainty (ISO 14956:2002).
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3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
absorber
device in which water vapour is absorbed
3.2
detection limit (L )
D
concentration value of the measurand below which there is at least 95 % level of confidence that the
measured value corresponds to a sample free of that measurand
3.3
dew point
temperature below which the condensation of water vapour begins at the given pressure condition of the flue
gas
3.4
droplets
small liquid particles of condensed water vapour or water liquid in the flue gas (e.g. coming from a scrubber)
NOTE In adiabatic equilibrium conditions, droplets could arise only if a gas stream is saturated with water.
3.5
measurand
particular quantity subject to measurement
[VIM 2.6]
3.6
measuring series
several successive measurements carried out at the same sampling plane and with the same process
operating conditions
[EN 13284-1]
3.7
repeatability in the laboratory
closeness of the agreement between the results of successive measurements of the same measurand carried
out under the same conditions of measurement
NOTE 1 Repeatability conditions include:
 same measurement procedure;
 same laboratory;
 same sampling equipment, used under the same conditions;
 same location;
 repetition over a short period of time.
NOTE 2 Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the results.
In this European Standard the repeatability is expressed as a value with a level of confidence of 95 %.
[VIM 3.6]
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SIST EN 14790:2005
EN 14790:2005 (E)
3.8
repeatability in the field
closeness of the agreement between the results of simultaneous measurements of the same measurand
carried out with two equipments under the same conditions of measurement
NOTE 1 These conditions include:
 same measurement procedure;
 two equipments, the performances of which are fulfilling the requirements of the reference method, used under the
same conditions;
 same location;
 implemented by the same laboratory;
 typically calculated on short periods of time in order to avoid the effect of changes of influence parameters
(e.g. 30 min).
NOTE 2 Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the results.
In this European Standard the repeatability under field conditions is expressed as a value with a level of
confidence of 95 %.
3.9
reproducibility in the field
closeness of the agreement between the results of simultaneous measurements of the same measurand
carried out with several equipments under the same conditions of measurement
NOTE 1 These conditions include:
 same measurement procedure;
 several equipments, the performances of which are fulfilling the requirements of the reference method, used under
the same conditions;
 same location;
 implemented by several laboratories.
NOTE 2 Reproducibility may be expressed quantitatively in terms of the dispersion characteristics of the results.
In this European Standard the reproducibility under field conditions is expressed as a value with a level of
confidence of 95 %.
3.10
sampling location
specific area close to the sampling plane where the measurement devices are set up
3.11
sampling plane
plane normal to the centreline of the duct at the sampling position
[EN 13284-1]
3.12
sampling point
specific position on a sampling line at which a sample is extracted
[EN 13284-1]
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SIST EN 14790:2005
EN 14790:2005 (E)
3.13
standard reference method (SRM)
measurement method recognised by experts and taken as a reference by convention, which gives, or is
presumed to give, the accepted reference value of the concentration of the measurand (3.5) to be measured
3.14
uncertainty
parameter associated with the result of a measurement, that characterises the dispersion of the values that
could reasonably be attributed to the measurand
3.14.1
standard uncertainty u
uncertainty of the result of a measurement expressed as a standard deviation u
3.14.2
expanded uncertainty U
quantity defining a level of confidence about the result of a measurement that may be expected to encompass
a specific fraction of the distribution of values that could reasonably be attributed to a measurand
U = k x u
NOTE In this European Standard, the expanded uncertainty is calculated with a coverage factor of k = 2, and with a
level of confidence of 95 %.
3.14.3
combined uncertainty u
c
standard uncertainty uc attached to the measurement result calculated by combination of several standard
uncertainties according to GUM
3.14.4
overall uncertainty U
c
expanded combined standard uncertainty attached to the measurement result calculated according to GUM
U = k x u
c c
3.15
uncertainty budget
calculation table combining all the sources of uncertainty according to ISO 14956 or ENV 13005 in order to
calculate the overall uncertainty of the method at a specified value
3.16
vapour pressure
pressure of water in vapour form
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SIST EN 14790:2005
EN 14790:2005 (E)
4 Principle
4.1 General
This European Standard describes the Standard Reference Method (SRM) for determining water vapour
content emitting to atmosphere from ducts and stacks. The specific components and the requirements for the
measuring system are described. A number of performance characteristics, together with associated minimum
performance criteria are specified for the measurement method (see Table 1 in 7.2). The overall uncertainty of
the method shall meet the specifications given in this European Standard.
The method described hereafter is appropriate when the flue gas is free of droplets.
Within the scope of this European Standard, it is assumed that gas streams in stacks or ducts are more or
less in adiabatic (thermodynamic) equilibrium. In those conditions, droplets can arise only if a gas stream is
saturated with water. When no droplets are present in the gas stream, the gas stream is then assumed to be
unsaturated with water. A gas sample is extracted at a constant rate from the stack. The water vapour of that
sample is subsequently trapped by adsorption or by condensation plus adsorption; the mass of the vapour is
then determined by weighing the mass gain of the trapping unit.
When droplets are present in the gas stream, the implementation of the method described in this European
Standard leads to an overestimation of the water vapour content. If the measured value is equal to or higher
than the expected value shown in the table in Annex A for saturated conditions at the temperature and
pressure of the flue gas, that means that the presence of droplets can lead to biased results; such results shall
be rejected.
In such cases, the evidence suggests that the gas stream is saturated with water vapour. Under these
conditions, the method is abridged to a determination of the gas temperature. Then, the water vapour
concentration is calculated from the theoretical mass of water vapour per unit of standard gas volume at
liquid-gas equilibrium, given the actual temperature, pressure and composition of the gas stream.
4.2 Adsorption or condensation/adsorption method
A measured quantity of sampled gas is extracted from the gas stream through a trapping unit, which meets
the specifications of efficiency (see 6.4.2). The mass gain of the trapping unit is measured and divided by the
volume sampled in order to determine the mass concentration of water vapour.
4.3 Temperature method
This method applies when gases are water saturated.
A temperature probe is placed in the gas stream saturated with water vapour, until it reaches equilibrium. The
amount of water vapour present in the gas is subsequently derived from the temperature, using a water liquid-
gas equilibrium chart or table (see Annex A).
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SIST EN 14790:2005
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5 Apparatus
5.1 General
A known volume of flue gas is extracted representatively from a duct or chimney during a certain period of
time at a controlled flow rate. A filter removes the dust in the sampled volume; thereafter the gas stream is
passed through a trapping unit. It is important that all parts of the sampling equipment upstream of the
trapping unit are heated and that the components shall not react with or absorb water vapour (e.g. stainless
steel, borosilicate glass, quartz glass, PTFE or titanium are suitable materials).
An example of suitable sampling trains are shown in Annex B. The user can choose between a trapping unit
made up with either:
 adsorption unit (Figure B.1); or
 condensation and an adsorption unit (Figure B.2).
The choice shall be made to fulfil the efficiency that is required in 6.4.2.
5.2 Sampling probe
In order to access the representative measurement point(s) of the sampling plane, probes of different lengths
and inner diameters may be used. The design and configuration of the probe used shall ensure the residence
time of the sample gas within the probe is minimised.
The procedure of clause 6.2.2 can be used when the operator suspects that the flue gas is inhomogeneous.
The probe may be marked before sampling in order to demonstrate that the representative measurement
point(s) in the measurement plane has (have) been reached.
The sampling probe shall be surrounded by a heating jacket capable of producing a controlled temperature of
at least 120 °C and 20 °C higher than the (acid) dew point of gases and shall be protected and positioned
using an outer tube.
NOTE 1 It is possible to perform the sampling of SO and water vapour simultaneously with the same probe (without
2
nozzle providing no droplets are present).
NOTE 2 It is possible to perform the sampling of HCl and water vapour simultaneously with the same probe (without
nozzle providing no droplets are present).
5.3 Filter housing
The filter housing shall be made of materials inert to water vapour and shall have the possibility to be
connected with the probe thereby avoiding leaks.
The filter housing may be located either:
 in the duct or chimney, mounted directly behind the entry nozzle (in-stack filtration); or
 outside the duct or chimney, mounted directly behind the suction tube (out-stack filtration).
The filter holder shall be connected to the probe without any cold path between the two.
NOTE In special cases where the sample gas temperature is > 200 °C, the heating jacket around the sampling probe,
filter holder and connector fine may be omitted. However the temperature in the sampled gas just after the filter housing
should not fall below the acid dew point temperature.
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SIST EN 14790:2005
EN 14790:2005 (E)
5.4 Particle filter
Particle filters and filter housings of different designs may be used, but the residence time of the sample gas
should be minimised.
5.5 Trapping unit
The trapping unit shall be made up with:
 adsorption unit; or
 condensation and an adsorption unit.
a) When using the adsorption unit alone, it shall consist of at least one cartridge, impinger or absorber, filled
with a suitable drying agent, for example: coloured silica gel.
b) Condensation and adsorption unit shall consist of two stages:
1) the first one shall be a condensation stage with an optional cooling system;
2) the second one shall be an adsorption stage as described in a).
The temperature at the outlet of the condensation unit shall be as low as possible.
The efficiency of the sampling system shall be checked according to the procedure described in 6.4.2.
NOTE The trapping efficiency can be increased by increasing the residence time of sampled gases in the trapping
unit and/or by improving the efficiency of the cooling system. The sampled volume should be sufficient to reach an
appropriate accuracy of the measurement (see clause 5.8 and 7).
Condensation of water shall be avoided in all parts of the sampling system that are not weighed.
5.6 Cooling System (optional)
Any kind of cooling system may be used to condense water vapour in the sampled flue gas (e.g. crushed ice
or cryogenic system).
5.7 Sampling pump
A leak-free pump capable of drawing sample gas at a set flow-rate is required.
NOTE 1 A rotameter (optional) could make easier the adjustment of the nominal sampling flow-rate.
NOTE 2 A small surge tank may be used between the pump and rotameter to eliminate the pulsation effect of the
diaphragm pump on the rotameter.
NOTE 3 A regulating valve (optional) would also be useful for adjusting the sample gas flow-rate.
5.8 Gas volume meter
Two variants of gas volume meter may be used:
 dry-gas volume meter; or
 wet-gas volume meter.
a) Gas volume meter (wet or dry) shall have a relative uncertainty not exceeding ± 2,0 % of the measured
volume (actual conditions).
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SIST EN 14790:2005
EN 14790:2005 (E)
The gas volume meter shall be equipped with a temperature measuring device (uncertainty less than ± 2,5 K)
and shall be associated to an absolute pressure measurement (uncertainty less than ± 1,0 %).
b) When using a dry gas volume meter, a condenser and/or a gas drying system shall be used which can
3
achieve a residual water vapour content of less than 10,0 g/m (equivalent to a dew point of 10,5 °C or a
volume content χ(H O) = 1,25 %).
2
NOTE For example, a glass cartridge or
...