SIST EN 14790:2017

SLOVENSKI STANDARD
oSIST prEN 14790:2015
01-januar-2015
(PLVLMHQHSUHPLþQLKYLURY'RORþHYDQMHYRGQHSDUHYRGYRGQLNLK6WDQGDUGQD
UHIHUHQþQDPHWRGD
Stationary source emissions - Determination of the water vapour in ducts - Standard
reference method
Emissionen aus stationären Quellen - Bestimmung von Wasserdampf in Leitungen -
Standardreferenzverfahren
Emissions de sources fixes - Détermination de la vapeur d'eau dans les conduits -
Méthode de référence normalisée
Ta slovenski standard je istoveten z: prEN 14790
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
oSIST prEN 14790:2015 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN 14790:2015

---------------------- Page: 2 ----------------------
oSIST prEN 14790:2015

EUROPEAN STANDARD
DRAFT
prEN 14790
NORME EUROPÉENNE

EUROPÄISCHE NORM

October 2014
ICS 13.040.40 Will supersede EN 14790:2005
English Version
Stationary source emissions - Determination of the water vapour
in ducts - Standard reference method
Emissions de sources fixes - Détermination de la vapeur Emissionen aus stationären Quellen - Bestimmung von
d'eau dans les conduits - Méthode de référence normalisée Wasserdampf in Kanälen - Standardreferenzverfahren
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.

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: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 14790:2014 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
Contents
Page
Foreword .3
1 Scope .4
2 Normative references .4
3 Terms and definitions .4
4 Measuring principle .8
5 Description of measuring equipment .8
6 Performance characteristics of the SRM . 11
7 Equivalence of an alternative method . 12
8 Measurement procedure . 12
9 Water vapour determination . 15
10 Report . 16
Annex A (informative) Evaluation of the method in the field . 17
Annex B (normative) Determination of water vapour concentration for water saturated gas, at
P = 101,325 kPa . 21
std
Annex C (informative) Type of sampling equipments . 23
Annex D (informative) Example of assessment of compliance of standard reference method for
water vapour with requirements on emission measurements . 24
Annex E (informative) Significant technical changes . 35
Bibliography . 36


2

---------------------- Page: 4 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
Foreword
This document (prEN 14790:2014) 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 14790:2005.
Annex E provides details of significant technical changes between this document and the previous edition.
3

---------------------- Page: 5 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
1 Scope
This European Standard specifies the standard reference method (SRM) based on a sampling system with a
condensation/adsorption technique to determine the water vapour concentration in the flue gases emitted to
atmosphere from ducts and stacks.
This European Standard specifies the performance characteristics to be determined and performance criteria
to be fulfilled by measuring systems based on the measurement method. It applies to periodic monitoring and
to the calibration or control of automated measuring systems (AMS) permanently installed on a stack, for
regulatory or other purposes.
This European Standard specifies criteria for demonstration of equivalence of an alternative method to the
SRM by application of prEN 14793.
This European Standard is applicable in the range of water vapour content from 4 % to 40 % as volume
3 3
concentrations and of water vapour mass 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.
In this European Standard all the concentrations are expressed at standard conditions (273 K and 101,3 kPa).
NOTE 1 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.
This European Standard has been evaluated during field tests on waste incineration, co-incineration and large
combustion plants. It has been validated for sampling periods of 30 min in the volume concentration range of
7 % to 26 %.
NOTE 2 The characteristics of installations, the conditions during field tests and the values of repeatability and
reproducibility in the field are given in Annex A.
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 1911, Stationary source emissions — Determination of mass concentration of gaseous chlorides
expressed as HCl — Standard reference method
prEN 14791, Stationary source emissions — Determination of mass concentration of sulphur oxides —
Standard reference method
prEN 14793:2014, Stationary source emission – Demonstration of equivalence of an alternative method with a
reference method
EN 15259:2007, Air quality — Measurement of stationary source emissions — Requirements for
measurement sections and sites and for the measurement objective, plan and report
ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
absorber
device in which water vapour is absorbed
4

---------------------- Page: 6 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
3.2
dew point
temperature below which the condensation of water vapour begins at the given pressure condition of the flue
gas
3.3
droplets
small liquid particles of condensed water vapour or water liquid in the flue gas (e.g. coming from a scrubber)
Note 1 to entry: In adiabatic equilibrium conditions, droplets could arise only if a gas stream is saturated with water.
3.4
measurand
particular quantity subject to measurement
[SOURCE: JCGM 200:2012]
3.5
measurement series
several successive measurements carried out on the same measurement plane and at the same process
operating conditions
3.6
measurement plane
plane normal to the centre line of the duct at the sampling position
Note 1 to entry: Measurement plane is also known as sampling plane.
[SOURCE: EN 15259]
3.7
measurement point
position in the measurement plane at which the sample stream is extracted or the measurement data are
obtained directly
Note 1 to entry: Measurement point is also known as sampling point.
[SOURCE: EN 15259]
3.8
measurement site
place on the waste gas duct in the area of the measurement plane(s) consisting of structures and technical
equipment, for example working platforms, measurement ports, energy supply
Note 1 to entry: Measurement site is also known as sampling site.
[SOURCE: EN 15259]
3.9
reference method
RM
measurement method taken as a reference by convention, which gives the accepted reference value of the
measurand
Note 1 to entry: A reference method is fully described.
Note 2 to entry: A reference method can be a manual or an automated method.
Note 3 to entry: Alternative methods can be used if equivalence to the reference method has been demonstrated.
[SOURCE: EN 15259:2007]
5

---------------------- Page: 7 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
3.10
standard reference method
SRM
reference method prescribed by European or national legislation
[SOURCE: EN 15259:2007]
3.11
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 to entry: 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 to entry: Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the results.
Note 3 to entry: In this European Standard the repeatability is expressed as a value with a level of confidence of 95 %.
[SOURCE: JCGM 200:2012]
3.12
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 to entry: 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 to entry: Repeatability can be expressed quantitatively in terms of the dispersion characteristics of the results.
Note 3 to entry: In this European Standard the repeatability under field conditions is expressed as a value with a level
of confidence of 95 %.
6

---------------------- Page: 8 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
3.13
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 to entry: 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 to entry: Reproducibility can be expressed quantitatively in terms of the dispersion characteristics of the results.
Note 3 to entry: In this European Standard the reproducibility under field conditions is expressed as a value with a level
of confidence of 95 %.
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
3.15
standard uncertainty
u
uncertainty of the result of a measurement expressed as a standard deviation
3.16
combined uncertainty
u
c
standard uncertainty attached to the measurement result calculated by combination of several standard
uncertainties according to the principles laid down in ISO/IEC Guide 98-3 (GUM)
3.17
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× u

Note 1 to entry: In this European Standard, the expanded uncertainty is calculated with a coverage factor of k = 2, and
with a level of confidence of 95 %.
Note 2 to entry: The expression overall uncertainty is sometimes used to express the expanded uncertainty.
3.18
uncertainty budget
calculation table combining all the sources of uncertainty according to EN ISO 14956 or ISO/IEC Guide 98-3
in order to calculate the combined uncertainty of the method at a specified value
3.19
vapour pressure
pressure of water in vapour form
7

---------------------- Page: 9 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
4 Measuring principle
4.1 General
This European Standard describes the standard reference method (SRM) for determining the water-vapour
content emitted 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
performance criteria are specified for the measurement method (see Table 1 in 6). The expanded 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 system.
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 B 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 system, which meets
the specifications of efficiency (see 8.4.2). The mass gain of the trapping system is measured in order to
determine the mass or the volumic water vapour content, on the basis of the volume sampled.
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 B).
5 Description of measuring equipment
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 system. It is important that all parts of the sampling equipment upstream of the
trapping system 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).
8

---------------------- Page: 10 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
An example of suitable sampling trains is shown in Annex C. The user can choose between a trapping system
made up with either:
 adsorption system (Figure B.1); or
 condensation and an adsorption system (Figure B.2).
The choice shall be made to fulfil the efficiency that is required in 8.4.2.
5.2 Sampling probe
In order to reach the measurement point(s) of the measurement 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 in order to reduce the response time of the measuring system.
NOTE 1 The probe can be marked before sampling in order to demonstrate that the measurement points in the
measurement plane 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 2 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 3 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 greater than 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.
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 system
The trapping system shall be made up with:
 adsorption system; or
 condensation and an adsorption system.
9

---------------------- Page: 11 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
a) When using the adsorption system 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 system 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 system shall be as low as possible.
The efficiency of the sampling system shall be checked according to the procedure described in 8.4.2.
NOTE The trapping efficiency can be increased by increasing the residence time of sampled gases in the trapping
system 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 5.8 and 6).
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 can 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).
The gas volume meter shall be equipped with a temperature measuring device with an uncertainty of
calibration less than 2,5 K and shall be associated to an absolute pressure measurement with an
uncertainty of calibration 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 adsorption bottle packed with silica gel (1 mm to 3 mm particle size) which
has been previously dried at least at 110 °C for at least 2 h.
When using a wet gas volume meter, a correction shall be applied for water vapour, using the table in
Annex B.
10

---------------------- Page: 12 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
5.9 Barometer
Barometer capable of measuring atmospheric pressure present at the measurement site, with an expanded
uncertainty that does not exceed 1 kPa.
5.10 Balance
The resolution of the balance shall be equal or better than 0,1 g or 2,0 % of the water weight to be measured.
5.11 Temperature measurement
Calibrated thermometer for flue gas temperature determination with a measuring range from 273 K to 373 K,
with an uncertainty of 2,5 K or better. That thermometer shall have a low thermal inertia, in order to be rapidly
in thermal equilibrium with the stack gas.
6 Performance characteristics of the SRM
Table 1 gives an overview of the minimum performance characteristics of the whole method. The laboratory
implementing the method shall demonstrate that:
 performance characteristics of the method given in Table 1 are better than the performance criteria; and
 expanded uncertainty calculated by combining values of selected performance characteristics by means
of an uncertainty budget is less than 20,0 % at the daily emission limit value (ELV) or at the lower limit
value fixed to the plant by the local authorities.
Table 1 — Minimum performance characteristics of the SRM to be determined
in laboratory tests (LT) and field tests (FT) and associated performance criteria
Performance characteristic LT FT Performance criterion

Volume gas meter:
a
uncertainty ≤ 2,0 % of the volume of sampled
sample volume
a
b
X
gas
a
b
temperature
a

X
uncertainty ≤ 2,5 K
a
uncertainty ≤ 1,0 % of the absolute
absolute pressure
a
b

X


pressure
Leak in the sampling line X ≤ 2,0 % of the nominal flow rate
Weighing of collected water:
c
uncertainty associated to the balance
X X
d
repeatability in the field of weighing
X
a
The uncertainty of sampling volume gas is a combination of uncertainties due to calibration, resolution, reading and drift.
The uncertainty related to the temperature and absolute pressure of the gas meter is a combination of the uncertainties due
to calibration, resolution, reading, drift and repeatability. When a barometer is used see 5.9.
b
Performance criteria correspond to the uncertainty of calibration.
c
The uncertainty contributions of the balance can be for example: linearity of balance, resolution, reading and calibration
tare. See 5.10.
d
When weighing is carried out in the field, variations of ambient conditions can be an uncertainty source, for example
temperature variations, air currents and vibrations.

11

---------------------- Page: 13 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
The principle of calculation of the expanded uncertainty is based on the law on propagation of uncertainty laid
down in ISO/IEC Guide 98-3 (GUM):
 determine the standard uncertainties attached to the performance characteristics to be included in the
calculation of the uncertainty budget by means of laboratory or field tests, and according to
ISO/IEC Guide 98-3;
 calculate the uncertainty budget by combining all the standard uncertainties according to
ISO/IEC Guide 98-3, and taking the variations range of the influence quantities of the specific site
conditions into account;
 all the components of standard uncertainties that are less than 5 % relative of the maximum standard
uncertainty can be neglected;
 calculate the expanded uncertainty at the measured value.
An example of the evaluation of the expanded uncertainty is given in Annex D.
7 Equivalence of an alternative method
In order to show that an alternative method is equivalent to the standard reference method specified in this
European Standard, follow the procedures described in prEN 14793.
The maximum allowable standard deviation of repeatability expressed as a percentage value for this standard
reference method is:
(1)
(C)= 0,0262C+ 0,30 %
s
r,limit
where
C is the volume concentration in %.
The standard deviation of reproducibility expressed as a percentage value for this standard reference method
is:
s (C)= 0,03C+ 0,367 % (2)
R
where
C is the volume concentration in %.
8 Measurement procedure
8.1 General requirements
The sample and the measurement point shall be representative of the emission of the process.
The following points should be considered when sampling:
 nature of the plant process e.g. steady state or discontinuous. If possible the sampling and measuring
programme should be carried out under steady operating conditions at the plant;
 expected concentration to be measured and any required averaging period, both of which can influence
the measuring and sampling time.
The minimum sampling period is 30 min and the minimum sample gas volume is 50 l. When the expected
mass concentration of water vapour is low, the sampling period or the sampling volume may be extended.
12

---------------------- Page: 14 ----------------------
oSIST prEN 14790:2015
prEN 14790:2014 (E)
8.2 Preparation and installation of equipment
8.2.1 Measurement site and measurement plane
The measurement site is chosen to ensure that the gas concentrations measured are representative of the
average conditions in the gas duct. In addition, the measurement site shall be chosen with regard to safety of
the personnel, accessibility and availability of electrical power.
The location is chosen in accordance with 6.2.1 of EN 15259.
8.2.2 Measurement point(s)
It is necessary to ensure that the gas concentrations measured are representative of the average conditions
inside the waste gas duct. Measurements may be performed at one representative measurement-point or at
any measurement point, if the corresponding requirements on the distribution of the oxygen volume-
concentration specified in 8.3 of EN 15259 are fulfilled. In all other cases the measurements shall be
performed as grid measurement
...