SIST EN ISO 23210:2010
(Main)Stationary source emissions - Determination of PM10/PM2,5 mass concentration in flue gas - Measurement at low concentrations by use of impactors (ISO 23210:2009)
Stationary source emissions - Determination of PM10/PM2,5 mass concentration in flue gas - Measurement at low concentrations by use of impactors (ISO 23210:2009)
This International Standard specifies a standard reference method for the determination of PM10 and PM2,5 mass concentrations at stationary emission sources by use of two-stage inpactors. The measurement method is especially suitable for measurements of mass concentrations below 40 mg/m3 as half-hourly averages at standard conditions (273 K, 1013 hPa, dry gas). It is an acceptable method for the measurement in the flue gas of different installations such as cement and steel production as well as combustion processes. This International Standard is not applicable to sampling of flue gases that are saturated with water-vapour. This International Standard is not applicable where the majority of the particles are likely to exceed PM10 e.g. in case of raw gases or plant operating failures. This International Standard may not be used for the determination of the total mass concentration of dust. This International Standard describes the design, use and theory of round-nozzle impactors. It does not exclude other types of impactors, provided these systems meet the performance criteria specified in this International Standard in a validation of the impactor performed by an independent testing laboratory.
Emissionen aus stationären Quellen - Ermittlung der Massenkonzentration von PM10/PM2,5 im Abgas - Messung bei niedrigen Konzentrationen mit Impaktoren (ISO 23210:2009)
Diese Internationale Norm legt ein Standardreferenzmessverfahren zur Ermittlung der PM10- und PM2,5-Massenkonzentrationen an geführten stationären Quellen mit Hilfe eines zweistufigen Impaktors fest. Das Messverfahren ist insbesondere zur Messung von Massenkonzentrationen unterhalb von 50 mg/m3 auf der Basis von Halbstundenmittelwerten und im Normzustand (273 K, 1013 hPa, trockenes Gas) geeignet. Es hat sich bei der Messung in Abgasen unterschiedlicher Anlagen bewährt, beispielsweise bei Anlagen zur Herstellung von Zement und Stahl sowie bei Verbrennungsprozessen.
Diese Internationale Norm ist nicht anwendbar bei mit Wasserdampf gesättigten Abgasen.
Diese Internationale Norm ist nicht anwendbar, wenn die Mehrzahl der Partikel offensichtlich größer als PM10 ist, beispielsweise bei Rohgasmessungen oder Betriebsstörungen der Anlage.
ANMERKUNG 1 Messungen bei Staubkonzentrationen oberhalb von 50 mg/m3 als Halbstundenmittelwert im Normzustand (273 K, 1013 hPa, trockenes Gas) können zu einer Überladung der Sammelplatten und des Endfilters und auch zu kürzeren Sammelzeiten führen.
ANMERKUNG 2 Die Sammelplatten und Endfilter können für weitere chemische Analysen verwendet werden.
Diese Internationale Norm darf nicht zur Ermittlung der Gesamtstaubmassenkonzentration herangezogen werden.
ANMERKUNG 3 Zur Beurteilung der Daten kann es sinnvoll sein, zeitgleich zu den PM10- und PM2,5-Messungen auch Gesamtstaubmessungen durchzuführen.
Émissions de sources fixes - Détermination de la concentration en masse de PM10/PM2,5 dans les effluents gazeux - Mesurage à des faibles concentrations au moyen d'impacteurs (ISO 23210:2009)
L'ISO 23210:2009 spécifie une méthode de référence permettant de déterminer la concentration en masse de particules PM10 et PM2,5 au niveau de sources d'émissions fixes au moyen d'impacteurs à deux étages. La méthode est particulièrement adaptée au mesurage de concentrations en masse inférieures à 40 mg/m3 sous forme de moyennes toutes les demi-heures dans des conditions normales (273 K, 1 013 hPa, gaz sec). Il s'agit d'une méthode applicable au mesurage des effluents gazeux émis par différentes installations, telles que les installations de production de ciment et d'acier ainsi que par les procédés de combustion.
L'ISO 23210:2009 n'est pas applicable à l'échantillonnage de fumées saturées de vapeur d'eau.
L'ISO 23210:2009 n'est pas applicable lorsque la majorité des particules est susceptible de dépasser PM10, par exemple dans le cas de gaz bruts ou de dysfonctionnements de l'installation.
L'ISO 23210:2009 ne permet pas de déterminer la concentration totale en masse de poussières.
L'ISO 23210:2009 décrit la conception, l'utilisation ainsi que la théorie des impacteurs à buse ronde. Les autres types d'impacteurs ne sont pas exclus à condition que ces systèmes répondent aux critères de performance indiqués dans l'ISO 23210:2009 dans une validation de l'impacteur réalisée par un laboratoire d'essais indépendant.
Emisije nepremičnih virov - Določevanje masne koncentracije PM10/PM2,5 v odpadnih plinih - Meritve pri nizkih koncentracijah z uporabo impaktorjev (ISO 23210:2009)
Ta mednarodni standard določa standardno referenčno metodo za določevanje masne koncentracije PM10 in PM2,5 v stacionarnih emisijskih virih z uporabo dvostopenjskih impaktorjev. Merilna metoda je primerna predvsem za masne koncentracije pod 40 mg/m3 kot polurna povprečja pri standardnih pogojih (273 K, 1013 hPa, suhi plin). Je sprejemljiva metoda za meritve v odpadnih plinih različnih objektov, kot so proizvodnja cementa in jekla ter procesi zgorevanja. Ta mednarodni standard ne velja za vzorčenje odpadnih plinov, ki so nasičeni z vodno paro. Ta mednarodni standard ne velja tam, kjer je verjetno, da večina delcev presega PM10, npr. v primeru neočiščenih plinov ali okvar delovanja obrata. Ta mednarodni standard se ne more uporabiti za določevanje skupne masne koncentracije prahu. Ta mednarodni standard opisuje zasnovo, uporabo in teorijo impaktorjev z zaobljeno razpršilno šobo. Ne izključuje drugih vrst impaktorjev, če ti sistemi ustrezajo merilom za zmogljivost, določenim v tem mednarodnem standardu, pri validaciji impaktorja, ki jo opravi neodvisen preskusni laboratorij.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 23210:2010
01-februar-2010
(PLVLMHQHSUHPLþQLKYLURY'RORþHYDQMHPDVQHNRQFHQWUDFLMH3030Y
RGSDGQLKSOLQLK0HULWYHSULQL]NLKNRQFHQWUDFLMDK]XSRUDERLPSDNWRUMHY ,62
Stationary source emissions - Determination of PM10/PM2,5 mass concentration in flue
gas - Measurement at low concentrations by use of impactors (ISO 23210:2009)
Emissionen aus stationären Quellen - Ermittlung der Massenkonzentration von
PM10/PM2,5 im Abgas - Messung bei niedrigen Konzentrationen mit Impaktoren (ISO
23210:2009)
Émissions de sources fixes - Détermination de la concentration en masse de
PM10/PM2,5 dans les effluents gazeux - Mesurage à des faibles concentrations au
moyen d'impacteurs (ISO 23210:2009)
Ta slovenski standard je istoveten z: EN ISO 23210:2009
ICS:
13.040.40 (PLVLMHQHSUHPLþQLKYLURY Stationary source emissions
SIST EN ISO 23210:2010 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 23210:2010
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SIST EN ISO 23210:2010
EUROPEAN STANDARD
EN ISO 23210
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 13.040.40
English Version
Stationary source emissions - Determination of PM10/PM2,5
mass concentration in flue gas - Measurement at low
concentrations by use of impactors (ISO 23210:2009)
Émissions de sources fixes - Détermination de la Emissionen aus stationären Quellen - Ermittlung der
concentration en masse de PM10/PM2,5 dans les effluents Massenkonzentration von PM10/PM2,5 im Abgas -
gazeux - Mesurage à des faibles concentrations au moyen Messung bei niedrigen Konzentrationen mit Impaktoren
d'impacteurs (ISO 23210:2009) (ISO 23210:2009)
This European Standard was approved by CEN on 20 June 2009.
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 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 Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 23210:2009: E
worldwide for CEN national Members.
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SIST EN ISO 23210:2010
EN ISO 23210:2009 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 23210:2010
EN ISO 23210:2009 (E)
Foreword
This document (EN ISO 23210:2009) has been prepared by Technical Committee ISO/TC 146 "Air quality" in
collaboration with 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 February 2010, and conflicting national standards shall be withdrawn
at the latest by February 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 23210:2009 has been approved by CEN as a EN ISO 23210:2009 without any modification.
3
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SIST EN ISO 23210:2010
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SIST EN ISO 23210:2010
INTERNATIONAL ISO
STANDARD 23210
First edition
2009-08-01
Stationary source emissions —
Determination of PM /PM mass
10 2,5
concentration in flue gas — Measurement
at low concentrations by use of
impactors
Émissions de sources fixes — Détermination de la concentration en
masse de PM /PM dans les effluents gazeux — Mesurage à des
10 2,5
faibles concentrations au moyen d'impacteurs
Reference number
ISO 23210:2009(E)
©
ISO 2009
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
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Published in Switzerland
ii © ISO 2009 – All rights reserved
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols and abbreviated terms . 3
5 Principle of the method. 5
6 Specification of the two-stage impactor. 8
7 Sampling train . 11
8 Preparation, measurement procedure and post-treatment. 13
9 Calculation of the results. 17
10 Performance characteristics . 17
11 Reporting . 20
Annex A (normative) Calculation of the sample volumetric flow rate of the impactor. 21
Annex B (informative) General equations concerning impaction theory . 28
Annex C (informative) Results of method validation. 30
Annex D (informative) Influence of variations in the flue gas temperature and flue gas
composition on the Reynolds number . 36
Annex E (informative) Entry nozzle . 38
Annex F (informative) Equipment list. 39
Annex G (normative) Determination of a representative sampling point. 41
Bibliography . 42
© ISO 2009 – All rights reserved iii
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 23210 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 1, Stationary
source emissions.
iv © ISO 2009 – All rights reserved
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
Introduction
In order to quantify the amount of PM and PM particles in stationary source emissions or to identify the
10 2,5
contribution sources of PM and PM in ambient air, it is necessary to measure fine particulate matter in the
10 2,5
flue gas of industrial sources.
This International Standard describes a measurement method for the determination of mass concentrations of
PM and PM emissions, which realizes the same separation curves as those specified in ISO 7708:1995
10 2,5
for PM and PM in ambient air. The method is based on the principle of impaction. During sampling, the
10 2,5
particle fraction is divided into three groups with aerodynamic diameters greater than 10 µm, between 10 µm
and 2,5 µm and smaller than 2,5 µm.
The measurement method allows the simultaneous determination of concentrations of PM and PM
10 2,5
emissions. The method is designed for stack measurements at stationary emission sources.
The contribution of stationary source emissions to PM and PM concentrations in ambient air can be
10 2,5
classified as primary and secondary. Those emissions that exist as particulate matter within the stack gas and
that are emitted directly to air can be considered “primary”. Secondary particulate consists of those emissions
that form in ambient air due to atmospheric chemical reactions. The measurement technique in this
International Standard does not measure the contribution of stack emissions to the formation of secondary
particulate matter in ambient air.
This International Standard includes normative references to ISO 12141:2002. The corresponding
requirements in ISO 12141:2002 are identical to those in European Standards EN 13284-1:2001 and
EN 15259:2007.
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SIST EN ISO 23210:2010
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SIST EN ISO 23210:2010
INTERNATIONAL STANDARD ISO 23210:2009(E)
Stationary source emissions — Determination
of PM /PM mass concentration in flue gas — Measurement
10 2,5
at low concentrations by use of impactors
1 Scope
This International Standard specifies a standard reference method for the determination of PM and PM
10 2,5
mass concentrations at stationary emission sources by use of two-stage impactors. The measurement method
3
is especially suitable for measurements of mass concentrations below 40 mg/m as half-hourly averages in
standard conditions (273 K, 1 013 hPa, dry gas). It is an acceptable method for the measurement in the flue
gas of different installations, such as cement and steel production plants, as well as combustion processes.
This International Standard is not applicable to the sampling of flue gases that are saturated with water vapour.
This International Standard is not applicable where the majority of the particles are likely to exceed PM , for
10
example, in the case of raw gases or plant operating failures.
3
NOTE 1 Measurements of particulate concentrations higher than 40 mg/m , as a half-hourly average in standard
conditions (273 K, 1 013 hPa, dry gas), can lead to overloading of the collecting plates and backup filters and also could
result in shorter sampling times.
NOTE 2 The collecting plates and backup filters can be used for further chemical analysis.
This International Standard cannot be used for the determination of the total mass concentration of dust.
NOTE 3 For data assessment purposes, it can be useful to perform measurements of total particulate matter in parallel
to the PM and PM measurements.
10 2,5
This International Standard describes the design, use and theory of round-nozzle impactors. It does not
exclude other types of impactors, provided these systems meet the performance criteria specified in this
International Standard in a validation of the impactor performed by an independent testing laboratory.
2 Normative references
The following referenced documents are indispensable for the application 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.
ISO 7708:1995, Air quality — Particle size fraction definitions for health-related sampling
ISO 12141:2002, Stationary source emissions — Determination of mass concentration of particulate matter
(dust) at low concentrations — Manual gravimetric method
ISO 20988:2007, Air quality — Guidelines for estimating measurement uncertainty
© ISO 2009 – All rights reserved 1
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Flow-related terms
3.1.1
aerodynamic diameter
3
diameter of a sphere of density 1 g/cm with the same terminal velocity due to gravitational force in calm air as
the particle, under prevailing conditions of temperature, pressure and relative humidity
NOTE Adapted from ISO 7708:1995, 2.2.
3.1.2
cut-off diameter
aerodynamic diameter where the separation efficiency of the impactor stage is 50 %
3.1.3
PM
10
particles which pass through a size-selective inlet with a 50 % efficiency cut-off at 10 µm aerodynamic
diameter
NOTE PM corresponds to the “thoracic convention” as defined in ISO 7708:1995, Clause 6.
10
3.1.4
PM
2,5
particles which pass through a size-selective inlet with a 50 % efficiency cut-off at 2,5 µm aerodynamic
diameter
NOTE PM corresponds to the “high-risk respirable convention” as defined in ISO 7708:1995, 7.1.
2,5
3.1.5
Reynolds number
dimensionless parameter describing a flow
3.1.6
Stokes's number
dimensionless instrument-specific quantity
NOTE See B.2.
3.1.7
Cunningham factor
correction factor taking into account the change in the interaction between particles and the gas phase
NOTE Stokes's law is based on the assumption that the relative gas velocity at the particle edge equals zero. This
assumption is not valid for particle sizes close to the mean free path length. Such particles cannot move continuously due
to collisions with particles and gas atoms. In this case, Stokes's law has to be amended by a correction factor, i.e. the
Cunningham factor. This factor only depends on the mean free path length and the particle diameter.
3.1.8
Sutherland constant
constant characteristic of a gas used for calculating the dependence of the viscosity of a gas on its
temperature
3.1.9
aerosol
suspension in a gaseous medium of solid particles, liquid particles or solid and liquid particles having a
negligible falling velocity
[ISO 4225:1994, 3.2]
2 © ISO 2009 – All rights reserved
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
3.2 Instrument-related terms
3.2.1
filter set
separator consisting of two collecting plates and a backup filter
3.2.2
collecting plate
plane filter used for particle collection by impaction
3.2.3
backup filter
plane filter used for collection of the PM particle fraction
2,5
3.2.4
collecting plate holder
support of the collecting plate
3.2.5
backup filter holder
punched plate as support of the backup filter
3.2.6
diffuser
conical part in front of the nozzle plates to avoid stall
3.3 Sampling-related terms
3.3.1
measurement site
sampling site
place on the waste gas duct in the area of the measurement plane(s) consisting of structures and technical
equipment
NOTE The measurement site consists, for example, of working platforms, measurement ports and energy supply.
3.3.2
measurement section
region of the waste gas duct which includes the measurement plane(s) and the inlet and outlet sections
3.3.3
measurement plane
sampling plane
plane normal to the centreline of the duct at the sampling position
4 Symbols and abbreviated terms
A separation efficiency
BF backup filter
c ith concentration value of the first measuring system
1,i
c ith concentration value of the second measuring system
2,i
C Cunningham factor
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
CP2 collecting plate of the second impactor stage
d aerodynamic diameter
ae
d equivalent volumetric diameter
e
d impactor nozzle diameter
in
d entry nozzle diameter
nozzle
d cut-off diameter
50
E collection efficiency
f mass concentration of water vapour in standard conditions and with dry gas
n
g acceleration due to gravity
i series element number, i = 1, 2, 3, … m
j series element number, j = 1, 2, 3, … n
l impactor nozzle length
in
m sampled mass
m(BF) particle mass on the backup filter
m(CP2) particle mass on the collecting plate of the second impactor stage
M molar mass
n number of measurement pairs
N number of impactor nozzles
p absolute gas pressure
p atmospheric pressure at the measurement site (barometric pressure)
atm
p standard pressure
n
p difference between the static pressure in the measurement cross-section and the atmospheric
st
pressure at the measurement site
r volume fraction
R gas constant
Re Reynolds number
s distance between the end of the nozzle and the impactor plate
s standard deviation of paired measurements
D
S Sutherland constant
St Stokes's number
4 © ISO 2009 – All rights reserved
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
T gas temperature
T standard temperature
n
T critical temperature
crit
v flue gas velocity
fg
v gas velocity in the impactor nozzle
in
v gas velocity in the entry nozzle
nozzle
v particle drift rate
P
V sample volume
V sample volume in standard conditions and for dry gas
n
V volumetric flow rate
WV water vapour
λ mean free path length
χ dynamic shape factor for non-spherical particles
η dynamic viscosity of the gas
ρ density of the dry gas in standard conditions
n
ρ density of water vapour in standard conditions
n,WV
ρ density of the gas in operating conditions
p,t,h
ρ particle mass density
P
ρ particle unit mass density
0,P
5 Principle of the method
5.1 General
In particle measurements, the following three relevant physical characteristics can be distinguished:
⎯ mass concentration (e.g. total dust, PM , PM ) and distribution of mass fractions;
10 2,5
⎯ particle number concentration and particle size distribution by number concentration;
⎯ morphology of particles (e.g. shape, colour, optical properties).
The PM and PM mass concentrations are determined by size-selective separation of gas-borne particles
10 2,5
by use of the different inertia of particles. In general, two methods of separation based on the inertia principle
can be distinguished:
⎯ impactors (sub-types: e.g. slot-type nozzle impactor, round-nozzle impactor, virtual impactor);
⎯ cyclones (sub-types: e.g. cascade cyclone, sharp-cut cyclone).
Impactors are used at low mass concentrations, whereas cyclones are applied at high mass concentrations.
This International Standard specifies a measurement method for the determination of PM and PM mass
10 2,5
concentrations based on impaction with a round-nozzle impactor.
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
5.2 Theory of impaction
An impactor separates particles according to their specific aerodynamic diameter. The aerosol is accelerated
through a nozzle and then deflected by 90°. Particles with greater aerodynamic diameters are not able to
follow the gas flow due to their mass inertia. They are impacted on the collecting plate (see Figure 1).
Key
1 impactor nozzle l impactor nozzle length
in
2 flow line s distance between nozzle outlet and collecting plate
3 particle remaining in the flow d impactor nozzle diameter
in
4 impacted particle
5 particle trajectory
6 nozzle plate
7 collecting plate
Figure 1 — Principle of impaction
An impactor stage is defined by the so-called cut-off diameter d . For particles with this aerodynamic
50
diameter, the separation efficiency of the impactor is 50 %. Equation (1) is used to calculate the cut-off
diameter d of a single-stage round-nozzle impactor (see Reference [11] in the Bibliography):
50
3
9π St ηNd
50 in
d = (1)
50
4ρ CV
0,P
where
St is the Stokes's number in relation to the cut-off diameter d ;
50 50
η is the dynamic viscosity of the gas;
N is the number of impactor nozzles;
d is the impactor nozzle diameter;
in
3
ρ is the particle unit mass density (1 g/cm );
0,P
C is the Cunningham factor;
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
V is the volumetric flow rate through the impactor in operating conditions.
The following conditions apply to the design and to the application of Equation (1):
a) Distance between nozzle and collecting plate
The ratio of the distance s between the nozzle outlet and the collecting plate to the nozzle diameter d
in
shall be between
0,5uusd/ 5,0 (2)
in
b) Ratio of nozzle length to nozzle diameter
The ratio of the impactor nozzle length l to the nozzle diameter d shall be between
in in
0,25uuld/ 2,0 (3)
in in
This leads to a uniform flow profile at the nozzle outlet, i.e. the flow has a uniform velocity at the nozzle
outlet. If the ratio is too small ( l /d < 0,25), the flow is still non-uniform. If the ratio is too large
in in
( l /d > 2,0), the velocity at the nozzle edge is smaller than the velocity at the centre of the nozzle due to
in in
friction.
c) Reynolds number
The Reynolds number Re of the gas flow in the nozzle shall be in the region of laminar flow
(100 < Re < 3 000).
5.3 Cut-off diameter
In reality, the particle separation is not ideal. In practice, impactors exhibit separation curves similar to the
example shown in Figure 2.
Key
1 ideal
2 real
Figure 2 — Separation efficiency A of an impactor as a function of the cut-off diameter d
50
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
5.4 Cascade impactor
This International Standard specifies a two-stage cascade impactor for the determination of PM and PM
10 2,5
mass concentrations (see Reference [9] in the Bibliography).
NOTE A cascade impactor consists of several impactor stages. The first impactor stage separates the greatest
particles on a collecting plate; smaller particles reach the following stages.
The separation curves of PM and PM emission measurements shall correspond to the separation curves
10 2,5
specified for PM and PM ambient air quality measurements. During sampling, the particles are divided
10 2,5
into three fractions, with aerodynamic diameters greater than 10 µm, between 10 µm and 2,5 µm, and smaller
than 2,5 µm. Therefore, the measurement method allows the simultaneous determination of emission
concentrations of PM and PM .
10 2,5
6 Specification of the two-stage impactor
6.1 General
The two-stage impactor for the determination of PM and PM concentrations in flue gas described in this
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International Standard divides the particles into the following three fractions:
a) particles with aerodynamic diameters greater than 10 µm (first impactor stage);
b) particles with aerodynamic diameters between 10 µm and 2,5 µm (second impactor stage);
c) particles with aerodynamic diameters smaller than 2,5 µm (backup filter).
The PM mass corresponds to fraction c), and the PM mass corresponds to the sum of fractions b) and c).
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The fraction with aerodynamic diameters greater than 10 µm is not used for the PM and PM data
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evaluation.
6.2 Separation curves
The impactor stages for PM and PM shall be designed such that the separation curves of PM and
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PM meet the requirements of the separation efficiencies specified in Tables 1 and 2. The permissible
2,5
deviations specified in Tables 1 and 2 are absolute percentages concerning the separation efficiencies
specified in ISO 7708:1995 (see Figure 3) for the corresponding particle diameters. Furthermore, the
requirements of 5.2 shall be fulfilled.
NOTE The shape of the separation curves can differ from the curves shown in Figure 3 due to experimental
influences (e.g. detailed design of the impactor and gas flow conditions).
Table 1 — Separation efficiency for the PM impactor stage
2,5
Particle Separation efficiency for mono-disperse latex Separation efficiency for mono-disperse latex
diameter aerosol and greased collecting plates aerosol and quartz-fibre filters
1,0 µm Separation efficiency of ISO 7708:1995 at the Separation efficiency of ISO 7708:1995 at the
to corresponding particle diameter with a permissible corresponding particle diameter with a permissible
a
deviation of ±10 % deviation of ±10 %
2,5 µm
> 2,5 µm Separation efficiency of ISO 7708:1995 at the Separation efficiency of ISO 7708:1995 at the
corresponding particle diameter with a permissible corresponding particle diameter with a permissible
to
a
deviation of ±15 % deviation of ±30 %
10,0 µm
a
Approximate diameters.
8 © ISO 2009 – All rights reserved
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SIST EN ISO 23210:2010
ISO 23210:2009(E)
Table 2 — Separation efficiency for the PM impactor stage
10
Particle Separation efficiency for mono-disperse latex Separation efficiency for mono-disperse latex
diameter aerosol and greased collecting plates aerosol and quartz-fibre filters
2,0 µm, Separation efficiency of ISO 7708:1955 at the Separation efficiency of ISO 7708:1995 at the
to corresponding particle diameter with a permissible corresponding particle diameter with a permissible
a
10,0 µm deviation of ±10 % deviation of ±10 %
>10,0 µm Separation efficiency of ISO 7708:1995 at the Separation efficiency of ISO 7708:1995
...
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