SIST EN ISO 9225:2012

Corrosion of metals and alloys - Corrosivity of atmospheres - Measurement of environmental parameters affecting corrosivity of atmospheres (ISO 9225:2012) measurement of environmental parameters affecting indoor corrosivity

ISO 9225:2012 specifies methods for measuring the parameters needed for corrosivity estimation used for classification of the corrosivity of atmospheres in ISO 9223.
ISO 9225:2012 specifies methods for the measurement of environmental parameters for normative corrosivity estimation based on calculated first-year corrosion rates of standard metals, and informative corrosivity estimation based on characterization of the exposure environment.
It does not describe the usual analytical techniques for the measured parameters since this depends on the available analytical techniques used in laboratories. Specific methods for deposition measurement of SO2 and Cl- deposition rates and conversional factors for comparison of different measuring methods are given.

Korrosion von Metallen und Legierungen - Korrosivität von Atmosphären - Messung der die Korrosivität von Atmosphären beeinflussenden Umweltparameter (ISO 9225:2012)

Diese Internationale Norm legt Verfahren zur Messung der Parameter fest, die zur Abschätzung der
Korrosivität benötigt werden, die für die Klassifizierung der Korrosivität von Atmosphären nach ISO 9223
verwendet wird.
Diese Internationale Norm legt Verfahren fest zur Messung von Umweltparametern für
 die normative Abschätzung der Korrosivität auf der Grundlage der Korrosionsgeschwindigkeiten
berechnet nach einem Jahr der Auslagerung von metallischen Standardproben, und
 die informative Abschätzung der Korrosivität auf der Grundlage der Charakterisierung der
Auslagerungsumgebung.
In der vorliegenden Internationalen Norm sind die Analysenverfahren für die gemessenen Parameter nicht
beschrieben, weil das von den in den Laboratorien verfügbaren Analysenverfahren abhängt. Spezielle Verfahren
zur Messung der Ablagerungsgeschwindigkeiten von SO2 und von Cl− sowie die Umrechnungsfaktoren zum
Vergleich verschiedener Messverfahren sind in den Anhängen A, B, C, D, E und F angeführt.
Für Verfahren, welche die Charakterisierung der Auslagerungsorte in der Atmosphäre im Allgemeinen
betreffen, siehe ISO 8565.

Corrosion des métaux et alliages - Corrosivité des atmosphères - Mesurage des paramètres environnementaux affectant la corrosivité des atmosphères (ISO 9225:2012)

L'ISO 9225:2012 spécifie des méthodes pour le mesurage des paramètres nécessaires pour l'estimation de la corrosivité utilisée pour la classification de la corrosivité des atmosphères dans l'ISO 9223.
L'ISO 9225:2012 spécifie des méthodes de mesurage des paramètres environnementaux pour l'estimation normative de la corrosivité basée sur les vitesses de corrosion des métaux de référence, calculées sur la première année, et pour l'estimation informative de la corrosivité basée sur la caractérisation de l'environnement d'exposition.
Elle ne décrit pas les méthodes habituelles d'analyse des paramètres mesurés vu qu'elles dépendent des techniques analytiques disponibles dans les laboratoires. Des méthodes spécifiques pour le mesurage des vitesses de dépôt du dioxyde de soufre et des chlorures ainsi que des facteurs de conversion permettant de comparer différentes méthodes de mesurage sont fournis.

Korozija kovin in zlitin - Korozivnost v atmosferskem okolju - Merjenje okoljskih parametrov, ki vplivajo na korozivnost atmosfer (ISO 9225:2012)

Ta mednarodni standard določa metode za merjenje parametrov, potrebnih za oceno korozivnosti za razvrščanje korozivnosti v atmosferskem okolju v standardu ISO 9223. Ta mednarodni standard določa metode za merjenje okoljskih parametrov za: – normativno oceno korozivnosti na podlagi izračunanih hitrosti korozije standardnih kovin v prvem letu in – informativno oceno korozivnosti na podlagi značilnosti okolja izpostavljenosti. Ta mednarodni standard ne opisuje običajnih analitskih tehnik za izmerjene parametre, ker je to odvisno od razpoložljivih analitskih tehnik, ki se uporabljajo v laboratorijih. Posebne metode za merjenje nalaganja SO2 in Cl – hitrosti nalaganja in pretvorbeni faktorji za primerjavo različnih merilnih metod so predstavljeni v dodatkih A, B, C, D, E in F. Za metode, ki se nanašajo na označevanje območij izpostavljenosti atmosferskemu okolju na splošno, glejte standard ISO 8565.

General Information

• Status: Published
• Publication Date: 11-Apr-2012
• ICS: 77.060 - Corrosion of metals
• Technical Committee: IPKZ - Protection of metals against corrosion
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 26-Mar-2012
• Due Date: 31-May-2012
• Completion Date: 12-Apr-2012
• Ref Project: EN ISO 9225:2012 - Corrosion of metals and alloys - Corrosivity of atmospheres - Measurement of environmental parameters affecting corrosivity of atmospheres (ISO 9225:2012)

Relations

• Replaces: SIST EN 12500:2000 - Protection of metallic materials against corrosion - Corrosion likelihood in atmospheric environment - Classification, determination and estimation of corrosivity of atmospheric environments
• Effective Date: 01-May-2012
• Replaces: SIST EN 12500:2000 - Protection of metallic materials against corrosion - Corrosion likelihood in atmospheric environment - Classification, determination and estimation of corrosivity of atmospheric environments
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 9225:2012
01-maj-2012
1DGRPHãþD
SIST EN 12500:2000
Korozija kovin in zlitin - Korozivnost v atmosferskem okolju - Merjenje okoljskih
parametrov, ki vplivajo na korozivnost atmosfer (ISO 9225:2012)
&RUURVLRQRIPHWDOVDQGDOOR\V&RUURVLYLW\RIDWPRVSKHUHV0HDVXUHPHQWRI
HQYLURQPHQWDOSDUDPHWHUVDIIHFWLQJFRUURVLYLW\RIDWPRVSKHUHV,62
PHDVXUHPHQWRIHQYLURQPHQWDOSDUDPHWHUVDIIHFWLQJLQGRRUFRUURVLYLW\
Korrosion von Metallen und Legierungen - Korrosivität von Atmosphären - Messung der
die Korrosivität von Atmosphären beeinflussenden Umweltparameter (ISO 9225:2012)
Corrosion des métaux et alliages - Corrosivité des atmosphères - Mesurage des
paramètres environnementaux affectant la corrosivité des atmosphères (ISO 9225:2012)
Ta slovenski standard je istoveten z: EN ISO 9225:2012
ICS:
77.060 Korozija kovin Corrosion of metals
SIST EN ISO 9225:2012 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9225:2012

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SIST EN ISO 9225:2012


EUROPEAN STANDARD
EN ISO 9225

NORME EUROPÉENNE

EUROPÄISCHE NORM
February 2012
ICS 77.060 Supersedes EN 12500:2000
English Version
Corrosion of metals and alloys - Corrosivity of atmospheres -
Measurement of environmental parameters affecting corrosivity
of atmospheres (ISO 9225:2012)
Corrosion des métaux et alliages - Corrosivité des Korrosion von Metallen und Legierungen - Korrosivität von
atmosphères - Mesurage des paramètres Atmosphären - Messung der die Korrosivität von
environnementaux affectant la corrosivité des atmosphères Atmosphären beeinflussenden Umweltparameter (ISO
(ISO 9225:2012) 9225:2012)
This European Standard was approved by CEN on 22 January 2012.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9225:2012: E
worldwide for CEN national Members.

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SIST EN ISO 9225:2012
EN ISO 9225:2012 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 9225:2012
EN ISO 9225:2012 (E)
Foreword
This document (EN ISO 9225:2012) has been prepared by Technical Committee ISO/TC 156 "Corrosion of
metals and alloys" in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic
coatings” the secretariat of which is held by BSI.
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 August 2012, and conflicting national standards shall be withdrawn at
the latest by August 2012.
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.
This document supersedes EN 12500:2000.
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, Croatia, 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, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 9225:2012 has been approved by CEN as a EN ISO 9225:2012 without any modification.

3

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SIST EN ISO 9225:2012

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SIST EN ISO 9225:2012

INTERNATIONAL ISO
STANDARD 9225
Second edition
2012-02-01

Corrosion of metals and alloys —
Corrosivity of atmospheres —
Measurement of environmental
parameters affecting corrosivity of
atmospheres
Corrosion des métaux et alliages — Corrosivité des atmosphères —
Mesurage des paramètres environnementaux affectant la corrosivité
des atmosphères




Reference number
ISO 9225:2012(E)
©
ISO 2012

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SIST EN ISO 9225:2012
ISO 9225:2012(E)

COPYRIGHT PROTECTED DOCUMENT


©  ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO 2012 – All rights reserved

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SIST EN ISO 9225:2012
ISO 9225:2012(E)
Contents Page
Foreword . iv
Introduction . v
1  Scope . 1
2  Normative references . 1
3  Principle . 1
4  Humidity and temperature parameters . 2
4.1  Relative humidity . 2
4.2  Temperature . 2
5  Airborne contaminants . 2
5.1  Principle . 2
5.2  Placement of measurement equipment . 3
5.3  Measurement methods and duration . 3
Annex A (normative) Determination of sulfur dioxide deposition rate on lead dioxide sulfation
plates . 6
Annex B (normative) Determination of sulfur dioxide deposition rate on lead dioxide sulfation
cylinder . 9
Annex C (normative) Determination of sulfur dioxide deposition rate on alkaline surfaces . 12
Annex D (normative) Determination of chloride deposition rate by the wet candle method . 14
Annex E (normative) Determination of chloride deposition rate by dry plate method . 18
Annex F (normative) Comparison of chlorides and sulfur dioxide deposition rates determined by
different methods . 21
Bibliography . 22

© ISO 2012 – All rights reserved iii

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SIST EN ISO 9225:2012
ISO 9225:2012(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 9225 was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys.
This second edition cancels and replaces the first edition (ISO 9225:1992), which has been technically revised.
iv © ISO 2012 – All rights reserved

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SIST EN ISO 9225:2012
ISO 9225:2012(E)
Introduction
The ability of an atmosphere to cause corrosion of metals and alloys is controlled by the following factors: the
temperature-humidity complex and pollution. A basic requirement for the estimation of the corrosivity of
atmospheres is standardized measurement of the important parameters describing the correlation between
the corrosion and the environmental characteristics.
The methods included in this International Standard have been chosen for their easy applicability and good
comparability of results. It is important to stress that the methods for estimation of the atmospheric corrosivity
given in ISO 9223 are based on the measurement methods described in this International Standard.

© ISO 2012 – All rights reserved v

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SIST EN ISO 9225:2012

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SIST EN ISO 9225:2012
INTERNATIONAL STANDARD ISO 9225:2012(E)

Corrosion of metals and alloys — Corrosivity of atmospheres —
Measurement of environmental parameters affecting corrosivity
of atmospheres
WARNING — Some of the procedures included in this International Standard entail the use of
potentially hazardous chemicals. lt is emphasized that all appropriate safety precautions should be
taken.
1 Scope
This International Standard specifies methods for measuring the parameters needed for corrosivity estimation
used for classification of the corrosivity of atmospheres in ISO 9223.
This International Standard specifies methods for the measurement of environmental parameters for
 normative corrosivity estimation based on calculated first-year corrosion rates of standard metals, and
 informative corrosivity estimation based on characterization of the exposure environment.
This International Standard does not describe the usual analytical techniques for the measured parameters
since this depends on the available analytical techniques used in laboratories. Specific methods for deposition

measurement of SO and Cl deposition rates and conversional factors for comparison of different measuring
2
methods are presented in Annexes A, B, C, D, E and F.
For methods pertaining to the characterization of the atmospheric exposure site in general, see ISO 8565.
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 9223, Corrosion of metals and alloys — Corrosivity of atmospheres — Classification, determination and
estimation
ISO 11844-3, Corrosion of metals and alloys — Classification of low corrosivity of indoor atmospheres —
Part 3: Measurement of environmental parameters affecting indoor corrosivity
3 Principle
Different environmental parameters and their combinations affect the corrosivity of the atmosphere. Two
methods for corrosivity estimation (normative and informative) are specified in ISO 9223.
In general, two groups of parameters are obtained or measured for standardized procedures of corrosivity
estimation:
 humidity and temperature;
 airborne contaminants.
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SIST EN ISO 9225:2012
ISO 9225:2012(E)
Standardized corrosivity estimation is based on information on levels of the dominating environmental
parameters: the temperature-humidity complex, and pollution with SO and airborne chlorides. Measurements
2
of these parameters are mandatory for the purpose of corrosivity estimation.

Contaminants other than SO and Cl , such as NO , O , H S, HNO , can also exert an effect on the
2 x 3 2 3
2  
corrosion rate. Corrosion active components of dust deposits (SO , NO , Cl ) react with metals in the
4 3
presence of humidity. These factors are considered as accompanying factors (see ISO 9223). These
environmental parameters, which contribute to the effect on corrosion of standard metals in multi-pollutant
situations, are not included as mandatory parameters for corrosivity estimation in ISO 9223. Information on
levels of these parameters can help in informative corrosivity estimation.
Methods for the measurement of environmental parameters to be used specifically for the estimation of low
corrosivity of indoor atmospheres (IC) are given in ISO 11844-3.
4 Humidity and temperature parameters
4.1 Relative humidity
Reliable long-term average values for relative humidity can often be obtained from the meteorological
authorities in the country. Several types of measuring devices can be used if collection of new data for the
locality is needed. There are several continuous measuring devices, such as hygrographs,
thermohygrographs or logging hygrometers, available on the market.
The period of measurement is preferably one year in order to cover seasonal variations and because the
classification system is based on yearly average values. The data shall be expressed as yearly mean values.
4.2 Temperature
Reliable long-term average values for temperature can often be obtained from the meteorological authorities
in the country. Several types of measuring devices can be used if collection of new data for the locality is
needed. There are several continuous measuring devices, such as thermohygrographs or logging
thermometers, available on the market.
The period of measurement is preferably one year in order to cover seasonal variations and because the
classification system is based on yearly average values. The data shall be expressed as yearly mean values.
5 Airborne contaminants
5.1 Principle
The gas concentration or deposition rate may be measured using several techniques:
 continuous gas concentration measuring instruments;
 average gas concentration with active sampler and air pump;
 average gas concentration with diffusive (passive) sampler;
 average deposition rate equipment.
3
The results from concentration measurements are typically given in micrograms per cubic metre (µg/m ) and,
2
for deposition measurements, in milligrams per square metre per day [mg/(md)].
2 © ISO 2012 – All rights reserved

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SIST EN ISO 9225:2012
ISO 9225:2012(E)
5.2 Placement of measurement equipment
5.2.1 Continuous gas concentration measurement instruments
The instrument shall be located in a place that is sheltered from the rain and protected from unauthorized
people. Preferably, the instrument should be placed indoors with a tube leading out to the ambient air.
Polyethylene or PTFE tubing is recommended and the length of the tubing should not exceed 2 m. The inlet
shall be facing down with a wider hood at the inlet to reduce the risk of sucking particulates into the tube.
5.2.2 Measurement instruments with active sampler
The active sampler equipment shall be placed according to the same rules as the continuous gas-measuring
instrument.
5.2.3 Measurement instruments with diffusive sampler
The sampling device shall be placed with the open end facing downward under appropriate shelter. The air
flow influences the gas diffusion in the sampler.
5.2.4 Deposition rate equipment
The equipment shall be sheltered from setting particles and from washing out by rain for outdoor deposition
measurements. The air flow influences the deposition rate.
5.3 Measurement methods and duration
5.3.1 Continuous measurement
The measurements shall preferably be carried out for one year in order to record the seasonal variation of the
gas pollutants. The data from continuous measuring instruments shall be recorded as monthly average values.
For the corrosivity estimation, the data shall be expressed as yearly mean values.
5 6
Standard instruments have detection limits in a range from 4  10 volume fractions to 1  10 volume
fractions.
5.3.2 Measurement with active sampler
The methods are based on pumping air through an absorption unit with a reactive surface or liquid, with
subsequent laboratory analysis of the amount absorbed. The sampling period shall be one week. The data
shall be collected over the sampling periods and summarized to monthly average values. The result is given
as an average concentration for the measuring period.
The measuring period is preferably one year or at least one month for each season of the year. For the
corrosivity estimation, the data shall be expressed as yearly mean values.
NOTE The detection limits for air concentrations depend on the sensitivity of the analysing instruments and the
duration of the sampling. For an analytical instrument with normal sensitivity, it is possible to obtain weekly average values
3
with a detection limit better than 0,1 µg/m .
5.3.3 Measurement with diffusive sampler
Mean gas concentrations can be calculated using diffusive sampling devices. The principle used for diffusive
sampling is shown in Figure 1. The recommended sampling period is one month, but can be extended to three
months, corresponding to one measurement for each season of the year. The measurement period is
preferably one year.
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SIST EN ISO 9225:2012
ISO 9225:2012(E)

Key
1 absorbent
2 tube
3 permeable screen for gases
C ambient concentration of gas
1
C concentration of gas at the absorbent equal zero
0
Figure 1 — Principle of concentration calculation for a diffusive sampler

3
NOTE Normal sensitivity for weekly mean values is down to 0,1 µg/m for SO , but higher for other gases. Generally
2
the detection limit decreases with increasing sampling time.
The general calculation model is specified in ISO 11844-3.
The data shall be expressed as yearly mean values.
5.3.4 Measurement of deposition rate of pollution
The deposition takes place on an absorbing or collecting surface similar to the surfaces used for diffusive
sampling devices. In the deposition method standardized for SO deposition measurements, the gas reacts
2
when it reaches the lead dioxide surface or alkaline surface (see Annexes A, B and C). In the methods
standardized for airborne salinity measurements, particles (aerosol) are deposited on a wet or dry surface
designed to collect this pollutant (see Annexes D and E). Since the collecting system is open, the deposition
rate depends on the movement of the air.
NOTE The use of lead compounds can be restricted in some countries.
SO deposition measurements performed by the lead dioxide plates and by the lead dioxide cylinder differ
2
with regard to the kind and shape of the deposition surface. Both measurements give values with low
correlation for monthly sampling periods due to the greater variation in weather characteristics. A high
correlation exists for annual average values (see Annex F). Capture of sulfuric acid aerosols and
sulfur-bearing species from precipitation and sea salt deposition can occur.
The SO deposition values used for the derivation of the dose-response functions given in ISO 9223 are either
2
based on deposition measurements on alkaline surfaces or converted values based on concentration
measurements.
Chloride deposition rates determined by the dry plate method and by the wet candle method differ because
the kind and shape of deposition surface are different (wet/dry surfaces, cylindrical/plate format of the
deposition surface). There is little difference in the deposition rates determined by the two methods at
2
locations with very low deposition rates, i.e. 10 mg/(md). On the other hand, at higher chloride deposition
rates, the wet candle method gives deposition rates that are approximately twice as high as those given by the
dry plate method. Both these measurements give values with low correlation for monthly sampling periods due
to the great variation in weather characteristics. A high correlation exists for annual average values (see
Annex F).
4 © ISO 2012 – All rights reserved

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SIST EN ISO 9225:2012
ISO 9225:2012(E)
The chloride deposition values used for the derivation of the dose-response functions given in ISO 9223 are
based on measurements with the wet candle method. If the chloride deposition is measured with the dry plate
method (see Annex E), it is necessary that the transformation factor given in Annex F be applied before using
the dose-response functions.
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SIST EN ISO 9225:2012
ISO 9225:2012(E)
Annex A
(normative)

Determination of sulfur dioxide deposition rate
on lead dioxide sulfation plates
A.1 Principle
Atmospheric sulfur dioxide (SO ) reacts with the lead dioxide (PbO ) to form lead sulfate (PbSO ). The plates
2 2 4
are withdrawn after exposure and sulfate analysis is performed on the contents to determine the extent of
sulfur dioxide capture. The deposition rate of sulfur dioxide is expressed in milligrams per square metre per
2
day [mg/(md)].
The lead dioxide reagent used in this method can also convert other sulfur-bearing compounds, such as
hydrogen sulfide (H S) and mercaptans (C H SH), to sulfate.
2 2 5
The inverted position of the disc is intended to minimize sulfur capture from acid precipitation or sulfuric
acid (H SO ) aerosols.
2 4
A.2 Sampling apparatus
A.2.1 Sulfation plate
Sulfation plates may be purchased ready for exposure or may be prepared. The following method is
recommended for the preparation of sulfation plates.
Bond filter paper circles to the bottom of polystyrene Petri dishes. The circle diameters may be 50 mm or
60 mm. Bonding is carried out by placing a filter paper rough side up, in the bottom of the dish. The filter paper
should fit inside the dish without wrinkling. Carefully squirt acetone into the dish so that the filter becomes just
saturated. Press the filter paper firmly with a glass rod so that it adheres completely to the dish. Allow the
acetone to evaporate.
Place a batch of bonded plates (several tens of either 50 mm plates or 60 mm plates) in a rack and rinse with
distilled or demineralized water. Fill the plates with water again and allow to stand for 1 h. Pour the water out
of the plates and refill to between one quarter and one half with distilled or deionized water.
Add 3,5 g of tragacanth gum and 900 ml of distilled or deionized water to a high-speed blender. Set at a low
speed and blend for 2 h.
Pour the contents of the blender into a 1 l beaker and pour 350 ml of the solution back into the blender. Pulp
3,5 g of filter paper, add them to the 350 ml of gum solution and set the blender at a moderate speed until the
mixture appears smooth and uniform.
Pour 400 ml of the previously prepared gum solution into the blender and blend at a moderate speed for
1 min.
Set the blender at a high speed and add 112 g of lead dioxide. Blend for 2 min and then turn the blender back
to a low speed.
Carefully pipette 10 ml of the mixture into each 50 mm plate or 15 ml into each 60 mm plate. Make sure that
the mixture spreads uniformly to the edge of each plate.
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SIST EN ISO 9225:2012
ISO 9225:2012(E)
Place the rack of plates in an oven set at 40 °C to 50 °C for 20 h.
Remove the plates from the oven, allow to cool and seal them with tight-fitting covers to protect them until
exposure begins.
Number the plates and expose them within 120 days of preparation. Retain at least three plates from each
batch for reference.
A.2.2 Exposure rack
Brackets shall be used to hold the plates securely in an inverted position so that the lead dioxide mixture faces
downwards. The plates shall be horizontal and shall not be obstructed from normal winds and air circulation
currents. The brackets shall be constructed from a material which has adequate resistance to atmospheric
corrosion. They shall include a retaining clip or other provision to hold the plate in the event of strong winds. A
typical bracket design is shown in Figure A.1.
Dimensions in millimetres

Key
1 retainer
2 plastic Petri dish  60
3 lead dioxide (PbO ) paste
2
4 bracket
Figure A.1 — Sulfation plate holder
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SIST EN ISO 9225:2012
ISO 9225:2012(E)
A.3 Sampling
When monitoring exposure sites, a minimum of three plates shall be used for each sampling period.
The plates should be placed, if possible, at the highest and lowest levels of exposure of corrosion test
specimens.
A (30  2) day sampling period is recommended. At the end of the sampling period, the plates should be
removed from the bracket and covered tightly to prevent additional sulfation. Analysis of the plates should be
performed within 60 days of completing exposure. When the exposure is finished, the plate identification,
exposure location and the dates of exposure initiation and completion shall be recorded.
A.4 Sulfate analysis
The contents of the sulfation plate are removed and dissolved, for example using a solution of sodium
carbonate. Thereafter, conventional sulfate analysis may be employed, for example turbidimetrical or
spectrophotometric methods.
A.5 Expression of results
The sulfation rate is calculated in terms of sulfur dioxide (SO ) captured by the plate. The mass of SO
2 2
obtained from the plate analysis procedure is converted to net SO mass by subtracting the blank value
2
obtained from the batch of plates in question.
2
The deposition rate of sulfur dioxide (SO ), expressed in milligrams per square metre per day [mg/(md)],
2
P , is given by Equation (A.1):
d,p
mm
10
(A.1)
P 
d,p
A·t
where
m is the total mass, in milligrams, of sulfur dioxide in the exposed plate;
1
m is the total mass, in milligrams, of sulfur dioxide in the non-exposed plate;
0
2
A is the area, in square metres, of the exposed part of the test plate (i.e. 0,03 m );
t is the exposure time, in days.

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SIST EN ISO 9225:2012
ISO 9225:2012(E)
Annex B
(normative)

Determination of sulfur dioxide deposition rate
on lead dioxide sulfation cylinder
B.1 Principle
Atmospheric sulfur dioxide (SO ) reacts with lead dioxide (PbO ) to form lead sulfate (PbSO ). The cylinders
2 2 4
are withdrawn after exposure and sulfate analysis is performed on the contents to determine the extent of
sulfur dioxide c
...