SIST EN 60746-3:2004

SLOVENSKI SIST EN 60746-3:2004

STANDARD
marec 2004
Expression of performance of electrochemical analyzers - Part 3: Electrolytic
conductivity
ICS 71.040.40 Referenčna številka
SIST EN 60746-3:2004(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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EUROPEAN STANDARD EN 60746-3
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2002
ICS 17.020; 71.040
English version
Expression of performance of electrochemical analyzers
Part 3: Electrolytic conductivity
(IEC 60746-3:2002)
Expression des qualités Angabe zum Betriebsverhalten
de fonctionnement von elektrochemischen Analysatoren
des analyseurs électrochimiques Teil 3: Elektrolytische Leitfähigkeit
Partie 3: Conductivité électrolytique (IEC 60746-3:2002)
(CEI 60746-3:2002)
This European Standard was approved by CENELEC on 2002-09-01. CENELEC 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 CENELEC 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 CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60746-3:2002 E

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EN 60746-3:2002 - 2 -
Foreword
The text of document 65D/85/FDIS, future edition 2 of IEC 60746-3, prepared by SC 65D, Analyzing
equipment, of IEC TC 65, Industrial-process measurement and control, was submitted to the
IEC-CENELEC parallel vote and was approved by CENELEC as EN 60746-3 on 2002-09-01.
1)
This publication shall be used in conjunction with IEC 60746-1 .
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2003-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-09-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annexes C and ZA are normative and annexes A, B and D are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60746-3:2002 was approved by CENELEC as a European
Standard without any modification.
__________

1)
At draft stage.

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- 3 - EN 60746-3:2002
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1)
IEC 60746-1 - Expression of performance of --
electrochemical analyzers
Part 1: General

1)
Undated reference.

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INTERNATIONAL IEC
STANDARD 60746-3
Second edition
2002-06
Expression of performance of
electrochemical analyzers –
Part 3:
Electrolytic conductivity
Expression des qualités de fonctionnement
des analyseurs électrochimiques –
Partie 3:
Conductivité électrolytique
© IEC 2002 ⎯ Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch  Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale Q
International Electrotechnical Commission
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For price, see current catalogue

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– 2 – 60746-3 © IEC:2002(E)
CONTENTS
FOREWORD.3
1 Scope.5
2 Normative references .5
3 Definitions .5
4 Procedure for specification .8
4.1 Additional statements on sensor units .8
4.2 Additional statements on electronic units.8
4.3 Additional statements on complete analyzers .8
5 Recommended standard values and ranges of influence quantities affecting the
performance of electronic units.8
6 Verification of values .8
6.1 General aspects .9
6.2 Calibration.9
6.3 Test solutions.9
6.4 Test procedures .10
Annex A (informative) Electrolytic conductivity values of potassium chloride calibration
solutions and pure water.12
Annex B (informative) Electrolytic conductivity values of aqueous sodium chloride
solutions .13
Annex C (normative) Alternative procedures for measuring response times: delay
(T ), rise (fall) (T , T ) and 90 % (T ) times .15
10 r f 90
Annex D (informative) Conductivity cells .16
Bibliography.17
Table A.1 – Electrolytic conductivity values.12
Table A.2 – Electrolytic conductivity of pure water .12
Table B.1 – Conductivity of sodium chloride solutions at 18 °C .13
Table B.2 – Temperature coefficients for low-concentration sodium chloride solutions .14
Table B.3 – Tentative corrections to sodium chloride solution temperature coefficients.14

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60746-3 © IEC:2002(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPRESSION OF PERFORMANCE
OF ELECTROCHEMICAL ANALYZERS –
Part 3: Electrolytic conductivity
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60746-3 has been prepared by subcommittee 65D: Analyzing
equipment, of IEC technical committee 65: Industrial-process measurement and control.
This second edition cancels and replaces the first edition, published in 1985, and constitutes
a technical revision.
This standard shall be used in conjunction with IEC 60746-1.
The text of this standard is based on the following documents:
FDIS Report on voting
65D/85/FDIS 65D/87/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
Annex C forms an integral part of this standard.
Annexes A, B and D are for information only.

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– 4 – 60746-3 ¤ IEC:2002(E)
IEC 60746 consists of the following parts, under the general title Expression of performance
of electrochemical analyzers:
Part 1: General
Part 2: pH value
Part 3: Electrolytic conductivity
Part 4: Dissolved oxygen in water measured by membrane covered amperometric sensors
Part 5: Oxidation-reduction potential or redox potential
1)
Part 6: Conductivity effect of foreign ions in ultrapure waters, from combined conductivity and pH
The committee has decided that the contents of this publication will remain unchanged until
2007. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
The contents of the corrigendum of January 2003 have been included in this copy.
________
1)
 Under consideration.

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60746-3 ¤ IEC:2002(E) – 5 –
EXPRESSION OF PERFORMANCE
OF ELECTROCHEMICAL ANALYZERS –
Part 3: Electrolytic conductivity
1 Scope
This part of IEC 60746 is intended
– to specify terminology, definitions and requirements for statements by manufacturers for
analyzers, sensor units, and electronic units used for the determination of the electrolytic
conductivity of aqueous solutions;
– to establish performance tests for such analyzers, sensor units and electronic units;
– to provide basic documents to support the applications of quality assurance standards.
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.
IEC 60746-1, Expression of performance of electrochemical analyzers – Part 1: General
3 Definitions
For the purpose of this part of IEC 60746, the definitions of IEC 60746-1 apply, together with
the following definitions.
3.1
electrolytic conductance
current divided by the potential difference in the case of ionic charge transport within an
electrolytic solution filling a conductivity cell:
I
G =
U
where
I is the current through the electrolyte, in amperes (A);
U is the potential difference applied across the electrodes, in volts (V);
G is the electrolytic conductance, in siemens (S).
Electrolytic resistance is the reciprocal of electrolytic conductance with the ohm (Ω) as the
unit of measurement

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– 6 – 60746-3 ¤ IEC:2002(E)
3.2
electrolytic conductivity
formerly called specific conductance, is defined by the equation:
j
κ =
E
where
–2
j is the electric current density, in A⋅m ;
–1
E is the electric field strength, in V⋅m .
–1
The unit of electrolytic conductivity, κ, is siemens per metre (S⋅m ). Electrolytic resistivity is
the reciprocal of electrolytic conductivity with the unit of ohmmeter (Ω⋅m)
–1
NOTE In practical use, the most commonly employed conductivity unit is microsiemens per centimetre (µS⋅cm )
.
or the corresponding resistivity unit, megohm per centimetre (MΩ cm)
–1 –4 –1
1 µS⋅cm = 10 S⋅m = 1 MΩ⋅cm.
3.3
cell constant of the sensor unit
an electrolytic conductor of a uniform cross-section X and length L is defined by the equation:
L
κ =
cell
X
–1
where K is the cell constant, in m (see Note 1).
cell
It is usual to measure electrolytic conductivity by means of cells without a uniform cross-
section, in which case the K should be determined by means of a reference solution of
cell
known electrolytic conductivity.
The relationship between electrolytic conductance and electrolytic conductivity is defined by
the equation:
κ = K × G
cell
where
–1
κ is the electrolytic conductivity, in S⋅m ;
G is the electrolytic conductance, in S;
–1
K is the cell constant, in m .
cell
–1 –1
NOTE 1 In practical use, K is generally expressed in cm , κ in µS⋅cm and G in µS (see 3.2).
cell
NOTE 2 The cell constant will normally have a constant value over a stated range (see 4.1). Outside this range, it
should be expected that polarization or other effects will produce errors (see 3.4 and annex D).
3.4
polarization
effect which occurs at electrode surfaces in an electrolytic solution when the current between
the electrodes is such as to produce electrolysis and consequent partial insulation of the
electrode surface
To avoid this uncertainty, different measuring methods can be applied (see 3.7, 3.8 and
annex D):
a) a.c. measurements with a frequency high enough to avoid polarization effects;
b) four or six electrode measurements with separated current transporting and potential
measuring electrodes;
c) inductive or capacitive measurements by coupling between the electrolytic conductor and
the electrical measuring circuit through non-conductive media.

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60746-3 ¤ IEC:2002(E) – 7 –
In each case, the relationship between the electrolytic conductivity and the measured output
quantity is established by the cell constant.
3.5
temperature coefficient
relative increase (or decrease) of the electrolytic conductivity of a solution per kelvin
temperature change. The temperature coefficient is dependent on the reference temperature
and the nature of the solution.
The following approximate equation can be applied for strong electrolyte solutions where
–4 –1 –1
κ > 10 S⋅m (1 µS⋅cm )
κ = κ ×()1 + α∆t
t tr
where
κ is the electrolytic conductivity at temperature t;
t
κ is the electrolytic conductivity at reference temperature tr;
tr
∆t is the temperature difference t −tr;
α is the temperature coefficient.
In practice, this formula is sufficiently accurate over a small temperature range. For large
temperature ranges, it is usually necessary to add higher terms of a polynomial series (such
2 3
as β(∆t) + γ(∆t) +.) to the above equation, to obtain sufficient accuracy. The percentage
temperature coefficient, which is the percentage relative deviation per kelvin from the
reference value κ , is often used so that
tr
α (%) = 100 α
NOTE The manufacturer’s literature should be consulted for details of sample temperature compensation
technique(s) applied.
3.6
simulator
a series of non-inductive resistors (preferably step-variable, e.g., a decade resistance box),
used for the performance tests of conductimetric electronic units, simulating two- and three-
electrode sensors
NOTE The minimum step should preferably be 0,01 R, where R is the reciprocal value of the nominal full range
conductivity value. Analogously, the highest resistance value should correspond to the lower limit of the measuring
range: if the range begins at zero, the resistance value should be at least 10 R for testing at 10 % of the range.
...