EN 60554-2:2002

SLOVENSKI SIST EN 60554-2:2004

STANDARD
september 2004
Celulozni papir za elektrotehnične namene - 2. del: Preskusne metode (IEC
60554-2:2001)
Cellulosic papers for electrical purposes - Part 2: Methods of test (IEC 60554-
2:2001)
ICS 29.035.10 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 60554-2
NORME EUROPÉENNE
EUROPÄISCHE NORM April 2002
ICS 17.220.99;29.035.10
English version
Cellulosic papers for electrical purposes
Part 2: Methods of test
(IEC 60554-2:2001)
Papiers cellulosiques Zellulosepapiere für elektrotechnische
à usages électriques Zwecke
Partie 2: Méthodes d'essai Teil 2: Prüfverfahren
(CEI 60554-2:2001) (IEC 60554-2:2001)
This European Standard was approved by CENELEC on 2002-04-01. 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, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, 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 60554-2:2002 E
Foreword
The text of document 15C/1264/FDIS, future edition 2 of IEC 60554-2, prepared by SC 15C,
Specifications, of IEC TC 15, Insulating materials, was submitted to the IEC-CENELEC parallel vote
and was approved by CENELEC as EN 60554-2 on 2002-04-01.
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) 2003-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2005-04-01
Annexes designated "normative" are part of the body of the standard.
In this standard, annex ZA is normative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60554-2:2001 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 60554-2:2002
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
IEC 60216 Series Electrical insulating materials - HD 611 Series
Properties of thermal endurance EN 60216 Series
1) 2)
IEC 60243-1 - Electrical strength of insulating EN 60243-1 1998
materials - Test methods
Part 1: Tests at power frequencies
IEC 60247 1978 Measurement of relative permittivity,--
dielectric dissipation factor and d.c.
resistivity of insulating liquids
IEC 60250 1969 Recommended methods for the --
determination of the permittivity and
dielectric dissipation factor of electrical
insulating materials at power, audio and
radio frequencies including metre
wavelengths
IEC 60296 1982 Specification for unused mineral --
insulating oils for transformers and
switchgear
IEC 60450 1974 Measurement of the average --
viscometric degree of polymerization of
new and aged electrical papers
IEC 60554-3 Series Specification for cellulosic papers for--
electrical purposes
Part 3: Specifications for individual
materials
ISO 287 1985 Paper and board - Determination of EN 20287 1994
moisture content - Oven-drying method

1)
Undated reference.
2)
Valid edition at date of issue.

Publication Year Title EN/HD Year
ISO 534 1988 Paper and board - Determination of EN 20534 1993
thickness and apparent bulk density or
apparent sheet density
ISO 535 1991 Paper and board - Determination of EN 20535 1994
water absorptiveness - Cobb method
ISO 536 1995 Paper and board EN ISO 536 1996
Determination of grammage
ISO 1924-1 1992 Paper and board - Determination of--
tensile properties
Part 1: Rate of loading method
ISO 1924-2 1994 Part 2: Constant rate of elongation EN ISO 1924-2 1995
method
ISO 1974 1990 Paper - Determination of tearing EN 21974 1994
resistance (Elmendorf method)
ISO 2144 1997 Paper, board and pulps - Determination--
of residue (ash) on ignition at 900
degrees C
ISO 2758 1983 Paper - Determination of bursting--
strength
ISO 9964-3 1993 Water quality - Determination of sodium--
and potassium
Part 3: Determination of sodium anf
potassium by flame emission
spectrometry
NORME CEI
INTERNATIONALE IEC
60554-2
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
2001-11
Papiers cellulosiques à usages électriques –
Partie 2:
Méthodes d'essai
Cellulosic papers for electrical purposes –
Part 2:
Methods of test
 IEC 2001 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http://www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
V
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

60554-2  IEC:2001 – 3 –
CONTENTS
FOREWORD.9
INTRODUCTION.11
1 Scope.13
2 Normative references.13
3 Definitions .15
4 General notes on tests.15
5 Thickness .17
5.1 Determination of the thickness of single sheets of paper (ISO 534) .17
5.2 Determination of mean thickness of paper .17
6 Substance (mass per square metre, basic weight or grammage) .17
7 Apparent density.19
8 Tensile strength and elongation .19
9 Internal tearing resistance.19
10 Edge-tearing resistance .21
10.1 Test apparatus .21
10.2 Test pieces.21
10.3 Procedure.21
10.4 Results.23
11 Bursting strength .23
12 Folding endurance .23
12.1 Test apparatus .23
12.2 Test pieces.23
12.3 Procedure.23
12.4 Results.23
13 Moisture content .23
14 Ash content .25
15 Conductivity of aqueous extract .25
15.1 Test apparatus .25
15.2 Procedure.25
15.3 Results.27
16 pH of aqueous extract.27
16.1 Test apparatus .27
16.2 Procedure.27
16.3 Results.27
17 Chloride content of aqueous extract .29
17.1 Method 1 .29
17.2 Method 2 .31
18 Sulphate content.33

60554-2  IEC:2001 – 5 –
19 Conductivity of organic extract .33
19.1 Test apparatus .33
19.2 Procedure.35
19.3 Results.35
20 Determination of sodium and potassium content;
flame atomic absorption spectrometric method.37
21 Air permeability.37
21.1 Test apparatus .37
21.2 Test pieces.39
21.3 Procedure.39
21.4 Results.39
22 Rate of water absorption (wicking) .39
22.1 Principle .39
22.2 Reagent .39
22.3 Apparatus.39
22.4 Conditioning .41
22.5 Test pieces.41
22.6 Procedure.41
22.7 Results.43
22.8 Test report.43
23 Oil absorption (modified Cobb method) .43
23.1 Test apparatus .43
23.2 Test pieces.45
23.3 Procedure.45
23.4 Results.45
24 Electric strength.47
24.1 Test apparatus .47
24.2 Test pieces.47
24.3 Procedure.47
24.4 Results.47
24.5 Test method using d.c. voltage .47
25 Dissipation factor and permittivity of unimpregnated paper .51
25.1 Test apparatus .51
25.2 Test pieces.53
25.3 Procedure.53
25.4 Results.55
26 Conducting paths.55
26.1 Method 1 .55
26.2 Method 2 .57
27 Heat stability.61
27.1 Internal tearing resistance.61
27.2 Bursting strength .61
27.3 Degree of polymerization .61

60554-2  IEC:2001 – 7 –
Figure 1 – Edge tear stirrup.63
Figure 2a – Overview .65
Figure 2b – Details (modifications required to Cobb absorbency tester) .65
Figure 2 – Test apparatus for oil absorbency .65
Figure 3 – Diagrammatic arrangement of test apparatus for conducting particles .67
Figure 4 – Test apparatus .67
Figure 5 – Water absorbency apparatus .69

60554-2  IEC:2001 – 9 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CELLULOSIC PAPERS FOR ELECTRICAL PURPOSES –
Part 2: Methods of test
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 60554-2 has been prepared by subcommittee 15C: Specifications,
of IEC technical committee 15: Insulating materials.
This second edition cancels and replaces the first edition published in 1977, amendment 1
(1982), amendment 2 (1984), and amendment 3 (1995) and constitutes a technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
15C/1264/FDIS 15C/1311/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.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next revision.
The committee has decided that the contents of this publication will remain unchanged until 2006.
At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
60554-2  IEC:2001 – 11 –
INTRODUCTION
IEC 60554 consists of the following parts, under the general title: Cellulosic papers for
electrical purposes.
– Part 1: Definition and general requirements
– Part 2: Methods of test
– Part 3: Specifications for individual materials

60554-2  IEC:2001 – 13 –
CELLULOSIC PAPERS FOR ELECTRICAL PURPOSES –
Part 2: Methods of test
1 Scope
This part of IEC 60554 applies to cellulosic papers for electrical purposes. It specifies the
methods of test to be used in testing cellulosic papers for electrical purposes to meet
the requirements prescribed in the specification sheet of IEC 60554-3.
In this standard, reference is made in several places to ISO standards accompanied by a short
description of the method used. It is to be understood that this short description is meant for
identification purposes only and that all details should be taken from the ISO standard itself.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60554. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 60554 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. For undated references,
the latest edition of the normative document referred to applies. Members of IEC and ISO
maintain registers of currently valid International Standards.
IEC 60216: Guide for the determination of thermal endurance properties of electrical insulating
materials
IEC 60243-1: Electric strength of insulating materials – Test methods – Part 1: Tests at power
frequencies
IEC 60247:1978, Measurement of relative permittivity, dielectric dissipation factor and d.c.
resistivity of insulating liquids
IEC 60250:1969, Recommended methods for the determination of the permittivity and dielectric
dissipation factor of electrical insulating materials at power, audio and radio frequencies
including metre wavelengths
IEC 60296:1982, Specification for unused mineral insulating oils for transformers and
switchgear
IEC 60450:1974, Measurement of the average viscometric degree of polymerization of new and
aged electrical papers
IEC 60554-3, Cellulosic papers for electrical purposes – Part 3: Specifications for individual
materials
ISO 287:1985, Paper and board – Determination of moisture content – Oven-drying method
ISO 534:1988, Paper and board – Determination of thickness and apparent bulk density or
apparent sheet density
60554-2  IEC:2001 – 15 –
ISO 535:1991, Paper and board – Determination of water absorptiveness – Cobb method
ISO 536:1995, Paper and board – Determination of grammage
ISO 1924-1:1992, Paper and board – Determination of tensile properties – Part 1: Constant
rate of loading method
ISO 1924-2:1994, Paper and board – Determination of tensile properties – Part 2: Constant
rate of elongation method
ISO 1974:1990, Paper – Determination of tearing resistance (Elmendorf method)
ISO 2144:1997, Paper, board and pulps – Determination of residue (ash) on ignition at
900 degrees C
ISO 2758:1983, Paper – Determination of bursting strength
ISO 9964-3:1993, Water quality – Determination of sodium and potassium – Part 3:
Determination of sodium and potassium by flame emission spectrometry
3 Definitions
For the purpose of this part of IEC 60554, the following definitions apply.
3.1
specimen
rectangle of paper cut to given dimensions from a reel or a sheet drawn from selected units
3.2
test piece
quantity of paper on which each single determination is carried out in accordance with the
method of test. It may be taken from a specimen; in some instances it may be the specimen
itself
4 General notes on tests
Unless otherwise specified, the specimen, after being cut, shall be conditioned for not less than
16 h in an atmosphere of 23 °C ± 2 K and 50 % ± 5 % relative humidity. Test pieces are cut
from the specimen and tested in this atmosphere.
In case of dispute, the conditioning atmosphere shall be 23 °C ± 1 K and 50 % ± 2 % relative
humidity and shall be approached from the dry side (after drying at 70 °C to a moisture content
less than 4 %).
Unless otherwise specified, the number of specimens shall be three.
Unless otherwise specified, the central values of the measurements shall be taken as the result
and the highest and lowest values shall be reported.

60554-2  IEC:2001 – 17 –
5 Thickness
Thickness shall be measured in accordance with ISO 534 with the exceptions given below.
5.1 Determination of the thickness of single sheets of paper (ISO 534)
a) Principle
The method is based on the use of a precision dial micrometer to measure the thickness of
a single sheet when a static load is applied.
The static load to be applied shall correspond to a pressure of 100 kPa ± 10 kPa.
b) Exceptions
The test shall be carried out on three conditioned test pieces, one determination being
made on each of the three test pieces. One determination consists in five measurements,
one at each corner and one in the centre of the test piece.
The results are given in microns.
Where thickness is determined across the width to establish the variation over the width, the
details of this procedure will be found in IEC 60554-3.
5.2 Determination of mean thickness of paper
Principle
The method is based on the use of a precision dial micrometer to measure the thickness of a
stack composed of a minimum of five sheets.
The static load to be applied shall correspond to a pressure of 100 kPa ± 10 kPa.
The test shall be carried out on three conditioned test pieces, each composed of a minimum of
five sheets measuring 250 mm × 250 mm taken from one single specimen, one determination
being made on each of the three test pieces. One determination consists of five
measurements, one at each corner and one in the centre of the test piece.
For narrow material where the width is less than the stipulated 250 mm, the five measurements
on each stack shall be made at approximately equal intervals on a specimen measuring
400 mm in length.
The results are given in terms of the thickness of a single sheet in microns.
Where thickness is determined across the width to establish the variation over the width, the
details of this procedure will be found in IEC 60554-3.
6 Substance (mass per square metre, basic weight or grammage)
Paper grammage shall be measured according to the method described in ISO 536 with the
following exceptions:
– clauses 5 and 6 of ISO 536 are ignored;

60554-2  IEC:2001 – 19 –
– the test shall be carried out on three conditioned test pieces, one determination being made
on each of the three test pieces;
– the mass is to be determined to an accuracy of 0,5 % on conditioned test pieces of not less
than 500 cm .
Principle
The area of each test piece and its mass are measured and the mass per unit expressed in
grams per square metre is calculated, all measurements being made on conditioned test
pieces.
Where grammage is determined across the width to establish the variation over the width, the
details of this procedure will be found in IEC 60554-3.
7 Apparent density
The thickness and grammage are determined on each of three test pieces in accordance with
clauses 5 and 6. For each test piece the apparent density is calculated. The apparent density is
expressed in grams per cubic centimetre.
8 Tensile strength and elongation
Tensile strength and elongation shall be measured according to one of the methods described
in ISO 1924 with the following exceptions (the method to be used shall be indicated in
IEC 60554-3):
– measurements are made on nine test pieces cut from the machine direction and on nine
others cut from the cross direction;
– the central value of the measurements, in each direction, is taken as the result and the
highest and the lowest values in each direction are reported;
– alternatively, the results can be expressed as the breaking length in metres rounded to the
nearest 100 m.
Principle
Measurement of the tensile force required to cause failure of test pieces 15 mm by
approximately 250 mm, cut from both directions of the paper, when applied under standard test
conditions.
9 Internal tearing resistance
Internal tearing resistance shall be measured according to the method described in ISO 1974.
The single-tear tester shall be used with the following exceptions:
– measurements are made on nine test pieces cut from the machine direction and nine others
from the cross direction.
Principle
Rectangular test pieces having a single cut leaving 43 mm length to be torn. Measurement of
the energy required to tear this.

60554-2  IEC:2001 – 21 –
10 Edge-tearing resistance
10.1 Test apparatus
An edge-tear stirrup (see figure 1) shall be used, attached to the tensile testing apparatus as
described in ISO 1924. The edge-tear stirrup consists of a thin steel plate (A) which forms a
vertical plate supported on the edge by the ends of a stirrup-shaped frame.
The thin metal tang of the stirrup frame is fastened in the lower clamp of the tension testing
machine, so that the vertical centre line of the stirrup coincides with the line connecting
the midpoints of the upper and lower clamps. The vertical plate is removable from the stirrup
frame and two plates of different thickness are supplied for use with papers of different
thickness ranges. One plate has a thickness of 1,25 mm ± 0,05 mm and one plate a thickness
of 2,50 mm ± 0,05 mm. The edge of the plate forms a shallow V-notch, the sides of which
subtend an angle of 150° ± 1°. The sides of the V-notch are semicircular in cross-section and
shall be smooth and straight.
10.2 Test pieces
Nine test pieces shall be cut in the machine direction and nine in the cross direction of the
paper, 15 mm to 25 mm in width and not less than 250 mm in length.
The test pieces shall be conditioned according to clause 4.
10.3 Procedure
Attach a plate of the proper thickness to the stirrup frame. The plate with the thickness of
1,25 mm ± 0,05 mm is to be used for papers of up to 0,75 mm in thickness and the plate with
the thickness of 2,50 mm ± 0,05 mm for thicker papers.
Fasten the thin tang of the stirrup in the lower clamp (see note) of the tension-testing machine
so that the vertical centre line of the stirrup coincides with the line connecting the mid-points of
the upper and lower clamps of the testing machine, and so that the sides of the V-notch are
symmetrically located with the line through the mid-points of the clamps.
NOTE The stirrup may be fastened in the upper clamp, if desired. This procedure will require rebalancing the
tension-testing machine to compensate for the mass of the stirrup.
Place the lower clamp of the machine so that the lower edge of the upper clamp is about
90 mm above the upper edge of the V-notched plate.
Thread the test piece through the stirrup, under the plate, and bring the two ends together and
fasten them in the upper clamp.
In this operation, most of the slack in the test piece is taken up, but care shall be exercised not
to apply a tearing force to the test piece. Make the application of the first increments of load to
the test piece very slowly if possible, to minimize abnormal strains due to inertia effects.
Increase the load so that tearing starts in 5 s to 15 s and record this load in newtons.

60554-2  IEC:2001 – 23 –
10.4 Results
Report the central values for each of the two directions of the paper in newtons, mentioning the
thickness of the plate used, the rate of loading and the width and thickness of the test pieces.
11 Bursting strength
The bursting strength shall be determined according to the method described in ISO 2758, with
the following exceptions:
– the test pieces shall be conditioned in accordance with clause 4.
Principle
A test piece, placed in contact with a circular elastic diaphragm, is rigidly clamped at the
periphery but free to bulge with the diaphragm. Hydraulic fluid is pumped at a constant rate,
bulging the diaphragm until the test piece ruptures. The bursting strength of the test piece is
the maximum value of the applied hydraulic pressure.
12 Folding endurance
12.1 Test apparatus
A folding tester (Schopper type).
12.2 Test pieces
Nine strips 15 mm wide, cut in the machine direction, and nine other strips cut in the cross
direction.
12.3 Procedure
Clamp the specimen in both clamps. Apply a tension of 5 N for specimens of up to 0,03 mm in
thickness and a tension of 10 N for thicker specimens. Determine the number of double folds
which the paper withstands, applying a plate of 0,5 mm in thickness with a radius of curvature
of 0,25 mm, at a speed of 100 to 200 double folds per minute.
12.4 Results
Report the central value of each series to two significant figures. The highest and lowest values
shall also be reported.
13 Moisture content
The moisture content of the paper, as received, shall be measured according to the method
described in ISO 287 (oven-drying method). The result shall be expressed as percentage
moisture of the original mass. Three test specimens shall be taken according to ISO 287.
Principle
Weigh the test piece at the time of sampling and again after drying in an oven at 102 °C to
105 °C to constant mass.
60554-2  IEC:2001 – 25 –
14 Ash content
The amount of residue of paper left after incineration shall be determined according to the
method described in ISO 2144.
Three determinations shall be made. The result shall be expressed as a percentage of the
oven dry mass.
15 Conductivity of aqueous extract
15.1 Test apparatus
– A conductivity cell with known cell constant K.
– A conductance or inductance measuring instrument, capable of measuring conductance to a
minimum reading of 1 μS with an accuracy of 5 %, in the frequency range 50 Hz to 3 000 Hz.
Alternatively, the resistance may be measured with the same accuracy.
– Wide-mouth 250 cm conical flasks with reflux condensers in acid- and alkali-resistant
glass.
15.2 Procedure
The determination is to be made on the material as received. One measurement shall be made
on each of three extractions. First, a blank test shall be carried out on water which has been
boiled for 60 min ± 5 min in the flask to be used. If the conductivity of that water is not more
than 200 μS/m, the flask may be used. If the conductivity is higher than this value, then the
flask shall be boiled with a fresh portion of water. If the conductivity of the second test exceeds
200 μS/m, then another flask shall be used.
The test on the paper shall then be carried out as follows.
Cut a test specimen weighing approximately 20 g into pieces of about 10 mm × 10 mm. Weigh
approximately 5 g into a 250 cm glass flask with a reflux condenser and add approximately
100 cm water having a conductivity of not more than 200 μS/m. The water shall be boiled
gently for 60 min ± 5 min, and then cooled in the flask to room temperature. It is necessary to
take precautions against the absorption of carbon dioxide from the air.
The extract is then decanted into the measuring vessel for the conductivity to be measured
immediately. The measuring vessel shall be rinsed twice with the extract. The measurement of
the conductivity shall be made at 23 °C ± 0,5 K.
NOTE 1 Extraction in accordance with method 1 of clause 17 is an acceptable alternative, but 5 g in 100 cm is to be
used.
NOTE 2 It is essential to ensure, during the taking, storing and manipulation of specimens and test portions
intended for conductivity, pH and chloride content of aqueous extract tests, that they are not contaminated either by
the atmosphere, particularly the atmosphere of a chemical laboratory, or by handling with bare hands.

60554-2  IEC:2001 – 27 –
15.3 Results
Calculate the conductivity of the extract solution as follows:
γ = K (G – G )
1 2
where
γ is the conductivity of extract solution, expressed in microsiemens per metre (μS/m);
–1
K is the cell constant, expressed in m ;
G is the conductance of the extract solution, expressed in microsiemens (μS);
G is the conductance of the blank test, expressed in microsiemens (μS).
16 pH of aqueous extract
16.1 Test apparatus
– A pH-meter with glass and calomel electrodes having a sensitivity of at least 0,05 pH units.
– Wide-mouth 250 cm conical flasks in acid- and alkali-resistant glass.
16.2 Procedure
One measurement shall be made on each of three extractions.
Prepare an extract as described in 15.2.
The extract shall be decanted only for immediate use, avoiding unnecessary exposure to the
atmosphere. Calibrate the pH-meter with a buffer solution having a pH value within ±2 pH units
of that of the extract. Remove the electrodes from the buffer solution and wash them well by
rinsing several times in distilled water and once in a small quantity of extract.
Immerse the electrodes in the unfiltered extract and measure the pH value of the extract at
23 °C ± 2 K.
NOTE 1 If the extract is to be used for the determination of conductivity, the sample for this determination should
be drawn from the aqueous extract prior to the pH determination. This is because potassium chloride, which
diffuses from the calomel electrode, would otherwise affect the result.
NOTE 2 See note 2 of 15.2.
16.3 Results
Report the central value as the result; the highest and lowest values are reported.

60554-2  IEC:2001 – 29 –
17 Chloride content of aqueous extract
17.1 Method 1
17.1.1 Precautions
All apparatus for use in this test shall be scrupulously clean. It is suggested that all flasks,
beakers and funnels be boiled in de-ionized water after normal cleaning and rinsing. Handling
of apparatus should be by stainless steel tongs. Similarly, forceps and scissors for sample
preparation should be of stainless steel and kept clean in the same way.
NOTE See also note 2 of 15.2.
17.1.2 Test apparatus
– A measuring device capable of measuring a d.c. voltage in the range 0 mV to 300 mV
with an accuracy of 2 mV (for example, an electronic voltmeter or potentiometer such as a
pH-meter).
– A 600 cm flat-bottom high-grade resistance glass or quartz flask.
– A steam bath.
– An analytical balance.
– A glass micrometer syringe (method 1 only).
– A microburette graduated in 0,01 cm divisions (method 2 only).
– A magnetic stirring device.
– Measuring cylinders, beakers, filter funnels, rods and needles, etc.
– Fast-grade filter papers.
17.1.3 Procedure
One determination shall be made on each of three extractions. For each extraction, the paper
shall be cut into strips approximately 50 mm × 10 mm. A mass of approximately 20 g shall be
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placed in a 600 cm flat-bottom flask and approximately 300 cm of boiling de-ionized or
distilled water, fulfilling the conductivity requirements of clause 15, added.
The mixture shall be kept in a steam bath for 60 min ± 5 min, the mouth of the flask being
covered by a loosely fitting beaker placed over the neck.
The suspension shall then be filtered using suction through a pre-extracted filter paper in a
Buchner funnel. A flat-ended rod is used to compress the cake of paper residue in order to
express as much extract as possible.
The volume of the extract shall be measured and the residual cake weighed (W).
The extract shall be returned to a flask similar to the extraction flask and evaporated to
dryness in a hot-water bath; contamination is prevented by a large beaker (approximately
250 cm ) suspended inverted over the flask.
When completely dry, approximately 20 cm of de-ionized water shall be added to the flask and
the drying repeated.
60554-2  IEC:2001 – 31 –
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The extracted residue shall be dissolved in 5 cm ± 1 % of 10 % HNO , transferred to a 100 cm
beaker and the flask twice washed out into the beaker with 5 cm ± 1 % of acetone.
The chloride content of the extract shall then be determined potentiometrically using a mag-
netic stirrer, a glass reference electrode and a silver-wire indicator with a measuring device, for
example, a pH-meter.
The titrant shall be a solution of AgNO of 0,02 M added in quantities of 0,01 cm from a micro-
meter syringe through a glass needle dripping into the titration cell.
Titrate a reagent blank consisting of the following: (340 – W) cm of water evaporated to
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dryness, 5 cm of 10 % HNO , and 10 cm acetone.
17.1.4 Results
The chloride content of the extract solution shall be expressed as the mass of chloride ion,
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in 10 of the mass of the paper, and shall be calculated as follows:
− −
(AB ) M  W D 
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chloride content (10 ) = 35,46  × 1 +  ×10
 
 
D V
where
M is the molality of the AgNO solution in moles per kilogramme (mol/kg);
D is the mass of the dried paper in grams (g);
3)
A is the volume of AgNO solution used to titrate the extract in cubic centimetres (cm ;
3)
B is the volume of AgNO solution used to titrate the blank in cubic centimetres (cm ;
W is the mass of wet paper residue in grams (g);
3)
V is the volume of extract in cubic centimetres (cm .
The result is the central value of the three determinations.
17.2 Method 2
17.2.1 This method deviates from method 1 in the following details:
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– four grams of paper are treated in 100 cm of water instead of 20 g in 300 cm ;
– vigorous boiling is carried out for 60 min ± 5 min;
– treatment of the extract is as follows
a) filter or decant the cooled extract solution and weigh 25 g ± 0,1 g into a 200 cm tall-
form beaker. Add 125 cm of acetone and 15 drops of 1 % nitric acid;
b) place a stirring rod into the beaker, then place the beaker on the magnetic stirrer and
adjust the stirring speed so that the surface of the liquid is not broken;
c) immerse the electrodes in the liquid and allow the meter to stabilize, then start titrating;
d) from the microburette, add 0,0025 M AgNO solution in 0,01 cm increments and record
the change of potential in millivolts, mV;
e) titrate to an end-point that represents the point of the greatest change in potential, or to
a fixed point that has been previously determined from a potentiometric curve;

60554-2  IEC:2001 – 33 –
f) record the total volume of solution, in cm , used to reach the end-point;
g) duplicate titrations should be run on each extract and should concord to ± 0,01 cm .
Duplicate specimens should concord within ±5 % except at low levels wher
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