SIST EN 60641-2:2005

SLOVENSKI SIST EN 60641-2:2005

STANDARD
december 2005
Prešpanske plošče in prešpanski papir za električne namene – 2. del:
Preskusne metode (IEC 60641-2:2004)
Pressboard and presspaper for electrical purposes - Part 2: Methods of test (IEC
60641-2:2004)
ICS 29.035.10 Referenčna številka
SIST EN 60641-2:2005(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 60641-2
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2004

ICS 17.220.99 ; 29.935.10 Supersedes EN 60641-2:1995


English version


Pressboard and presspaper for electrical purposes
Part 2: Methods of tests
(IEC 60641-2:2004)


Carton comprimé et papier comprimé  Tafel- und Rollenpressspan
à usages électriques für elektrotechnische Anwendungen
Partie 2: Méthodes d'essai Teil 2: Prüfverfahren
(CEI 60641-2:2004) (IEC 60641-2:2004)






This European Standard was approved by CENELEC on 2004-09-01. 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, 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


© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60641-2:2004 E

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EN 60641-2:2004 - 2 -
Foreword
The text of document 15C/1609/FDIS, future edition 2 of IEC 60641-2, 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 60641-2 on 2004-09-01.
This European Standard supersedes EN 60641-2:1995.
The main changes with respect to EN 60641-2:1995 are listed below:
The following test methods have been cancelled:
– flexibility;
– conductivity of the organic extract;
– contamination of liquid dielectrics.
The following test methods have been rewritten:
– compressibility;
– conductivity of the aqueous extract;
– cohesion between plies.
The following test method has been introduced:
– determination of metallic particles with X-ray.
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) 2005-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-09-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60641-2:2004 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60247 NOTE Harmonized as EN 60247:2004 (not modified).
ISO 186 NOTE Harmonized as EN ISO 186:2002 (not modified).
__________

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- 3 - EN 60641-2:2004
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
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.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60243-1 1998 Electrical strength of insulating materials - EN 60243-1 1998
Test methods
Part 1: Tests at power frequencies

IEC 60296 2003 Fluids for electrotechnical applications - EN 60296 2004
Unused mineral insulating oils for + corr. September 2004
transformers and switchgear

IEC 60554-2 2001 Cellulosic papers for electrical purposes EN 60554-2 2002
Part 2: Methods of test

ISO 287 1985 Paper and board - Determination of EN 20287 1994
moisture content - Oven-drying method

ISO 534 1988 Paper and board - Determination of EN 20534 1993
thickness and apparent bulk density or
apparent sheet density

ISO 1924-2 1994 Paper and board - Determination of EN ISO 1924-2 1995
tensile properties
Part 2: Constant rate of elongation
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

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NORME CEI
INTERNATIONALE IEC
60641-2
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
2004-06
Carton comprimé et papier comprimé
à usages électriques –
Partie 2:
Méthodes d'essai
Pressboard and presspaper
for electrical purposes –
Part 2:
Methods of tests
© IEC 2004 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 any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. 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
CODE PRIX
PRICE CODE U
Commission Electrotechnique Internationale
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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60641-2 © IEC:2004 – 3 –
CONTENTS
FOREWORD.7
1 Scope.11
2 Normative references.11
3 Terms and definitions .13
4 General notes on tests .13
4.1 Conditioning.13
4.2 Drying.13
4.3 Tolerances.13
4.4 Results.15
5 Thickness.15
5.1 Test apparatus.15
5.2 Setting gauge.15
5.3 Procedure.17
5.4 Results.17
6 Apparent density.17
7 Tensile strength and elongation.19
7.1 Principle.19
7.2 Determination with non-folded test pieces .19
7.3 Determination with folded test pieces .19
8 Internal tearing resistance.19
9 Edge tearing resistance.21
9.1 Procedure.21
9.2 Results.21
10 Compressibility.21
10.1 Principle.21
10.2 Test apparatus.21
10.3 Test pieces.21
10.4 Procedure.21
10.5 Results.23
11 Shrinkage.23
11.1 Test apparatus.23
11.2 Test pieces.23
11.3 Procedure.25
11.4 Results.25
12 Plybond resistance .25
12.1 Principle.25
12.2 Test pieces.25
12.3 Test apparatus.25
12.4 Test method.25
12.5 Results.27
13 Moisture content.27
14 Ash content.27

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60641-2 © IEC:2004 – 5 –
15 Conductivity of aqueous extract.29
15.1 Test apparatus.29
15.2 Procedure.29
15.3 Results.29
16 pH of aqueous extract .31
16.1 Test apparatus.31
16.2 Procedure.31
16.3 Results.31
17 Oil absorption.31
17.1 Test pieces.31
17.2 Procedure.31
17.3 Results.33
18 Conducting paths.33
19 Presence of metallic particles .33
19.1 Chemical methods.33
19.2 X-ray method.35
20 Electric strength.39
20.1 Test apparatus.39
20.2 Test pieces for test in air .39
20.3 Test pieces for test in oil .39
20.4 Test pieces for testing after folding.39
20.5 Number of tests.41
20.6 Procedure.41
20.7 Results.41
Bibliography.51
Figure 1 – Folding sequence.43
Figure 2 – Folding apparatus .43
Figure 3 – Double prick punch .45
Figure 4 – Measuring calliper.45
Figure 5 – Plybond resistance tester .47
Figure 6 – Folding device.47
Figure 7 – Folding apparatus (For dimensions, see Figure 2).49

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60641-2 © IEC:2004 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRESSBOARD AND PRESSPAPER
FOR ELECTRICAL PURPOSES –
Part 2: Methods of tests
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of 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, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). 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. 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 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 IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60641-2 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 1979, and amendment
1 (1993). This edition constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
The following test methods have been cancelled:
– Flexibility
– Conductivity of the organic extract
– Contamination of liquid dielectrics

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60641-2 © IEC:2004 – 9 –
The following test methods have been rewritten:
– Compressibility
– Conductivity of the aqueous extract
– Cohesion between plies
The following test method has introduced:
– Determination of metallic particles with X-ray.
The text of this standard is based on the following documents:
FDIS Report on voting
15C/1609IFDIS 15C/1642/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicted in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 60641 consists of the following parts, under the general title Pressboard and presspaper
for electrical purposes:
Part 1: Definition and general requirements (IEC 60641-1)
Part 2: Methods of test (IEC 60641-2)
Part 3: Specifications for individual materials (IEC 60641-3)
Sheet 1: Pressboard
Sheet 2: Presspaper
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

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60641-2 © IEC:2004 – 11 –
PRESSBOARD AND PRESSPAPER
FOR ELECTRICAL PURPOSES –
Part 2: Methods of tests
1 Scope
This part of IEC 60641 applies to pressboard and presspaper for electrical purposes.
The series does not apply to laminated material.
This part specifies the test methods to be used in testing pressboard and presspaper for
electrical purposes to meet the requirements prescribed in the specification sheets of Part 3.
NOTE 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 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 60243-1:1998, Electrical strength of insulating materials – Test methods – Part 1: Tests
at power frequencies
IEC 60296:2003, Fluids for electrotechnical applications – Unused mineral insulating oils for
transformers and switchgear
IEC 60554-2:2001, Cellulosic papers for electrical purposes – Part 2: Methods of test
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
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

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60641-2 © IEC:2004 – 13 –
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
specimen
rectangle of paper or board cut to given dimensions from sheets or reels drawn from selected
units
3.2
test piece
quantity of paper or board on which each single determination is carried out in accordance
with the method of test.
NOTE The test piece may be taken from a specimen; in some instances, it may be the specimen itself.
4 General notes on tests
4.1 Conditioning
a) For materials with a thickness of <0,5 mm
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
shall be cut from the specimen and tested in this atmosphere.
b) For materials with a thickness of ≥0,5 mm
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
shall be cut from the specimen and tested in an atmosphere of 20 °C to 30 °C and 40 % to
60 % relative humidity.
In case of dispute, the conditioning shall be 23 °C ± 2 K and (50 ± 5) % relative humidity until
the moisture content of the specimen reaches 5,5 % to 8 %. The conditioning shall be
approached from the dry side after drying at 70 °C ± 5 K for a period sufficient to ensure that
the conditioning atmosphere produces a mass increase in the specimen.
4.2 Drying
Unless otherwise specified, the following drying procedure shall be used.
Dry the test pieces in a ventilated oven at 105 °C ± 5 K.
The minimum drying time as a function of the thickness s expressed in millimetres shall be as
follows:
Nominal thickness s (mm) ≤ 0,5 0,5 < s ≤ 1,5 1,5 < s ≤ 5 > 5
Time (h) 12 24 48 72
4.3 Tolerances
When tolerances are not specified for the dimensions of the test piece, it is understood that
these dimensions are taken to the nearest millimetre.

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60641-2 © IEC:2004 – 15 –
4.4 Results
As a general rule, the central value is reported as the result. When agreed between parties,
the mean value may be reported. This must be noted in the test report.
5 Thickness
2
For material with a grammage of less than 224 g/m , use the procedure as described in
2
ISO 534. For materials with a grammage of 224 g/m or more, use the following test:
5.1 Test apparatus
One of the test apparatus described below shall be used.
NOTE In case of dispute, the test apparatus should be the one described in 5.1.2.
5.1.1 Screw type micrometer
An external screw type micrometer having measuring faces of 6 mm to 8 mm diameter. The
measuring faces shall be flat to within 0,001 mm and parallel to within 0,003 mm. The pitch of
the screw shall be 0,5 mm and the graduations shall be 50 divisions 0,01 mm, enabling
readings to be estimated to 0,002 mm. The pressure exerted on the test piece shall be
0,1 MPa to 0,3 MPa.
NOTE For thin, soft material (for instance, board type B.5.1, 1 mm) the error due to the pressure of the
micrometer can be as great as 2 % of the measured value.
5.1.2 Dead weight micrometer
A dead weight dial type micrometer having two ground and lapped measuring concentric
circular surfaces flat to within 0,001 mm and parallel to within 0,003 mm. The upper surface
shall be 6 mm to 8 mm diameter. The lower surface shall be larger than the upper surface.
The upper surface shall move on the axis perpendicular to the surfaces. The dial shall be
graduated to read directly to 0,002 mm. The frame of the micrometer shall be of such rigidity
that a force of 15 N applied to the dial housing, out of contact with either the weight or the
presser foot spindle, will produce a deflection of frame not greater than 0,002 mm as
indicated on the micrometer dial. The pressure exerted on the test piece shall be 0,1 MPa to
0,3 MPa.
5.1.3 Dial gauge micrometer
As an alternative to 5.1.2, a "Dial gauge type micrometer" with the following characteristics
may be used:
Diameter of the upper measuring surface: (14,3 ± 0,5) mm.
Diameter of the lower measuring surface: bigger than the upper one.
Pressure exerted on the test piece: (0,055 ± 0,005) MPa.
The two measuring surfaces shall be parallel to within 0,005 mm or 1 %.
NOTE The values recorded with this apparatus could be significantly different from the ones recorded with the two
other types.
5.2 Setting gauge
The setting gauge used to check the instruments shall be accurate to within ±0,001 mm of
nominal thickness. The thickness indicated by the instruments shall not differ by more than
0,005 mm from the gauge block.

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60641-2 © IEC:2004 – 17 –
5.3 Procedure
Measure the thickness of the pressboard or the presspaper in the as received condition using
one of the instruments described in 5.1 at points not less than 20 mm from the edges.
For the pressboard, the number of measurements shall be eight, two along each edge. For
presspaper in reels, 5.1 of IEC 60554-2 must be followed. When measuring across the width
of a reel, the number of measurements shall be five per metre.
In case of dispute, cut a strip 40 mm wide across the full width of the material and, from this
strip, at eight equally spaced positions, cut eight test pieces, each not less than 40 mm long.
Condition the test pieces in accordance with 4.1 and measure the thickness of each specimen
at a point near the centre of each test piece using the instrument described in 5.1.2.
5.4 Results
The central value is taken as the result and reported together with the minimum and maximum
values.
6 Apparent density
The test shall be carried out on three conditioned test pieces; one determination is made on
each of the three test pieces.
2
Use rectangular test pieces of an area not less than 100 cm and determine the mass to an
–4
accuracy of 10 × mass of test piece.
Make two measurements of the length and two of the width of each test piece to an accuracy
of 0,1 mm at points at least 12 mm from the corners.
Determine the thickness by making eight measurements as indicated in 5.3 and calculate the
mean value of the measurements.
3
Express the apparent density ρ (the mass to volume ratio) a
...