SIST EN 60672-2:2001

Ceramic and glass insulating materials -- Part 2: Methods of test

Applicable to ceramic, glass and glass-ceramic materials to be used for electrical insulation purposes. Specifies methods of test. Intended to provide test results typical of the material from which the test pieces are processed. Since, in the majority of cases, ceramic components for insulating purposes are of rather different size and shape to test pieces, the results of such tests provide only a guide to the actual properties of components. The limitations imposed by the method of forming and processing are discussed where relevant.

Keramik- und Glasisolierstoffe -- Teil 2: Prüfverfahren

Matériaux isolants à base de céramique ou de verre -- Partie 2: Méthodes d'essai

S'applique à des matériaux à base de céramique, de verre et de verre-céramique destinés à être utilisés à des fins d'isolation électrique. Spécifie les méthodes d'essai. Elle est destinée à fournir des résultats d'essai qui sont représentatifs du matériau dans lequel les éprouvettes sont prises. Comme, dans la majorité des cas, les composants en céramique destinés à l'isolation électrique sont des éprouvettes de dimensions et de formes plutôt différentes, le résultat de tels essais fournit uniquement un guide pour les propriétés réelles des composants. Les limitations imposées par la méthode utilisée pour les former et les traiter sont étudiées en conséquence.

Ceramic and glass insulating materials - Part 2: Methods of test (IEC 60672-2:1999)

General Information

• Status: Published
• Publication Date: 28-Feb-2001
• ICS: 29.035.30 - Glass and ceramic insulating materials
• Technical Committee: IZO - Insulating materials
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Mar-2001
• Due Date: 01-Mar-2001
• Completion Date: 01-Mar-2001
• Ref Project: EN 60672-2:2000 - Ceramic and glass insulating materials - Part 2: Methods of test

Relations

• Replaces: SIST HD 426.2 S1:1998 - Specification for ceramic and glass insulating materials -- Part 2: Methods of test
• Effective Date: 28-Jan-2023
• Revised: SIST HD 426.2 S1:1998 - Specification for ceramic and glass insulating materials -- Part 2: Methods of test
• Effective Date: 13-May-2010
• Replaces: SIST HD 426.2 S1:1998 - Specification for ceramic and glass insulating materials -- Part 2: Methods of test
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 60672-2:2001
01-marec-2001
1DGRPHãþD
SIST HD 426.2 S1:1998
Ceramic and glass insulating materials - Part 2: Methods of test (IEC 60672-2:1999)
Ceramic and glass insulating materials -- Part 2: Methods of test
Keramik- und Glasisolierstoffe -- Teil 2: Prüfverfahren
Matériaux isolants à base de céramique ou de verre -- Partie 2: Méthodes d'essai
Ta slovenski standard je istoveten z: EN 60672-2:2000
ICS:
29.035.30 .HUDPLþQLLQVWHNOHQL Ceramic and glass insulating
L]RODFLMVNLPDWHULDOL materials
SIST EN 60672-2:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60672-2:2001

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SIST EN 60672-2:2001

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SIST EN 60672-2:2001

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SIST EN 60672-2:2001

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SIST EN 60672-2:2001

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SIST EN 60672-2:2001


INTERNATIONAL IEC


STANDARD 60672-2





Second edition
1999-12


Ceramic and glass insulating materials –
Part 2:
Methods of test

 IEC 1999 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: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
X
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 3 –
CONTENTS
Page
FOREWORD . 7
Clause
1 Scope . 11
2 Normative references. 11
3 General notes on tests. 13
4 Dye penetration test (liquid absorption). 17
5 Bulk density and open (apparent) porosity . 19
6 Flexural strength. 25
7 Modulus of elasticity . 33
8 Mean coefficient of linear thermal expansion. 41
9 Specific heat capacity . 45
10 Thermal conductivity . 47
11 Resistance to thermal shock . 49
12 Glass transition temperature (for glass materials only). 53
13 Electric strength.55
14 Withstand voltage . 61
15 Relative permittivity, temperature coefficient of permittivity and dissipation factor . 63
16 Volume resistivity. 67
Annex A (normative) Standard temperature conditions for testing. 85
Bibliography . 87
Figure 1 – Apparatus for applying high pressure to dye solution contained
in a metal container. 71
Figure 2 – Function of mechanical testing jigs and symbols for strength tests . 73
Figure 3 – Shape, symbols and dimensions of flexural strength test pieces . 75
Figure 4 – Deflection parameters and method of determination of deflections
for Young's modulus determination. 77
Figure 5 – Graphical construction for determination of transition temperature T of glasses . 79
g
Figure 6 – Test piece for electrical strength and withstand voltage tests, method B. 81
Figure 7 – Electrode arrangement for electric strength measurement, method A . 83

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 5 –
Page
Table 1 – Characteristics and minimum number of test pieces for each test . 15
Table 2 – Density of distilled water. 23
Table 3 – Dimensions of test pieces and flexural strength test jig
for various groups of ceramic materials . 29
Table 4 – Dimensions of test pieces for method B (see also figure 6) . 57
Table 5 – Values of k for various values of thickness of test pieces. 59
Table A.1 – Standard temperature conditions for testing . 85

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
–––––––––––––
CERAMIC AND GLASS INSULATING MATERIALS –
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 60672-2 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 1980 and constitutes a
technical revision. In redrafting this standard, the intention has been to improve the
instructions in the test methods so that the document becomes more usable in the testing
laboratory. Some of the ambiguities of test conditions have been removed, particularly for
mechanical testing for which the recent development of improved understanding of significant
factors in testing has allowed a better definition of requirements and a restriction of the range
of previously optional test piece sizes.
The text of this standard is based on the following documents:
FDIS Report on voting
15C/1049/FDIS 15C/1069/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.

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 9 –
IEC 60672 consists of the following parts under the general title Ceramic and glass insulating
materials:
Part 1:1995, Definitions and classification;
Part 2:1999, Methods of test;
Part 3:1997, Specifications for individual materials.
Annex A forms an integral part of this standard.
The committee has decided that this publication remains valid until 2008. At this date, in
accordance with the committee’s decision, the publication will be
reconfirmed;
withdrawn;
replaced by a revised edition, or
amended.

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 11 –
CERAMIC AND GLASS INSULATING MATERIALS –
Part 2: Methods of test
1 Scope
This part of IEC 60672 is applicable to ceramic, glass and glass-ceramic materials to be used
for electrical insulation purposes. This standard specifies methods of test. It is intended to
provide test results typical of the material from which the test pieces are processed. Since, in
the majority of cases, ceramic components for insulating purposes are of rather different size
and shape to test pieces, the results of such tests provide only a guide to the actual
properties of components. The limitations imposed by the method of forming and processing
are discussed where relevant.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60672. 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 60672 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 ISO
and IEC maintain registers of currently valid International Standards.
IEC 60093:1980, Methods of test for volume resistivity and surface resistivity of solid
electrical insulating materials
IEC 60212:1971, Standard conditions for use prior to and during the testing of solid electrical
insulating materials
IEC 60243-1:1998, Electric strength of insulating materials – Test methods – Part 1: Tests at
power frequencies
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 60345:1971, Method of test for electrical resistance and resistivity of insulating materials
at elevated temperatures
IEC 60672-1:1995, Ceramic and glass insulating materials – Part 1: Definitions and
classification
IEC 60672-3:1997, Ceramic and glass insulating materials – Part 3: Specifications for
individual materials
IEC 61006:1991, Methods of test for the determination of the glass transition temperature of
electrical insulating materials

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 13 –
ISO/DIS 463, Geometrical product specifications (GPS) – Dimensional measuring instruments –
1)
Dial gauges – Design and metrological requirements (Revision of ISO/R 463:1965)
ISO 758:1976, Liquid chemical products for industrial use – Determination of density at 20 °C
ISO 3534-1:1993, Statistics – Vocabulary and symbols – Part 1: Probability and general
statistical terms
ISO 3611:1978, Micrometer callipers for external measurement
ISO 6906:1984, Vernier callipers reading to 0,02 mm
ISO 7884-8:1987, Glass – Viscosity and viscometric fixed points – Part 8: Determination of
(dilatometric) transformation temperature
3 General notes on tests
3.1 Test pieces
Test pieces shall be processed under conditions closely similar to those normally employed
for the manufacture of components, and in sufficient numbers to be representative of those
conditions. It is emphasized that results from the test pieces are affected by the method of
forming and, in many cases, by the method of surface finishing; methods used should, as far
as possible, be those used in the production of items. For each test result reported, the
method of manufacture of the test piece shall be specified. All numerical values determined
according to these test methods apply only to the test pieces prescribed. They cannot be
extended to test pieces and ceramic products of other shapes and dimensions nor of other
types of manufacture. The minimum number of test pieces for each test is given in table 1.
NOTE For thermally toughened glass test pieces, the thermally pre-stressed state of glass depends on the
following factors:
– thermal expansion below and above the transition range (see IEC 61006);
– viscosity/temperature relation;
– thermal diffusivity, i.e. thermal conductivity (specific heat capacity × bulk density);
– elastic properties;
– starting temperature of cooling;
– heat transfer coefficient;
– thickness and form of glass product.
As a result of the last factor, test pieces from the same glass but of different shape and thickness have different
tempering levels, although they are tempered under the same conditions. Consequently, it is impossible to have a
special test piece which represents the properties of toughened glass items of other shapes and thickness.
Therefore, physical properties of thermally tempered glass items which show corresponding dependence on the
tempering state can be determined only on the item itself, and it is recommended that this procedure is adopted
whenever possible. This applies to properties such as flexural strength, resistance to thermal shock, volume
resistivity and dissipation factor.
––––––––––
1)
To be published.

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 15 –
Table 1 – Characteristics and minimum number of test pieces for each test
Clause Test Number of Shape and dimensions
test pieces
4 Dye penetration test 3 Fragments or small components; see 4.2
5 Bulk density/ 3 Fragments or small components;
open porosity see 5.2, note
6 Flexural strength 10 See table 3
7 Modulus of elasticity 3 Bar-shaped, preferably with a support
span-to-thickness ratio > 50; see 7.3
8 Mean coefficient of linear 2 Appropriate to the apparatus used
thermal expansion
9 Specific heat capacity 2 Appropriate to the apparatus used
10 Thermal conductivity 2 Appropriate to the apparatus used;
see 10.2
11 Thermal shock 30
Rods 10 mm diameter × 120 mm long
12 Glass transition temperature 2 Appropriate to the apparatus used
(T , for glass only)
g
13 Electric strength 10 Discs as described in 13.3
14 Withstand voltage 10 Discs as described in 13.3
15 Relative permittivity/ 3 Discs in accordance with IEC 60250,
dissipation factor as described in clause 15
16 Volume resistivity 2 Discs in accordance with IEC 60345,
as described in clause 16
3.2 Presentation of results
The test report shall include the following:
a) name of testing establishment;
b) a reference to this standard;
c) date of test;
d) identification of the item, test piece or test material (type, manufacturer, shaping process,
batch number, date of manufacture, etc., as appropriate);
e) the test performed;
f) the preparation, shape and dimensions of the test pieces and the number tested (see
table 1 for the minimum number for each test);
g) details relevant to the test or tests undertaken (see requirements listed under each test
method);
h) individual results from each test piece;
i) the arithmetic mean value of the individual results, and the standard deviation.
3.3 Evaluation against a minimum specification
For the purpose of assessing whether a material has satisfactory properties compared with
the minimum specification laid down in IEC 60672-3, the mean value of the specified number
of determinations shall be compared with the maximum or minimum value required in
IEC 60672-3, or with the range of values permitted.

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 17 –
4 Dye penetration test (liquid absorption)
NOTE 1 This test is intended to detect the presence of continuous interconnected porosity or microcracks which
would render the material unsatisfactory from the high-voltage dielectric breakdown point of view. The test is not
applicable to glass materials with the exception of sintered glass products. The test is also not intended as a
routine inspection test for minor cracks or pores in small components, for which alternative less stringent tests, for
example a liquid dye vacuum test, may be appropriate.
NOTE 2 For dark-coloured materials, the dye chosen should be such as to give contrast with the natural colour of
the material. Fluorescent dyes may be appropriate, but only if used as described in 4.4.
4.1 Test apparatus
The test apparatus shall include a pressure vessel capable of withstanding a pressure of
at least 30 MPa, a high-pressure pump and a pressure gauge. Test pieces are immersed in
dye solution which either directly fills the pressure vessel, or is contained in a metal container
inside the pressure vessel to which pressure can be transmitted by the pressurizing
hydraulic oil through a rubber bung or piston (see figure 1). An oven capable of maintaining
120 °C ± 5 °C is required for test piece conditioning.
Test pieces
4.2
Fragments of ceramic shall be used. No more than 25 % of the total surface area may be
glazed or have an "as-fired" skin. The test shall be made on fragments from at least three
separate components or test pieces.
4.3 Dye
The dye solution shall be prepared containing typically 1 g to 3 g of dye in 1 l of ethyl alcohol
or methylated spirits, or other suitable solvent.
NOTE 1 Suitable non-toxic dyes include xanthan/triaryl methane mixtures.
NOTE 2 Due regard should be paid to health hazards and environmental implications of using and disposing of
organic dyes and solvents.
4.4 Method of test
The test pieces shall be free from oil or dirt of any type, and shall be washed if necessary.
The test pieces shall be dried at 120 °C ± 5 °C for a period of not less than 3 h prior to the
test, and are then broken into fragments of appropriate size.
The test pieces shall be immersed in the dye solution, which is either directly in the pressure
vessel, or in the metal container sealed with the rubber seal or piston which is then placed in
the pressurising vessel. The system shall be pressurized to not less than 15 MPa, and for a
time period such that the product of pressure in megapascals (MPa) and time in hours (h) is
not less than 180. After the appropriate time, the fragments shall be taken from the system,
washed in water, dried and broken. The freshly broken surfaces shall be examined, using
normal vision for any sign of penetration of the dyestuff. These surfaces shall show no
penetration. Penetration of dye into small cracks, produced when initially preparing fragments,
shall not be taken into consideration.

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 19 –
4.5 Test report
In addition to the information required under items a) to i) in 3.2, the test report shall contain
the following:
a) the pressure, in MPa, and the time under pressure, in h;
b) the size, shape and number of test pieces and the fragments produced therefrom;
c) whether or not penetration of dye was observed on any freshly fractured surface of
fragment.
5 Bulk density and open (apparent) porosity
NOTE 1 These methods are not appropriate for the determination of open porosity levels of less than 0,5 % by
volume, since reliable numerical results cannot be obtained. The existence of such porosity levels can be more
reliably determined using the dye test described in clause 4.
NOTE 2 These tests are appropriate for the determination of the bulk characteristics of materials. It should be
noted that as-fired skins on ceramic components may be impervious, even if bulk material may have some open
porosity.
NOTE 3 The use of liquid immersion media other than distilled water is permissible provided that the density of
–3
the liquid is measured to ±0,001 Mg.m at the temperature of the weighings of the immersed test piece. Suitable
liquids include paraffin, butyl alcohol and other organic liquids of low volatility.
NOTE 4 By agreement, other methods, for example gas pyknometry, may be used, but the results may not be
comparable to those produced by the methods described below.
5.1 Test apparatus
The following apparatus is required for this test:
a) a hydrostatic balance (a balance suitable for determining the apparent mass of a test
piece suspended in a liquid) capable of weighing to an accuracy of ±0,01 g;
b) a thin, de-greased metallic suspension wire of diameter not exceeding 0,20 mm;
c) either:
method A: a gas-tight vessel (bell jar or desiccator) connected to a suitable vacuum pump,
and which is provided with suitable means for measuring the pressure and for admitting
liquid, or
method B: a vessel for containing boiling water and equipped with non-corrodable wide-
mesh netting to support the test piece(s) positioned at least 10 mm above the base of the
vessel;
NOTE Method B is not recommended if inflammable organic liquids are to be used owing to potential safety
hazards.
d) an oven for drying test pieces;
e) a lint-free cloth for removing excess liquid from test pieces;
f) a supply of demineralized or freshly distilled water, or other suitable liquid (see note 3
above).

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 21 –
5.2 Test pieces
At least three determinations shall be made. If an open porosity determination is required,
each test shall employ at least three fragments of ceramic material with a total mass of
between 50 g and 80 g. No more than 25 % of the surface may be either glazed or have an
"as-fired" skin. The fragments shall be clean and degreased. Any chips liable to become
detached during the test and any loose dust shall be removed by brushing before the test.
NOTE If density determinations are required on individual, small components weighing less than 50 g each,
the method cited here may be used provided that the accuracy of weighing is ±0,001 g for test pieces of greater
than 3 g mass, or ±0,0001 g for test pieces of 1 g to 3 g mass. For components of mass less than 1 g the methods
described below are not adequate, and several components should be tested together to make a larger mass.
Individual components should not have a mass of less than 0,1 g.
5.3 Method of test
Dry the test piece fragments in the oven at 120 °C ± 5 °C for at least 2 h and until constant
mass m is achieved.
o
Method A: Place the test piece fragments in a suitable container inside the vacuum vessel.
Close the vessel and evacuate it to a pressure of less than 3 kPa and maintain this for at
least 5 min. Isolate the vessel from the vacuum pump and observe any steady rise in
pressure. If a rise to greater than 4 kPa occurs in less than 5 min, the test piece is continuing
to out-gas. Reconnect the vacuum pump and continue evacuating until there is no significant
change in a 5 min period on isolation of the vacuum vessel. Admit freshly boiled distilled
water at 23 °C ± 2 °C to the test piece in the container until the test piece is covered, and
continue evacuation for a further period of at least 5 min. After this period, isolate the vacuum
pump and admit air to the vessel, and remove the test piece in its container of water. For low-
porosity materials, allow to stand in distilled water for at least 6 h.
Method B: Place the test piece fragments in the vessel and cover with distilled water. Heat to
boiling point and boil for at least 30 min; then allow to cool to room temperature while still
immersed, and stand in distilled water for at least 6 h.
NOTE Method A and method B may not give exactly equivalent results for open-porosity determination, method B
being considered to be less effective in removing entrained air from the test pieces.
Whichever method is used, weigh the test piece fragments in distilled water, using a thin,
clean metal suspension wire (m ). Remove the test pieces and replace in the distilled water.
w
Weigh the suspension wire submerged to the same depth as when used for weighing the
immersed test pieces (m ). Record the temperature of the water (T) to the nearest 0,1 °C.
s
Remove the test piece fragments from the water, wipe each with the damp lint-free cloth to
remove surface water only, and reweigh in air (m ).
h

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 23 –
5.4 Calculation of results
Calculate the bulk density (ρ ) and open (apparent) porosity (p ) as follows:
a a
m × ρ m − m
o w h o
ρ = p = × 100 (1)
a a
m − m + m m − m + m
h w s h w s
where
–3
ρ is the bulk density, in Mg⋅m ;
a
p is the open (apparent) porosity, in vol %;
a
m is the mass of the dry test piece, in g;
o
m is the apparent mass of the test piece and suspension wire immersed in water, in g;
w
m is the apparent mass of the suspension wire immersed to same level in water, in g;
s
m is the mass of the soaked test piece in air, in g;
h
–3
ρ is the density of water or other immersion liquid at the test temperature T, in Mg⋅m .
w
The density of distilled water at temperature T is given in table 2. If a liquid other than distilled
water is used, its density shall be determined following the procedure laid down in ISO 758 at
the same temperature as used for the test piece density determination.
Table 2 – Density of distilled water
Temperature Density
o
–3
C ρ , Mg⋅m
w
18 0,99860
19 0,99841
20 0,99820
21 0,99799
22 0,99777
23 0,99754
24 0,99730
25 0,99704
26 0,99678
5.5 Test report
In addition to the information required under items a) to i) in 3.2, the test report shall include
the following:
a) the method used (method A or method B);
b) the immersion liquid used, if not distilled water;
c) the temperature at which the density determination was made, in °C;
–3
d) the density of the immersion liquid at the test temperature, in Mg⋅m ;
e) the time taken to complete the soaking of the test piece, in h;
–3 –3
f) the individual values of bulk density, in Mg⋅m (rounded to the nearest 0,01 Mg⋅m ), and
open porosity, in % (rounded to the nearest 0,1 %), determined on each test piece.

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SIST EN 60672-2:2001
60672-2 © IEC:1999 – 25 –
6 Flexural strength
NOTE The fracture strength determined from a flexural test depends upon many factors including test piece size
and cross-sectional geometry, surface finish, stressing rate, humidity of the environment, test jig geometry and
mode of operation. The result of such a test gives a guide to the general strength properties of the material, but
cannot be used directly as a figure for design purposes. It can be used as a quality-control check, and for a broad
intercomparison of different materials, provided that relevant test parameters, such as those given above, are kept
constant.
6.1 Test apparatus
The apparatus required for this test includes the following:
a) mechanical testing machine capable of applying a force to a test piece at a constant
loading rate or cross-head movement rate, and of recording peak force applied with an
accuracy of ±1 %;
*
NOTE ISO 7500-1 [2] provides information on the requirements for linearity and resolution of force recording in
mechanical testing machines when used under tensile force, procedures which may be applied also to the
compression mode, such as typically encountered in flexural strength testing.
b) a specimen loading jig of geometry and dimensions appropriate to the test being
performed (see 6.2 and table 3);
c) a micrometer in accordance with ISO 3611 capable of measuring dimensions of test
pieces to an accuracy of ±0,01 mm;
d) a travelling microscope, vernier callipers in accordance with ISO 6906, or other suitable
device for measuring spacing of centres of test piece support and loading rods to an
accuracy of ±0,05 mm.
6.2 Loading jigs
Method A – three-point bend
The test jig or fixture consists of two parallel test piece support rods upon which the test piece
is laid, and one loadi
...