ISO 13821:2020

INTERNATIONAL ISO
STANDARD 13821
Second edition
2020-06
Corrugated fibreboard —
Determination of edgewise crush
resistance — Waxed edge method
Carton ondulé — Détermination de la résistance à la compression sur
chant — Méthode du bord paraffiné
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus and test liquid . 1
6 Sampling . 2
7 Conditioning . 3
8 Preparation of test pieces . 3
8.1 General . 3
8.2 Cutting the test pieces . 3
8.3 Waxing . 3
9 Procedure. 4
10 Calculation . 4
11 Precision . 4
11.1 General . 4
11.2 Precision data from TAPPI-CTS . 5
12 Test report . 5
Bibliography . 6
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 6/SC 2, Test methods and quality
specifications for paper and board.
This second edition cancels and replaces the first edition (ISO 13821:2002), of which it constitutes a
minor revision.
The main changes compared to the previous edition are as follows:
— Introduction of an additional group in the Introduction clause;
— Information on sampling of corrugated shipping containers are added in Clause 6;
— Information in 8.2 on the height of the test pieces;
— Introduction of precision data based on TAPPI comparative testing service.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

Introduction
A variety of methods for the determination of edgewise crush resistance are in use in different parts of
the world. These can be classified into four groups as follows:
a) Those in which a carefully cut rectangular test piece is tested without any special treatment or
modification.
b) Those in which the edges of the test piece to which the force is applied are waxed to prevent the
test result from being influenced by “edge effects”.
c) Those in which the test piece edges are not waxed but the shape of the test piece is such that the
length is substantially reduced at a point midway between the loading edges in order to induce the
failure to occur away from those edges.
d) Those in which carefully cut rectangular pieces are tested with edges clamped to prevent the test
result from being influenced by "edge effects".
The dimensions of the test piece vary from one group to the other and, in group c), the methods vary
according to the shape and method of reducing the length.
The methods may not give the same numerical results, but it can be shown that most of them can be
used to predict the top-to-bottom compression strength which will be achieved when the board is
properly converted into a transport package.
This document describes a method from group b) intended to be used for quality measurement and
quality specification purposes. This particular method is selected because it correlates well with the
top-to-bottom compression strength of the final transport package and provides significantly higher
results than unwaxed methods (a) because edge effects are avoided.
INTERNATIONAL STANDARD ISO 13821:2020(E)
Corrugated fibreboard — Determination of edgewise crush
resistance — Waxed edge method
1 Scope
This document specifies a method for the determination of the edgewise crush resistance of corrugated
fibreboard. The force is applied in the direction of the flute axis.
This method is applicable to single-wall (double-faced), double-wall, and triple-wall corrugated
fibreboard. It may also be used to test samples taken from corrugated cases and other converted
products.
While the method is applicable to waxed corrugated fibreboard, care must be taken that the heat used
in the waxing step does not affect the corrugated structure. This is controlled by observing that failure
during the test still occurs away from the loaded edges.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 186, Paper and board — Sampling to determine average quality
ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
ISO 13820, Paper, board and corrugated fibreboard — Description and calibration of compression-testing
equipment
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
Subjection of a rectangular test piece of corrugated board placed between the platens of a crush tester,
with the flutes perpendicular to the platens, to a compressive force until failure occurs. The loading
edges of the test piece have been reinforced by paraffin to prevent premature failure at those edges
when the load is applied.
Measurement of the maximum force sustained by the test piece.
5 Apparatus and test liquid
5.1 Motor-driven, platen-type compression testing machine. The apparatus described in ISO 13820
shall be used.
5.2 Cutting equipment, enabling the cutting of test pieces according to the requirements specified in
8.2.
5.2.1 Band-saw or knife and cutting jig to prepare the test pieces. The equipment shall produce cut
edges that are unfrayed, straight and perpendicular to the facings of the board.
5.2.2 Circular saw, equipped with a sharp, no-set (hollow-ground or taper-ground is desirable) saw
blade. Ensure that the saw blade is 90° to the table supporting the test piece.
5.2.3 Motorized dual-knife-type cutter with flat, straight, parallel and freshly sharpened blades
which should be approximately 0,5 mm thick, sharpened on one side only to a bevel of about 3 mm and
mounted so that the plane sides of the blades face each other (i.e. inwards) and are perpendicular to the
faces of the board. The blades of such a cutter must be kept in good alignment.
It is recommended that the blades of this type of cutter be replaced after being used more than
100 times.
5.2.4 Other types of test-piece cutters, such as a manual knife used with a guide, can be employed
provided it can be shown that they meet the requirements specified in 8.2.
5.3 Guide blocks, consisting of two rectangular, smooth-finished, metal (or wood) blocks of cross-
section dimensions 40 mm × 20 mm, and at least 40 mm in length, to support the test piece and keep
it perpendicular to the platens. The blocks are cut back by 2 mm, as shown in Figure 1, to avoid contact
with the waxed areas.
5.4 Molten paraffin, with a melting point of approximately 52 °C.
Dimensions in millimetres
Figure 1 — Guide block
6 Sampling
The specimens, taken in accordance with ISO 186, shall permit the preparation of test pieces free from
converting machine marks. If the test specimens are to be taken from corrugated shipping containers,
they should be taken from areas away from score lines, joints, and closures. Specimens should be
representative of the materials being tested. For example, if roughly 25 % of a box is printed, roughly
25 % of the specimens should be collected from the printed areas. Specimens should not be taken from
obviously damaged areas and/or areas not representative of the container as a whole.
2 © ISO 2020 – All rights reserved

7 Conditioning
Condition the sample in accordance with ISO 187.
8 Preparation of test pieces
8.1 Gener
...

INTERNATIONAL ISO
STANDARD 13821
Second edition
2020-06
Corrugated fibreboard —
Determination of edgewise crush
resistance — Waxed edge method
Carton ondulé — Détermination de la résistance à la compression sur
chant — Méthode du bord paraffiné
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus and test liquid . 1
6 Sampling . 2
7 Conditioning . 3
8 Preparation of test pieces . 3
8.1 General . 3
8.2 Cutting the test pieces . 3
8.3 Waxing . 3
9 Procedure. 4
10 Calculation . 4
11 Precision . 4
11.1 General . 4
11.2 Precision data from TAPPI-CTS . 5
12 Test report . 5
Bibliography . 6
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 6/SC 2, Test methods and quality
specifications for paper and board.
This second edition cancels and replaces the first edition (ISO 13821:2002), of which it constitutes a
minor revision.
The main changes compared to the previous edition are as follows:
— Introduction of an additional group in the Introduction clause;
— Information on sampling of corrugated shipping containers are added in Clause 6;
— Information in 8.2 on the height of the test pieces;
— Introduction of precision data based on TAPPI comparative testing service.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

Introduction
A variety of methods for the determination of edgewise crush resistance are in use in different parts of
the world. These can be classified into four groups as follows:
a) Those in which a carefully cut rectangular test piece is tested without any special treatment or
modification.
b) Those in which the edges of the test piece to which the force is applied are waxed to prevent the
test result from being influenced by “edge effects”.
c) Those in which the test piece edges are not waxed but the shape of the test piece is such that the
length is substantially reduced at a point midway between the loading edges in order to induce the
failure to occur away from those edges.
d) Those in which carefully cut rectangular pieces are tested with edges clamped to prevent the test
result from being influenced by "edge effects".
The dimensions of the test piece vary from one group to the other and, in group c), the methods vary
according to the shape and method of reducing the length.
The methods may not give the same numerical results, but it can be shown that most of them can be
used to predict the top-to-bottom compression strength which will be achieved when the board is
properly converted into a transport package.
This document describes a method from group b) intended to be used for quality measurement and
quality specification purposes. This particular method is selected because it correlates well with the
top-to-bottom compression strength of the final transport package and provides significantly higher
results than unwaxed methods (a) because edge effects are avoided.
INTERNATIONAL STANDARD ISO 13821:2020(E)
Corrugated fibreboard — Determination of edgewise crush
resistance — Waxed edge method
1 Scope
This document specifies a method for the determination of the edgewise crush resistance of corrugated
fibreboard. The force is applied in the direction of the flute axis.
This method is applicable to single-wall (double-faced), double-wall, and triple-wall corrugated
fibreboard. It may also be used to test samples taken from corrugated cases and other converted
products.
While the method is applicable to waxed corrugated fibreboard, care must be taken that the heat used
in the waxing step does not affect the corrugated structure. This is controlled by observing that failure
during the test still occurs away from the loaded edges.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 186, Paper and board — Sampling to determine average quality
ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
ISO 13820, Paper, board and corrugated fibreboard — Description and calibration of compression-testing
equipment
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
Subjection of a rectangular test piece of corrugated board placed between the platens of a crush tester,
with the flutes perpendicular to the platens, to a compressive force until failure occurs. The loading
edges of the test piece have been reinforced by paraffin to prevent premature failure at those edges
when the load is applied.
Measurement of the maximum force sustained by the test piece.
5 Apparatus and test liquid
5.1 Motor-driven, platen-type compression testing machine. The apparatus described in ISO 13820
shall be used.
5.2 Cutting equipment, enabling the cutting of test pieces according to the requirements specified in
8.2.
5.2.1 Band-saw or knife and cutting jig to prepare the test pieces. The equipment shall produce cut
edges that are unfrayed, straight and perpendicular to the facings of the board.
5.2.2 Circular saw, equipped with a sharp, no-set (hollow-ground or taper-ground is desirable) saw
blade. Ensure that the saw blade is 90° to the table supporting the test piece.
5.2.3 Motorized dual-knife-type cutter with flat, straight, parallel and freshly sharpened blades
which should be approximately 0,5 mm thick, sharpened on one side only to a bevel of about 3 mm and
mounted so that the plane sides of the blades face each other (i.e. inwards) and are perpendicular to the
faces of the board. The blades of such a cutter must be kept in good alignment.
It is recommended that the blades of this type of cutter be replaced after being used more than
100 times.
5.2.4 Other types of test-piece cutters, such as a manual knife used with a guide, can be employed
provided it can be shown that they meet the requirements specified in 8.2.
5.3 Guide blocks, consisting of two rectangular, smooth-finished, metal (or wood) blocks of cross-
section dimensions 40 mm × 20 mm, and at least 40 mm in length, to support the test piece and keep
it perpendicular to the platens. The blocks are cut back by 2 mm, as shown in Figure 1, to avoid contact
with the waxed areas.
5.4 Molten paraffin, with a melting point of approximately 52 °C.
Dimensions in millimetres
Figure 1 — Guide block
6 Sampling
The specimens, taken in accordance with ISO 186, shall permit the preparation of test pieces free from
converting machine marks. If the test specimens are to be taken from corrugated shipping containers,
they should be taken from areas away from score lines, joints, and closures. Specimens should be
representative of the materials being tested. For example, if roughly 25 % of a box is printed, roughly
25 % of the specimens should be collected from the printed areas. Specimens should not be taken from
obviously damaged areas and/or areas not representative of the container as a whole.
2 © ISO 2020 – All rights reserved

7 Conditioning
Condition the sample in accordance with ISO 187.
8 Preparation of test pieces
8.1 Gener
...