ISO 1288-3:2016
(Main)Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen supported at two points (four point bending)
Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen supported at two points (four point bending)
ISO 1288-3:2016 specifies a method for determining the bending strength, including the effects of the edges, of flat glass for use in building. The method specified can also be used to determine the bending strength of the edges of glass separately. The limitations of this part of ISO 1288 are described in ISO 1288‑1.
Verre dans la construction — Détermination de la résistance du verre à la flexion — Partie 3: Essais avec éprouvettes supportées en deux points (flexion quatre points)
General Information
- Status
- Published
- Publication Date
- 15-Feb-2016
- Technical Committee
- ISO/TC 160/SC 2 - Use considerations
- Drafting Committee
- ISO/TC 160/SC 2/WG 1 - Design strength of glazing
- Current Stage
- 9093 - International Standard confirmed
- Start Date
- 12-Oct-2021
- Completion Date
- 13-Dec-2025
Relations
- Effective Date
- 06-Jun-2022
Overview
ISO 1288-3:2016 - Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen supported at two points (four point bending) specifies a laboratory method to determine the bending strength of flat glass used in buildings, including the influence of edge condition. The standard defines test geometry, apparatus, environmental conditions and evaluation rules for four‑point bending tests. Limitations and fundamental principles are covered in ISO 1288‑1.
Key topics and technical requirements
- Test method: Four‑point bending with the specimen supported on two rollers and loaded by two bending rollers (see standard figures).
- Specimen dimensions: nominal length 1 100 mm ±5 mm; width 360 mm ±5 mm; thickness per supplied tolerance.
- Apparatus: testing machine with stepless loading, load measurement accuracy ±2.0%, free‑rotating rollers of 50 mm diameter and ≥365 mm length; rubber strips between rollers and specimen.
- Rubber strips: 3 mm thick, hardness (40 ± 10) IRHD (ISO 48).
- Environmental conditions: test at (23 ± 5) °C and 40–70% relative humidity; temperature held constant to 1 °C during test.
- Loading rate: increase bending stress uniformly at (2 ± 0,4) MPa/s until failure; record maximum force Fmax and time to failure.
- Measurements: specimen width (to nearest 1 mm) and thickness (measured at multiple points; instruments specified for high resolution - see clauses 5.2 and 7.1). Adhesive film is applied to the tensile side to retain fragments and locate fracture origin.
- Evaluation: bending strength σb is calculated from Fmax, specimen geometry and a dimensionless factor k (k depends on central deflection y/h - ISO provides the relation and curves). Self‑weight correction σbG is included where relevant. Only fractures originating between bending rollers are used for surface strength; special rules apply for edge strength statistics.
- Reporting: mandatory items include reference to ISO 1288‑3, glass type, edge finish, pre‑treatment, number of specimens, individual thickness/width, bending or edge strength per specimen, time to breakage, and whether break originated at the edge or body.
Applications and users
ISO 1288-3 is used by:
- Glass manufacturers for product development and quality control.
- Independent testing laboratories for type approval and certification.
- Façade and structural engineers, architects to verify design values for flat glass elements and to assess edge workmanship effects.
- Regulatory bodies and product certifiers needing standardized strength data for safety and compliance.
Practical value: provides repeatable, comparable bending strength data (including edge effects) for structural glass design, fracture analysis and quality assurance.
Related standards
- ISO 1288‑1 (Fundamentals of testing glass)
- Other parts of ISO 1288 (Parts 2, 4, 5)
- ISO 48 (Rubber hardness)
- ISO 16293‑1 (Young’s modulus reference for soda‑lime silicate glass)
Keywords: ISO 1288-3:2016, four point bending, bending strength of glass, edge strength, glass testing, flat glass, building glazing standards.
ISO 1288-3:2016 - Glass in building -- Determination of the bending strength of glass
ISO 1288-3:2016 - Glass in building -- Determination of the bending strength of glass
Frequently Asked Questions
ISO 1288-3:2016 is a standard published by the International Organization for Standardization (ISO). Its full title is "Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen supported at two points (four point bending)". This standard covers: ISO 1288-3:2016 specifies a method for determining the bending strength, including the effects of the edges, of flat glass for use in building. The method specified can also be used to determine the bending strength of the edges of glass separately. The limitations of this part of ISO 1288 are described in ISO 1288‑1.
ISO 1288-3:2016 specifies a method for determining the bending strength, including the effects of the edges, of flat glass for use in building. The method specified can also be used to determine the bending strength of the edges of glass separately. The limitations of this part of ISO 1288 are described in ISO 1288‑1.
ISO 1288-3:2016 is classified under the following ICS (International Classification for Standards) categories: 81.040.20 - Glass in building. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 1288-3:2016 has the following relationships with other standards: It is inter standard links to ISO/IEC 17344:2005. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ISO 1288-3:2016 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 1288-3
First edition
Glass in building — Determination of
the bending strength of glass —
Part 3:
Test with specimen supported at two
points (four point bending)
Verre dans la construction — Détermination de la résistance du verre
à la flexion —
Partie 3: Essais avec éprouvettes supportées en deux points (flexion
quatre points)
PROOF/ÉPREUVE
Reference number
ISO 1288-3:2015(E)
©
ISO 2015
ISO 1288-3:2015(E)
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved
ISO 1288-3:2015(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Apparatus . 2
5.1 Testing machine . 2
5.2 Measuring instruments . 3
6 Sample . 3
6.1 Number of specimens . 3
6.2 Specimen dimensions . 3
6.3 Specimen condition and treatment . 3
6.4 Adhesive film . 4
7 Procedure. 4
7.1 Measuring width and thickness of each specimen . 4
7.2 Bending test . 4
8 Evaluation . 5
8.1 General . 5
8.2 Bending strength of the surface area, edges included . 5
8.3 Bending strength of the edges . 5
9 Test report . 6
Bibliography . 8
ISO 1288-3:2015(E)
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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 160, Glass in building, Subcommittee SC 2, Use
considerations.
ISO 1288 consists of the following parts, under the general title Glass in building — Determination of the
bending strength of glass:
— Part 1: Fundamentals of testing glass
— Part 2: Coaxial double ring test on flat specimens with large test surface areas
— Part 3: Test with specimen supported at two points (four point bending)
— Part 4: Testing of channel shaped glass
— Part 5: Coaxial double ring test on flat specimens with small test surface areas
iv PROOF/ÉPREUVE © ISO 2015 – All rights reserved
INTERNATIONAL STANDARD ISO 1288-3:2015(E)
Glass in building — Determination of the bending
strength of glass —
Part 3:
Test with specimen supported at two points (four point
bending)
1 Scope
This part of ISO 1288 specifies a method for determining the bending strength, including the effects
of the edges, of flat glass for use in building. The method specified can also be used to determine the
bending strength of the edges of glass separately.
The limitations of this part of ISO 1288 are described in ISO 1288-1.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 48, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD
and 100 IRHD)
1)
ISO 1288-1 , Glass in building — Determination of the bending strength of glass — Part 1: Fundamentals
of testing glass
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bending stress
tensile bending stress induced in the surface of a specimen
Note 1 to entry: For testing purposes, the bending stress should be uniform over a specified part of the surface.
3.2
effective bending stress
weighted average of the tensile bending stresses, calculated by applying a factor to take into account
non-uniformity of the stress field
3.3
bending strength
bending stress or effective bending stress which leads to breakage of the specimen
3.4
equivalent bending strength
apparent bending strength of patterned glass, for which the irregularities in the thickness do not allow
precise calculation of the bending stress
1) To be published.
...
INTERNATIONAL ISO
STANDARD 1288-3
First edition
2016-02-15
Glass in building — Determination of
the bending strength of glass —
Part 3:
Test with specimen supported at two
points (four point bending)
Verre dans la construction — Détermination de la résistance du verre
à la flexion —
Partie 3: Essais avec éprouvettes supportées en deux points (flexion
quatre points)
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Apparatus . 2
5.1 Testing machine . 2
5.2 Measuring instruments . 3
6 Sample . 3
6.1 Number of specimens . 3
6.2 Specimen dimensions . 3
6.3 Specimen condition and treatment . 3
6.4 Adhesive film . 4
7 Procedure. 4
7.1 Measuring width and thickness of each specimen . 4
7.2 Bending test . 4
8 Evaluation . 5
8.1 General . 5
8.2 Bending strength of the surface area, edges included . 5
8.3 Bending strength of the edges . 5
9 Test report . 6
Bibliography . 8
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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 160, Glass in building, Subcommittee SC 2, Use
considerations.
ISO 1288 consists of the following parts, under the general title Glass in building — Determination of the
bending strength of glass:
— Part 1: Fundamentals of testing glass
— Part 2: Coaxial double ring test on flat specimens with large test surface areas
— Part 3: Test with specimen supported at two points (four point bending)
— Part 4: Testing of channel shaped glass
— Part 5: Coaxial double ring test on flat specimens with small test surface areas
iv © ISO 2016 – All rights reserved
INTERNATIONAL STANDARD ISO 1288-3:2016(E)
Glass in building — Determination of the bending
strength of glass —
Part 3:
Test with specimen supported at two points (four point
bending)
1 Scope
This part of ISO 1288 specifies a method for determining the bending strength, including the effects
of the edges, of flat glass for use in building. The method specified can also be used to determine the
bending strength of the edges of glass separately.
The limitations of this part of ISO 1288 are described in ISO 1288-1.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 48, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD
and 100 IRHD)
ISO 1288-1, Glass in building — Determination of the bending strength of glass — Part 1: Fundamentals of
testing glass
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bending stress
tensile bending stress induced in the surface of a specimen
Note 1 to entry: For testing purposes, the bending stress should be uniform over a specified part of the surface.
3.2
effective bending stress
weighted average of the tensile bending stresses, calculated by applying a factor to take into account
non-uniformity of the stress field
3.3
bending strength
bending stress or effective bending stress which leads to breakage of the specimen
3.4
equivalent bending strength
apparent bending strength of patterned glass, for which the irregularities in the thickness do not allow
precise calculation of the bending str
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