ISO 20492-4:2010

INTERNATIONAL ISO
STANDARD 20492-4
First edition
2010-08-15
Glass in buildings — Insulating glass —
Part 4:
Methods of test for the physical attributes
of edge seals
Verre dans la construction — Verre isolant —
Partie 4: Méthodes d'essai pour les caractéristiques physiques des
joints d'assemblage
Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms, definitions and symbols .1
3.1 Terms and definitions .1
3.2 Symbols.2
4 Requirements.2
4.1 Edge seal strength .2
4.2 Compliance with the definition of insulating glass units.3
5 Test methods .4
5.1 Adhesion .4
5.2 Moisture vapour transmission rate .6
5.3 Gas permeation test on film .7
6 Test report.8
Annex A (normative) Test specimens for adhesion test .10
Annex B (normative) Requirement for edge seal strength comparisons in case of substituting
sealant .13
Annex C (normative) Method of measuring the moisture vapour transmission rate .14
Annex D (normative) Adhesion on coatings and interlayer adhesion of coatings.17
Annex E (normative) Informative tests .22
Annex F (informative) Example of a sun-simulating radiation source .23
Bibliography.24

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 20492-4 was prepared by Technical Committee ISO/TC 160, Glass in building, Subcommittee SC 1,
Product considerations.
ISO 20492 consists of the following parts, under the general title Glass in buildings — Insulating glass:
⎯ Part 1: Durability of edge seals by climate tests
⎯ Part 2: Chemical fogging tests
⎯ Part 3: Gas concentration and gas leakage
⎯ Part 4: Methods of test for the physical attributes of edge seals
iv © ISO 2010 – All rights reserved

Introduction
This International Standard consists of a series of procedures for testing the performance of pre-assembled,
permanently sealed insulating glass units or insulating glass units with capillary tubes that have been
intentionally left open. This International Standard is intended to help ensure that
⎯ energy savings are made, as the U value and solar factor (solar heat gain coefficient) do not change
significantly;
⎯ health is preserved, because sound reduction and vision do not change significantly;
⎯ safety is provided because mechanical resistance does not change significantly.
This International Standard also covers additional characteristics that are important to the trade, and marking
of the product (i.e. CE marking or other regulatory groups).
There are distinct markets to consider for insulating glass. Within each market there are technical differences
with respect to rebate sizes, vision lines and methods of application; two approaches are included in this
International Standard. Approach 1 addresses requirements for markets such as North America. Approach 2
addresses requirements for markets such as Europe. Each approach includes separate test methods and
specifications pertaining to minimum requirements for durability of edge seals by climate tests.
This International Standard does not cover physical requirements of sealed glass insulating units such as
appearance, thermo-physical properties, heat and light transmission, and glass displacement.
The main intended uses of the insulating glass units are installations in buildings and constructions such as in
windows, doors, curtain walling, skylights, roofs and partitions where protection against direct ultraviolet
radiation exists at the edges.
The use of insulating glass in cases where there is no protection against direct ultraviolet radiation at the
edges, such as structural glazing systems, can be suitable. However, it can be necessary to review factors
such as sealant longevity when exposed to long-term ultraviolet light and the structural properties of the
sealant for these applications.
NOTE 1 For more information on the requirements for structural sealant glazing applications, reference can be made to
ASTM C1369, ASTM C1249 and ASTM C1265 and CEN technical specifications.
NOTE 2 IG units whose function is artistic only are not part of this International Standard.
The test methods in this International Standard are intended to provide a means for testing the performance of
the sealing system and construction of sealed insulating glass units.
Sealed insulating glass units tested in accordance with these methods are not intended for long-term
immersion in water.
The options for testing apply only to sealed insulating glass units that are constructed with glass.
In certain cases such as insulating glass units containing spandrel glass or absorptive coatings, these
methods might not be applicable, as these products can experience field temperatures that exceed the
temperature limitations of the sealant.

INTERNATIONAL STANDARD ISO 20492-4:2010(E)

Glass in buildings — Insulating glass —
Part 4:
Methods of test for the physical attributes of edge seals
1 Scope
This part of ISO 20492 specifies methods for testing the edge seal strength, and partially testing the moisture
and gas permeation through sealants, of glass insulating units. Other parts of ISO 20492 designate two
approaches to the standardization of insulating glass units: approach 1 is intended for use in markets such as
North America; and approach 2 is intended for use in markets such as Europe.
The methods in this part of ISO 20492 are applicable only to approach 2, as defined and used in the other
parts of ISO 20492.
In cases where there is no protection against direct ultraviolet radiation at the edges, such as structural
sealant glazing systems, it is necessary that additional European technical specifications be followed. See
References [4] and [5].
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.
ISO 20492-1, Glass in building — Insulating glass — Part 1: Durability of edge seals by climate tests
ISO 20492-3, Glass in building — Insulating glass — Part 3: Gas concentration and gas leakage
ISO 9050, Glass in building — Determination of light transmittance, solar direct transmittance, total solar
energy transmittance, ultraviolet transmittance and related glazing factors
EN 1096 (all parts), Glass in building — Coated glass
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 20492-1 and the following apply.
3.1.1
moisture vapour transmission rate
steady moisture vapour flow in unit time through unit area of a body, normal to specific parallel surfaces,
under specific conditions of temperature and humidity at each surface
3.1.2
standard room conditions
ambient temperature of (23 ± 2) °C and a relative humidity of (50 ± 5) % relative humidity
3.2 Symbols
For the purpose of this document, the symbols given in ISO 20492-1 and the following apply.
ε extension of bond expressed as a percent
σ stress applied to the bond during extension
θ moisture vapour transmission rate
∆P difference in water vapour pressure across a membrane
H O
4 Requirements
4.1 Edge seal strength
All edge seals shall have sufficient adhesive and cohesive strength to allow the extension of seals such that
any rupture of the seal occurs outside the area 0AB of Figure 1.
If, during the strength test of the glass-sealant-glass joint, as seen from the side view, loss of adhesion or
cohesion extends through the whole depth of the sealant within the area 0AB of Figure 1, then the sealant test
specimen has failed (see Figure 2). The principle of light transmission through the defect can be applied to
determine pass or failure.
Breakage of the glass during testing does not constitute failure, providing that a sufficient number of joints is
tested in order that a successful average result can be obtained.
For comparisons of the seal strength required for substituting sealants, see Annex B.

Key
X strain in the sealant, ε
Y stress in the sealant, σ
a
No breakage is allowed before and after ageing in area 0AB.
Figure 1 — Stress/strain triangle
2 © ISO 2010 – All rights reserved

Key
1 loss of cohesion
2 loss of adhesion
Figure 2 — Illustration of the extension of loss of adhesion
or cohesion through the whole depth
4.2 Compliance with the definition of insulating glass units
4.2.1 General
A test report shall be available of the concerned insulating glass outer sealant according to Clause 6 (which
summarizes the test report in which the edge seal strength is recorded) with a moisture penetration test report
in accordance with ISO 20492-1 and, in case of gas-filled units, also with a gas leakage rate report in
accordance with ISO 20492-3, and fulfils the requirement to demonstrate the conformity with the definition of
insulating glass units.
In the case of sealing the insulating glass unit with a coating that is not intended to be stripped in accordance
with
...