ISO 20492-4:2010
(Main)Glass in buildings — Insulating glass — Part 4: Methods of test for the physical attributes of edge seals
Glass in buildings — Insulating glass — Part 4: Methods of test for the physical attributes of edge seals
ISO 20492-4:2010 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 ISO 20492-4:2010 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.
Verre dans la construction — Verre isolant — Partie 4: Méthodes d'essai pour les caractéristiques physiques des joints d'assemblage
General Information
Standards Content (Sample)
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 20492-4:2010(E)
©
ISO 2010
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ISO 20492-4:2010(E)
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ISO 20492-4:2010(E)
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
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ISO 20492-4:2010(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.
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
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ISO 20492-4:2010(E)
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.
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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
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ISO 20492-4:2010(E)
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
2
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
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ISO 20492-4:2010(E)
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 EN 1096 (all parts), a test report in accordance with Annex D shall be made available for inclusion in with
the other test reports.
NOTE Although only clear float glass is referred to in this part of ISO 10492, it is the responsibility of the insulating
glass manufacturer to ensure that the edge sealant is capable of bonding to all glasses that are used. The requirements
for the use of coated glasses in accordance with EN 1096 (all parts) are detailed in Annex D.
4.2.2 Possibility to substitute the sealant
4.2.2.1 Limits of application
The possibility of substituting for the sealant is applicable only in the case of insulating glass units with a
hollow metal spacer. For other systems, no experience is available for setting up the substitution rules.
4.2.2.2 Air-filled insulating glass units
Available test reports in accordance with Clause 6 allow for the substitution of the sealant without repeated
moisture penetration testing in accordance with ISO 20492-1 in the following cases.
a) For units with an I value below 0,1, the substituting sealant
⎯ shall be applicable with the same production equipment,
⎯ has been previously applied in insulating glass units that have been demonstrated to comply with
ISO 20492-1; the demonstrated compliance may have been obtained separately using units of
different construction and, therefore, the test report numbers may vary,
⎯ has a moisture vapour transmission rate that is not more than 20 % higher than that of the initial
sealant,
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ISO 20492-4:2010(E)
⎯ has a stress/strain curve comparison that satisfies the requirement in Annex B,
⎯ shall have the relevant parts of the factory production control (periodic test, mixing ratio, hardness
test, etc.) carried out.
b) For units with an I value between 0,1 and 0,2, the list under a) applies however with the exception that the
moisture vapour transmission rate through membrane of the substitute sealant shall be the same or lower
than the initial sealant.
4.2.2.3 Gas-filled insulating glass units
Available test reports in accordance with Clause 6 allow the substitution of the sealant without repeated gas
loss rate testing according to ISO 20492-3 in the following cases.
−1
a) For units with a gas loss rate, L , below 0,8 % a , the substituting sealant
i
⎯ is allowed for limiting the moisture vapour penetration in accordance with 4.2.2.2,
⎯ has been previously applied in insulating glass units that have been demonstrated to comply with
ISO 20492-3; the demonstrated compliance may have been obtained separately using units of
different construction and, therefore, the test report numbers may vary,
⎯ has a gas permeation that is not more than 20 % higher than that of the initial sealant.
−1 −1
For units with a gas loss rate, L , between 0,8 % a and 1,0 % a , the list under a) applies, however with the
i
exception that the gas permeation of the substitute sealant shall be the same or lower than the initial sealant.
4.2.3 Possibility of substitute the coated glass, coatings not intended to be removed
Available test reports in accordance with Annex D allow for the substitution of the coated glasses in
accordance with EN 1096 (all parts) when the coating is not intended to be stripped from the area where the
insulating glass is sealed without repeated moisture penetration testing according to ISO 20492-1 and, in case
of gas-filled units, without repeated gas loss rate testing in accordance with ISO 20492-3, when the provisions
set out in Annex D are followed.
5 Test methods
5.1 Adhesion
5.1.1 Principle
The test consists of preparing a number of glass-sealant-glass joints, some of which are unaged and some
are subjecting to ageing regimes as outlined in 5.1.3 before testing under tensile load.
The test specimen shapes and bond preparations shall be as specified in Annex A. For insulating glass units
with systems that cannot apply Annex A, the test specimen shall be 50 mm cut from the edge seal of an
insulating glass unit. The shape of the samples shall be as similar as possible. Their cross-sections shall have
a cross-section as near as possible to the test specimen described in Annex A. The number of joints is seven
per exposure condition.
After manufacturing, ageing where relevant and conditioning for 24 h to 48 h at standard room conditions, the
test specimens shall be measured accurately for width, depth and height prior to being placed in an
extensiometer with an accuracy equal to or better than 2 %.
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ISO 20492-4:2010(E)
Manufacturing test specimen
by manufacturer or by
laboratory
At last 21 days : curing at standard room conditions
When necessary to transport from manufacturing site to test site
days at least: conditioning at standard room conditions
Ageing
24h to 48h: conditioning at standard room conditions
Tensile tests
Calculation and presentation
of test results
Figure 3 — Schematic presentation of test order for adhesion — Flow from top to bottom
The speed of separation is in case of polymer-based edge sealants (5 ± 0,25) mm/min, and in case of metallic
edge seals (12,5 ± 0,5) mm/min. See Figure 3 for the schematic presentation of the order of the preparation
and tests.
Where the glass continuously breaks, a bond stiffener can be bonded to the glass immediately prior to testing
but after ageing. Stiffening can be accomplished by the addition of a second piece of glass or other material
bonded, for example, with a cyanoacrylate adhesive.
5.1.2 Calculation of stress and expression of results
The stresses are calculated from the mean of the contact areas between the sealant and the glass in one test
2
specimen. In case of metal seal, the contact area is fixed on 100 mm (see Figure A.2).
The results are expressed as the average values of the stress and strain when the stress/strain curves cross
the line AB of Figure 1. The highest and lowest values are ignored so that the average values are calculated
on the five remaining measured stress and strain values.
5.1.3 Procedures
5.1.3.1 Initial cure test
After initial cure (see Annex A) and conditioning at standard room conditions of at least seven days, seven test
specimens not subjected to any ageing regime are subjected to tensile load.
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ISO 20492-4:2010(E)
5.1.3.2 Heat exposure
After initial cure and conditioning at standard room conditions of at least seven days, the seven test
specimens for heat ageing shall be aged in a closed oven at (60 ± 2) °C for (168 ± 5) h. Where the sealant
shows plastic flow at 60 °C, the spacers shall be retained between the two glass pieces to prevent bond
deformation.
5.1.3.3 Water immersion
After initial cure and conditioning at standard room conditions of at least seven days, all seven test specimens
for water immersion shall be immersed in 1 l to 2 l of distilled or deionized water for (168 ± 5) h, at standard
room condition. Fresh new water shall be used for each test. The conductance of the fresh water shall be
equal to or less than 30 µS.
5.1.3.4 UV exposure
After initial cure and conditioning at standard room conditions of at least seven days, seven test specimens for
UV exposure shall be subject (96 ± 4) h to UV irradiation, which shall be perpendicular to the glass at an
2
intensity in the UVA range in accordance with ISO 9050 of (40 ± 5) W/m . Refer to Figure 3 for the radiation
orientation and to Annex F for an example of a UV radiation source.
The height of the UV source shall be adjusted to ensure all joint assemblies are subjected to the minimum
intensity.
The irradiation intensity shall be measured at the beginning and end of each test. When the minimum
irradiation can no longer be achieved, a new UV source shall be installed.
Key
1 clear float glass
2 tested surface, which can be coated
3 ultraviolet radiation
Figure 4 — Orientation of the surface being tested to the ultraviolet radiation
5.2 Moisture vapour transmission rate
5.2.1 General
The information on the moisture vapour transmission rate is requested only when sealant comparisons are
made for the purpose of change.
5.2.2 Principle
The moisture vapour transmission rate, θ, when determined, shall be measured on a 2 mm thick film as
outlined in 5.2.3.
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ISO 20492-4:2010(E)
5.2.3 Procedure
5.2.3.1 Film preparation
It is advisable to prepare films from the dispensing machines used by the insulating glass unit manufacturer.
Hand mixing or small-scale heating, where appropriate, can give erratic results.
5.2.3.2 Applicable tests
There is a wide variety of tests for moisture vapour transmission rates. They vary by film thickness, ∆P
H O
2
across the film and temperature of test.
For comparison, the method defined in the Annex C shall be used with the following criteria.
⎯ Film thickness shall be (2 ± 0,1) mm.
⎯ Test temperature shall be (23 ± 1) °C.
⎯ ∆P shall be from equal or less than 5 % (desiccant) to equal or more than 90 % relative humidity (test
H O
2
chamber) across the membrane.
5.3 Gas permeation test on film
5.3.1 General
The information on the gas permeation is requested only when sealant comparisons are made for the purpose
of change.
5.3.2 Principle
This test is not relevant where the sealant manufacturer clearly states that the sealant is not intended for use
in gas-filled insulating glass units.
The gas permeation rate, when determined, shall be measured on a 2 mm thick film as outlined in 5.3.3.
5.3.3 Procedures
The gas permeation test shall be carried out using similar apparatus and the same test conditions as those
specified in ISO 20492-3. A gas cell shall be introduced in place of the test unit in the line using the film as a
membrane. Argon gas shall be used as a test gas. A pressure not exceeding 10 mbar shall be applied to the
test gas side of the film. Helium gas shall be used as carrier gas.
2
The area shall be recorded and shall not be less than 10 cm . The shape can be circular as well as square,
and shall be recorded. The value of the gas permeation, expressed in grams per square metre per hour,
through the film shall be determined when a steady state condition is achieved.
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ISO 20492-4:2010(E)
6 Test report
The test report shall evaluate the test in detail and shall include the information shown in Figure 5.
Name of the test house, its address and logo
Summary of report No. . Date .
Insulating glass — Seal properties results in accordance with ISO 20492-4
For details, see the test report
Company: Name: .
Address: .
....................................................................................................................
....................................................................................................................
Plant: Name: .
Address: .
....................................................................................................................
....................................................................................................................
Sealant specification: .
Sealant in IGU positively tested in accordance with ISO 20492-1, report No.: .
Glass specification when float glass is not used: .
Seal strength test At intersection with line A-B (ISO 20492-4, Figure 1): Type of failure
observed (if any)
Adhesion: Average stress σ Average extension ε C = cohesive A = adhesive
av av
in MPa in % 1 2 3 4 5
Initial cure
After water immersion
After heating 60 °C
After UV radiation
NOTE It is recommended to include the stress/strain curves (informative test E.1) with this report.
Figure 5 (continued)
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ISO 20492-4:2010(E)
Moisture vapour transmission rate (when applicable for substituting sealant):
Film thickness . mm
∆P . % relative humidity difference across the membrane
H O
2
Temperature . °C
−2
θ . grams per H O⋅m per 24 h
2
Gas permeation rate (when applicable for substituting sealant and when sealant serves for gas-filled insulating glass units):
Film thickness . mm
2
Surface: . m - Shape: circular/square (delete whichever is not applicable)
−2 −1
Permeation rate: . g·m ⋅h
Overall comments (when applicable, use a separate sheet):
Conclusion of seal strength test:
The sealant conforms to the test criteria: YES NO (delete whichever is not applicable)
..................................
Name and signature
Figure 5 — Test report for the physical attributes of edge seals
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ISO 20492-4:2010(E)
Annex A
(normative)
Test specimens for adhesion test
A.1 Polymer based edge sealants
The test specimens consist of preparing a number of glass-sealant-glass joints (see Figure A.1) as follows:
⎯ glass size: 75 mm × 12 mm × 6 mm;
⎯ sealant size: 50 mm × 12 mm × 12 mm.
Dimensions in millimetres
Tolerances on the dimensions of the sealant ±1 mm
Key
1 glass
2 sealant
3 face that may be coated
Figure A.1 — A polymer-based edge sealant test specimen
After the glass is cut to the desired dimensions, it should be thoroughly cleaned and dried before being used
in the test specimen. The cleaning process can be similar to that used by the insulating glass manufacturer
and, when necessary precautions are taken, the bonds may be prepared in the factory of the insulating glass
unit manufacturer.
Other cleaning processes are allowed providing that the process does not interfere with the adhesive qualities
of the sealant either positively or negatively, by chemically modifying the glass surface.
After cleaning the glass, the test specimen shall be prepared from freshly mixed (in case of two part sealan
...
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