ISO 20492-2:2008
(Main)Glass in buildings - Insulating glass — Part 2: Chemical fogging tests
Glass in buildings - Insulating glass — Part 2: Chemical fogging tests
ISO 20492:2008 establishes two methods for testing the resistance to fogging of pre-assembled, permanently sealed insulating glass units or insulating glass units with capillary tubes intentionally left open. The two methods are designated as approach 1 for markets such as North America, and approach 2 for markets such as Europe. ISO 20492:2008 is not applicable to sealed, insulating glass units containing a spandrel glass coating due to testing limitations. ISO 20492:2008 does not apply to insulating glass (IG) units whose function is decorative only.
Verre dans la construction — Verre isolant — Partie 2: Essais d'embuage chimique
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 20492-2
First edition
2008-10-01
Glass in buildings — Insulating glass —
Part 2:
Chemical fogging tests
Verre dans la construction — Verre isolant —
Partie 2: Essais d'embuage chimique
Reference number
©
ISO 2008
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ii © ISO 2008 – All rights reserved
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Requirements.2
5 Test methods .2
6 Test report.8
Bibliography.13
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
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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 20492-2 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: Test methods for the physical attributes of edge seals
iv © ISO 2008 – All rights reserved
Introduction
This part of ISO 20492 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 part of ISO 20492 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 part of ISO 20492 also covers additional characteristics that are important to the trade, and marking of
the product (i.e. CE marking or other regulatory groups) is also included.
There are distinct markets to be considered for insulating glass. As within each market there are technical
differences with respect to rebate sizes, vision lines and methods of application, two approaches are included
in this part of ISO 20492. 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 the durability of edge seals by climate
tests.
This part of ISO 20492 does not cover the 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.
NOTE In cases where there is no protection against direct ultraviolet radiation at the edges, such as structural-
sealant glazing systems, it is still 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. For more information on the requirements
[1] [2]
for structural sealant glazing applications, reference can be made to ASTM C1369 , ASTM C1249 and
[3]
ASTM C1265 .
The test methods in this part of ISO 20492 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.
The methods of this part of ISO 20492 might not be applicable in certain cases, such as insulating glass units
containing spandrel glass or absorptive coatings, as these products can experience field temperatures that
exceed the temperature limitations of the sealant.
INTERNATIONAL STANDARD ISO 20492-2:2008(E)
Glass in buildings — Insulating glass —
Part 2:
Chemical fogging tests
1 Scope
This part of ISO 20492 establishes two methods for testing the resistance to fogging of pre-assembled,
permanently sealed insulating glass units or insulating glass units with capillary tubes intentionally left open.
The two methods are designated as Approach 1 for markets such as North America, and Approach 2 for
markets such as Europe.
This part of ISO 20492 is not applicable to sealed, insulating glass units containing a spandrel glass coating
due to testing limitations.
This part of ISO 20492 does not apply to insulating glass (IG) units whose function is decorative only.
2 Normative references
The following reference documents are indispensable for the application of this document. For dated
references, only the cited edition applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 20492-1, Glass in buildings — Insulating glass — Part 1: Durability of edge seals by climate tests
EN 572-1, Glass in building — Basic soda lime silicate glass products — Definitions and general physical and
mechanical properties
EN 572-2, Glass in building — Basic soda lime silicate glass products — Float glass
EN 1279-1, Glass in building — Insulating glass units — Part 1: Generalities, dimensional tolerances and
rules for the system description
ASTM C1036, Standard Specification for Flat Glass
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20492-1 and the following apply.
3.1
fog
visible deposits present after testing on the inside surface(s) of an insulating glass unit
3.2
sealed, insulating glass unit
pre-assembled unit, comprised of panes of glass that are sealed at the edges and separated by dehydrated
space(s), intended for vision areas of buildings
NOTE The unit is normally used for windows, window walls, picture windows, sliding doors, patio doors, or other
types of fenestration.
4 Requirements
4.1 Approach 1
No fog shall be visible after the test has ended in accordance with 5.1.4.
4.2 Approach 2
No permanent visual condensation shall be permitted in accordance with 5.2.4.
5 Test methods
5.1 Approach 1
5.1.1 Principle
Test specimens are placed in a chamber that is controlled at (50 ± 3) °C. A lamp is positioned in the bottom of
the chamber to supply heat and UV radiation. A chilled plate, controlled to a constant temperature of
(21 ± 2) °C, is positioned on the centre of each specimen. After 7 days of exposure, the test specimens are
examined at arm's length for fog.
5.1.2 Test specimens
Each test specimen shall measure (355 ± 6) mm by (505 ± 6) mm, and shall be composed of two or three
panes of clear, tinted or coated annealed, heat-strengthened, tempered or laminated glass.
The double-glazed test specimen shall be fabricated with at least one pane of clear, uncoated glass. The
triple-glazed test specimen shall be fabricated with at least one outer pane of clear, uncoated glass. The other
outer pane shall be fabricated with a glass that allows easy viewing of fog.
For double-glazed test specimens, the glass and airspace thicknesses shall be 4 mm glass with 12 mm
airspace or 5 mm glass with 6 mm airspace.
For triple-glazed test specimens, 4 mm glass with 6 mm airspaces shall be used.
Tolerance of glass thickness shall be in accordance with ASTM C1036.
Airspace tolerance(s) shall be ± 0,8 mm.
A minimum of two specimens of double-glazed or four specimens of triple-glazed test specimens shall be
submitted for testing.
NOTE 1 However, it is recommended to submit extra specimens in case of breakage.
Triple-glazed test specimens where the intermediate airspace divider is a plastic film shall be acceptable for
testing.
NOTE 2 The overall unit thickness of a test specimen has some limits. Testing laboratories are usually able to
accommodate 30 mm overall thickness. If testing thicker units, it is necessary to contact the testing laboratory prior to
manufacturing to ascertain their capabilities for testing thicker units.
Each specimen shall be permanently and legibly marked with the designation of the manufacturer, the date of
fabrication (month or quarter and year) and orientation intended in the field (for test specimens that have been
constructed with coated glass).
2 © ISO 2008 – All rights reserved
During all stages of exposure and storage, the test specimens shall be held in a vertical position with equal
support to all panes and no compression loading.
The selection of test specimens for testing shall be made at random, except when specimens have been
damaged in transit. Damaged test specimens shall not be tested.
Test specimens representing sealed, insulating glass units that are gas-filled shall be fabricated using the
same hole-sealing and gas-filling techniques as those used during manufacturing. For example, if a gas-filling
plug is used in manufacturing, then it should be used in the test specimens. It is not necessary that the
specimens be filled with gas provided that the gas is classified as inert.
Test specimens representing products that are normally filled with an inert gas in production may be submitted
air filled for this testing as long as they have been manufactured with the same techniques as used in
production.
Test specimens representing sealed, insulating glass units that include tubes intended to be left open shall be
fabricated with one tube. This tube shall be left open during testing. Test specimens representing sealed,
insulating glass units that include tubes intended to be closed off after shipping shall be fabricated with one
tube. The exterior end of this tube shall be closed prior to testing.
For test specimens representing sealed, insulating glass units that include internal components in the air
space, the grid formed by these components shall divide the test specimen into nine equal areas (3 × 3) (see
Figure 1).
Key
1 insulating glass spacer/edge seal
2 internal grids
Figure 1 — Test specimen with internal grids
The test specimens should be sealed a minimum of 4 weeks from the date of manufacture to allow for
stabilization before testing.
Before testing, the glass surfaces shall be checked to ensure that they are clean.
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