ISO 19916-3:2021
(Main)Glass in building — Vacuum insulating glass — Part 3: Test methods for evaluation of performance under temperature differences
Glass in building — Vacuum insulating glass — Part 3: Test methods for evaluation of performance under temperature differences
This document specifies test methods for evaluation of performance of vacuum insulating glass samples with rigid edge seal when subjected to temperature differences between the glass sheets. This document is not applicable to vacuum insulating glass samples with flexible edge seal.
Verre dans la construction — Vitrage isolant à lame de vide — Partie 3: Méthodes d’essai pour l’évaluation des performances en cas de différences de température
Le présent document spécifie des méthodes d’essai pour évaluer les performances d’échantillons de vitrage isolant à lame de vide présentant un joint de scellement rigide lorsque la température fluctue entre les feuilles de verre. Le présent document ne s’applique pas aux échantillons de vitrage isolant à lame de vide présentant un joint de scellement souple.
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INTERNATIONAL ISO
STANDARD 19916-3
First edition
2021-10
Glass in building — Vacuum insulating
glass —
Part 3:
Test methods for evaluation of
performance under temperature
differences
Verre dans la construction — Vitrage isolant à lame de vide —
Partie 3: Méthodes d’essai pour l’évaluation des performances en cas
de différences de température
Reference number
ISO 19916-3:2021(E)
© ISO 2021
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ISO 19916-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
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ISO 19916-3:2021(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test method . 2
4.1 Principle . 2
4.2 Test specimens. 2
4.2.1 Number of specimens . . 2
4.2.2 Size of specimens . 2
4.2.3 Design of specimens . 2
4.3 Apparatus . 2
4.4 Procedures . 4
4.4.1 General . 4
4.4.2 Measurement of U-value . 5
4.4.3 Setting of thermocouples . 5
4.4.4 Installation of specimens . 6
4.4.5 Temperature profile . 7
4.4.6 Determination of heat transfer coefficient . 8
4.4.7 Requirements . 8
5 Test report . 9
Annex A (informative) Guideline for the test apparatus .10
Annex B (informative) Stress induced in the glass sheets of vacuum insulating glass under
temperature differences .12
Bibliography .24
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ISO 19916-3:2021(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 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 160, Glass in building, Subcommittee SC 1,
Product considerations.
A list of all parts in the ISO 19916 series can be found on the ISO website.
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.
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INTERNATIONAL STANDARD ISO 19916-3:2021(E)
Glass in building — Vacuum insulating glass —
Part 3:
Test methods for evaluation of performance under
temperature differences
1 Scope
This document specifies test methods for evaluation of performance of vacuum insulating glass samples
with rigid edge seal when subjected to temperature differences between the glass sheets.
This document is not applicable to vacuum insulating glass samples with flexible edge seal.
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 19916-1, Glass in building — Vacuum insulating glass — Part 1: Basic specification of products and
evaluation methods for thermal and sound insulating performance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19916-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
heat transfer control board
board placed in a test chamber for reducing air flow around the vacuum insulating glass specimen
3.2
rigid edge seal
edge seal that prevents lateral relative movement between the glass sheets at the edge of the sheets
where the seal is formed, made from a rigid material such as glass or metal
3.3
flexible edge seal
edge seal structure allowing lateral movement between the two glass sheets
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ISO 19916-3:2021(E)
4 Test method
4.1 Principle
The evaluation of performance of a vacuum insulating glass specimen when subjected to a temperature
difference shall be performed in the following way:
a) the test conditions should ensure that a well-defined and reproducible temperature is established
in all regions of specimen;
b) stresses in the vacuum insulating glass specimen induced by the testing procedure from sources
other than the temperature difference should be as small as possible.
In order to satisfy these criteria:
— the specimen should be surrounded on each side by air at well-defined temperatures, and
— the specimen shall be oriented vertically; this effectively eliminates stresses due to bending under
gravitational forces.
NOTE Heat transfer on the glass surfaces and the glass edge constraint can have a significant influence on
the stress induced in the glass sheets of vacuum insulating glass under temperature differences. A detailed study
of this is given in Annex B.
4.2 Test specimens
4.2.1 Number of specimens
Three vacuum insulating glass specimens shall be submitted for testing.
4.2.2 Size of specimens
Each test specimen shall measure no less than 300 mm in width and 300 mm in height and no more
than 850 mm in width and 850 mm in height. Size of specimens shall be determined so that distance
between edge of the test specimen and inside wall of chamber is no less than 100 mm.
4.2.3 Design of specimens
In the following, a product range shall consist of specimens having the same edge seal structure and
material.
The specimen design with the lowest U-value in the product range shall be selected for the test. If there
are multiple designs with different thickness, one design shall be selected with the following process.
The specimen design with the minimum total nominal thickness in the product range shall be selected
for the test. If the selected design has different nominal thicknesses for the two glass sheets, the thicker
glass sheet shall face the hot side of the apparatus. If there is more than one specimen design of glass
thickness in the product range with the minimum total nominal thickness, the specimen to be tested
shall be the one for which the nominal thicknesses of the glass sheets differ the least.
EXAMPLE 1 For a product range with thickness in mm of 3 + 3, 3 + 5 and 5 + 5, only 3 + 3 is tested.
EXAMPLE 2 For a product range with thickness in mm of 3 + 5 and 5 + 5, only 3 + 5 is tested. The glass sheet
with 5 mm thickness faces to the hot side of the apparatus.
EXAMPLE 3 For a product range with thickness in mm of 3 + 5, 4 + 4 and 5 + 5, only 4 + 4 is tested.
4.3 Apparatus
The usual laboratory apparatus and, in particular, the following.
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ISO 19916-3:2021(E)
4.3.1 Temperature chamber, in which air temperature in a room can be controlled [see Figure 1, a)]
or in which air temperature in two rooms divided by the specimen and the frame can be controlled [see
Figure 1, b)].
4.3.2 Frame for specimen installation, consisting of frame and insulating board [see Figure 1, c)].
4.3.3 Heat transfer control board, consisting of flat metal plate.
4.3.4 Thermocouples.
4.3.5 Data recorder.
4.3.6 Adhesive tape.
a) Temperature chamber having one room
b) Temperature chamber having two rooms
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ISO 19916-3:2021(E)
c) Frame for specimen installation
Key
1 vacuum insulating glass specimen
2 frame for specimen installation
3 temperature controllable room
4 frame
5 insulating board
a
Air circulation.
Figure 1 — Examples of apparatus
4.4 Procedures
4.4.1 General
The U-value and the thermal resistance of each vacuum insulating glass specimen shall be determined
with the method described in 4.4.2.
The specimen shall be prepared for the test by attaching thermocouples for temperature measurements
to the surface, as shown in 4.4.3. The temperatures as measured by these thermocouples shall be
continually recorded in a data recorder during the test.
The specimen shall be installed in the test apparatus as shown in 4.4.4. A heat transfer control board
can be inserted between the circulating air and the surface of the specimen.
NOTE Annex A shows guidelines of the apparatus setup.
The test condition of the temperature difference to be applied to the specimen is described in 4.4.5.
The heat transfer coefficients on glass surfaces at the hot and cold sides shall be calculated from
measured temperatures using the method described in 4.4.6.
If one or both of the calculated heat transfer coefficients is outside of the acceptable range defined in
4.4.7.1, the heat transfer control board and/or the cooling/heating system control shall be adjusted to
correct the heat transfer coefficient(s) before continuing the test.
Failure criteria with the test shall be evaluated using measured temperatures as in 4.4.7.2.
The test procedure is shown in Figure 2.
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ISO 19916-3:2021(E)
Figure 2 — Flow of test procedure
4.4.2 Measurement of U-value
Before the specimen is installed in the apparatus, the U-value and the thermal resistance of each
specimen shall be determined with the method defined in Annex A of ISO 19916-1:2018.
4.4.3 Setting of thermocouples
Thermocouples of which accuracy is guaranteed shall be placed to measure temperature at the
following points. The thermocouples shall be applied on the glass and the heat transfer control board
surface in such a way that the thermocouples do not change the temperature at the measuring point.
— Hot and cold side glass surface close to the centre of the specimen.
— Air temperature of hot and cold side at the point facing the centre of the specimen and at 100 mm to
200 mm from the glass surface. When the heat transfer control board is used, thermocouple shall be
placed on the board at the point facing the centre of the specimen.
The diameter of thermocouple wire should be no more than 0,25 mm. The thermocouples should
thermally contact the glass and the board surface for no less than 20 mm in length, using thin adhesive
plastic tape having emissivity close to that of the surface. Metallic tape should not be used. The tip
of the thermocouple on the glass should be positioned at the mid-point between two pillars and the
contacting thermocouple wires should be located along a line mid-way between two adjacent rows of
pillars. An example is shown in Figure 3.
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ISO 19916-3:2021(E)
Key
1 pillar
2 tip of thermocouple
3 plastic adhesive tape
4 thermocouple wire
5 no less than 20 mm
Figure 3 — Example for setting a thermocouple on a glass surface
4.4.4 Installation of specimens
Place a specimen vertically at the opening of the test apparatus, taking care that significant stress is not
induced in the specimen by the method of fastening. In particular, all four edges shall be free to bend
during the test.
EXAMPLE The specimen is placed on two setting blocks at the bottom corners and fixed at four corners. The
setting blocks and fixing materials contact the specimen for a distance of no more than 30 mm from the corner of
the specimen. A diagram of the fixing structure is shown in Figure 4.
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ISO 19916-3:2021(E)
Key
1 vacuum insulating glass specimen
2 frame of the apparatus
3 setting block
4 fixing material
5 maximum 30 mm
Figure 4 — Example for fixing structure of the specimen
The gap between the specimen edge and the frame is sealed with a soft material, such as adhesive tape,
in order to stop air flow through the gap.
NOTE The edge constraints affect stress in the specimen. This document specifies the test method with no
edge constraint condition in order that test results obtained in different laboratories are comparable.
4.4.5 Temperature profile
Air temperature at both sides of the specimen shall be controlled at constant temperature. Temperature
difference of the hot side and cold side glass surfaces Δ T shall be at no less than the value calculated
VIG
with Formula (1), which is derived from condition of circumstance that air-to-air temperature difference
2 2
is 40 °C and heat transfer coefficients are 8 W/(m ·K) and 23 W/(m ·K) on both side of surfaces.
2 2
NOTE 8 W/(m ·K) and 23 W/(m ·K) are the respective values of the reference internal and external heat
transfer coefficients in ISO 10292.
ΔTR ≥×40 /(0,)168 + R (1)
VIG
where
ΔT
is the temperature difference of the hot side and cold side of the glass surfaces, in °C;
VIG
2
R
is the thermal resistance of the specimen, in m ·K/W.
The temperature difference of the hot side and cold side glass surfaces Δ T shall be controlled
VIG
within ±5 % range around average value during the steady-state temperature condition for at least 1 h.
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ISO 19916-3:2021(E)
4.4.6 Determination of heat transfer coefficient
The heat transfer coefficient at the centre of the specimen on the hot and cold sides shall be calculated
with Formulae (2) and (3):
hT=()ΔΔ//TR (2)
hot 21
hT= ΔΔ//TR (3)
()
cold 23
where
h
is the heat transfer coefficient on the hot surface of the specimen, in W/(m2·K);
hot
h
is the heat transfer coefficient on the cold surface of the specimen, in W/(m2·K);
cold
ΔT
is the average value, under steady-state temperature condition, of the temperature difference
1
between hot side air and hot side glass surface in °C, or the average value of temperature
difference between the board and the hot side glass surface in °C when the heat transfer
control board is used on the hot side;
ΔT
is the average value, under steady-state temperature condition, of the temperature difference
2
between hot side glass surface and cold side glass surface, in °C;
ΔT
is the average value, under steady-state temperature condition, of the temperature difference
3
between cold side air and cold side glass surface in °C, or the average value of temperature
difference between the board and the cold side glass surface in °C when the heat transfer
control board is used on the cold side.
2
NOTE The heat flow through the specimen Q, in W/m , can be calculated as shown below:
Q = ΔTh//()1 (4)
1 hot
Q =Δ TR/ (5)
2
Q = ΔTh//()1 (6)
3 cold
Formulae (2) and (3) can be derived from Formulae (4), (5) and (6).
4.4.7 Requirements
4.4.7.1 Heat transfer coefficient
The calculated heat transfer coefficient on the hot surface of the specimen h and heat transfer
hot
2 2
coefficient on the cold surface of the specimen h shall be 8,0 W/(m ·K) ± 2,0 W/(m ·K).
cold
2
NOTE The value 8,0 W/(m ·K) is selected as a free convection condition as used in Formula (13) of
2
ISO 10292:1994. The range ± 2,0 W/(m ·K) is to account for variations in the measurement.
4.4.7.2 Proportional change in the temperature difference
The proportional change in the temperature difference at the hot and cold sides of the specimen from
the beginning to the end of the steady-state temperature condition ΔT , in %, shall be calculated using
c
Formula (7).
ΔΔTT =× 100 − ΔΔTT/ (7)
ce bb
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ISO 19916-3:2021(E)
where
ΔT is the temperature difference between the hot and cold sides of the glass surface at the begin-
b
ning of the steady-state temperature condition at the test, in °C;
ΔT
is the temperature difference between the hot and cold sides of the glass surface at the end of
e
the steady-state temperature condition at the test, in °C.
If the calculated value of ΔT during the test of one or more of the test specimens exceeds 10 %, the
c
relevant set of specimens shall fail the test. Breakage due to laboratory handling is not considered as
test failure. Specimens broken due to laboratory handling shall be replaced and the measurement shall
be repeated.
NOTE The most likely failure mode under this test is mechanical failure leading to loss of vacuum. This is
detectable as a significant decrease in the temperature difference across the test specimen.
5 Test report
The test report shall contain the following items:
a) the international Standard used (including year of publication);
b) identification of the specimens:
— specimen description (e.g. manufacturer’s name, product name or other reference),
— length (mm),
— width (mm), and
— nominal thickness (mm);
c) description of the test apparatus, including:
— manufacturer’s name and model, if using a commercially-available apparatus,
— inside dimensions of the chamber, i.e. height, width and depth (mm), and
— dimensions and material of the heat transfer control board located inside the chamber, if used
(mm);
d) measurement and calculation results of
2 2
— the U-value [W/(m ·K)] and thermal resistance [m ·K /W] of each specimen,
— the average, the minimum and the maximum temperature difference (°C) between the hot side
and the cold side glass surfaces during the steady-state part of the test,
2
— the calculated heat transfer coefficient [W/(m ·K)] on the hot side glass surface h and the
hot
cold side of the glass surface h , and
cold
— the calculated proportional change of the temperature difference of the hot and the cold side of
each specimen at the beginning and the end of the steady-state temperature condition ΔT (%);
c
e) the evaluation result: pass or fail of the tests;
f) any deviations from this document which may have affected the result;
g) the date of the test.
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ISO 19916-3:2021(E)
Annex A
(informative)
Guideline for the test apparatus
A.1 General
This annex provides guidelines to make the test conditions suitable for the requirements in this
document.
Circulating air within the chamber can lead to a large heat transfer coefficient at the surface of the
specimen. This heat transfer coefficient can be controlled by inserting a heat transfer control board
between the circulating air and the specimen so that air does not directly flow against the vacuum
insulating glass specimen.
A.2 Guidelines
A.2.1 Option 1
The heat transfer control board allows a small amount of forced convection at the surface of the
specimen.
The dimensions of the heat transfer control board depend on the nature of the forced convection within
the chamber. For example, in case that circulating air flows from top to bottom, the board should be
sealed against the inside surfaces of the apparatus at the top and bottom so that the air does not flow
easily into the space between the board and the specimen. There should be gaps between the board and
the chamber on both sides.
A possible dimension would be a heat transfer control board having 15 mm to 50 mm gap between
the chamber wall and around 100 mm distant from the vacuum insulating glass specimen surface. An
example of the apparatus is shown in Figure A.1.
The board should be painted black on the surface facing to the specimen so that radiative heat transfer
is enhanced.
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ISO 19916-3:2021(E)
Key
1 vacuum insulating glass specimen
2 heat transfer control board
3 cooling or heating chamber
4 air circulation
Figure A.1 — Example of option 1
A.2.2 Option 2
For an apparatus in which there is negligible forced air flow at the surface of the specimen and sufficient
natural convective heat transfer is established at this surface, the heat transfer board is not necessary.
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ISO 19916-3:2021(E)
Annex B
(informative)
Stress induced in the glass sheets of vacuum insulating glass under
temperature differences
B.1 General
A temperature difference across a vacuum insulating glass specimen causes the hot glass sheet to
expand relative to the cold sheet. The rigid edge seal prevents relative movement of the sheets at
the edges. This produces mechanical stresses in the sheets and causes the structure to bend. These
stresses can be analysed using analytic and finite element modelling methods. This Annex presents
results of the nature and magnitude of the stresses obtained with both these modelling approaches and
discusses the different physical mechanisms that affect them. The results of the modelling approaches
were validated through systematic measurements performed on VIG units exposed to a well-defined
thermal load.
B.2 Modelling conditions
The temperature difference across a vacuum insulating glass is established in the modelling
configurations by locating the specimen between a hot environment at temperature T and a cold
H
environment at temperature T . The heat transfer coefficients between the hot and cold environments
C
and the corresponding glass surfaces are h and h respectively. Heat transfer between the hot and
1 2
cold environments beyond the vacuum insulating glass is prevented by a surrounding thermally
insulating baffle.
The configuration used to apply the thermal difference across a VIG unit should establish a stress
distribution over the glass panes that is close to that which would be observed in a typical window
installation. Primarily, this means that the heat transfer processes at the glass, on the hot and cold
sides, should at least be a combination of heat flow due to natural convection and radiation. There is
sometimes an extra convective component in practical installations due to forced air flow (wind) on
the cold side. However, in the practical test specified in this document, it is convenient to use equal heat
2
transfer coefficients on both glass sheets, to within an acceptable limit (that is, 8,0 ± 2,0 W/(m ·K)).
This reduces the complexity in the setup and reduces possible inconsistent outcomes between tests. As
discussed in the following sections, choice of the heat transfer coefficients can, by a significant margin,
affect stress levels. Nevertheless, the variations in stress (including the origin of the stress components)
are well understood and can be well predicted through analytical solutions.
Figure B.1 is a schematic diagram of a vacuum insulating glass specimen defining symbols for the
parameters used in this Annex.
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ISO 19916-3:2021(E)
Key
t glass thickness (mm)
L specimen size (mm)
w width of edge seal (mm)
1 vacuum layer
2 glass sheets
3 edge seal
Figure B.1 — Schematic diagram of a vacuum insulating glass specimen
As is conventional, the surfaces of the glass sheets are denoted Surface 1 to 4 from the cold side to the
hot side. Compressive stress is written as negative and tensile stress as positive.
The numerical results of modelling presented in this Annex are for an unconstrained vacuum insulating
glass specimen having properties given in Table B.1, under the thermal conditions given in Table B.2.
NOTE In both Tables B.1 and B.2, parameters that are denoted * are varied in some of the data presented
below.
Table B.1 — Details of specimen modelled
Glass thickness t (mm) 3*
Specimen size L × L (mm × mm) 350 × ^m350*
Width of edge seal w (mm) 4
Thickness of edge seal (mm) 0,2
Pillar separation (mm) 40
Pillar diameter (mm) 0,5
Corrected emissivity of low E coating 0,03
2
Glass-to-glass specimen conductance h [W/(m ·K)] 0,46
v
−6
Coefficient of thermal e
...
NORME ISO
INTERNATIONALE 19916-3
Première édition
2021-10
Verre dans la construction — Vitrage
isolant à lame de vide —
Partie 3:
Méthodes d’essai pour l’évaluation des
performances en cas de différences de
température
Glass in building — Vacuum insulating glass —
Part 3: Test methods for evaluation of performance under
temperature differences
Numéro de référence
ISO 19916-3:2021(F)
© ISO 2021
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ISO 19916-3:2021(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2021
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
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Web: www.iso.org
Publié en Suisse
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ISO 19916-3:2021(F)
Sommaire Page
Avant-propos .iv
1 Domaine d’application . 1
2 Références normatives .1
3 Termes et définitions . 1
4 Méthode d’essai . 2
4.1 Principe . 2
4.2 Éprouvettes . 2
4.2.1 Nombre d’éprouvettes . 2
4.2.2 Taille des éprouvettes . 2
4.2.3 Modèle des éprouvettes . 2
4.3 Appareillage . 3
4.4 Modes opératoires . 4
4.4.1 Généralités . 4
4.4.2 Mesure du coefficient de transmission thermique U . 5
4.4.3 Installation des thermocouples . 5
4.4.4 Installation des éprouvettes . 6
4.4.5 Profil de températures . 7
4.4.6 Détermination du coefficient de transfert thermique . 8
4.4.7 Exigences . 8
5 Rapport d’essai . 9
Annexe A (informative) Ligne directrice relative à l’appareillage d’essai .11
Annexe B (informative) Tension induite dans les feuilles de verre isolant à lame de vide en
cas de différences de température .13
Bibliographie .25
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ISO 19916-3:2021(F)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d’approbation requis pour les différents types de documents ISO. Le présent document
a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2
(voir www.iso.org/directives).
L’attention est attirée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de
brevets reçues par l’ISO (voir www.iso.org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion
de l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir www.iso.org/avant-propos.
Le présent document a été élaboré par le comité technique ISO/TC 160, Verre dans la construction, sous-
comité SC 1, Produits.
Une liste de toutes les parties de la série ISO 19916 se trouve sur le site internet de l’ISO.
Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l’adresse www.iso.org/fr/members.html.
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NORME INTERNATIONALE ISO 19916-3:2021(F)
Verre dans la construction — Vitrage isolant à lame de
vide —
Partie 3:
Méthodes d’essai pour l’évaluation des performances en
cas de différences de température
1 Domaine d’application
Le présent document spécifie des méthodes d’essai pour évaluer les performances d’échantillons de
vitrage isolant à lame de vide présentant un joint de scellement rigide lorsque la température fluctue
entre les feuilles de verre.
Le présent document ne s’applique pas aux échantillons de vitrage isolant à lame de vide présentant un
joint de scellement souple.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s’applique (y compris les
éventuels amendements).
ISO 19916-1, Verre dans la construction — Vitrage isolant à lame de vide — Partie 1: Spécification de base
des produits et méthodes d'évaluation des performances d'isolation thermique et acoustique
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions de l’ISO 19916-1 ainsi que les suivants,
s’appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l'adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l'adresse https:// www .electropedia .org/
3.1
panneau de contrôle de transfert thermique
panneau placé dans la chambre d’essai pour réduire le flux d’air autour de l’éprouvette du vitrage
isolant à lame de vide
3.2
joint de scellement rigide
joint de scellement empêchant les mouvements latéraux relatifs entre les feuilles de verre, posé au bord
de ces dernières et fait d’un matériau rigide comme le verre, le métal, etc
3.3
joint de scellement souple
structure de joint de scellement permettant les mouvements latéraux entre deux feuilles de verre
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ISO 19916-3:2021(F)
4 Méthode d’essai
4.1 Principe
L’évaluation de la défaillance d’une éprouvette de vitrage isolant à lame de vide soumise à une différence
de température doit être effectuée de la manière suivante:
a) il convient que les conditions d’essai assurent une température bien définie et reproductible sur
l’intégralité de l’éprouvette;
b) il convient que les tensions exercées sur l’éprouvette de vitrage isolant à lame de vide induites par
le mode opératoire d’essai mais autres que celles induites par la différence de température soient
aussi minimes que possible.
Afin de satisfaire à ces critères:
— il convient que l’éprouvette soit entourée de chaque côté par de l’air à des températures bien définies,
et
— l’éprouvette doit être positionnée verticalement; cela permet en effet d’éliminer toute tension de
flexion du fait des forces gravitationnelles.
NOTE Le transfert thermique sur les surfaces de vitrage et la contrainte sur le bord du vitrage peuvent avoir
une influence considérable sur les tensions exercées sur les feuilles du vitrage isolant à lame de vide en cas de
différences de température. Une méthode détaillée est donnée dans l’Annexe B.
4.2 Éprouvettes
4.2.1 Nombre d’éprouvettes
Trois éprouvettes de vitrage isolant à lame de vide doivent être soumises à essai.
4.2.2 Taille des éprouvettes
Chaque éprouvette doit mesurer au minimum 300 mm de large et 300 mm de haut et au maximum
850 mm de large et 850 mm de haut. La taille des éprouvettes doit être déterminée de manière que la
distance entre le bord de l’éprouvette et la paroi intérieure de la chambre d’essai soit au moins égale à
100 mm.
4.2.3 Modèle des éprouvettes
Dans ce qui suit, une gamme de produits doit être composée d’éprouvettes présentant la même structure
et le même matériau de joint de scellement.
Le modèle d’éprouvette présentant le coefficient de transmission thermique U le plus faible dans la
gamme de produits doit être sélectionné pour l’essai. S’il existe plusieurs de ces modèles présentant
différentes épaisseurs, le modèle doit être sélectionné en fonction du processus suivant.
Le modèle d’éprouvette présentant l’épaisseur nominale totale la plus faible dans la gamme de produits
doit être sélectionné pour l’essai. Si le modèle sélectionné présente différentes épaisseurs nominales
pour ses deux feuilles de verre, la feuille de verre la plus épaisse doit faire face au côté chaud de
l’appareillage. S’il existe plusieurs modèles d’éprouvette pour l’épaisseur de vitrage dans la gamme de
produits et présentant l’épaisseur nominale totale la plus faible, l’éprouvette à soumettre à essai doit
être celle dont les épaisseurs nominales entre les feuilles de verre diffèrent le moins.
EXEMPLE 1 Pour une gamme de produits présentant des épaisseurs en mm de 3 + 3, 3 + 5 et 5 + 5, seul le
modèle offrant les dimensions 3 + 3 est soumis à essai.
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ISO 19916-3:2021(F)
EXEMPLE 2 Pour une gamme de produits présentant des épaisseurs en mm de 3 + 5 et 5 + 5, seul le modèle
offrant les dimensions de 3 + 5 est soumis à essai. La feuille de verre de 5 mm d’épaisseur fait face au côté chaud
de l’appareillage.
EXEMPLE 3 Pour une gamme de produits présentant des épaisseurs en mm de 3 + 5, 4 + 4 et 5 + 5, seul le
modèle offrant les dimensions de 4+4 est soumis à essai.
4.3 Appareillage
Appareillage de laboratoire habituel et, en particulier, ce qui suit.
4.3.1 Chambre à température, dans laquelle la température de l’air dans un espace peut être
contrôlée [voir Figure 1, a)] ou dans laquelle la température de l’air dans deux espaces séparés par
l’éprouvette et le châssis peut être contrôlée [voir Figure 1, b)].
4.3.2 Châssis pour installer l’éprouvette, composé d’un cadre et d’un panneau isolant [voir
Figure 1, c)].
4.3.3 Panneau de contrôle de transfert thermique, composé d’une plaque de métal plate.
4.3.4 Thermocouples.
4.3.5 Dispositif d’enregistrement des données.
4.3.6 Ruban adhésif.
a) Chambre à température disposant d’un espace
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ISO 19916-3:2021(F)
b) Chambre à température disposant de deux espaces
c) Châssis pour installer l’éprouvette
Légende
1 éprouvette de vitrage isolant à lame de vide
2 châssis pour installer l’éprouvette
3 chambre à température contrôlable
4 châssis
5 panneau isolant
a
Circulation de l’air.
Figure 1 — Exemple d’appareillage
4.4 Modes opératoires
4.4.1 Généralités
Le coefficient de transmission thermique U et la résistance thermique de chaque éprouvette de vitrage
isolant à lame de vide doivent être déterminés selon la méthode décrite en 4.4.2.
L’éprouvette doit être préparée pour l’essai en installant des thermocouples pour mesurer la
température de surface, comme indiqué en 4.4.3. Les températures mesurées par ces thermocouples
doivent être systématiquement consignées à l’aide d’un dispositif d’enregistrement des données
pendant l’essai.
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ISO 19916-3:2021(F)
L’éprouvette doit être installée sur l’appareillage d’essai comme indiqué en 4.4.4. Un panneau de contrôle
de transfert thermique peut être inséré entre l’air en circulation et la surface de l’éprouvette.
NOTE L’Annexe A fournit des lignes directrices pour la configuration de l’appareillage.
Les conditions d’essai relatives à la différence de température à appliquer à l’éprouvette sont décrites
en 4.4.5.
Les coefficients de transfert thermique sur les surfaces du vitrage du côté froid et du côté chaud doivent
être calculés à partir des températures mesurées à l’aide de la méthode décrite en 4.4.6.
Si l’un des coefficients de transfert thermique calculés, ou les deux, est en dehors de la plage acceptable
définie en 4.4.7.1, le panneau de contrôle de transfert thermique et/ou la commande du système de
refroidissement/chauffage doivent être paramétrés pour corriger le ou les coefficients de transfert
thermique avant de poursuivre l’essai.
Les critères d’échec de l’essai doivent être évalués à l’aide des températures mesurées comme indiqué
en 4.4.7.2.
Le mode opératoire d’essai est spécifié à la Figure 2.
Figure 2 — Organigramme du mode opératoire d’essai
4.4.2 Mesure du coefficient de transmission thermique U
Avant d’installer l’éprouvette dans l’appareillage, le coefficient de transmission thermique U et la
résistance thermique de chaque éprouvette doivent être déterminés selon la méthode décrite dans
l’Annexe A de l’ISO 19916-1:2018.
4.4.3 Installation des thermocouples
Des thermocouples dont la précision est garantie doivent être placés pour mesurer la température aux
points suivants. Les thermocouples doivent être appliqués sur la surface du vitrage et du panneau de
contrôle de transfert thermique de manière que les thermocouples ne modifient pas la température au
point de mesure.
— Surface du vitrage du côté chaud et du côté froid près du centre de l’éprouvette.
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ISO 19916-3:2021(F)
— Température de l’air du côté chaud et du côté froid au point faisant face au centre de l’éprouvette et à
100 mm à 200 mm de la surface du vitrage. Lorsque le panneau de contrôle de transfert thermique est
utilisé, le thermocouple doit être placé sur le panneau au point faisant face au centre de l’éprouvette.
Il convient que le diamètre du fil du thermocouple ne soit pas supérieur à 0,25 mm. Il convient que les
thermocouples soient thermiquement en contact avec le vitrage ainsi qu’avec la surface du panneau
sur au moins 20 mm de long, ceci grâce à un ruban adhésif plastique fin offrant une émissivité proche
de celle de la surface. Il convient que les rubans adhésifs métalliques ne soient pas utilisés. Il convient
que la pointe du thermocouple soit positionnée au point milieu entre deux entretoises et il convient que
les fils de contact du thermocouple soient situés le long d’une ligne à mi-chemin entre deux rangées
adjacentes d’entretoises. Un exemple est présenté à la Figure 3.
Légende
1 entretoise
2 pointe du thermocouple
3 ruban adhésif plastique
4 fil de thermocouple
5 20 mm au moins
Figure 3 — Exemple d’installation d’un thermocouple sur une surface du vitrage
4.4.4 Installation des éprouvettes
Placer une éprouvette à la verticale à l’entrée de l’appareillage d’essai en veillant à ce que l’éprouvette
ne subisse aucune tension significative à cause de la méthode de fixation. Les quatre bords doivent
notamment être libres de fléchir pendant l’essai.
EXEMPLE L’éprouvette est placée sur deux cales d’assise situées dans les coins en bas et est fixée en ses
quatre coins. Les cales d’assise et les matériaux de fixation sont en contact avec l’éprouvette sur une distance
de 30 mm maximum à partir de chaque coin de l’éprouvette. Un schéma de la structure de fixation est indiqué à
la Figure 4.
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ISO 19916-3:2021(F)
Légende
1 éprouvette de vitrage isolant à lame de vide
2 châssis de l’appareillage
3 cale d’assise
4 matériau de fixation
5 30 mm maximum
Figure 4 — Structure de fixation de l’éprouvette
L’écart entre le bord de l’éprouvette et le châssis est comblé avec un matériau souple, comme du ruban
adhésif, afin d’interrompre le flux d’air circulant dans cet écart.
NOTE Les contraintes sur les bords affectent la tension dans l’éprouvette. Le présent document spécifie la
méthode d’essai sans condition de contrainte sur les bords afin que les résultats d’essai obtenus dans différents
laboratoires soient comparables.
4.4.5 Profil de températures
La température de l’air des deux côtés de l’éprouvette doit être contrôlée à une température constante.
La différence de température des surfaces du vitrage du côté chaud et du côté froid Δ T ne doit pas
VIG
être inférieure à la valeur calculée à l’aide de la Formule (1), dérivée de la condition de circonstance
selon laquelle la différence de température air-air est de 40 °C et les coefficients de transfert thermique
2 2
sont de 8 W/(m ·K) et 23 W/(m ·K) sur les deux côtés des surfaces.
2 2
NOTE 8 W/(m ·K) et 23 W/(m ·K) correspondent aux valeurs respectives des coefficients de transfert
[1]
thermique interne et externe de référence dans l’ISO 10292 :
ΔTR ≥×40 /(0,)168 + R (1)
VIG
où
ΔT
est la différence de température des surfaces du vitrage du côté chaud et du côté froid [°C];
VIG
2
R
est la résistance thermique de l’éprouvette [m ·K/W].
La différence de température des surfaces du vitrage du côté chaud et du côté froid Δ T doit être
VIG
contrôlée dans une plage de ± 5 % par rapport à la valeur moyenne pendant la condition de température
en régime stationnaire durant au moins 1 heure.
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ISO 19916-3:2021(F)
4.4.6 Détermination du coefficient de transfert thermique
Le coefficient de transfert thermique au centre de l’éprouvette sur les côtés chaud et froid doit être
calculé grâce aux équations suivantes:
hT=()ΔΔ//TR (2)
chaud 21
hT= ΔΔ//TR (3)
()
froid 23
où
2
h est le coefficient de transfert thermique sur la surface chaude de l’éprouvette [W/(m ·K)];
chaud
2
h est le coefficient de transfert thermique sur la surface froide de l’éprouvette [W/(m ·K)];
froid
ΔT est la valeur moyenne, en condition de température en régime stationnaire, de la différence
1
de température entre l’air du côté chaud et la surface du vitrage du côté chaud. Si le panneau
de contrôle de transfert thermique est utilisé du côté chaud, valeur moyenne de la différence
de température entre le panneau et la surface du vitrage du côté chaud [°C];
ΔT est la valeur moyenne, en condition de température en régime stationnaire, de la différence
2
de température entre la surface du vitrage du côté chaud et la surface du vitrage du côté
froid [°C];
ΔT est la valeur moyenne, en condition de température en régime stationnaire, de la différence
3
de température entre la surface du vitrage du côté froid et l’air du côté froid. Si le panneau
de contrôle de transfert thermique est utilisé du côté froid, valeur moyenne de la différence
de température entre la surface du vitrage du côté froid et le panneau [°C].
2
NOTE Le flux thermique à travers l’éprouvette Q, en W/m peut être calculé comme démontré ci-dessous:
Q = ΔTh//1 (4)
()
1 chaud
Q =Δ TR/ (5)
2
Q = ΔTh//1 (6)
()
3 froid
Les Formules (2) et (3) peuvent être dérivées à partir des Formules (4), (5) et (6).
4.4.7 Exigences
4.4.7.1 Coefficient de transfert thermique
Le coefficient de transfert thermique calculé sur la surface chaude de l’éprouvette h et le coefficient
chaud
de transfert thermique calculé sur la surface froide de l’éprouvette h doivent être de 8,0 W/
froid
2 2
(m ·K) ± 2,0 W/(m ·K).
2
NOTE 8,0 W/(m ·K) est choisi en tant que condition de convection libre comme dans l’Équation (13) de
2
l’ISO 10292:1994 ± 2,0 W/(m ·K) sert à prendre en compte les variations de la mesure.
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ISO 19916-3:2021(F)
4.4.7.2 Changement proportionnel dans la différence de température
Le changement proportionnel dans la différence de température sur les côtés chaud et froid de
l’éprouvette du début à la fin de la condition de température en régime stationnaire ΔT , en % doit être
c
calculé à l’aide de la Formule (7):
ΔΔTT =× 100 − ΔΔTT/ (7)
ce bb
où
ΔT est la différence de température entre le côté chaud et le côté froid de la surface du vitrage au
b
début de la condition de température en régime stationnaire pendant l’essai [°C];
ΔT est la différence de température entre le côté chaud et le côté froid de la surface du vitrage à
e
la fin de la condition de température en régime stationnaire pendant l’essai [°C].
Si la valeur calculée de ΔT durant l’essai d’une ou de plusieurs des éprouvettes dépasse 10 %, l’ensemble
c
des éprouvettes concernées doit être déclaré comme non conforme à l’essai. Si une éprouvette est
endommagée pendant la manipulation en laboratoire, cela n’est pas considéré comme un échec de
l’essai. Les unités endommagées au cours de la manipulation en laboratoire doivent être remplacées et
les mesurages doivent être répétés.
NOTE Le mode d’échec le plus probable lors de cet essai consiste en un dysfonctionnement mécanique
entraînant la perte du vide. Une diminution significative de la différence de température dans toute l’unité d’essai
permet de détecter ce phénomène.
5 Rapport d’essai
Le rapport d’essai doit inclure les éléments suivants:
a) la norme internationale utilisée (comprenant l’année de publication):
b) l’identification des éprouvettes:
— la description des éprouvettes (par exemple, nom du fabricant, nom du produit ou autre référence,
etc.);
— la longueur (mm);
— la largeur (mm);
— l’épaisseur nominale (mm);
c) une description de l’appareillage d’essai utilisé, notamment:
— le nom du fabricant et le modèle, en cas d’utilisation d’un appareillage disponible dans le commerce;
— les dimensions internes de la chambre (à savoir la hauteur et la profondeur (mm));
— les dimensions et le matériau du panneau de contrôle de transfert thermique situé à l’intérieur de la
chambre, le cas échéant (mm);
d) les résultats des mesurages et des calculs:
2 2
— la valeur de transmission thermique U [W/(m ·K)] et la résistance thermique [m ·K /W] de chaque
éprouvette;
— la différence de température moyenne, minimale et maximale [°C] entre les surfaces du vitrage du
côté chaud et du côté froid pendant la partie en régime stationnaire de l’essai;
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ISO 19916-3:2021(F)
2
— le coefficient de transfert thermique calculé [W/(m ·K)] sur la surface du vitrage du côté chaud
h et sur la surface du vitrage du côté froid h ;
chaud froid
— le changement proportionnel calculé de la différence de température des côtés chaud et froid de
chaque éprouvette au début et à la fin de la condition de température en régime stationnaireΔT (%);
c
e) le résultat de l’évaluation: la conformité ou non-conformité aux essais;
f) tout écart par rapport au présent document susceptible d’avoir influé sur le résultat;
g) la date de l’essai.
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ISO 19916-3:2021(F)
Annexe A
(informative)
Ligne directrice relative à l’appareillage d’essai
A.1 Généralités
La présente annexe spécifie les lignes directrices pour rendre les conditions d’essai conformes aux
exigences du présent document.
L’air circulant dans la chambre peut générer un coefficient de transfert thermique important à la
surface de l’éprouvette. Ce coefficient de transfert thermique peut être contrôlé en insérant un panneau
de contrôle de transfert thermique entre l’air en circulation et l’éprouvette de façon que l’air ne circule
pas directement contre l’éprouvette de vitrage isolant à lame de vide.
A.2 Lignes directrices
A.2.1 Option 1
Le panneau de contrôle de transfert thermique permet une convection forcée limitée à la surface de
l’éprouvette.
Les dimensions du panneau de contrôle de transfert thermique dépendent de la nature de la convection
forcée à l’intérieur de la chambre. Par exemple, si l’air circule de haut en bas, il convient que le panneau
soit scellé hermétiquement contre les surfaces internes de l’appareillage en haut et en bas afin que l’air
ne circule pas facilement dans l’espace situé entre le panneau et l’éprouvette. Il convient que des écarts
soient créés entre le panneau et la chambre des deux côtés.
Il est possible pour un panneau de contrôle de transfert thermique de marquer un écart de 15 ~ 50 mm
avec la paroi de la chambre et d’être séparé d’environ 100 mm de la surface de l’éprouvette de vitrage
isolant à lame de vide. La Figure A.1 montre un exemple d’appareillage.
Il convient que la surface du panneau faisant face à l’éprouvette soit peinte en noir de façon à ce que le
transfert thermique radiatif soit optimisé.
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ISO 19916-3:2021(F)
Légende
1 éprouvette de vitrage isolant à lame de vide
2 panneau de contrôle de transfert thermique
3 chambre de refroidissement ou de chauffage
4 circulation de l’air
Figure A.1 — Exemple pour l’option 1
A.2.2 Option 2
Pour un appareillage dans lequel un flux d’air forcé négligeable circule à la surface de l’éprouvette et un
transfert thermique convectif naturel est établi à sa surface, le panneau de transfert thermique n’est
pas nécessaire.
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ISO 19916-3:2021(F)
Annexe B
(informative)
Tension induite dans les feuilles de verre isolant à lame de vide en
cas d
...
INTERNATIONAL ISO
STANDARD 19916-3
First edition
Glass in building — Vacuum insulating
glass —
Part 3:
Test methods for evaluation of
performance under temperature
differences
Verre dans la construction — Vitrage isolant à lame de vide —
Partie 3: Méthodes d’essai pour l’évaluation des performances en cas
de différences de température
PROOF/ÉPREUVE
Reference number
ISO 19916-3:2021(E)
©
ISO 2021
---------------------- Page: 1 ----------------------
ISO 19916-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 19916-3:2021(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test method . 2
4.1 Principle . 2
4.2 Test specimens . 2
4.2.1 Number of specimens . 2
4.2.2 Size of specimens. 2
4.2.3 Design of specimens . 2
4.3 Apparatus . 2
4.4 Procedures . 4
4.4.1 General. 4
4.4.2 Measurement of U-value . 5
4.4.3 Setting of thermocouples . 5
4.4.4 Installation of specimens . 6
4.4.5 Temperature profile . 7
4.4.6 Determination of heat transfer coefficient . 8
4.4.7 Requirements . 8
5 Test report . 9
Annex A (informative) Guideline for the test apparatus .11
Annex B (informative) Stress induced in the glass sheets of vacuum insulating glass under
temperature differences .13
Bibliography .25
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ISO 19916-3:2021(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 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 160, Glass in building, Subcommittee,
SC 1, Product considerations.
A list of all parts in the ISO 19916 series can be found on the ISO website.
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.
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INTERNATIONAL STANDARD ISO 19916-3:2021(E)
Glass in building — Vacuum insulating glass —
Part 3:
Test methods for evaluation of performance under
temperature differences
1 Scope
This document specifies test methods for evaluation of performance of vacuum insulating glass samples
with rigid edge seal when subjected to temperature differences between the glass sheets.
This document is not applicable to vacuum insulating glass samples with flexible edge seal.
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 19916-1, Glass in building — Vacuum insulating glass — Part 1: Basic specification of products and
evaluation methods for thermal and sound insulating performance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19916-1 and the following
apply.
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 https:// www .electropedia .org/
3.1
heat transfer control board
board placed in a test chamber for reducing air flow around the vacuum insulating glass specimen
3.2
rigid edge seal
edge seal that prevents lateral relative movement between the glass sheets at the edge of the sheets
where the seal is formed, made from a rigid material such as glass or metal
3.3
flexible edge seal
edge seal structure allowing lateral movement between the two glass sheets
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ISO 19916-3:2021(E)
4 Test method
4.1 Principle
The evaluation of performance of a vacuum insulating glass specimen when subjected to a temperature
difference shall be performed in the following way:
a) the test conditions should ensure that a well-defined and reproducible temperature is established
in all regions of specimen;
b) stresses in the vacuum insulating glass specimen induced by the testing procedure from sources
other than the temperature difference should be as small as possible.
In order to satisfy these criteria:
— the specimen should be surrounded on each side by air at well-defined temperatures, and
— the specimen shall be oriented vertically; this effectively eliminates stresses due to bending under
gravitational forces.
NOTE Heat transfer on the glass surfaces and the glass edge constraint can have a significant influence on
the stress induced in the glass sheets of vacuum insulating glass under temperature differences. A detailed study
of this is given in Annex B.
4.2 Test specimens
4.2.1 Number of specimens
Three vacuum insulating glass specimens shall be submitted for testing.
4.2.2 Size of specimens
Each test specimen shall measure no less than 300 mm in width and 300 mm in height and no more
than 850 mm in width and 850 mm in height. Size of specimens shall be determined so that distance
between edge of the test specimen and inside wall of chamber is no less than 100 mm.
4.2.3 Design of specimens
In the following, a product range shall consist of specimens having the same edge seal structure and
material.
The specimen design with the lowest U-value in the product range shall be selected for the test. If there
are multiple designs with different thickness, one design shall be selected with the following process.
The specimen design with the minimum total nominal thickness in the product range shall be selected
for the test. If the selected design has different nominal thicknesses for the two glass sheets, the thicker
glass sheet shall face the hot side of the apparatus. If there is more than one specimen design of glass
thickness in the product range with the minimum total nominal thickness, the specimen to be tested
shall be the one for which the nominal thicknesses of the glass sheets differ the least.
EXAMPLE 1 For a product range with thickness in mm of 3 + 3, 3 + 5 and 5 + 5, only 3 + 3 is tested.
EXAMPLE 2 For a product range with thickness in mm of 3 + 5 and 5 + 5, only 3 + 5 is tested. The glass sheet
with 5 mm thickness faces to the hot side of the apparatus.
EXAMPLE 3 For a product range with thickness in mm of 3 + 5, 4 + 4 and 5 + 5, only 4 + 4 is tested.
4.3 Apparatus
The usual laboratory apparatus and, in particular, the following.
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ISO 19916-3:2021(E)
4.3.1 Temperature chamber, in which air temperature in a room can be controlled [see Figure 1, a)]
or in which air temperature in two rooms divided by the specimen and the frame can be controlled [see
Figure 1, b)].
4.3.2 Frame for specimen installation, consisting of frame and insulating board [see Figure 1, c)].
4.3.3 Heat transfer control board, consisting of flat metal plate.
4.3.4 Thermocouples.
4.3.5 Data recorder.
4.3.6 Adhesive tape.
a) Temperature chamber having one room
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ISO 19916-3:2021(E)
b) Temperature chamber having two rooms
c) Frame for specimen installation
Key
1 vacuum insulating glass specimen
2 frame for specimen installation
3 temperature controllable room
4 frame
5 insulating board
a
Air circulation.
Figure 1 — Examples of apparatus
4.4 Procedures
4.4.1 General
The U-value and the thermal resistance of each vacuum insulating glass specimen shall be determined
with the method described in 4.4.2.
The specimen shall be prepared for the test by attaching thermocouples for temperature measurements
to the surface, as shown in 4.4.3. The temperatures as measured by these thermocouples shall be
continually recorded in a data recorder during the test.
The specimen shall be installed in the test apparatus as shown in 4.4.4. A heat transfer control board
can be inserted between the circulating air and the surface of the specimen.
NOTE Annex A shows guidelines of the apparatus setup.
The test condition of the temperature difference to be applied to the specimen is described in 4.4.5.
The heat transfer coefficients on glass surfaces at the hot and cold sides shall be calculated from
measured temperatures using the method described in 4.4.6.
If one or both of the calculated heat transfer coefficients is outside of the acceptable range defined in
4.4.7.1, the heat transfer control board and/or the cooling/heating system control shall be adjusted to
correct the heat transfer coefficient(s) before continuing the test.
Failure criteria with the test shall be evaluated using measured temperatures as in 4.4.7.2.
The test procedure is shown in Figure 2.
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ISO 19916-3:2021(E)
Figure 2 — Flow of test procedure
4.4.2 Measurement of U-value
Before the specimen is installed in the apparatus, the U-value and the thermal resistance of each
specimen shall be determined with the method defined in Annex A of ISO 19916-1:2018.
4.4.3 Setting of thermocouples
Thermocouples of which accuracy is guaranteed shall be placed to measure temperature at the
following points. The thermocouples shall be applied on the glass and the heat transfer control board
surface in such a way that the thermocouples do not change the temperature at the measuring point.
— Hot and cold side glass surface close to the centre of the specimen.
— Air temperature of hot and cold side at the point facing the centre of the specimen and at 100 mm to
200 mm from the glass surface. When the heat transfer control board is used, thermocouple shall be
placed on the board at the point facing the centre of the specimen.
The diameter of thermocouple wire should be no more than 0,25 mm. The thermocouples should
thermally contact the glass and the board surface for no less than 20 mm in length, using thin adhesive
plastic tape having emissivity close to that of the surface. Metallic tape should not be used. The tip
of the thermocouple on the glass should be positioned at the mid-point between two pillars and the
contacting thermocouple wires should be located along a line mid-way between two adjacent rows of
pillars. An example is shown in Figure 3.
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ISO 19916-3:2021(E)
Key
1 pillar
2 tip of thermocouple
3 plastic adhesive tape
4 thermocouple wire
5 no less than 20 mm
Figure 3 — Example for setting a thermocouple on a glass surface
4.4.4 Installation of specimens
Place a specimen vertically at the opening of the test apparatus, taking care that significant stress is not
induced in the specimen by the method of fastening. In particular, all four edges shall be free to bend
during the test.
EXAMPLE The specimen is placed on two setting blocks at the bottom corners and fixed at four corners. The
setting blocks and fixing materials contact the specimen for a distance of no more than 30 mm from the corner of
the specimen. A diagram of the fixing structure is shown in Figure 4.
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ISO 19916-3:2021(E)
Key
1 vacuum insulating glass specimen
2 frame of the apparatus
3 setting block
4 fixing material
5 maximum 30 mm
Figure 4 — Example for fixing structure of the specimen
The gap between the specimen edge and the frame is sealed with a soft material, such as adhesive tape,
in order to stop air flow through the gap.
NOTE The edge constraints affect stress in the specimen. This document specifies the test method with no
edge constraint condition in order that test results obtained in different laboratories are comparable.
4.4.5 Temperature profile
Air temperature at both sides of the specimen shall be controlled at constant temperature. Temperature
difference of the hot side and cold side glass surfaces Δ T shall be at no less than the value calculated
VIG
with Formula (1), which is derived from condition of circumstance that air-to-air temperature difference
2 2
is 40 °C and heat transfer coefficients are 8 W/(m ·K) and 23 W/(m ·K) on both side of surfaces.
2 2
NOTE 8 W/(m ·K) and 23 W/(m ·K) are the respective values of the reference internal and external heat
transfer coefficients in ISO 10292.
ΔTR ≥×40 /(0,)168 + R (1)
VIG
where
ΔT
is the temperature difference of the hot side and cold side of the glass surfaces, in °C;
VIG
2
R
is the thermal resistance of the specimen, in m ·K/W.
The temperature difference of the hot side and cold side glass surfaces Δ T shall be controlled
VIG
within ±5 % range around average value during the steady-state temperature condition for at least 1 h.
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ISO 19916-3:2021(E)
4.4.6 Determination of heat transfer coefficient
The heat transfer coefficient at the centre of the specimen on the hot and cold sides shall be calculated
with Formulae (2) and (3):
hT=()ΔΔ//TR (2)
hot 21
hT= ΔΔ//TR (3)
()
cold 23
where
h
is the heat transfer coefficient on the hot surface of the specimen, in W/(m2·K);
hot
h
is the heat transfer coefficient on the cold surface of the specimen, in W/(m2·K);
cold
ΔT
is the average value, under steady-state temperature condition, of the temperature difference
1
between hot side air and hot side glass surface in °C, or the average value of temperature
difference between the board and the hot side glass surface in °C when the heat transfer
control board is used on the hot side;
ΔT
is the average value, under steady-state temperature condition, of the temperature difference
2
between hot side glass surface and cold side glass surface, in °C;
ΔT
is the average value, under steady-state temperature condition, of the temperature difference
3
between cold side air and cold side glass surface in °C, or the average value of temperature
difference between the board and the cold side glass surface in °C when the heat transfer
control board is used on the cold side.
2
NOTE The heat flow through the specimen Q, in W/m , can be calculated as shown below:
Q = ΔTh//()1 (4)
1 hot
Q =Δ TR/ (5)
2
Q = ΔTh//()1 (6)
3 cold
Formulae (2) and (3) can be derived from Formulae (4), (5) and (6).
4.4.7 Requirements
4.4.7.1 Heat transfer coefficient
The calculated heat transfer coefficient on the hot surface of the specimen h and heat transfer
hot
2 2
coefficient on the cold surface of the specimen h shall be 8,0 W/(m ·K) ± 2,0 W/(m ·K).
cold
2
NOTE The value 8,0 W/(m ·K) is selected as a free convection condition as used in Formula (13) of
2
ISO 10292:1994. The range ± 2,0 W/(m ·K) is to account for variations in the measurement.
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ISO 19916-3:2021(E)
4.4.7.2 Proportional change in the temperature difference
The proportional change in the temperature difference at the hot and cold sides of the specimen from
the beginning to the end of the steady-state temperature condition ΔT , in %, shall be calculated using
c
Formula (7).
ΔΔTT =× 100 − ΔΔTT/ (7)
ce bb
where
ΔT is the temperature difference between the hot and cold sides of the glass surface at the begin-
b
ning of the steady-state temperature condition at the test, in °C;
ΔT
is the temperature difference between the hot and cold sides of the glass surface at the end of
e
the steady-state temperature condition at the test, in °C.
If the calculated value of ΔT during the test of one or more of the test specimens exceeds 10 %, the
c
relevant set of specimens shall fail the test. Breakage due to laboratory handling is not considered as
test failure. Specimens broken due to laboratory handling shall be replaced and the measurement shall
be repeated.
NOTE The most likely failure mode under this test is mechanical failure leading to loss of vacuum. This is
detectable as a significant decrease in the temperature difference across the test specimen.
5 Test report
The test report shall contain the following items:
a) the international Standard used (including year of publication);
b) identification of the specimens:
— specimen description (e.g. manufacturer’s name, product name or other reference),
— length (mm),
— width (mm), and
— nominal thickness (mm);
c) description of the test apparatus, including:
— manufacturer’s name and model, if using a commercially-available apparatus,
— inside dimensions of the chamber, i.e. height, width and depth (mm), and
— dimensions and material of the heat transfer control board located inside the chamber, if used
(mm);
d) measurement and calculation results of
2 2
— the U-value [W/(m ·K)] and thermal resistance [m ·K /W] of each specimen,
— the average, the minimum and the maximum temperature difference (°C) between the hot side
and the cold side glass surfaces during the steady-state part of the test,
2
— the calculated heat transfer coefficient [W/(m ·K)] on the hot side glass surface h and the
hot
cold side of the glass surface h , and
cold
— the calculated proportional change of the temperature difference of the hot and the cold side of
each specimen at the beginning and the end of the steady-state temperature condition ΔT (%);
c
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ISO 19916-3:2021(E)
e) the evaluation result: pass or fail of the tests;
f) any deviations from this document which may have affected the result;
g) the date of the test.
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ISO 19916-3:2021(E)
Annex A
(informative)
Guideline for the test apparatus
A.1 General
This annex provides guidelines to make the test conditions suitable for the requirements in this
document.
Circulating air within the chamber can lead to a large heat transfer coefficient at the surface of the
specimen. This heat transfer coefficient can be controlled by inserting a heat transfer control board
between the circulating air and the specimen so that air does not directly flow against the vacuum
insulating glass specimen.
A.2 Guidelines
A.2.1 Option 1
The heat transfer control board allows a small amount of forced convection at the surface of the
specimen.
The dimensions of the heat transfer control board depend on the nature of the forced convection within
the chamber. For example, in case that circulating air flows from top to bottom, the board should be
sealed against the inside surfaces of the apparatus at the top and bottom so that the air does not flow
easily into the space between the board and the specimen. There should be gaps between the board and
the chamber on both sides.
A possible dimension would be a heat transfer control board having 15 mm to 50 mm gap between
the chamber wall and around 100 mm distant from the vacuum insulating glass specimen surface. An
example of the apparatus is shown in Figure A.1.
The board should be painted black on the surface facing to the specimen so that radiative heat transfer
is enhanced.
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ISO 19916-3:2021(E)
Key
1 vacuum insulating glass specimen
2 heat transfer control board
3 cooling or heating chamber
4 air circulation
Figure A.1 — Example of option 1
A.2.2 Option 2
For an apparatus in which there is negligible forced air flow at the surface of the specimen and sufficient
natural convective heat transfer is established at this surface, the heat transfer board is not necessary.
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ISO 19916-3:2021(E)
Annex B
(informative)
Stress induced in the glass sheets of vacuum insulating glass under
temperature differences
B.1 General
A temperature difference across a vacuum insulating glass specimen causes the hot glass sheet to
expand relative to the cold sheet. The rigid edge seal prevents relative movement of the sheets at
the edges. This produces mechanical stresses in the sheets and causes the structure to bend. These
stresses can be analysed using analytic and finite element modelling methods. This Annex presents
results of the nature and magnitude of the stresses obtained with both these modelling approaches and
discusses the different physical mechanisms that affect them. The results of the modelling approaches
were validated through systematic measurements performed on VIG units exposed to a well-defined
thermal load.
B.2 Modelling conditions
The temperature difference across a vacuum insulating glass is established in the modelling
configurations by locating the specimen between a hot environment at temperature T and a cold
H
environment at temperature T . The heat transfer coefficients between the hot and cold environments
C
and the corresponding glass surfaces are h and h respectively. Heat transfer between the hot and
1 2
cold environments beyond the vacuum insulating glass is prevented by a surrounding thermally
insulating baffle.
The configuration used to apply the thermal difference across a VIG unit should establish a stress
distribution over the glass panes that is close to that which would be observed in a typical window
installation. Primarily, this means that the heat transfer processes at the glass, on the hot and cold
sides, should at least be a combination of heat flow due to natural convection and radiation. There is
sometimes an extra convective component in practical installations due to forced air flow (wind) on
the cold side. However, in the practical test specified in this document, it is convenient to use equal heat
2
transfer coefficients on both glass sheets, to within an acceptable limit (that is, 8,0 ± 2,0 W/(m ·K)).
This reduces the complexity in the setup and reduces possible inconsistent outcomes between tests. As
discussed in the following sections, choice of the heat transfer coefficients can, by a significant margin,
affect stress levels. Nevertheless, the variations in stress (including the origin of the stress components)
are well understood and can be well predicted through analytical solutions.
Figure B.1 is a schematic diagram of a vacuum insulating glass specimen defining symbols for the
parameters used in this Annex.
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ISO 19916-3:2021(E)
Key
t glass thickness (mm)
L specimen size (mm)
w width of edge seal (mm)
1 vacuum layer
2 glass sheets
3 edge seal
Figure B.1 — Schematic diagram of a vacuum insulating glass specimen
As is conventional, the surfaces of the glass sheets are denoted Surface 1 to 4 from the cold side to the
hot side. Compressive stress is written as negative and tensile stress as positive.
The numerical results of modelling presented in this Annex are for an unconstrained vacuum insulating
glass specimen having properties given in Table B.1, under the thermal conditions given in Table B.2.
NOTE In both Tables B.1 and B.2, parameters that are denoted * are varied in some of the data presented
bel
...
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