EUROPEAN STANDARD
NORME EUROPEENNE
EUROPAISCHE NORM
EN 1279-1
July 2018
ICS 81.040.20
Supersedes EN 1279-1:2004
English Version
Glass in Building - Insulating glass units - Part 1:
Generalities, system description, rules for substitution,
tolerances and visual quality
Verre dans la construction - Vitrage isolant - Partie
1 : Generalites, description du systeme, regles
de substitution, tolerances et qualite visuelle
Glas im Bauwesen - Mehrscheiben-Isolierglas
- Teil 1: Allgemeines, Systembeschreibung,
Austauschregeln, Toleranzen und visuelle Qualitat
This European Standard was approved by CEN on 9 March 2018.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving
this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical
references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre
or to any CEN member.
This European Standard exists in three official versions (English, French, German]. A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark,
Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain,
Sweden, Switzerland, Turkey and United Kingdom.
© 2018 CEN
All rights of exploitation in any form and by any means reserved
worldwide for CEN national Members
Ref. No. EN 1279-1:2018: E
EN 1279-1:2018 (E)
Contents
Page
European foreword................................................................................................................................................... iii
1
Scope...................................................................................................................................................................4
2
Normative references....................................................................................................................................4
3
Terms and definitions................................................................................................................................... 5
4
Symbols and abbreviations for edge seal............................................................................................ 12
5
Requirements................................................................................................................................................12
5.1
General....................................................................................................................................................................12
5.2
Glass panes/components................................................................................................................................13
5.2.1
General...................................................................................................................................................13
5.2.2
Basic glasses........................................................................................................................................13
5.2.3
Special basic glasses.........................................................................................................................13
5.2.4
Strengthened glasses.......................................................................................................................13
5.2.5
Thermally toughened safety glasses.........................................................................................14
5.2.6
Laminated glasses.............................................................................................................................14
5.2.7
Coated glasses....................................................................................................................................14
5.2.8
Surface worked glass.......................................................................................................................14
5.2.9
Curved glass........................................................................................................................................ 14
5.3
Cavity fillings........................................................................................................................................................14
5.4
Cavity inserts........................................................................................................................................................15
5.5
Shapes......................................................................................................................................................................15
6
Requirements................................................................................................................................................15
6.1
Durability of insulating glass units.............................................................................................................15
6.2
Optical and visual quality of the insulating glass unit........................................................................16
6.3
Dimensional tolerances................................................................................................................................... 16
6.3.1
General...................................................................................................................................................16
6.3.2
Height and width of the unit........................................................................................................ 17
6.3.3
Thickness tolerances along the periphery of the unit...................................................... 17
Annex A (normative) System description of insulating glass units............................................................19
Annex B (normative) Examples of insulating glass unit systems.............................................................. 20
Annex C (informative) Compatibility of components within an insulating glass unit system......... 25
Annex D (normative) Rules to substitute materials and components, possible changes
within components and addition in the system description.........................................................27
Annex E (informative) Edge seal strength comparison in case of substituting outer sealant...........32
Annex F (normative) Visual quality of insulating glass units.......................................................................33
Annex G (informative) Other visual aspects of insulating glass units....................................................... 37
Bibliography................................................................................................................................................................39
ii
EN 1279-1:2018 (E)
European foreword
This document (EN 1279-1:2018) has been prepared by Technical Committee CEN/TC 129 “glass in
building”, the secretariat of which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2019 and conflicting national standards shall
be withdrawn at the latest by January 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 1279-1:2004.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
The main changes in comparison with the previous edition include:
a)
Example of system descriptions was added;
b) Annex B: examples of IGU systems were transferred from part 6;
c)
Annex C compatibility of components was added;
d) Annex D: rules to substitute materials and components were revised and combined in this part;
e)
Annex F: visual appearance requirements were added.
EN 1279, Glass in Building - Insulating glass units consists of the following parts:
—
Part 1: Generalities, system description, rules for substitution, tolerances and visual quality;
—
Part 2: Long term test method and requirements for moisture penetration;
—
Part 3: Long term test method and requirements for gas leakage rate and for gas concentration
tolerances;
—
Part 4: Methods of test for the physical attributes of edge seal components and inserts;
—
Part 5: Product standard;
—
Part 6: Factory production control and periodic tests.
This standard is written on the assumption of a 25 year period of use for IGUs.
No warranty can be derived thereof for the variety of different IGU designs, manufacturing procedures
and particularly with regard to glazing situations. To ensure the full suitability and durability of new
IGU designs or special product variants additional tests of components and/or IGUs may be required.
This means, that the described test procedures and all requirements of this standard, including
factory production control, were worked out with the understanding that all values for characteristic’s
performances can be kept under relevant glazing situations in window and facades for this period
without significant change.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
the United Kingdom.
iii
EN 1279-1:2018 (E)
1
Scope
This document (all parts) covers the requirements for insulating glass units. The main intended uses
of the insulating glass units are installations in windows, doors, curtain walling, bonded glazing for
doors, windows and curtain walling, roofs and partitions.
The achievement of the requirements of this standard indicates that insulating glass units fulfil the
needs for intended use and ensures by means of the evaluation of conformity to this standard that,
visual, energetic, acoustic, safety parameters do not change significantly over time.
In cases where there is no protection against direct ultraviolet radiation or permanent shear load on
the edge seal, as in bonded glazing for doors, windows and curtain walling systems, it is essential to
follow additional European Technical Specifications (see EN 15434, EN 13022-1 and prEN 16759).
Insulating glass units that are intended for artistic purposes (e.g. lead glass or fused glass) are excluded
from the scope of this standard.
Vacuum insulating glass is not covered by this standard (see ISO DIS 19916-1).
Glass/plastics composites are under the scope as long as the surface of contact with sealants is a
glass component.
NOTE
For glass products with electrical wiring or connections for, e.g. alarm or heating purposes, other
directives, e.g. Low Voltage Directive, may apply.
This European Standard gives definitions for insulating glass units and covers the rules for the system
description, the optical and visual quality and the dimensional tolerances thereof and describes the
substitution rules based on an existing system description.
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.
EN 572-1, Glass in building — Basic soda lime silicate glass products — Part 1: Definitions and general
physical and mechanical properties
EN 572-2, Glass in building — Basic soda lime silicate glass products — Part 2: Float glass
EN 572-3, Glass in building — Basic soda lime silicate glass products — Part 3: Polished wired glass
EN 572-4, Glass in building — Basic soda lime silicate glass products — Part 4: Drawn sheet glass
EN 572-5, Glass in building — Basic soda lime silicate glass products — Part 5: Patterned glass
EN 572-6, Glass in building — Basic soda lime silicate glass products — Part 6: Wired patterned glass
EN 572-8, Glass in building — Basic soda lime silicate glass products — Part 8: Supplied and final cut sizes
EN 1279-2:2018, Glass in building — Insulating glass units — Part 2: Long term test method and
requirements for moisture penetration
EN 1279-3:2018, Glass in building — Insulating glass units — Part 3: Long term test method and
requirements for gas leakage rate and for gas concentration tolerances
EN 1279-4:2018, Glass in building — Insulating glass units — Part 4: Methods of test for the physical
attributes of edge seal components and inserts
EN 1279-5:2018, Glass in building — Insulating glass units -Part 5: Product standards
4
EN 1279-1:2018 (E)
EN 1279-6:2018, Glass in building — Insulating glass units — Part 6: Factory production control and
periodic tests
EN ISO 12543-1, Glass in building — Laminated glass and laminated safety glass — Part 1: Definitions and
description of component parts (ISO 12543-1)
EN 13022-1, Glass in building — Structural sealant glazing — Part 1: Glass products for structural sealant
glazing systems for supported and unsupported monolithic and multiple glazing
ISO 11485-1, Glass in building - Curved glass - Part 1: Terminology and definitions
ISO 11485-2, Glass in building - Curved glass - Part 2: Quality requirements
3
Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
insulating glass unit
IGU
assembly consisting of at least two panes of glass, separated by one or more spacers, hermetically
sealed along the periphery, mechanically stable and durable (as specified in 6.1)
3.1.1
IGU type A
IGU, when used for installation without permanent shear load in the sealant and protected against
direct UV exposure on edge seal
3.1.2
IGU type B
IGU, when used for installation with at least one edge not completely protected against direct UV
radiation without permanent shear load in the sealant
3.1.3
IGU type C
IGU when used for installation as bonded glazing for doors, windows and curtain walling with possible
permanent shear load on edge sealant with or without direct UV radiation exposure
Note 1 to entry: Permanent shear load can be avoided by mechanical support to carry the weight.
Note 2 to entry: For IGU type B and C additional requirements in accordance with EN 15434 and
EN 13022-1 may apply.
3.2
bonded glazing for doors, windows and curtain walling
assembly in which glass products are fixed to the structural seal frame by means of a sealant that
has been shown to be capable of withstanding the load actions applied to the glass products of the
structural seal frame
NOTE Bonded glazing for doors, windows and curtain walling (see prEN 16759) was previously called structural
sealant glazing (SSG) and is still used in some already published standards.
5
EN 1279-1:2018 (E)
3.3
system
range of insulating glass units with a common edge seal design, edge seal materials and edge seal
components as described in the system description, the range having a similar edge seal performance
NOTE Examples of edge seal performances are moisture penetration index, gas leakage rate.
3.4
system description
description of components and the edge seal of the insulating glass unit in terms relevant to
identification, and in terms relevant to edge seal performance, e.g. moisture penetration index,
gas loss rate
NOTE See Annex A .
3.5
permeation geometry
geometry of that part of the edge seal of the insulating glass unit through which the moisture and gas
transmission takes place
NOTE For example see Figure 1.
3.6
cross-over stress
sealant tensile strength value at which its stress/strain curve crosses the line joining a stress of
0,50 MPa and a strain of 50 %
NOTE Value is determined following EN 1279-4:2018, Annex A.
3.7
cavity
gap between the panes of an insulating glass unit
3.8
dehydrated air or gas
air or other gas with a low water vapour partial pressure which, when introduced into the cavity, avoid
the risk of condensation in the cavity
NOTE In all parts of EN 1279, the word “gas” refers to other gases or mixture of gases rather than air.
3.9
desiccant
component added to the system to absorb or adsorb immersing water vapour in the cavity over time
6
EN 1279-1:2018 (E)
3.10
edge seal
assembled edge of an insulating glass unit, designed to ensure that moisture and gas transmissions
between the inside and outside of the unit are limited, with a certain mechanical strength, and with a
certain physical and chemical stability
3.11
sealant
polymer material that, after application, has sufficient mechanical and physical properties of cohesion
and of adhesion to glass and/or spacer for use in edge seals
3.12
hot applied outer sealant
polymer material where an elevated temperature is required for application that, after application, has
sufficient mechanical and physical properties of cohesion and of adhesion to glass and/or spacer for use
in edge seals
3.13
double/dual seal system
edge seal system made of at least an inner sealant placed towards the cavity of the IGU and an outer
sealant in contact with the environment outside the IGU
3.14
single seal system
edge seal system made of one single sealant
3.15
spacer
component used to separate the panes and control the width of the cavity at the edge of the
insulating glass unit
NOTE The main families of spacers are given in Figure 2.
7
EN 1279-1:2018 (E)
Figure 2 — Main families of spacers
3.16
hollow spacer
spacer intended to be filled with desiccant
3.17
rigid spacer frame
set of hollow spacers, that provide enough rigidity to be preassembled prior to application and applied
against one pane of the insulating glass unit before the assembly
NOTE examples of rigid spacer frame are a frame bent with joint piece or connected with corner keys, or a
welded frame.
3.18
hollow metallic spacer
hollow spacer, painted or not, where at least 1/4 of the inner sealant adhesion height r (see Figure 3)
and all of the contact surface with outer sealant shall be metallic adhesion surface (see 3.23)
3.19
joint piece
piece that connects parts of a spacer
3.20
corner key
joint piece that acts as a corner of the spacer frame
8
EN 1279-1:2018 (E)
3.21
hot applied flexible spacer
polymer-based spacer which is applied at elevated temperature
NOTE this spacer can be either prefabricated or extruded directly onto the glass surface.
3.22
prefabricated flexible spacer
polymer based flexible spacer which is supplied as a profile to the IGU manufacturerNotel to entry: this
spacer can either be hot applied or cold applied.
3.23
adhesion surface
contact surface between spacer and one or both sealant(s)
3.24
metallic adhesion surface
spacer adhesion surface made of rolled or extruded aluminium, galvanised steel, stainless steel, without
organic surface treatment
NOTE Organic surface treatments are painting, organic coating, organic film, or organic overspray.
3.25
insert
constituent included in the cavity not directly in contact with the sealants of the edge seal
NOTE The permeation geometry can be modified as fixings or connections of the inserts may be in contact with
the edge seals.
3.26
U-channel spacer
spacer made of a U-shaped metal strip generally filled with a desiccant matrix
3.27
desiccant matrix
materials based on a polymer containing desiccant placed in a U-channel spacer for the purpose to keep
the cavity of the insulating glass unit dry
3.28
desiccant cartridge
container with desiccant, placed somewhere in the cavity
3.29
leaded light strip
lead strip usually self-adhesive used on surface 1 and/or 2 of the insulating glass unit to simulate leaded
light, traditional or modern stained glass effects
3.30
edge deletion
process to remove the coating at the edge of a coated glass, which is intended to be the adhesion surface
of the sealant(s)
3.31
external condensation
condensation appearing on the glass panes of an insulating glass unit either on the room side surface or
on the external surface
3.32
internal condensation
condensation appearing on the glass panes within a cavity of an insulating glass unit
9
EN 1279-1:2018 (E)
3.33
absolute limit
value of a parameter, given in the system description, which when exceeded requires remedial action in
manufacturing, and removal of products from production for repair or destruction
NOTE For system description, see Annex A .
3.34
action limit
value of a parameter, given in the system description, which when exceeded requires remedial action in
manufacturing
NOTE For system description, see Annex A.
3.35
spot fault
spherical or semi spherical disturbance of the visual transparency looking through the glass
NOTE It can be a solid inclusion, a gaseous inclusion, a pinhole in a coating or a spot defect in a laminated glass.
3.36
halo
area locally distorted, generally around a point defect when the defect is included in the glass pane
3.37
residue
residue is a material that remain on the glass surface, that can have the form of spot or patch
NOTE It is usually made of the seal material.
3.38
linear/extended faults
faults, which can be on or in the glass, in the form of deposits, marks or scratches that occupy an
extended length or area
3.39
stain
defect larger than punctual defect, often irregularly shaped, partially of mottled structure
3.40
cluster
accumulation of very small defects giving the impression of stain
3.41
edge defect
defects which can occur on the edge of a cut size piece in the form of entrant and emergent faults
and / or bevels
3.42
misalignment
displacement of the edges of the glass during the manufacture of insulating glass unit
3.43
water vapour transmission rate
WVTR (g • m-2 • d-1)
quantity of water vapour steadily transmitted through a 2 mm sealant film at specified conditions of
temperature and water vapour concentration
NOTE Water vapour transmission rate (WVTR) was called moisture vapour transmission rate (MVTR) in the
previous version of the standard.
10
EN 1279-1:2018 (E)
3.44
gas permeation rate
GPR (g • m-2 • d-1)
quantity of gas, steadily transmitted through a 2 mm sealant film at specified conditions of temperature
and gas concentration
3.45
standard laboratory conditions
ambient temperature of (23 ± 2) °C and relative humidity of (50 ± 5) %
3.46
gas
chemical compound or element in gaseous state
NOTE In the context of this standard gas is all gas other than air.
3.47
standard moisture adsorption capacity
Tc (%)
Total capacity of a desiccant material to adsorb moisture at specified conditions
NOTE Tc is expressed as the sum of AWAC and LOI following EN 1279-4:2018, Annex E.
3.48
moisture penetration index
I (%)
amount of available moisture adsorption capacity consumed
3.49
available water adsorption capacity
AWAC (%)
quantitative determination of the capacity of a desiccant to adsorb water under specified conditions
NOTE AWAC is expressed as the relative weight percentage increase due to water adsorption following
EN 1279-4:2018, Annex E.
3.50
loss on ignition
LOI (%)
quantitative determination of the relative weight loss of a desiccant under specified conditions
NOTE LOI is expressed as the relative weight percentage decrease due to exposure in air at 540°C following
EN 1279-4:2018, Annex E
3.51
gas-filled insulating glass units
insulating glass unit in which the cavity is filled with gas(es) usually for improving thermal insulation
3.52
gas concentration
ci (%)
percentage by volume of gas in the cavity
NOTE gas concentration is determined by EN 1279-3 testing
3.53
gas leakage rate
Li (%.a-1)
gas volume leaking from insulating glass unit given in percentage of volume per year at 20 °C
11
EN 1279-1:2018 (E)
4
Symbols and abbreviations for edge seal
The edge seal is characterized by its geometry and when relevant by the weight R of inner sealant per
length (g/m). An example is given in Figure 3.
Key
1
cavity
2
inner sealant
3
outer sealant
4
spacer, containing desiccant
r
average height of the inner sealant on glass surface
s
average height of outer sealant on glass surface
t
height of spacer
u
average effective height of outer sealant on the back of the spacer
v
width of spacer
w
concavity of outer seal
d
total thickness of IGU
Figure 3 — Example of edge seal dimensions
5
Requirements
5.1 General
The great number of possible different IGUs allow for a distinction to be made between systems, based
on common edge seal design, edge seal materials and other edge components. For conformity control
purposes, the manufacturer shall describe his system in a system description, which will be a part of
the factory production control documentation. See also Annex A, Annex B and EN 1279-6:2018.
12
EN 1279-1:2018 (E)
The rules for the system description are given in Annex A. It contains mainly a list of the applied edge
seal materials and components, the nominal edge seal dimensions of the finished product, the action
limits and the absolute limits.
Insulating glass unit systems can vary in the materials listed below, the limits in height, width, cavity
width, glass thickness and number of cavities. These lists are not exhaustive.
It is the responsibility of the manufacturer to ensure that the compatibility of materials within an
insulating glass system has been verified (see Annex C).
The possibility of substitution of different materials and other components are given in Annex D (see
also Annex E).
5.2 Glass panes/components
5.2.1
General
Glass substrates used for the production of insulating glass units:
— shall be covered by Harmonized European Specifications (as defined in Regulation EU 305/2011) as
listed below, or
— if not covered by Harmonized European Specifications, demonstration shall be made that those
glasses have a chemical composition and a mechanical stability over time equivalent to the
requirements of the relevant standard listed.
5.2.2
Basic glasses
These are glass products manufactured from soda lime silicate glass in accordance with EN 572-1 and
consist of the following:
—
Float glass
EN 572-2
—
Polished wired glass
EN 572-3
—
Drawn sheet glass
EN 572-4
—
Patterned glass
EN 572-5
—
Wired patterned glass
EN 572-6
—
Supplied and final cut sizes
EN 572-8
5.2.3
Special basic glasses
These are glass products manufactured from a variety of compositions, which are in accordance with
appropriate European Standards, and consist of the following:
—
Borosilicate glass
EN 1748-1-1
—
Glass ceramics
EN 1748-2-1
—
Alkaline earth silicate glass
EN 14178-1
—
Alumino silicate glass
EN 15681-1
5.2.4
Strengthened glasses
These are soda lime silicate glasses that have been strengthened by thermal or chemical means and
are as follows:
13
EN 1279-1:2018 (E)
—
Heat strengthened
EN 1863-1
—
Chemically strengthened
EN 12337-1
5.2.5
Thermally toughened safety glasses
These are glasses that have been toughened by thermal treatment and are as follows:
— Thermally toughened soda lime silicate safety glass
EN 12150-1
— Thermally toughened borosilicate safety glass
EN 13024-1
—
Heat soaked thermally toughened soda lime silicate safety glass
EN 14179-1
— Thermally toughened alkaline earth silicate safety glass
EN 14321-1
—
Heat soaked thermally toughened alkaline earth silicate safety glass EN 15682-1
5.2.6
Laminated glasses
These are glasses that are in accordance with EN ISO 12543-1 and consist of the following:
—
Laminated glass
EN ISO 12543-3
—
Laminated safety glass
EN ISO 12543-2
5.2.7
Coated glasses
—
coated glass
EN 1096-1
A list of coatings allowed to be used in direct contact with certain sealant(s) shall be established by and
obtained from the coated glass manufacturer. Further layer combinations or coatings may be added to
this list when evaluated in accordance with EN 1279-4:2018, Annex B.
If a combination coating / sealant is not in that list, the insulating glass unit manufacturer shall not use
that sealant in direct contact with that coating,
Some coatings are not allowed to be used in direct contact with a sealant, whatever the sealant. In that
case, the coating shall be deleted at the edges of the coated glass.
5.2.8
Surface worked glass
— Surface worked glass (e.g. sand blasted, acid etched).
The glass panes, processed or unprocessed, may be:
— transparent, translucent or opaque;
— clear or tinted.
5.2.9
Curved glass
—
Curved glass ISO 11485, all relevant parts
5.3 Cavity fillings
The cavity between two panes may be filled with air and/or gas.
14
EN 1279-1:2018 (E)
5.4
Cavity inserts
The cavity may contain inserts (e.g. plastic film or sheet, Georgian bars, blind, etc.) which shall meet
the requirements of the fogging test. The volatile content shall be determined when relevant (see
EN 1279-4:2018).
5.5
Shapes
The panes may have any shape.
6
Requirements
6.1 Durability of insulating glass units
Products intended to belong to the insulating glass unit system shall have their durability being ensured
by the following:
— the requirements of EN 1279-5:2018, 4.2.2.15 being followed;
— the manufacturing process respecting EN 1279-6:2018.
These tests are deemed to evaluate the performance of the complete sealing barrier of a multi-paned
insulating glass unit. Manufacturing insulating glass units with special sizes and/or construction which
creates higher load in the system may require special consideration for design (e.g. for triple glazing):
— when asymmetrical or thick panes construction are used the tensile load on the sealant increases;
— when edge length is < 0,6 m the tensile load on the sealant increases significantly;
— when the cavity thickness is > 18 mm the tensile load on the sealant increases significantly.
In these cases, a calculation of the edge seal tensile load should be made using prEN 16612:-Χ, Annex B.
Calculation is made with climate load only. If the calculation result is higher than 1,3 N/mm the
insulating glass unit edge seal design should be adjusted.
NOTE
Some indicative examples of tensile load in the sealant are given in Table 1 and Figure 3. They refer to
the boundary condition of EN 1279-2:2018 test (testing temperature: 58 °C, manufacturing temperature: 15 °C).
These values are defined without altitude variation.
Table 1 — Comparative edge seal maximum tensile load in insulating glass units
Insulating glass unit
design (dimension of
352x502 mm)
Edge seal Maximum ten­
sile load (N/mm)
4/12/4
1,0
4/12/4/12/4
1,3
4/18/4/18/4
1,6
4/16/4
1,0
1) Under preparation. Stage at the time of publication: prEN 16612:2017.
15
EN 1279-1:2018 (E)
x
length of the side (m)
y
maximum tensile load (N/mm)
Figure 4 — Tensile load in insulating glass units depending on the design and the short side
(ratio of sides is 1:3)
NOTE
The maximum load values cannot be recalculated to maximum tensile load within the edge
seal components.
Substitution of materials and of components shall maintain the conformity of the system with the
definition of insulating glass units. The relevant rules are summarized in Tables D.1 to D.7, together with
the validation methods. When meeting these requirements, the substituting materials and components
shall be added to the system description.
Curved insulating glass units according to ISO 11485-1 comply with this standard without having to
undergo additional tests provided that non curved insulating glass unit with the same system complies
to EN 1279. In this case special attention shall be addressed to the design of the seal system.
6.2
Optical and visual quality of the insulating glass unit
Optical and visual quality requirements for insulating glass units are described in Annex F.
NOTE
Other visual aspects are described in Annex G.
6.3 Dimensional tolerances
6.3.1
General
The following tolerances are based on the tolerances for single panes of glass given in the European
Standards listed in 5.2, and offer the worst-case situations. Narrowing these tolerances can be a subject
of contractual agreement between the insulating glass unit manufacturer and his glass supplier and/or
16
EN 1279-1:2018 (E)
his customer, or be in common usage in a local market. Where narrower tolerances are adopted, they
shall be quoted in the insulating glass unit system description and/or in the manufacturer's quality
manual, or in specific cases, cross-referenced to the particular contract details.
For curved glass ISO 11485-2 applies.
6.3.2
Height and width of the unit
When insulating glass unit dimensions are quoted for rectangular panes, the first dimension shall be
the width, B, and the second dimension the height, H, as shown in Figure 4. It shall be made clear which
dimension is the width, B, and which is the height, H, when related to its installed position.
NOTE
For insulating glass units containing patterned glass panes, it is advised to specify the direction of the
pattern relative to one of the dimensions.
a:
Β
a:
Β
Figure 5 — Examples of width and heignt relative to the pane shape
The dimensional tolerances shall be part of the system description and subject to the factory production
control in relevant clauses of EN 1279-6:2018. Guidance on dimensional tolerances are given in Table 2.
Table 2 — Guidance on dimensional tolerances of insulating glass units
Double / triple IGU
Tolerances on B
and H
Misalignment
all panes < 6 mm, and (B and H) < 2 000 mm
± 2 mm
< 2 mm
6 mm < thickest pane < 12 mm, or 2 000 mm < (B or H) < 3 500 mm
±3 mm
< 3 mm
3 500 mm < (B or H) < 5 000 mm and thickest pane < 12 mm
±4 mm
< 4 mm
1 pane > 12 mm, or (B or H) > 5 000 mm
±5 mm
< 5 mm
Thicknesses are nominal thickness.
Special dimensions and tolerances may be agreed.
6.3.3
Thickness tolerances along the periphery of the unit
The actual thickness shall be measured between the outside glass surfaces of the unit, at each corner
and at the approximate centre points of the edges. The values shall be measured to 0,01 mm accuracy
and given to the nearest 0,1 mm. The measured thicknesses shall not vary from the nominal thickness
given by the manufacturer of the insulating glass units by more than the tolerances shown in Table 3.
17
EN 1279-1:2018 (E)
Table 3 — Thickness tolerances on the insulating glass units
Glazing
Pane
IGU thickness tolerance a
double glazing
All panes are annealed float glass
±1,0 mm
At least one pane is laminated, pat­
terned or not annealed glass
±1,5 mm
triple glazing
All panes are annealed float glass
±1,4 mm
At least one pane is laminated, pat­
terned or not annealed glass
+2,8 mm/ -1,4 mm
a
If one glass component has a nominal thickness greater than 12 mm in the case of annealed or toughened glass, or
20 mm in the case of laminated glass, the insulating glass unit manufacturer should be consulted.
18
EN 1279-1:2018 (E)
System description of insulating glass units
The system description shall contain at least:
— the IGU description including edge seal design and tolerances;
— a list of components including absolute limits for tolerances.
Action limits may be included.
The component descriptions shall consist of:
a)
a drawing of a cross section of the sealed edge of the insulating glass unit to scale, with each
component numbered (an example of this is given in Figure 3, see also Annex B). When not all
components appear in the drawing, additional drawings shall be made;
b)
a list of the components according to the numbering of the detailed drawing(s), and in accordance
with the relevant examples of Annex B:
c)
a list of inserts not detailed in the drawing;
d) a record for each of the components. Each record shall contain:
— a reference to the drawing with number and functional name of the component;
— the name of supplier(s) or manufacturer(s);
— a general description of the material(s) used for the component (e.g. desiccant), followed where
appropriate by some more detailed information (e.g. molecular sieve 3 A);
— a drawing with dimensions related to the permeation geometry, when relevant.
Annex A
(n o rm a tiv e )
19
EN 1279-1:2018 (E)
Examples of insulating glass unit systems
B.1
General
This annex gives examples of IGU systems commonly available. EN 1279-6:2018 gives the factory
production control related to each of them.
Depending on the system, the insulating glass unit can be either air-filled or gas-filled.
B.2
Organic sealed insulating glass units with rigid hollow spacer
Figure B.1 shows the principle of organic sealed insulating glass units with rigid hollow spacer, with
outer sealant (cold or hot applied).
Annex B
(n o rm a tiv e )
Key
1
desiccant
4
glass
2
spacer bar
5
inner sealant
3
diffusion openings
6
outer sealant
Figure B.1 — Principle of an organic sealed insulating glass units with hollow spacer
20
EN 1279-1:2018 (E)
B.3
Insulating glass units sealed by hot applied flexible spacer
incorporating desiccant
Figure B.2 shows the principle of IGU with a flexible spacer frame with a hot applied flexible spacer
incorporating desiccant.
This system may also comprise an outer sealant without desiccant and/or a permeation barrier or
spacer, incorporated or not in the organic spacer during its production.
Key
1
glass
2
hot applied flexible spacer incorporating desiccant
3
outer sealant without desiccant
4
permeation barrier or spacer
Figure B.2 — Examples of insulating glass units sealed by hot applied flexible spacer
incorporating desiccant
B.4
Insulating glass units with prefabricated flexible spacer
Figure B.3 shows the principle of insulating glass units with prefabricated flexible spacer.
Flexible spacers with pre-applied inner sealant are covered by this description.
21
EN 1279-1:2018 (E)
Key
1
2
3
4
5
glass
flexible spacer with water permeable polymer
pressure sensitive adhesive
moisture/inert gas barrier
outer sealant
Figure B.3 — Principle of an insulating glass unit with prefabricated flexible spacer
B.5
Organic sealed insulating glass units with U-channel shaped spacer
incorporating desiccant matrix
Figure B.4 shows the principle of organic sealed insulating glass units, where the spacer is a U shape
metallic spacer incorporating an extruded organic desiccant matrix.
22
EN 1279-1:2018 (E)
Key
1
spacer
2
desiccant matrix
3
glass
4
inner sealant
5
outer sealant
Figure B.4 — Principle of an organic sealed insulating glass unit with U shaped metallic spacer
incorporating an extruded organic desiccant matrix
B.6
Air filled insulating glass units sealed by a metal strip between
the glass panes
Figure B.5 shows the principle of metal sealed air-filled insulating glass units with metal strip as spacer.
23
EN 1279-1:2018 (E)
Key
1
solder
2
copper and tin layer
3
metal strip
4
dehydrated air
5
Glass
Figure B.5 — Principle of an insulating glass unit sealed by a metal strip between
the glass panes
24
EN 1279-1:2018 (E)
Compatibility of components within an insulating
glass unit system
C.1
Compatibility
The components are considered to be compatible if their interaction within the insulating glass unit
does not affect the relevant properties of the unit over the expected life time.
C.2
Diffusion and equilibrium
Some products contained in the IGU components which are not chemically bound within the matrix,
such as plasticisers, catalysts, antioxidants, light stabilizers, etc. may migrate. When components are
brought into direct contact, migration may lead to diffusion of products between components.
The speed of this diffusion will depend on the partial pressure difference, the molecular weight of
the material, the ambient temperature, the dimensions of the components, and the solubility of the
migrating products in the matrices of the components involved.
The diffusion processes come to an end, when the equilibrium of all migrating products is reached.
C.3
Contact
Direct contact occurs if two components are in contact.
Indirect contact occurs if two components have direct contact to a third material which is able to absorb
or adsorb at least one of the migrating products of one of the two components.
C.4
Interaction
Components, within a system which are brought into direct or indirect contact, exchange migrating
products due to the diffusion processes. The gain and/or loss of products cause changes in the physical
properties of one or both components, such as modulus, volume, density, viscosity, and yield value.
Whilst the changes are mainly affecting the physical properties, in some cases chemical reactions
may also occur.
The changes described above are called interaction.
C.5
Factors affecting compatibility
As a guideline some general statements can be made. It should be noted that these statements do not
replace detailed evaluation on a case to case basis.
The risk of incompatibility due to interactions increases
a)
when the amount of possible migrating products in the components increases;
b)
at higher temperatures;
c)
with higher mass ratio of components in contact;
Annex C
(in fo rm a tiv e )
25
EN 1279-1:2018 (E)
d) with larger relative contact surface area between the components;
e)
with lower surface tension of the migrating products.
The impact on properties of the components within IGUs is most critical:
f)
on hot applied components such as primary sealants (PIB) or hot melts;
g) where volume change (swelling or shrinkage) causes multi-axial tension such as in the case of
laminated glass interlayers;
h)
where wetting properties are changed by products such as silicone or unsaturated plant oils.
NOTE
For test methods, it is advised to refer to testing guides, i.e. [1], [2], and EN 15434:2006+A1:2010, Clause 7.
26
EN 1279-1:2018 (E)
Rules to substitute materials and components, possible changes
within components and addition in the system description
Annex D
(n o rm a tiv e )
D.1
General comments
System description, quality manual and Factory Production Control (FPC) shall be updated whenever a
substitution or change is undertaken.
The following processes on glass have no influence: thermally toughening, heat-soak thermally
toughening, heat-strengthening, chemically strengthening and lamination of glass, provided that the
adhesion surface is glass.
The chemical nature of the glass component (i.e. soda lime glass, borosilicate glass, glass ceramic,
alkaline earth silicate glass, alumino silicate glass) has no influence on the durability of the IGU and
substitution is allowed without condition.
Substitution is allowed for more than one component according to the tables.
What is not mentioned in these substitution rules is not allowed and a new type test is required.
These changes are valid for all types of IGU (type A, B and C). In case of substitution, components shall
conform to the corresponding requirements of EN 13022-1 if applicable.
All type test reports shall also include the relevant technical information (e.g. dimensions of the seal).
D.2
Tables of possibilities to substitute materials and components, and of
possible changes within components
In the following tables, index 1 refers to the type test before substitution and index 2 refers to the type
test of the product that will substitute the initial one.
The component manufacturer's type test reports may be used to validate the substitution.
The dimensions, u, s and r, are indicated in Figure 3.
R is the mass of inner sealant per length and spacer side (g/m) .
In Tables D.1 to D.6 undated standard references mean that existing test reports obtained under the
previous version of the standard can be used.
When the tables refer to "another party", it means implicitly reference to EN 1279-5:2016, Annex D.
27
EN 1279-1:2018 (E)
Table D.1 — Substitution of outer sealant: validation methods and requirements
With:
Gas
filling
Derived requirement and validation method
Same rigid spacer
frame
Air or
gas
Type test report according to EN 1279-2 is available, e.g. from the supplier or an­
other party,
- for a spacer frame system which is allowed for substitution according to Table D.4,
and
- where the substitute outer sealant is used, and with
- u 2 > ui and/or s2 > si, and either
- 12 < 0,1 and W VTR 2 < 1,2 x W VTRi: Allowed with no restriction with regard to
EN 1279-2, or
- 0,1 < I2 < 0,2 and W VTR 2 < W VTR 1 : Allowed with no restriction with regard to
EN 1279-2
Stress/strain curve: Allowable deviation for crossover stress a c is ± 20 % or ± 0,02 MPa,
whichever is the highest, from the cross over stress 0 c of the original sealant. See
also Annex E.
All relevant parts of EN 1279-6:2018 shall be carried out.
Gas
Type test report according to EN 1279-3 is available, e.g. from the supplier or an­
other party,
- for a spacer frame system which is allowed for substitution according to Table D.4 and
- where the substitute outer sealant is used, and with
- u 2 > U1 and/or s2 > s1, and
- GPR2 < 1,2 x GPR1
Same glass coat­
ings (not edge
deleted, coatings)
Air or
gas
Type test report according to EN 1279-2 is available, e.g. from the supplier or an­
other party,
- for a spacer frame system which is allowed for substitution according to Table D.4,
and
- where the same coating is used, and
- where the substituted outer sealant is used
Substitution is allowed when complying with EN 1279-4:2018, Annex B.
Gas
Type test report according to EN 1279-3 is available, e.g. from the supplier or an­
other party,
- for a spacer frame system which is allowed for substitution according to Table D.4,
and
- where the same coating is used, and
- where the substituted outer sealant is used
- u 2 > U1 or s2 > s1
Substitution is allowed when complying with EN 1279-4:2018, Annex B.
28
EN 1279-1:2018 (E)
Table D.2 — Substitution of inner sealant: validation methods and requirements
With:
Gas
filling
Derived requirement and validation method
Type test report according to EN 1279-2 is available, e.g. from the supplier or an­
other party,
- for a spacer frame system which is allowed for substitution according to Table D.4, and
Air or
gas
- where the substitute inner sealant is used, and with
- r 2 > Γ1 or R 2 > R1, and
Same rigid spacer
frame with me-
- W VTR2 < 0,5 g.m-2.d-i. according to EN 1279-4
tallic adhesion
All relevant parts of EN 1279-6:2018 shall be carried out.
surface
Gas
Type test report according to EN 1279-3 is available, e.g. from the supplier or an­
other party,
- for a frame system which is allowed for substitution according to Table D.4 and
- where the substitute inner sealant is used, and with
- r 2 > Γ1 or R 2 > R1, and
- GPR2 < 0,060 0 gAr.m-2.day-1 according to EN 1279-4
Table D.3 — Substitution of single sealant: validation methods and requirement
With:
Gas
filling
Derived requirement and validation method
Air or
Test report according to EN 1279-4 and EN 1279-2 are available, e.g. from the sup­
plier or another party,
- for a spacer frame system which is allowed for substitution according to Table D.4, and
- where the substitute single sealant is used, and with
Same rigid spacer
frame
gas
- u 2 > U1 or s2 > S1 and
- W VTR 2 < 0,5 g.mr2.d-1. according to EN 1279-4
All relevant parts of EN 1279-6:2018 shall be carried out.
Gas
Type test report according to EN 1279-3 is available, e.g. from the supplier or an­
other party,
- for a spacer frame system which is allowed for substitution according to Table D.4, and
- where the substitute single sealant is used, and with
- u 2 > U1 or s2 > S1, and
- GPR2 < 0,0600 gAr.m-2.day-1 according to EN 1279-4
29
EN 1279-1:2018 (E)
Table D.4 — Substitution of rigid spacer frame and accessories: validation methods
and requirement
Substitution of:
Gas
filling
Derived requirement and validation method
Rigid spacer frame
with metallic adhesion
surfacea (bent spacer
by bent spacer or
corner keys by corner
keys, welded spacer by
welded spacer)
Air or
gas
Type test report according to EN 1279-2 is available, e.g. from the supplier or
another party, with
- u2 > U1 and/or s2 > s1, and
- the calculated moisture penetration index I referring to the available des­
iccant volume shall respect the requirements of EN 1279-2.
Fulfil requirement of EN 1279-6:2018, D.3.2.
Gas
Type test report according to EN 1279-3 is available e.g. from the supplier or
another party, with
- u2 > U1 and/or s2 > s1
Rigid spacer frame
with metallic adhesion
surface, with corner
keys by same spacer,
bent or welded
Air or
gas
allowed with no restriction
Gas
Short climatic test following EN 1279-6:2018, B.4.
Rigid spacer frame
with metallic adhesion
surface, with bent or
welded spacers by
same spacer with cor­
ner keys
Air or
gas
Type test report according to EN 1279-2 is available, e.g. from the supplier or
another party
- for the respective system, with
- moisture penetration index Iav < 0,15, and
- u2 > U1 and/or s2 > s1, and
- available desiccant volume with bent spacers does not exceed available des­
iccant volume with corner keys
Gas
Type test report according to EN 1279-3 is available, e.g. from the supplier or
another party, on comparable geometry.
Rigid spacer frame
with metallic adhesion
surface,
Corner keys 1 by
corner keys 2 or joint
piece 1 by joint piece 2
Air or
gas
Metal to metal: allowed with no restriction.
All other substitutions: short climatic test following EN 1279-6:2018.
Gas
Short climatic test and gas concentration according to according to EN 12 79-6:2018,
Annex B.
Rigid spacer frame
with metallic adhesion
surface,
Gas filling holes closing
material
Gas
Same gas filling holes closing material type and different supplier: allowed
with no restriction.
Different gas filling holes closing material: short clim atic test following
EN 1279-6:2018, B.4.
a
Subject to definition 3.24
Table D.5 — Substitution of glass: validation methods and requirement
Substitution of:
Gas filling
Derived requirement and validation method
Edge deleted coat­
ed glass by another
edge deleted coat­
ed glass
Air or gas
Substitution is allowed
Non edge delet­
ed coating 1 by
non-edge deleted
coating 2
Air or gas
Substitution is allowed when complying with EN 1096-2:2012, Annex F and
EN 1279-4:2018, Annex B.
Glass surface by
acid-etched sur­
face
Air and gas
Substitution is allowed only when an inner sealant is used.
30
EN 1279-1:2018 (E)
Substitution of:
Gas filling
Derived requirement and validation method
Glass surface by
enamelled (ce­
ramic frit) surface
(EN 12150-1)
Air or gas
Substitution is allowed.
Table D.6 — Substitution of desiccants: validation methods and requirement
Substitution of:
Gas
filling
Derived requirement and Validation method
Desiccant 1 by
desiccant 2
Air or
gas
Test report according to EN 1279-4:2018 for substitute desiccant is available, with
- AWAC of the substitute shall be minimum 16,0 %.
Type test report EN 1279-2 is available e.g. from the supplier or another party,
- for the same or (an)other system(s), and
- where the substitute desiccant is used.
Recalculated Moisture penetration index with available spacer volume complies
with EN 1279-2:2018.
Table D.7 — Substitution of gas: validation methods and requirement
Substitution of:
Derived requirement and Validation method
Argon by krypton
or by mixture of
both
Substitution is allowed. For calculation of U value according to EN 1279-5:2018, Annex A, a
value of 1 % shall be used for Li.
D.3
Addition of components
D.3.1 Addition of cavity inserts without change of the permeation barrier design
Inserts shall pass a fogging test in accordance with EN 1279-4:2016, Annex C and a volatile test in
accordance with EN 1279-4:2016, Annex H. Moisture which is introduced by components has to be
taken into account for the moisture penetration index.
NOTE
Fogging test and volatile test performed according to a previous version of the standard remain valid.
D.3.2 Addition of cavity inserts with change of the permeation barrier design
Type test report from supplier or another party according to EN 1279-2 and EN 1279-3 shall be required.
Inserts shall pass a fogging test in accordance with EN 1279-4:2018, Annex C and a volatile test in
accordance with EN 1279-4:2018, Annex H. Moisture which is introduced by components has to be
taken into account for the moisture penetration index.
If the sealants used in these test reports are different from those to be used, substitution rules according
to Table D.2, shall apply.
EN 1279-4:2018, Annex C and EN 1279-4:2018, Annex H shall be fulfilled in both cases.
NOTE
Fogging test and volatile test performed according to a previous version of the standard remain valid.
31
EN 1279-1:2018 (E)
Edge seal strength comparison in case of substituting
outer sealant
Annex E
(in fo rm a tiv e )
The average stress-strain profile of the test specimens in the area AOB for each corresponding
conditioning of testing (see EN 1279-4:2018, 5.2) shall be substantially the same as the profile obtained
for the original tested as a type test. The cross over at line AB in Figure E.1 shall be within ± 20 %
or ± 0,02 MPa, whichever is the highest, from the original cross over stress for each corresponding
conditioning of test.
Key
1
stress strain curve of the original sealant. Failure shall be somewhere out of triangle OAB
2
cross over stress oc
3
allowable plus deviation
4
allowable minus deviation
Figure E.1 — Illustration of the allowable deviation
32
EN 1279-1:2018 (E)
Visual quality of insulating glass units
Annex F
(n o rm a tiv e )
F.1
General
This annex applies to assessment of the visible quality of insulating glass units made of glass components
as defined in 5.2.
The optical and visual quality requirements for glass components shall be taken from the appropriate
European Standards.
Tables F.1 to E3. give the maximum allowable fault per insulating glass unit, as well as the faults that
are specific to the assembly. These tables shall not be used for insulating glass unit with at least
one component made of patterned glass, wired glass, wired patterned glass, drawn sheet glass, fire
resistant laminated glass.
The tables cover insulating glass units of types A, B and C.
F.2
Observation conditions
The panes shall be examined in transmission and not in reflection.
The discrepancies shall not be marked on the pane.
The insulating glass units shall be observed at a distance of not less than 3 m from the inside to the
outside and at a viewing angle as perpendicular to the glass surface as possible for up to one minute per
m2. The assessment is carried out under diffuse daylight conditions (e.g. overcast sky), without direct
sunlight or artificial lighting.
Insulating glass units assessed from the outside shall be examined in installed condition, taking
into consideration the usual viewing distance with a minimum of 3 m. The viewing angle shall be as
perpendicular to the glass surface as possible.
The following observation zones are defined in Figure F.1.
33
EN 1279-1:2018 (E)
Key
R
zone of 15 mm usually covered by the frame, or corresponding to the edge seal in case of unframed edge
E
zone at the edge of the visible area, with a width of 50 mm
M
main zone
Figure F.1 — Glass pane defect zones
F.3
Insulating glass unit made of two panes of monolithic glass
F.3.1
Spot faults
The maximum number of spots faults is defined in Table F.1.
Table F.1 — Allowable number of spot faults
Zone
Size of fault
(excluding
halo)
(0 in mm)
Size of the pane S (m2)
S< 1
1 < S < 2
2 < S < 3
3 < S
R
All sizes
No limitation
E
0 < 1
Accepted if less than 3 in each area of 0 < 20 cm
1 < 0 < 3
4
1 per metre of perimeter
0 > 3
Not allowed
M
0 < 1
Accepted if less than 3 in each area of 0 < 20 cm
1 < 0 < 2
2
3
5
5 + 2/m2
0 > 2
Not allowed
F.3.2
Residues
The maximum allowable number of residue spots and stains is defined in Table F.2.
34
EN 1279-1:2018 (E)
Table F.2 — Allowable number of residue spots and stains
Zone
Dimensions and type
(0 in mm)
Pane area S (m2)
S< 1
1 < S
R
All
No limitation
E
Spots 0 < 1
No limitation
Spots 1 mm < 0 < 3
4
1 per m of perimeter
Stain 0 < 17
1
Spots 0 > 3 and stain 0 > 17
maximum 1
M
Spots 0 < 1
Maximum 3 in each area of 0 < 20 cm
Spots 1 < 0 < 3
Maximum 2 in each area of 0 < 20 cm
Spot 0 > 3 and stain 0 > 17
Not accepted
F.3.3
Linear / extended fault
The maximum number of linear / extended fault is defined in Table F.3.
Hairlines scratches are allowed provided that they do not form a cluster.
Table F.3 — Allowable number of linear / extended faults
Zone
Individual lengths
(mm)
Total of individual lengths
(mm)
R
No limitation
E
< 30
< 90
M
< 15
< 45
F.4
Insulating glass units other than made of two monolithic glass panes
The allowable number of discrepancies defined in F.3. is increased by 25 % per additional glass
component (in multiple glazing or in a laminated glass component) . The number of allowable defects is
always rounded up.
EXAMPLES
—
Triple glazed unit made of 3 monolithic glass panes: the number of allowable faults of F.3 is multiplied by 1,25.
—
Double glazed unit made of two laminated glass with 2 glass components each: the number of allowable
faults of E 3 is multiplied by 1,5.
F.5
Insulating glass unit containing a heat treated glass
The visual quality of thermally toughened safety glass, with or without heat soaking and of heat
strengthened glass, when assembled in an insulating glass unit or in a laminated glass which is a
component of an insulating glass unit, shall fulfil the requirements of their respective product standard.
In addition to these requirements, for heat treated float glass, the overall bow relative to the total
glass edge length may not be greater than 3 mm per 1 000 mm glass edge length. Greater overall
bow may occur for square or near square formats (up to 1:1.5) and for single panes with a nominal
thickness < 6 mm.
F.6
Edge defects
Allowable edge defects are given in the relevant standard for each glass pane component.
35
EN 1279-1:2018 (E)
External shallow damage to the edge or conchoidal fractures which do not affect the glass strength and
which do not project beyond the width of the edge seal are acceptable.
Internal conchoidal fractures without loose shards, which are filled by the sealant, are acceptable.
F.7
Tolerance on spacer straightness
For double glazing the tolerance on the spacer straightness is 4 mm up to a length of 3,5 m, and 6 mm
for longer lengths. The permissible deviation of the spacer(s) in relation to the parallel straight glass
edge or to other spacers (e.g. in triple glazing) is 3 mm up to an edge length of 2,5 m. For longer edge
lengths, the permissible deviation is 6 mm.
Figure F.2 shows examples of deviation of spacer position.
1
spacer
2
theoretical shape of the spacer
3
theoretical position of the spacer
4
deviation
Figure F.2 — Examples of spacer deviation
F.8
Curved insulating glass units
The visual quality of curved insulating glass units and their glass components shall fulfil the
requirements of ISO 11485-1 and ISO 11485-2.
36
EN 1279-1:2018 (E)
Other visual aspects of insulating glass units
Annex G
(in fo rm a tiv e )
G.1
General
Some physical effects can occur that are visible on the glass surface and shall not be taken into account
when assessing the visual quality. They are not considered as defects.
G.2
Inherent colour
Variations in the colour impression are possible due to the iron oxide content of the glass, the
coating process, the coating itself, variation in the glass thickness and the unit construction and
cannot be avoided.
G.3
Difference in insulating glass unit colour
Facades made of IGUs incorporating coated glass can present different shades of the same colour, an
effect that can be amplified when observed at an angle. Possible causes of differences in colour include
slight variations in the colour of the substrate onto which the coating is applied and slight variations in
thickness of the coating itself.
An objective assessment of the differences in colour can be done using ISO 11479-2.
G.4
Interference effect
In insulating glass units made of float glass, interference effects may cause spectral colours to appear.
Optical interference is due to superposition of two or more light waves at a single point.
The effects are seen as variation in intensity of the coloured zones, which change when pressure is
applied to the glass. This physical effect is reinforced by the parallelism of the surfaces of the glass.
Interference effects occur at random and cannot be avoided.
G.5
Specific effect due to barometric conditions
An insulating glass unit includes a volume of air or other gas, hermetically sealed by the edge seal.
The state of the gas is essentially determined by the altitude, the barometric pressure and the air
temperature, at the time and place of manufacture. If the insulating glass unit is installed at another
altitude, or when the temperature or barometric pressure changes (higher or lower pressure), the
panes will deflect inwards or outwards, resulting in optical distortion.
G.6
Multiple reflections
Multiple reflections can occur in varying intensity at the surfaces of glass units. These reflections can
be seen particularly well if the background viewed through the glazing is dark. This effect is a physical
property of all insulating glass units.
37
EN 1279-1:2018 (E)
G.7
Anisotropy (iridescence)
Insulating glass units that contain a heat-treated glass component may show visual phenomena known
as anisotropy, see EN 12150-1, EN 1863-1.
G.8
Condensation on the external surface of the insulating glass unit
Condensation can occur on the external glass surfaces when the glass surface is colder than the
adjacent air.
The extent of condensation on the external surfaces of a glass pane is determined by the U-value, the air
humidity, air movement and the indoor and outdoor temperatures.
When the ambient relative humidity is high and when the surface temperature of the pane falls below
the ambient temperature, condensation at the glass surface occurs.
G.9
Wetting of glass surfaces
The appearance of the glass surfaces can differ due to the effect of rollers, finger prints, labels, vacuum
suction holders, sealant residues, silicone compounds, smoothing agents, lubricants, environmental
influences etc. This can become evident when the glass surfaces are wet by condensation, rain or
cleaning water.
38
EN 1279-1:2018 (E)
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39
EN 1279-1:2018 (E)
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40