oSIST prEN 16612:2013

Glass in building - Determination of the load resistance of glass panes by calculation and testing

This European Standard gives the principles of determining the load resistance of glass. It gives
-  the general method of calculation, and
-  determination of load resistance by testing for any application.
This European Standard does not determine suitability for purpose. Resistance to applied loads is only one part of the design process, which may also need to take into account
-  environmental factors (e.g. sound insulation, thermal properties),
-  safety characteristics (e.g. fire performance, breakage characteristics in relation to human safety, security).

Glas im Bauwesen - Bestimmung des Belastungswiderstandes von Glasscheiben durch Berechnung und Prüfung

Diese Europäische Norm legt die Grundsätze zur Bestimmung des Belastungswiderstands von Glas fest. Sie legt Folgendes fest:
-   allgemeine Berechnungsverfahren; und
-   Bestimmung des Belastungswiderstands jeder Anwendung durch Prüfung.
Diese Europäische Norm legt nicht die Gebrauchstauglichkeit fest. Der Widerstand gegenüber der aufgebrachten Last ist nur ein Teil des Entwurfsprozesses, bei dem auch Folgendes berücksichtigt werden muss:
-   umgebungsbezogene Faktoren (z. B. Schalldämmung, thermische Eigenschaften);
-   Sicherheitsmerkmale (z. B. Brandverhalten, Bruchverhalten in Bezug auf den Schutz von Personen, Sicherheit).

Verre dans la construction - Détermination de la résistance des feuilles de verre par calcul et par essai

La présente Norme européenne donne les principes de détermination de la résistance du verre à une charge. Elle donne :
•   la méthode générale de calcul et
•   la détermination de la résistance à une charge par des essais pour toute application.
La présente Norme européenne ne préjuge pas de l’aptitude à l’emploi. La résistance à des charges appliquées n'est qu'une partie du processus de conception, qui peut également prendre en compte :
•   les facteurs environnementaux (par exemple, les propriétés thermiques),
•   les caractéristiques de sécurité (par exemple, des caractéristiques de rupture vis-à-vis de la sécurité des personnes, de la sécurité).

Steklo v gradbeništvu - Ugotavljanje odpornosti steklenih plošč proti obremenitvi z izračunom in preskušanjem

General Information

• Status: Not Published
• Public Enquiry End Date: 29-Sep-2013
• ICS: 81.040.20 - Glass in building
• Technical Committee: STV - Steklo, svetloba in razsvetljava v gradbeništvu
• Current Stage: 98 - Abandoned project (Adopted Project)
• Start Date: 05-Oct-2015
• Due Date: 10-Oct-2015
• Completion Date: 05-Oct-2015
• Directive: 88/609/EEC - Limitation of emissions of certain pollutants into the air from large combustion plants
• Mandate: M/135 - Mandate to CEN/CENELEC concerning the execution of standardization work for harmonized standards on flat glass, profiled glass and glass block products
• Ref Project: prEN 16612 - Glass in building - Determination of the load resistance of glass panes by calculation and testing

Overview

The European Standard oSIST prEN 16612:2013, titled "Glass in building - Determination of the load resistance of glass panes by calculation and testing", provides fundamental principles for calculating and testing the load resistance of glass used in construction. Developed by CEN Technical Committee 129, this standard is crucial for engineers, architects, and product developers involved in designing glass components for buildings. It focuses on ensuring the ability of glass panes to withstand applied structural loads safely, although it does not address overall suitability for purpose, which includes factors like environmental performance or safety characteristics beyond load resistance.

Key Topics

oSIST prEN 16612:2013 covers comprehensive aspects essential for understanding and determining glass load resistance:

• General Calculation Methods
  Establishes formulas and calculation principles for stress, deflection, and strength based on recognized Eurocodes (EN 1990, EN 1991 series). These methods consider different glass types such as annealed, prestressed (thermally or chemically strengthened), laminated, and insulating glass units.

• Load Resistance by Testing
  Provides guidelines for physical testing of glass panes to determine their structural load resistance. Testing complements calculations by accounting for real-world factors such as surface conditions, load duration, and temperature effects.

• Material Properties and Factors
  Details mechanical and physical properties essential for design, such as characteristic strength values, surface profile factors, and partial material factors (γ), allowing for reliable load resistance assessments.

• Types of Glass Defined
  Defines key terms including annealed glass, prestressed glass, laminated glass, and enamelled glass, offering clarity on glass categories covered by the standard.

• Calculation for Complex Assemblies
  Includes methods for laminated glass and insulating glass units (double and triple glazed), which are commonly used in modern building envelopes to provide additional performance benefits.

• National Annex Model Proposal
  Suggests a framework for National Annexes to adjust parameters like partial material and load factors according to country-specific reliability requirements.

Applications

oSIST prEN 16612:2013 supports the design and assessment of glass in a wide range of building applications, such as:

• Facade Engineering
  Ensuring glass panels in curtain walls and window systems can safely carry imposed loads such as wind pressure, snow loads, and dead loads.

• Structural Glazing
  Calculating load resistance for glass used as structural elements or load-bearing parts in façades and skylights.

• Safety Glass Installations
  Complementing safety performance evaluations by verifying structural strength and resistance to expected mechanical stresses.

• Energy-Efficient and Insulating Glazing Units
  Designing load-bearing capabilities of multi-pane insulating glass units (IGUs) to maintain long-term structural stability while providing thermal insulation.

• Renovation and Compliance Checks
  Assessing existing glass installations for load resistance compliance as part of refurbishment or safety audits.

The standard enables consistent and reliable evaluations, facilitating safer glass use in construction and contributing to overall building performance optimization.

Related Standards

oSIST prEN 16612:2013 references several key European and international standards relevant to glass in construction, supporting a holistic approach:

• EN 1990: Basis of Structural Design - Fundamental principles for structural safety and reliability.

• EN 1991: Actions on Structures (including wind and snow loads) - Defines external loads applied to structures.

• EN 572-1: Soda Lime Silicate Glass Products - Details definitions, properties, and characteristics of basic float glass.

• EN 12150-1: Thermally Toughened Soda Lime Silicate Safety Glass - Specifies the properties of thermally toughened glass variants.

• EN ISO 12543: Laminated and Laminated Safety Glass - Defines laminated glass construction and its components.

• EN 1279: Insulating Glass Units - Provides requirements for double and triple glazing units.

• EN 14449: Laminated Glass Evaluation of Conformity - Concerns product conformity for laminated safety glass.

These standards complement oSIST prEN 16612:2013 by covering the full spectrum of physical properties, structural design, testing procedures, and product conformity necessary for responsible glass use in buildings.

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Keywords: load resistance of glass, glass in building, glass pane calculation, glass testing standards, structural glass design, annealed glass, prestressed glass, laminated glass, insulating glass units, Eurocode glass design, CEN glass standards, European glass standard

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2013
6WHNORYJUDGEHQLãWYX8JRWDYOMDQMHRGSRUQRVWLVWHNOHQLKSORãþSURWLREUHPHQLWYL
]L]UDþXQRPLQSUHVNXãDQMHP
Glass in building - Determination of the load resistance of glass panes by calculation and
testing
Glas im Bauwesen - Bestimmung des Belastungswiderstandes von Glasscheiben durch
Berechnung und Prüfung
Verre dans la construction - Détermination de la résistance des feuilles de verre par
calcul et par essai
Ta slovenski standard je istoveten z: prEN 16612
ICS:
81.040.20 Steklo v gradbeništvu Glass in building
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2013
ICS 81.040.20
English Version
Glass in building - Determination of the load resistance of glass
panes by calculation and testing
Verre dans la construction - Détermination de la résistance Glas im Bauwesen - Bestimmung des
des feuilles de verre par calcul et par essai Belastungswiderstandes von Glasscheiben durch
Berechnung und Prüfung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 129.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16612:2013: E
worldwide for CEN national Members.

Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .7
4 Symbols and abbreviations .9
5 Requirements . 14
5.1 Basis of determination of load resistance of glass . 14
5.2 General requirements . 15
5.3 Material partial factor . 15
5.4 Process of determining the load resistance of glass . 15
6 Mechanical and physical properties of glass . 16
6.1 Values . 16
6.2 Approximate values . 16
7 Actions . 16
7.1 Assumptions related to the actions and combinations of actions . 16
7.2 Combinations of actions . 16
8 Strength and stress . 18
8.1 Design value of strength for annealed glass . 18
8.1.1 Formulae . 18
8.1.2 Glass surface profile factor . 18
8.1.3 Factor for duration of load . 19
8.2 Design value of strength for prestressed glass . 20
8.2.1 Formula . 20
8.2.2 Characteristic bending strength . 21
8.2.3 Strengthening factor . 21
9 Calculation principles and conditions . 21
9.1 General method of calculation . 21
9.1.1 Design load . 21
9.1.2 Stress and deflection calculation. 22
9.1.3 Design value of strength . 22
9.1.4 Design value of deflection . 22
9.1.5 Comparisons of stress and deflection . 22
9.2 Calculation method for laminated glass and laminated safety glass . 23
9.2.1 Calculation method. 23
9.2.2 Simplified method . 23
9.2.3 Determination of ω . 24
9.3 Calculation method for insulating glass units . 25
Annex A (normative) Principles of determining the load resistance of glass by testing . 27
A.1 General . 27
A.2 Factors affecting load resistance . 28
A.3 Effect of rate and duration of loading . 28
A.4 Effect of stressed surface area . 29
A.5 Surface condition. 29
A.6 Temperature . 29
Annex B (informative) Calculation formulae for stress and deflection for large deflections of
rectangular panes supported on all edges . 30
Annex C (informative) Calculation process for insulating glass units . 33
C.1 Double glazed insulating glass units . 33
C.1.1 Sign convention for actions and effects . 33
C.1.2 General . 33
C.1.3 Distribution (partition) of external loads (load sharing) . 34
C.1.4 Effect of internal loads . 34
C.1.5 Calculation of double glazed insulating glass unit cavity temperature . 35
C.2 Triple glazed insulating glass units . 36
C.2.1 Sign convention for actions and effects . 36
C.2.2 Calculation process . 36
C.2.3 Calculation of triple glazed insulating glass unit cavity temperature . 39
C.3 Calculation of the insulating glass unit seal edge force . 40
Annex D (informative) Proposal for a model of a National Annex . 41
D.1 Partial material factors . 41
D.2 Partial load factors . 41
D.3 Factors for load duration, k . 42
mod
D.4 Deflection limits . 42
Bibliography . 43

Foreword
This document (prEN 16612:2013) has been prepared by Technical Committee CEN/TC 129 “Glass in
building”, the secretariat of which is held by NBN.
This document is currently submitted to the CEN Enquiry.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
Introduction
This European Standard gives the principles of determining the load resistance of glass.
The principles of determining the load resistance of glass are based on the structural Eurocode EN 1990:
Basis of structural design. The actions are determined in accordance with the structural Eurocode series
EN 1991: Basis of structural design - Actions on structures, including the National annexes.
In the design processes, the reliability is part of national competency. For that reason this European Standard
foresees that, to conform the rules applied by the Eurocodes, the material partial factors γ are subject to
M
nationally determined parameters:
– values for the ultimate limit state (ULS).
The values can be found in an informative (National) annex to this European Standard.
When a Member State does not use its prerogative and no values for the material partial factor have been
determined, the recommended values given in this European Standard should be used.
1 Scope
This European Standard gives the principles of determining the load resistance of glass. It gives
• the general method of calculation, and
• determination of load resistance by testing for any application.
This European Standard does not determine suitability for purpose. Resistance to applied loads is only one
part of the design process, which may also need to take into account
• environmental factors (e.g. sound insulation, thermal properties),
• safety characteristics (e.g. fire performance, breakage characteristics in relation to human safety, security)
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 410, Glass in building - Determination of luminous and solar characteristics of glazing
EN 572, Glass in building - Basic soda lime silicate glass products
EN 572-1, Glass in building - Basic soda lime silicate glass products - Part 1: Definitions and general physical
and mechanical properties
EN 673, Glass in building - Determination of thermal transmittance (U value) - Calculation method
EN 1036, Glass in building - Mirrors from silver coated float glass for internal use
EN 1096, Glass in building - Coated glass
EN 1279, Glass in building - Insulating glass units
EN 1748-1, Glass in building - Basic borosilicate glass products
EN 1748-1-1, Glass in building - Basic borosilicate glass products - Part 1: Definitions and general physical
and mechanical properties
EN 1748-2, Glass in building - Basic glass ceramics products
EN 1748-2-1, Glass in building - Basic glass ceramics products - Part 1: Definitions and general physical and
mechanical properties
EN 1863, Glass in building - Heat strengthened soda lime silicate glass
EN 1863-1, Glass in building - Heat strengthened soda lime silicate glass - Part 1: Definition and description
EN 1990:2002, Eurocode – Basis of structural design
EN 1991, Actions on structures
EN 1991-1-4, Wind actions
EN 1997, Geotechnical design
EN 1998, Design of structures for earthquake
EN 12150, Glass in building - Thermally toughened soda lime silicate safety glass
EN 12150-1, Glass in building - Thermally toughened soda lime silicate safety glass - Part 1: Definition and
description
EN 12337, Glass in building - Chemically strengthened soda lime silicate glass
EN 12337-1, Glass in building - Chemically strengthened soda lime silicate glass - Part 1: Definition and
description
EN ISO 12543, Glass in building - Laminated and laminated safety glass
EN ISO 12543-1, Glass in building - Laminated and laminated safety glass - Part 1: Definitions and description
of component parts
EN 13024, Glass in building - Thermally toughened borosilicate safety glass
EN 13024-1, Glass in building - Thermally toughened borosilicate safety glass - Part 1: Definition and
description
EN 13363-2:2005, Solar protection devices combined with glazing – Calculation of total solar energy
transmittance – Part 2: Detailed calculation method
EN 14178, Glass in building - Basic alkaline earth silicate glass products
EN 14178-1, Glass in building - Basic alkaline earth silicate glass products - Part 1: Definitions and general
physical and mechanical properties
EN 14179, Glass in building - Heat soaked thermally toughened soda lime silicate safety glass
EN 14179-1, Glass in building - Heat soaked thermally toughened soda lime silicate safety glass - Part 1:
Definition and description
EN 14321-1, Glass in building - Thermally toughened alkaline earth silicate safety glass
EN 14321-1, Glass in building - Thermally toughened alkaline earth silicate safety glass - Part 1: Definition
and description
EN 14449, Glass in building - Laminated glass and laminated safety glass - Evaluation of conformity/Product
Standard
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
annealed glass
glass which has been treated during manufacture to minimise the residual stress in the glass, allowing it to be
cut by scoring and snapping
EXAMPLES Examples are float glass, drawn sheet glass, patterned glass and wired glass.
3.2
effective thickness (of laminated glass)
thickness calculated for laminated glass which, when used in place of the glass thickness in an engineering
formula, will result in a reasonably accurate determination of the deflection of and / or stress in the laminated
glass
3.3
prestressed glass
glass which has been subjected to a strengthening treatment, by heat or chemicals, which induces a
compressive surface stress into the whole surface of the glass, balanced by a tensile stress within the body of
the glass
EXAMPLES Examples are thermally toughened safety glass, heat strengthened glass and chemically strengthened
glass.
3.4
enamelled glass
glass which has a glass powder emulsion applied to the surface, by e.g. painting or screen printing, which is
subsequently fired into the surface of the glass
EXAMPLE Examples are enamelled heat strengthened glass, enamelled toughened glass and enamelled heat
soaked toughened glass.
3.5
main structure
beams, columns, floor forming the main structure of the building (see Figure 1)
Note 1 to entry: The main structure is commonly class of consequence CC2 or CC3.

Key
1 main structure
2 secondary structure
3 infill panel
Figure 1 — Identification of structure
Note 2 to entry: Elements of main structure are structural in so far as they carry themselves and secondary structures,
and, in case of failure, endanger the fundamental stability of the building. The main structural elements must have a safety
and a reliability appropriate to their design use and larger factor of safety than the one applicable to the secondary
structure or to the non structural infill elements. These main structures are the reference structure and constitute the point
of reference for the coefficients determined hereafter.
3.6
secondary structure
windows assembly frames, which are secondary structures insofar as their stability is their own
EXAMPLE An example of glass secondary structure is glass fins.
Note 1 to entry: Secondary structures are commonly class of consequence CC1 or CC2.
Note 1 to entry: A failure of these secondary structures only affects the infill panels or the non-structural elements
carried by this secondary structure and in no case has any effects on the main structure of the building. The secondary
structures can be replaced independently of the main structures.
3.7
infill panels
elements placed in structures in order to close a building and which do not contribute in any manner to the
stability of the main structure
Note 1 to entry: Infill panels are commonly a class of consequence lower than CC1.
3.8
classes of consequence
classes which allow for the fact that the failure of the secondary structures or the infill panels does not have
the same economic and/or human consequences of that of the failure of the main structures
Note 1 to entry: An adapted factor of safety is thus acceptable on the actions. The coefficient of class of consequence,
k expresses the adaptation of the factor of safety applicable to the secondary structures and infill panels compared to
FI,
that applicable for the main structures according to the EN 1990, Annex B. This coefficient is integrated in the partial
coefficients relating to the actions, γ and γ except in the case where the action has a favourable effect in a combination
Q G,
of actions. The coefficient of class of consequence does not apply to the partial coefficients relating to materials.
3.9
unfactored load
action as obtained from EN 1991 (e.g. wind load, snow load), including all the factors relevant for determining
the action, but before applying the partial factors for actions γ , γ and/or ψ
Q G
4 Symbols and abbreviations
For the purposes of this document, the following symbols and abbreviations apply.
A Surface area of the pane ( = a x b)
a Shorter dimension of the pane
a*
Characteristic length of an insulating glass unit
b Longer dimension of the pane
C Limiting design value of the relevant serviceability criterion
d
c Coefficient for the effect of altitude change on isochore pressure (=0,12 kPa/m)
H
c Coefficient for the effect of cavity temperature change on isochore pressure (=0,34 kPa/K)
T
E
Young’s modulus
E Effect of the action(s)
d
E Serviceability limit state value of the effect of the action(s)
SLS;d
E Ultimate limit state value of the effect of the action(s)
ULS;d
E Ultimate limit state value of the effect of a permanent action
ULS;G
E Ultimate limit state value of the effect of a non-dominant action
ULS;i
E
Ultimate limit state value of the effect of the dominant action
ULS;1
E{F } Calculation of the effect of the serviceability limit state design value
SLS;d
E{F } Calculation of the effect of the ultimate limit state design value
ULS;d
F Design value of the action
d
F Design value of the action on pane 1 of an insulating glass unit
d;1
F Design value of the action on pane 2 of an insulating glass unit
d;2
F
Serviceability limit state design value of a single action or of a combination of actions.
SLS;d
F Ultimate limit state design value of a single action or of a combination of actions.
ULS;d
f Characteristic value of the bending strength of prestressed glass
b;k
f Design value of strength for the surface of glass panes
g;d
f Characteristic value of the bending strength of annealed glass
g;k
G Value of self weight load
G
Value of self weight load of pane 2
H Altitude
H Altitude of production of insulating glass unit
P
h Nominal thickness of the pane
h Nominal thickness of pane 1 of an insulating glass unit or ply 1 of a laminated glass
h Nominal thickness of pane 2 of an insulating glass unit or ply 2 of a laminated glass
h
Nominal thickness of pane 3 of an insulating glass unit or ply 3 of a laminated glass
h External heat transfer coefficient
e
h Effective thickness of a laminated glass for calculating out-of-plane bending deflection
ef;w
Effective thickness of a laminated glass for calculating out-of-plane bending stress of ply j
h
ef;σ;j
h Internal heat transfer coefficient
i
h Nominal thickness of pane j of an insulating glass unit or ply j of a laminated glass
j
h Nominal thickness of pane k of an insulating glass unit or ply k of a laminated glass
k
h The distance of the mid-plane of the glass ply 1 from the mid-plane of the laminated glass
m;1
h The distance of the mid-plane of the glass ply 2 from the mid-plane of the laminated glass
m;2
h The distance of the mid-plane of the glass ply 3 from the mid-plane of the laminated glass
m;3
h The distance of the mid-plane of the glass ply j from the mid-plane of the laminated glass
m;j
h The distance of the mid-plane of the glass ply k from the mid-plane of the laminated glass
m;k
h Cavity heat transfer coefficient
s
h Cavity heat transfer coefficient - cavity 1
s1
h Cavity heat transfer coefficient - cavity 2
s2
J Variable used in calculations of cavity temperatures for triple glazed insulating glass units
A
J Variable used in calculations of cavity temperatures for triple glazed insulating glass units
B
J
Variable used in calculations of cavity temperatures for triple glazed insulating glass units
C
J Variable used in calculations of cavity temperatures for triple glazed insulating glass units
D
k Coefficient used in the calculation of large deflection stresses
k Coefficient used in the calculation of large deflection deflections
k Coefficient used in the calculation of large deflection volume changes
k Coefficient of class of consequence expressing the reduction of safety applicable to the
FI
secondary structures and infill panels compared to that applicable for the main structures
k Factor for the load duration
mod
k Factor for the load duration of the dominant action in a load combination
mod;1
k Factor for the load duration when there are combined loads
mod;c
k Factor for the load duration of a permanent in a load combination
mod;G
k Factor for the load duration of a non-dominant action in a load combination
mod;i
k
Factor for the glass surface profile
sp
k Factor for strengthening of prestressed glass
v
p Pressure
p Isochore pressure for an insulating glass unit
p Air pressure
a
p
Isochore pressure due to the effect of change in cavity temperature and air pressure
C;0
p Externally applied uniformly distributed load on pane 1 of a triple insulating glass unit
ex;1
p Externally applied uniformly distributed load on pane 3 of a triple insulating glass unit
ex;3
p Isochore pressure due to the effect of change in altitude
H;0
p Air pressure at the time of production of insulating glass unit
P
p Load partition for pane 1 of a triple insulating glass unit
res;1
p
Load partition for pane 2 of a triple insulating glass unit
res;2
p Load partition for pane 3 of a triple insulating glass unit
res;3
p* Non-dimensional uniformly distributed load
Q Value of the single action or dominant action
k,1
Q Values of the actions which are not dominant
k,i
R Design value of the resistance to the actions
d
s
Nominal cavity width of a double glazed insulating glass unit
s Nominal cavity width of cavity 1 in a triple glazed insulating glass unit
s Nominal cavity width of cavity 2 in a triple glazed insulating glass unit
T Insulating glass unit cavity temperature
C
T Insulating glass unit cavity temperature - cavity 1
C1
T Insulating glass unit cavity temperature - cavity 2
C2
T
External air temperature
ext
T Glass temperature of the central pane of a triple glazed insulating glass unit
g;cen
T Glass temperature of the outer pane of an insulating glass unit
g;ext
T Glass temperature of the inner pane of an insulating glass unit
g;int
T Internal (room) air temperature
int
T Temperature of production of insulating glass unit
P
t
Load duration (in hours)
V Volume change in an insulating glass unit cavity due to the deflection of one of the panes
V Nominal volume of cavity 1 in an insulating glass unit
pr;1
V Nominal volume of cavity 2 in an insulating glass unit
pr;2
V Nominal volume of cavity k in an insulating glass unit
pr;k
w
Design value of deflection
d
w Maximum deflection calculated for the design load
max
z Coefficient used in the approximate calculation of k
1 4
z Coefficient used in the approximate calculation of k
2 1
z Coefficient used in the approximate calculation of k
3 1
z Coefficient used in the approximate calculation of k
4 1
+
Relative volume changes for the panes on either side of cavity 1 of a triple insulating glass unit
α , α
1 1
+
Relative volume changes for the panes on either side of cavity 2 of a triple insulating glass unit
α , α
2 2
+
Relative volume changes for the panes on either side of cavity i of a triple insulating glass unit
α , α
i i
Solar direct effective absorptance of the outer pane of an insulating glass unit
α
e1
α Solar direct effective absorptance of the second pane of an insulating glass unit
e2
Solar direct effective absorptance of the third pane of an insulating glass unit
α
e3
Factor used in calculating internal pressure differences in triple insulating glass units
β
Internal pressure difference for cavity 1 of a triple insulating glass unit
∆p
Internal pressure difference for cavity 2 of a triple insulating glass unit
∆p
Stiffness partition for pane 1 of a double insulating glass unit
δ
Stiffness partition for pane 2 of a double insulating glass unit
δ
φ Insulating glass unit factor for a double insulating glass unit
Insulating glass unit factor for cavity 1 of a triple insulating glass unit
φ
Insulating glass unit factor for cavity 2 of a triple insulating glass unit
φ
Incident solar radiant flux
φ
e
Partial factor for permanent actions, also accounting for model uncertainties and dimensional
γ
G
variations
γ Material partial factor
M
γ Material partial factor for annealed glass
M;A
Material partial factor for surface prestress
γ
M;v
Partial factor for variable actions, also accounting for model uncertainties and dimensional
γ
Q
variations
λ
Aspect ratio of the pane ( =a b )
Poisson number
µ
Volume change of glass pane 1 when subjected to unit uniform pressure
ν
p;1
Volume change of glass pane 2 when subjected to unit uniform pressure
ν
p;2
Volume change of glass pane 3 when subjected to unit uniform pressure
ν
p;3
Volume change of glass pane k when subjected to unit uniform pressure
ν
p;k
Glass density
ρ
σ Maximum stress calculated for the design load
max
Combination factors for the actions
ψ
Combination factors for the actions which are not dominant
ψ
0,i
Partial factor for a frequent value of a variable action
ψ
NOTE 1 This value is determined - in so far as it can be fixed on statistical bases - so that either the
total time, within the reference period, during which it is exceeded is only a small given part of the reference
period, or the frequency of it being exceeded is limited to a given value. It may be expressed as a
determined part of the characteristic value by using a factor ψ ≤ 1.
Combination factor for a quasi-permanent value of a variable action
ψ
NOTE 2 This value is determined so that the total period of time for which it will be exceeded is a large
fraction of the reference period. It may be expressed as a determined part of the characteristic value by
using a factor ψ ≤ 1.
Combination factor for a quasi-permanent value of a variable action
ψ
2,i
NOTE 3 This value is determined so that the total period of time for which it will be exceeded is a large
fraction of the reference period. It may be expressed as a determined part of the characteristic value by
using a factor ψ ≤ 1.
2;i
Coefficient for the shear transfer of an interlayer in laminated glass
ω
5 Requirements
5.1 Basis of determination of load resistance of glass
The process shall conform to EN 1990: Eurocode – Basis of structural design.
The determination of actions shall be in accordance with the relevant parts of EN 1991: Actions on structures.
Where relevant or required, the following shall also be taken into account.
• EN 1997: Geotechnical design, and
• EN 1998: Design of structures for earthquake design.
5.2 General requirements
Table 1 — Table of requirements for the various limit states
Ultimate limit state Serviceability limit state
Requirement
E ≤ R (1) E ≤C (2)
ULS;d d SLS;d d
where the effect of the actions is:
E = E{F } (3) E = E{F } (4)
ULS;d ULS;d SLS;d SLS;d
in which: F is the Ultimate Limit State F is the Serviceability Limit
ULS;d SLS;d
design value of a single action or of State design value of a single
a combination of actions. action or of a combination of
actions.
and where: E is the design value of the effect of the action(s), expressed as calculated
ULS;d
stress, caused by the action(s).
R is the design value of the corresponding resistance, expressed as
d
maximum ultimate limit state design value of strength f , taking into
g;d
account the material partial factor for the ultimate limit state γ (see 5.3).
M
E is the design value of the effect of the action(s), expressed as calculated
SLS;d
stress or deflection, caused by the action(s).
C is the limiting design value of the relevant serviceability criterion,
d
expressed as maximum serviceability limit state design value of strength
f , or limit on deflection, w , taking into account the material partial factor
g;d d
for the serviceability limit state γ (see 5.3).
M
5.3 Material partial factor
The recommended values of the material partial factor are given in Table 2.
Table 2 — Recommended values of the material partial factor
Ultimate limit state
a
Annealed glass γ = 1,8
M;A
Surface prestress
γ = 1,2
M;v
a
The material partial factor for annealed glass is also applied to a component of the
strength of prestressed glass - see Formula (9).

For specific National values, see Annex D.
5.4 Process of determining the load resistance of glass
For any calculation or test, the mechanical and physical properties of glass shall be determined in accordance
with Clause 6.
The design value of the actions shall be determined in accordance with Clause 7.
The design value of strength for the glass, for the ultimate limit state and for the serviceability limit state (if
required), shall be determined in accordance with Clause 8.
Where a design deformation limit applies for the serviceability limit state, such a value shall be determined in
accordance with EN 1990. Where no other standard specifies a design deformation limit, this shall be
determined in accordance with 9.1.4.
For calculations, the principles and conditions shall be in accordance with Clause 9.
Determination of load resistance by testing, or assisted by testing, shall be in accordance with Annex A.
6 Mechanical and physical properties of glass
6.1 Values
The values of the mechanical and physical properties needed for calculation, such as Young's modulus E, the
Poisson number µ, and the density of glass ρ, are obtained from the following product standards:
EN 572-1, EN 1748-1-1, EN 1748-2-1, EN 1863-1, EN 12150-1, EN 12337-1, EN ISO 12543-1, EN 13024-1,
EN 14178-1, EN 14179-1, EN 14321-1.
6.2 Approximate values
When (e.g. for assembling different glass materials) no distinction between the various differences in
mechanical and physical properties can be taken into account, or when it is not necessary, the following
values (for soda-lime-silicate glass) may be used for all glass types:
glass density  ρ = 2 500 kg/m³;
Young’s modulus  E = 70 000 MPa;
Poisson number µ = 0,22;
7 Actions
7.1 Assumptions related to the actions and combinations of actions
With regard to actions and combinations of actions in the service limit state, the frequent combination applies.
(see EN 1990:2002 clauses 6.5.3 and 4.1.3)
With regard to the combination of the actions in an ultimate limit state, the fundamental combination applies.
(See EN 1990:2002 clauses 6.4.3 and 4.1.3)
7.2 Combinations of actions
The values of the actions shall be determined in accordance with the appropriate parts of EN 1991.
The design value of the action (design load) shall be:
for ultimate limit state
F = γ .G"+"γ .Q "+"γ ψ Q (5)
d G Q k ,1 Q∑ 0,i k ,i
i
for serviceability limit state
F =G"+"ψ .Q "+" ψ Q (6)
d 1 k ,1 ∑ 2,i k ,i
i
where
F is the design value of the combination of actions;
d
G is the value of permanent actions (e.g. self-weight load, permanent equipment);
Q is the characteristic value of the leading variable action (e.g. imposed load on floor, wind, snow),
k,1
Q is the characteristic value of the accompanying variable action (e.g. wind, snow)
k,i
ψ are factors for combination value of accompanying variable actions
0,i
ψ is the factor for frequent value of a variable action
ψ :is the factor for quasi-permanent value of a variable action
2,i
γ is the partial factor for permanent actions, also accounting for model uncertainties and dimensional
G
variations
γ : is the partial factor for variable actions, also accounting for model uncertainties and dimensional
Q
variations
The recommended values of the partial load factors, γ, are given in Table 3.
Table 3 — Partial load factors
c
Type of element to be γ
G
γ
calculated Q
favourable unfavourable
a
Main structure see see see
Eurocodes Eurocodes Eurocodes
a
Secondary structure see see see
Eurocodes Eurocodes Eurocodes
a
Infill panel (class of see see see
consequence CC1) Eurocodes Eurocodes Eurocodes
b
Infill panel (class of
consequence lower than 1,1 1,0 1,1
CC1)
a
Structural construction covered by Eurocodes
b
Non structural element not covered by Eurocodes
c
The lower value is used when the permanent action has a favourable effect in
combination with other actions. The higher value is used when the permanent
action is considered acting alone or has a unfavourable effect in combination
with other loads.
For specific National values, see Annex D.
The recommended values of the partial factors, ψ, are given in Table 4.
Table 4 — ψ factors
a a a b
Main structure Secondary structure Infill panel Infill panel
Wind see Eurocodes see Eurocodes see Eurocodes 0,6
ψ
ψ see Eurocodes see Eurocodes see Eurocodes 0,9
0,2
ψ see Eurocodes see Eurocodes see Eurocodes
Snow 0,6
ψ see Eurocodes see Eurocodes see Eurocodes
see Eurocodes see Eurocodes see Eurocodes 1,0
ψ
ψ see Eurocodes see Eurocodes see Eurocodes 0,2
Other
ψ See Eurocodes or national annexes
See Eurocodes or national annexes
ψ
See Eurocodes or national annexes
ψ
a
Structural construction covered by Eurocodes
b
Non structural element not covered by Eurocodes

For specific National values, see Annex D.
8 Strength and stress
8.1 Design value of strength for annealed glass
8.1.1 Formulae
The design value of strength for annealed glass material, whichever composition, is
k k f
mod sp g;k
f = (7)
g;d
γ
M ;A
where
f is the characteristic value of the bending strength (f = 45 N/mm ).
g;k g;k
γ is the material partial factor for annealed glass (see 5.3 and Annex D).
M;A
k is the factor for the glass surface profile (see 8.1.2).
sp
k is the factor for the load duration(see 8.1.3).
mod
NOTE CEN report CR rrr [1] explains the origin of the value of f .
g;k
8.1.2 Glass surface profile factor
The factor for the glass surface profile is given in Table 5.
Table 5 — Factor for the glass surface profile
Glass material Factor for the glass surface profile k
sp
b b
(whichever glass composition) As produced Sandblasted
Float glass 1,0 0,6
Drawn sheet glass 1,0 0,6
a
Enamelled float or drawn sheet glass (1,0) (0,6)
Patterned glass 0,75 0,45
a
Enamelled patterned glass (0,75) (0,45)
Polished wired glass 0,75 0,45
Patterned wired glass 0,6 0,36
a
These glass types are not generally available as annealed glass, but the values of k are also required in the
sp
formulae for prestressed glass (see 8.2).
b
For acid etched glass, the ‘as produced’ value of k should be used
sp
8.1.3 Factor for duration of load
The factor for the load duration of annealed glass is
−
k = 0,663t (8)
mod
where
t is the load duration in hours.
For normal building loads, the factor k has a maximum value of k = 1 and a minimum value of
mod mod
k = 0,25.
mod
NOTE For exceptional loads of very short duration, e.g. explosions, values of k greater than 1 may be used. The
mod
formula in Formula (8) may be considered valid for durations down to 20 ms.
Typical values of k are given in Table 6.
mod
Table 6 — Factors for load duration
Action Load duration k
mod
a
personnel loads short, single 0,89
b
wind single gust 1,0
b
wind short, multiple 0,74
c
snow intermediate 0,44
daily temperature variation intermediate 0,57
11 hours extreme peak duration
barometric pressure variation intermediate 0,50
yearly temperature variation intermediate 0,39
6 month extreme mean value duration
dead load, self weight permanent 0,29
a
The value of k =0,89 is based on a personnel load of 30 seconds duration. Other values may be considered
mod
depending on the type of personnel load being evaluated and also the building use.
b
The value of k =0,74 is based on a cumulative equivalent duration of 10 minutes, considered representative of the
mod
effect of a storm which may last several hours. Higher values of k may be considered for wind.
mod
c
k =0,44 can be considered representative for snow loads lasting between 1 week (k =0,48) and 3 months
mod mod
(k =0,41). Other values of k may be appropriate depending on local climate.
mod mod
Where loads with different durations need to be treated in combination, the k for the load combination is the
mod
highest value from Table 6 which is associated with any of the loads in the combination.
NOTE For example, if glass is subject to wind, snow and self weight loads, the effects of a combination of snow and
self weight would be evaluated using a k of 0.44 and the effects of a combination of wind, snow and self weight loads
mod
would be evaluated using a k of 0.74 (or 1.0). All possible combinations should be checked.
mod
For specific National values of k and the National method of treating combined loads, see Annex D.
mod
8.2 Design value of strength for prestressed glass
8.2.1 Formula
The design value of strength for prestressed glass material, whichever composition, is
k k f k (f − f )
mod sp g;k v b;k g;k
f = + (9)
g;d
γ γ
M ;A M ;v
where
f , γ , k and k are described in 8.1.
g;k M;A mod sp
γ is the material partial factor for surface prestress (see 5.3
...