prEN 16613

SLOVENSKI STANDARD
01-september-2013
Steklo v gradbeništvu - Lepljeno steklo in lepljeno varnostno steklo - Ugotavljanje
mehanskih lastnosti vmesnih slojev
Glass in building - Laminated glass and laminated safety glass - Determination of
interlayer mechanical properties
Glas im Bauwesen - Verbundglas und Verbundsicherheitsglas - Bestimmung der
mechanischen Eigenschaften von Zwischenschichten
Ta slovenski standard je istoveten z: prEN 16613
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 - Laminated glass and laminated safety glass -
Determination of interlayer mechanical properties
Glas im Bauwesen - Verbundglas und
Verbundsicherheitsglas - Bestimmung der mechanischen
Eigenschaften von Zwischenschichten
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 16613:2013: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Symbols and abbreviations .6
5 Selection of testing procedure .7
5.1 Isotropic interlayer materials .7
5.2 Non-isotropic interlayer materials .7
5.3 Interlayers which cannot be formed into small test pieces .8
6 Test procedure .8
6.1 General .8
6.2 Test specimens .8
6.3 Test method .9
6.3.1 Glass transition temperature, T .9
g
6.3.2 Determination of E (θ ,f) .9
L
6.4 Determination of E (T ,f) . 10
L ref
7 Evaluation of ω . 10
7.1 Determining E (θ,f) . 10
L
7.2 Load durations and temperature ranges . 11
7.3 Determining the interlayer stiffness family . 11
8 Test report . 13
Annex A (normative) Alternative method for interlayers which cannot be formed into small test
pieces . 15
A.1 Method . 15
A.2 Sample . 15
A.3 Test conditions . 16
A.4 Interpretation of the results . 16
A.5 Extrapolation to long duration curves . 16
A.6 Interlayer shear coefficient, ω, and load case . 16
Annex B (informative) Preparation of test specimens . 17
B.1 Folio interlayers . 17
B.1.1 Polyvinyl butyral (pvb), eva, and polyurethane (pu) . 17
B.1.2 Ionoplast interlayers . 17
B.2 Cast in place interlayers . 17
B.3 Intumescent interlayers . 17
Annex C (informative) Interlayer stiffness family . 18
Annex D (informative) Determination of the interlayer shear transfer coefficient from the interlayer
modulus . 19
D.1 Summary of the evaluation . 19
D.2 Evaluation of ω(θ,t) . 19
D.2.1 Finite element calculation taking into account the interlayer properties . 19
D.2.2 Upper and lower bounds . 20
D.2.3 Determination of equivalent thickness . 20
D.2.4 Determination of ω from h . 21
mono
Bibliography . 22

Foreword
This document (prEN 16613:2013) 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
The purpose of this European Standard is to provide the viscoelastic properties of interlayer materials in order
that calculations for the load resistance of laminated glass panes can be undertaken.
In addition, this European Standard includes a procedure for categorising the interlayer materials into a
families, which can be associated with shear transfer coefficients which are used in a simplified calculation
method.
NOTE CEN/TC 129/WG 8 "Mechanical strength" is preparing a draft which includes the simplified calculation
method [1].
1 Scope
This European Standard specifies a test method for determining the mechanical viscoelastic properties of
interlayer materials. The interlayers under examination are those used in the production of laminated glass
and/or laminated safety glass. The interlayer properties are needed in order to determine the load resistance
of laminated glass as part of a general calculation method for the load resistance of glass.
NOTE CEN/TC 129/WG 8 "Mechanical strength" is preparing a draft for the calculation method [1].
From the tensile modulus in particular conditions of temperature and load duration, an interlayer can be
placed into a family that relates to a specific interlayer shear transfer coefficient, ω. This value can be used in
a simplified calculation method.
An informative annex explains the background to the determination of families relating to a specific interlayer
shear transfer coefficient.
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 1288-3, Glass in building - Determination of the bending strength of glass - Part 3: Test with specimen
supported at two points (four point bending)
ISO 6721-1, Plastics – Determination of mechanical dynamic properties – Part 1: General principles
ISO 6721-4, Plastics – Determination of mechanical dynamic properties – Part 4: Tensile vibration – Non-
resonance method
ISO 6721-11, Plastics – Determination of mechanical dynamic properties – Part 11: Glass transition
temperature
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
glass transition temperature
interval of temperature in which a material changes from a rubbery state to a solid state
3.2
interlayer shear transfer coefficient
coefficient between 0 and 1 describing the ability of an interlayer material to transfer shear forces between the
glass plies of a laminated glass plate when submitted to bending
3.3
stiffness family
group of interlayers having similar properties for the temperature range and load durations considered
3.4
vitreous polymer
polymer presenting a glass transition temperature in the range of building applications
4 Symbols and abbreviations
For the purposes of this document, the following symbols and abbreviations apply.
b Width of the test specimen
C , C Parameters in the WLF visco-elastic formula
1 2
e Thickness of the test specimen
E
Young’s Modulus of glass
G
E Young’s Modulus of the interlayer material
L
f Frequency
F Four point bend test load
G Shear modulus of the interlayer material
L
h Nominal thickness of ply k of a laminated glass
k
h The distance of the mid-plane of the glass ply k from the mid-plane of the laminated glass
m;k
h Equivalent thickness of monolithic glass for a laminated glass deflecting under load
mono
H Height of the test specimen
L : Distance between centre lines of the supporting rollers
S
L : Distance between centre lines of the bending rollers
B
Q: Self-weight area density of four point bend test specimen
t
Load duration
T Temperature
T Glass transition temperature
g
T Reference temperature
ref
w: Measured deflection of four point bend test specimen
Temperature transformation parameter in the WLF visco-elastic formula
α(Τ)
Temperature
θ
Poisson’s number of the interlayer material
µ
Interlayer shear transfer coefficient
ω
5 Selection of testing procedure
5.1 Isotropic interlayer materials
The commonly used interlayers are generally isotropic materials. The most practical method for testing
isotropic interlayer materials consists is to undertake a tensile test which can be used to determine the shear
modulus using to the following relationship:
E
L
G = (1)
L
2(1+ µ)
where
μ is the Poisson’s number of the interlayer (μ equals 0,49 for an isotropic interlayer).
This leads to the approximation.
E ≈ 3G (2)
L L
A typical test piece is shown in Figure 1.

Figure 1 — Dimensions of the isotropic interlayer test piece used for tensile test
Typical dimensions of the test piece are:
 H = 10 mm
 b = 5 mm
 e ~ 2,3 mm (equivalent to stacking 6 plies of interlayer each with nominal thickness of 0,38 mm).
5.2 Non-isotropic interlayer materials
In the case of interlayers which are not isotropic materials (an example is the acoustic tri-layer pvb), it is
necessary to assess the shear stress directly by using a dynamic shear test method. The principle of the test
piece is presented in Figure 2.
Key
1 glass
2 interlayer
Figure 2 — Principle of a test specimen for dynamic shear test of an anisotropic interlayer
Typical dimensions of the test piece are:
 H = 10 mm
 b = 5 mm
 e ~ 2.3 mm (equivalent to stacking 6 plies of interlayer each with nominal thickness of 0.38 mm).
Critical dimensions of the sample are H > 4 e and 10 mm < H < 15 mm.
5.3 Interlayers which cannot be formed into small test pieces
There are some interlayers which cannot be formed into test pieces like those described in 5.1 and 5.2 or
which are not stable with exposed edges in such small sizes.
For these interlayer materials, the relevant interlayer properties can be determined by calculation from the
results of bending tests. A method for doing this is given in Annex A.
6 Test procedure
6.1 General
The method uses the tests described in ISO 6721-1, 6721-4, and 6721-11. ISO 6721-1 gives an overview of
the principles of these tests.
6.2 Test specimens
The test specimens shall be manufactured from samples representative of normal interlayer material
production. The test specimens shall be processed under normal laminating conditions (see Annex B).
The thickness, e, of the test specimens should be not less than 2.2 mm thick and not more than 4.0 mm thick.
The layering and stacking of the interlayer material to achieve an appropriate thickness shall be representative
of normal production processes.
The test specimen size and tolerances on dimensions shall be determined according to the requirements of
ISO 6721-4.
Two sets of test specimens are required. One set is used for determining the glass transition temperature, T ,
g
(see 6.3.1). The other set is used for the evaluation of the E (T ,f) curv
...