prEN 1748-2-1

SLOVENSKI STANDARD
01-oktober-2017
Steklo v stavbah - Posebni osnovni proizvodi - Steklena keramika - 2-1. del:
Definicije in splošne fizikalne in mehanske lastnosti
Glass in Building - Special basic products - Glass ceramics - Part 2-1: Definitions and
general physical and mechanical properties
Glas im Bauwesen - Spezielle Basiserzeugnisse - Glaskeramik - Teil 2-1: Definitionen
und allgemeine physikalische und mechanische Eigenschaften
Verre dans la construction - Produits de base spéciaux - Vitrocéramiques - Partie 1 :
Définitions et propriétés physiques et mécaniques générales
Ta slovenski standard je istoveten z: prEN 1748-2-1
ICS:
01.040.81 6WHNODUVNDLQNHUDPLþQD Glass and ceramics
LQGXVWULMD6ORYDUML industries (Vocabularies)
81.040.20 Steklo v gradbeništvu Glass in building
81.060.01 Keramika na splošno Ceramics in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2017
ICS 01.040.81; 81.040.20; 81.060.01 Will supersede EN 1748-2-1:2004
English Version
Glass in Building - Special basic products - Glass ceramics -
Part 2-1: Definitions and general physical and mechanical
properties
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, Serbia, 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

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1748-2-1:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Chemical composition . 6
4.1 General . 6
4.2 Tint . 7
5 Physical and mechanical characteristics . 7
5.1 General characteristics . 7
5.2 Characteristic bending strength . 8
5.3 Designation of clear glass ceramics . 8
5.3.1 General . 8
5.3.2 Clear transparent glass ceramics . 9
5.3.3 Clear translucent glass ceramics . 9
5.4 Stability of physical and chemical characteristics . 10
6 Dimensional requirements. 10
6.1 Manufacturing dimensions . 10
6.1.1 Stock sizes . 10
6.1.2 Supplied and final cut sizes . 10
6.2 Thickness and thickness tolerances . 10
6.3 Length, width and squareness . 11
7 Quality requirements . 11
7.1 General . 11
7.2 Quality criteria and their evaluation . 12
7.2.1 Optical . 12
7.2.2 Appearance . 12
7.3 Methods of observation and measurement . 12
7.3.1 Optical faults . 12
7.3.2 Visual faults (spot faults, linear/extended faults), all types of glass ceramics . 13
7.4 Acceptance levels . 14
7.4.1 Optical faults . 14
7.4.2 Visual faults (spot faults, linear/extended faults, all types of glass ceramics) . 14
7.5 Edge defects for final cut sizes . 15
7.5.1 Entrant and emergent faults . 15
7.5.2 Bevel . 16
7.5.3 Limitations on edge defects . 16
8 Designation. 16
Annex A (informative) Complementary information related to REACH . 18
Bibliography . 19

European foreword
This document (prEN 1748-2-1:2017) 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 will supersede EN 1748-2-1:2004.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
The main changes compared to the previous edition are the following:
a) Clause 1: drawn and casted process have been removed;
b) Chemical composition has been modified in Table 1 to express composition in elements;
c) Clause 5: luminous transmittance have been modified;
d) Clause 6: new thickness tolerances have been added for floated glass ceramics and sub Clause 6.3
“Tolerances and squareness” has been completely revised; the squareness of rectangular glass
panes is now expressed by the difference between its diagonals;
e) Clause 7 has been completely revised (including the Zebra method of observation optical faults);
f) Categories of defects have been removed, only one quality is defined (Table 9);
g) a new informative Annex A given complementary information related to REACH has been added;
h) the document has been editorial revised.
EN 1748 is currently composed with the following parts:
— EN 1748-1-1, Glass in building — Special basic products —Borosilicate glasses — Part 1-1: Definition
and general physical and mechanical properties;
— EN 1748-1-2, Glass in building — Special basic products — Borosilicate glasses — Part 1-2:
Evaluation of conformity/Product standard;
— EN 1748-2-1, Glass in Building — Special basic products — Glass ceramics — Part 2-1: Definitions
and general physical and mechanical properties;
— EN 1748-2-2, Glass in building — Special basic products — Glass ceramics — Part 2-2: Product
standard.
1 Scope
This European Standard specifies and classifies special basic products - glass ceramics, indicates their
chemical composition, their main physical and mechanical characteristics, their dimensional and
minimum quality requirements (in respect of optical and visual faults).
This European Standard applies to special basic products - glass ceramics supplied in stock sizes,
supplied sizes or in cut sizes for final end use.
This European Standard does not apply to final cut sizes having a dimension less than 100 mm or a
surface area less than 0,05 m .
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 410:2011, Glass in building — Determination of luminous and solar characteristics of glazing
ISO 9385:1990, Glass and glass-ceramics — Knoop hardness test
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
glass ceramics
type of glass consisting of a crystalline and a residual glass phase
Note 1 to entry: The glass is obtained by normal glass manufacturing methods, e.g. floating or rolling and is
subsequently subjected to a heat treatment which transforms, in a controlled manner, part of the glass into a fine
grained crystalline phase; the glass ceramics has properties which deviate from those of the glass from which it
was transformed.
3.2
floated glass ceramics
flat, transparent or translucent, clear or tinted glass ceramics having parallel and polished faces
obtained by continuous casting and flotation on a metal bath
Note 1 to entry: In French called 'glace' and in German 'Floatglas'.
3.3
rolled glass ceramics
flat, transparent or translucent, clear or tinted glass ceramics obtained by continuous casting and
rolling
3.4
length, H and width, B
defined with reference to the direction of draw of the glass ribbon as shown in Figure 1
Key
1 → - direction of draw
H - length
B - width
Figure 1 — Relationship between length, width and direction of draw
3.5
stock sizes
glass ceramics delivered in manufacturer's standard stock sizes
3.6
supplied size
pane of glass ceramics that has been supplied either as raw material for further processing and/or
cutting down to a size for installation
Note 1 to entry: This is a size outside the stock size.
3.7
final cut size
pane of glass ceramics that has been cut down to the dimensions being required either for installation
or processing into a final product
Note 1 to entry: Examples of processed final products are insulating glass units or laminated glass of those
dimensions.
3.8
optical fault
fault which lead to distortions on the appearance of objects observed through the glass ceramics
3.9
visual fault
fault which alter the visual quality of the glass ceramics
Note 1 to entry: Visual faults include spot faults and linear / extended faults.
...