ISO 22509:2020

Glass in building — Heat strengthened soda lime silicate glass

This document specifies product definitions, product characteristics (i.e. tolerances, flatness, edgework), fracture characteristics, including fragmentation, and the physical and mechanical characteristics of flat heat strengthened soda lime silicate glass for use in buildings. This document does not cover surface finished glasses (e.g. sandblasted, acid etched) after heat strengthening. This document does not cover curved (bent) glass. Other requirements, not specified in this document, can apply to heat strengthened soda lime silicate glass which is incorporated into assemblies (e.g. laminated glass or insulating glass units), or undergoes an additional treatment (e.g. coating). The additional requirements are specified in the appropriate glass product standard. Heat strengthened soda lime silicate glass, in this case, does not lose its mechanical or thermal characteristics.

Verre dans la construction — Verre de silicate sodo-calcique durci thermiquement

General Information

• Status: Published
• Publication Date: 31-Aug-2020
• ICS: 81.040.20 - Glass in building
• Technical Committee: ISO/TC 160/SC 1 - Product considerations
• Drafting Committee: ISO/TC 160/SC 1/WG 2 - Toughened glass
• Current Stage: 6060 - International Standard published
• Start Date: 01-Sep-2020
• Due Date: 15-Jun-2020
• Completion Date: 01-Sep-2020

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22509
First edition
2020-09
Glass in building — Heat strengthened
soda lime silicate glass
Verre dans la construction — Verre de silicate sodo-calcique durci
thermiquement
Reference number
ISO 22509:2020(E)
©
ISO 2020

---------------------- Page: 1 ----------------------
ISO 22509:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

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ISO 22509:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Glass products . 2
5 Fracture characteristics . 3
5.1 General . 3
5.2 Fragmentation . 3
6 Dimensions and tolerances . 3
6.1 Nominal thickness and thickness tolerances . 3
6.2 Width and length (sizes) . 4
6.2.1 General. 4
6.2.2 Maximum and minimum sizes . 4
6.2.3 Tolerances and squareness . 4
6.2.4 Edge deformation produced by vertical heat strengthening . 5
6.3 Flatness . 5
6.3.1 General. 5
6.3.2 Measurement of overall bow . 7
6.3.3 Measurement of wave or roller wave distortion . 8
6.3.4 Measurement of edge lift (for horizontally heat strengthened glass only) . 9
6.3.5 Measurement of perimeter deformation of glass produced by air cushion
toughening process . .10
6.3.6 Measurement of local distortion (for vertically heat strengthened glass only) .10
6.3.7 Limitation on overall bow, roller wave and edge lift for horizontally heat
strengthened glass .11
6.3.8 Limitation on overall bow, wave and perimeter deformation for heat
strengthened glass manufactured by air cushion process .12
6.3.9 Limitation on overall bow and local distortion for vertically heat
strengthened glass .12
6.3.10 Other distortions .13
7 Edge work, holes, notches and cut-outs.13
7.1 General .13
7.2 Edge working of glass for heat strengthening .13
7.3 Profiled edges.14
7.4 Round holes .14
7.4.1 General.14
7.4.2 Diameter of holes .14
7.4.3 Limitations on position of holes .14
7.4.4 Tolerances on hole diameters .16
7.4.5 Tolerances on position of holes .16
7.5 Notches and cut-outs .17
7.6 Shaped panes .18
8 Fragmentation test .18
8.1 General .18
8.2 Dimensions and number of test specimens .18
8.3 Test procedure .18
8.4 Assessment of fr agmentation .19
8.5 E valuation of fragmentation .21
8.6 Test report .21
9 Other physical characteristics .21
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ISO 22509:2020(E)

9.1 Optical distortion .21
9.1.1 Heat strengthened glass produced by vertical heat strengthening .21
9.1.2 Heat strengthened glass produced by horizontal heat strengthening .21
9.1.3 Heat strengthened glass produced by the air cushion process .22
9.2 Anisotropy (iridescence) .22
9.3 Thermal durability .22
9.4 Mechanical strength .22
9.5 Surface pre-stress .23
10 Marking .23
11 Packaging .23
Annex A (informative) Alternative method for the measurement of roller wave distortion .24
Annex B (informative) Method for the measurement of the surface pre-stress of heat
strengthened glass .26
Bibliography .28
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ISO 22509:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 160, Glass in building, Subcommittee SC 1,
Product considerations.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v

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ISO 22509:2020(E)

Introduction
Heat strengthened soda lime silicate glass has a higher resistance to thermal stress and an enhanced
mechanical strength when compared to annealed soda lime silicate glass.
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INTERNATIONAL STANDARD ISO 22509:2020(E)
Glass in building — Heat strengthened soda lime silicate
glass
1 Scope
This document specifies product definitions, product characteristics (i.e. tolerances, flatness,
edgework), fracture characteristics, including fragmentation, and the physical and mechanical
characteristics of flat heat strengthened soda lime silicate glass for use in buildings.
This document does not cover surface finished glasses (e.g. sandblasted, acid etched) after heat
strengthening.
This document does not cover curved (bent) glass.
Other requirements, not specified in this document, can apply to heat strengthened soda lime silicate
glass which is incorporated into assemblies (e.g. laminated glass or insulating glass units), or undergoes
an additional treatment (e.g. coating). The additional requirements are specified in the appropriate
glass product standard. Heat strengthened soda lime silicate glass, in this case, does not lose its
mechanical or thermal characteristics.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 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 11479-1, Glass in building — Coated glass — Part 1: Physical defects
ISO 16293-1, Glass in building — Basic soda lime silicate glass products — Part 1: Definitions and general
physical and mechanical properties
ISO 16293-2, Glass in building — Basic soda lime silicate glass products — Part 2: Float glass
ISO 16293-5, Glass in building — Basic soda lime silicate glass products — Part 5: Patterned glass
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:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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ISO 22509:2020(E)

3.1
heat strengthened soda lime silicate glass
heat strengthened glass
glass within which a permanent surface compressive stress, additionally to the basic mechanical
strength, has been induced by a controlled heating and cooling process in order to give it increased
resistance to mechanical and thermal stress and prescribed fragmentation characteristics
Note 1 to entry: Thermal durability and mechanical strength are generated by the level of surface compression.
These properties are not size dependent.
3.2
air cushion process
process in which the glass is supported by an air cushion with or without additional rollers
Note 1 to entry: In this process, the glass is between horizontal and 45° of horizontal.
3.3
edge deformation
deformation of the edge caused by the tong marks
3.4
edge lift
edge dip
distortion produced in horizontally heat strengthened glass (3.1), at the leading and trailing edge of the
plate, as a result of the glass not being supported by a roller during the heat strengthening process
Note 1 to entry: This is a distortion produced by a deviation from surface flatness.
3.5
perimeter deformation
distortion around the edge of heat strengthened glass (3.1) manufactured by air cushion process (3.2)
3.6
local distortion
local deformation of vertically heat strengthened glass (3.1) underneath the tong marks
3.7
overall bow
deformation of the whole pane of heat strengthened glass (3.1) caused by the heating and cooling process
3.8
roller wave distortion
periodic deformation produced in horizontally heat strengthened glass (3.1) as a result of the glass
during heat strengthening process being in contact with the rollers
Note 1 to entry: This is a surface distortion produced by a deviation in surface flatness.
3.9
wave distortion
distortion in heat strengthened glass (3.1) manufactured by the air cushion process (3.2) as a result of
the heat strengthening process
4 Glass products
Heat strengthened glass shall be made from a monolithic glass corresponding to ISO 16293-1:
— when float glass is used it shall be in accordance to ISO 16293-2;
— when patterned glass is used it shall be according to ISO 16293-5;
— when coated glass is used it shall be according to ISO 11479-1.
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ISO 22509:2020(E)

NOTE There is no international standard for drawn sheet glass. Therefore, see EN 572-4 or national
standards.
Glass nominal thicknesses other than those covered in the above international standards are possible.
5 Fracture characteristics
5.1 General
In the event of breakage, heat strengthened glass fractures in a manner similar to annealed glass (see
Clause 8).
Fragmentation in service may not correspond exactly to that described in Clause 8, due to restraint
from fixing and external actions or due to the cause of fracture.
There can be different fragmentations if heat strengthened glass is used in laminated glass.
NOTE The fracture characteristics of glass are unaffected by temperatures between –50 °C and +100 °C.
5.2 Fragmentation
This test method is employed to demonstrate that heat strengthened glass breaks in the manner
expected for this product. The fragmentation test (see Clause 8) details the fracture pattern, especially
the maximum surface area of “islands”.
This fragmentation behaviour ignores any influence of support conditions and is a representation of
the effect of the surface pre-stress.
6 Dimensions and tolerances
6.1 Nominal thickness and thickness tolerances
The nominal thicknesses and thickness tolerances are those given in the relevant product standards
(see Clause 4), some of which are reproduced in Table 1.
Table 1 — Nominal thicknesses and tolerances
Nominal thickness Float glass tolerances Patterned glass tolerances
mm mm mm
3 ±0,3 ±0,5
4 ±0,3 ±0,5
5 ±0,3 ±0,5
6 ±0,3 ±0,5
8 ±0,6 ±0,8
10 ±0,6 ±1,0
a
12 ±0,8 ±1,5
a
This thickness is only produced by some manufacturers. Therefore, consult the manufacturer for availability.
The thickness of a pane shall be determined as for the basic product. The measurement shall be taken
at the centres of the four sides, and away from the area of any tong marks (see Figure 2), which may be
present.
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ISO 22509:2020(E)

6.2 Width and length (sizes)
6.2.1 General
When heat strengthened glass dimensions are quoted for rectangular panes, the first dimension shall
be the width, B, and the second dimension the length, H, as shown in Figure 1. It shall be made clear
which dimension is the width, B, and which is the length, H, when related to its installed position. For
heat strengthened glass manufactured from patterned glass, the direction of the pattern should be
specified relative to one of the dimensions.
Figure 1 — Examples of width, B, and length, H, relative to the pane shape
6.2.2 Maximum and minimum sizes
For maximum and minimum sizes, the manufacturer should be consulted.
6.2.3 Tolerances and squareness
The nominal dimensions for width and length being given, the finished pane shall not be larger than the
nominal dimensions increased by the tolerance, t, or smaller than the nominal dimensions reduced by
the tolerance, t. Limits are given in Table 2.
The squareness of rectangular glass panes is expressed by the difference between its diagonals. The
difference between the two diagonal lengths of the pane of glass shall not be larger than the deviation
limit, v, as specified in Table 3.
Table 2 — Tolerances, t, on width, B, and length, H
Dimensions in millimetres
Tolerance, t
Nominal dimension of side, B or H
Nominal glass thickness, d ≤ 8 Nominal glass thickness, d > 8
≤1 000 ±2 ±3
1 000 < B or H ≤ 2 000 ±3 ±3
2 000 < B or H ≤ 3 000 ±4 ±4
>3 000 ±4 ±5
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ISO 22509:2020(E)


Table 3 — Limit deviations, v, for the difference between diagonals
Dimensions in millimetres
Limit deviation, v, on the difference between diagonals
Nominal dimension, B or H
Nominal glass thickness, d ≤ 8 Nominal glass thickness, d > 8
≤ 1 000 4 6
1 000 < B or H ≤ 2 000 6 6
2 000 < B or H ≤ 3 000 8 8
> 3 000 8 10
6.2.4 Edge deformation produced by vertical heat strengthening
The tongs used to suspend the glass during heat strengthening result in surface depressions, known
as tong marks (see Figure 2). The centres of the tong marks are situated up to a maximum of 20 mm in
from the edge. A deformation of the edge less than 2 mm can be produced in the region of the tong mark
and there may also be an area of optical distortion.
Key
1 tong mark
a
Deformation in the tolerances of Table 2.
b
Up to 20 mm.
c
100 mm radius maximum area of optical distortion.
Figure 2 — Tong mark deformation
6.3 Flatness
6.3.1 General
By the very nature of the heat strengthening process, it is not possible to obtain a product as flat as
annealed glass. This difference in flatness depends on the type of glass (e.g. coated, patterned), glass
dimensions, i.e. the nominal thickness, the dimensions, the ratio between the dimensions and the type
of heat strengthening process employed.
There are six kinds of distortion:
a) overall bow (see Figure 3);
b) roller wave distortion (for horizontally heat strengthened glass only) (see Figure 4);
c) edge lift (for horizontally heat strengthened glass only) (see Figure 5);
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ISO 22509:2020(E)

d) local distortion (for vertically heat strengthened glass only) (see Figure 6);
e) wave distortion (for air cushion heat strengthened glass only) (see Figure 4);
f) perimeter deformation (for air cushion heat strengthened glass only) (see Figure 10).
NOTE Overall bow, roller wave, edge lift and perimeter deformation can, in general, be accommodated by
the framing system.
Local distortion needs to be allowed for within the glazing materials and the weather seals. For special
requirements, the manufacturers should be consulted.
Key
1 heat strengthened glass
a
Deformation for calculating overall bow.
b
B, or H, or diagonal length.
Figure 3 — Representation of overall bow
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ISO 22509:2020(E)


a
Roller wave distortion.
Figure 4 — Representation of wave or roller wave distortion
Key
1 straight edge
2 heat strengthened glass
a
Edge lift.
Figure 5 — Representation of edge lift
Key
1 heat strengthened glass
a
Local distortion.
Figure 6 — Representation of local distortion
6.3.2 Measurement of overall bow
The pane of glass shall be placed in a vertical position and supported on its longer side by two load
bearing blocks at the quarter points (see Figure 7).
For glass thinner than 4 mm nominal thickness, a solid back support with an angle between 3° and 7°
from the vertical can be used.
The deformation shall be measured along the edges of the glass and along the diagonals, as the
maximum distance between a straight metal ruler, or a stretched wire, and the concave surface of the
glass (see Figure 3).
The value for the bow is then expressed as the deformation, in millimetres, divided by the measured
length of the edge of the glass, or diagonal, in millimetres, as appropriate.
The measurement shall be carried out at room temperature.
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ISO 22509:2020(E)

Key
1 heat strengthened glass
2 load bearing blocks
a
B or H.
b
(B or H)/2.
c
(B or H)/4.
Figure 7 — Support conditions for the measurement of overall bow
Special care shall be taken for large and thin panes because they may show a buckling which is different
from an overall bow caused by the heat strengthening process. Results from this test method for glasses
thinner than 4mm may be inaccurate.
6.3.3 Measurement of wave or roller wave distortion
6.3.3.1 General
The wave or roller wave distortion is measured by means of a straight edge, or equivalent, being placed
at right angles to the wave or roller wave and bridging from peak to peak of the wave (see Figure 8).
NOTE This section deals with measurement using a straight edge and feeler gauges. An alternative method
is described in Annex A.
6.3.3.2 Apparatus
6.3.3.2.1 A straight edge, with a length between 300 mm and 400 mm.
NOTE The actual length of straight edge required depends on the wavelength of the wave or roller wave.
6.3.3.2.2 Feeler gauges, with various thicknesses in units of 0,05 mm.
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ISO 22509:2020(E)

6.3.3.3 Method
Place the straight edge so that it bridges across adjacent peaks. Insert the feeler gauge between the
glass surface and the straight edge. Increase the thickness of the feeler gauges until they just fill the gap
between glass surface and the straight edge. Record the thickness of feeler gauge(s) to an accuracy of
0,05 mm.
Repeat the measurement at several places over the glass surface.
The measured wave or roller wave distortion is the maximum value measured. The maximum allowable
values are given in Table 4 and Table 6.
6.3.3.4 Limitations
The following limitations apply:
— the wave or roller wave can only be measured on panes with a dimension greater than 600 mm
measured at right angles to the waves or roller waves;
— the wave or roller wave cannot be measured in an exclusion area that is 150 mm from the edges of
the pane. The apparatus should not be used in the exclusion area;
— panes with an overall bow shall be laid on a flat support. This will allow gravity to flatten out the
overall bow and hence give a truer result for the wave or roller wave.
Key
1 straight edge
2 heat strengthened glass
a
Wave or roller wave distortion.
Figure 8 — Measurement of wave or roller wave distortion
6.3.4 Measurement of edge lift (for horizontally heat strengthened glass only)
6.3.4.1 Apparatus
6.3.4.1.1 Straight edge, with a length between 300 mm and 400 mm.
NOTE The actual length of the straight edge required depends on the wavelength of the roller wave.
6.3.4.1.2 Feeler gauges, with various thicknesses in units of 0,05 mm.
6.3.4.2 Method
The glass shall be placed on a flat sup
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 22509
ISO/TC 160/SC 1
Glass in building — Heat strengthened
Secretariat: BSI
soda lime silicate glass
Voting begins on:
2020­04­17
Voting terminates on:
2020­06­12
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 22509:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

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ISO/FDIS 22509:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/FDIS 22509:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Glass products . 2
5 Fracture characteristics . 3
5.1 General . 3
5.2 Fragmentation . 3
6 Dimensions and tolerances . 3
6.1 Nominal thickness and thickness tolerances . 3
6.2 Width and length (sizes) . 4
6.2.1 General. 4
6.2.2 Maximum and minimum sizes . 4
6.2.3 Tolerances and squareness . 4
6.2.4 Edge deformation produced by vertical heat strengthening . 5
6.3 Flatness . 5
6.3.1 General. 5
6.3.2 Measurement of overall bow . 7
6.3.3 Measurement of wave or roller wave distortion . 8
6.3.4 Measurement of edge lift (for horizontally heat strengthened glass only) . 9
6.3.5 Measurement of perimeter deformation of glass produced by air cushion
toughening process . .10
6.3.6 Measurement of local distortion (for vertically heat strengthened glass only) .10
6.3.7 Limitation on overall bow, roller waves and edge lift for horizontally heat
strengthened glass .11
6.3.8 Limitation on overall bow, wave and perimeter deformation for heat
strengthened glass manufactured by air cushion process .12
6.3.9 Limitation on overall bow and local distortion for vertically heat
strengthened glass .12
6.3.10 Other distortions .13
7 Edge work, holes, notches and cut-outs.13
7.1 General .13
7.2 Edge working of glass for heat strengthening .13
7.3 Profiled edges.14
7.4 Round holes .14
7.4.1 General.14
7.4.2 Diameter of holes .14
7.4.3 Limitations on position of holes .14
7.4.4 Tolerances on hole diameters .16
7.4.5 Tolerances on position of holes .16
7.5 Notches and cut­outs .17
7.6 Shaped panes .18
8 Fragmentation test .18
8.1 General .18
8.2 Dimensions and number of test specimens .18
8.3 Test procedure .18
8.4 Assessment of fr agmentation .19
8.5 E valuation of fragmentation .21
8.6 Test report .21
9 Other physical characteristics .21
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ISO/FDIS 22509:2020(E)

9.1 Optical distortion .21
9.1.1 Heat strengthened glass produced by vertical heat strengthening .21
9.1.2 Heat strengthened glass produced by horizontal heat strengthening .21
9.1.3 Heat strengthened glass produced by the air cushion process .22
9.2 Anisotropy (iridescence) .22
9.3 Thermal durability .22
9.4 Mechanical strength .22
9.5 Surface pre­stress .23
10 Marking .23
11 Packaging .23
Annex A (informative) Alternative method for the measurement of roller wave distortion .24
Annex B (informative) Method for the measurement of the surface pre-stress of heat
strengthened glass .26
Bibliography .28
iv © ISO 2020 – All rights reserved

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ISO/FDIS 22509:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non­governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 160, Glass in building, Subcommittee SC 1,
Product considerations.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO/FDIS 22509:2020(E)

Introduction
Heat strengthened soda lime silicate glass has a higher resistance to thermal stress and an enhanced
mechanical strength when compared to annealed glass.
vi © ISO 2020 – All rights reserved

---------------------- Page: 6 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 22509:2020(E)
Glass in building — Heat strengthened soda lime silicate
glass
1 Scope
This document specifies product definitions, product characteristics (i.e. tolerances, flatness,
edgework), fracture characteristics, including fragmentation, and the physical and mechanical
characteristics of flat heat strengthened soda lime silicate glass for use in buildings.
This document does not cover surface finished glasses (e.g. sandblasted, acid etched) after heat
strengthening.
This document does not cover curved (bent) glass.
Other requirements, not specified in this document, can apply to heat strengthened soda lime silicate
glass which is incorporated into assemblies (e.g. laminated glass or insulating glass units), or undergoes
an additional treatment (e.g. coating). The additional requirements are specified in the appropriate
glass product standard. Heat strengthened soda lime silicate glass, in this case, does not lose its
mechanical or thermal characteristics.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 16293­1, Glass in building — Basic soda lime silicate glass products — Part 1: Definitions and general
physical and mechanical properties
ISO 16293­2, Glass in building — Basic soda lime silicate glass products — Part 2: Float glass
ISO 16293­5, Glass in building — Basic soda lime silicate glass products — Part 5: Patterned glass
ISO 11479­1, Glass in building — Coated glass — Part 1: Physical defects
ISO 1288­3, Glass in building — Determination of the bending strength of glass — Part 3: Test with
specimen supported at two points (four point bending)
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:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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3.1
heat strengthened soda lime silicate glass
heat strengthened glass
glass within which a permanent surface compressive stress, additionally to the basic mechanical
strength, has been induced by a controlled heating and cooling process in order to give it increased
resistance to mechanical and thermal stress and prescribed fragmentation characteristics
Note 1 to entry: Thermal durability and mechanical strength are generated by the level of surface compression.
These properties are not size dependent.
3.2
air cushion process
process in which the glass is supported by an air cushion with or without additional rollers
Note 1 to entry: In this process, the glass is between horizontal and 45° of horizontal.
3.3
edge deformation
deformation of the edge caused by the tong marks
3.4
edge lift
edge dip
distortion produced in horizontally heat strengthened glass (3.1), at the leading and trailing edge of the
plate, as a result of the glass during the heat strengthening process not being supported by a roller
Note 1 to entry: This is a distortion produced by a deviation from surface flatness.
3.5
perimeter deformation
distortion around the edge of heat strengthened glass (3.1) manufactured by air cushion process (3.2)
3.6
local distortion
local deformation of vertically heat strengthened glass (3.1) underneath the tong marks
3.7
overall bow
deformation of the whole pane of heat strengthened glass (3.1) caused by the heating and cooling process
3.8
roller wave distortion
periodic deformation produced in horizontally heat strengthened glass (3.1) as a result of the glass
during heat strengthening process being in contact with the rollers
Note 1 to entry: This is a surface distortion produced by a deviation in surface flatness.
3.9
wave distortion
distortion in heat strengthened glass (3.1) manufactured by the air cushion process (3.2) as a result of
the heat strengthening process
4 Glass products
Heat strengthened glass shall be made from a monolithic glass corresponding to ISO 16293­1:
— When float glass is used it shall be in accordance to ISO 16293-2;
— When patterned glass is used it shall be according to ISO 16293-5;
— When coated glass is used it shall be according to ISO 11479­1.
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NOTE There is no international standard for drawn sheet glass. Therefore, see EN 572­4 or national
standards.
Glass nominal thicknesses other than those covered in the above international standards are possible.
5 Fracture characteristics
5.1 General
In the event of breakage, heat strengthened glass fractures in a manner similar to annealed glass (see
Clause 8).
Fragmentation in service may not correspond exactly to that described in Clause 8, due to restraint
from fixing and external actions or due to the cause of fracture.
There can be different fragmentations if heat strengthened glass is used in laminated glass.
NOTE The fracture characteristics of glass are unaffected by temperatures between –50 °C and +100 °C.
5.2 Fragmentation
This test method is employed to demonstrate that heat strengthened glass breaks in the manner
expected of this product. The fragmentation test (see Clause 8) details the fracture pattern, especially
the maximum surface area of “islands”.
This fragmentation behaviour ignores any influence of support conditions and is a representation of
the effect of the surface pre­stress.
6 Dimensions and tolerances
6.1 Nominal thickness and thickness tolerances
The nominal thicknesses and thickness tolerances are those given in the relevant product standards
(see Clause 4), some of which are reproduced in Table 1.
Table 1 — Nominal thicknesses and tolerances
Nominal thickness Float glass tolerances Patterned glass tolerances
mm mm mm
3 ±0,3 ±0,5
4 ±0,3 ±0,5
5 ±0,3 ±0,5
6 ±0,3 ±0,5
8 ±0,6 ±0,8
10 ±0,6 ±1,0
a
12 ±0,8 ±1,5
a
This thickness is only produced by some manufacturers. Therefore, consult the manufacturer for availability.
The thickness of a pane shall be determined as for the basic product. The measurement shall be taken
at the centres of the 4 sides, and away from the area of any tong marks (see Figure 2), which may be
present.
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Figure 1 — Examples of width, B, and length, H, relative to the pane shape
For heat strengthened glass manufactured from patterned glass, the direction of the pattern should be
specified relative to one of the dimensions.
6.2 Width and length (sizes)
6.2.1 General
When tempered safety glass dimensions are quoted for rectangular panes, the first dimension shall
be the width, B, and the second dimension the length, H, as shown in Figure 1. It shall be made clear
which dimension is the width, B, and which is the length, H, when related to its installed position.
For tempered safety glass manufactured from patterned glass, the direction of the pattern should be
specified relative to one of the dimensions.
6.2.2 Maximum and minimum sizes
For maximum and minimum sizes, the manufacturer should be consulted.
6.2.3 Tolerances and squareness
The nominal dimensions for width and length being given, the finished pane shall not be larger than the
nominal dimensions increased by the tolerance, t, or smaller than the nominal dimensions reduced by
the tolerance, t. Limits are given in Table 2.
The squareness of rectangular glass panes is expressed by the difference between its diagonals. The
difference between the two diagonal lengths of the pane of glass shall not be larger than the deviation
limit, v, as specified in Table 3.
Table 2 — Tolerances, t, on width, B, and length, H
Dimensions in millimetres
Tolerance, t
Nominal dimension of side, B or H
Nominal glass thickness, d ≤ 8 Nominal glass thickness, d > 8
≤1 000 ±2 ±3
1 000 < B or H ≤ 2 000 ±3 ±3
2 000 < B or H ≤ 3 000 ±4 ±4
>3 000 ±4 ±5
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Table 3 — Limit deviations, v, for the difference between diagonals
Dimensions in millimetres
Limit deviation, v, on the difference between diagonals
Nominal dimension, B or H
Nominal glass thickness, d ≤ 8 Nominal glass thickness, d > 8
≤ 1 000 4 6
1 000 < B or H ≤ 2 000 6 6
2 000 < B or H ≤ 3 000 8 8
> 3 000 8 10
6.2.4 Edge deformation produced by vertical heat strengthening
The tongs used to suspend the glass during heat strengthening result in surface depressions, known
as tong marks (see Figure 2). The centres of the tong marks are situated up to a maximum of 20 mm in
from the edge. A deformation of the edge less than 2 mm can be produced in the region of the tong mark
and there may also be an area of optical distortion.
Key
1 tong mark
a
Deformation in the tolerances of Table 2.
b
Up to 20 mm.
c
100 mm radius maximum area of optical distortion.
Figure 2 — Tong mark deformation
6.3 Flatness
6.3.1 General
By the very nature of the heat strengthening process, it is not possible to obtain a product as flat as
annealed glass. This difference in flatness depends on the type of glass (e.g. coated, patterned), glass
dimensions, i.e. the nominal thickness, the dimensions, the ratio between the dimensions and the type
of heat strengthening process employed.
There are six kinds of distortion:
a) overall bow (see Figure 3);
b) roller wave distortion (for horizontally heat strengthened glass only) (see Figure 4);
c) edge lift (for horizontally heat strengthened glass only) (see Figure 5);
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d) local distortion (for vertically heat strengthened glass only) (see Figure 6);
e) wave distortion (for air cushion heat strengthened glass only) (see Figure 4);
f) perimeter deformation (for air cushion heat strengthened glass only) (see Figure 10).
NOTE Overall bow, roller wave, edge lift and perimeter deformation can, in general, be accommodated by
the framing system.
Local distortion needs to be allowed for within the glazing materials and the weather seals. For special
requirements, the manufacturers should be consulted.
Key
1 heat strengthened glass
a
Deformation for calculating overall bow.
b
B, or H, or diagonal length.
Figure 3 — Representation of overall bow
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a
Roller wave distortion.
Figure 4 — Representation of wave or roller wave distortion
Key
1 straight edge
2 heat strengthened glass
a
Edge lift.
Figure 5 — Representation of edge lift
Key
1 heat strengthened glass
a
Local distortion.
Figure 6 — Representation of local distortion
6.3.2 Measurement of overall bow
The pane of glass shall be placed in a vertical position and supported on its longer side by two load
bearing blocks at the quarter points (see Figure 7).
For glass thinner than 4 mm nominal thickness, a solid back support with an angle between 3° and 7°
from the vertical can be used.
The deformation shall be measured along the edges of the glass and along the diagonals, as the
maximum distance between a straight metal ruler, or a stretched wire, and the concave surface of the
glass (see Figure 3).
The value for the bow is then expressed as the deformation, in millimetres, divided by the measured
length of the edge of the glass, or diagonal, in millimetres, as appropriate.
The measurement shall be carried out at room temperature.
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Key
1 heat strengthened glass
2 load bearing blocks
a
B or H.
b
(B or H)/2.
c
(B or H)/4.
Figure 7 — Support conditions for the measurement of overall bow
Special care shall be taken for large and thin panes because they may show a buckling which is different
from an overall bow caused by the heat strengthening process. Results from this test method for glasses
thinner than 4mm may be inaccurate.
6.3.3 Measurement of wave or roller wave distortion
6.3.3.1 General
The wave or roller wave distortion is measured by means of a straight edge, or equivalent, being placed
at right angles to the wave or roller wave and bridging from peak to peak of the wave (see Figure 8).
NOTE This section deals with measurement using a straight edge and feeler gauges. An alternative method
is described in Annex A.
6.3.3.2 Apparatus
6.2.3.2.1 A straight edge, with a length between 300 mm and 400 mm.
NOTE The actual length of straight edge required depends on the wavelength of the wave or roller wave.
6.2.3.2.2 Feeler gauges, with various thicknesses in units of 0,05 mm.
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6.3.3.3 Method
Place the straight edge so that it bridges across adjacent peaks. Insert the feeler gauge between the
glass surface and the straight edge. Increase the thickness of the feeler gauges until they just fill the gap
between glass surface and the straight edge. Record the thickness of feeler gauge(s) to an accuracy of
0,05 mm.
Repeat the measurement at several places over the glass surface.
The measured wave or roller wave distortion is the maximum value measured. The maximum allowable
values are given in Table 4 and Table 6.
6.3.3.4 Limitations
The following limitations apply:
— the wave or roller wave can only be measured on panes with a dimension greater than 600 mm
measured at right angles to the waves or roller waves;
— the wave or roller wave cannot be measured in an exclusion area that is 150 mm from the edges of
the pane. The apparatus should not be used in
...