ISO 12540:2017
(Main)Glass in building — Tempered soda lime silicate safety glass
Glass in building — Tempered soda lime silicate safety glass
ISO 12540:2017 covers product definitions, product characteristics, i.e. tolerances, flatness, edgework, etc., fracture characteristics, including fragmentation, and the physical and mechanical characteristics of flat tempered soda lime silicate safety glass for use in buildings. ISO 12540:2017 does not cover curved (bent) glass according to ISO 11485. Other requirements, not specified in this document, can apply to thermally toughened soda lime silicate safety glass which is incorporated into assemblies, e.g. laminated glass or insulating glass units, or undergo an additional treatment, e.g. coating. The additional requirements are specified in the appropriate glass product standard. Thermally toughened soda lime silicate safety glass, in this case, does not lose its mechanical or thermal characteristics.
Verre dans la construction — Verre silico-sodo-calcique de sécurité trempé
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 12540
First edition
2017-03
Glass in building — Tempered soda
lime silicate safety glass
Verre dans la construction — Verre silico-sodo-calcique de sécurité
trempé
Reference number
ISO 12540:2017(E)
©
ISO 2017
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ISO 12540:2017(E)
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© ISO 2017, Published in Switzerland
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ISO 12540:2017(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Glass products . 3
5 Fracture characteristics . 3
5.1 General . 3
5.2 Accidental human impact . 3
5.3 Fragmentation . 3
6 Dimensions and tolerances . 4
6.1 Nominal thickness and thickness tolerances . 4
6.2 Width and length (sizes) . 4
6.2.1 General. 4
6.2.2 Maximum and minimum sizes . 5
6.2.3 Tolerances and squareness . 5
6.2.4 Edge deformation produced by vertical tempering . 5
6.3 Flatness . 6
6.3.1 General. 6
6.3.2 Measurement of overall bow . 8
6.3.3 Measurement of wave or roller wave distortion . 9
6.3.4 Measurement of edge lift (for horizontally tempered safety glass only) .10
6.3.5 Measurement of perimeter deformation of glass produced by air cushion
toughening process . .11
6.3.6 Measurement of local distortion (for vertically tempered safety glass only) .12
6.3.7 Limitation on overall bow, roller waves and edge lift for horizontally
tempered safety glass .12
6.3.8 Limitation on overall bow, wave and perimeter deformation for tempered
safety glass manufactured by air cushion process .13
6.3.9 Limitation on overall bow and local distortion for vertically tempered
safety glass .13
6.3.10 Other distortions .14
7 Edge work, holes, notches and cut-outs.14
7.1 General .14
7.2 Edge working of glass for tempering .14
7.3 Profiled edges.15
7.4 Round holes .15
7.4.1 General.15
7.4.2 Diameter of holes .15
7.4.3 Limitations on position of holes .15
7.4.4 Tolerances on hole diameters .17
7.4.5 Tolerances on position of holes .17
7.5 Holes/others .18
7.6 Notches and cut-outs .18
7.7 Shaped panes .19
8 Fragmentation test .19
8.1 General .19
8.2 Dimensions and number of test specimens .19
8.3 Test procedure .19
8.4 Assessment of fragmentation .20
8.5 Minimum values from the particle count .21
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ISO 12540:2017(E)
8.6 Selection of the longest particle .22
8.7 Maximum length of the longest particle .22
8.8 Test report .22
9 Other physical characteristics .22
9.1 Optical distortion .22
9.1.1 Tempered safety glass produced by vertical tempering .22
9.1.2 Tempered safety glass produced by horizontal tempering .22
9.2 Anisotropy (iridescence) .22
9.3 Thermal durability .23
9.4 Mechanical strength .23
9.5 Surface pre-stress .23
10 Marking .24
11 Packaging .24
Annex A (normative) Pendulum impact test methods .25
Annex B (informative) Alternative method for the measurement of roller wave distortion .26
Annex C (informative) Example of particle count .28
Annex D (informative) Method for the measurement of the surface pre-stress of tempered
safety glass .31
Bibliography .33
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ISO 12540:2017(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.
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URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by ISO/ TC 160, Glass in building, Subcommittee SC 1, Product considerations.
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ISO 12540:2017(E)
Introduction
Tempered soda lime silicate safety glass has a breakage behaviour that is different to annealed glass.
This behaviour is a direct result of the high surface pre-stress.
Tempered soda lime silicate safety glass has a known behaviour under accident human impact together
with known mechanical and thermal stress resistance.
NOTE 1 ISO/TC 160/SC 2 produces standards for the determination of the design strength of glass and is
preparing a design method.
NOTE 2 In Europe, the term “thermally toughened” is used instead of “tempered”.
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INTERNATIONAL STANDARD ISO 12540:2017(E)
Glass in building — Tempered soda lime silicate safety glass
1 Scope
This document covers product definitions, product characteristics, i.e. tolerances, flatness, edgework,
etc., fracture characteristics, including fragmentation, and the physical and mechanical characteristics
of flat tempered soda lime silicate safety glass for use in buildings.
This document does not cover curved (bent) glass according to ISO 11485.
Other requirements, not specified in this document, can apply to thermally toughened soda lime
silicate safety glass which is incorporated into assemblies, e.g. laminated glass or insulating glass
units, or undergo an additional treatment, e.g. coating. The additional requirements are specified in the
appropriate glass product standard. Thermally toughened soda lime silicate safety 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
1)
ISO 16293-2:— , Glass in building — Basic soda lime silicate glass products — Part 2: Float glass
1)
ISO 16293-5:— , Glass in building — Basic soda lime silicate glass products — Part 5: Patterned glass
ISO 29584, Glass in building — Pendulum impact testing and classification of safety 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:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
flat tempered safety glass
tempered (thermally toughened) glass which has not been deliberately given a specific profile during
manufacture
1) Under preparation.
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ISO 12540:2017(E)
3.2
enamelled tempered safety glass
tempered (thermally toughened) glass which has a ceramic frit fired into the surface during the
tempering (toughening) process
Note 1 to entry: After tempering, the ceramic frit becomes an integral part of the glass.
Note 2 to entry: The application of the ceramic frit may be by a continuous application or discontinuous, e.g.
screen printing.
3.3
horizontal process
process in which the glass is supported on horizontal rollers
3.4
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 will be between horizontal and 45° of horizontal.
3.5
vertical process
process in which the glass is suspended by tongs
3.6
edge deformation
deformation of the edge caused by the tong marks
3.7
edge lift
distortion produced in horizontally tempered safety glass, at the leading and trailing edge of the plate,
as a result of the glass during the tempering (toughening) process not being supported by a roller
Note 1 to entry: This is a distortion produced by a deviation from surface flatness.
Note 2 to entry: Also referred to as edge dip.
3.8
perimeter deformation
distortion around the edge of tempered safety glass manufactured by air cushion process
3.9
local distortion
local deformation of vertically tempered safety glass underneath the tong marks
3.10
overall bow
deformation of the whole pane of tempered safety glass caused by the heating and cooling process
3.11
roller wave distortion
periodic distortion produced in horizontally tempered safety glass as a result of the glass during
tempering process being in contact with the rollers
Note 1 to entry: This is a surface distortion produced by a reduction in surface flatness.
3.12
wave distortion
distortion in tempered safety glass manufactured by the air cushion process as a result of the
tempering process
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ISO 12540:2017(E)
4 Glass products
Tempered safety glass is made from a monolithic glass generally corresponding to one of the following
standards:
— basic soda lime silicate glass products according to ISO 16293-1;
— float glass according to ISO 16293-2;
— patterned glass according to ISO 16293-5;
— coated glass according to ISO 11479-1.
NOTE For drawn sheet glass, an ISO standard is not available. Therefore, see EN 572–4 or national standards.
Other nominal thicknesses of glass than those covered in the above standards are possible.
5 Fracture characteristics
5.1 General
In the event of breakage, tempered safety glass fractures into numerous small pieces, the edges of
which are generally blunt.
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.
5.2 Accidental human impact
5.2.1 When subjected to an accidental human impact, tempered safety glass will either not break or
break in a manner that will reduce the risk of cutting and piercing injuries.
5.2.2 Tempered safety glass can be classified by the use of a pendulum impact test. When tested by this
type of test, the safe breakage criteria employed for tempered safety glass is that the 10 largest crack free
2
particles collected within 3 min after impact shall weigh no more than the mass equivalent of 6 500 mm
of the original test piece.
5.2.3 The quoted break criteria is taken from the standards given in Annex A. Annex A lists the test
methods presently employed to classify this product.
NOTE The safe breakage criteria are different from the fragmentation criteria used to determine that the
product complies with its definition.
5.3 Fragmentation
This test method is employed to demonstrate that the tempered safety glass breaks in the manner
expected of this product. The fragmentation test (see Clause 8) details the minimum number of crack-
free particles that shall be in a set area, i.e. 50 mm × 50 mm, and the dimension of the largest acceptable
splinter.
This fragmentation behaviour ignores any influence of support conditions and is a representation of
the effect of the surface pre-stress.
These properties are not size dependent.
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ISO 12540:2017(E)
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).
Table 1 — Nominal thicknesses and tolerances
Nominal thickness Float glass tolerances Patterned glass tolerances
mm mm mm
2 ±0,2 Not manufactured
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
12 ±0,8 ±1,5
15 ±0,8 ±1,5
19 ±1,2 ±1,5
22 ±1,2 ±2,0
25 ±1,2 Not manufactured
The thickness of a pane shall be determined as for the basic product. The measurement shall be taken
at the centre of the four sides, and away from the area of any tong marks (see Figure 2), which may be
present.
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.
Figure 1 — Examples of width, B, and length, H, relative to the pane shape
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ISO 12540:2017(E)
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
Nominal glass thickness
Nominal dimension
of side, B or H
2 3 4 5 6 8 10 12 15 19 25
≤ 1 000 ±2 ±3 ±4 ±5
1 000 < B or H ≤ 2 000 ±3 ±4 ±5
2 000 < B or H ≤ 3 000 ±4 ±6
3 000 < B or H ±4 ±5 ±6
Table 3 — Limit deviations, v, for the difference between diagonals
Dimensions in millimetres
Nominal glass thickness
Nominal dimension
of side, B or H
2 3 4 5 6 8 10 12 15 19 25
≤ 1 000 4 6 8 10
1 000 < B or H ≤ 2 000 6 8 10
2 000 < B or H ≤ 3 000 8 12
3 000 < B or H 8 10 12
6.2.4 Edge deformation produced by vertical tempering
The tongs used to suspend the glass during tempering 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 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.
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ISO 12540:2017(E)
Key
1 deformation in the tolerances of Table 2
2 up to 20 mm
3 tong mark
4 100 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 tempering 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, etc., glass
dimensions, i.e. the nominal thickness, the dimensions, the ratio between the dimensions and the type
of the tempering process employed.
There are six kinds of distortion:
a) overall bow (see Figure 3);
b) roller wave distortion (for horizontally tempered safety glass only) (see Figure 4);
c) edge lift (for horizontally tempered safety glass only) (see Figure 5);
d) local distortion (for vertically tempered safety glass only) (see Figure 6).
Local distortion needs to be allowed for within the glazing materials and the weather seals. For
special requirements, the manufacturers should be consulted.
e) wave distortion (for air cushion–tempered safety glass only) (see Figure 4);
f) perimeter deformation (for air cushion–tempered safety glass only) (see Figure 10).
NOTE Overall bow, roller wave, edge lift and perimeter deformation can, in general, be accommodated by
the framing system.
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ISO 12540:2017(E)
Key
1 deformation for calculating overall bow
2 B, or H, or diagonal length
3 tempered safety glass
Figure 3 — Representation of overall bow
Key
1 roller wave distortion
Figure 4 — Representation of wave or roller wave distortion
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ISO 12540:2017(E)
Key
1 straightedge
2 edge lift
3 tempered safety glass
Figure 5 — Representation of edge lift
Key
1 local distortion
2 tempered safety glass
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 12540:2017(E)
Dimensions in millimetres
Key
1 B or H
2 (B or H)/2
3 (B or H)/4
4 tempered safety glass
5 load-bearing blocks
Figure 7 — Support conditions for the measurement of overall bow
NOTE Special care needs to be taken for large and thin panes because they can show a buckling which is
different from an overall bow caused by the tempering process. Results from this test method for glasses thinner
than 4 mm can 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 straightedge, or equivalent, b
...
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