ISO 3537:2015

INTERNATIONAL ISO
STANDARD 3537
Fourth edition
2015-04-15
Road vehicles — Safety glazing
materials — Mechanical tests
Véhicules routiers — Vitrages de sécurité — Essais mécaniques
Reference number
ISO 3537:2015(E)
©
ISO 2015

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ISO 3537:2015(E)

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© ISO 2015
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Published in Switzerland
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ISO 3537:2015(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions . 1
5 Application of tests. 1
6 227 g ball test . 1
6.1 Principle . 1
6.2 Apparatus . 1
6.3 Test piece . 3
6.4 Procedure . 3
6.5 Expression of results . 3
7 2 260 g ball test . 3
7.1 Principle . 3
7.2 Apparatus . 4
7.3 Test piece . 4
7.4 Procedure . 4
7.5 Expression of results . 4
8 Abrasion resistance test . 4
8.1 Principle . 4
8.2 Apparatus . 4
8.3 Test pieces . 7
8.4 Standardization of abrading wheels . 7
8.5 Procedure . 8
8.6 Expression of results .10
9 Fragmentation test .10
9.1 Principle .10
9.2 Apparatus .11
9.3 Procedure .11
9.4 Expression of results .12
10 Head-form test .13
10.1 Principle .13
10.2 Apparatus .13
10.3 Procedure .15
10.3.1 Tests on flat test piece .15
10.3.2 Tests on complete windscreen .15
10.4 Expression of results .16
Annex A (informative) Vacuum pick-up nozzle modification .17
Annex B (informative) Calibration verification of Taber abraser .18
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ISO 3537:2015(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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 35, Lighting
and visibility.
This fourth edition cancels and replaces the third edition (ISO 3537:1999), which has been technically
revised.
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INTERNATIONAL STANDARD ISO 3537:2015(E)
Road vehicles — Safety glazing materials — Mechanical tests
1 Scope
This International Standard specifies mechanical test methods relating to the safety requirements for
all safety glazing materials in a road vehicle, whatever the type of glass or other material of which they
are composed.
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.
ISO 48, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD
and 100 IRHD)
ISO 3536, Road vehicles — Safety glazing materials — Vocabulary
ISO 15082, Road vehicles — Tests for rigid plastic safety glazing materials
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3536 apply.
4 Test conditions
Unless otherwise specified, the tests shall be carried out under the following conditions:
— Ambient temperature: 20 °C ± 5 °C;
— Atmospheric pressure: 86 kPa to 106 kPa (860 mbar to 1 060 mbar);
— Relative humidity: (60 ± 20) %.
5 Application of tests
For certain types of safety glazing materials, it is not necessary to carry out all the tests specified in this
International Standard.
6 227 g ball test
Rigid plastic safety glazing materials can alternatively be tested in accordance with ISO 15082.
6.1 Principle
Determination of whether the safety glazing material has a certain minimum strength and cohesion
under impact from a small hard object.
6.2 Apparatus
6.2.1 Hardness steel ball, with a mass of 227 g ± 2 g and a diameter of approximately 38 mm.
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ISO 3537:2015(E)

6.2.2 Means for dropping the ball freely from a height to be specified, or means for giving the ball
a velocity equivalent to that obtained by the free fall.
When a device to project the ball is used, the tolerance on velocity shall be ±1 % of the velocity equivalent
to that obtained by the free fall.
6.2.3 Supporting fixture, such as that shown in Figure 1, composed of two steel frames, with machined
borders, 15 mm wide, fitting one over the other and faced with rubber gaskets about 3 mm thick and
15 mm wide, of hardness 50 IRHD, determined in accordance with ISO 48.
The lower frame rests on a steel box, about 150 mm high. The test piece is held in place by the upper
frame, the mass of which is about 3 kg. The supporting frame is welded on a sheet of steel about 12 mm
thick, resting on the floor, with an interposed sheet of rubber, about 3 mm thick, of hardness 50 IRHD.
Dimensions in millimetres
Key
1 test piece
2 rubber gasket
3 sheet of rubber
Figure 1 — Support for ball tests
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ISO 3537:2015(E)

6.3 Test piece
+10
The test piece shall be a flat square with 300 mm mm sides or shall be cut out from the flattest part
0
of a windscreen or other curved safety glazing material.
Alternatively, the whole windscreen or other finished safety glazing products can be tested, using the
supporting fixture according to 6.2.3. In the case of curved test pieces, care shall be taken to ensure
adequate contact between the safety glazing material and the support.
6.4 Procedure
Temperature of test pieces: Ambient temperature.
The 227 g ball test can alternatively be carried out on test pieces at −20 °C ± 2 °C or +40 °C ± 2 °C if specified.
Condition the test piece at the specified temperature for at least 4 h immediately preceding the test. If
the specified test temperature is −20 °C or + 40 °C, the periods according to Table 1 between the removal
of the test pieces from tempering and the release of the ball shall not be exceeded.
Table 1 — Period between the removal of the test piece from the temperature control unit
and the release of the ball
Test piece thickness, e Maximum interim period at Maximum interim period at
mm test temperature −20 °C test temperature + 40 °C
2,5 ≤ e ≤ 4,5 0 min 40 s 2 min 0 s
4,5 < e ≤ 6,5 1 min 0 s 2 min 0 s
6,5 < e ≤ 8,5 1 min 25 s 2 min 0 s
e > 8,5 1 min 40 s 2 min 0 s
If the test piece is less than 2,5 mm thick, then the test shall be carried out immediately at the given
temperature.
Place the test piece in the fixture (6.2.3). The plane of the test piece shall be perpendicular, within 3°,
to the incident direction of the ball. When necessary to retain the test piece in the fixture, it shall be
clamped to ensure that the movement of the test piece during test shall not exceed 2 mm at any point
along the inside periphery of the fixture.
The point of impact shall be within 25 mm of the geometric centre of the test piece for a drop height less
than or equal to 6 m, and within 50 mm of the centre of the test piece for a drop height greater than 6 m.
The ball shall strike the face of the test piece which represents the outside face of the safety glazing
material when mounted on the vehicle. The ball shall be allowed to make only one impact.
6.5 Expression of results
Assess the type and extent of damage to the test piece. If fragments are detached from the test piece, the
total mass of the fragments and the mass of the largest fragment, detached from the side remote from
impact, shall be weighed to the nearest 0,1 g. Report the drop height and temperature for each test piece
and whether the test piece supported or did not support the 227 g ball.
7 2 260 g ball test
Rigid plastic safety glazing materials may alternatively be tested in accordance with ISO 15082.
7.1 Principle
Evaluation of the penetration resistance of the safety glazing material.
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ISO 3537:2015(E)

7.2 Apparatus
7.2.1 Hardened steel ball, with a mass of 2 260 g ± 20 g and a diameter of approximately 82 mm.
7.2.2 Means for dropping the ball freely from a height to be specified, or means for giving the ball
a velocity equivalent to that obtained by the free fall.
When a device to project the ball is used, the tolerance on velocity shall be ±1 % of the velocity equivalent
to that obtained by the free fall.
7.2.3 Supporting fixture, as described in 6.2.3.
7.3 Test piece
+10
The test piece shall be a flat square with 300 mm sides or shall be cut out from the flattest part of a
0
windscreen or other curved safety glazing material.
Alternatively, the whole windscreen or other finished safety glazing products can be tested, using the
supporting fixture according to 6.2.3. In the case of curved test pieces, care shall be taken to ensure
adequate contact between the safety glazing material and the support.
7.4 Procedure
Condition the test piece at the specified temperature for at least 4 h immediately preceding the test.
Place the test piece in the fixture (6.2.3). The plane of the test piece shall be perpendicular, within 3°, to
the incident direction of the ball. When necessary to retain the test piece in the fixture, the test piece in
the fixture shall be clamped to ensure that the movement of the test piece during test shall not exceed
2 mm at any point along the inside periphery of the fixture.
The point of impact shall be within 25 mm of the geometric centre of the test piece. The ball shall strike
the face of the test piece which represents the internal face of the safety glazing material when mounted
on the vehicle. The ball shall be allowed to make only one impact.
7.5 Expression of results
If the ball passes completely through the test piece within 5 s after the impact, the result shall be recorded
as a “penetration”. If the ball remains on top of the test piece, or wedged in a hole, for 5 s or more, the
result shall be recorded as a “support”. Report the drop height and temperature for each test piece.
8 Abrasion resistance test
Test rigid plastic safety glazing materials in accordance with ISO 15082.
8.1 Principle
Determination of whether the safety glazing material has a certain minimum resistance to abrasion at
ambient temperature.
8.2 Apparatus
1)
8.2.1 Abrading instrument , shown diagrammatically in Figure 2, and consisting of the following:
1) A suitable abrading instrument is supplied by Taber Industries (USA). This information is given for the
convenience of users of this International Standard and does not constitute an endorsement by ISO of the product
named. Equivalent products can be used if they can be shown to lead to the same results.
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ISO 3537:2015(E)

— A horizontal turntable and centre clamp which revolves counter-clockwise at a fixed speed of
60 r/min ± 2 r/min or 72 r/min ± 2 r/min.
— Two weighted parallel arms, each carrying a special abrasive wheel freely rotating on a ball bearing
horizontal spindle; each wheel rests on the test piece under the pressure exerted by a mass of 500 g,
unless otherwise specified.
— A vacuum suction system (not depicted in Figure 2) and vacuum pick-up nozzle to remove debris
and abrasive particles from the test piece surface during testing. The height of the vacuum pick-up
nozzle shall be adjustable, and the nozzle openings shall have a diameter of 11 mm.
In the case of a nominal nozzle opening equal to 8 mm, the nozzle openings shall be enlarged to 11 mm
following the instructions shown in Annex A, or by installation of a replacement nozzle with 11 mm openings.
The turntable of the abrading instrument shall rotate regularly, substantially in one plane (the deviation
from this plane shall not be greater than ±0,05 mm at a distance of 1,6 mm from the turntable periphery).
The wheels shall be mounted in such a way that when they are in contact with the rotating test piece,
they rotate in contrary directions so as to exert a compressive and abrasive action along curved lines
2
over an annular area of about 30 cm , twice during each rotation of the test piece.
Verify calibration of the abrading instrument as directed by the equipment manufacturer. For one Taber
abraser, see Annex B.
Figure 2 — Diagram of abrading instrument
2)
8.2.2 Abrasive wheels having a cylindrical shape and composed of a resilient binder and abrasive
particles such as aluminium oxide and silicon carbide particles. The abrasive particles shall have a particle
size between 20 microns and 102 microns and uniform distribution throughout the resilient binder. Each
wheel shall be moulded to a hub which includes an axial hole 16,0 mm ± 0,1 mm, allowing the wheels to
be mounted to the flange holder on the abraser arms. The sides of the wheel shall be parallel, and each
wheel shall be 12,7 mm ± 0,3 mm wide and have an external diameter of less than 52,5 mm and in no case
less than 44,4 mm. If a different wheel has been used, which has been documented to produce equivalent
results, the description of the wheel shall be included with the results.
The abrasive wheel shall be such that the light scatter resulting from abrading [final haze minus initial
haze (8.6)] of each of three float glass samples subjected to 1 000 cycles of abrasion is within 0,7 % ± 0,5 %.
2) Such as Calibrase CS-10F wheels available from Taber Industries (USA) or C180 OXF wheels available from
DAIWA Kasei Kogyo (Japan). This information is given for the convenience of users of this International Standard
and does not constitute an endorsement by ISO of the products named. Equivalent products can be used if they can
be shown to lead to the same results.
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ISO 3537:2015(E)

The float glass shall be 3 to 4 mm in thickness and of at least 70 % luminance transmittance. Abrasion
should be conducted on the upper glass side (air or fire side).
8.2.3 Refacing stone. The fine side of a Taber ST-11 refacing stone (or equivalent) shall be used for
resurfacing the abrasive wheels. It is important that the turntable platform runs true on the abraser and
that the refacing stone lies flat on the turntable platform.
3)
8.2.4 Hazemeter , shown diagrammatically in Figure 3 and consisting of the following:
— A light source and a photodetector, and the combination shall be filtered to provide an output
corresponding to the luminosity response of the 1931 CIE Standard Colourimetric Observer with
CIE Standard Illuminant C or, alternatively, Illuminant A. The output shall be proportional to within
1 % to the incident flux over the range of flux used. The photometric stability for source and detector
shall be constant throughout the test of each test piece (specimen).
— An integrating sphere to collect transmitted flux; the sphere can be of any diameter as long as the
total port areas do not exceed 4,0 % of the internal reflecting area of the sphere. The entrance and
exit ports shall be centred on the same great circle of the sphere, and there shall be at least 2,97 rad
(170°) of arc between centres. The exit port shall subtend an angle of 0,14 rad (8°) at the centre of
the entrance port. With the light trap in position, without the test piece, the axis of the irradiating
beam shall pass through the centres of the entrance and exit ports. For a hazemeter, position the
photocell or photocells on the sphere 1,57 rad ± 0,17 rad (90° ± 10°) from the entrance port and
baffle it from direct exposure to the entrance port. In the pivotable modification where the interior
wall adjacent to the exit port is used as the reflectance reference, the angle of rotation of the sphere
shall be 0,140 rad ± 0,008 rad (8,0° ± 0,5°).
Illuminate the test piece by a substantially unidirectional beam; the maximum angle that any ray of this
beam can make with the beam axis shall not exceed 0,05 rad (3°). This beam shall not be vignette at
either port of the sphere.
When the test piece is placed against the entrance port of the integrating sphere, the angle between the
perpendicular to the test piece and a line connecting the centres of entrance and exit ports shall not
exceed 0,14 rad (8°).
An aperture or diaphragm shall be centrally inserted in the haze measuring apparatus to centre the
light beam on the abradant track and limit it to a diameter of 7 mm ± 1 mm at the test piece.
When the reduced light is unobstructed by a test piece, its cross section at the exit port shall be
approximately circular, sharply defined, uniformly bright, and concentric within the exit port, leaving
an annulus of 0,023 rad ± 0,002 rad (1,3° ± 0,1°) subtended at the entrance port.
The surfaces of the interior of the integrating sphere, baffles, and reflectance standard, if used, shall be
of equal reflectance, matte, and highly reflecting throughout the visible spectrum.
A light trap shall be provided that will absorb the beam completely when no test piece is present, or the
instrument design shall obviate the need for a light trap.
Forward scattering glass standards can be used to check that the optical system of the hazemeter is
properly adjusted.
3) A suitable instrument for measuring haze is supplied by BYK-Gardner (USA). This information is given for the
convenience of users of this International Standard and does not constitute an endorsement by ISO of the product
named. Equivalent products can be used if they can be shown to lead to the same results.
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ISO 3537:2015(E)

4
23
5
1
8
6
9
7
10
Key
1 condenser 6 source
2 entrance window 7 aperture
3 filter 8 lens
4 photo detector 9 specimen
5 light trap (if used) 10 reflectance standard
NOTE Dotted lines show position of reflectance standard for total transmittance measurement.
Figure 3 — Hazemeter
8.2.5 Test piece holder. A suitable holder shall be used to permit positioning the abraded test piece
on the hazemeter so that the light beam is centred in the abraded track and the test piece is flush at the
measurement port.
Calibrate the hazemeter with the test piece holder before the initial measurement of the haze with no
test piece present and verify that the reading of the hazemeter is zero.
The whole apparatus shall be checked at regular intervals by means of calibration standards of defined haze.
If haze measurements are made using equipment or methods differing from the above, the results shall
be corrected in order to be in agreement with those obtained by the apparatus described above.
8.3 Test pieces
The test pieces shall be flat squares with 100 mm sides having both surfaces substantially plane and
parallel, and optionally with a 6,3 mm diameter fixing hole drilled in the centre.
8.4 Standardization of abrading wheels
To ensure that the abrading function of the wheels is maintained at a constant level, prepare the
abrading wheels prior to each test. Mount the wheels on their respective flange holders, taking care not
to handle them by their abrasive surfaces. Select the load to be used and affix it to the abraser. If no load
is specified, use a load of 500 g (per wheel). Mount a Taber ST-11 refacing stone (or equivalent) on the
turntable, fine side up, and secure using the nut.
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ISO 3537:2015(E)

Lower the vacuum nozzle and adjust its height to 1 mm above the refacing stone surface with a gage
having a thickness equal to 1 mm or a gage pin having a diameter equal to 1 mm. After setting the height
of the vacuum nozzle, ensure the rear vacuum nozzle does not contact the refacing stone. Set the vacuum
suction force so that a residual pressure of 13,7 kPa (137 millibar) or lower results. Lower the arms so
the wheels contact the surface of the ST-11 refacing stone. Reface the wheels for 25 cycles.
After refacing, use a soft bristle, anti-static brush to lightly brush the wheel surfaces to remove any
loose particulate matter. A brush found suitable for this purpose is a soft-fibre, static-dissipative brush
manufactured from an acrylic fibre (0,04 mm filament diameter) that has been chemically bonded with
−4
a layer of copper sulphide to produce an electrical resistance of 3 − 5 × 10 ohms per centimetre.
New wheels or wheels trued using a diamond tool refacer (such as Taber Diamond Wheel Refacer, or
equivalent), shall firstly be broken in with 100 cycles on the fine side of the ST-11 refacing stone
...