GB/T 43299-2023 PDF in English
GB/T 43299-2023 (GB/T43299-2023, GBT 43299-2023, GBT43299-2023)
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Test methods of electrical heating properties for glazing materials used in power-driven vehicles
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Standards related to (historical): GB/T 43299-2023
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GB/T 43299-2023: PDF in English (GBT 43299-2023) GB/T 43299-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.60
CCS T 34
Test methods of electrical heating properties for glazing
materials used in power-driven vehicles
(ISO 17449:2015, Road vehicles - Safety glazing materials - Test methods for
properties of electrically heated glazing, MOD)
ISSUED ON: NOVEMBER 27, 2023
IMPLEMENTED ON: JUNE 01, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Classification ... 8
5 Sample placement and test conditions ... 8
6 Test items, sample quantity and requirements ... 8
7 Testing ... 9
7.1 Circuit continuity and heating power ... 9
7.2 Driving visibility ... 11
7.3 Electrical attachment pull-out force ... 12
7.4 Electrical attachment bending resistance ... 13
7.5 Hotspots and heating uniformity ... 14
7.6 Defrosting efficiency ... 15
7.7 Overpressure ... 17
7.8 Resistance to low temperature electrical and thermal shock ... 17
7.9 Moisture resistance ... 18
Appendix A (Informative) Technical differences between this document and ISO
17449:2015 and their reasons ... 20
References ... 25
Test methods of electrical heating properties for glazing
materials used in power-driven vehicles
1 Scope
This document describes the test methods of electrical heating properties – circuit
conductivity and heating power, driving visibility, electrical attachment pull-off force,
electrical attachment bending resistance, hotspot and heating uniformity, defrosting
efficiency, overpressure, low temperature electric thermal shock resistance and
moisture resistance – for glazing materials used in power-driven vehicles.
This document applies to the static property test of electrically heated glazing products
and does not represent the properties in the installed state.
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
version corresponding to that date is applicable to this document; for undated references,
the latest version (including all amendments) is applicable to this document.
GB/T 5137.2, Test methods of safety glazing materials used on road vehicles - Part
2: Optical properties tests (GB/T 5137.2-2020, ISO 3538:1997, MOD)
GB/T 13978, Digital multimeters
JJG 124-2005, Verification Regulation of Amperemeters Voltmeters Wattmeters
and Ohmmeters
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
Type-A electrically heated glazing
Electrically heated glazing with heating wires placed on the inner surface of tempered
glass/laminated safety glass/plastic safety glass by silk-screen printing, inkjet or other
methods.
3.2
Keys:
1 – glass;
2 – black border area;
3 – the outermost heating wire at the top;
4 – heating wire;
5 – electrical attachment;
6 – busbar;
7 – the outermost heating wire at the bottom;
8 – heating evaluation area;
L1 – the distance between the outermost heating wires at the top;
L2 – the distance between the outermost heating wires at the bottom.
Figure 1 – Schematic diagram of the heating evaluation area of type-A
electrically heated glazing
3.6
electrical attachment
Component for connecting electrically heated glazing to the vehicle power supply.
3.7
hotspot
The highest temperature point (area) on the outer surface of the sample when the
electrically heated glazing is powered on and heated for a specified time at a specified
ambient temperature.
3.8
defrosting
The electrically heated glazing is heated by inputting the voltage required by the
product specification into the electrical attachment to remove frost on the outer surface
of the glass.
3.9
melting area
Check whether the visibility of the electrically heated glazing used in power-driven
vehicles during driving complies with the requirements of the corresponding product
technical conditions.
This test is only applicable to samples with heated transparent areas.
7.2.2 Test equipment and apparatus
A steel ruler with a graduation value of 0.5 mm, a reading microscope with a graduation
value of 0.001 mm and a tape measure with a graduation value of 1 mm.
7.2.3 Test procedure
For type-A electrically heated glazing, use a reading microscope to measure the width
of the heating wire, use a tape measure to measure the length of the heating wire, and
use a steel ruler to measure the distance between two adjacent heating wires.
For type-B electrically heated glazing, use a reading microscope to measure the width
of the heating wire. When used on windshield glass, the secondary image deviation and
optical distortion of the sample under power-on state shall be tested according to GB/T
5137.2, and the applied voltage and power-on time shall comply with the requirements
of the corresponding product standards or technical conditions.
For type-C electrically heated glazing, the visible light transmittance shall be measured
in accordance with GB/T 5137.2.
7.2.4 Expression of results
For type-A electrically heated glazing, driving visibility is expressed by three values:
the maximum width of the heating wire; the minimum spacing between two adjacent
heating wires; and the ratio of the total area of the opaque heating wires within the
transparent visible area of the heating evaluation area to the area of the transparent
visible area of the heating evaluation area.
For type-B electrically heated glazing, driving visibility is expressed by the width of
the heating wire. When used as a windshield, it is expressed by both the secondary
image deviation and optical distortion under applied voltage.
For type-C electrically heated glazing, driving visibility is expressed in terms of visible
light transmittance.
7.3 Electrical attachment pull-out force
7.3.1 Test purpose
Check whether the electrical attachment meets the requirements of the corresponding
product technical conditions after being subjected to a certain mechanical force.
7.3.2 Test equipment and apparatus
7.3.2.1 Dynamometer
The measurement accuracy is 0.1 N.
7.3.2.2 Stopwatch
The second hand jump value is no more than 0.2 s.
7.3.3 Test procedure
Method A: Apply a specified pulling force perpendicular to the glass surface to the
electrical attachment for 30 seconds unless otherwise specified. After the test, record
the mechanical damage of the connection between the electrical attachment and the
glass, and calculate the heating power.
Method B: Apply a tensile force perpendicular to the glass surface to the electrical
attachment and gradually increase it until the connection between the electrical
attachment and the glass is broken. After the test, record the breaking tensile force value.
7.3.4 Expression of results
Method A uses the heating power and mechanical damage after the test to express the
electrical attachment pull-out force.
Method B uses the breaking tensile force value to express the electrical attachment pull-
out force.
7.4 Electrical attachment bending resistance
7.4.1 Test purpose
Check whether the electrical attachment connected to the glass surface meets the
requirements of the corresponding product technical conditions after being bent a
specified number of times.
This test is only applicable to rigid electrical attachments that need to be bent during
installation.
If there are no special requirements, the test shall be carried out in accordance with
7.4.2.
7.4.2 Test procedure
Bend the electrical attachment forward or backward by 45° ± 2°, and bend it repeatedly
5 times within 8 s ~ 10 s. Figure 3 shows the schematic diagram of the first bending of
upright and bent electrical attachment.
7.6.3 Test procedure
7.6.3.1 Before the test, use alcohol containing methanol or a similar detergent to wipe
the inner and outer surfaces of the sample to thoroughly remove stains on the glass
surface.
7.6.3.2 According to the actual loading conditions, install the sample on the support
frame and place it in the low-temperature box together with the support frame.
7.6.3.3 Before the test, the airflow speed at 300 mm in front of the geometric center of
the sample in the low temperature box shall be tested. The airflow speed shall be less
than 3 km/h. In the absence of special requirements, place the sample in a low
temperature box at -18 ℃ ± 3 ℃ for 1.5 h.
7.6.3.4 The spray nozzle shall be perpendicular to the outer surface of the sample. At a
distance of 200 mm from the sample, spray 0.044 g/cm2 ± 0.004 g/cm2 of water
multiplied by the area of the sample heating evaluation area evenly onto the outer
surface of the sample heating evaluation area. Visually inspect the uniformity of the
frost layer. Spray water onto the sample surface multiple times. Once water can be seen
flowing down the sample surface, stop spraying water and place the sample at -18 ℃ ±
3 ℃ for 5 minutes. Then continue to spray water onto the sample surface until the water
in the sprayer is emptied.
The amount of water shall be prepared in advance according to the required frost layer
thickness, and care shall be taken not to let the water run off and to prevent water from
dripping from the surface of the sample.
7.6.3.5 After water spraying, place the sample at -18 ℃ ± 3 ℃ for 1 hour.
7.6.3.6 Connect the sample to the adjustable DC power supply specified in 7.1.2.1, and
input a voltage that meets the product specification requirements to the power plug. If
there are no special requirements, the setting time shall not exceed 30 minutes. Stop the
test within 1 minute after the surface of the sample heating evaluation area is completely
free of frost (wipers are not used) or when the test setting time is reached, whichever is
shorter. Record the test time and take photos of the sample.
According to the requirements of both the supplier and the buyer, choose whether to
take photos of the samples at certain intervals and record the voltage and current values;
record the time when the surface of the heating evaluation area is completely free of
frost.
7.6.4 Expression of results
If the heating evaluation area is completely frost-free without exceeding the set time,
the defrosting efficiency is 100%. Otherwise, calculate the defrosting efficiency using
the photos that reach the set time.
The temperature measurement accuracy of the low temperature box is 2 ℃.
7.8.3 Test procedure
7.8.3.1 Unless there are special temperature requirements, place the sample in a -30 ℃
± 2 ℃ low temperature box for 4 hours.
7.8.3.2 Connect the electrical attachment to the adjustable DC power supply specified
in 7.1.2.1, so that the electrical attachment input voltage meets the product specification
requirements, and cycle the power on and off 50 times. Each cycle includes 30 minutes
of power on and 30 minutes of power off.
7.8.3.3 After 50 cycles, take the sample out of the low temperature box and place it
under the environmental conditions specified in Chapter 5 for at least 4 hours. Clean
the surface of the sample and check whether there are any breaks, bubbles, cracks or
other defects on the sample.
7.8.3.4 Check the circuit conductivity according to 7.1 and calculate the heating power.
7.8.4 Expression of results
Express the resistance to low-temperature electrical and thermal shock by changes in
the sample's appearance, circuit conductivity and heating power after the test.
7.9 Moisture resistance
7.9.1 Test purpose
Check whether the electrically heated glazing meets the requirements of the
corresponding product technical conditions after being placed in a humid environment
for a period of time.
This test is only applicable to electrically heated glazing with a designed continuous
heating time greater than 30 minutes.
For electrically heated glazing with a design operating temperature below 10 °C, its
moisture resistance shall comply with product specifications.
7.9.2 Test equipment and apparatus
The constant temperature and humidity test chamber has a temperature measurement
accuracy of 2 °C and can maintain a constant test temperature of 23 °C ± 2 °C and
relative humidity of (95±4) %.
7.9.3 Test procedure
7.9.3.1 Place the sample in a constant temperature and humidity test chamber and
maintain the chamber temperature at 23 °C ± 2 °C and relative humidity at (95 ± 4) %.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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