GB/T 43299-2023Test methods of electrical heating properties for glazing materials used in power-driven vehicles (English PDF)

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 °C ± 3 °C 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 °C ±

3 °C 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 °C ± 3 °C 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 °C.

7.8.3 Test procedure

7.8.3.1 Unless there are special temperature requirements, place the sample in a -30 °C

± 2 °C 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) %.

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