GBT5137.2-1996标准（英文版）.doc

The international standard ISO 3538/DIS-1992 Road vehicles—Safety glazing materials—test methods for optical properties is equivalently adopted for this standard.
1 The subject content and the application scope
This standard regulates the test methods for optical properties of safety glazing materials for road vehicles.
This standard is applicable for the road vehicles—safety glazing materials (hereinafter it is short for safety glazing materials). This kind of safety glazing materials includes the glass products processed by every kind of glass and the glass posed by glass and other materials.
2 Test conditions
Except for the special regulation, the test shall be carried out on the following conditions:
Temperature: 20±5℃;
Atmospheric pressure: ×104~×105Pa;
The relative humidity: 40%~80%.
3 Test methods
Transmittance test
Test purpose
Measure the transmittance of the safety glazing materials.
Sample
The products or the test sheet shall be used, and the test sheet can be obtained from the corresponding test area on the products.
Instruments
Light source: Incandescent bulb, its filament is included in the parallel hexahedron of mm××3mm. The voltage at the two sides of the filament shall keep the color temperature is 2,856±50 K, and this voltage shall be remained within 1/1,000. The instrument used for measuring the voltage shall have the corresponding accuracy.
The optical system: (see figure 1) it posed by two lenses L1 and L2 with the focal length not shorter than 500mm, which are corrected by the color difference. caliber of the lens can not exceed f/20. The distance between the lens L1 and the light source can be adjusted so as to obtain the basically parallel light beam. The A1 diaphragm is installed at one side away from the light source in the area which is100±50mm away from the lens L1, and the diameter of the light beam shall be restricted within 7±1mm. The second A2 diaphragm shall b