1、 Standard Basic Information
GB/Z 39942-2021 "Application of GB/T 20145 to Evaluate the Blue Light Hazards of Light Sources and Luminaires" was released on March 9, 2021
and officially implemented on October 1, 2021. This standard is equivalent to the international standard IEC TR 62778:2014 and is the core guiding
technical document for the blue light hazard assessment of light sources and lamps in China.
2、 Scope of application
Suitable for all lighting products with main radiation energy in the visible light range (380 nm~780 nm), including LED light sources, LED fixtures,
LED modules, metal halide lamps and their fixtures, etc.
3、 Purpose of testing
Assess whether the blue light radiation intensity of the light source and lighting fixtures exceeds the safety threshold, prevent photochemical damage
to the user's retina, and avoid health risks such as vision loss and color vision abnormalities. Blue light typically has a wavelength between 400 nm and
500 nm, with high energy, and can penetrate the cornea and lens directly to the retina. Long term exposure may cause irreversible damage.
4、 Classification of Blue Light Hazard Levels
The standard divides the harm of retinal blue light into four levels, based on the weighted radiance (LB) of blue light:
RG0 (non hazardous/exempt level): LB ≤ 100 W · m ⁻² · sr ⁻¹, will not cause retinal photochemical damage under any foreseeable conditions of use.
RG1 (low hazard): LB ≤ 1 × 10 ⁴ W · m ⁻² · sr ⁻¹, does not pose a hazard under normal exposure conditions and limited usage distance.
RG2 (medium risk): LB ≤ 4 × 10 ⁶ W · m ⁻² · sr ⁻¹, will not cause harm to strong light and temperature discomfort reactions.
RG3 (High Hazard): LB>4 × 10 ⁶ W · m ⁻² · sr ⁻¹, can cause harm in a shorter amount of time.
5、 Core testing conditions
Standard testing distance: 200 mm
Receiving field of view angle: 11 mrad (approximately 0.63 °), simulating the conditions under which the human eye observes an extended light source
Brightness screening: If the brightness of the light source is less than 10000 cd/m ², it can be directly judged as RG0 without further testing
Spectral measurement range: focus on analyzing the weighted radiation of the blue light band from 400 nm to 500 nm
6、 Detection method and judgment process
Detect irradiance or radiance data based on light sources and evaluate according to the following logic:
Measure the spectral radiance of light sources or lamps;
Calculate the blue light weighted radiance LB and blue light weighted irradiance EB;
Compare the measurement results with the exposure limit to determine the risk group;
If it is determined to be RG2, further calculation of the threshold illuminance Ethr and the corresponding minimum safe distance dmin is required to
determine the hazard level under actual usage conditions;
According to the law of conservation of brightness, if the primary light source of LED is RG0 or RG1, the array, module, and finished lighting fixtures
composed of it can directly transmit the corresponding level.
7、 Limit requirements for typical application scenarios
Classroom general lighting fixtures: The blue light hazard group should be RG0;
Local lighting fixtures for writing boards: The blue light hazard group should be RG0 or RG1;
Reading and writing homework desk lamp: The risk group for retinal blue light hazard should be RG0 (unlimited);
LED classroom lights/blackboard lights: Passed the retinal blue light hazard level RG0 exemption certification according to GB/Z 39942-2021.
8、 Certification and Compliance
Certification body: China Quality Certification Center (CQC) implements certification in accordance with the "Blue Light Hazard Level Certification Rules
for Lighting Products";
According to the standard: GB/Z 39942-2021 or IEC 62471-7:2023 can be selected for retinal blue light hazard assessment;
Certificate validity period: 5 years (revised from long-term validity to 5 years in 2023);
Testing report: It needs to be issued by a third-party laboratory with CNAS and CMA qualifications.
9、 Relationship with other standards
GB/Z 39942 is a guiding document at the application level, and its basic methodology is derived from GB/T 20145-2006 (equivalent to CIE S 009/E: 2002)
"Photobiological Safety of Lamps and Lamp Systems". In actual testing, it is necessary to combine the specific provisions on blue light hazards in standards
such as GB/T 9473 (Performance Requirements for Reading and Writing Homework Desk Lamps) and GB 40070 (Hygiene Requirements for Myopia Prevention
and Control of Children and Adolescents' School Supplies).
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