1、 Standard positioning
GB/T 20145-2006 "Photobiological Safety of Lamps and Lamp Systems" is a national recommended standard for photobiological safety of lighting products in China. It was released in 2006, implemented in November of the same year, and will continue to be valid for review in 2024. The core problem it solves is: under what conditions the light radiation emitted by the lamp and lamp system can cause damage to the human eye and skin, and how to classify and control it.
2、 International Correspondence
The standard is equivalent to the International Commission on Illumination standard CIE S 009/E: 2002, and the technical content is the same as the IEC 62471 system. Therefore, in export certification, GB/T 20145 is often used as an acceptable national difference standard, and domestic testing reports are basically consistent with international testing logic.
3、 Scope of application and exclusion items
Coverage: All incoherent broadband electric light sources and lighting systems, including LED, OLED, incandescent, fluorescent, halogen, stage lights, display screens, car lights, phototherapy equipment, etc.
Wavelength range: 200 nm to 3000 nm, covering the entire spectrum from ultraviolet, visible to infrared.
Clear exclusion: Laser products (under the jurisdiction of IEC 60825/GB 7247 series).
4、 Two types of physical quantities evaluated
Irradiance (W/m ²): The radiation power received per unit area, used to evaluate the level of exposure to the skin, cornea, and lens.
Radiance (W · m ⁻² · sr ⁻¹): The radiation intensity per unit area and unit solid angle, used to evaluate the harm of imaging on the retina, and is the main parameter for blue light evaluation.
Observe the radiance with a large light source and the irradiance with a small light source; Testing requires binding three elements: distance, field of view, and exposure time.
5、 Four types of photobiological hazards
Skin and eye photochemical UV hazards (200-400 nm): Evaluate the risk of erythema, photoaging, and corneal damage.
Near ultraviolet harm to the eyes (315-400 nm): targeting long-term cumulative damage to the crystalline lens.
Retinal blue light photochemical hazard (300-700 nm): The most concerning issue for LED products is the weighted radiance in the 400-500 nm wavelength range.
Retinal thermal hazards and infrared/skin thermal hazards (380-3000 nm): High power light sources, halogen lamps, therapy lamps, and stage lamps are specifically assessed for thermal effects.
6、 Risk grouping (RG grading)
Divided into four levels based on the maximum allowable exposure time t_max:
RG0 exemption level: No harm under any foreseeable use, preferred for ordinary household lighting.
RG1 low risk: safe under normal use, no special protection required.
Risk in RG2: Protection can be achieved through avoidance reactions, but there is a risk of prolonged exposure and warning signs are required.
RG3 High Risk: Very short exposure can cause injury, limited to professional/enclosed environments, not suitable for general lighting.
Consumer lighting usually requires ≤ RG1; Reading and writing desk lamps, classroom lights, and other long-term close range scenes often require RG0.
7、 Blue Light Special and Supporting Standards
The blue light weighted radiance LB is the core criterion: RG0 limit ≤ 100 W · m ⁻² · sr ⁻¹, RG1 ≤ 1 × 10 ⁴, RG2 ≤ 4 × 10 ⁶.
The commonly used evaluation distance is at a distance of 500 lx and not less than 200 mm, with a receiving field of view angle of 0.011 rad (approximately 0.63 °).
The evaluation of blue light transmission at the lamp end is undertaken by GB/Z 39942-2021 (equivalent to IEC TR 62778), which solves the problem of "how to transfer lamp bead data to the entire lamp".
8、 Usage in Engineering and Compliance
Product admission: LED lighting fixtures, display screens, UV nail lamps, red light therapy devices, and stage lights are often based on this standard for factory photobiological safety reports.
Strong standard linkage: GB 7000.1 General safety of lighting fixtures has been included in the requirements for photobiological safety; Classroom lighting, reading and writing desk lamps, and other subdivision strong standards directly refer to RG level as the qualified line.
Selection judgment: When purchasing, refer to the RG group in the report instead of the merchant claiming to have "no blue light hazard"; RG0 ≠ zero blue light, but the risk is negligible under foreseeable use.
In summary, GB/T 20145 is a national method that uses irradiance/radiance to convert the question of whether a lamp will harm the eyes or skin into a measurable and graded method. RG0 to RG3 are its output conclusions.
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