Standards for Eye Safety and Luminaires

Radiation emitted by lamps, luminaires and other artificial light sources can present hazards to skin and eyes. Only the skin and eyes are affected as optical radiation does not penetrate deep into tissues.

Luminaire manufacturers need to ensure products present no photobiological hazards (the undesirable effects of optical radiation on human tissue).

Optical radiation is a type of electromagnetic radiation in the wavelength range between 100 nm and 1 mm, comprising of ultraviolet radiation, visible radiation and infrared radiation.

Wavelengths of different optical radiation from artificial sources of light.

The effects on the eyes and skin of exposure to optical radiation varies depending on the wavelength and intensity. It can have harmful consequences as shown in the table.

Due to their possible photobiological hazard, regulators’ are paying particular attention to LED light sources which have increasingly become the most popular source of lighting, due to their high efficiency, cost and longevity. Also, the inclusion of LED technology in several applications such as smart TVs, computer screens and smart phone backlighting, means that we are becoming more and more exposed to such lighting.

Wavelengths of optical radiation from artificial sources of light

Bioeffect of optical radiation

Bioeffect of optical radiation

While the content of UV in LEDs for general purpose lighting are not usually found to be a concern, there is a notably high concentration of blue light in its spectrum that poses a risk of photoretinitis (by photo chemical reaction on the retina) and retinal thermal hazard excess, which can both be severely detrimental to the eyesight.

Shown below is a typical spectrum of a cool white LED light, clearly having the highest peak of blue light radiation which penetrates the cornea of the eye and gets focused on the retina by the eye lens. The hazard is dependent upon the size of the source and maximum limits are expressed in terms of radiance.

The applicable standard for determining photobiological safety of lamps and systems is AS/NZS 62471 which assesses all optical radiation. However, a standard called IEC TR 62778 has been specifically developed for the assessment of the blue light hazard of light sources which is called up by the generic standard above as well. It is worth noting that product-level electrical safety standard for luminaires AS/NZS 60598.1, has made it mandatory to assess the blue light hazard.

Luminaires are classified into four groups according to the photobiological risk posed by them. This risk is determined by testing to the standard IEC 62471 for UV, blue light and infrared radiation in which IEC TR 62778 is for blue light.

Photobiological risk group of luminaires

Photobiological risk group of luminaires

Notes: Blue light is measured at 200mm from the source. If RG1 is complied at 200mm, it is called RG1 unlimited.

Luminaires product marking requirement according to risk group

Do not stare at the operating light source
  • No marking for RG0, RG1 and RG1 unlimited.
  • If RG1 exceeds at 200mm, the minimum distance from the light source at which the RG1 limit is complied with, is determined by testing.
  • For portable and hand-held luminaires, when RG1 is met at > 200mm, the below symbol, meaning ‘Do not stare at the operating light source’, is marked on the product.
Due to the same reason, however for the fixed luminaires; the below should be marked on the product:
"The luminaire should be mounted so that prolonged staring at the luminaire from a distance of less than x m is unlikely."
  • RG2 luminaires will require more warnings and special consideration for their use. However, RG2 is not normally recommended according to 60598.1
  • RG3 is not allowed.

The table shows an example of optical radiation measurement in which the limit of RG0 was exceded, hence the RG1 limit was tested and passed as RG1 unlimited.