What is IEC 62471?

Assess light safety through wavelength and exposure conditions

IEC 62471 is a standard used to assess the photobiological hazards to eyes and skin from optical radiation emitted by lamps and lamp systems. The base standard, IEC 62471:2006, addresses electrically powered, non-laser sources over 200–3000 nm, including LEDs. For lighting products, the question is more than whether a source looks very bright. Wavelength, radiation level, viewing geometry and exposure duration must be considered together.

Editor's note: A risk group is not a safety label independent of the measurement conditions. A report based on a 20 cm distance does not establish that prolonged viewing from 5 cm is safe. Likewise, RG0 does not mean unrestricted safety at every distance and in every use. Read the distance, operating settings and assessed hazards stated in the report.

Why assess UV, visible light and infrared separately?

Ultraviolet radiation can create photochemical hazards to the eyes and skin. The blue light hazard in the visible region is a retinal hazard assessed using appropriate spectral weighting. For infrared radiation, thermal effects become important according to wavelength and exposure. The hazard from invisible radiation cannot be inferred from how bright a source appears. In particular, the absence of glare from a UV source does not remove the need for protection.

What do RG0, RG1, RG2 and RG3 mean?

RG0 / Exempt group: Sources meeting the standard's exempt-group criteria under the specified assessment conditions.

RG1 / Low risk: Sources not expected to present a hazard under normal behavioural limitations. This is not permission to stare deliberately into the source.

RG2 / Moderate risk: The assessment takes account of exposure being limited by aversion to bright light or thermal discomfort. Work requiring prolonged, close viewing should not rely on that response.

RG3 / High risk: Sources for which even brief exposure can present a photobiological hazard. Measures to restrict access and exposure are needed.

These four groups summarise the base 2006 approach. Product-specific parts can introduce additional assessment and marking requirements. RG2 does not mean that every brief glance inevitably causes injury, and RG3 does not establish immediate injury under every possible condition.

Why are watts, lumens, lux and kelvins insufficient?

Watts and lumens distinguish electrical consumption from visually weighted light output; they do not establish a photobiological risk group on their own. A lux measurement does not replace assessment of UV or IR hazards. Colour temperature in kelvins describes colour appearance, while CRI describes colour rendering. Two products with the same colour temperature can have different spectra, optics and accessible radiation.

Assessment uses spectral measurements and weighting functions for the relevant hazard. Quantities include irradiance (W/m²), describing optical power arriving at a surface, and radiance (W/(m²·sr)), describing directional emission from the source. Measurement distance, field of view and apparent source size influence the result. A photodiode can detect light, but a reading from a single detector is not a complete conformity assessment without the appropriate optical setup and calibration.

Which specialised part applies to which product?

IEC 62471-5:2015 addresses risk classification, measurement conditions and associated product requirements for image projectors. IEC 62471-6:2022 addresses lamp products whose primary purpose is UV emission, including UV LED products. IEC 62471-7:2023 concerns electrical light sources and luminaires emitting mainly visible radiation for illumination or signalling.

The IEC catalogue copy of Part 7 incorporates the 2023 and 2024 corrigenda and the 2025 interpretation sheet. Check the applicable part, edition and corrections rather than looking only for “62471” on a report. The assessment methods for different product families should not be reduced to a single generic table.

Keep laser product safety distinct

The base IEC 62471 standard excludes laser sources. The principal laser safety framework is IEC 60825, particularly IEC 60825-1. The laser class of a laser sensor is not the same classification as an LED source's risk group. For certain laser-illuminated display products, accessible output and the relevant product provisions require separate consideration; information about a laser module does not replace assessment of the complete product.

What changes in industrial applications?

LED and machine vision lighting: Lenses, reflectors, diffusers and drive current can change accessible radiation. A component report for an SMD or COB LED does not automatically establish conformity of a final system with different optics. Define the power supply and driver settings, dimming arrangement, pulsed operation and highest output options in the assessment.

UV processing enclosure: In UV curing and similar equipment, the priority is to limit radiation reaching the user through an enclosure and suitable safeguards. Interlocking that prevents exposure when a cover opens, appropriate optical windows and safe maintenance arrangements must be considered for the application. An ordinary transparent cover should not be assumed to provide the required UV protection.

Optical sensors: A photoelectric sensor, through-beam sensor or fibre-optic system may use a visible LED, IR LED or laser source. Choose the assessment framework from the actual source and accessible output, not the product name. Close viewing during adjustment can create an exposure different from normal production use.

What does a photobiological report not establish by itself?

LED flicker, glare and effects of light on sleep timing are different concepts from the blue light hazard defined for the retina. An IEC 62471 result should not be presented as approval of every aspect of lighting and health. Likewise, an enclosure's IP protection rating does not indicate its optical safety classification.

Electrical shock, fire and driver safety require the relevant product standards as well. Examples include IEC 61347 for lighting controlgear and IEC 62368 for audio/video and information technology equipment within its scope. Photobiological conformity alone does not establish that every product safety requirement has been met.

How should you assess a test report?

The product model and optical configuration, source, operating current, measurement distance, continuous or pulsed operation, assessed hazards and required user information should be traceable in the report. For laboratories working under ISO/IEC 17025, check whether the relevant measurement falls within their accredited scope. A certificate cover or component approval alone is insufficient evidence.

Assess source enclosure, restricted access, suitable optical filtering and the operating instructions together. Where personal protective equipment is needed, select it for the wavelength and exposure involved. When the product or optical configuration changes, review whether the previous report still covers the new arrangement.