Tech tips Tech tips by product PIXA-3R Information on LED lighting

Information on LED lighting

As a headlamp manufacturer concerned for the safety of its customers, Petzl has chosen to present information in its product instructions about the risks to the eyes associated with LED lighting. For this, the company uses the EN 62471: 2008 standard, photobiological safety of lamps and devices using lamps, though it is not mandatory. This standard classifies lamps according to risk groups.

LED lighting and blue light

Most of today's headlamps are made with LEDs (Light Emitting Diodes). Currently, the most profitable way to make white LEDs is to combine a blue-wavelength diode with a yellow luminophore.

As seen in the diagram below, LEDs emit primarily blue light (wavelength 450-495 nm).

Emission spectrum of a Petzl headlamp

In case of direct, repeated exposure at high power, blue light can harm the eyes: retinal damage, aggravation of macular degeneration, blinding. These risks are especially significant for children because of their higher sensitivity to blue light.

This is why as a headlamp manufacturer, Petzl has a duty to inform its customers of the existence of these risks, even if they are minimal for normal use of Petzl headlamps.

Risk groups

The EN 62471: 2008 standard on the photobiological safety of lamps provides a methodology for measuring and classifying the risks due to blue light emission.

The risk groups are as follows:

Risk group 0: no risk.
Risk group 1: low risk. The product presents no risk related to exposure limits under normal usage conditions.
Risk group 2: moderate risk. The reflex to look away from the lamp suffices to reduce the risk.
Risk group 3: high risk. The product can present a risk even with a momentary or short exposure.

Depending on the risk group. the manufacturer must make a label and/or a specific informational notice.

It is important to underline that the risk level is partly related to the distance between the light source and the eye. Thus, moving away from the light source reduces the risk level. The risk level is also related to the duration of exposure.

Brightness and beam shape are other factors influencing the risk level. Note that Petzl determines the risk level of its lamps by testing the worst-case scenario: a focused beam at maximum brightness.

Moreover, the risk group is currently evaluated at 20 cm from the lamp, which is relatively close compared to a common accidental exposure.

How does Petzl communicate in its instructions?

Here is an example of an informational insert on photobiological risk given in the Instructions for Use for Petzl headlamps:

Petzl communicates about the maximum risk associated with its lamps, specifying the distances at which this risk level is reduced. For this example, the lamp is classified in risk group 2. The lamp moves to risk group 1 when it is at a distance of 1.3 m from the user's eyes.

You should know that most headlamps currently on the market are classified in a risk group greater than or equal to 1. However, few manufacturers communicate about this risk.