Petzl uses a rigorous and clearly defined protocol to evaluate the performance of our headlamps.
The measurements are taken in the lab and are reliable, precise performance indicators.
Results obtained in this way allow us to compare the lighting performance of many different headlamps. Consequently, it is much simpler for users to choose a product for their specific needs based on their own criteria. The tests are carried out with five headlamps and two sets of standard or rechargeable batteries identical to the ones sold with the headlamp (for headlamps sold without batteries, quality alkaline batteries are used). The published results represent the average of 10 measurements.

Minimal lighting

Before measuring lighting distance and burn time, it’s useful to have a definition of minimum lighting, below which a headlamp is no longer effective, i.e., when the light no longer provides satisfactory visibility. Petzl has evaluated this illumination level to be equivalent to the light emitted from a full moon on a clear night, or 0.25 lux.
This minimum lighting level is used as a reference for measuring lighting distance and duration.

Influence of temperature on measurements

The ambient temperature influences the performance of both standard and rechargeable batteries. In order to maintain a stable testing environment and comparable results, all measurements are performed at 20 °C.

 

Lumens

A lumen (lm) is a unit of measurement for the total quantity of light emitted (luminous flux).
The luminous flux is the total quantity of light emitted in every direction from a source of light. Luminous flux is measured in the lab, with the help of an integrated sphere device.
This measurement is complementary to the lighting distance. Two light sources positioned at the same distance can in fact shine with different intensities. As with lighting distance, luminous flux diminishes as the energy source drains.
Petzl indicates the total luminous flux, thus providing the user with the maximum possible output of each light.