Forum for Illumination Research, Engineering, and Science (FIRES)

Standards Category: Measurements and Calculations
An Intuitive Metric for Lumen Maintenance

An Intuitive Metric for Lumen Maintenance

By Eric Bretschneider

For better or for worse, the lighting industry commonly associates the lifetime of LEDs and LED-based lighting products with L70 – the amount of time for the lumen maintenance of an LED-based device to reach 70% of its initial value. Admittedly, the failure of other components, particularly those that provide power to LEDs, are more likely to determine the overall lifetime of an LED-based component or luminaire. However, only lumen maintenance is considered here. Read More

The Lighting Design Objectives (LiDOs) Procedure

By Christopher Cuttle, MA, PhD, FCIBSE, FIESANZ, FIESNA, FSLL

This procedure is based on the concept that there is real advantage to be gained from changing the illumination metrics used for specifying, measuring and predicting lighting applications so that they relate to people’s responses to visible effects of lighting in indoor applications. Read More