The Illuminating Engineering Society (IES) has published three new reference documents regarding various performance aspects of LEDs.
The first document is a technical memo: TM-28-14: Projecting Long-Term Luminous Flux Maintenance of LED Lamps and Luminaires.
TM-28-14 is meant to serve as a guide and overview for “sampling, test intervals and duration, and a method for long term luminous flux maintenance projection for LED lamps and luminaires using data obtained when [a] product is tested according to IES LM-84: Approved Method for Measuring Luminous Flux and Color Maintenance of LED Lamps, Light Engines, and Luminaires and LM-80: Approved Method: Measuring Lumen Maintenance of LED Light Sources. According to Rita Harrold, IES Director of Technology, “This standard [ TM-28-14] is meant to help both manufacturers, and users, and standards developing bodies to avoid burdens related to excessive testing by balancing testing time effort and statistical rigor.”
In addition to this guide, the IES has also published two new testing procedures for LEDs: LM-84-14: IES Approved Method for Measuring Luminous Flux and Color Maintenance of LED Lamps, Light Engines, and Luminaires, and LM-85-14: Approved Method for Electrical & Photometric Measurements of High Power LEDs. These documents help to establish the emerging body of standard and uniform laboratory testing procedures for solid-state light sources. LM-84-14 addresses lumen decay and color shift, while LM-85-14 addresses the optical performance of LEDs at higher power levels, which require higher operating temperatures.
All of the documents are available for purchase--in print or as PDF downloads--online from the IES store.