Projecting Long Term Lumen Maintenance of LED Light Sources

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LED light sources provide a very long usable life but light output gradually depreciates over time. TM-21-11 provides the method for determining when the “useful lifetime” of an LED is reached, a point when the light emitted from an LED depreciates to a level where it is no longer considered adequate for a specific application.

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SKU: TM-21-11 Category:

Description

This document recommends a method for projecting the lumen maintenance of LED light sources from the data obtained by the procedures found in IES document LM-80-08 Approved Method for Measuring Lumen Maintenance of LED Light Sources.

LED light sources provide a very long usable life but light output gradually depreciates over time. TM-21-11 provides the method for determining when the “useful lifetime” of an LED is reached, a point when the light emitted from an LED depreciates to a level where it is no longer considered adequate for a specific application. Lumen maintenance of LEDs can vary from manufacturer to manufacturer and between different LED package types produced by a single manufacturer.

Softcoveror Digital PDF: 25 pages
Publisher: Illuminating Engineering Society (2011)
SKU: TM-21-11
ISBN-13: 978-0-87995-259-4
Dimensions: 8½” x 11″

Additional information

Weight 1 lbs
Dimensions 11 x 8.5 x .25 in
Format

Digital, Softcover

Addendum

Addendum A for TM-21-11: Projecting Long Term Lumen Maintenance of LED Packages [PDF 302KB]

Addendum B for TM-21-11: Projecting Long Term Lumen Maintenance of LED Light Sources [PDF 192KB]

Table of Contents

  • Introduction
  • Scope
  • Normative References
  • Definitions
  • Test Data and Sample Size
  • Lumen Maintenance Life Projection
  • Temperature Data Interpolation
  • Report
  • Annex A Rationale for the Recommended Data Extrapolation
  • Annex B Sample Size Selection for Data Extrapolation
  • Annex C Least Squares Formula
  • Annex D Limit for Duration of Prediction
  • Annex E Data Test Set for Validation of Calculation – Examples
  • Annex F Consideration of Manufacturer’s Prediction Model
  • Annex G Analysis of Mathematical Modeling as a Method of Projecting Lumen Maintenance Life
  • Informative References