Approved Method: Projecting Long-Term Luminous Flux Maintenance of LED Lamps and Luminaires

Projecting Long-Term Luminous Flux Maintenance of LED Lamps and Luminaires

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ANSI/IES TM-28-20
Document Type: Technical Memorandum (TM)

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SKU: ANSI/IES TM-28-20 Category: Tag:

Product Description

Approved American National StandardThis document provides guidance and recommended procedures for sampling, test intervals and duration, and a method for long-term luminous flux maintenance projection for LED lamps and luminaires. The intent is to help product manufacturers and users, standards developing bodies, and other organizations to avoid any unnecessary burdens related to excessive product testing. A balance was sought between testing time and effort on one side, and sufficient statistical rigor on the other. A direct and a combined method for luminous flux maintenance projection are proposed; the latter allows the use of luminous flux maintenance data obtained for both the lamp or luminaire being tested as well as the LED sources used in it.

Page count: 15 pages
Publisher: Illuminating Engineering Society (2020)
SKU: ANSI/IES TM-28-20
ISBN-13: 978-0-87995-390-4

Chapters:

  • 1.0 Introduction and Scope
    2.0 Normative References
    3.0 Definitions
    4.0 Samples and Test Data
    5.0 Luminous Flux Maintenance Projection
    6.0 Report

Citation Format:
Illuminating Engineering Society. ANSI/IES TM-28-20, Approved Method: Projecting Long-Term Luminous Flux Maintenance of LED Lamps and Luminaires. New York: IES; 2020.

CONTENTS

  • 1.0 Introduction and Scope
  • 1.1 Introduction
  • 1.2 Scope
  • 2.0 Normative References
  • 2.1 ANSI/IES LM-80-20
  • 2.2 ANSI/IES TM-21-19
  • 2.3 ANSI/IES LM-84-20
  • 3.0 Definitions
  • 3.1 device under test (DUT)
  • 3.2 sample set
  • 4.0 Samples and Test Data
  • 4.1 Samples
    4.1.1 Sampling Selection Recommendations
    4.1.2 Sampling Size Recommendations
  • 4.2 Data to be Used
    4.2.1 Data for Direct Extrapolation
    4.2.2 Data for Combined Extrapolation
  • 5.0 Luminous Flux Maintenance Projection
  • 5.1 Procedures for Projection Method 1, Direct Extrapolation of LM-84 Data
    5.1.1 Normalization
    5.1.2 Average
    5.1.3 Data Used for Curve-Fit
    5.1.4 Curve-Fit
    5.1.5 Adjustment of Results
    5.1.6 Notation for Luminous Flux Maintenance Life
    5.1.7 Ambient Temperature Data Interpolation for Direct Extrapolation
    5.1.7.1 Select Case Temperature Ts
    5.1.7.2 Convert All Temperatures to Kelvins
    5.1.7.3 Use the Arrhenius Equation to Calculate the Interpolated Luminous Flux Maintenance Life
    5.1.7.4 Applicability of the Arrhenius Equation
    5.1.7.5 Limit for Extrapolation
  • 5.2 Procedures for Projection Method 2, Combined Extrapolation of LM-84 Data and LM-80 Data
    5.2.1 Normalization
    5.2.2 Average
    5.2.3 Selection of the LM-80 Data Set
    5.2.4 Curve-Fit of the LM-80 Data Set
    5.2.5 Calculation of the Δα Value
    5.2.6 Projection
    5.2.7 Adjustment of Results
    5.2.8 Notation for Luminous Flux Maintenance Life
  • 6.0 Report
  • Annex A – Determination of LED Forward Current in the Combined Extrapolation Method
  • Annex B – Derivation of the Formulas Used for Combined Extrapolation Method
  • Annex C – Example of the Combined Extrapolation Method
  • Annex D – Statistical Modeling

ARTICLES