LM-79 and LM-80: LED Testing Standards

Why Do LED Testing Standards Matter?

As LED technology continues to advance, standardized testing methods like LM-79 and LM-80 have become indispensable in the lighting industry. These standards offer consistent guidelines for evaluating the performance, efficiency, and durability of LED lighting products, and they play an essential role in meeting regulatory requirements and industry expectations. Testing standards help manufacturers benchmark their products against market expectations, and for consumers, they instill confidence that the LED lighting products they purchase will meet performance claims and energy efficiency goals.

Moreover, these standards serve a dual purpose by supporting both regulatory compliance and industry quality control. Government and regulatory agencies often base energy-efficiency certifications, such as Energy Star, on compliance with LM-79 and LM-80, making these standards a gateway to certification and qualification for rebates and incentives. These testing methods are also vital for designers and specifiers who select LED products for projects with specific performance criteria, as the data from LM-79 and LM-80 enables reliable comparisons and helps them select products that meet exacting requirements.

Without such standards, it would be difficult for consumers and professionals alike to distinguish between high-quality and low-quality products in the market. The importance of standardized testing is even more pronounced given the rapid evolution of LED technology, which requires updated testing methodologies that can keep up with new performance benchmarks.

What is LM-79?

The LM-79 standard, formally titled "Electrical and Photometric Measurements of Solid-State Lighting Products," was developed by the Illuminating Engineering Society (IES) to establish procedures for evaluating the performance of LED luminaires and lamps. It provides a standardized approach to measure LEDs’ electrical and photometric properties, enabling reliable comparisons of performance metrics across different products and manufacturers. This standard is particularly critical because LED products are more complex than traditional lighting, requiring unique methods to accurately assess aspects such as color consistency, brightness, and overall efficiency.

LM-79 testing involves a controlled lab environment with specific parameters for evaluating light output, luminous efficacy (lumens per watt), power consumption, chromaticity, and correlated color temperature (CCT). The standard also addresses the need to assess color rendering index (CRI), which measures a light source's ability to accurately reveal the colors of objects. These measurements are performed using specialized equipment such as integrating spheres and goniophotometers, which help determine the total luminous flux and light distribution patterns.

Importance of LM-79 in the Industry

The LM-79 standard is fundamental to the lighting industry as it provides transparency and comparability, allowing consumers and professionals to make informed choices between LED products. Manufacturers use LM-79 data to back up performance claims and to meet the requirements for certifications and incentives, such as the Energy Star label, which relies on LM-79 testing for qualification. By adhering to LM-79, manufacturers demonstrate that their products are capable of delivering the stated performance in terms of brightness, color quality, and efficiency, which enhances consumer confidence.

For consumers, designers, and lighting professionals, LM-79 certification serves as a quality assurance mechanism, confirming that an LED product can meet or exceed certain performance benchmarks. It is also used to verify compliance with government regulations and energy efficiency programs, which often include rebates or incentives for certified products. Additionally, in professional settings such as commercial buildings, hospitality venues, and public spaces, lighting designers rely on LM-79 data to ensure that the selected LEDs meet specific performance requirements, contributing to the overall aesthetic and functional goals of their projects.

What is LM-80?

LM-80, formally titled "Measuring Lumen Maintenance of LED Light Sources," focuses on assessing the long-term performance and durability of LED packages, modules, and arrays. Unlike LM-79, which evaluates immediate photometric and electrical characteristics, LM-80 measures the decline in light output over time, also known as lumen depreciation. Lumen maintenance, as measured by LM-80, is a critical factor in predicting an LED's lifespan, which is often one of the primary advantages promoted by manufacturers.

LM-80 testing typically involves exposing LED components to different stress conditions—such as elevated temperatures—to assess their performance under prolonged use. The standard requires manufacturers to test LEDs for at least 6,000 hours, though many conduct tests for up to 10,000 hours to provide more reliable data. The results are then used to predict the LED’s lifetime based on the rate of lumen depreciation observed during the testing period. This information is instrumental for end-users looking to invest in LEDs with extended longevity, as it allows them to select products that will maintain high light output and performance over time.

Importance of LM-80 in LED Product Development

LM-80 plays an essential role in LED product development and the overall quality assurance process. For manufacturers, the lumen maintenance data collected through LM-80 testing helps to refine designs, materials, and production methods to enhance product durability and longevity. By understanding how their products perform over long periods, manufacturers can make adjustments to improve reliability, which is crucial for consumer satisfaction and market reputation.

Furthermore, LM-80 data helps manufacturers substantiate marketing claims regarding lifespan and lumen maintenance, fostering transparency and building consumer trust in LED products. For example, many LED products advertise a projected lifetime of 25,000 to 50,000 hours, and this prediction is often based on LM-80 testing and the calculated rate of lumen depreciation. This level of transparency in marketing builds confidence among consumers, as they know that the lifespan claims are backed by rigorous testing.