What Are LM-79 and LM-80 LED Testing Standards?
LM-79 and LM-80 (LED Testing Standards)
Definition: LM-79 and LM-80 are IES (Illuminating Engineering Society) testing standards that form the backbone of LED performance verification. LM-79 (IES LM-79-19) measures the total luminous flux, electrical power, efficacy (lm/W), chromaticity (CCT/CRI), and intensity distribution of a complete LED fixture at a single point in time. LM-80 (IES LM-80-20) measures the lumen depreciation of LED chips/packages over time (typically 6,000-10,000 hours) at specific temperatures, producing the data used to project L70/L80/L90 lifetimes via TM-21 extrapolation.
Technical Detail
LM-79 testing requires a goniophotometer or integrating sphere in an ISO 17025 accredited laboratory. It captures the fixture as a complete system — driver, thermal management, and optics all in place — giving the real-world performance numbers that spec sheets quote. LM-80 testing runs LED packages (not complete fixtures) at three case temperatures (typically 55, 85, and 105 degrees C) for a minimum of 6,000 hours, measuring lumen output every 1,000 hours. The data is extrapolated per IES TM-21 to project L70 (70% of initial lumens) lifetimes. A 6,000-hour LM-80 can project up to 6x the test duration (36,000 hours), while a 10,000-hour test can project up to 6x (60,000 hours).Why It Matters
Without LM-79, you cannot verify that the fixture delivers the claimed lumens, efficacy, or CCT. Without LM-80, you cannot verify the lumen maintenance claims (50,000-hour L70 is common marketing, but without LM-80 data there is no evidence). DLC and Energy Star require LM-79 + LM-80 data for listing. For B2B procurement, demand both test reports from an ISO 17025 lab — in-house testing is not acceptable for warranty-grade specifications. A fixture with LM-80 data from a NVLAP-accredited lab backing a 50,000-hour claim costs 5-10% more but eliminates the risk of 30% lumen depreciation in year 3.Typical Values: LM-79 reports: total lumens, lm/W efficacy, CCT, CRI (Ra + R1-R15), chromaticity coordinates (x,y), power factor, THD. LM-80: 6,000hr or 10,000hr data at 3 temperatures. TM-21 projection: L70 typically 36,000-100,000 hours. DLC Premium requires LM-79 + LM-80 + ISTMT.
Testing Standard: IES LM-79-19 (complete fixture photometry), IES LM-80-20 (LED package lumen maintenance), IES TM-21-21 (lifetime projection), IES LM-84 (lumen and color maintenance of LED lamps)
Verify LED fixture performance data on Compare2Best. Filter suppliers by those who provide LM-79 and LM-80 reports from ISO 17025 accredited labs. Get DLC-compliant fixtures with documented lifetime data.