LM 79

LM-79 is an IES (Illuminating Engineering Society) approved testing standard that defines the procedures for measuring the photometric and electrical characteristics of solid-state lighting (SSL) products, such as LED luminaires and integrated LED lamps. It is one of the foundational documents for qualifying LED products for energy efficiency programs, performance labeling, and regulatory compliance.

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Key Characteristics Measured in LM-79 Testing:

Luminous Flux (Total Light Output)

Measured in lumens (lm).
Represents the total amount of visible light emitted by the luminaire in all directions.

Purpose of LM-79:

The main objective of LM-79 is to provide a standardized method for evaluating LED lighting products. This allows for consistent and accurate comparison of performance data, including metrics like:

Luminous flux (total light output)
Luminous efficacy (lumens per watt)
Input power (watts)
Color characteristics (CCT, CRI, Duv)
Light intensity distribution
Power factor
THD (Total Harmonic Distortion)

Key Requirements:

LM-79 testing must be conducted by accredited laboratories (such as NVLAP-accredited).
It is intended only for complete LED products — not for individual components like LED chips or drivers.
The tests are absolute photometry (as opposed to relative), meaning the entire fixture or lamp is tested as a whole.
The product must reach thermal equilibrium before testing begins.