LED modules for luminaires · rated life from LM-80 data and the TM-21 6× rule, decay constant and L70, chromaticity shift, efficacy claims
An LED light module is a board or assembly carrying LED packages (SMD, COB or CSP), with or without optics and driver circuitry, mounted on a heatsink as the light source of a luminaire such as a high-bay, street light or panel. Ask three things first: what LM-80 test data, at what temperature and current, supports the life the supplier quotes, how much the colour may drift over that life, and what efficacy, colour temperature and colour rendering are measured for the complete module.
LED modules and light engines (boards with packages, optics and heatsinks) used in luminaires for general lighting and industrial lighting. Stand-alone LED drivers, complete luminaires, LED chips and displays are outside this page.
CNFX editorial research · Sources checked October 11, 2026 · 4 sources
A 2020 US Department of Energy report by RTI International on LM-80 data for white LED packages explains that LM-80 measures luminous flux maintenance, and TM-21 fits the data to Φ(t) = B·e^(−αt) to project it. Both TM-21-11 and TM-21-19 cap rated flux maintenance life at 6 times the actual LM-80 test duration, the 6X rule: a 10,000-hour test supports an L70 of at most 60,000 hours. An L70 of 50,000 hours corresponds to α = 7.13 × 10⁻⁶ and 100,000 hours to α = 3.56 × 10⁻⁶ (B = 1). [1]
Across 223 data sets, the report found 96% of α values below 6 × 10⁻⁶, corresponding to an L70 of nearly 60,000 hours, with decay depending on package type, temperature and forward current; in the report's words "the ceramic-based and COB packages tend to have the lowest α values at a given Tj", and newer polymer packages using better moulding resins approached ceramic performance at currents up to 200 mA. [1]
Editorial calculation: with B = 1 and α = 6 × 10⁻⁶ per hour, L70 = ln(1/0.7) / α ≈ 59,400 hours and L90 = ln(1/0.9) / α ≈ 17,600 hours; but if the LM-80 test ran only 6,000 hours, the 6X rule limits the rated L70 to 36,000 hours. LM-80 data are measured at stated temperatures and currents, so ask for the LED temperature and current inside your module and compare them with the test conditions. [1]
Give the supplier the luminaire type, lumen output and efficacy target, colour temperature and colour rendering, beam angle and optics, LED package type, drive current and module case temperature in your luminaire, required L70 or L90 life with LM-80 and TM-21 reports, colour-shift limit, input voltage and driver, ingress protection, size and heatsink.
02
Check colour shift and efficacy claims
The DOE report gives chromaticity shifts of Δu'v' = 0.004 and 0.007 (CS4 and CS7 lifetimes) as examples of "typical parametric failure thresholds" and evaluates the TM-35-19 projection method, which recognises incubation, recovery and emergence phases; only emergence produces shifts large enough to reach those thresholds. It found that TM-35-19 provides "reasonable and often conservative estimates of chromaticity shift magnitude" but is much less likely to give a reliable estimate of shift direction, and that projections are best when emergence has begun in the data. [1]
A module maker's listing linked to this page describes a 50 W, 90° high-bay module with SMD3030 LEDs on an aluminium heatsink at 140 lm/W. [2] Editorial calculation: 50 W × 140 lm/W = 7,000 lm if the efficacy is measured for the whole module at operating temperature; ask whether it is the LED package efficacy or the module's measured output, and at what temperature.
Efficacy depends on when it is measured. A 2023 Lodz University of Technology study of four LED road luminaires (32, 40, 75 and 100 W classes), seasoned for at least 100 h and measured for 1 h in a 2 m integrating sphere, found luminous flux fell from switch-on to thermal stabilisation by 3.52% to 9.55% while active power fell by 1.61% to 4.67%: the 75 W unit went from 7,736 lm at 80.16 W to 6,997 lm at 76.42 W, and the 100 W unit from 15,744 lm at 99.81 W to 15,028 lm at 98.20 W. The steady-state displacement power factors were 0.91 to 0.98 and current THD 8.86% to 15.85%. [4]
Editorial calculation: the 75 W luminaire's efficacy drops from 7,736 ÷ 80.16 ≈ 96.5 lm/W at switch-on to 6,997 ÷ 76.42 ≈ 91.6 lm/W once stable, and the 100 W unit from about 157.7 to 153.0 lm/W; these are complete luminaires, but the same heating applies to a module on its heatsink, so ask for module flux and efficacy measured after thermal stabilisation at the stated case temperature. [4]
03
Fix the mechanical interface so modules can be swapped
The Zhaga Consortium publishes interface specifications (Books) that let LED modules from different vendors fit the same luminaire. Its book list includes Book 3 for 50 mm diameter spot modules, Book 7 for linear and square LED modules, Book 11 for 35 mm diameter spot modules, Book 12 for COB LED arrays and holders, Book 15 for rectangular LED modules used with lens arrays and Book 19 for rectangular modules and lens plates with IP protection. [3]
Book 19 defines the keep-out volumes and mechanical attributes needed to align the module with its lenses and fit it in the luminaire. The module needs a separate LED driver and mounts on a heat sink; its maximum outline is 45 mm wide by 146.6 mm long. IP protection comes from a gasket on the heat sink around the module, pressed against the heat sink by the lens plate, so no separate protective cover is needed — Zhaga cites slimmer luminaires and higher optical efficiency as the result, and names roadway, pathway and outdoor-area lighting as the applications. Performance of the module and lens plate is deliberately left outside the specification. [3]
Editorial note: if the luminaire is to accept replacement modules later, state the Zhaga Book the module must comply with in the order, and still ask for the LM-80, TM-21 and photometric data above, because the interface specification does not cover performance. [3][1]
04
One high-power module maker for high-bay and street lighting
Shenzhen Sunshine Opto-Electronics is the company shown below; the 50 W high-bay module discussed in the efficacy section comes from its listing. [2]
The listing reviewed covers high-power LED modules for high-bay and street lighting with SMD and COB LEDs, lenses and aluminium heatsinks, alongside LED drivers. Ask for LM-80 and TM-21 reports for the LED packages used and photometric reports for the module.
05
LED packages, board, optics, lens plate, heatsink and driver
The LED package row carries the decay data; the board, heatsink and driver rows decide the temperature and current at which that data applies.
Efficacy, colour, power, life and thermal data for the quotation
Lumen target, colour and life requirement come from your luminaire. The middle column gives the DOE life rule, the Lodz warm-up results and one maker listing as examples.
Field
What it means and published values
Ask the supplier for
Luminous Flux (lm/W)
Example listing: 140 lm/W at 50 W; flux fell 3.52–9.55% to thermal stability in tested luminaires. [2][4]
1 company lists this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
How long can a supplier claim an LED module lasts?
Under TM-21, rated life cannot exceed 6 times the LM-80 test duration; 10,000 test hours support at most 60,000 hours L70. [1]
What decay rate gives 60,000 hours L70?
The DOE report links α below 6 × 10⁻⁶ per hour to an L70 of nearly 60,000 hours. [1]
How much colour shift counts as failure?
The DOE report gives Δu'v' = 0.004 and 0.007 (CS4 and CS7) as examples of "typical parametric failure thresholds". [1]
Is there a standard size for LED light modules?
Zhaga publishes interface Books; Book 19, for rectangular modules with IP-sealing lens plates, sets a maximum module outline of 45 × 146.6 mm. [3]
Should LED efficacy be measured at switch-on or when warm?
When warm: in a Lodz University of Technology study, LED luminaire flux fell 3.52–9.55% and power 1.61–4.67% during the first hour as temperatures stabilised. [4]
Sources and what still needs a direct check
Sources checked 2026-10-11. The DOE/RTI report analyses industry LM-80 data and the IES TM-21 and TM-35 methods. The Zhaga Consortium's Book 19 summary describes an industry interface specification for interchangeable modules. The module listing is a maker's own claim, quoted as an example of how efficacy is stated. The Lodz University of Technology paper (Scientific Reports, 2023, open access in PMC) measures how LED luminaire flux and power settle after switch-on.
