ENERGY STAR® Program Guidance Regarding
LED Package, LED Array and LED Module Lumen Maintenance Performance Data Supporting Qualification of Lighting Products
NEMA Comment: Clarify what is covered by LED modules, LED Light Engine(s), remote phosphor system, rgb LED arrays, and tunable CCT? This is a fundamental question and can affect the below.
Section 1: Purpose of this Document
The purpose of this document is to provide guidance regarding lumen maintenance test reports (i.e. IES LM-80-08, or “LM-80”) for LED packages, LED arrays, and LED modules (“subcomponent(s)”) referenced to demonstrate compliance with ENERGY STAR lumen maintenance performance
requirements detailed in Program specifications for lighting products (“products”).
NEMA Comment: In parentheses the word products should be defined as lamps and luminaries. The Energy Star qualification can be done on the LED luminaires, LED lamps, and LED light engines level. Therefore, here either it needs to list all 3, or just use “products”.
The most commonly employed approach to fulfilling ENERGY STAR lumen maintenance performance requirements is through projections based upon LM-80 test reports. This guidance addresses topics related to subcomponent-level lumen maintenance data that aren’t explicitly covered in ENERGY STAR lighting specifications because of the quickly evolving nature of solid state lighting technology. The U.S. Environmental Protection Agency (EPA) will periodically review this guidance to ensure its content acknowledges the latest technological improvements to solid state lighting subcomponents.
This document supports all ENERGY STAR lighting specifications that include solid state lighting within their scope, and is intended to ensure uniform treatment of lumen maintenance data by ENERGY STAR manufacturing partners (“partners”), subcomponent manufacturers, and EPA-Recognized Laboratories and Certification Bodies.
The document addresses:
the content of LM-80 test reports (section 3)
the application of LM-80 test reports in support of product qualification (section 4) the use of existing test reports while testing of successors is underway (section 5)
Please note: this document includes guidance which may be in addition to, or in place of, the testing and reporting requirements that are detailed in IES LM-80-08.
Section 2: Definitions
ENERGY STAR program requirements for lighting products generally reference definitions provided by the Illuminating Engineering Society’s (IES) recommended practices document RP-16-10, as well as addenda as they become available. Subcomponents addressed by this guidance are LED packages, LED arrays, or LED modules.
Correlated color temperature (CCT) values in this document refer to nominal CCT values defined in ANSI C78.377-2008. Other important definitions are outlined at the beginning of each ENERGY STAR lighting specification.
Section 3: Guidance Regarding the Content of LM-80 Test Reports Submitted in Support of ENERGY STAR Qualification of Lighting Products
1. LM-80 test reports must illustrate that subcomponent lumen maintenance testing was conducted in accordance with the testing method outlined in IES LM-80-08, except as otherwise detailed in this document or in ENERGY STAR specifications.
2. LM-80 test reports must comply with the reporting requirements outlined in IES LM-80-08, except as otherwise detailed in this document or in ENERGY STAR specifications.
3. LM-80 test reports must include the subcomponent model or series number tested, and an indication of which month and year the report was first issued, and revised (if applicable).
4. LM-80 test reports must include a minimum of one close up perspective view photograph or isometric view diagram of the subcomponent, illustrating the subcomponent’s maximum overall dimensions (i.e. length, width, height) and including notation of the manufacturer-designated LED temperature measurement point (TMPLED).
5. All case temperature (Ts) subsets of the sample used to generate each LM-80 test report must be of the same correlated color temperature(s). For example, the 55°C case temperature sample subset should be composed of subcomponents of the same CCT(s) as the other two case temperature subsets.
NEMA Comment. Add the following: The CCT tolerances are the same as specified in ANSI C78.377. 6. LM-80 test reports must include a minimum of one reported case temperature (Ts). Test reports need not include three Ts values as detailed in LM-80, except as required to establish a product rated lumen maintenance life value using temperature data interpolation (see IES TM-21-11 section 6). NEMA comment: The wording “rated lumen maintenance life value” needs to be changed to “lumen maintenance projection”. TM-21-11 is only a method in which a projection of lumen maintenance can be generated and the wording describing a rating is incorrect and gives the wrong implication to the end user.
7. For LED arrays constructed as an assembly of LED dies on a printed circuit board or substrate (a.k.a. chip-on-board) with one common phosphor layer overlaying all dies:
One LM-80 test report may represent a range of LED array sizes (i.e. number of LED dies) if all of the following are satisfied:
NEMA Comment: This section was a large portion of discussion and final consensus was not reached. Further discussions are needed to verify the technical content and the methods needed to measure technical items. At a very high level, the overall discussion focused on the defining of the LED array through items “a through e”, which was thought insufficient and in some cases technically incorrect.
a. The report details the smallest LED array size (i.e. model number with the fewest number of dies) and the largest LED array size (i.e. model number with the greatest number of dies) for which the report is applicable, which may be accomplished by detailing all model numbers covered by the report; and,
NEMA Comment: The characteristics that predominantly affect lumen maintenance and that could define, or bracket “similar” arrays and or product families aretotal power, power density of the die (W/mm^2), worse case temp within the array, and average thermal resistance. The proper
procedures to measure these characteristics are not currently defined. Tests need to be developed. NEMA is happy to assist in this.
Consensus was not reached on this topic but the majority of NEMA members had issues with using the number of dies within an array as one method of the LM-80
b. LM-80 testing has been conducted on the smallest and largest LED array sizes,
demonstrating both sizes meet ENERGY STAR requirements. For this testing each of the following must be held constant across all sample sets:
NEMA Comment: LM-80 style testing does not need to be done on the smallest and largest array, rather the worse-case items shown in a. The testing of the smallest and largest array can be very costly and in the end not truly bracket or define lumen maintenance for array families. Product Series number are truly ones used for marketing reasons and such do not need to be included in the overall LM-80 reports. The proper procedures to measure these characteristics are not currently defined, tests need to be developed. NEMA is happy to assist in this.
i. Product series / base model numbers for small and large LED array samples ii. Selected elevated case temperature(s) (Ts)
iii. Correlated color temperature bins (warm white bins recommended to provide greatest flexibility; see section 4, item 4)
iv. Wiring configuration: half of each case temperature (Ts) sample set wired with all dies in series, half with dies wired in a series/parallel configuration
NEMA Comment: The actual configuration of the LED die is not a factor in Lumen maintenance and it should not be mandatory to test different configurations. The average LED drive current, power density and thermal resistance are the true measure of an array. As long as these characteristics are defined and followed, an array that has all the led die in series will not act different than an LED die arranged in series parallel. The orientation of the LEDs can be changed due to customer
requirements for performance items like electrical efficiency. The LED array manufacturer should have the ability to organize the LED die in any manner as long as items like drive current, power density and thermal resistance do not change. This is needed for the constant increase in efficiency in LED die.
Also LM-80 testing has already begun for a lot of array companies and the above testing is unnecessary and can actual slow down the industry from introducing better products in the field faster.
v. Forward drive current: samples operated at rated drive current per subcomponent product literature
NEMA Comment: To clarify, the rated drive current can be higher than the actual drive currents shown in LM-80 testing. The manufacturer should have the ability to rate the drive current to the level that is needed based on customer specifications. The word rated is a manufacturer-specific term and does not refer back to the LM-80 test report in all cases.
vi. Luminous flux binning: middle flux bin within each LED array size; and,
NEMA Comment: This is not practical and adds no value to lumen maintenance testing. The flux bin is not needed since the LM-80 is average of a sample set and normalized to 100% for simplicity.
c. The reported lumen maintenance data is that of the tested LED array size, smallest or largest, with the lower lumen maintenance; and,
d. The current-per-die is reported; and,
NEMA Comment: The value for current per die is calculated and is not cannot be measured accurately in practice.
e. The smallest and largest LED array reports are made available upon request.
NEMA Comment: This item should be removed. The above defines the overall product family and keeping separate reports would all be contained in one report.
8. For LED arrays constructed as an assembly of LED packages on a printed circuit board, each with their own phosphor layer:
LM-80 test reports must be presented either:
for the individual LED packages incorporated into the array or, for the entire LED array, with current-per-LED package reported.
Refer to NEMA comments in section 4.4 for additional information. This section can be heavily impacted depending on whether or remote phosphor, RGB LED, or tunable CCT arrays are included.
Section 4: Guidance Regarding the Application of LM-80 Test Reports in Support of ENERGY STAR Qualification of Lighting Products
1. A minimum of one reported case temperature (Ts) greater than or equal to the in situ measured TMPLED value must be included in the LM-80 test report for the employed subcomponent(s).
2. Partners may not claim on the product, product packaging or product literature, either printed or electronic, longer rated lumen maintenance life values than those established by the IES TM-21-11 projection method.
NEMA Comment: The word “established” should be replaced with “estimated”. TM-21 is a projection and does not ensure real lumen maintenance life values.
3. The subcomponent make(s) and model number(s) used in the product to be qualified must be reported, detailing the complete nomenclature(s) required by the subcomponent manufacturer(s) to sell the subcomponents.
NEMA Comment: The complete nomenclature from most LED manufacturers contains VF, intensity, color bins. In keeping with that, LM-80 is focused on lumen maintenance the only real key factor is CCT and therefore the nomenclature does not have to include items like VF, intensity, etc.
4. The correlated color temperature(s) of the LM-80 sample set may differ from the product as follows:
LM-80 test reports for warm white (2700K, 3000K and 3500K) samples may be referenced to support qualification of a product of any nominal CCT allowed in ENERGY STAR specifications.
LM-80 test reports for cool white (4000K, 4500K, 5000K, 5700K and 6500K) samples may be referenced to support qualification of a product of any nominal CCT 4000K or higher allowed in ENERGY STAR specifications.
NEMA Comment : The CCT should be defined as the following grouping (2700K, or 3000K, or 3500K) and (4000K, or 4500K, or 5000K, or 5700K, or 6500K). The wording “may be referenced” should be changed to “used to qualify”. “Nominal CCT” should be defined as “nominal CCT as defined in ANSI C78.377”
This section is in conflict with the current Energy Star Luminaires specification.
5. The drive current value reported in an LM-80 test report referenced to support qualification of a product must be greater than or equal to the subcomponent drive current employed in the product.
6. Qualification of a product employing both phosphor-converted white and single-color LED packages must demonstrate compliance with lumen maintenance requirements by referencing an LM-80 test report for a sample of LED arrays incorporating both types of LED packages.
NEMA Comment: This is in violation of today’s understanding of qualifying LEDs on PCB’s. Today the
array manufacturer will submit only LM-80 data on the LED used in the array. Using different colors should have no impact. Separate LM-80 test reports for each “color” should be allowed.
7. For LED arrays constructed as an assembly of LED dies on a printed circuit board or substrate (a.k.a. chip-on-board) with one common phosphor layer overlaying all dies:
One LM-80 test report representing the performance of a range of LED array sizes may be presented to support product qualification, if all of the following are satisfied:
b The LED array size used in the product is within the tested array size range (see section 3, item 7); and,
c The report is for the same LED array product series / base model number; and,
d The current-per-die in the product is less than or equal to the current-per-die employed in LM-80 testing.
NEMA Comment: This is a repeat, section 3.7, and so items b, c, and d should be deleted
8. For LED arrays constructed as an assembly of LED packages on a printed circuit board, each with their own phosphor layer, the in situ TMPLED temperature of the hottest package in the array shall be used for lumen maintenance projection purposes.
Section 5: Guidance Regarding Subcomponents Presented to EPA-Recognized Certification Bodies as Successors to Previously Tested Subcomponents
1. Definition: an LED package, LED array or LED module may be considered a “successor” to another subcomponent if photometric performance (i.e. lumen maintenance and luminous flux) is greater than or equal to the performance detailed in the referenced original LM-80 test report, and is primarily attributable to improvements in internal quantum efficiency, phosphor or thermal
management. In addition, relative to the referenced original subcomponent, a successor features: a) a unique model number; and,
b) the same number of LED dies; and,
c) the same dimensions of the LED die(s); and,
d) the same materials in the optical path after exiting epitaxial structures; and, e) the same deposition processes employed; and,
f) the same tested case temperature (Ts) values; and, g) the same nominal CCT; and,
h) equal or smaller overall dimensions which would affect fit; and, i) equal or lower thermal resistance of the subcomponent; and, j) equal or lower rated maximum recommended drive current; and, k) equal or lower per-chip current density (e.g. mA/mm2)
NEMA Comment: This section is difficult to understand and really doesn’t add any value since any change to the above facilitates a new test. The overall gains in internal quantum efficiency, phosphor or thermal management can only be achieved by changing items “a” through “k. For instance item “e” does not allow for any process improvements that normally happen as the wafers are
manufactured over time to increase yield. The below is a better grouping that allows for better definition of successor:
a) a unique model number;
b) equal or lower - power density per-die (e.g. w/mm2)
c) the same materials in the optical path after exiting epitaxial structures; and, d) the same or lower tested case temperature (Ts) values; and
e) the same or greater nominal CCT; and
f) equal or lower drive current within LM-80 test space; and g) equal or lower thermal resistance.
The contents of this section are dependent on discussions and decisions regarding NEMA comments on power density and how it should be addressed.
2. Application: a partner may present a product for qualification using a subcomponent considered a successor by the subcomponent manufacturer if each of the following are satisfied:
a) The subcomponent meets the above successor definition; and,
b) A complete LM-80 test report is provided for the referenced original subcomponent; and, c) ENERGY STAR lumen maintenance and color maintenance performance requirements would be
satisfied using the referenced original; and,
d) A minimum of 3,000 hours of LM-80 testing data (compliant with LM-80 and guidance in this document) is submitted for the successor subcomponent; and,
e) That data demonstrate lumen maintenance, color maintenance and luminous flux greater than or equal to the original subcomponent at 3,000 hours; and,
f) Partner provides a date, not to exceed 170 days from the 3,000 hour date, when the successor subcomponent’s complete (i.e. final, 6,000 hour) LM-80 test report will be available from the subcomponent manufacturer; and,
g) Partner agrees to provide the complete LM-80 test report for the successor subcomponent as soon as it is available.
NEMA Comment: If the LED (package, array or module) meets the criteria set forth in #1 Section 5, then no re-testing per LM-80 is needed. If an LED (package, array or module) does not fit #1 then it should be allowed to apply for Energy Star as long as: 1) LM-80 testing is started, 2) the LED (package, array or module) has made it to 3,000 hours, and 3) it achieves the correct Energy Star levels for lumen
maintenance. Its use in LED products covered by Energy star should be approved with the caveat that if it fails to meet the Energy Star levels at 6000 hours the product can be disqualified.
Discussion is called for in regards to measurement and reporting tolerances for LM-80 in with respect to pass/fail criteria.
3. Certification of products employing successor subcomponents may be withdrawn if the final 6,000 hour successor LM-80 test report is not provided in a timely manner, or if the test report does not demonstrate equal or improved performance relative to the referenced original LM-80 test report.
NEMA Comment: Clause 8.3 should be changed to read “Certification may be withdrawn if the criteria of clause 5.2 are not met.”
