IES publishes life estimation method for Outdoor Led Lights and luminaires IES TM-28-14

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Overview:
In May 2014, IES released a method for calculating the life of outdoor led lighting products, namely bulbs and lamps. This method borrows from IES TM-21
The successful experience in the application has corrected the errors caused by the application of TM-21 in the finished product. IES has been a certification body for lighting products in North America
One of the important standard sources of the ENERGY STAR® program, DesignlightsTM program, and LED Lighting
Facts® plan and other references. Especially if the EPA considers the IES life expectancy method to be reasonable and feasible, the ENERGY STAR® calculation
The aging requirements for bulbs may change accordingly. How does this affect manufacturers?
Standard content:
1. The standard is applicable to Outdoor LED lighting products. Not applicable to LED packages, arrays, and modules. So there is no conflict with IES TM-21.
2. The life expectancy is based on the aging test data (or report) of IES LM-84-14 standard products. If you use the combination method to calculate, you still need
The light source must have the test report of IES LM-80-08 that has been tested. It should be noted that IES LM-84 has not yet been officially adopted by the EPA.
Accepted as the test method of the Energy Star Program. If adopted by the EPA, LM-84 and TM-28 may work at the same time.
3. The standard introduces two life estimation methods, a direct inference method and a combined inference algorithm. You can choose one of the two methods, each in different
Applicable under circumstances and conditions.
IES claims that the purpose of the standard is to reduce the test burden by reducing the test cycle (the meaning of the extrapolation). Then if the
Does the standard reduce the test burden of manufacturers as IES said? We will use the existing ENERGY STAR bulb aging requirements

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(ENERGY STAR Lamp V1.1) for comparison. The following briefly introduces two calculation methods:

Direct push method:
1. It is required to provide LM-84 reports of bulbs and lamps. The test cycle is 6000 hours, and the test interval should not exceed 1000 hours.
2. The derivation formula is the same as TM-21. The temperature insertion method can also be used (then LM-84 is required to be done at multiple temperatures).
3. No LM-80 report is required.
4. The requirements for the number of samples and the upper limit of the estimated period are as follows, and the coefficient x is a multiple of the total test period that can be estimated.

For example, if 3 samples are tested for 6000 hours, the estimated upper limit is 18000 hours.
If you compare the lamp standard requirements of ENERGY STAR®: without LM-80 report, the lamp only needs to be tested for 0 hours
And 6000 hours of aging time (life upgrade is calculated separately, the test cycle is 1/4 of the declared life). Then the required test interval for TM-28
It is 1000 hours, which increases the test time point, but if it is estimated that 4 times the test period, only 4 samples are needed, which is less than ENERGY STAR
The number of samples.

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Combination push algorithm
1. LM-84 reports of bulbs and lamps are required to be provided. The test cycle is 3000 hours, and the test interval should not exceed 500 hours.
2. The light source must refer to IES LM-80 to complete the 6000-hour test.
3. The derivation is based on the IES LM-84 test report, and on this basis, the 6000-hour LM-80 report is used to correct the attenuation rate to obtain a positive
Accurate LM-84 decay rate curve.

4. The requirements for the number of samples and the upper limit of the estimated period are as follows, and the coefficient x is a multiple of the total period of IES LM-84 that can be estimated. .

For example, if 10 samples are tested for 3000 hours, the upper limit of the estimated period shall not exceed 12000 hours.
If you compare the lamp standard requirements of ENERGY STAR®: with the LM-80 report, the china led outdoor lamp only needs to be tested for 0 hours
And 3000 hours, it can be estimated to 25000 hours. If calculated according to LM-84, even if 15 samples are used, after 3000 hours
It can only be estimated to 18,000 hours, which can barely meet the minimum life requirements of decorative lights. To meet the 25,000 hour requirement, you must
If more than 12 samples are used for more than 5000 hours of testing, then the combination calculation is meaningless. Because if you don’t care too much at this time
For 1000 hours, we can completely choose to use the direct push method after 6000 hours of testing, so that the test interval can be extended to 1000
Hours to reduce the test burden.
In summary, if the current requirements of the Energy Star bulb standard are compared, the calculation method not only fails to reduce the test burden, but greatly increases
Increased the burden of testing. However, this does not deny the rationality of this standard. The possibility of the standard being adopted still exists.
At the burden of the manufacturer, the certification body may make appropriate adjustments to the test requirements or calculation requirements.