GB/T 33721-2026Reliability test methods for LED luminaires (English PDF)

1 Scope

GB/T 33721-2026 is the Chinese national standard covering how the reliability of an LED luminaire is tested - the lumen maintenance over thousands of hours, the driver which usually fails before the LEDs do, the thermal cycling and humidity, and the statistics that turn the results into a stated life. It replaces GB/T 33721-2017 and has been in force since 1 November 2026, alongside the street and tunnel luminaire standards of this batch. It was issued on 30 April 2026 and takes effect on 1 November 2026, replacing GB/T 33721-2017. The document is under the responsibility of the China National Light Industry Council. This page is published from the official record of the 2026 edition; the clause text of a standard this recent is not yet in circulation, and the figures, limits and tables it contains are those of the document itself, delivered in full with the English translation.

14.1.2 Conditions for measuring luminaire parameters The luminaire operates under the operating conditions and performance temperature (tq±2)°C claimed by the manufacturer. If the manufacturer makes multiple claims regarding tq, try... The test should be conducted at the highest claimed tq.

14.1.3 Calculate and measure the unit current I'f of the LED module within the luminaire. Measure the input current of the LED module inside the luminaire, calculate I'f of the module unit according to different circuits, and determine the relationship between I'f and ANSI/IES. The correspondence between the module current If given in the LM-80 report. The measured results may be.

14.1.4 Measuring the temperature at point t's of the LED module inside the luminaire. The results of the measurement may be.

a) The luminaire's temperature at point t's does not exceed the minimum temperature at point t's in the ANSI/IESLM-80 report, i.e., t's <= tsmin, or the luminaire's temperature at point t's... The temperature is equal to either of the other two temperatures reported in the ANSI/IESLM-80 report;

b) The luminaire's temperature at point t's exceeds the minimum temperature at point t's in the ANSI/IESLM-80 report, but does not exceed the temperature reported in the ANSI/IESLM-80 report. The other highest temperatures at point ts in the report, i.e., tsmin

c) The temperature at point t's of the luminaire exceeds the maximum temperature at point ts in the ANSI/IESLM-80 report, i.e., t's > tsmax.

14.1.5 Typical estimates of light decay DeltaLO for commonly used secondary optical materials in luminaires Table 8 shows typical estimated values of light decay for commonly used secondary optical materials in lighting fixtures.

14.1.6 Typical estimates of optical attenuation DeltaLO using optical materials other than those in Table 8

14.1.6.1 According to the test methods in GB/T 16422.2, outdoor luminaires shall use method 1 of the cycle number, and indoor luminaires shall use method 5 of the cycle number. The method involves aging the lamp samples for 1200 hours. During the test, the samples are not powered on, and each 240-hour period is considered a test node. The samples are then removed from the aging test chamber. Remove the lamps and perform photoelectric parameter tests to collect data such as luminous flux and color coordinates.

14.1.6.2 A total of 3 samples were tested, all from the same batch produced by the same manufacturer. The 3 samples (a~c) were complete luminaires, tested according to method 14.1.6.1. Conduct the test according to the method outlined in Table 9 and record the data.

14.1.6.3 The deviation values of luminous flux maintenance rate and color shift values shall not exceed the provisions in Table 10.

14.1.7 Selection of light attenuation DeltaLO when using multiple optical materials superimposed on a luminaire

14.1.7.1 General Rules If the luminaire uses multiple optical materials, when selecting the estimated values from Table 8, it is necessary to consider the luminaire's operating environment and the t's point temperature of the LED chips. To make distinctions.

14.1.7.2 Luminaires designed for indoor environments When t's<=55°C, the optical decay DeltaLO of the outermost optical material given in Table 8 is used for subsequent testing and verification; When 55°C The higher value outside LO; When t's >85°C, the light decay of the innermost and outermost optical materials of the lamp must be considered simultaneously, and the estimated value of DeltaLO is LOinnerLOouter.

4 General test requirements

4.1 Test Environment Conditions Unless otherwise specified, the operation should be carried out in a non-convection environment with a relative humidity not exceeding 65% and a temperature of (25±1)°C, for stable working conditions. Performance parameters of the LED luminaires were measured while they were in operation. Measurements of non-performance parameters were conducted at an ambient temperature of 10°C to 30°C.

4.2 Power Supply Voltage Requirements Unless otherwise specified, all tests shall be performed at rated voltage and rated frequency, or at the most severe conditions if the manufacturer provides a voltage range. The test should be conducted at the operating voltage (generally the maximum operating voltage is selected). During the stabilization period, the stability of the power supply voltage and frequency should be within ±0.5%. Within the test, the tolerance during the luminous flux maintenance test is ±2%. During parameter measurements, the tolerance for power supply voltage and frequency should be ±0.2%. The total harmonic content of the power supply voltage should not exceed 3%.

4.3 Stability Criteria During the stabilization period, the luminaires should operate normally. Measure the light output and electrical power every 15 minutes. When the light output and electrical power reach a stable level within 30 minutes... A rate is considered stable when the difference between the three readings (maximum - minimum) is less than 0.5% of the average of the three readings. If in If stability cannot be achieved within 150 minutes, measurements can still be taken, but the observed fluctuations should be described.

4.4 Measurement of Initial Values The initial values of luminous flux, power input, temperature, and chromaticity shall be measured in accordance with the provisions of GB/T 29293.

4.5 Selection of Test Items Of the testing clauses listed in this document, Chapters 5 through 17 cover general testing requirements for LED luminaires, while Chapter 18 covers testing requirements for LED luminaire components. Regarding environmental adaptability requirements, relevant parties may refer to the appendix based on product functional characteristics, actual operating conditions, target performance requirements, and industry practices. Select appropriate reliability test items from list A. Implementation recommendations for the suggested terms should be confirmed through technical evaluation or contractual agreement.

5 Temperature Cycling Test

5.1 General Rules The temperature cycling test shall be conducted in accordance with Test Nb of GB/T 2423.22."Temperature change at a specified rate of change" and the following provisions.

5.2 Test Requirements The test shall be conducted in a test chamber that meets the requirements of GB/T 2424.5.The test temperature shall conform to Table 1, with a temperature tolerance of ±2K.

5.3 Test Procedure The experimental procedure for a single cycle is as follows:

a) The LED lights stabilize at the maximum test temperature, then the power is disconnected. The ambient temperature inside the test chamber is maintained at (10±)°C. 2) The rate of decrease is reduced to the minimum test temperature at K/min;

b) The LED lights were kept disconnected from the power supply for 50 minutes at the minimum test temperature, and then subjected to 10 cycles of 10 seconds on and 50 seconds off.

c) Connect the LED lights to the power supply;

d) The ambient temperature inside the test chamber increases to the maximum test temperature at a rate of (10±2) K/min;

e) The LED lights are kept powered on for 50 minutes at the maximum test temperature, and then the cycle of 10 seconds on and 50 seconds off is repeated 10 times.

5.4 Qualification Criteria After the test, the labels on the samples should not be cracked, curled or detached, the samples should not be obviously damaged, and the rate of change in optical properties should not exceed 10%.

Note. The rate of change in optical performance refers to the measured optical performance rate, obtained by selecting appropriate optical parameter measurement indicators (such as luminous flux, illuminance, luminance, luminous intensity, etc.) based on the characteristics of the product. The ratio of optical parameters after the experiment to those before the experiment.

6 Power switch test

The ambient temperature for power switch testing should meet the requirements of Table 2.

7.Accelerated service life test LED luminaires should operate continuously for 1000 hours under test conditions. The test temperature should meet the requirements of Table 3, with a temperature tolerance of ±2K.

8 Temperature shock test

For LED luminaires used in environments with rapid switching between cold and hot conditions, the test Na of GB/T 2423.22, specifying the switching time, should be followed. Temperature shock tests shall be conducted in accordance with the following provisions regarding "rapid temperature changes". The temperature shock test parameters shall conform to the provisions of Table 4.

9.Constant humidity and heat test LED luminaires used under high humidity conditions should meet the requirements of constant humidity and heat test. The test shall be conducted in a test chamber, and the test chamber shall meet the requirements of Chapter 4 of GB/T 2423.3-2016. During the test, the test chamber and test sample should first be placed under laboratory environmental conditions, and then the temperature inside the test chamber should be adjusted to 40°C± At 2°C, when the lamp's temperature tq is higher than 40°C, the test temperature is set according to tq, ensuring the sample reaches temperature stability. Then, within 2 hours, the sample inside the test chamber... Adjust the relative humidity to (93±3)%. After the temperature and humidity inside the chamber reach the specified values and stabilize, perform a power-on/off cycle, and start calculations simultaneously. The test duration and the on/off cycle time should comply with the specifications in Table 5, and the test duration is 168 hours. During the test, if the thermal protector... If protection is provided by extinguishing or reducing its light output, the thermal protector will be short-circuited.

10 High-temperature operation test LED luminaires used in high-temperature environments should meet the requirements of high-temperature operation tests. The test shall be conducted in a test chamber, and the test chamber shall meet the requirements of GB/T 2424.5. During the test, the test chamber and test sample should first be placed under laboratory environmental conditions, the sample should be powered on, and then the temperature of the test chamber should be set to no more than [a certain value]. The rate of change should be adjusted to 1K/min to the manufacturer's claimed maximum operating temperature of 10K, but indoor luminaires should not be below 40°C, and outdoor luminaires... The temperature should not be lower than 50°C, the temperature tolerance is ±2K, and the relative humidity inside the test chamber should not exceed 50%. The test should continue until the temperature inside the chamber reaches the specified value and stabilizes. After determination, the test should continue for 168 hours. If the manufacturer has specific instructions regarding the test duration, the manufacturer's statement should be followed. During the test, if heat preservation is required... If the thermal protector protects itself by turning off or reducing its light output, then the thermal protector should be short-circuited. When the specified test duration ends, the test sample should remain powered on inside the test chamber, and then be tested at a speed not exceeding 1 K/min. The rate of change reduced the temperature to the laboratory ambient temperature and stabilized it for 2 hours. After the test, the sample should not show any obvious damage, and the rate of change in optical properties should not exceed 10%.

11 Low Temperature Start-up Test LED luminaires that operate in low-temperature environments should meet the requirements of low-temperature start-up tests. The test shall be conducted in a test chamber, and the test chamber shall meet the requirements of GB/T 2424.5. During the test, the test chamber and test sample should first be placed under laboratory environmental conditions, and then the temperature of the test chamber should be set at a rate not exceeding 1 K/min. The rate of change is reduced to the manufacturer's claimed minimum operating temperature, such as -20°C for indoor luminaires and -40°C for outdoor luminaires if no claim is made. The temperature tolerance is ±2K. After the temperature inside the chamber reaches the specified value and stabilizes for 2 hours, the sample is subjected to 300 cycles of 1 minute on and 19 minutes off. The sample should be able to light up within 5 seconds at low temperature after the cycle is completed. When the test is finished, the test sample should be left in the test chamber, and then the temperature should be restored to normal at a rate not exceeding 1 K/min. The laboratory ambient temperature was stabilized for 2 hours. After the test, the sample should show no obvious damage, and the rate of change in optical properties should not exceed 10%.

12 Extreme temperature storage

12.1 High-temperature storage When the manufacturer claims a maximum storage temperature higher than 70°C, a high-temperature storage test should be conducted to verify the LED luminaire's performance in extreme high-temperature environments. Storage and transportation capacity under the environment. The test shall be conducted in a test chamber, and the test chamber shall meet the requirements of GB/T 2424.5. During the test, the test chamber and test sample should first be placed under laboratory environmental conditions, and then the temperature of the test chamber should be set at a rate not exceeding 1 K/min. The rate of change should be adjusted to the manufacturer's claimed maximum storage temperature, with a temperature tolerance of ±2K, and the relative humidity inside the test chamber should not exceed [missing value]. 50%, after the temperature inside the chamber reaches the specified value and stabilizes, the test should continue for at least 72 hours, unless otherwise specified by the manufacturer. The manufacturer's claim should be used. When the specified test duration ends, the test sample should remain in the test chamber and then be changed at a rate not exceeding 1 K/min. The temperature was restored to the laboratory ambient temperature and stabilized for 2 hours. After the test, the sample should show no obvious damage, and the rate of change in optical properties should not exceed 10%.

12.2 Low-temperature storage When the manufacturer claims a minimum storage temperature below -10°C, a low-temperature storage test should be conducted to verify the LED lighting fixture's performance in extreme low temperatures. Storage and transportation capabilities in the environment. The test shall be conducted in a test chamber, and the test chamber shall meet the requirements of GB/T 2424.5. During the test, the test chamber and test sample should first be placed under laboratory environmental conditions, and then the temperature of the test chamber should be set at a rate not exceeding 1 K/min. The rate of change is adjusted to the manufacturer's claimed minimum storage temperature, with a temperature tolerance of ±2K, until the temperature inside the chamber reaches the specified value and stabilizes. Afterwards, the test should continue for at least 72 hours. If the manufacturer has specific instructions regarding the test duration, the manufacturer's statement should be followed. When the specified test duration ends, the test sample should remain in the test chamber and then be changed at a rate not exceeding 1 K/min. The temperature was restored to the laboratory ambient temperature and stabilized for 2 hours. After the test, the sample should show no obvious damage, and the rate of change in optical properties should not exceed 10%.