LED and lifetime expectancy: What you need to know
What do you need to know about LED and life expectancy? Find the answer in this blog!
In this blog, we will give all the information you need about LED and life expectancy. In the bottom of the blog, you will find an exciting video about this topic with the CEO of Lumega Rune Larsen.
Extraordinary life expectancy
Traditional lighting sources such as halogen lamps, incandescent bulbs and fluorescent tubes all have the same issue: short life expectancy. This is a challenge for everyone using these lighting sources because it can be a struggle often to have to replace the bulbs or tubes.
This challenge can be solved by using LED instead of traditional lighting sources. You see, LED is well known for its superior life expectancy and thus the general life expectancy of LED is as much as 50.000 hours.
What do I need to know when it comes to LED and life expectancy?
It is important to remember that the life expectancy of LED partly depends on other factors than the LED’s life expectancy itself. Thus, there exist several exterior factors of which you should be aware.
You need to remember that LED, that is the light source, and the driver, that is the transformer, co-create a collective system and therefore are mutually dependent. Therefore, it is necessary to be aware of the specifications of the driver that you use because it can cause trouble for the life expectancy of the LED if the driver’s life expectancy is shorter.
Furthermore, it must also be considered which temperature conditions there exist the location where the LED is installed. If the product is installed in, for example, a sauna the life expectancy is shorter than if it is installed in a refrigerator. Normally, the life expectancy is calculated based on a room temperature of 25 degree Celsius and this is, for example, a normal temperature in an office.
Additionally, it is important to remember that LEDs, like all other technical devices, gradually lose their yielding capacity over time. This entails that LEDs do not perform optimally throughout their entire lifetime even though the LEDs continue to operate.
In relation to this, it is necessary to become familiar with various standards which are important when using LED lighting.
Standard for luminous flux
The standard for luminous flux measures how much light which is projected from the lighting source in a certain amount of time and this is what is called the LEDs lifetime expectancy.
LED life expectancy can be defined as the operational time period during which a LED will maintain a certain percentage of its original luminous flux. The life expectancy is measured in relation to a chosen percentage of the original luminous flux of the LED and the life expectancy is described as Lp. Lp can be characterized as a durability measurement of the life expectancy. Thus, an example is L70 which means that it has been measured at which number of hours the luminous flux has dropped to 70% of the original luminous flux.
As an example, we use one of the most common standards for reduction or deterioration of the luminous flux, meaning the light projected, over time:
- The standard L70: If a LED is measured using this standard we will get to know how many hours the lighting source can project light before its luminous flux has decreased to 70 % of the original luminous flux.
For example, a lighting source is measured to L70 after 50.000 hours. From this, we can tell that the LEDs luminous flux has dropped to 70 % of the original after having been used 50.000 hours. Thus, it is important to know that from the LED is installed and the next 50.000 hours the luminous flux will gradually decrease to 70 % of its starting level. However, this does not mean that the LED will stop operating after 50.000 hours only that it will only have a luminous flux of 70 %. After that, this percentage will drop gradually for the rest of LEDs operating life.
Below you see a graph which illustrates the standard of L70 for a certain LED model being NS11 at a normal temperature of 25 degrees Celsius.
Standard for average life expectancy
The standard for LEDs average life expectancy measures the average life expectancy for a specific LED model statistically measured through tests carried out on a lot of copies of the LED model.
The average life expectancy can be defined at the life expectancy which can be ascribed to a specific LED model based on statistical testing during which a median of the model’s operational life expectancy is found.
It the manufacturers responsibility to specify the average life expectancy as well as a failure rate. The measure of average life expectancy is Bp and is measured in hours and p stands for the percentage.
As an example, B10 can be used to illustrate the average life expectancy:
- The standard B10: If a LED model is measured according to this standard, we can know how many percentages of the copies of the LED model which have technical failures which entail that it cannot function a scheduled number of hours. For example, a model is measured to have a B10 at 30.000 hours, from which we can tell that only 10 % of the tested products showed went wrong within the first 30.000 hours.
Standard for failure rate
In combination LP and Bp can show how many of the products’ luminous flux of a specific model which have decreased a certain percentage after a certain number of hours. To give an example L70 B20 can be used:
- The standard L70 B20: B2o expressed the failure rate and shows a failure rate of 20 % at a certain number of hours, for example, 50.000. Thus, L70 B20 means that the luminous flux of the LED model has dropped by 30 % after 50.000 hours and that only 10 % of the tested copies of the model are defective.
The testing method TM-21
With this testing method, the consumer can achieve long-term life expectancy information of the LED lighting sources. The method consists of two steps:
- The LED lighting source is tested with L80.
- The data is compared to data already collected so valid life expectancy projections can be made. These projections also take into account several exterior factors such as temperature.
TM-21 is a demanding and comprehensive measurement method. The method requires that the specific LED model is tested in 6.000 hours after which the life expectancy can be stated under TM21. The method’s complexity and magnitude imply that not many manufacturers offer products tested under this method. However, in Lumega we use the TM-21 method because we want to provide the best possible life expectancy projections of your products for the benefit of our customers.
Video about LED and life expectancy
If you want to watch a video about LED and life expectancy starring Lumega's CEO Rune Larsen you can watch the video below. In the video, Rune will, in short, inform you of everything you need to know on this topic.
How can we help you?
In Normsym we focus on the quality of light and life and we offer LED products with the newest lighting technology on the market. At Lumega, we offer numerous LED solutions that will fit perfectly into every project and we can help you design the ideal LED solution for your specific needs and wants.
Contact us to learn more about the impressive benefits of LED and start improving your lighting solution with LED today.
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