Many stores and suppliers claim that their LED flexible strips or neon flex will have a lifespan in excess of 30,000 hours – often even 50,000 hours, equating to many years of life. What exactly does this lifespan mean and is it reliable? This article will help you understand what these quoted lifespans actually mean.
There are some basics to understand:
The lifespan of an LED luminaire is not always the same thing as the lifespan of the LED chip
The term lifespan is a misnomer when describing the LED chip
Later in this article we will explain why the lifespan of the LED luminaire is sometimes different to the lifespan of the LED chip. For now, we will focus on the lifespan of the LED chip, as this is actually what that quoted figure, of say 30,000 hours or 50,000 hours is describing. Just knowing a figure of 50,000 hours is actually meaningless since that figure is out of context. If needs to be quoted with what we call an “L rating”. It should read something like L70 at 50,000 hours which would mean that the LED will be at no less than 70% of its original brightness after 50,000 hours.
There is are two international standards called LM-80 and TM-21 which were developed to bring some consistency to how LED lifespan is measured and reported upon. They allow for measurements to be taken over a relatively short time span and extrapolated to predict the brightness of the LEDs over time. It is in effect a standard to measure lumen depreciation (the decrease in brightness over time). Why? By their physical nature, if LEDs are used correctly electronically, they should not fail but will rather simply get dimmer over time until their brightness is no longer useful. These tests and their results don;t tell the full story of the lifespan of a luminaire but are a valuable contribution, because a luminaire often consists of much more than LED chips. Often there are other electronic circuits including power supplies which have their own lifespan factors.
The LM-80 and TM-21 tests and projections give a view on how an LED will perform (brightness and colour) over time at certain temperatures and currents. This is important – since a claim of L70 at 50,000 hours is a little meaningless unless you know at what temperature the figure was measured. The LM-80 tests should be performed at three different temperatures – at 55°, 85° & a temperature selected by the manufacturer, let’s say 25°. So what you really want to know are the different L values at different temperatures so that you can assess the predicted lumen maintenance for your particular installation conditions. The “lifespan” will also always decrease as the operating temperature increases.
Eg: L70 at 50,000 hours at 25° but at 55° L70 drops to 40,000 hours and at 85° L70 drops to 30,000 hours.
Now it’s important to note that no single factory has ever tested a luminaire for 50,000 hours. LM-80 states that tests be performed for no less than 6,000 hours and then TM-21 states that you can project up to a maximum of 5 times the LM-80 test time.
LUMUL ensures that our PVC and Silicone Neon Flex are appropriately tested so that we can accurately give you meaningful L70 lifespan predictions.