What is an LED?
LED is the common abbreviation for a Light-Emitting Diode. As indicated by its name, the LED is a diode that emits light. Because LEDs are illuminated by the movement of electrons in semiconductor material, they last for an amazing amount of time, give off virtually no heat and don’t contain any hazardous substances. Highly efficient and environmentally friendly, LEDs are widely used to light homes, offices, shops, hospitals and hotels as well as outdoor spaces.
What are the benefits of LED solutions?
•Big energy savings – over 60% in comparison to traditional street lighting
•Good colour rendering, making colours more natural
•Long life – up to 100,000 hours, resulting in less maintenance
•Uniform, high quality white light. LED lighting provides better facial recognition for security and CCTV cameras and therefore helps to make areas safer.
•LEDs can be dimmed when light is not needed, resulting in additional energy savings. LEDs can also be connected to sensors and controls and networked so that they can be controlled remotely.
Are LED’s new?
No. LED’s were first developed around 1962 and have since been used as a lighting source within many commonly used electronic devices, such as television screens, computer monitors and tablet pc’s.
However, LED technology has been developed for use in many lighting applications over the last 10 years. It is now used in many highway lighting products such as traffic signals, traffic signs and bollards. Street Lighting is the latest area for this technology to be used.
How long do LED’s typically last?
The life span of the selected LED is designed to operate for around 100,000 hours, which is significantly (around 6 times) longer than that of most incandescent, fluorescent or High Intensity Discharge (traditional street lighting) lamp sources.
Like all light sources, LED sources slowly fade over time. This reduction in light output over time is known as light output degradation, or lumen depreciation.
White light sources used for general illumination are commonly considered to be at the end of their useful life when their light output falls below 70% of initial output. In this case after 100,000 hours. After this period the light output would not provide the right levels of lighting to the area to be lit.
How long is 100,000 hours?
Street Lights switch on when the ambient light falls to a certain level, typically 35 lux and will operate for shorter hours in the summer months and longer during the winter months, to reflect the changes in the seasons.
Therefore, over a typical year a street lighting unit operating in these conditions will be switched-on for around 4,100 hours. Based on these annual hours of operation, the LED street lights are expected to operate between 20-25 years.
