LED tunnel light is a type of tunnel light that is used for large-scale floodlighting in tunnels, workshops, large warehouses, venues, metallurgy, various factory areas, engineering construction, and other places. It is most suitable for beautifying urban landscapes, billboards, and building facades.
>>>>Advantages of LED tunnel lights:
LED is a solid-state semiconductor device that can directly convert electricity into light. Compared to traditional road tunnel lighting sources such as sodium lamps and metal halide lamps, LED light sources have the following advantages:
(1) Low light attenuation: If the heat dissipation conditions are good, the first 10000 hours of LED light attenuation are positive, the first 10000 hours of light attenuation are 3% to 10%, and the first 50000 hours are basically 30%, far lower than ordinary road lighting sources, and the light emission is more stable.
(2) High color rendering: Generally, the color rendering of LED is about 70-80, and it is even higher if using tricolor fluorescent powder; Generally, high-pressure sodium lamps range from 20 to 35, while low-pressure sodium lamps have lower brightness. Therefore, even though traditional light sources have higher brightness than LEDs, their visual effects are inferior to LEDs. "Not the brightest, but the clearest to see" should be a direction for the development of LED light source applications.
(3) Lifespan: The lifespan of LED is higher than that of general road tunnel lighting sources, and now generally exceeds 50000 hours.
(4) Price: Although LED lamp heads are currently priced higher than traditional lighting fixtures, their prices are continuously decreasing with the maturity of manufacturing technology. A set of high and low pressure sodium lamps generally costs around 2000 yuan, while the cost of cables and other accessories is higher than that of LED cables.
In addition, LEDs also have advantages such as high maintenance factor, good safety performance, no flicker, and energy conservation and environmental protection.
>>>>Prospect Challenge
At present, among the light sources used in tunnel lighting applications, high-pressure sodium lamps have been widely used due to their high luminous efficiency (up to 120lm/w). However, high-pressure sodium lamps still have some difficult problems to overcome in tunnel lighting, mainly poor color rendering and limited range of light source power selection (usually only 250W and 400W can be selected), especially in internal section lighting. On the one hand, high-pressure sodium lamps do not have small power, and on the other hand, the glare and flicker caused by point like strong light sources are more serious. In some long tunnels, straight tube fluorescent lamps have also been applied due to their high color rendering and linear illumination with good visual induction. However, due to the short lifespan of fluorescent lamps, usually only about 8000 hours, they often need to be replaced, greatly increasing the maintenance cost of the tunnel. In addition, the power of fluorescent lamps is relatively small, and they cannot meet the requirements in areas that require high illumination, such as the entrance section, transition section, and exit section. In recent years, with the maturity of electrodeless lamp technology, due to the elimination of electrode factors, electrodeless fluorescent lamps have a longer lifespan and can achieve higher power compared to traditional fluorescent lamps, which makes electrodeless lamps advantageous in tunnel lighting applications. However, the light-emitting surface of the infinite pole lamp is relatively large, and the optical efficiency of the entire lamp is low during optical design.
Although there are still many difficulties and challenges in the large-scale application of LED tunnel lights, such as the imperfect standards of LED lighting products, the negative impact of some inferior products on market promotion, and the high initial purchase cost of LED tunnel lights. These all bring pressure to the large-scale market application of LED tunnel lighting products, but these pressures are inevitable for any new technology or product in the early stages of promotion and application. However, with the further development of high-power white LED technology, the continuous maturity of LED tunnel lighting thermoelectric integrated system technology, and the further enhancement of people's awareness of energy conservation and environmental protection, LED technology will surely create a new future for the semiconductor lighting industry in the field of tunnel lighting applications. Applicable environment
The shell of the LED tunnel light is made of environmentally friendly alloy materials with high strength and good toughness. The transparent parts are reinforced tempered glass, which is dustproof, waterproof, corrosion-resistant and rust proof. Has strong resistance to strong collisions and impacts; Multi channel shock-absorbing structure and high-tech surface spraying treatment ensure that various high-frequency vibrations at close range do not affect the lighting fixtures, and can work stably for a long time in high-frequency vibrations and humid, high-temperature environments such as workshops, roadbeds, and tracks. Good electromagnetic compatibility, will not cause interference to the transmission network.
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Installation method
LED tunnel lights can be installed in various ways such as ceiling mounted, suspension rod mounted, seat mounted, and wall mounted, making operation more convenient. Adapt to the lighting needs of different work sites. The integrated design of lighting fixtures and electrical boxes has strong overall reliability, low failure rate, and safer and more convenient use and maintenance. LED tunnel lights can use intelligent control technology to achieve self dimming control and save energy. Basic situation of LED tunnel lighting: Long tunnels are equipped with lamps according to the double hole one-way driving mode. Tunnel lighting is divided into entrance section, transition sections 1, 2, and 3, basic section, and exit section; The functions of the lighting fixtures are divided into three types: reinforced lights, full day lights, and emergency lights. Double sided cloth lights, with a lamp installation height of 5.5 meters.
Highway tunnel lighting has its own characteristics, which are different from ordinary road lighting. In design, it is necessary to consider the following points:
1. The road surface should have a certain level of brightness
2. The tunnel walls should have a certain level of brightness
3. Design various influencing factors such as vehicle speed, traffic volume, and route alignment
4. Determine the lighting level comprehensively from the aspects of driving safety and comfort
5. Human visual adaptability, especially in the entrance and exit sections of tunnels
6. Tunnels also require lighting during the day, and the issue of lighting during the day is more complex than at night.
To achieve energy conservation, improve lighting effects, and ensure driving safety and comfort in tunnel lighting, the following aspects can usually be considered:
1 Brightness
Due to the much higher brightness outside the tunnel during the day compared to inside, drivers need a certain amount of adaptation time for their vision when driving into the tunnel before they can see the situation inside the tunnel clearly. This phenomenon is called "adaptation lag". If there is no appropriate transition, it will create a black hole phenomenon, causing the driver to temporarily lose normal visual function, which will bring certain safety hazards. The black hole phenomenon is a visual problem that occurs before entering a tunnel, and it is also the most important issue in tunnel lighting. Tunnel lighting is usually divided into entrance lighting, interior lighting, and exit lighting. The brightness of daytime tunnel entrance lighting should be determined based on the brightness outside the tunnel, vehicle speed, field of view at the entrance, and the length of the tunnel. The threshold section is designed to eliminate the "black hole" phenomenon, and the lighting level in the transition section gradually decreases, providing drivers with time for visual adaptation to dark conditions.
2 Brightness uniformity
Good visual function not only requires a good average brightness, but also requires that the average brightness on the road surface should not differ too much from the minimum brightness. If the brightness difference in the field of view is too large, the bright part will form a dazzling light source, and the change in brightness will bring about a certain flicker effect, which will then affect vision. The visual effect of the human eye will significantly deteriorate, and visual fatigue will also increase.
The overall brightness uniformity U0 refers to the ratio of the minimum brightness to the average brightness on the road surface inside the tunnel, while the longitudinal uniformity U1 refers to the ratio of the minimum brightness to the maximum brightness on the lane axis. If there are continuous and repeated bright and dark stripes on the road surface, known as the "zebra effect", road users traveling on this lane will feel very annoyed. This issue involves human psychology, but it can also endanger road safety. Vertical uniformity is mainly used to evaluate the magnitude of the "zebra effect".
3 Glare
The formation of glare is due to the presence of extremely high brightness or brightness contrast in the field of view, which reduces visual function or makes the eyes feel uncomfortable. The glare in tunnel lighting can come from oncoming vehicle headlights, tunnel lighting fixtures, high brightness outside the tunnel exit, etc. Glare can reduce people's ability to recognize obstacles and endanger driving safety. Tunnel lighting fixtures should adopt a cutoff type and adopt special technical measures to eliminate direct and reflected glare, forming diffuse reflection and allowing light to enter the human eye very softly. The International Commission on Illumination uses the relative threshold increment (TI) to measure the decline in visual function caused by glare, also known as disability glare. In the tunnel lighting standard of the European Commission for Standardization (CR 14380:2003E), the provisions for disability glare are as follows: during the daytime, the relative threshold increment (TI) of the tunnel threshold section and internal section, as well as the entire tunnel at night, must be less than 15%.
4 Strobe effect
Strobe refers to the disturbance caused by the discontinuous arrangement of lighting fixtures in longer tunnels, which constantly stimulates drivers with changes in brightness and darkness. It is related to the brightness changes of light and dark, the frequency of light and dark changes, and the total duration of flicker. These three factors are related to the optical characteristics of the lighting fixtures used, the speed of the vehicle, the installation spacing of the lighting fixtures, and the length of the tunnel. Generally speaking, the flicker phenomenon caused by frequencies less than 2.5 and greater than 15Hz is acceptable.
If the speed of the vehicle is 60km/h, which is 16.6m/s, and the installation spacing of the lighting fixtures is 4, the frequency of flicker is about 4.2Hz. When designing, appropriate lighting fixture installation spacing should be considered. If the frequency of the flicker is between 4Hz and 11Hz and lasts for more than 20 seconds, it will cause significant discomfort to the driver.
5 Lighting Control
Advanced lighting control methods are important techniques for reasonable energy conservation while ensuring visual conditions and meeting tunnel lighting requirements. The purpose of lighting control is to be able to change the lighting level of the tunnel at any time. Due to cloudy, rainy, or dusk conditions, the brightness outside the tunnel entrance is much lower than usual. Therefore, appropriate measures should be taken to reduce the level of lighting at the entrance section to minimize unnecessary energy waste. In tunnel lighting, various dimming devices or control devices can be used to adjust and control the illumination of the tunnel lighting environment or the turning on and off of lights based on factors such as daytime, nighttime, and traffic volume. At present, most foreign countries use photosensitive devices, dimmable optoelectronic rectifiers, and other components to form intelligent lighting systems, which reduce the overall brightness and energy consumption of lighting fixtures in tunnels; At the same time, ensure that the brightness uniformity of the tunnel remains unchanged.
