Tunnel lighting design something you must know

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Something you need to know when you make the LED tunnel lighting design

tunnel lighting design something you must know

LED tunnel light is widely used for large-area floodlighting in tunnels, workshops, large stadiums, venues, metallurgy, various factories, engineering construction, and other places. The LED tunnel lighting fixtures are also suitable for urban landscapes, billboards, and buildings.

The factors considered in tunnel lighting design include tunnel length, line type, interior decoration, type of road surface, unmanned roads, the structure of link roads, design speed, traffic volume and types of cars, etc. At the same time, the light source color, lamps arrangement, and lamps installation must also be considered. The design of tunnel lighting is to solve a series of problems such as illumination level, brightness outside the cave, and adaptability of the human eye.

Energy saving in tunnel lighting is a requirement for light sources, lamps, lighting methods, etc. The energy-saving includes lighting design energy saving and management energy saving, among which lighting design energy saving is the most important energy-saving measure, which includes the adoption of novel and reliable design concepts and reasonable standard values, as well as the use of high-efficiency lights, high-efficiency lamps, increased light reflectance, and lighting control energy saving.

Compared with traditional lights, the biggest advantage of LED is energy-saving and stability. Therefore, based on the advantages and characteristics of LED, improving the efficiency of LED chips and reasonable light distribution design to improve the overall efficiency of lamps are important issues that LED tunnel lighting needs to solve.

The luminous efficiency of the LED light source is a basic indicator to measure the efficiency of the tunnel lights. According to the actual requirements of the LED tunnel light, the light efficiency must reach a certain level to meet the needs of replacing the traditional sodium lamp and metal halide lamp.

In recent years, with the continuous update and development of LED chips, packaging, and light distribution technology, the efficiency of LED light sources has increased to a new level. The efficiency of NOVA series LED tunnel lights is much higher than the current LED tunnel lighting products.

Ordinary tunnels have the following special visual problems:

  • Before entering the tunnel (in daylight): As the brightness difference between the inside and outside of the tunnel is extremely large, looking from the outside of the tunnel, a “black hole” phenomenon will be seen at the entrance of the tunnel with insufficient lighting.
  • After entering the tunnel (daylight): After the car enters the tunnel from the outside of the bright hall, even if it is not too dark, it takes a certain period of time to see the conditions inside the tunnel, which is called the phenomenon of “compliance lag”.
  • Tunnel exit: In daylight, when a car passes through a long tunnel and approaches the exit, the exit looks like a “white hole” because of the extremely high external brightness seen through the exit, which will show strong glare. It will make the drivers feel uncomfortable. In the night, what you see at the exit of the tunnel is not a bright hole but a black hole, then the driver can’t see the lines of the external road and the obstacles on the road.

The above several special visual problems put forward higher requirements for tunnel lighting, and the effective treatment of these visual problems can go through the following aspects.

Tunnel lighting is generally divided into five sections: approach section, entrance section, transition section, an intermediate section, and exit section. Each section has a different function.

  • Approaching section: The approaching section of the tunnel refers to a section of road close to the tunnel entrance. The starting point of the approaching section is a lighting parking sight distance from the entrance. The lighting parking sight distance is set according to the road tunnel lighting design rules. By the way, the approaching section located outside the tunnel, its brightness comes from the natural conditions outside the cave, without artificial lighting, but since the brightness of the approaching section is closely related to the lighting inside the tunnel, it is customarily referred to as a lighting section.
  • Entrance section: The entrance section is the first lighting section after entering the tunnel. The entrance section is also called the adaptation section. This section requires artificial lighting.
  • Transition section: The transition section is the lighting section between the entrance section and the middle section. This segment is used to solve the problem of the driver’s vision adaptation from the high brightness of the entrance section to the low brightness of the middle section.
  • Intermediate section: After the driver drives through the entrance section and the transition section, the driver’s vision has completed the dark adaptation process. The task of lighting in the intermediate section is to ensure safety and stability in the tunnel.
  • Exit section: During the day, the illuminance of the exit section of the tunnel is the same as the illuminance of the entrance section, and should be higher than the illuminance value in the tunnel; at night, on the contrary, it should be lower than the illuminance value in the tunnel. When there are street lights outside the tunnel, the brightness of the road surface in the tunnel should not be Lower than 2 times the outdoor brightness value.

Problems in the process of motor vehicles passing through the tunnel

Blackhole phenomenon

In the daytime, the eyes of motor vehicle drivers have adapted to outdoor natural light lighting of more than 100,000 lx and thousands of cd/m2. When the eyes turn to a tunnel environment with a brightness of only a few cd/m2, human eyes have a limited perception of the difference in brightness, which presents a compliance lag. , You will see a black cave, and you can’t recognize the state in it. The phenomenon of seeing a completely black cave in a bright environment like this is called a black hole phenomenon. Once the black hole phenomenon appears, as the motor vehicle approaches the tunnel, the driver’s visual interval is shortened, making it impossible to drive safely. The black hole phenomenon is a visual problem that occurs before entering the tunnel, and it is the most important problem in tunnel lighting. In order to avoid the occurrence of black holes, sufficient brightness should be ensured in an interval from the beginning of the tunnel entrance. This partial length is slightly longer than the safe braking interval of motor vehicles.

When entering the tunnel, due to the large brightness difference between the inside and outside, there is a delay in compliance, and the driver’s vision cannot quickly adapt to the brightness of the tunnel, and it is difficult to see the inside of the tunnel. In order to avoid the occurrence of this situation, the brightness of the tunnel entrance should be slowly reduced with the speed of visual compliance, the brightness should be smoothly transitioned, and the brightness reduction should be stopped step by step, but the ratio of the previous level of brightness to the next level of brightness should not exceed 3:1, and the brightness of the following 2m high walls cannot be lower than the corresponding uniform road brightness.

Passing through the tunnel

Considering that the exhaust gas emitted by cars in a long tunnel with heavy traffic flow, because the exhaust gas cannot quickly dissipate, it forms smoke, absorbs and scatters light, reduces visibility, and makes visual recognition difficult. The car lights are greatly affected by automobile exhaust, so the brightness of the road 100m ahead is halved and can’t meet the visibility requirements.

Approaching the tunnel exit

Looking through the exit, the external brightness is extremely high. The exit looks like a bright hole with severe glare, and the exit becomes a white cave. This is called a white hole phenomenon. With the white hole as the background, the black silhouettes of motor vehicles are easy to identify. But it’s difficult to see the silhouette of the car behind the large trucks. Near the exit of the tunnel with heavy traffic, the lighting used to identify the large and small vehicles is called exit lighting. Normally the length of the lighting interval is tens of meters only.

Driving out of the tunnel at night

At night, before driving out of the tunnel, the outside of the tunnel also becomes a kind of black hole. It is impossible to see the alignment of the road and the existing obstacles. At this time, you should stop lighting on the road in an interval that is greater than the safe braking interval, which is approximately equivalent to a few seconds of driving the motor vehicle, to achieve an appropriate level of brightness.

Application of LED products in tunnels

YIBAI LED LIGHTING provides an intelligent dimming control system that can automatically adjust the intensity according to the light intensity in the tunnel. Compared with the traditional tunnel lamps, it saves 50% of electricity, and the lifespan of the lighting fixtures is 6-8 times that of traditional tunnel lamps, which greatly reduces the cost of daily maintenance.

In the past 10years, YIBAI has delivered world-class LED tunnel lighting products & Roadway LED lighting fixtures all over the world. For any questions or need on LED lighting fixtures, please feel free to contact us via info@yboptotech.com, YIBAI LED LIGHTING, high quality LED lights with a professional engineer team that will support you within 24 hours!

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