Lighting quality standard
The road is usually required average illumination and uniformity of the two indicators. The former unit is LX, that is, each LM2 level irradiation area, a uniform distribution of 1 LM luminous flux; the latter is the minimum level of illumination and the average ratio of water to light. In fact, there is a big difference between the luminance distribution and the illuminance distribution. The actual situation of the visual condition can not be given by using the illuminance of road surface as the index of road lighting. Therefore, it is recommended that the quality of road lighting be measured by four indicators of road surface brightness, uniformity, glare and induced. Brightness is the amount of light reflected on the surface area of the road, using cd/m2 as a unit. Evenness is the uniformity of luminance distribution on the road surface. The uniformity of the driver's visual comfort is equal to the ratio of the minimum and average luminance of the road surface. Even if the average brightness is high, but the uneven distribution of the brightness of the road, where the difference between light and shade, obstacles are difficult to find. Glare is the direct glare of the driver's eyes, so that they are not comfortable, visual barriers, can not see the phenomenon of objects. Glare to the degree of discomfort of the eyes with subjective feeling of glare index G evaluation. Recommended by the International Commission on illumination (G=9): G=1, intolerable; G=3, interference; G=5; allowable limit; G=7; relatively satisfactory; no effect. Glare is related to the brightness of the light source, the angle between the line of sight and the light source, and the average luminance of the road surface. Induction is used to inform the driver of the road ahead of the road, ups and downs, cross, the traffic flow of the relevant information. International Lighting Commission suggested that the city road, highway pavement brightness 2cd/m2, longitudinal uniformity of 0.7, G = 6. Japan has adopted the pavement brightness as the road lighting indicators. The United States and many other countries still use illuminance for road lighting standards. Illumination and brightness can be derived from each other, P is equal to the brightness of road illumination brightness by coefficient of the point.
Lighting device and its arrangement
At present, lighting road lighting with high pressure sodium lamp, low voltage lamp, electrodeless lamp, halogen lamp, fluorescent lamp, etc.. Incandescent lamp, high pressure mercury lamp, low pressure sodium lamp due to the performance of the light source has been gradually eliminated. Lighting should be reasonable use of light to prevent glare. The light emitted by the illumination device needs to be irradiated along the required angle, and the utility model is designated on the surface of the road, and the light distribution is uniform. In order to reduce glare, the light can be controlled above the maximum light intensity.
Lighting device for road lighting can be divided into light interception, half light and light interception of three types.
The light interception type: Lighting exposure to the road outside the light source does not exceed the rated 10% lumens of light distribution control, along the road, the small glare. Suitable for main streets, main roads and highways.
The half light illuminator: exposure to the road outside the light source does not exceed the rated 30% lumens, control the light distribution along the road. Suitable for general grade streets.
The not light interception type: flux lighting equipment on maximum intensity above the unrestricted, glare, only minor street street in the surrounding environment or traffic very bright. The range of the illuminator is determined by the elevation angle of the beam, which is divided into three types: short range, medium range and long range.
According to the form, a section of a road width, vehicles and pedestrians, lighting device can be used on both sides of the road, on both sides of the symmetrical arrangement, staggered arrangement, double side fork road separates the island layout and the central suspension layout form. The high road lighting mode is adopted in the road intersection. In general, the width of more than 20m of the road, Yingbin Road, can be considered symmetrically on both sides of the layout; the road width of more than 15m, can be considered on both sides staggered layout; narrow roads can be arranged on one side. In the intersection of roads, corners, ramps, railway crossings, pedestrian crossings and other special locations, are generally equipped with lighting, in order to facilitate the driver and pedestrians to identify the road situation, its brightness standards are higher. The inner and outer sections of the tunnel and the transition section of the transition section from the urban area to the suburban road should consider the adaptability of the driver's eyes to the light. The power of the illuminator, the installation height and the vertical pitch are important parameters in the design of light distribution. Combination of these three factors, can be satisfied with the lighting effect.
The quality standard of road lighting
The quality standard of road lighting mainly in the following four aspects.
(1) brightness level
The average brightness of road by road grade have different brightness requirements. General highway and main road asphalt pavement needs more than 2cd/m2 brightness requirements. Secondary roads and auxiliary roads or residential road requirements are relatively low. Specific reference to the current road
Road lighting design standard.
(2) average illuminance
Average refers to the average illuminance value is all road illumination, lighting intensity, generally represented by lx.
Road lighting should work hard for the discomfort glare is limited in a certain range. Generally use the G value to express.
General, G=7 (G=1 unbearable, commonly known as light pollution)
(4) visual induction
Let the driver can immediately identify the direction of the road at a distance, especially the road will follow his own direction.
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