4.5.6. Commercial Center Lighting

Commercial areas are high-brightness areas. The average illuminance level of an entire shopping center (including pedestrian streets) and a square floor in Shanghai is no less than 20lx, and the uniformity (Emin/Eav) is 0.1–0.3. The vertical illumination at 1.5 m above the ground facing the viewing direction should be greater than 16 lx of uniformity (Emin/Eav) ≥ 0.2 [23]. Article 34 of the draft for comments in Guangzhou refers to the timing of signage lighting in stylistic and commercial places. The residential community and surrounding cultural and commercial establishments shall be provided with advertisements and signs that do not have outdoor lighting functions. If the surrounding interference light exceeds the technical requirements and causes complaints from residents, the city managemen<sup>t</sup> comprehensive law enforcement department shall enforce the relevant regulations. Businesses should deactivate ads, logos, and signboard lighting at night before 23:30. This article only regulates the lighting time of style and commercial venues, which fully reduces residents' complaints and the problem of urban light pollution [24]. No such relevant regulations and restrictions exist in Beijing and Tianjin.

## 4.5.7. Administrative Office Lighting

Administrative office areas belong to medium-brightness areas. The ambient lighting in the prescribed area of Shanghai should maintain the outdoor lighting level until the turn on/off light period and then reduce the minimum requirements to ensure pedestrians' safety and security. After public illumination is reduced, the average vertical illumination on a floor of an office building or industrial plant floor should be less than 4lx, and the average illumination on the surrounding road should be no more than 2lx. However, this regulation only addresses safety-related issues and does not address lighting restrictions or light pollution restrictions [23]. Other Chinese cities have no laws addressing lighting related to administrative offices.

### 4.5.8. Building Exterior Lighting

In the architectural exterior lighting restrictions, Shanghai aims to determine the scale and intensity of floodlighting, the scale relationship between objects of floodlighting and the surrounding environment, and the viewing range. The direction of light projection of the building's exterior lighting and the luminaires used should prevent glare and minimize light trespass. If the building facade is illuminated by floodlights, the direct luminous flux outside the illuminated surface should not exceed 25% of the total luminous flux of the fixture. Hospitals and residential buildings should not use floodlighting in outdoor spaces. Shanghai laws also provide maximum limit values for building surface brightness [23]. In addition, Guangzhou City has proposed nighttime lighting requirements for buildings, glass curtain wall buildings, and night illumination of the main part of buildings, hospitals, residential buildings, etc., with a surface material reflectance less than 0.2; floodlighting shall not be used. Floodlight luminaires shall not project the beam into the interior of the illuminated building. The spilled light beyond the illuminated area shall not exceed the design specifications of the urban nightscape lighting. The main part of buildings including hotels should be encouraged to adopt the illuminating night illumination method of façade floodlighting and to use internal light-transmissive lighting. The use of internal light-transmitting illumination should limit internal light transmission and ambient light brightness and color to prevent the light from being affected by the internal light [24]. Beijing offers a brightness limit for building facades [25]. No regulations have been enacted in Tianjin. Tables 14 and 15 show the maximum surface brightness of buildings in Shanghai and Beijing.

**Table 14.** Maximum surface brightness of buildings in Shanghai.


### **Table 15.** Maximum surface brightness of buildings in Beijing.


### 4.5.9. Greenbelt and Square Landscape Lighting

In green space and square landscape lighting, Shanghai proposed that a tree be irradiated from 3m to 5m, and a floodlight should be installed on the ground and not produce glare. Flowers should be illuminated from top to bottom, light sources containing wavelengths harmful to trees should be strictly limited around trees, and lighting time and intensity should be controlled for general trees. Lighting facilities should not be entangled or installed on trees for long periods of time and should not affect the growth of plants [23]. Guangzhou City proposed that glass curtain walls are forbidden to be installed in natural dark areas, such as nature reserves and forest parks [24]. Other regulations have not been raised. Similarly, Beijing and Tianjin did not propose relevant regulations.

### 4.5.10. Lighting of Rivers, Ponds, Fountains, and Other Water Bodies

Since rivers, bridges, ponds, fountains, and other bodies of water are commonly illuminated, Shanghai has proposed regulations for lighting rivers with seasonal or periodic water level changes. Lighting equipment on river banks and bridges must consider the effects of changes in the water level. Bridge floodlighting illuminates the upper and lower sides of the bridge deck. When the surface of the static water is arranged, the glare of the light source of the lightbox should be avoided [23]. Other cities have not ye<sup>t</sup> established any such regulations.

### 4.5.11. Advertising, Signboards, Display Signage, and Logo Lighting

In advertising, signboards, display screens, and logo lighting, Shanghai limits self-illuminating billboards and surface brightness of signboards and displays and also gives a maximum for functional lighting of urban commercial areas, public event areas, stadiums, and other places. The maximum vertical illuminance value of nighttime lights (including self-illuminating advertisements, signboards, displays, signs, etc.) relative to the obstacle light is generated at the observer's eyes [23]. Guangzhou City proposed that, to set up a large electronic display of neon light-illuminating materials and video outdoor advertising facilities, its location, brightness, and operating time should meet the technical specifications and light environment control requirements of the area [24]. There are no relevant regulations in Beijing and Tianjin. Tables 16 and 17 show the self-illuminating billboard, signboards, display screen, and logo surface brightness maximum limit and maximum vertical illumination of the interference light produced in Shanghai.

**Table 16.** Self-illuminating billboard, signboards, display screen, and logo surface brightness maximum limit value in Shanghai.


**Table 17.** The maximum vertical illumination of the interference light produced by self-illuminating billboards, signboards, display screens, and logos at the height of the human eye in Shanghai.


4.5.12. Limits and Measurement Methods of Maximum Visible Brightness for Light Emitting Diode (LED) Displays in Public Places

Shanghai has a limit for the maximum visible brightness of outdoor LED displays when the outdoor natural environment illumination is not more than 200lx (when the outdoor natural environment illumination is greater than 200lx, there is no limit to the maximum visible brightness of LED displays).

The maximum visible brightness of the indoor LED display is limited when the screen environment illumination is not more than 400lx (when the ambient illumination of the screen is greater than 400lx, there is no limit to the maximum visible brightness of the LED display).

The selection of test points was proposed in Shanghai using the measurement method. The test should be performed at multiple points suitable for viewing the display screen or possibly a ffecting the crowd. The measurement results can be listed or considered as the maximum value.

The measurement of natural environment illuminance was applied to the outdoor screen smoothly, and the position with only natural light outside the room was selected. The horizontal illuminance at 1.5 m from the ground was the natural ambient illuminance of the test site.

The illumination of the ambient environment of the screen was determined by selecting at least four points as close as possible to the periphery of the display screen, measuring the incident illuminance in the normal direction of the screen at each point, and calculating the arithmetic mean to illuminate the ambient environment around the display screen.

In the measurement step, there are four steps: 1. Determine that the running status of the LED display and the displayed image signal are the same as when the display is actually running. 2. Measure the relevant ambient illuminance with an illuminometer and record the ambient illuminance conditions. 3. In the visible range of the LED display audience, select the test point where you may observe the peak brightness of the screen, the position of the test point is extremely high, and the LED screen is tested at this position. 4. In a certain period of time, use the luminance meter to capture the peak brightness on the LED display and record it as L (i). In the measurement of brightness, the optical probe should not collect less than 16 adjacent pixels. You can select N test points and repeat the steps noted above. The luminance peak value L (i) of one test point is obtained (i: 1 ~ N). Then, the maximum visible brightness of the LED display is the maximum value Lmax among the brightness peaks of the N test points [27].

Guangzhou utilizes several outdoor advertising and signboard managemen<sup>t</sup> methods. In the fourth paragraph of Article 12, lighting of advertisements and signs in the form of LED outdoor electronic displays is prohibited from 22:30 to 7:30 the next day. Similarly, Guangzhou light radiation environment managemen<sup>t</sup> specifications (draft for comment) Article 33 proposes that outdoor advertising and signs set up in the form of LED outdoor electronic displays are prohibited from 22:30 to 7:30 at night, except airport and train display screens that announce information on stations, bus stops, etc. Guangzhou City only controls the timing of lighting, and there is no objective limit to lighting [28]. Tianjin and

Beijing have not put any regulations on LEDs. Tables 18 and 19 show the maximum visible brightness of outdoor and indoor LED displays in Shanghai.


**Table 18.** Limit of the maximum visible brightness of outdoor LED displays in Shanghai.


