Discussion on Key Considerations in Park Night-Time Lighting Design

1 Introduction
With the advancement of urbanization in China, landscape greening has also experienced significant development, making the design of nighttime park lighting increasingly important.

II. Principles for the Arrangement of Landscape Lighting
The illumination requirements for roads and plazas within parks are significantly lower than those for indoor buildings. Specifically, for high-traffic pedestrian paths, the average pavement illuminance Eav shall be 10 lux, with a minimum illuminance Emin of 3 lux; for low-traffic vehicle lanes, the average pavement illuminance Eav shall be 5 lux, with a minimum illuminance Emin of 1 lux. For square areas, the typical illuminance is generally between 20 and 30 lux. Therefore, in park lighting design, it is essential to comply with regulatory requirements: lighting fixtures should not be arranged too densely, energy consumption should be minimized as much as possible, and the park’s landscape should feature strong contrasts between light and shadow to highlight key elements. Consequently, the rational placement of landscape lighting is a topic worthy of careful consideration.

The areas within the park that require lighting include park roads, the park entrance plaza, landscape ponds, large trees, landscape walls, and landscape features. The following section provides a categorized description of the lighting for each of these areas.

2.1 Road Lighting Design

Road lighting in the park is functional lighting and only needs to meet basic illuminance requirements.

Roads within the park are generally classified by width as 6 meters, 4 meters, 2.5 meters, and 2 meters. As a general rule, narrow paths 2 meters wide or less should be illuminated with lawn lights, while roads 2.5 meters wide or wider should be lit with courtyard streetlights.

The lighting design for the entrance plaza is often the focal point of a park’s landscape lighting. Prior to design, close collaboration with a professional landscape architect is essential to first determine whether the plaza is a sunken or non-sunken space. Typically, functional lighting for the plaza is provided by landscape light poles installed at intervals of about 20 meters within the surrounding green areas. If the plaza grid is small, additional luminaires in the center of the grid may be omitted; for larger grids, the specific lighting scheme should be tailored based on whether the plaza is sunken. In the case of a sunken plaza, step-side wall lights can be evenly distributed along the riser faces of the steps. These wall lights are generally circular recessed fixtures with a diameter of no more than 40 millimeters, spaced at regular intervals of approximately 3 meters. For non-sunken plazas, recessed decorative lights can be uniformly installed within the paving grid. The precise placement of these luminaires should be coordinated with the garden’s paving grid pattern: if the paving grid is square, luminaires may be positioned at the intersections of the grid lines; if the grid is rectangular or elongated, they can be placed at the center of each paving unit. Luminaires installed within the paving grid should be arranged in a regular, geometric pattern to enhance visual harmony, as illustrated in Figure 1.

2.3 Landscape Pond Lighting Design

Before commencing lighting design, it is essential to engage in thorough consultation with relevant professionals to determine which areas of the landscape pool require illumination and what specific lighting effects are desired. Specifically, do you need to illuminate the pool’s side walls, or the water surface? For instance, if the pool features sculptures or landscaped walls, should these be illuminated, and if so, from which direction? And if there is a fountain in the pool, does it also require lighting? Once these details are clearly understood, proceed with the specific design. Generally speaking, if the pool’s side walls need to be illuminated, wall-mounted fixtures should be installed along the walls; if the water surface is to be lit, underwater lights should be placed beneath the surface, securely mounted on brackets at the pool bottom—hidden installation is not recommended, as it would make maintenance difficult. The distance between the side-wall lights and the water surface should be less than 100 mm; otherwise, the light will struggle to penetrate the water, failing to achieve the desired illumination effect. For illuminating sculptures in the pool, underwater lights can be evenly arranged around the sculpture; for landscaping walls, LED underwater light strips can be installed at various points along the wall; and for fountains and small water features, underwater lights are typically strapped directly onto the nozzles. This approach offers superior results. In addition, special attention must be paid to pools without railings: decorative lights should be evenly distributed along the pool edge to ensure

It serves as a warning at night to prevent visitors from accidentally falling into the pool.

2.4 Landscape Lighting for Historic Buildings

The main historic structures within the garden include paifang archways, covered walkways, and pavilions; these will be discussed separately:
(1) Archway lighting: Ground-mounted recessed lights shall be installed at the base of the archway’s upright columns, and illuminated pole fixtures shall be arranged on both sides of the archway.
(2) Corridor lighting: Ceiling-mounted luminaires may be installed at the corridor ceiling (for wood or concrete structures); wall-mounted luminaires may be installed on columns (except when the columns are made of wood); recessed decorative ground lights (with integrated seating) may also be provided; however, such installations should not be excessive. If the corridor ceiling requires illumination, LED strip lights may be installed along the outer edge of the corridor.
(3) Exhibition Hall Lighting: Floodlighting may be evenly arranged along the top perimeter of the exhibition hall; no lighting is provided inside the hall.

2.5 Layout Principles for Other Landscape Lighting Fixtures
(1) Tree Lighting (LOGO Stone Lights): Use ground-mounted lights when trees and LOGO stones are installed in green spaces; use in-ground lights when trees and LOGO stones are installed on sidewalks.
(2) Wall lights: Ground-mounted lights or LED wall-washing light strips may be used for illumination.
(3) Flower beds and tree surrounds: Wall lights can be evenly arranged along one side of the flower beds and tree surrounds.
(4) Lighting for wooden boardwalks: First, determine whether the boardwalk is elevated above ground level. If it is, install landscape lighting poles along the boardwalk; if the boardwalk is at or below ground level, embed decorative lights on one side of the boardwalk.
(5) Lighting for flower racks: Wall-mounted sconces or in-ground decorative lights may be used. If there are seating areas beneath the flower rack, in-ground decorative lights should not be installed directly beneath the seats.
(6) Bridge Deck Lighting: For bridges with a deck length of less than 6 meters, no lighting fixtures are required on the bridge deck; illumination may be provided solely by installing courtyard lights at both ends of the bridge approach.

When the bridge length is approximately 30 meters, lighting fixtures should be considered for installation on the bridge structure. If the bridge railing is made of concrete, wall-mounted luminaires can be installed on the railing; if the railing is made of stone, LED floor tile light strips can be installed on the bridge deck on both sides.

2.6 Use of Solar Lights

Solar-powered lighting offers energy-saving and environmentally friendly benefits, but it is relatively expensive and has low luminous efficacy. Therefore, its use should be carefully considered in light of the specific site conditions. Solar streetlights are most suitable for areas where the park is located far from the substation, making grid power supply difficult, or where cable installation is challenging in mountainous regions. In other locations, solar lighting should be used with caution; otherwise, not only will the intended energy-saving goals fail to be achieved, but unnecessary waste may also result.