The lighting for urban exterior areas and buildings must be “community-responsive,” The design must be accepted by the residents, neighbors and the community. The IESNA recommends the following steps in the design process:
- Examine the community’s architectural theme to help establish a local identity. Examples are “entertainment and excitement”, or “stately, quiet and intimate.”
- Determine local and community lighting ordinances. These are standards that address light pollution, light trespass, min./max. illuminance levels, and which will affect the lighting design.
- Identify the surrounding brightness. These surrounds are classified as dark, medium and bright. Parks and residential neighborhoods are examples of dark surrounds. Bright surrounds are downtown metropolitan areas and industrial parks.
- Identify the neighboring areas and calculate the luminance of adjacent roadways, walkways and properties. This will help define luminance ratios that are suitable to the activity taking place in the area being lighted. A ration of 1:2 will allow the lighted area to blend in with the surround. A ratio of 1:10 will result in the lighted area being highly accented. However, exceeding a 1:10 ratio may cause distraction for motorists just as floodlighting a residential property at that ratio would result in complaints from the neighbors.
The lighting design must also be “energy-responsive”.
- Save energy by choosing the highest efficacy lamps and ballasts like SYLVANIA METALARC® POWERBALL® Ceramic Metal Halide lamps and precisely matched QUICKTRONIC® MH Series electronic HID ballasts.
- Select luminaires and lamps that place the light only where it is needed and at the right illuminance levels, to further reduce energy consumption.
- Introduce lighting control systems when appropriate. Illumination levels can be reduced or lighting systems can be selectively or completely shut off during unoccupied or late night periods to save even more energy and observe local lighting ordinances.