NIGHT SKY AND DARK ENVIRONMENTS: BEST MANAGEMENT PRACTICES FOR ARTIFICIAL LIGHT AT NIGHT ON BLM-MANAGED LANDS TECHNICAL NOTE 457 43 Table 1. Descriptions of lighting zone performance standards according to the IDA-IES Model Lighting Ordinance (IDA-IES 2011). Lighting Zone Recommended Performance Standard Notes LZ0 No ambient lighting Areas where the natural environment will be seriously and adversely affected by lighting. Impacts include disturbing the biological cycles of flora and fauna and/or detracting from human enjoyment and appreciation of the natural environment. The vision of human residents and users is adapted to the darkness, and they expect to see little or no lighting. When not needed, lighting should be extinguished. Lighting zone 0 applies to areas where permanent lighting is not expected and, when used, is limited in the amount of lighting and the period of operation. LZ0 typically includes undeveloped areas of open space, wilderness areas and preserves, areas near astronomical observatories, or any other area where the protection of a dark environment is critical. Special review may be appropriate for any permanent lighting in this zone. LZ1 Low ambient lighting Areas where lighting might adversely affect flora and fauna or disturb the character of the area. The vision of human residents and users is adapted to low light levels. Lighting may be used for safety and convenience, but it is not necessarily uniform or continuous. Most lighting should be extinguished or reduced as activity levels decline. Lighting zone 1 pertains to areas where low ambient lighting levels are appropriate. These typically include administrative facilities and other commercial or industrial/storage areas typically with limited nighttime activity. May also include the developed areas in recreation and other natural settings. LZ2 Moderate ambient lighting Areas of human activity where the vision of human users is adapted to moderate light levels. Lighting may typically be used for safety and convenience, but it is not necessarily uniform or continuous. Lighting may be extinguished or reduced as activity levels decline. Lighting zone 2 pertains to areas with moderate ambient lighting levels. These typically include industrial facilities in an area otherwise zoned LZ0 or LZ1.
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