To increase night sky access, improve nighttime visibility, and reduce the consequences of development for wildlife and people.
Meet the Light Pollution Reduction requirements for the following:
Divide the project into model lighting ordinance (MLO) lighting zones LZ0 to LZ4 based on site-specific characteristics using the definitions of lighting zones provided in the Illuminating Engineering Society and International Dark Sky Association (IES/IDA) MLO User Guide.
Meet the requirements below for each lighting zone within the project.
Meet either Option 1 or Option 2 for all exterior lighting in new residential construction and residential buildings undergoing major renovations. Existing residential construction is exempt.
Option 1. BUG rating method
Each fixture must have a backlight-uplight-glare (BUG) rating (as defined in IES TM-15-11, Addendum A) of no more than B2-U2-G2.
Meet the requirements of Option 2 in Exterior Lighting for All Other Areas, below.
For any portions of the circulation network not governed by national, state, or other superseding regulations, do not install street lighting unless conditions warrant the need for street lighting.
New and existing street lighting luminaires must not emit any light above 90 degrees (horizontal), based on the photometric characteristics of each luminaire when mounted in the same orientation and tilt as specified in the project design or as currently installed.
Exception for ornamental luminaires: Using the lowest MLO lighting zone for immediately adjacent properties, meet the requirements of the IES/IDA MLO, Table H.
Use either the BUG method (Option 1) or the calculation method (Option 2) to meet uplight and light trespass requirements. Projects may use different options for uplight and light trespass.
Do not exceed the following luminaire uplight ratings, based on the specific light source installed in the luminaire, as defined in IES TM-15-11, Addendum A.
Do not exceed the following maximum percentages of total lumens emitted above horizontal.
Do not exceed the following luminaire backlight and glare ratings (based on the specific light source installed in the luminaire) as defined in IES TM-15-11, Addendum A, based on the mounting location and distance from the lighting boundary.
A lighting boundary (or boundaries) is defined as the perimeter of each lighting zone within the project boundary. A lighting boundary can be modified under the following conditions:
Orient all luminaires less than two mounting heights from the lighting boundary such that the backlight points toward the nearest lighting boundary line. Building-mounted luminaires with the backlight oriented toward the building are exempt from the backlight rating requirement
Do not exceed the following vertical illuminances at the lighting boundary of each lighting zone in the project (use the definition of lighting boundary in Option 1). Calculation points may be no more than 5 feet (1.5 meters) apart. Vertical illuminances must be calculated on vertical planes running parallel to the lighting boundary, with the normal to each plane oriented toward the property and perpendicular to the lighting boundary, extending from grade level to 33 feet (10 meters) above the height of the highest luminaire.
FC = footcandle
The following exterior lighting is exempt from the requirements, provided it is controlled separately from the nonexempt lighting:
Establish covenants, conditions, and restrictions (CC&R) or other binding documents that require continued adherence to the above requirements.
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