To increase night sky access, improve nighttime visibility, and reduce the consequences of development for wildlife and people.
RequirementsMeet the Light Pollution Reduction requirements for the following:
- One option in Exterior Lighting for Residential Areas
- Exterior Lighting for Circulation Network
- Uplight and light trespass requirements in Exterior Lighting for All Other Areas
- Covenants, Conditions, and Restrictions.
Exterior lighting for residential areas
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. Projects may use different options for uplight and light trespass.
Option 1. BUG rating methodEach 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.
Option 2. Calculation methodMeet the requirements of Option 2 in Exterior Lighting for All Other Areas, below.
Exterior lighting for circulation networkFor 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.
Exterior lighting for all other areasUse 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.
Option 1. BUG rating methodDo 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.
Table 1. maximum uplight ratings for luminaires, by lighting zone
Option 2. Calculation methodDo not exceed the following maximum percentages of total lumens emitted above horizontal.
Table 2. Maximum percentage of lumens above horizontal, by lighting zone
Option 1. BUG Rating MethodDo 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.
Table 3. Maximum backlight and glare ratingsA 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:
- When the property line is adjacent to a public area that is a walkway, bikeway, plaza, or parking lot, the lighting boundary may be moved to 5 feet (1.5 meters) beyond the property line;
- When the property line is adjacent to a public street, alley, or transit corridor, the lighting boundary may be moved to the center line of that street, alley, or corridor;
- When there are additional properties owned by the same entity that are contiguous to the property, or properties, that the LEED project is within and have the same or higher MLO lighting zone designation as the LEED project, the lighting boundary may be expanded to include those properties.
Option 2. calculation methodDo 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.
Table 4. maximum vertical illuminance at lighting boundary, by lighting zoneFC = footcandle
Exemptions from uplight and light trespass requirementsThe following exterior lighting is exempt from the requirements, provided it is controlled separately from the nonexempt lighting:
- specialized signal, directional, and marker lighting for transportation;
- internally illuminated signage;
- lighting that is used solely for façade and landscape lighting in MLO lighting zones 3 and 4 and is automatically turned off from midnight until 6 a.m.;
- lighting that is integral to other equipment or instrumentation that has been installed by the equipment or instrumentation manufacturer;
- lighting for theatrical purposes for stage, film, and video performances;
- street lighting;
- hospital emergency departments, including associated helipads; and
- lighting for the national flag in MLO lighting zones 2, 3, or 4
Covenants, conditions, and restrictionsEstablish covenants, conditions, and restrictions (CC&R) or other binding documents that require continued adherence to the above requirements.
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