SUSTAINABLE SITES: Light Pollution Reduction (SSc80) Credit Interpretation Request (Registered under NC 2.1 but submitting this credit under NC 2.2 through LEED Online) Our project is the new construction of a 47,000 ft2 4-story recreation/office building to serve as a community center for the Washington, DC Parks and Recreation Department. The program consists of an indoor gymnasium and stage, multipurpose room, offices, classrooms, weight and exercise room, and locker room facilities. The property sits at the intersection of two streets in the Columbia Heights neighborhood, and the building hugs the property line so that there is a "zero-property line" condition along the street corner. Across the street to the north of the property are high-density residential properties and across the street to the west are diplomatic buildings. To the east of our site boundary is a park with a playground and basketball court owned by DC Parks and Recreation. The southern boundary is bounded by a multi level apartment. The city street lights along the block are cobraheads, so there is significant ambient lighting. These are pre-existing fixtures that are not part of the scope of this project. We have determined that the site qualifies as LZ3 - Medium (Commercial/Industrial, High-Density Residential) Environmental Zone. We are requesting an interpretation for the requirement to design exterior lighting so that all site and building mounted luminaires produce a maximum initial illuminance value no greater than 0.20 horizontal and vertical footcandles at the site boundary or in this case the curbline, and no greater than 0.01 horizontal footcandles 15 feet beyond the site. Our lighting design currently meets all other requirements of this credit. However, there are 2 areas on the north side of the site where the horizontal and vertical illuminance values are between 0.20 and 0.30 for about 10 feet along the curb line that meets public streets, but they do drop to less than 0.01 footcandles 15feet beyond the curb line. These areas correspond to locations where exit doors exist. In these locations, fixtures are being provided to meet illumination requirements set forth by the National Fire Protection Association (NFPA) code NFPA 101 - Life Safety Code Chapter 7 for means of egress. Their requirement is to provide a minimum illumination on walking surfaces of 1 footcandle for exit passageways leading to a public way. The fixture being used is a wide throw fixture with a 26 watt compact fluorescent lamp that produces 1800 initial total lumens all emitted at an angle less than 90 degrees. These fixtures illuminate the side walk to the required 1 footcandle. The curb line for the street that is well lit by cobraheads is only 3.5ft from the sidewalk. Thus, the 0.30 footcandles at the curb line will be nothing in comparison to the light emitted by the streetlights. Illuminating Engineering Society of North America (IESNA) RP-33-99 describes light trespass to fit into one of two categories: - Adjacent property receives unwanted light (high illuminance levels) - Excessive brightness occurs in the normal field of vision (nuisance glare) In this case we believe that neither of these conditions exists. Do you agree that this design meets LEED\'s intent to reduce light pollution by minimizing light trespass while still upholding current design practices and meeting code requirements?