CS-2009 SSc8: Light Pollution Reduction 1 point

This project is located in a downtown area with a fair amount of ambient brightness. For a portion of the site, the design team desires to uplight a grove of trees immediately adjacent to the building and some other trees intermittently along one of the main paths through the site. The lights will be narrow or medium floods that keep the lumens below the canopy to fewer than 3500 lumens.As noted in the LEED Credit Ruling dated 3/14/03, some uplighting is allowed as long as the project adheres to all of the other conditions stated in that Credit Ruling.The project will be able to demonstrate that all other Light Pollution Reduction Credit requirements are met, including (1) full cut off luminaires for lamps over 3500 initial lumens and shielding for those over 1000 initial lumens. (2)Use of lighting controls to turn off lighting after hours and/or during post curfew periods. (3) Commissioning of lighting controls .The design team is anticipating minimal use of the uplighting and is setting our curfew for those luminaires at 8:00pm Standard Time and by 10:00pm during Daylight savings time. In addition there may be special events in which the uplighting remains on beyond the curfew specified above. The design team is proposing this schedule, but would be amenable to another schedule if the Credit Ruling Committee deemed one to be more appropriate.Please confirm that this schedule and approach are consistent with the USGBC\'s previous credit ruling on this subject.

Our current project is approximately a 75,000 sf student dormitory. The alternate compliance path (Option 2)states that light fixtures are to be automatically controlled and programmed to turn off following regular business hours. Since this a dormitory, regular business hours would not apply. The current design calls for digital timers and occupancy sensors in spaces accessible to students which include lounges, studies, corridors, and trash rooms. Digital timers have a on/off manual override, and the occ sensors have a switch upstream for manual override off, occ sensor on. Additionally, each floor will have a RA for "lights out." Please indicate if the current design scope would comply with Option 2 with these considerations.

Our project is a new 320,000 s.f. mixed-use project being designed and constructed to achieve various LEED NC 2.2 credits. The mixed use components consist of residential units, residential parking and commercial tenant space located in the bay area. The development is surrounded on all four sides by existing mixed use, commercial, retail and high density residential developments. The property sits at the intersection of two streets, and the building hugs the property line so that there is a "zero-property line" condition along the street corner. 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 it meets the intent of this credit in all areas except at the egress areas which are at levels required by code. 1) The proposed mixed use high density residential project is to be built from property line to property line and all of the exterior building lighting is provided for safety and comfort of the project and all of the lighting is part of the emergency egress pathway and is on emergency back up power. The values in the egress areas are as required by code and are the desirable levels for the safety of the occupants. 2) Because of the proximity of the property and/or curb line the max initial (and maintained) illimunance value will be greater than the .20 horizontal and vertical allowed levels to the site boundary. We are exceeding 1 foot-candle in most places, but it is all path of egress. 3) Because of the proximity to the site boundaries the .01 horizontal levels from the site boundary to 15 feet out will also be exceeded. Please confirm that this design meets the credit intent to reduce light pollution by minimizing light trespass while still upholding current design practices and meeting code requirements.

The credit guidelines to limit light trespass created by the building and site lighting being confined to the property is appropriate for most situations, but is incompatible with the requirements of transitional traffic zones that enter and exit the property and therefore generally located on the property line for most applications. The lighting provided at the property line for road entrance and exit locations serves a variety of purposes, namely: 1. The property area for the road crossing location is an area of potential pedestrian-vehicle conflict. This area requires an appropriate level of illumination for the safety of the pedestrians and for clear visibility of vehicle operators. 2. The area in question is an intersection. Illuminating Engineering Society of North America (IESNA) RP 8 (Standard Practice for Roadway Lighting) recommends that the illumination levels at vehicle conflict locations be increased above similar recommended roadway lighting levels. 3. Vehicle traffic will require a minimal amount of transitional lighting when leaving or entering a lit roadway. Variations in illumination have detrimental effects to the driver that increase the potential for an accident. 4. Provides awareness of vehicle traffic outside of the property to potential inflow of new vehicles. The particular application of this credit interpretation concerns a hospital emergency centre located in a downtown area with high traffic and pedestrian volumes. The site includes a surface parking area for emergency response and public vehicle traffic responding to the emergency centre. Individuals entering the property will often be unfamiliar with the environment and will therefore require a degree of illumination that promotes an awareness of the surroundings allowing them to safely navigate the area. The lighting design for the facility takes into consideration recommended practices outlined in the LEED credit for reducing light pollution. All exterior luminaires are provided as full cut-off type with internal source shielding ensuring no direct illumination is provided above the horizontal plane to limit any spill lighting. With the exception of traffic conflict areas, the exterior lighting design has confined all illumination within the property boundaries. IESNA RP 8 item 3.6.2 states ".driveways serving high volume activities.should be illuminated similar to a major/major intersection." Item 3.6.4 states ".traffic conflict areas should be provided with illuminance values 50 percent higher than recommended for the street." Surrounding roadways would be classified as "collector" routes with "high" degrees of potential pedestrian conflict locations. Table 9 of IESNA RP 8 suggests that the average maintained illumination at the pavement level for this type of intersection be provided with 24.0/2.4 (lux/fc). This is significantly higher than the 6.0/0.6 (lux/fc) level requirement of LEED. The Lake Union District CIR (08/16/2003) addresses spill lighting from the property, but not specifically with respect to traffic intersection. The lighting levels provided at the traffic intersections located for our project design are provided more closely in compliance with IESNA RP 8 for recommended lighting levels at the traffic boundary locations. For our application, the spill lighting will be provided onto a roadway and no lighting will penetrate adjacent property windows. The levels dictated however are inadequate for the recommended lighting requirements of this application. For pedestrian safety, it is imperative to provide an appropriate level of illumination that meets the requirements of all involved. Without a re-evaluation of the lighting requirements of this credit, it will not be possible to provide for the recommended practice lighting levels for most projects at traffic congestion locations. It is requested that the LEED credit requirements allowing no light trespass at the property line be relaxed at traffic conflict locations and be more closely defined so as to allow the designer the ability to provide the appropriate lighting levels for these locations while meeting the intent of the credit.

The project site consists of an existing 2-story building undergoing major renovation, a new 5-story office tower, and a new 2-story link connecting the buildings. The property is located in an industrial zone (LZ3) of the city. The property is also within an area considered at elevated risk for crime and vandalism. The existing 2-story building is 5\' within the south property line. An adjacent building is located 5\' beyond the south property line. There are three conditions at this line where we require interpretation of light trespass requirements: 1.The easternmost 230\' of the shared boundary is a drainage swale, 10\' wide, between the buildings. The adjacent building has no windows facing this strip. The strip is not easily surveyed and our intent is to light this area so as to deter lurking. 2.The next segment of the boundary begins with an exit door from our client\'s building. The adjacent property has a security fence at this segment of the property line. This adds an outdoor portion to the path of egress that requires those exiting to travel 70\' west from the exit door until they clear the fence and reach a public way. Our intent is to meet path of egress lighting requirements for this segment. 3.The westernmost segment is a 100\' wide parking lot on the adjacent site. This lot belongs to the adjacent building owner and is leased by our client. This area has not been included in calculations for any other LEED credits. As the lot is not fully lit by the owner, our client seeks to continue their current practice of lighting the northern portion of the lot from their building. The existing lighting for the areas in question consists of seven HID cutoff fixtures equally spaced along the building at heights between 15\' and 25\'. We intend to replace all existing fixtures with 70 watt metal halide full cutoff fixtures. The fixtures will be on a photocell control to minimize usage. The new fixtures will have a wall grazing distribution to keep footcandle levels at the property line down to 3.3 fc maximum. The average is 1.59 fc along the property line between the buildings. Please provide guidance as to whether our lighting strategy will satisfy the intent of the credit in the context of the close property line proximity plus the egress and security lighting requirements. Also please clarify if the practice of lighting the leased parking lot on the neighboring property is acceptable. Aside from the above issues, the lighting of the lot would conform to the credit requirements.

Our project is being constructed for a division of the Department of Homeland Security. It has been requested that a pole be added to display an American flag. The client wishes the flag be flown 24 hours a day, which requires lighting per Federal Flag Code, Sec 2 a. There have been several previous credit interpretations and rulings mentioning uplighting for flags, but not one that directly addresses this issue. Our request is the following: Is it acceptable to utilize uplighting for the purpose of lighting the American flag at night?

Our project is located in the Lake Union District of Seattle, Washington and falls under the lighting category \'High Ambient Brightness.\' The project comprises a five-story building on a 0.58 acre site. The building is bordered by city streets and sidewalks, which are not part of our project site.All exterior lighting complies with the referenced IESNA Practice Manual for Exterior Environments. All interior and exterior lighting is designed such that "zero direct-beam illumination leaves the building site" with the following exception.The building directly abuts the site boundary (city sidewalks in front and alley way in back). As a result, the exterior light fixtures will direct some light onto this adjacent sidewalks and alley way. The current alley way has no exterior lighting. Please confirm that we comply with the intent of SS8 to eliminate light trespass from the building site.

Our project is a 238,000 SF brick manufacturing facility in Terre Haute, Indiana. The project consists of 5,000 SF of office space and 233,000 SF of manufacturing area, including extrusion, drying, and kiln equipment. The requirement for INTERIOR LIGHTING indicates "The angle of maximum candela from each interior luminaire as located in the building shall intersect opaque building interior surfaces and not exit out through the windows." This would indicate that light other than that emitted by the angle of maximum candela would be allowed to exit thru non-opaque surfaces. Our building design includes diffuse translucent panels along the perimeter walls which allow 40% transmission of light through them. The angle of maximum candela does intersect these translucent surfaces, but the light is diffused by the panels. Even at the angle of maximum candela, any interior light passing through to the exterior is substantially reduced. Please verify that this meets the intent of the credit by minimizing light trespass from the building.

The August Wilson Center for African Culture (AWC) is a new construction, performing arts facility located near the wide end of the Golden Triangle of downtown Pittsburgh. We are operating under LEED 2.1 for the project. Our building is situated on the property line for two (2) of its sides. In the case of the one of the two sides, our building faces a controlled alleyway, which is bordered by another building on the long axis, and gated on the two entries to the alley (gated card access controlled by our building). There are currently no lights mounted to the existing building, and since our building will now enclose this walkway, we have taken it on ourselves (both for emergency code reasons as well as safety reasons) to light this alley. Obviously we are lighting over our property line, but it is in a controlled, and energy efficient manner. Our fixture selection utilizes full cutoff CFL fixtures (26W) spaced 18ft OC. Optically these fixtures have a short forward throw (as the alley is only 8ft or 16ft wide, depending on location), and a wide lateral throw. Illumination values are an even, with a moderate maximum value of 5.5fc, and a minimum value of just over 0.6fc. The notion is that there is no way to light this space according to the letter of LEED. However, as it needs to be lit, we are following the principles that otherwise govern good LEED practice. Please advise.

This project is a 12,000 s.f. addition to an existing office building thereby meeting the size requirements for LEED-NC. The project is located on a 20-acre working farm in a semi-rural area of the township. It has been determined that it qualifies as Environmental Zone E2. The new building addition is attached on the westerly side of the existing office building where it is bordered by live stock pasture leading up to rail road tracks (west property line). The property area in front of the new building addition consists of a small parking lot expansion which sits behind another live stock pasture, bordered by a road (north property line). On the south side of the new building addition is an existing and expanded parking area and existing farm buildings. The new building addition sits 100 or more feet from the property line on every side of the site and its elevation is below grade level of the road it fronts on (northern property line). The small parking lot expansion in the front of the new building addition did not require any new lighting. There are three new 8\' poles with decorative fixtures that were selected to match the existing lighting on site. These three poles are located at the corners of the new building addition and on the edge of the back parking lot, next to existing farm buildings. They provide mostly downward directed light, but do not meet the cutoff or full cutoff classification. Based on the calculations done for these three fixtures (and some downlights located in the entrance canopies), there are many areas of the site with zero footcandles. No light comes anywhere near the property line, so light trespass is not an issue. The three light poles have 150W High Pressure Sodium decorative, post-top, luminaires. They emit approximately 30% of the fixture lumens above 90

Our project is an office building located in an area surrounded mostly by residential properties. The office building and site will comply with the Light Pollution Reduction credit. The firm that will occupy this office building works on many projects of a sensitive nature so security is a significant concern, both for employees arriving early or working after dark and for protection of the facility from intrusion. Is it acceptable to include motion-sensor activated lights that do not fall within the allowable site lighting wattage? These lights would be located in the immediate vicinity of the building and would only be enabled to turn on when other site lights are off. They would only remain on for a limited time following activation. If such motion-sensor activated lights are allowed, can they be excluded from the other requirements of this credit, property line illuminance and uplight components, since their purpose is only safety and security?

Our project is located at the instersection of two Class 1 Pedestrian Streets in Downtown Seattle. The neighborhood is zoned Downtown Mixed Commercial, allowing for a variety of uses. The project is an 11 story Research and Development facility programmed as operable 24 hours per day. Immediate neighbors include the Greyhound Bus Terminal, The West Precinct Seattle police Department Headquarters, Qwest Communications and, dirctly across the Street, surface parking. These are all active 24 hour operations and contribute to the neighborhood\'s high ambient light level. Considering these factors we have selected lighting for the building which maintains safety for pedestrians while being uniform and understated. along the alley deep shielded Ruud E8-F fixtures are installed at 8\' above the pavement at egress and service doors. On the two street facades at sidewalks, we have utilized Bega 7475MH surface washers mounted at 10\' - 12\' above the walking surface and aimed at the underside of the translucent overhead protection canopies. This provides an even wash of indirect light to the pedestrian walking surface while eliminating the escape of direct light. The fourth side of the building is against the adjacent structure and has no lighting. Three parking levels above street level have cut-off fixtures installed 20\' or more from the exterior walls, further shielded by aluminum screening at the exterior openings to the garage. Lobby lighting is limited to recessed cans, recessesed track and diffuse light from an internally lit large glass sculpture.Our project replaces a surface parking lot that included two unshielded pole area-lights and two 2-sided illuminated billboards. Light level measurements were not taken when these elements were operational so comparative data is not available.I feel that we have responded to both the neighborhood and the credit although the light trespass onto the alley and sidewalks ranges from 2 to 10 footcandles. However, the light trespass onto "adjacent properties" is less than 0.6 footcandles (or 6 lux).I would appreciate your view on this particular situation.

Our project is located in the heart of downtown Allentown PA and falls under the lighting category "High Ambient Brightness." The site comprises an eight storey building, approximately 140 in height above grade, and a plaza in front of that building. The plaza is bordered by city streets and sidewalks (not part of our project site), with city standard historic pole mounted fixtures. These fixtures are not cutoff fixtures and distribute light in a radial pattern towards the street, the sidewalk below, and towards the plaza. Our project\'s landscape lighting scheme is designed to balance the perceived brightness from these city street lighting fixtures by utilizing up-lit trees within the plaza as glowing objects that replace the need for additional pole mounted fixtures. Additionally, the plaza incorporates a fountain with up-lit water jets to enliven the plaza at night and add to the perception of the plaza as an occupied public space. Aside from the trees and fountain, all other plaza lighting, and the light levels eminating from the adjacent internally lit 140\' high building, are clearly within proscribed low-level light standards proscribed by the LEED 2.0 Rating System and its associated credit inquiries. We would like the USGBC to confirm that the up-lighting scheme for these plaza trees and fountain conforms to the revised lighting requirements specified in the LEED 2.1 Rating System and thus the general intent of this credit to eliminate light trespass, improve night sky access, and maintain a safe and appropriately lit urban public space.Beginning with the trees, which are the primary lighting component of the plaza, they are nominally 16\' to the top of the canopy. The illuminated undersides of the canopy at this pedestrian scale would significantly contribute to the public perception of a safe environment. Based on detailed computer modeling of the proposed tree lighting scheme, we find an average light level of 2.0 fc directly above the tree canopy when lit from below by the specified recessed up-lighting fixtures. As an additional note, the source is regressed within the fixture suspended from a cast iron tree grate cross louver providing superior cut off shielding of the source. Based on the foot candle levels above the tree canopy, and especially when put in the context of the adjacent street lights and the neighboring tall building, the lighting of these trees meets IESNA standards for low level exterior lighting and we believe that there is effectively no stray light adversely affecting this urban setting.The second area of up lighting in the plaza is the fountain, which comprises water jets that are lit from below by parabolic luminaries. The light fixtures are provided power only when the fountain pumps are active, so there would be no circumstance in which the lights would operate without a water column above the lamp to shield the light source. The effectiveness of the water as a light shield was determined in a measured study of the fountain light levels, which recorded an average light level of 9.06 fc three feet above the water feature when utilizing a 50W MR16 source. The design calls for a 35W lamp instead, which should reduce the measured average light level above the fountain to approximately 6fc. As a note, the luminaires are less than 3500 lumens and do not require full cutoff shielding; because each fixture is recessed well below the level of the paving, the full intensity of a lamp would never be visible since there will always be a column of water atop it. Accordingly, we believe the fountain lighting levels are well within the IESNA standards, especially as the fountain is located between the unshielded city street lights and the 140\' high illuminated building.Please confirm that these two plaza elements with their carefully shielded up-lit elements meet both the specific requirements of LEED 2.1 SS credit 8, and the larger intent "to provide enough illumination for safety, accessibility and public perception while at the same time avoiding unnecessary light pollution."

Our project is a 1.2 million SF science building renovation and expansion for an urban university campus. The program consists of research and teaching laboratories, lab support areas, offices, conference rooms, lecture halls, classrooms, libraries, food service, and public areas. Exterior light illumination levels have a significant impact on the overall safety of the staff and students in this building. We are requesting an interpretation of SS Cr. 8 requirements for pedestrian walkways within an urban university campus. We feel that pedestrian identification at a distance is critical for an urban campus setting. Therefore, we have used the category of Average Vertical Illuminance Levels for Special Pedestrian Security as listed in IESNA RP-33-99 Table 6: Recommended maintained Illuminance Levels for Pedestrian Ways. Using these criteria, (for walkways distant from roadways) our layout results in vertical illuminance at or below the IESNA recommendation of 0.5 foot candles. All efforts have been made to meet the SS Cr. 8 criteria. The open grassy areas between walkways are not lighted at night so the walkway lighting provides the majority of the lighting on the site. The site meets E4 zone criteria for light trespass and the design complies with SS Cr. 8 requirements. Luminaire selection meets all SS Cr. 8 LEED criteria with regard to shielding and Full Cutoff classification. We would like an interpretation of the SS Cr. 8 requirements with regard to our pedestrian walkways to confirm we can use the Average Vertical Illuminance Levels for Special Pedestrian Security category to show conformance.