Entry Type ID Date Applicable Rating System Primary Credit Inquiry (LIs) Ruling (LIs) Related Addenda/LIs Related Resources Campus Applicable Internationally Applicable Country Applicability Reference Guide (Addenda) Page (Addenda) Location (Addenda) Description of Change (Addenda) "LEED Interpretation" "10114" "2011-11-01" "New Construction, Existing Buildings, Core and Shell, Schools - New Construction, Retail - Commercial Interiors, Healthcare, Neighborhood Development" "SSc8 - Light pollution reduction" "Can projects use the actual Property Boundary/ Property Line rather than the LEED Project Boundary (if the LEED Project Boundary is smaller than the Property Line) for the light trespass aspects of this credit? If so, are other aspects of exterior lighting (covered by this credit) to be evaluated relative to the LEED Project Boundary or Property Line if a project elects to use the Property line rather than the LEED Project Boundary for trespass criteria? " "If the LEED Project Boundary is smaller than the property line, projects can use the property line (property boundary) of their property to meet the requirements of this credit. If the light trespass requirements are met at the property line, the other aspects of the exterior lighting requirements must also be met at the property line.\n\nFor properties that contain sensitive areas (such as sleeping units or species habitats), the project must meet the exterior lighting requirements at the boundary of the sensitive area. An area is considered sensitive if it has a lower lighting zone designation than adjacent areas. If there are any parcels within the property that have a lower lighting zone designation, the exterior lighting requirements must be met at the lighting boundary of those areas.\n\nDefinition of ""Lighting boundary"": the lighting boundary is located at the property line or boundary of the LEED project. This boundary may be expanded to include any additional properties owned by the same entity that are (1) contiguous to the project property and (2) have the same or higher Model Lighting Ordinance Lighting Zone designation as the LEED project.\nExceptions:\n When the property line abuts a public area that is a walkway, bikeway, plaza, or parking lot, the lighting boundary extends to 5 feet beyond the property line; \n When the property line abuts a public roadway or public transit corridor, the lighting boundary extends to the centerline of that roadway or corridor. \n\nApplicable Internationally\n\n***Update 1/1/13: LI 10114 has been superseded by LI 10236. 10114 is no longer valid." "3122, 10236" "None" "X" "LEED Interpretation" "10147" "2012-04-01" "New Construction, Core and Shell, Existing Buildings, Neighborhood Development" "SSc8 - Light pollution reduction" "Can multifamily projects be exempt from the interior lighting requirements?" "Yes, multifamily LEED projects are exempt from the Interior Lighting requirements of this credit. Residential spaces (dwelling units only) within the scope of other LEED projects are also exempt from the Interior Lighting requirements. Item #3 in LEED Interpretation #5149 (""[3] Residential spaces may not be exempted from the interior lighting requirements."") is now void." "5149" "None" "LEED Interpretation" "10236" "2012-10-01" "New Construction, Core and Shell, Schools - New Construction, Healthcare, Retail - Commercial Interiors, Neighborhood Development plan, Neighborhood Development" "SSc8 - Light pollution reduction" "Can light trespass extend beyond the LEED Project Boundary if the adjacent land is owned by the project owner? Can projects use the actual property boundary/property line rather than the LEED Project Boundary (if the LEED Project Boundary is smaller than the property line) for the light trespass aspects of this credit? Can the lighting boundary be used in place of the LEED Project Boundary or site boundary for the purposes of this credit? When can the lighting boundary be modified? Can campus projects use the campus boundary for this credit? Do all SSc8 credit exterior requirements need to met at the lighting boundary? Does street lighting need to be included? How is the lighting zone determined when the project contains, or is adjacent to, a sensitive area?" "All instances in the credit language of ""LEED project boundary"" or ""site boundary"" shall be considered to refer to the ""lighting boundary"", for the purposes of this credit only. The lighting boundary is located at the property lines of the property, or properties, that the LEED project occupies. The lighting boundary can be modified under the following conditions:\n-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. \n-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. \n-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 lighting zone designation as the LEED project, the lighting boundary may be expanded to include those properties. \n\nIf the LEED project boundary is smaller than the property line, projects can use the lighting boundary to meet the light trespass requirements of this credit. Buildings that are part of campuses or shared properties can use the ""campus boundary"", i.e. the campus property line, to comply with the light trespass requirements of this credit. All LEED projects attempting SSc8 should continue to meet all exterior requirements (LPD, uplight, trespass) based all of the exterior luminaries within the LEED project boundary. The lighting boundary is only for the purposes of the trespass calculation, based on the light emitted by the luminaires within the LEED project boundary. Project teams should take note that the LEED project boundary must be appropriately defined and comply with Minimum Program Requirement (MPR) #3- ""Must be a reasonable site boundary"".\n\n Street lighting that is required by governmental authorities to be installed within the LEED project, specifically for the purposes of lighting a public street, does not need to be included in any of the calculations. Project teams should provide documentation of the government requirement and a narrative describing the application of this exemption to the project.\n\n Determination of the appropriate lighting zone is critical for this credit. For properties that contain sensitive areas (such as sleeping units or species habitats), the project must meet the light trespass requirements at the boundary of the sensitive area. An area is considered sensitive if it has a lower lighting zone designation than adjacent areas. If there are any parcels within the property that have a lower lighting zone designation, the exterior lighting requirements must be met at the lighting boundary of those areas.\n\n Applicable Internationally. \n\n***Update 1/1/13:This interpretation is written in an attempt to clarify the number of questions and ambiguities that exist around the \'lighting boundary\'. This interpretation supersedes LI 1622, LI 2342, LI 5272 and LI 10114\n\n **Update 4/2/2014 strictly for Neighborhood Development projects:\n Only the following portion of this ruling was made applicable to Neighborhood Development projects: ""Street lighting that is required by governmental authorities to be installed within the LEED project, specifically for the purposes of lighting a public street, does not need to be included in any of the calculations. Project teams should provide documentation of the government requirement and a narrative describing the application of this exemption to the project.""" "10114, 2342, 3108, 5016, 5188, 5272, 5753, 1622, 1649, 2319" "None" "X" "LEED Interpretation" "10262" "2013-01-01" "Core and Shell, New Construction, Schools - New Construction, Retail - Commercial Interiors, Healthcare" "SSc8 - Light pollution reduction" "Does a reduction in the total LPD for exterior lighting warrant an exemption from the reduced uplighting requirements?" "The exterior lighting power density (LPD) and uplighting requirements for SSc8 should be met in their entirety. In order to achieve the credit, project teams should comply with the LPD and the uplighting requirements independently. Substantial reduction in the percentage of total allowable LPD for exterior lighting does not compensate for, or warrant, an exemption from the reduced uplighting requirement for each zone. The purpose of reducing the uplight is to limit the amount of light emitted at an angle of 90 degrees or higher from nadir (straight down). Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1482" "2006-05-16" "New Construction" "SSc8 - Light pollution reduction" "Our project is a 1.2 million SF Medical 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. There are two adjacent major urban hospitals and no adjacent residential neighborhoods. This medical science building and all the adjacent hospital facilities in this area are 24 hour operations. The street lights along the block are cobraheads so there is a significant ambient light level. We are requesting an interpretation for the selection of the exterior luminaires for pedestrian walkways and plaza areas. The intent of SS Cr. 8 v2.1 states ""Eliminate light trespass from the building and site, improve night sky access and reduce development impact on nocturnal environments."" The credit requires luminaires with more than 3500 initial lamp lumens to meet the Full Cutoff Classification. It also requires zero light to cross project or real campus property boundaries and zero uplight. Due to the high ambient light levels in the vicinity of the site, we are requesting a variance to use a luminaire with a small amount of uplight. This luminaire meets the requirements of other current industry standards where environmental zone is taken into effect with respect to light pollution. Within this setting, current industry standards would allow ""up to 5% of the total initial designed fixture lumens above 90 degrees"" and ""a maximum initial illuminance value of no greater that 0.20 horizontal and vertical footcandles at the site boundary and must drop off to 0.01 footcandles within 15 feet beyond the site"". The luminaire we are requesting to use is classified as Cutoff and has only 0.5% initial lamp lumens and 1.2% of the total initial designed fixture lumens above 90 degrees from nadir. The luminaire provides no direct glare. Additionally, this luminaire has been selected to be the new Campus Exterior Lighting Standard (meeting the newer LEED NC v2.2 for this credit). All future campus projects will use this fixture. The University desires to use it for this v2.1 project at this time. The use of this one luminaire across the campus offers benefits of sustainability with respect to maintenance practices by reducing the quantity of spare fixtures, components and lamps needed. It also provides campus design continuity in their open spaces." "The project is located within an urban campus in an area of high ambient brightness. Fixtures selected for the site, as a part of the campus standard, are classified as cutoff fixtures with 1.2% of the total fixture lumens being emitted above 90 degrees from nadir. It is assumed from the submitted narrative that these fixtures exceed 3,500 initial lamp lumens, which would require them to be full-cutoff in order to meet the requirements of this credit. The narrative notes that these fixtures have been selected by the campus to comply with the requirements set forth under LEED-NC v2.2 and are requesting that this fixture be allowed for this specific case. Although the fixture does not meet the specific requirements of v2.1, the context in which it is being used appears to meet the intent of this credit. In order to demonstrate compliance with the credit\'s intent, the project team should submit detailed documents, including a photometric report for the specific luminaire, to illustrate the ambient site conditions and to confirm that the overall site illumination design and fixture selection meets the intent of this credit. It may also be beneficial for the project team to explore the use of NC v2.2 for the overall project submittal. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "1588" "2006-10-02" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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" "The applicant is requesting guidance for the lighting of specific existing site conditions with non-compliant lighting and high lighting levels. 1. All light fixtures with initial lumen output greater than 3500 lumen must meet the full cutoff requirements as per page 69 of the LEED-NC v2.1 Reference Guide in order to meet credit requirements. 2. Based on the narrative, it appears the project will be able to demonstrate that there is no light trespass beyond the project site boundary and that the lighting at the property line will meet the requirements of Table 1 on pg. 70 of the reference guide. 3. IESNA RP-33 -99 refers to IESNA RP-20 Lighting for Parking Facilities to determine maximum to minimum ratios (\'Max-to-Min Ratio\') for parking lot lighting. Lighting levels beyond the parking area do not need to be considered in the calculations. Using RP-33 Table 1 recommendations for ""Basic"" illuminance, there shall be 0.2 minimum maintained footcandles in the parking lot and the Uniformity Ratio shall be no more than 20:1. In summary, your current proposal will not meet the requirements of this credit. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1622" "2006-12-02" "New Construction, Core and Shell, Schools - New Construction, Retail - Commercial Interiors, Healthcare" "SSc8 - Light pollution reduction" "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 Lake Union District CIR (8/16/2003) was intended to light alleyways, not streets, and is not appropriate for this CIR. Because this site abuts a public right of way, the 6 lux (0.6 fc) requirement may be met relative to the curb line instead of the site boundary, and drop to 0.01 fc (0.1 lux) 15 feet past the curb line per LEED v2.2 SSc8 requirements. The determination of the lighting zone takes into account the nature of surrounding properties and sets the light trespass limit given the overall ambient brightness.\n\n***Update 1/1/13: LI 1622 has been superseded by LI 10236. 1622 is no longer valid." "10236" "None" "LEED Interpretation" "1649" "2006-12-15" "New Construction, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "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?" "The proposed strategy for meeting the intent of the credit is acceptable given the context and adjacencies of your project. Two spaces are slightly over the maximum illuminance values at the site boundary, but these spaces are incompliance at 15 feet beyond the boundary. Given the other lighting adjacencies in those areas and the fact that the project complies with all other criteria, the intent of the credit is being met." "10236" "None" "LEED Interpretation" "1724" "2007-03-23" "New Construction, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "The project is a four-story, 60,000 SF, speculative office building that is being submitted under LEED-CS. As we understand the intent, Credit SS8 - Light Pollution Reduction, aims to reduce light pollution through the control of interior lighting, exterior light distribution, and exterior lighting power density. Our question concerns the calculation requirements for the exterior lighting power density. We have been very diligent about reducing the overall lighting power density across the site. The site lighting has a 47% reduction of light power density as compared with the allowable light power density in ASHRAE 90.1.2004. All of our exterior site lighting is on a photocell/master time control system that turns off all non-emergency lights at 10pm. Because of the neighboring uses, we have voluntarily eliminated all building façade lighting on the western façade, which accounts for nearly a third of the total building façade. This allows us to focus our façade lighting on the public face of the building, adjacent to walkways, parking, etc.. Based on our total façade area (including the western façade) our lighting power density meets the credit requirement of 0.1 watts/SF. ASHRAE, however, calculates the LPD for each illuminated façade. Using this methodology, our LPD is 0.16 watts/SF, which is a 20% reduction from the ASHRAE standard. Does this meet the intent of the credit?" "The CIR is inquiring if projects can combine the lighting power densities for all building façade lighting when calculating compliance for this credit. Per the referenced ASHRAE Standard, building façades must be calculated individually and are considered non-tradable (cannot be traded between surfaces or with other exterior lighting areas.) In order to demonstrate compliance with the requirements of this credit, projects must document a minimum 50% LPD reduction from the ASHRAE Standard Allowable LPD for building façade and landscape lighting for each individual illuminated façade. Additionally, the intent of the credit is to minimize the amount and overall intensity of installed site lighting to increase night sky access. Increasing the lighting intensity on one façade above the minimum requirements, although other facades are non-illuminated does not meet the intent of this credit. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1956" "2007-12-18" "New Construction, Existing Buildings, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "The project is a four level public parking ramp that is an independent building from but serves several floors of condominiums and a 24 hour operated casino, which makes the parking ramp a 24 hour occupied structure. There are no exterior walls on the ramp with the exception of floor to ceiling structural columns on a 24\' by 56\' grid. The fixtures are mounted at 11\' above the finished floor and placed within 10\' of the edge of the decks with a glare shield to reduce light spill out from the ramp. The LEED interior lighting requirements state that ""The angle of maximum candela for each interior luminaire as located in the building shall intersect opaque building interior surfaces and not exit out through the windows."" We have no windows on the parking structure and no other way to prevent light from escaping from the structure on the sides where it does not directly abut another building. We are asking for an interpretation as to whether this is considered an interior or an exterior lighting application? A ruling will help us determine if we will be able to pursue a LEED credit for light pollution reduction on this project." "The applicant is seeking clarification as to the interior/exterior area classification for a four level open air parking ramp building. For the purposes of SSc8, parking structure covered floor area is to be considered interior area and uncovered area is to be considered exterior area. Thus, any lighting within covered area must meet the interior lighting requirements of this credit and any lighting within uncovered area must meet the exterior lighting requirements of this credit, including being below specified foot candles horizontal and vertical at all locations outside the boundary of the property. For the purposes of clarity, the credit requirements pertaining to interior luminaires\' angle of maximum candela not exiting out windows also requires that interior luminaires\' angle of maximum candela not exit out building openings or other translucent surfaces. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2051" "2008-02-27" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "Because the criteria for Sustainable Sites Credit 8 have changed substantially from LEED-NC version 2.1 and version 2.2, this Credit Interpretation Request seeks guidance on whether CIRs issued for v2.1 would apply to similar situations under v2.2. The Tacoma Center for Urban Waters (TCUW) is a new 56,000 square foot office and laboratory building, located on the east side of the Thea Foss waterway in an area currently occupied by industrial uses. The ambient light level of this area is not high due to the fact that very little night use occurs. The TCUW will include facilities that are available to community groups and it is anticipated that a fair amount of after-hours use will take place. In addition, security for TCUW staff is a concern even during normal operating hours, as the Tacoma area experiences very short days during the winter months and it is anticipated that staff will arrive and leave in darkness for a significant part of the year. We have determined that the site qualifies as LZ3 - Medium (Commercial/Industrial, High-Density Residential) based on the current use of the surrounding area as well as the proposed use by TCUW. We would like to confirm that uplights which are shielded (i.e., located under an opaque canopy) would not count toward the percentage of allowable uplight under v2.2. We would also like to confirm that the principle outlined in the Columbia Heights CIR (12/1/2006) would apply to the TCUW project. The project includes a portion of the building that is set back from the property line by only 5 feet. The adjacent property is a narrow strip between our project and the city street that is used to park tanker trucks for the adjacent industrial uses. Our lighting of this area addresses two concerns. The first is security in this area, which does not receive any significant ambient lighting from surrounding properties or the street. Because views to the street are often blocked by parked trucks, the feeling of security in this area is very important. Also, the entire area between the building and the property line contains a sidewalk which also serves as path of egress to the public way. Our lighting scheme provides a maximum of 0.61 footcandles (fc) of horizontal illuminance and 1.0 fc of vertical illumination at the property line, which is also the curb line of the sidewalk. However, at 10 feet beyond the property line, light levels are 0.01 fc, with 0 fc at 15 feet beyond the property line. We have achieved this by utilizing a low-wattage (13 watt), wide-distribution fluorescent source, mounted at a low height (3.5 feet) on the building wall that adjoins the sidewalk. This fixture emits all light at angles below 90 degrees. All other components of the project comply with this credit, and we would like to confirm that our approach regarding the egress path lighting meets LEED\'s intent to reduce light pollution while allowing the project to meet code and security requirements." "1. Uplighting under an opaque canopy If the uplight is COMPLETELY contained under an opaque canopy, it does not have to be considered in the uplight tabulation. To document this, the team must show that a) the canopy is indeed completely opaque and b) that all angles where a candela value is emitted from the luminaire are blocked by the canopy. Provide a specification for the canopy material and a line diagram showing the canopy/luminaire geometry. If the luminaire is adjustable, the team must show that it will be locked in position or that the canopy will block the light at all possible aiming angles. 2. Egress Lighting The team\'s proposal of using very a low wattage fluorescent lamp in a fully shielded luminaire will meet the intent of the credit while still providing the egress light necessary to meet code. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "2101" "2008-04-24" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "The project is a major renovation for a data center in an existing industrial park. The existing front parking area has an abundance of tree growth that effectively provides a cutoff of illumination generated from the pole mounted 250W HPS fixtures. The fixture is a cutoff type as required by the credit. Will it be acceptable to observe/record lighting levels at the property line in lieu of calculations? Any illumination calculations will not model tree growth and will show lighting to be non-conforming to the credit. But if we can submit recorded/observed lighting levels it is likely we will comply with the .2fc max." "The project team has asked if field measurements can be used instead of a computer simulation given that they cannot simulate the landscaping and the landscaping provides shielding.. No, field measurements are not acceptable because landscape and trees will grow or may be cut down, trimmed or changed in the future. Deciduous trees will lose their leaves for part of the year and provide a much lower shielding effect. Furthermore, the health of some species of trees may be negatively impacted by nighttime lighting. A lighting solution, based on a computer simulation without trees, that better controls the light to limit it at the tree line represents a strategy more in line with the intent of the light pollution credit. This may be accomplished with luminaire optics with a shorter ""forward throw"" or a lower wattage lamp. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2139" "2008-05-23" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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." "The project team is inquiring if it is acceptable to illuminate a controlled alleyway that abuts, but is not within, the project\'s property boundary and still comply with the intent of this credit. Previous CIR rulings, posted 1/24/2005, 9/2/2003, and 7/21/2003, illustrate similar project situations. Per the noted rulings, it may be possible for projects to comply provided the project team sufficiently documents that it is located within a high ambient brightness zone (LZ-4) and confirms that no illumination will enter any windows of any adjacent properties and that the light trespass is limited to 0.6fc on any adjacent site in the alleyway." "None" "None" "LEED Interpretation" "2153" "2008-06-19" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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 applicant is inquiring whether exceeding the illuminance values both for the property/curb line and 15ft beyond as required for LZ3- Medium Environmental Zone at egress areas while meeting the requirements at other areas is acceptable. In addition, the applicant indicates that the illuminance values maintained at the egress areas are required by code and are desirable for the safety and comfort of the occupants. The project cannot achieve SSc8 as currently described. In the CIR ruling 12/15/2006 light trespass only at entries are allowed to exceed the requirement at the property/curb line, but not 15ft beyond the property/curb line. For further clarification of the 12/15/2006 CIR, when using the curb line as the property line the proponent must document that the code requirement for egress lighting extends to the curb to exceed the trespass requirement at the curb line. In all areas the light trespass 15ft beyond the property/curb line must meet the 0.01fc requirement. Furthermore, the CIR process does not constitute credit acceptance, it is the project team\'s responsibility to fully document the credit requirements by citing referenced sources and providing relevant data when submitting the project for LEED review." "None" "None" "LEED Interpretation" "2342" "2008-10-16" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "Our project is a new 10,000 s.f. clinic building on a piece of property that is owned by the building owner/occupant. The owner/occupant originally purchased a 2.1 acre site that has been subdivided into two parcels, one a 1.1 acre site for this project and another 1 acre site that will be developed in the future. The overall site of 2.1 acres has been master planned to share site access, has shared parking easements and shared site lighting. The development has been approved as such by the city. Not knowing when the second parcel of land will be developed, we would like to design the site lighting to provide adequate lighting for safety and comfort at the site access (which the property line between the two parcels splits evenly) and provide for the most energy efficient lighting for both parcels. My concern for this credit is at the property line that separates these two shared parking areas and their site lighting. The shared site lighting design, which provides the most efficient lighting for both parcels, creates a light trespass problem at the property line that separates the two. By trying to meet the requirements for this credit and meet the light level requirements at the property lines, I don\'t provide adequate lighting for safety at our shared access to the site and by shifting light poles in board to the site I don\'t provide for the most energy efficient site lighting design and I don\'t provide adequate lighting in the parking lot area, next to the property line, for safety and comfort. All other property line required light levels will be met. Is it acceptable to design the site lighting to exceed the required lighting levels at this shared property line situation and be awarded the credit for Sustainable Sites Credit 8, Light Pollution Reduction?" "The applicant has requested clarification if light trespass thresholds are applicable along parcel property lines within a shared master site or campus. Per the LEED-NC Application Guide for Multiple Buildings and On-Campus Projects (AGMBC), this credit can be attempted at the campus level, negating the need to meet the light trespass thresholds along parcel property lines as long as the requirements are met for the campus as a whole. Please refer to the AGMBC (http://www.usgbc.org/ShowFile.aspx?DocumentID=1097) for additional details on attempting this credit at the campus level. \n\n***Update April 15, 2011: Please note that all 2009 projects in multiple building situations must follow the 2010 Application Guide for Multiple Buildings and On-Campus Building Projects, located here: https://www.usgbc.org/ShowFile.aspx?DocumentID=7987. 2009 project teams should check this document for up to date guidance on all multiple building issues. Applicable Internationally.\n\n***Update 1/1/13: LI 2342 has been superseded by LI 10236. 2342 is no longer valid." "10236" "None" "X" "LEED Interpretation" "3108" "2004-06-15" "New Construction, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "The S.T. Dana Building project is a renovation project located in the central quadrangle (the Diag) of the University of Michigan campus in Ann Arbor, Michigan. The site area defined for the project is the site surrounding the existing building which was directly affected by the construction project. In general terms, the site consists of a narrow band of space around the building and additional areas that were contained within construction staging areas for the project. This site definition is being applied consistently to all aspects of the LEED submission.\n\n The LEED application for the project includes documentation for the award of Sustainable Site Credit 8, Light Pollution Reduction. The project incorporates the replacement of exterior lighting over the two principal building entrances, areas approximately twenty feet square (20Æ x 20Æ). This is the full extent of exterior lighting undertaken as part of the Dana Building renovation project.\n\n The design of the replacement fixtures meets applicable IESNA requirements. The LEED application includes all required calculations and documentation showing compliance with IESNA for both interior fixtures casting light out windows and the exterior lighting at the building entrances replaced as part of the project.\n\n The basis of this inquiry addresses other, pre-existing, exterior lighting located within the defined LEED project site that is not being replaced as part of the renovation project. There are two types. First, attached to the building are bracket-mounted lights above each of two secondary doorways. These lights have not been replaced as part of the renovation project. Second, is a series of low pole fixtures lighting the pedestrian pathways around the building. The pole fixtures have not been replaced as part of the renovation project.\n\n The proposed light fixture replacement does achieve light pollution reduction within the limitations of the project scope. Following the no action / no credit philosophy, it is our position that no action regarding exterior lighting that is beyond the scope of the LEED renovation project means no penalty either. Can the project be awarded Sustainable Site Credit 8 for replacement of the two main entrance fixtures alone? " "The intent of the credit addresses a project's ""building and site."" The bracket-mounted lights above the secondary doorways are part of the building, and thus certainly need to meet the LEED requirements. Site/pathway lighting is not as straightforward a scenario. \n\n Your building project is within a university campus context and thus site lighting choices are possibly controlled by a central design plan for reasons such as security and consistent aesthetics. Granted this situation presents challenges in applying LEED-NC, but SSc8 is about delivering a specific type of lighting performance for the entire project, not for selected pieces of it. As stated in your narrative, the ôsite definition is being applied consistently to all aspects of the LEED submissionö û as USGBC requires.\n\n Given the projectÆs context, however, USGBC is willing to offer an alternative compliance path on university campuses for existing site lighting that falls within the site boundaries per the LEED application (in this case, the low pole fixtures that are not slated for replacement) IF it is shown that the Campus Exterior Lighting Master Plan (if it exists) has been officially upgraded to a SSc8-compliant level (assumably after the low pole fixtures were installed) by the time of LEED application submittal û whether or not it has been inspired by striving for this LEED point. In addition, since the ""property boundary"" in this case is created for administrative purposes only ùdefined for the project's scope (as well as LEED application) ù the SSc8 requirements relating to the property line need only be followed for the REAL campus property boundary, rather than the PROJECT boundary. This compromise ensures that all future site lighting installations on the campus will serve the intent of the credit and thus achieve performance beyond what would be accomplished through solely replacing the project siteÆs pole fixtures.\n\n If no Campus Exterior Lighting Master Plan exists, or it has not been updated to comply with SSc8, then the site lighting in question must be changed to comply with SSc8 in order to achieve the credit. Look into the possibility of retrofitting (via lumen and shielding changes), or replacing the fixtures outright. \n Applicable Internationally. " "10236" "None" "X" "LEED Interpretation" "3113" "2005-01-24" "New Construction, Schools - New Construction, Core and Shell, Existing Buildings" "SSc8 - Light pollution reduction" "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.\n\nOur 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.\n\nI 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).\n\nI would appreciate your view on this particular situation." "There are multiple components of this CIR that are addressed in the five points below.\n\n1. Pedestrian Indirect Lighting: Pages 71 & 72 of the LEED-NC v2.1 Reference Guide discusses design approach strategies to comply with the intent of Sustainable Sites Credit 8. The Guide states ""In areas of high ambient brightness, some low level (subtle) lighting of features, facades or landscape areas may be appropriate in pedestrian environments or for identification and way finding"" Uplighting a translucent canopy that is continuous around two facades of the building is not consistent with the intent of this credit.\n\nTo be more consistent with the credit intent, the following steps may help achieve SSc8: (a) Limit uplighting the translucent canopy to key focal points such as main entrances or use opaque material for the continuous canopies. Also, for uplighted areas, provide information about the translucent canopy, showing that the transmittance of the canopy has been minimized. (b) Show that the light distribution is limited to the canopy and does not spill beyond. To help clarify the design, provide a section showing the relationship of the luminaire to the canopy, showing that the photometric distribution from the luminaire is entirely captured by the canopy. (c) Specify a lamp package that has 3500 initial lumens or less. The standard lamp for the Bega 7475MH is a 70 watt metal halide with 6400 initial lumens, which will not meet the credit requirement. (d) Specify a luminaire that has a fixed, non-adjustable mounting. The Bega 7475MH is an adjustable luminaire that would allow changing of the intended aiming after the installation is complete, and refer to item (b).\n\n2. Alley Lighting: It is not clear that the Ruud E8-F luminaire meets IESNA Full Cut-off classification, therefore the lamp package must be 3500 initial lumens or less to comply with this credit, or supply documentation showing that the luminaire meets the full cutoff requirements.\n\n3. Light Trespass to Alley and Sidewalk: 2 - 10 footcandles far exceeds the limitation of 0.6 as stated in Table 1 on page 70 of the LEED-NC v2.1 Reference Guide. Refer to SSc8 LEED Interpretation Inquiry #5409 (request date 8/16/2003, ruling date 9/2/2003). Include detailed calculations and drawings similar to those on page 75 of the Reference Guide, showing (a) that the light trespass limitation of 0.6 is met at the curb line of the sidewalk of the 2 street sides and (b) that no direct beam illumination will enter any windows of any adjacent properties and that the light trespass is limited to 0.6fc at the window locations in the alley.\n\n4. Parking Garage Lighting: For all levels of the parking garage, show that the peak candela of the luminaires falls within the parking garage. If the top level of the parking garage is open to the sky, provide luminaire cutsheets showing that they meet IESNA full cut-off classification, and meet all other exterior requirements.\n\n5. Lobby Lighting: From the description provided, the lighting in the lobby satisfies the requirements of SSc8. Provide a diagram and photometric distributions of luminaires showing that the peak candela falls within the building. Note: all other interior lighting must also meet the requirement that the peak candela falls within the building." "None" "None" "LEED Interpretation" "3128" "2005-07-29" "New Construction, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "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?" "Flag lighting has been a controversial topic within LEED and CIRs. Based on a further interpretation of the CIR ruling dated 3/14/2003, lighting the American/National flag has been deemed acceptable under LEED if a maximum of 3 luminaires (utilizing less than 3500 initial lamp lumens each) is used for only one pole location on the property, and only in areas of high ambient brightness. The luminaires must be controlled such that they will be automatically shut off during after-hours and during post curfew periods.\n\nOtherwise, in accordance with the CIR ruling dated 2/8/2002, ""The first article of the Federal Flag Code suggests that it is the universal custom to display the flag only from sunrise to sunset on buildings and on stationary flagstaffs in the open. As this fundamental flag custom and expression of patriotism works in concert with a sustainable approach to site lighting, no exception will be granted...""." "10008, 100000740, 100000741" "None" "LEED Interpretation" "5016" "2006-02-07" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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." "Determination of the appropriate Environmental Zone is critical in achieving SSc8. This designation is especially important for projects close to any residential area where stray light or brightness could affect sleeping areas. E4 is only appropriate for Major City Centers and Entertainment Districts, E3 is appropriate for Commercial/Industrial or High Density Residential areas, E2 is appropriate for Residential Areas. It appears from the description in the CIR that this project is not in an E4 zone. More details are needed about adjacent areas; is the general area residential (E2), commercial /industrial (E3) or a core downtown area (E4). The project team should provide substantiation to demonstrate which level the project is (E2, E3 or E4), as they have not done so in the CIR. Your approach to extracting appropriate criteria from the IESNA document for the pedestrian walkways and meeting all other SSc8 criteria is acceptable. However, in keeping with 6/15/2004 CIR Ruling: the SSc8 requirements relating to the property line need only be followed for the REAL campus property boundary, rather than the PROJECT boundary. If it is shown that the Campus Exterior Lighting Master Plan (if it exists) has been officially upgraded to a SSc8-compliant level by the time of LEED application submittal. If no Campus Exterior Lighting Master Plan exists, or it has not been updated to comply with SSc8, then the site lighting in question must be changed to comply with SSc8 in order to achieve the credit. Applicable Internationally. " "10236" "None" "X" "LEED Interpretation" "5054" "2007-06-15" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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 project, as described, does not meet the full requirements of the credit. The applicant has quoted the requirements from the initial credit description, but more detailed requirements are laid out in the Approach and Implementation section of the LEED-NC v2.2 Reference Guide SSc8 description, including ""preventing light spill through transparent and translucent surfaces to exterior areas"" and to ""confirm that the maximum candela angle does not intersect transparent or translucent building surfaces that face exterior areas."" If it is not possible to alter the building design to meet the requirements described above, it is still possible to achieve the credit using the alternate compliance path presented in ""Option 2"" of the Interior Building Lighting section in the Reference Guide." "None" "None" "LEED Interpretation" "5105" "2008-01-28" "New Construction, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "The Argiro Student Center project has chosen to address one of the criteria in the Light Pollution Reduction credit in a way that differs from the strategies in the LEED-NC Manual. We have chosen to officially establish that the full time janitorial staff, who go into the building for routine cleaning purposes at night, ensure, as part of their necessary responsibilities, that all lights are turned off after hours. This strategy should effectively eliminate undue light trespass from the building in the evening hours and, thereby, this strategy should adequately fulfill the intention of the ""minimize light trespass from the building"" aspect of the Light Pollution Reduction credit. This compliance route may take the place of the suggestion that: ""all non-emergency interior lighting shall be automatically controlled to turn off during non-business hours."" The project has chosen alternative compliance for the first part of this credit. And the project intends to fulfill the requirements for exterior lighting as listed in the manual. If the USGBC accepts our alternative compliance route then we may plan to receive a credit for our work in this category." "The team proposed an alternate compliance path where the custodial staff would turn off the interior lights at night to minimize light spill and trespass. This does not qualify as an approved compliance path for the following reasons: Applicable Internationally." "None" "None" "X" "LEED Interpretation" "5109" "2008-01-28" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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." "The Approach and Implementation section of the SSc8 Reference Guide credit description allows for the following lighting control strategies to meet the intent of the second compliance path: ""Controls may be automatic sweep timers, occupancy sensors, or programmed master lighting control panels. Manual override capabilities that enable lights to be turned on for after-hours use must be included in the design."" As described, the lighting control for student accessible spaces sounds appropriate, as it is based on occupancy sensors with over-ride switches. Obviously in a dormitory setting there is a certain baseline-level amount of lighting that is required at all times for security purposes. If a light fixture is to remain on through the entire night, it should meet the requirements of the first compliance path, namely the angle of maximum candela should not pass through transparent or translucent building surfaces. Defensible exceptions can be made at entrances and exits to the building where required for safety. Please note that you would also have to address credit compliance for those spaces that have not been mentioned in this CIR (such as areas off-limits to students, which do not require 24 hour lighting). Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5149" "2008-09-25" "New Construction, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "Our project is a multifamily residential building and we would like an interpretation on the requirements of this credit: For Interior Lighting: Based on the type of spaces and their occupancy hours, we intend to use both option 1 and option 2 to meet the interior lighting requirements: a) Option 1 for all corridors since they are required to be lit during the night for the safety of the residents. Please confirm. b) Option 2 for all the other common areas- clubhouse, maintenance rooms etc, since these will function during business hours only. Please confirm. c) Per CIR ruling 1/28/2008, 'Defensible exceptions can be made at entrances and exits to the building where required for safety'. Therefore the stairwells (which are means of egress and have to be lit at a certain light level per code) will be excluded from meeting the requirements of either option 1 or 2. Please confirm. d) We feel that the residential unit lighting should be exempt from meeting the interior lighting requirements because of the following reasons: i) For the residential units regular business hours do not apply-hence option 2 will not be applicable. ii) In order to meet option 1 photometric data of the luminaires is required to ensure that the angle of the maximum candela of each installed luminaire intersects opaque surfaces and not exit out through the windows. Residential grade fixtures do not have photometric data available -so the design team is unable to determine the angle of maximum candela for each interior luminaire to meet requirements of option 1. iii) It can be assumed that most lights in the residential units will be turned off during the late night period so there will be minimal light escaping through the windows. iv) Further, the light will be prevented from escaping through the windows because of the interior blinds that will be provided at each window. v) Finally, it appears from CIR ruling 1/28/08 that the dormitory areas are exempt from meeting the interior lighting requirements. Based on the above, we would like to know if the permanently installed interior lighting in the residential units can be exempt from meeting the interior lighting requirements of this credit? e) The garage is surrounded by units on four sides,however there is a 15 foot gap between the garage and the units. The garage is open on two sides to be classified as an open garage. Since the garage is surrounded on all sides, the living units prevent light from spilling out beyond the building perimeter. Does this meet the intent of option 1? For exterior lighting We will be providing all exterior lighting fixtures to meet the requirements of this credit. Clarification is needed for the wall mounted light fixtures in the recessed covered resident balconies -should they be assumed as building façade fixtures or would they be regarded as canopy/overhang fixtures?" "The applicant appears to be requesting clarification for the following questions: [1] can Option 1 and Option 2 of the interior lighting requirements be implemented on a space-by-space basis, [2] are stairwells exempt from the interior lighting requirements, [3] are residential units exempt from the interior lighting requirements, [4] is an open parking garage which is surrounded on all sides by additional buildings associated with the project exempt from the light trespass requirements, [5] are wall fixtures in resident balconies façade or canopy lighting. The responses to each of the questions are as follows: [1] The proposed approach is acceptable. Spaces are required to either satisfy interior lighting requirements using Option 1 (i.e., minimize light penetration through opaque surfaces) or Option 2 (i.e., install automatic lighting control). [2] The interior lighting requirements may be exempted for fixtures at building entrances and exits per the CIR dated 1/28/08 provided that the fixtures are required for safety. The project team shall submit a copy of the applicable standard with the relevant emergency lighting requirements highlighted. However, for stairwell lighting to be exempt the output shall not exceed 2 times the code required light level. [3] ***SECTION 3 HAS BEEN OVERRULED BY INTERPRETATION #10147 AS OF 4/1/12*** Residential spaces may not be exempted from the interior lighting requirements. The CIR dated 1/28/08 that is referenced in the request does not specifically address the residential spaces of the dormitory. However, as an alternative for residential spaces, demonstrate that less than 10% of the total lumens emitted by each luminaire are not directly emitted out of the building through any fenestration. [4] An open parking garage that is surrounded by additional buildings associated with the project is not exempt from the ambient light trespass requirements of the credit. Light from the garage fixtures may pass between or over the buildings surrounding the garage depending on the heights and orientations of the parking garage and buildings. Please note that the project documentation must also demonstrate that the interior light trespass requirements are satisfied for covered areas of the parking ramp. Please refer to the CIR dated 12/18/2007 for additional information. [5] If the intent of the wall mounted light fixtures in the recessed covered resident balconies is to light the floor of the balcony then the fixtures would be part of the “canopy/overhang lighting” budget. If the intent is to highlight the walls then they would be part of the “façade lighting” budget." "10147" "None" "LEED Interpretation" "5188" "2009-02-11" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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." "The project team is requesting if the above three unique circumstances will exempt them from the light trespass requirements along their entire south property line. As described, the approach is not considered to be acceptable. While in certain limited circumstances (such as lighting shared infrastructure, or where the site boundary abuts a public right of way) it is permissible to extend the boundary applicable to this credit (to the extent of the shared infrastructure or to the curb), it is not permissible to exempt a project boundary from the requirements." "10236" "None" "LEED Interpretation" "5192" "2009-05-06" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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?" "The applicant is requesting confirmation if it is acceptable to exceed the lighting power density requirements with motion responsive after?hours security lighting that is only enabled when the other site lighting is off. Based on the description provided, this strategy is only acceptable provided that when the security lighting is ON, the combined security and general lighting that remains ON, does not exceed the lighting power density thresholds and the security lighting is capable of being controlled to prevent simultaneous operation with the offsetting exterior luminaires. The second question asks if the lights can be excluded from the other requirements of SSc8 and the answer is no. These luminaires must meet the light trespass requirements relative to their declared environmental zone at the applicable site boundary, as well as the sky glow requirements of the credit. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5245" "2003-03-14" "New Construction, Schools - New Construction, Core and Shell, Existing Buildings" "SSc8 - Light pollution reduction" "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.\n\nBeginning 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.\n\nThe 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.\n\nPlease 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.""" "Under LEED v2.0, uplights are precluded in achieving this credit, as they represent direct beam illumination to the night sky. Under LEED v2.1, clarifications have been made that allow some limited uplighting, primarily for the purposes of lighting the American flag at night.\n\nIn areas of high ambient brightness only, limited uplighting will be allowed if the following conditions are met: (1) All credit requirements are met, including full cut off luminaires for lamps over 3500 initial lumens and shielding for those over 1000 initial lumens. (2) Lighting controls are used to turn off lighting after hours and/or during post curfew periods. A plan should be developed to insure the use of the controls (automated controls, etc.). Note that some landscape features such as trees and plants (depending somewhat on the type of planting) require a rest from light. (3) Lighting controls are commissioned.\n\nIn addition to the above conditions (and associated documentation), certain additional information must be provided to demonstrate compliance with the credit intent: (1) The results of a light study that verifies the illumination intensity emitted directly above the feature being lit (in this case, the fountains and the trees). (1a) If trees are being uplit, this study must verify the maximum light levels that will be produced when the trees have dropped all of their leaves. (2) A narrative describing how light levels and glare will be controlled around the trees in each of the seasons and listing the hours of intended uplighting operation for both the water feature and the plaza tree lighting. (3) A statement from your landscape architect indicating that the planned tree lighting will not have adverse effects on the trees\' dormancy cycles. (4) Confirmation that the fixtures and lamps installed are the same as those modeled.\n\nNote: the v2.1 Reference Guide language will provide further clarifications; please refer to that document before finalizing your design." "None" "None" "LEED Interpretation" "5408" "2003-07-21" "New Construction, Schools - New Construction, Core and Shell" "SSc8 - Light pollution reduction" "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.\nAs 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.\nThe 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 .\nThe 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.\n\nPlease confirm that this schedule and approach are consistent with the USGBC\'s previous credit ruling on this subject." "Yes, your approach is consistent with previous guidance. Per the Credit Ruling dated 3/14/2003, limited uplighting is allowed under LEED Version 2.1 in areas of high ambient brightness. Table 1 on page 70 of the LEED v2.1 Reference Guide, which is adapted from the referenced standard (IESNA RP-33-99), describes light trespass limitations for four distinct environmental zones. The project team states that the project is in an area that has a ""fair amount of ambient brightness"". The project team would first have to document that the building is indeed in an environmental zone of high ambient brightness.\n\nOnce that requirement is met, the project team would earn the credit if ALL of the requirements outlined and the cited Credit Ruling are met AND lighting is limited to 0.2 watts/SF of object footprint (canopy area) - as currently proposed for the lighting requirements of ASHRAE 90.1-2004. Summarize the details in a narrative for this credit in your LEED application and confirm that the installed fixtures and lamps are the same as those specified. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5409" "2003-09-02" "New Construction, Core and Shell, Schools - New Construction" "SSc8 - Light pollution reduction" "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.\nAll 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.\nThe 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." "As was stated in the 7/21/2003 Project ManagerÆs Rulingà ôTable 1 on page 70 of the LEED v2.1 Reference Guide, which is adapted from the referenced standard (IESNA RP-33-99), describes light trespass limitations for four distinct environmental zones.ö If in fact your project falls within the Environmental Zone E4 Areas of high ambient brightness, then the limitation for light trespass onto adjacent properties is 6 lux (0.6 fc). As illustrated in the example contained on page 75 of the LEED v2.1 Reference Guide, the ôline of site illuminanceö must be calculated for the adjacent luminaire. Since, from your description, it appears that any illuminance will trespass onto another property, additional information must be provided. Include detailed calculations and drawings similar to those on page 75 of the LEED v2.1 Reference Guide, showing that no direct beam illumination will enter any windows of any adjacent properties and that the light trespass is limited to 0.6fc at the window locations. If it is determined that the light trespass is greater than allowable, then the credit is not attainable." "None" "None" "LEED Interpretation" "5722" "2007-06-15" "New Construction" "SSc8 - Light pollution reduction" "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 project, as described, does not meet the full requirements of the credit. The applicant has quoted the requirements from the initial credit description, but more detailed requirements are laid out in the Approach and Implementation section of the LEED-NC v2.2 Reference Guide SSc8 description, including ""preventing light spill through transparent and translucent surfaces to exterior areas"" and to ""confirm that the maximum candela angle does not intersect transparent or translucent building surfaces that face exterior areas."" If it is not possible to alter the building design to meet the requirements described above, it is still possible to achieve the credit using the alternate compliance path presented in ""Option 2"" of the Interior Building Lighting section in the Reference Guide. Applicable internationally. " "None" "None" "X"