Our project is located at the intersection of two major arterial streets in an urban renewal area in Salt Lake City. IESNA Zone E-4, or brighter. The project is a four story adaptive reuse / restoration of a 1922 industrial building. The new owner is a general contractor who has embraced urban renewal by investing in an area that would otherwise continue to decay. The immediate neighbors include typical older industrial buildings, some rehabilitated, others not. The area is the host to 3 transient shelters and a rail yard. Immediately adjacent is a city park that attracts transients and other less than desirable traffic. Considering these factors, we have selected site lighting which maintains safety for pedestrians and security of the building and the vehicles parked in the owner\'s parking lot. City street lights illuminate each of the arterial streets bordering the project. These lights are city selected and installed and are acorn type arrays with 3 heads totaling 900 watts (107,000 lumens) of HPS light each. There is no optical direction or cut-off control. In order to respond to site geometry, security concerns, and the transition to brightly lit city streets, 20\' pole mounted lights were located at or near the property perimeter. These lights are 200 watt pulse start metal halide lamps in IESNA full cutoff luminaires with house side shields. Nevertheless there are a limited number of areas where some light trespasses onto the street and an adjacent parking lot. The light trespass level ranges from 0.1 to 0.4 footcandles and is not detectable when standing on site because of the high ambient city lighting. The entire parking are is lighted to comply with the relevant IESNA recommended practice IESNA RP-20-9 8 (Enhanced Security), RP-33, and the 9th Edition of the IESNA Lighting Handbook. We believe that the project responds to both the neighborhood and the credit requirement intention. We would like an interpretation of the SS Cr. 8 requirements with regard to our specific site lighting environment and light trespass situation.
The information provided in the inquiry raises three issues that the project team should address relative to the credit\'s requirements: 1. If the city street lights are being installed as part of the project scope and they are located within the project\'s site boundary (which must be defined consistently for all LEED credits), these fixtures must comply with credit requirements. Accordingly, they must meet the Full Cutoff IESNA Classification (since more than 3500 initial lamp lumens), and the illuminance they generate must be included in the project\'s photometric and light trespass calculations. If these fixtures are not part of the project scope or LEED site, they can be excluded. 2. It appears from the description in the inquiry that the project\'s other exterior lighting fixtures are compliant, since they are full cutoff, but any light trespass that they generate cannot exceed 0.6 fc , as indicated in Table 1 on page 70 of the LEED V2.1 Reference Guide (for this E4 High Ambient Brightness zone). In order to calculate light trespass values, horizontal fc levels indicated on photometric site plans must be converted to "line of sight illuminance" where these calculated light levels do not reach zero at the property line. Refer to pages 74-76 of the LEED 2.1 Reference Guide (May 2003) for the calculation methodology utilized to calculate line of sight illuminance. 3. If the parking lot is part of the project scope and located within the defined LEED site boundary, its lighting must comply with IESNA RP-20-98 recommendations, as stated in the inquiry. Based upon the description provided, it would be acceptable to utilize the "Enhanced Security" illuminance values from the reference standard for this parking lot. (See Table 1 on page 3 of IESNA RP-20-98) If the above three issues can be addressed satisfactorily, and if the photometric calculations and luminaire data described in the inquiry demonstrate compliance with credit requirements, achievement is likely. Applicable internationally.