Alliance for Lighting Information

PIER Unit Power Density

by Jefferey F. Knox

In reviewing the data published with this report for glare readings produced by 1000-watt lamps or higher, the following general information was discovered. It would appear that if a single luminaire was used to light more than one functional use area on the site, the entire wattage of the luminaire was assigned to each of the functional use areas. Refer to the data for sites 664, 1769, and 623. This would seriously increase the unit power density associated with the individual functional use areas and for the site as a whole. This problem was found in the data for three out of nine sites for which the data was reviewed. When this data is scaled up the significance of the error is magnified.

Table 51 indicates that this may be the case. When the percentages for 'all FUAs' are summed the total is 158.8% - this indicates that approximately half of the luminaires light at least two different FUAs. This demonstrates a flaw in the methodology, by not analyzing the 'functional use areas' contextually as part of a whole site.

• Public Interest Energy Research (PIER) program's Outdoor Lighting Baseline Assessment Final Report - Follow the link to the registration page to download the Element 7 Report.
• ALI PIER Review Summary
• ALI: PIER Glare Ratio
• ALI: PIER Lamp Replacement Scenarios
• ALI: PIER Lighting Satisfaction Survey
• ALI: PIER Sample Design Methodology
• ALI: PIER Scientific Methods
• ALI: PIER Statistical Data
• ALI Home Page

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