Part of the proposed complex lighting includes a lighted parking lot. Shive-Hattery Architecture+Engineeering was retained to study the proposed parking lot lighting designs and provide the following:
• An opinion on the design for dealing with light trespass issues.
• A determination of whether the lighting design meets the City of Davenport Code for exterior illumination.
• Other recommendations on how the impact of exterior lighting can be minimized in the surrounding neighborhoods.
Davenport City Code (Ch.17.56.040 O Exterior Lighting Standards) limits the height of lightning for exterior use to 30 feet and maximum illumination of 2.0 foot candles (fc). The standard further states the luminaire should be shielded to prevent light and glare spillover to adjacent residential property.
To provide minimum light spillover and decrease glare the use of full cut off and house side shields was recommended for fixtures located closest to residential neighborhoods. A sample lighting design was completed using LSI XAMU-3-LED-HO-CW-UE-HSS and XAMU-FT-LED-128-HO-CW-UE-HSS, which is the typical fixture the University plans on using. Both single and multi-head poles were utilized.
Shive-Hattery recommended that a design with 25-foot pole mounting height be used to minimize light spill and glare. It further recommended that house side shields be provided on perimeter fixtures to minimize any spill behind the fixture. This light complies with the City of Davenport's zoning code calling for minimized glare and spillover. This design provides the least off site impact from the parking lighting.
Lighting calculations were done using Visual Professional version 2.06.0232 and LSI provided IES files, and assumed a fixture mounting height of 25 feet. The study showed light levels 40 feet off the back of the proposed parking to be calculated at 0.0 foot candle on the residential side of the parking lot. This would be well within the requirement of the City of Davenport code for exterior illumination.