The increasing presence of sky glow—a reduction of night-sky visibility from greater levels of scattered light—has been a topic of growing concern among the lighting community for some time. But, short of following general design guidance, there are few simple means of estimating a lighting product’s specific influence on the phenomenon, or of identifying the most effective approaches for addressing it. The Building Technologies Office (BTO) is interested in this research topic as it impacts the installation of energy efficient LED street lighting.
Following the completion of a recent LED Street Lighting and Sky Glow Investigation, researchers at Pacific Northwest National Laboratory developed a simplified method for comparing contributions to sky glow among lighting products by using various combinations of output characteristics (e.g., spectral content, light output level, percent uplight). The methodology arose out of the large dataset generated from more than 215,000 model runs during the process of the investigation.
This methodology has since been incorporated into a spreadsheet, now referred to as the Sky Glow Comparison Tool, which enables a relatively simple, first-principles comparison of the contributions to sky glow from various combinations of the noted lighting characteristics. The comparison tool was designed to be user-friendly with inputs and outputs readily familiar to the lighting community, and it addresses an existing gap in their design toolkit.
On November 8, Bruce Kinzey of Pacific Northwest National Laboratory described and demonstrated use of the comparison tool in an hour-long webinar.