Sky-glow conscious lighting design†

Abstract

As society becomes more environmentally conscious the problems of obtrusive light, and particularly 'sky glow', have led many road lighting engineers to demand full cut-off luminaires emitting no light whatsoever above the horizontal. This paper looks at the range of existing fixed-angle exterior luminaires and suggests a classification for them which accommodates the wide variety of designs and requirements for the aesthetic appearance and need for light on some high vertical surfaces. The brightness of floodlit buildings is also discussed as a growing number of people feel that luminance, not illuminance should be the design criterion for helping to reduce the many over-bright installations that are also causing unnecessary light pollution.