Optimizing the Seasonal Shade and Ultraviolet Protection of a Suburban Playground by Utilization of the Playground Shade Index.

The Playground Shade Index (PSI) is introduced as a design metric for assessing the shade and solar ultraviolet (UV) protection provided by eight different cloth weave shade structures currently utilized in public playgrounds across a regional city located in southern Queensland, Australia. The PSI, expressing the ratio of available ambient solar UV exposure relative to the UV exposure received by a shaded 184 m playground surface over a whole day in midsummer and midwinter, is used to determine the best design and aspect of all eight existing structures. Unlike subjective shade audits that may only consider the type of shade structure, the number and characteristics of surrounding trees, and surface materials available at a given site, the PSI considers, in addition to previous factors, the available sky fraction and the direct solar UV contribution underneath the shade structure over a full day. By considering the in situ UV protection characteristics of the shade structure, the PSI has demonstrated its value as a robust design metric. Of the eight shade structure styles examined, this research presents the most likely structure best suited for UV protection over the two solar UV extremes in summer and winter, including optimal structure aspect.