Identifying design shortcomings and heat-island effects in schools located in warm climates: An outdoor environmental assessment procedure based on remote sensing tools

Abstract

The current effects of global warming and a growing obsolescence in the built environment are rendering outdoor areas of existing schools thermally vulnerable and uncomfortable, thereby causing unsuitably hot temperatures during the academic year. This paper aims to diagnose and reveal the main weaknesses and design shortcomings in outdoor areas of schools. To this end, this research contributes with a normalised characterisation procedure that provides quantified parameters that not only focuses on design patterns and wooded and shaded spaces (Normalised Difference Vegetation Index), but also on ground materials (Solar Reflectance Index) in order to reduce the impact of solar radiation and adjust future renovation strategies for southern European schools. With the novelty of using remote sensing tools and in situ measurements , an outdoor environmental assessment is made of a representative sample of 100 schools in Andalusia, a Mediterranean region in southern Spain. The results demonstrate that shade percentages are greatly limited, whereby 90% of schools contain between 0 and 10% of wooded area, mostly with a vegetation index in the range of 0–0.3, along with 70% of centres with more than 80% of their ground area covered with hard paving, thereby involving a higher absorption of solar energy. Conclusions not only identify weaknesses and design shortcomings and highlight key implications based on the promotion of heat mitigation strategies through bioclimatic renovation actions, but they also provide ranges of recommended values for the established indices, towards achieving more shaded and comfortable areas in schools. • Need to reconsider new design patterns for school playgrounds due to global warming. • Remote sensing is used as a key tool to diagnose the heat island effects in schools. • Shaded areas are low with 0–10% wooded and 0–0.3 vegetation index in warm climates. • High absorption of solar energy due to hard paving and dark colours in 80% centres. • Final policy implications towards implementing bioclimatic strategies in schools.