Proceedings of 8 th Windsor Conference: Counting the Cost of Comfort in a changing world, Cumberland Lodge, Windsor, UK, 10-13 April 2014. London: Network for Comfort and Energy Use in Buildings, http://nceub.org.uk Thermal acceptability for urban parks in tropics: Evaluating the effects of environmental attributes on user perceived controls Indrika Rajapaksha and Chathuri Rathnayaka Department of Architecture, University of Moratuwa, Sri Lanka, indrika@uom.lk Abstract Though wider diversities of environmental attributes are intrinsic in water fringed urban parks, these parks are less represented in the previous studies. Thus the study aims to explore the impact of environmental attributes of settings on user perceived controls for enhancing daytime thermal acceptability of water fringed urban parks in Colombo, Sri Lanka. The study investigated seven diversified settings which demonstrate varying shading levels and environmental attributes with visual integration of water surfaces. Although predicted thermal perception indices signify uncomfortable microclimates majority of the visitors are accepting high PET range of 28-40°C. Enhanced thermal acceptability of these parks is related to visitor's perceived control on choice of place. The tolerance of extremely hot microclimates is encouraged through more natural environmental attributes of the settings which contribute to visitor's expectation of view for high degree of perceived control. Thus microclimate planning which link visitor's expectation through natural environmental attributes of urban parks is prime importance for usability and vivacity of outdoor settings in tropical climates. Keywords: Tropics, thermal acceptability, urban parks, perceived control, environmental attributes 1 Introduction Urban outdoor areas are vital spatial elements of an urban fabric, which contributes to enhance quality of life within cities. With, the focus of urban population growth for next 30 years in developing countries of Asia, tropical urbanization is an appealing global phenomenon. Haphazard densification, declining urban green plot ratio and emergent urban heat islands in tropical cities contribute to varying warmer outdoor microclimates. Over the recent years urban outdoor environments such as, parks and squares in various countries and climate zones have received increasing research attention. Many studies have investigated the outdoor thermal environments, thermal adaptation and utilization of urban outdoor spaces in moderate climates in European cities including; Cambridge, the UK (Nikolopoulou, M. et al.,2001); Göteborg, Sweden (Thorsson et al.,2004); Kassel, Germany(Katzschner,2006), Athens, Greece (Nikolopoulou et al.(2007); Szeged, Hungary (Kántor, N. et al.,2011); Hague, Eindhoven and Groningen, the Netherlands (Lenzholzer, S. et al.,2010). Similar attention was evident for onsite research in outdoor spaces with hot and humid subtropical and tropical climatic conditions in quite a few Asian cities such as, Taichung, Taiwan (Lin, T.,2009; Lin, C. et al.2013), Shanghai, China (Xu,J. (2010), Singapore (Yang.W.,2013), Dhaka, Bangladesh (Ahmed,K.2003), Salngor, Malaysia (Nasir et al.2013).