Outdoor thermal benchmarks and thermal safety for children: A study in China's cold region

Abstract

Outdoor spaces in parks designed for children's recreation are highly valued facilities that support physical health and well-being for parents and youth. Key to their use is the perception of thermal comfort. To this end, a questionnaire study of thermal perception in representative open spaces in a children's park in Xi'an, China was conducted. Child thermal benchmarks in Xi'an and thermal safety were evaluated using the universal thermal climate index (UTCI) with material surface temperatures (Ts) in open spaces. Bioclimatic design strategies for open spaces were proposed based on children's thermal benchmarks and Ts. We draw four conclusions: 1) Globe temperature (Tg) and air temperature (Ta) were the primary meteorological factors influencing children's thermal sensation. 2) Neutral UTCI (NUTCI) for male and female children were 13.7 °C and 15.3 °C, NUTCI ranges were 6.1–21.3 °C (male) and 8.1–22.5 °C (female), the preferred UTCIs were 20.0 °C (male) and 19.7 °C (female), and acceptable UTCI ranged from 6.5 to 26.4 °C (male) and 5.7 to 27.3 °C (female). 3) Ts of asphalt, water permeable bricks, wood (ground) and wood (chair) were high in the sun, threatening children's thermal safety; Ts of all tested materials was low in the shade with no heat risk in normal use. 4) Bioclimatic design strategies were proposed based on children's thermal benchmarks and Ts of materials including vegetation, materials and built facilities. The results provide guidelines for urban planners and landscape architects to create age-appropriate open spaces that mitigate urban heating, reduce summer sun exposure and improve park usability in China's cold region.