Heat stress in hospital ward spaces: An investigation on a naturally ventilated hospital building in UK

In the context of climate change, there is increasing concern about the likelihood of overheating in hospitals in UK, especially in buildings which are not mechanically cooled. A number of studies have examined this issue in different hospitals in UK. On most occasions these studies have focused on overheating and evaluated the performance of the spaces using adaptive thermal comfort criteria. Adaptive criteria is not a good indicator of actual heat stress. Further, the adaptive criteria cannot be applied to spaces that have no operable windows. However, in hospital, substantial number of spaces are without windows, especially nurse stations. This paper will assess the heat stress in ward spaces using Wet Bulb Globe Temperature (WBGT) heat index in order to explain the occupant’s vulnerability while looking at the potential of combining this index with adaptive thermal comfort criteria (BSEN15251). The paper will focus on naturally ventilated Runcie ward building at St Albans city hospital and assess its thermal performance for summer 2011. During summer 2011, the maximum WBGT varies between 21.5?C and 23.8?C while the minimum was between 13.6?C and 14.3?C. The paper proposes WBGT of 23?C as a heat stress threshold for sick and vulnerable.