Thermal Comfort and Heat Stress of the Elderly in Hot-Humid Summers in Thailand

This thesis investigates how the elderly in hot-humid Thailand respond to heatexposure in terms of thermal comfort and heat stress levels and what adaptive action theytake to be comfortable. Data was collected from 135 elderly people who live in Chiangmai,Thailand. They were interviewed in a semi-outdoor space about three thermal perceptions:sensation, preference and acceptability. The survey covered subjective responses totemperature, wind, solar radiation, relative humidity and sweating. Three surveys wereconducted: the exploratory, the pilot and the main surveys during 2014 – 2015.The results show that 36°C is a ‘comfortably warm’ temperature as measured by thethermal comfort vote (TCV), while 38°C is an ‘unacceptable’ temperature under the thermalacceptability vote (TAV). According to the adaptive thermal comfort model, 36°C is thecomfort temperature (Tcomf) for the elderly in summer. Multivariate analysis shows that theTCV is affected more by subjective thermal responses than directly by the physicalenvironment. The solar radiation sensation vote (SSV) shows the highest impact on TCV.Regarding the factors impacting on thermal comfort, the elderly felt that sweatingand temperature concerned them the most. Drinking water and showering are the mostfrequent adaptive behaviours employed to relieve the heat. Five heat stress indices wereevaluated in this thesis: the Universal Thermal Climate Index (UTCI), Heat Stress Index (HSI),Tropical Summer Index (TSI), Wet-bulb Globe Temperature Index (WBGT) and DiscomfortIndex (DI). The UTCI, WBGT and DI group tropical conditions in the zone of greatest thermalstress, while the HSI and TSI impact categories are clustered in the lower heat stress zoneand are more comparable with the thermal sensation vote (TSV) and TCV definitions. Theresearch concluded that the HSI is the most suitable thermal stress index, although it stilldoes not completely explain tropical heat stress conditions.This thesis also provides preliminary guidelines for preventing or at least reducingthe death rate and the costs of morbidity related to heatwaves. The guidelines coverrecommendations for policy-makers, architects and builders, managers and caregivers andthe elderly