Developing a hybrid cooling vest for combating heat stress in the construction industry

Many frontline workers in the Hong Kong construction industry have to perform physically demanding work under hot working conditions, which could reduce work efficiency and time and increase the occurrence of heat cramps, heat exhaustion, and heat stroke. This study aimed to develop a hybrid, new cooling vest to combat heat stress in the construction industry. Following the functional clothing design process, a problem identification was conducted. Preliminary ideas were formed through the analysis of available types, research, a survey, literature review, and brainstorming. The design was refined through the use of desirable phase change material packs, fans with high wind velocity/long duration, and fabrics with thin, vapor-permeable, wind/water/abrasion-resistant properties, and UV protection, as well as clothing ergonomic design that considers fit, mobility, convenience, and safety. The desirable thermal functional performance in the new cooling vest was previewed through a computer-aided design platform S-smart system. The design criteria were established and a prototype was developed. The environmental chamber testing results showed that, in a hot environment, the mean skin temperature (35.8℃ vs. 36.59℃), heart rate (110 beats/min vs. 116 beats/min), and core temperature of the subjects with the new cooling vest were significantly lower than those with the control (without the new cooling vest ). A significantly longer exercise time was obtained with the new cooling vest compared with the control (22.08 min vs. 11.08 min). Significant improvements in levels of coolness, dryness, comfort, and physical recovery were observed with the new cooling vest. Results suggest that the new cooling vest can reduce the thermal stress of construction workers and improve their work performance and comfort.