Evaluation of Two Liquid Cooled Prototype Vests Through Human Subject Testing

First responders are specialty teams who are trained to work in toxic environments to assess and diffuse the threat. They have to wear specially designed Personal Protective Ensembles (PPE) that is impermeable to liquids and gasses. Microclimate inside PPEs gets hot and humid, rapidly rendering it uncomfortable and often hazardous to work longer than 30 minutes at a time. Providing active cooling is one way to extend the time spent in PPEs. Two water-cooled prototype garments were developed at our department. This study focused on the evaluation of the prototype cooling garments using human subjects, performing simulated tasks in an environmental chamber. Both physiological and perceptual responses were considered to understand the garment's effectiveness in providing cooling relief as well as the user acceptance in terms of ease of use, comfort and perceived effectiveness. The subjects' perception of cooling relief generally agreed with the physiological data. The two prototype cooling vests positively affected skin temperatures, sweat rate, microclimate temperature, humidity, perceived temperature and perceived humidity. Both physiological and perception data indicated there were no significant and consistent differences between the two cooling vests. The subjects perceived the prototype cooling garments to provide effective cooling, to be attractive and practical overall.