Evaluation of the effectiveness of personal cooling systems for use in industry

This project was established to examine the utility and effectiveness of personal cooling systems as a possible means of combatting the risk of thermal stress in a variety of industrial situations. Surveys showed that thermal problems could arise both from external sources or as a results of waste (metabolic) heat generated from physical activity. It was also recognised that high air temperatures were not a necessity for thermal stress and that factors hindering heat loss such as high humidities or a vapour occlusive clothing barrier could also create potentially hazardous conditions. Personal cooling systems were identified which utilised four different cooling media: air, water, water-ice and solid CO2. Seven personal cooling systems incorporating these were evaluated both for physiological effectiveness and for practical utility. These systems comprised three air-cooled, a liquid cooled, two water-ice cooled and a dry-ice (COJ cooled garment. All of the air-cooled devices were also intended to provide respiratory protection, presenting clean filtered air to the wearers’ breathing zones. All the systems tested produced some physiological benefit although in some instances this was limited. For example, although initially effective the ice-based systems lost effectiveness as the cooling effect deteriorated with the ice melting. However, the physiological benefits were often largely negated by the impact of clothing design on comfort and, more importantly, mobility. These factors could well have a significant impact on their acceptability for industrial workers. Despite these difficulties, industrial staff at a metal refinery successfully used and benefited from cooling provided by water-ice jackets during a brief trial. The findings from these studies have been used to produce guidelines both for manufacturers of cooling systems to enable them to design better, more acceptable, garments and for potential purchasers to guide them in identifying which type of system is most suitable for their purposes. “”