Model-Based Assessment of Heat Wave Impacts on Occupational Heat Stress and the Economic Sustainability of Mitigation Measures

Increasing exposure of workers to heat-wave conditions and occupational heat stress highlights the need for methods that integrate the assessment of thermal working conditions with the selection of sustainable and economically justified protective measures. This article proposes an integrated technical–economic framework for assessing heat stress during outdoor work, based on the Wet Bulb Globe Temperature (WBGT) index and dry-bulb temperature td. The framework also enables the determination of cost-effectiveness domains for selected protective solutions. Three environmental scenarios and four variants of meteorological conditions were analysed, representing different combinations of solar exposure, humidity, and air movement. The calculations assumed an 8-h work shift, including 4 h during which conditions exceeded the adopted criterion, a 10-person work team, and a labour cost of EUR 30/(worker·h). The preventive measures analysed included organisational measures, shading, local mechanical cooling, combinations of technical solutions, and a separated cooled work zone; PCM cooling vests were considered solely as a supplementary measure. For each variant, avoided losses, implementation costs, economic balance, the equivalent number of avoided work stoppages, and the minimum number of avoided work stoppages required to achieve cost-effectiveness were determined. The cost-effectiveness threshold ranged from one avoided work stoppage for shading, through three avoided work stoppages for mechanical cooling and the technical package, to eight avoided work stoppages for a separated cooled zone. The proposed approach constitutes a modifiable framework for selecting measures to mitigate the effects of heat stress under different climatic, organisational, and cost conditions.