Evaluation of ISO 7243 and Other Indices Relating to Application of Mist Evaporation Cooling in Hot Environments to Reduce Heat Stress on Workers

摘要

Mist evaporation cooling could be a low-cost means to reduce heat stress on workers in hot environments where standard air conditioning is impractical. ISO7243 and JISZ8504 standards, which regulate the rest rate for such workers, are based on the natural Wet Bulb Globe Temperature(WBGTn). Mist evaporation takes place at nearly-constant wet bulb temperature. Calculations confirm mist cooling would yield almost no change in WBGTn. Indices based on thermal load on the body including PMV, ET* and 2-node Pierce model all show mist should yield improvement for typical workers. This suggests the standard is not suited to correctly evaluate mist cooling.