Solar heat load on man. Review of different methods of estimation

Different methods have been compared for the estimation of solar heat load on man. The comparison comprised several methods based on the calculation of absorbed solar radiation and one method for calculation of mean radiant temperature (Mrt). Regression analysis was carried out for predicted values and values calculated for a vertical cylinder, assumed as an analog model of a standing man. Regression of mean skin temperature, measured in 10 subjects exposed to solar radiation under a variety of climatic conditions, on predicted radiant heat load was also analysed. Mean skin temperature correlated best with Mrt, accounting for more than 50% of the variance. The results indicated that three methods provide a realistic estimation of the radiation heat load, whereas some methods show deviations of several hundred per cent.