Evaluation Indice Of Human Heat Strain In Hot Based On Thermal Balance Theory

High temperature is one of the main occupational hazards in manufacturing industries.The hot and humid environment can cause heat injuries for workers,which seriously affects the workers'lives and work efficiency.At present,the domestic and foreign scholars focused on the cooling mechanism,cooling equipment and the thermal comfort evaluation indice,etc.Thus,how to evaluate the heat strain scientifically and effectively which can prevent workers from heat stress is the main research filed to domestic and foreign scholars.Based on the comprehensive analysis and research into the evaluation method and index of the heat strain,the human heat storage rate is selected to characterize the transfer process of human heat and moisture under the hot and humid environment Thus,the human heat storage rate and CHS(cumulative heat storage)were established to evaluate the heat strain.Then,through the data of real-body wearing comparative experiment which is conducted in the climate cabin that simulates the hot and humid environment in the Faculty of Construction and Environment of the Hong Kong Polytechnic University,the new indices are verified by the changes of human physiological state.Meanwhile the validity and accuracy of new indexes are verified by PSI(physiological strain index),core temperature,heart rate and skin temperature.The comparison results shows that:(1)Single indice,such as core temperature,heart rate,skin temperature,can only evaluate heat strain from one single physiological response.(2)The effectiveness of PSI,which can evaluate the human body subjected to heat stress intensity is validated.PSI can characterize that human physiological changes along with exercise intensity,but it can't reflect the change of heat storage of human body.(3)By comparison,it proves that CHS and PSI have a good linear relationship(r~2=0.835).CHS can better assess the heat strain in the stationary state,however,for its range CHS cannot be used to evaluate directly.(4)The improved CHS resulting from the non-dimensionalization changing has a better linear relationship(r~2=0.9254)with PSI,and the evaluation range is between 0~10.The improved CHS can directly evaluate the human body subjected to heat strain.Compared with PSI,the weight of CHS has significance in theory,rather than human endowment.Through the method of thermal theory combined with experimental data,the evaluation system and the evaluation index CHS of the heat strain are built.On the one hand,CHS can help us understand the changes of human physiological state more clearly.On the other hand,it can reflect the changes of thermal balance,which can provide the basis for suffering from the heat strain when working in hot environment.