Research On Human Heat Tolerance Under Extreme Hot, Humid And Low-oxygen Environment

With the progress of modern society, the security of the operation is increasingly concerned, especially an extreme hot, humid and low-oxygen condition. In this field, a key point is to investigate the variation trends of physical and psychological indexes of human body in the presence of extreme hot, humid and low-oxygen environment. Meanwhile an effective evaluation method to assess heat state of human body and improve existing standard assessment systems is necessary. Main aim is to prevent and decrease the harm of heat exposure on human body. In this thesis, Experimental investigations of heat tolerance capability of human bodies were carried out under different extreme hot, humid and low-oxygen conditions, and a related assessment method was performed.A chamber with an extreme hot, humid and low-oxygen condition was designed. The inside dry bulb temperature was varied from 34℃to 42℃, relative humidity from 50% to 100%, and volume percentage of oxygen from 13.1% to 21%.Through lots of experiments and tests, mathematical models were established on the relations between human body's heat tolerance and WBGT value, volume percentage of oxygen and intensity of labor. The maximal heat tolerance limits of human body under different stream conditions can be predicted by the models.Meanwhile, the variation trends of physiological, psychological and cognitive indexes of the human bodies were obtained. The utmost heat tolerance limit of human bodies under different stream condition and related parameters were determined. The influences of the parameters of different conditions on heat tolerance of human bodies were analyzed.An improvement of a physiological stress index PHSI was carried out to assess the ranges of dangerous heat exposure areas and safety areas for human bodies under conditions of different oxygen volume percentages. Combining the index of action function and index of physical strength, new indexes of work efficiencies under different extreme hot, humid and low-oxygen conditions were obtained. Scopes of four types of work efficiencies were divided. Whole results from this research can give different operations empirical references, improve preventable alarm systems and safety and validity of operation, and provide reliable data to instruct reasonable and safe operations standard for stream operation conditions..