Hodnocení spolehlivosti lidského činitele v závislosti na vlivu tepelné pohody

Abstract

The subjective feeling of thermal comfort is determined by microclimate conditions that influence a human in a work environment, and the work environment belongs to the basic factors influencing the level of occupational safety and hygiene. The aim of the thesis was the determination of a response of selected physiological factors, the subjective assessment of subjects in an environment with a non-uniform radiant-convective load at low energy expenditure work, and the determination of an influence on the work performance of these persons. For 1 hour, 24 women at the age of 20 to 23 were exposed to a non-uniform radiant-convective load in a climate chamber at computer work; their work performance was observed in the course of playing computer games. Each subject underwent 24 experiments. Measurements were divided according to the final temperature of spherical thermometer tg into 3 stages. A difference between the radiant temperature due to wall radiation and the temperature of spherical thermometer Δ (trA–tg) moved in individual experiments in the range from -9 to +34 °C. In all the stages, the air flow velocity approximates the value of 0.25 m • s-1, the relative air humidity moved in the physiological range from 30 to 70 %. The thermal resistance of clothing was chosen so that thermal conditions in individual stages might correspond to the optimal thermal and humidity conditions for the given energy expenditure. Microclimate conditions, heart rate and skin temperature were continuously recorded by a PC. Thermal feelings of subjects were expressed in a seven-point scale ranging between -3 and +3; the centre being the optimum. For statistical assessment, the correlation and regression analyses were used. Any significant differences in values of neither change in heart rate, nor change in body core temperature were found. This corresponds to the fact that the microclimate conditions moved in the range of optimal temperatures depending upon the thermal resistance of clothing and upon the energy expenditure. The average temperature of skin moved in the physiological range from 31 to 34 °C. Subjective feelings were evaluated in a broad range of the evaluation scale; at tg = 19 °C the environment was perceived as moderately cool to cool, in the cases when tg = 25 °C, the environment was perceived as moderately warm to warm. It was found that on the whole, the subjects were satisfied most with conditions chosen in the framework of the third stage, when the temperature of spherical thermometer was the highest, tg = 25 °C. In the course of assessment of work performance, the elimination of influence of repetition failed, the results had to be recalculated by means of the determined regression equation. The corrected values were tested by means of dispersion analysis, and results did not confirmed any influence of non-uniform radiant-convective load in the framework of created microclimate conditions on the mental performance of subjects either in individual conditions in the framework of a stage or between the individual stages.