[Optimal physiological parameters of respiratory tract protective devices]

The studies have been aimed at the evaluation of the effects of the use of purifying and insulating equipment of the respiratory system upon some physiological reactions. Also optimum physiological parameters for the respiratory tract safety equipment have been set up. The value of air flow resistance measured at constant air flow rate of 30 l/min should not exceed 10 mm H2O in the inhaling phase and 4 mm H2O in the exhaling phase. The dead space of the safety equipment should not exceed 150 ml, whereas CO2 concentration in the inhaled air -- 0.4%. The air flow rate should amount to 9 -- 12 m3/h during light physical effort of 48 Watt and 12 m3/h during moderately hard physical effort of 96 W. Air temperature in the facial part should be 19 -- 25 degrees C.