ABSTRACT
Objective In order to provide important theoretical basis for further improving design of DC-7/7A high altitude partial pressure suit and FTF-2 air ventilation suit (named as A suit and B suit), the performance of ventilating heat dissipation of DC-7/7A and FTF-2 was studied. Methods Five healthy volunteers were enrolled to took participate in A group and B group tests. Environmental weather conditions for A and B suits were set at Tdb 40℃ and 45℃,rh 45% and 40% respectively, and the test time was 90min and 120 min respectively. Results During the test for A group and B group, Ts ranged from 31.5℃ to 34.5℃ for human comfort. Average skin temperatures of the lower part of the body were from 33.1℃ to 33.8℃. Skin temperatures of the legs did not obviously change or slightly lowered. Heart rate showed an increase of 12 beats/min and 14 beats/min. Sweat quantities were measured to be 0.288?0.056kg/1.5h and 0.445kg?0.077 kg/2h respectively. Evaporation rates were 77.4?3.6% and 84.2?2.4% respectively. Subjective uncomfortable sensation was more obvious as test time went on. Conclusion The results of the ventilating heat dissipation for both groups were quite good, but the findings suggested that the number of the ventilating holes for some important sites should shall be re-considered. Pilots wearing A group and B group with ventilation function would still suffer from mild heat stress and obvious subjective discomfort in hot enviroment.