Performance Evaluation of a Demand-Valve, Power-Assisted M17A1 Protective Mask

摘要

A modified Balke treadmill test was used to measure the physical performance of men walking in a hot (105F dry bulb, 77F wet bulb) room under the following conditions: (1) bareheaded, (2) wearing a standard M17A1, (3) wearing an M17A1 blank (low resistance), and (4) wearing an M17A1 mask with compressed-air, power-assisted breathing. The M6A2 hood was always worn with the mask. Using nonparametric analysis on ranked data, a statistical difference was found in the length of time the men walked in a comparison of the bareheaded condition with the M17A1 mask, the bareheaded condition with the power-assisted mask, and the blank M17A1 mask with the standard M17A1 mask. The heart rate data taken at the 10th test minute indicated no difference in heart rates under the four masked conditions. The heart rate data taken at the termination point of walking indicated no difference between masked conditions and hence that the men were putting out the same amount of effort for each test. Subjects were not severely heat stressed by this test. The conclusion was that the M17A1 mask with the demand-valve, power-assisted unit did not favorably increase performance in short-term, high-intensity work in the heat. (Author)