| Summary: | Objective is to study efficiency of a complex protective device including coefficients of penetration and suction of aerosols for dust half-masks of various designs. The half-masks were tested experimentally on specially designed laboratory stands with the help of volunteer-testees; the tests included specifications according to EN 149, EN 352-1, ISO 6942. The studies have demonstrated that a complex protective device for workers is rather efficient providing average coefficient of suction being 1.5% that is almost by 30% less than the values of standard filtering respirators of similar protection class. Noise attenuation within the range of 4000 – 8000 Hz is from 19 to 26.7 dB; within the range of speech frequency (0.5÷2.0 kHz), acoustic efficiency is up to 8÷16 dB helping preserve the possibility of communication and timely reaction to warning signals. Use of thermal protecting elements makes it possible to reduce temperature of head heating by 80% comparing to the results obtained without the protective device application. The developed balaclava with the built-in dust respirator and hearing protection devices may be used in the context of the corresponding filter class up to 12 MAC in terms of the most hazardous aerosols, when noise level is up to 14 dB within 2000 – 8000 Hz frequency range; moreover, it provides slow temperature rise up to 2 ºС per minute.
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