Study of protective properties of half-masks respirators used by miners

Purpose. To define coefficient of protection of filtering respirators with elastomeric half-masks PR-7 in conditions of coal mines. Methods. Antidust respirators applied at mining enterprises of Ukraine were tested for determination of their protective efficiency. Findings. As a result, it was found that the protection coefficient of the provided half-masks is in the range from 5 to 34. The main reasons of half-masks protective properties deterioration are poor insulating properties of half-masks, their design defects, improper use, application of respirators in case of unacceptably high concentration of dust and also lack of standard sizes of half-masks for operating. Originality. It has been established that the value of protection coefficient in case of dust content growth due to increasing dust coarse fraction, which in combination with high moisture will quickly fill gaps on an obturation line and thereby will reduce penetration in under mask space of the half-mask. Practical implications. The received results indicate that the half-mask respirators of the PR-7 type of samples 1 and 4, used by miners, allow to provide effective protection according to DNAOP 0.00-1.04-07 “Regulations of selection and use of personal protection equipment of respiratory organs”, in case of their use up to maximum allowable concentrations 12.