[A study for the practical use of the mask fitting tester].

The standards require replaceable dust respirators to be designed so that the wearer can easily check facepiece-to-face fitting at any time. The common practice adopted is an air leakage examination between the facepiece and the face in a negative pressure created by sealling-off inhalation area and breathing-in (called "a negative pressure method"). This method offers only subjective testing made by the wearer himself or herself, no objective testing is possible by the third party including supervisors and hygiene staff. Accordingly, we conducted the practical use test of the Mask Fitting Tester (Model MT-02, Roken type) by letting wearers to use the tester at a sanitaryware plant where workers are well instructed for how to wear respirators and also respirators are used in good care and maintenance. In addition, a questionnaire survey was conducted to investigate how wearers perceive the practical use of the Mask Tester. The following are the conclusions of the study and the survey for the practical use of the Mask Tester. 1) At the first fitness test, when examinees wear the respirator as in the usual manner without given particular instructions, 50% of examinees are found unachieved with the leakage rate of the desired value of 5% of less. 2) All the examinees unachieved were instructed by hygiene staff followed by fitting test to check their leakage rate until they pass the desired value. After repeating this three times, there were no examinees found unachieved. 3) 88.2% of these examinees could achieve the desired value only by adjusting headbands and correcting the position of facepiece under instructions.(ABSTRACT TRUNCATED AT 250 WORDS)