328 Evaluation of a novel respirator fit testing apparatus (Sibata’s MT-11D): pilot study

Performance of a respiratory protective device largely depends on how well this device fits the wearer. Therefore, quantitative fit testing of particulate respirators is very important for achieving the intended protection level. Millions of fit tests are conducted by workers every year using a US OSHA-accepted standard protocol and a PortaCount instrument (TSI Inc, Shoreview, MN, USA) which measures a respirator fit factor. Several alternative fit testing instruments have been recently developed. Among them is an MT-11D (Sibata Scientific Technology Ltd, Tokyo, Japan), The novel instrument, like the PortaCount, utilizes the condensation particle counting principle but it features an advanced saturation chamber and has other design advantages over the PortaCount. In this pilot study, the newly developed apparatus was evaluated against the PortaCount (utilized as the reference instrument) using the standard fit testing protocol. The evaluation was performed with three types of respirators – an N95 filtering facepiece respirator (FFR), P100 FFR, and half-mask elastomeric facepiece, each represented by three different models and manufacturers and donned on 6 subjects. The comparative testing and analysis showed a good correlation between the fit factors measured by the two instruments. It was concluded that the MT-11D is capable of identifying an inadequate fit of the tested respirators with high sensitivity and specificity. The novel fit testing apparatus demonstrated an acceptable performance and thus can be successfully deployed for the quantitative respirator fit testing.