Contact pressure study of N95 filtering face-piece respirators using finite element method

Respirators protect workers from hazardous airborne particles. It is important to evaluate respirator comfort and fit for all workers of diverse anthropometry as contact pressure plays a vital role. This paper presents the procedure and results of studying contact pressure of N95 filtering face-piece respirators (FFR) by using a finite element method. Finite element models of respirators and headforms have been improved based on a previous study. The headform model contains a skin layer, muscle layer, and bone layer. The whole facial area is divided into four parts (two areas for cheeks, one area for upper forehead, and one area for chin). Two N95 FFR models (one is one-size-fits-all and the other FFR has two sizes, i.e., small and medium/large) are used to simulate the interaction between the respirator and the headform. The results show that the respirator with two sizes provides better contact pressure distribution than the one-size-fits-all respirator. It has also been shown that the one-size-fits-all respirator works well for the large, medium, and short/wide headforms, but there are indications of potential leakages for the small and long/narrow headforms. For the respirator with two sizes, the medium/large size respirator works well for the large and long/narrow headforms, while the small size respirator works well for the medium, small, and short/wide headforms. The medium/large size respirator has potential leakages for the medium headform. Furthermore, the N95 FFR with two sizes has a more uniform pressure distribution than the one-size-fits-all respirator. Future studies are needed to validate these observations with human subjects. © 2010 CAD Solutions, LLC.