A Test Bench for Replicating Human Breathing: Evaluating Thermal Effects of N95 Filtering Facepiece Respirator Leaks – Preliminary Findings

Following the COVID-19 pandemic, it seemed important to develop alternative methods for verifying the fit of a filtering f acepiece respirator (FFR). I nfrared technology, promising in the assessment of the fit of a F FR, still requires a thorough study of the thermal effect of a N95 FFR leak. This pilot study aims to design a test bench capable of replicating human breathing as faithfully as possible, focusing on three aspects: breathing airflow, breathing temperature, a nd particle generation. The humidity aspect is not replicated in this study. To achieve this, the ASL 5000® Breathing Simulator, a heating chamber, and a HEPA filter were employed. These three aspects were validated through various tests on the test bench. The primary objective of this test bench is to assess the thermal impact of different leaks from an N95 FFR on two different test devices designed for this study: a flat model a nd a Static Advanced Headform (StAH). The thermal impact of the leaks was captured using an infrared (IR) camera. Additionally, a particle counter, the PortaCount Instrument, was integrated into the test bench to quantify N95 FFR leaks and was used as a reference. In the near future, this test bench will enable the development of methods to locate and quantify N95 FFR leaks, which will subsequently be applied to human subjects.