Interlaboratory comparison to evaluate the methodology for determination of the media filtration efficiency against nanoparticles

Current international standards dealing with efficiency test for filters and filter media focus on measurement of the minimum efficiency at the most penetrating particle size. The available knowledge and instruments provide a solid base for development of test methods to determine the effectiveness of filtration media against airborne nanoparticles down to single-digit nanometer range. An interlaboratory evaluation was performed in the framework of the European Mandate M/461 activities, within the Technical Committee 195 of European Committee for Standardization (CEN/TC195). The purpose was to develop a methodology to determine effectiveness of filtration media against air-borne particles in the 3 - 500 nm range. Five different laboratories (Camfil, ETH/Empa, Politecnico di Torino, University of Minnesota, Unifil) participate in the round robin test in order to verify the repeatability and reproducibility of the test method. The qualification of test rig and apparatus was performed prior of the filtration efficiency and air flow resistance measurement tests.Twilled dutch weave wire mesh was chosen to perform the validation filtration efficiency tests so as to ensure high uniformity of the samples being tested by each different laboratory. We present the experimental data with the discussion about their validity.