NBC Filter Performance

Abstract : This document summarizes the ability of nuclear, biological and chemical (NBC) filters to remove chemical biological aerosols and vapors. The NBC filtration systems consist of a particulate filter to remove liquid and solid phase toxic materials, and a vapor filter to remove gas phase toxic materials. The particulate filtration stage consists of HEPA media, which provides 99.97% filtration efficiency. The vapor filtration stage provides high capacity removal of all CW agents at efficiencies of >99.999% for the super-toxic nerve agents. This stage consists of activated carbon impregnated with materials that react with those agent vapors that are ineffectively adsorbed by the activated carbon. The NBC filters also provide protection against a wide range of toxic industrial materials (TIMs). These effectively filtered TIMs include those in aerosol/particulate form and vapors that exhibit either acid properties or possess a vapor pressure of less than about 10 mm Hg at the filter temperature. Particulate filtration performance of NBC filters is verified using a test aerosol of a 0.3 micro m particle size. Vapor filtration performance is verified by determining the agent filtration of the adsorbent through "life" testing with a variety of performance- limiting agents, as well as filter "life" testing to verify acceptable efficiency and capacity.