The United States Department of Energy (USDOE) is considering adoption of new test specifications and new test techniques for quality assurance testing of nuclear grade high efficiency particulate air (HEPA) filters. Proposed new filter test specifications require penetration measurements to be made at a particle diameter in the range from 0.1 μm to 0.2 μm rather than at a particle diameter of 0.3 μm which is currently required. The new specifications are aimed at making penetration measurements at or near the size of maximum penetration for the current generation of nuclear grade HEPA filters. The new test specifications provide a high estimate of filter penetration relative to the predicted penetration of field challenges in terms of aerosol size and aerosol density. This conservative estimate is required to assure that USDOE air cleaning systems adequately protect public and worker health and the environment in the event of unplanned release of hazardous materials.
Operational evaluation of a high flow alternative filter test system (HFATS) developed for the USDOE by Los Alamos National Laboratory is currently being completed. Interim results of this evaluation and results of laboratory and full-scale evaluations demonstrate that the HFATS is capable of providing measurements of filter penetration at specific sizes over the diameter range from ∼0.1 μm to ∼0.4 μm within the operational requirements of the USDOE Filter Test Facilities.