Mobile high-efficiency-filter air cleaners

Mobile high-efficiency-filter air cleaners (MHEFACs) are freestanding air filtration and recirculation systems used to supplement poor ventilation or to compensate for a lack of ventilation in general-use and high-risk areas of healthcare facilities. These devices are primarily used as an engineering control to reduce the concentration of infectious tuberculosis (TB) droplet nuclei in the room air. This Update supplements our October 1995 Evaluation (Health Devices 24[10]) of these devices, in which we evaluated 14 MHEFACs from 10 manufacturers. In the current Update, we evaluate 3 additional MHEFACs from 2 additional manufacturers. We also present update information for the previously evaluated units. Unless otherwise specified, we tested the new units against the same criteria and using the same test methods as those detailed in our October 1995 Evaluation. For brevity, we have not reprinted criteria or test methods that were identical to those used in the original study. In the introduction below, we briefly describe the purpose and use of MHEFACs, focusing on the application for which they are primarily intended: controlling the spread of TB. For more detailed information about this technology, the environments in which MHEFACs are used, and the factors to consider when selecting this type of device, we encourage readers to refer to the following items in the October 1995 issue: The Clinical Perspective, "The Resurgence of Tuberculosis-From Old Problem to New Menace." The Clinical and Technical Overview, in which we discuss the mechanisms of airborne infection and describe and compare some of the controls used to reduce the incidence of such infections. The Guidance Section, "Issues in Selecting, Purchasing, and Using Mobile High-Efficiency-Filter Air Cleaners." The supplementary articles, "The Wells-Riley Equation," "Airborne infection Control Terms and Abbreviations," and "Air Mixing and Airflow Rates." Descriptions of the newly evaluated units, along with our test results and ratings, are presented in individual Product Profiles following the introduction. Following the last profile, we present a comprehensive Conclusions section that details how the newly evaluated units compare with the previously evaluated ones.