Summary of the Technology Evaluation Report by the EPA and NHSRC.
Survival rate of microorganisms after in-duct UVC exposure (one pass). A Sanuvox BioWall 50 was mounted parallel to the airflow in a 24’’x 24’’ test ventilation duct to maximize contaminants’ contact time with the lamps. Air flow rate through the duct was tested at 1970 CFM. Pathogens were grown, then aerosolized in different particle sizes (avg 2 microns) upstream of the tested unit (BioWall 50). UVC Lamps were operated for a standard 100 hours prior to the test. In-duct test protocol is according to procedures of the ANSI/ASHRAE Standard 52.2-1999, Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size 1. Results are shown as a ratio of control, which corresponds to samples collected upstream of the operated unit (vs downstream after UVC exposure).
Microorganisms were selected because their resistance to UVC is similar to known human pathogens. B. Atrophaeusis a sporulating bacterium more resistant to UVC, S. Marcescens is a vegetative bacterium, and MS2 bacteriophage is a virus that infects bacteria. By comparison all microorganisms tested are more resistant to UVC than SARS-CoV-2, the virus responsible for COVID-19 2, 3.
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