Background
This product study evaluates the effectiveness of the
UV light technology has been successfully used for the disinfection of drinking water for years. Applications for air disinfection with the use of UV light technology include: commercial air treatment in hospitals, clean rooms, meat packing plants, bakeries, dairies, breweries, bottling plants and large commercial HVAC systems.
ORGANISM:
Serratia marcescens (ATCC 14756) was chosen as the test bacterium. The distinctive red colonies made it easy to evaluate from any background organisms. A raw test suspension of the organism of approximately 95,000 CFU/ml was used. As dispersed into the test system, this suspension yielded bacterial counts of 269 CFU/ft3 @ 500 ft/min airflow and 107.5 CFU/ft3 @ 1000 ft/min airflow. (CFU = Colony Forming Units)
TESTING STRUCTURE:
An 18” x 18” galvanized air duct, 38 feet long was constructed as the test chamber (see Figure 1). A fan was mounted at the exit end of the chamber and the treated air exhausted to the outdoors. To reduce contamination of the intake air, all air intakes on the exhaust side of the building were sealed. The exhaust fan was equipped with a flow adjustment to allow for adjustable air speeds measured in feet per minute (FPM) through the duct.
TESTING AIRFLOW RATE:
The airflow rate through the ductwork was adjusted to two nominal velocities of 500 ft/min and 1000 ft/min. The airflow velocities were measured at the center of the duct at the intake end of the test duct.
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