According to Dust Free, anthrax spores can migrate into the hvac system of targeted buildings or residences. And although UV light fixtures mounted in the hvac system will not provide “point of contact” protection from opening a letter containing the spores, there is data to support the claim that UV-C energy can damage anthrax bacteria if the spores migrate onto a surface in the system where the UV-C light is installed.

The distributor is currently working with experts in the bioaerosol field to determine what the optimum installation parameters should be when applying UV-C fixtures into hvac systems to achieve maximum bacterial reduction.

According to Penn State University, the decay rate constant of anthrax in the presence of UV-C light is .000509. The decay rate is an indicator of how quickly the spores are damaged by UV energy. This has led the Dust Free engineering staff to believe that applying enough UV to damage the anthrax spore “on the fly” in the airstream could be difficult.

With this in mind, Dust Free is testing the strategy of placing the Bio-Fighter UV fixtures upstream of high efficiency mechanical air filters contaminated with bacterial spores. The strategy is that since the anthrax spores are 1 to 1.5 microns in diameter, the higher-efficiency air filters will be able to capture 60% to 90% of the spores that could migrate into the ventilation system of a building.

Publication date: 12/10/2001