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UVGI: The IAQ technology that cried wolf?
Is the promise of Ultraviolet Germicidal Irradiation (UVGI) truth or hype?

By Matt Stansberry (Ask Matt your questions regarding this topic or other Tech to Watch topics)

What if a technology promised to reduce disease in the U.S., save billions of dollars in health care and insurance, and cut down on lost work time? These are some of the promises being made by Ultraviolet Germicidal Irradiation (UVGI). By applying UVGI to HVAC systems facility executives may be able to eliminate a vast majority of harmful microorganisms and improve IAQ.

Would you believe that the technology is over 70 years old? Scientists have used UVGI to sterilize biological contaminants for decades. So why is a technology developed in the 1930s struggling for market acceptance? Part of the reason is misrepresentation from entrepreneurs who want to make a quick gain.

In the wake of the anthrax and mold scares of the last few years, people were eager for solutions. Unfortunately, UVGI is not effective against anthrax spores. Also, killing mold does not help people who react to it as an allergen. Dead or alive, mold is still an allergen.

"The next time you see anthrax come up, you're sure to see a rush of people go out there and say 'UV kills anthrax, and if you buy this system it will solve all your problems'. You're not going to be able to do it just with UV," says Tim Kensok, director of IAQ products at Minneapolis, MN-based Honeywell.

According to Dr. Wladyslaw Jan Kowalski of the Indoor Environment Center, Department of Architectural Engineering at Pennsylvania State University, UV disrupts the DNA of microorganisms, including fungi, bacteria, and viruses. It prevents them from reproducing. If they can't grow, they can't cause infections.

"A well designed UV system can eliminate 99% of tuberculosis, 100% of small pox, influenza, SARS, and avian flu. It doesn't have much effect on anthrax spores, but that's not a problem, because anthrax spores can easily be filtered by a high efficiency filter," says Kowalski [See the March 2004 Product of the Month].

There are three basic groups of biological contaminants-mold/fungi, bacteria, and viruses-all of which are susceptible to UV energy. But, the dose of UV needed to affect each group varies. Viruses are the easiest to sterilize, followed by bacteria. Mold and fungi are the hardest to eliminate with UV.

To deal with this variation, UVGI needs to be broken down into two separate HVAC applications. Eliminating biological growth on surfaces requires different methods than addressing airborne viruses and bacteria.

"As the air passes by lamps in the return air system, you have a relatively short time for UV exposure. You're limited to killing the bioaerosols that have a low threshold to UV energy. Bacteria and viruses are susceptible in this application. We would never talk about killing mold in a single path application," says Kensok.

What it takes to prevent the growth of mold is very long exposure times. This is achieved through continuous irradiation on surfaces like cooling coils and drain pans.

With every new technology there is a lag time for awareness; especially in an industry like HVAC where if something works, people are not willing to jump onto the next thing. Big companies like Honeywell have added a lot of credibility to the technology.

"If Honeywell has a product, there must be something real there, as opposed to some of the initial companies that came out with products and no one had ever heard of them," says Kensok.

The other factor that would accelerate the technology's acceptance is a standard from major organizations.

"When you talk to specifiers, they get very concerned that there is no standard protocol," says Lloyd Chapman, market development manager of UV products for Somerset, NJ-based Philips Lighting Company.

According to Chapman, the International Ultraviolet Association (IUVA) is creating an application standard. The IUVA will present the standard to ANSI and ASHRAE and that is where Chapman believes a standard will be published.

Dr. Kowalski is working with the IUVA on that standard. According to Kowalski, it will be the first standard and probably the best one available. He hopes to have a draft available in one year for public review.

The FDA has not yet commented on UV in regards to air or surface disinfection. According to Kensok, the FDA is rarely going to be the first agency to get involved with a new product category. The consensus is that the FDA may act on UVGI once ANSI or some industry group adopts a standard.

Some agencies have acknowledged the use of UV, such as the Center for Disease Control and the National Institute for Occupational Safety and Health. According to Kowalski, the General Services Administration (GSA) has also acknowledged UV. The GSA allows UVGI to be installed in government buildings-but that is about all the group will support. The Federal Emergency Management Association acknowledges UV as an alternative technology for controlling bioterrorism threats.

But at this time, ASHRAE has not yet addressed UV outside of journal articles. The organization has no standard for it, nor does it have plans to write one.

"UV is a viable technology both for bioterrorism defense and for control of indoor airborne diseases. Once we get a standard out there telling people what is acceptable performance, people will begin designing these systems into new buildings and retrofitting old buildings," says Kowalski.