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UV-C Technology: Healing Hospitals
It’s a tragic irony that hospitals, specifically designed to be centers of healing, can be among the most hazardous places to people’s health in the United States.
Health-care-associated infections, also known as hospital-acquired infections (HAIs) and nosocomial infections, kill more people than AIDS, breast cancer and automobile accidents combined.
What’s more, according to the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), antibiotic-resistant infections are on the rise. Some are even termed “superbugs” because they are immune to most drugs and can spread quickly through the hospital environment.
As these superbugs become more and more prevalent, hospitals will need to focus not only on treating them, but, more importantly, on preventing them in the first place.
In a new article by Forrest Fencl of UV Resources discusses how Ultraviolet Germicidal Irradiation (UV-C) can help destroy these microorganisms to combat HAIs.
According to Fencl, one of the oldest, and yet, underutilized methods of disinfecting health-care settings is UV-C energy. UV-C technology destroys all microorganisms. In fact, science has yet to find one, including superbugs, resistant to the destructive effects of the 254-nm germicidal wavelength.
Fencl notes that UV-C can be installed inexpensively throughout healthcare facilities by 1) using upper-room units for interior spaces, 2) lamps in HVAC ducts and exhaust systems for airstream disinfection and 3) in air handlers to disinfect airstreams, coils, air filters, drain pans and other potential reservoirs for microbial growth and proliferation.
In his article, Fencl describes upper-air/room and HVAC applications, leaving air stream disinfection for a separate discussion.
UV-C in Upper air/room:
Upper-air/room systems are installed in communal spaces, such as in patient and waiting rooms, corridors and break areas to interrupt the transmission of airborne infectious agents. Airborne droplets containing infectious agents can remain in room air for 6 min or more. Upper-air UV-C fixtures can destroy those microbes in a matter of seconds and they operate 24 hours a day for continuous control!
Fencl notes that UV-C has been shown to be effective against virtually all airborne viruses and bacteria, including chickenpox, measles, mumps, tuberculosis (TB) and cold and flu viruses.
With the recent measles outbreak across the United States, incorporating the technology into schools and especially daycare centers is another timely application, in addition to hospitals.
UV-C in HVAC systems:
In HVAC systems, mold and some bacteria can grow in damp areas around cooling coils, drain pans, plenum walls and filters. This environment also keeps viral agents from dehydrating, keeping them viable for much longer periods of time. Growth of microbial deposits also leads to coil fouling, which increases coil pressure drop and reduces airflow and heat-exchange efficiency.
As performance degrades, so does the quality, [amount and pressurization capability] of air supplied to conditioned spaces. Here’s more about how UV-C can restore airflow levels and reduce energy use and maintenance.
According to Fencl, hospital codes call for high-efficiency filters to be located downstream of cooling coils, where they can become damp and even wet from saturated air. As a result, air filters are considered a growth medium for mold and bacteria and a reservoir for infectious-disease agents.
A 360-degree UV-C system installed downstream of cooling coils will destroy all microbes in and on both the coils and filters. He notes that in a “common” coil-irradiation system, a 360-degree lamp also will kill up to 35 percent of infectious agents moving through the air!
Safety and Handling
Fencl stresses that UV-C’s superb disinfecting qualities can assist any healthcare institution in its control and elimination of hazardous microorganisms. However, he presents a few installation best practices that must be kept in mind when incorporating UV-C technology in a hospital setting, including
- To prevent the disruption of pressure relationships and the escape of unfiltered air when installing UV-C, the opening of air-handler fan-section doors should be coordinated with floor nurses so all room doors can be closed beforehand.
- UV-C exposure is an effective means of destroying microbes on filter-media surfaces. Glass-media filters are compatible with UV-C, while synthetic-media filters are not.
- Facility staffs require training for proper inspection of UV-C systems. Controls should be installed so UV-C systems turn off when air-handler doors are opened. Eye and skin protection are needed in the presence of UV-C light.
- UV-C lamps are very similar in construction to fluorescent lamps and, therefore, contain trace amounts of mercury. The use of encapsulated lamps is recommended to prevent air-handler contamination should a lamp break. Like fluorescent lamps, UV-C lamps should be replaced and recycled annually.
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