UVC is a powerful technique for disinfection that uses nothing but high-frequency light. This makes it easy to implement in a variety of different settings like labs, hospitals, and even homes. However, UVC radiation can be dangerous to people, because the same high wavelengths of light that kill bacteria and viruses can also cause burns and eye damage.
One of the settings where UVC can be very useful is in a hospital. This article describes some of the research about using UVC in this setting, specifically how it works, much UVC is needed and what are some of the challenges of using UVC to disinfect a hospital room.
How does UVC Disinfection Work?
UVC disinfection systems rely on the fact that UVC is the highest energy and highest frequency of ultraviolet light. We encounter lower frequencies like UVA and UVB in our day to day lives through sunlight, but the atmosphere filters out almost all of the UVC.
High energy radiation can alter the genetic material of cells and make it impossible for them to function and reproduce, which eventually kills them. This is what’s happening to your skin cells when you get a sunburn, and it happens to bacteria and viruses too. When implemented properly, UVC systems can kill up to 99% of pathogens.
How Much UVC Is Needed to Disinfect a Hospital Room?
A study published in June 2020 attempted to answer this question by using a radiometer—a device that measures UV radiation—in different areas of a burn ICU. Many hospitals already use UVC systems, this helped the researchers get a general idea of how much UVC actually strikes different parts of the room.
They found that the amount of radiation in a room can vary greatly depending on where you are relative to the light source. The closer you are, the more radiation. However, there are other mechanical factors at play as well. For example, objects can cast shadows and obscure UVC light, meaning that even those places that are close to the light may not be getting radiation. In fact, objects closer to the light will cast longer shadows.
UVC systems only work when the UVC light actually hits the object. Even small shadows caused by texture can make it less effective. This is one of the drawbacks to using it in a setting like a hospital. It can be difficult to implement the system in a way that hits all surfaces. A solution to the problem of shadows is the VX-One UVC device which has a special designed wings with mounted UVC lamps to radiate beyond shadows. The special design enables to set an optimal angle to hit all sides of the object in its path.
As far as how much light, it’s difficult to determine a precise amount of light to kill a certain number of bacteria. This is because light works a bit differently than other forms of disinfection (like bleach or other cleansers). Light disperses in all direction from the light source and bounces around on different surfaces, so it’s difficult to determine if a dose has been made.
However, the study also experimented with validating commercial disposable indicators that change color when exposed to UVC light. These are a great way to see if a spot is getting adequate UVC exposure. And they’re inexpensive. The authors of the study recommend putting these indicators in questionable areas (for example, shadowed areas) to make sure that they are getting an adequate dose of light.
Benefits and Drawbacks of Using UVC Radiation in Hospitals
The best benefit to using UVC radiation for a hospital room is that it works very well. As long as surfaces are exposed to the light, it will kill the pathogens. It’s also extremely cost and labor efficient. Once a system is implemented, it doesn’t cost much more than the price of electricity to keep it going. And there is virtually no labor involved compared to deep-cleaning.
Some drawbacks are the difficulty in getting it to hit all surfaces of a room, as well as the potential to harm people if used incorrectly. UVC also requires comprehensive safety training for those operating the system and those who are going to be around it. This minimizes the risk of exposure. The VX-One motion detection sensors and sound alarms provide several layers of security to minimize the risk of UVC exposure.
Despite the few drawbacks which devices as VX-One address, overall research supports using UVC in hospital rooms. Hospitals have a high turnover of people, and most people in a hospital are either ill already or especially vulnerable to illnesses, so hospital disinfection is paramount. This is especially important during the current COVID-19 pandemic.