Despite the increasing number of successful vaccinations, COVID-19 cases are still rampant in almost all parts of the country. It is even interesting to note that a small percentage of people who are fully vaccinated against COVID-19 are re-catching COVID-19. Normalcy seems to be near, but we must prioritize self-care to eradicate this pandemic. We obviously need to do more than washing hands and wearing masks; it is high time we considered disinfection technologies like UV-C lighting to maintain cleaner and sanitized spaces.
Reduced transmission and keeping occupied spaces clean are two major challenges we currently face in minimizing the virus’s spread. People emit water droplets containing the virus into the air by speaking, coughing, and sneezing. Larger droplets may fall fast to surfaces, but smaller ones might float for several minutes and circulate through the air.
The immense benefits of UV-C lighting for disinfecting purposes means we can correctly employ upper-air and HVAC germicidal UV fixtures to disinfect the air in occupied spaces. This is especially important because the virus that causes COVID-19, SARS-CoV-2, is predominantly transmitted via airborne particles. UV-C technology reduces transmission rates dramatically by cleaning the air, which is the primary medium for this transmission.
So, which method is the most effective? Let’s first start, with a basic understanding of how each application works.
Upper-Air Germicidal Ultraviolet (GUV)
It is no news that UV-C rays may damage our skin and eyes if and when we come into close contact with them. Installing upper-air or upper-room UV lamps that release UV-C rays over the heads of occupants of a space will keep them entirely safe. The disinfection of the UV-C light is very effective, despite being directed at the air in a room’s upper region.
Air changes are always ongoing because air normally goes from higher to lower locations in a room. This occurs naturally even without HVAC or fans, although HVAC and fans usually increase the extent of air changes each hour in a room.
We can establish that upper-air GUV fixtures are:
Extremely effective – Proved by several studies in airborne and pathogens, including COVID-19, influenza, and Tuberculosis.
Safe – The fixtures are designed to maintain the UV-C radiation in the upper room.
Runs constantly – Offer continuous disinfection in occupied spaces over the useful long lifetime of the lamp and luminaire.
* Pictures from CDC.
What role does UV play in HVAC?
UV lighting on HVAC equipment has two advantages for the entire system. First, the air that enters and circulates through the building is initially cleansed and cleaned. Second, UV-C eliminates mold and fungi, making the overall system healthier.
In-duct and on-coil UV applications are the two most common UV use for HVAC equipment. The amount of space available may determine the optimal application.
This is how an on-coil system disinfects the air:
*Photo adapted from Regency Lighting
However, HVAC has a number of drawbacks:
Lower transmission reduction — While UV fixtures in HVAC systems disinfect the air, they do nothing to prevent the transfer from person to person within rooms.
Higher energy bills - The extra fixtures on your system may result in increased energy costs.
Slow air disinfection - Upper-air systems disinfect air 20x faster than HVAC.
While the systems can inactivate viruses, they are not 100 percent effective. The virus must be exposed for a specific amount of time and under specific conditions to be inactivated. However, exposure will be limited if the air velocity is too high, and limited exposure may not be enough to deactivate all of the viruses present in the airflow. Dust and moisture in the airflow can also shield the viruses from UV-C light. Also, any buildup of dust or filth on the lamps will diminish light output. Therefore, the construction of the systems must be such that they ensure maximum exposure.
HVAC vs. Upper-Air Germicidal UV Fixtures
Take a quick look at the chart below for easy comparison:
Disinfects and cleans air
Reduces airborne transmission
Continuous disinfection in occupied spaces
Faster air disinfection (up to 750 sq. simultaneously)
UV disinfection in upper rooms and HVAC systems both contribute to a healthier indoor environment. Both are effective air disinfection procedures that may be used continuously, regardless of the number of people in the room. However, only upper-room fixtures are known to limit airborne and person-to-person virus spread.
Most experts recommend installing upper-air germicidal ultraviolet lamps in an occupied space. Check out what the CDC has to say about ultraviolet germicidal irradiation (UVGI). Click here. Let’s not forget that breathing in clean air is now the topmost priority, and we need to take care of ourselves much more than before to stay safe.
We are one step closer to feeling safe again with upper-a