Your HVAC Filter Won't Kill a Virus
Updated: Mar 31
Indoor Air Quality in the Time of COVID-19
Maintaining a high level of indoor air quality (IAQ) is an important challenge even in the best of times. Allow your mind to wander back to easier days, back when there was no global pandemic, and we simply battled crippling seasonal allergies. When sick memes infected the office.
We’ve always had to contend with dust, pollen, fungi, bacteria, smoke, possible chemical emissions from the paint on the walls or even office furniture, and all sorts of other misfits waltzing along with the air of our indoor spaces. And yes, viruses. Properly eliminating a high percentage of any of these pollutants has never been easy. Eliminating all of them is impossible.
The coronavirus is spread by person-to-person contact, as well as coming into contact with contaminated surfaces. The best option for minimizing the spread is to avoid...humans and practice good hygiene.
ASHRAE recently provided a great deal of guidance and helpful resources on how to consider COVID-19 when building or maintaining HVAC systems. You’ll find links to ventilation standards for residential buildings, healthcare facilities, and aircraft, among other IAQ standards. Additionally, a link to ANSI/ASHRAE Standard 185.2-2014, Method of Testing Ultraviolet Lamps for Use in HVAC&R Units or Air Ducts to Inactivate Microorganisms on Irradiated Surfaces.
The use of UV in battling microorganisms isn’t new, however, the implementation in HVAC systems could become more common. Viruses are tiny, too small to be captured by commercially available HEPA (high-efficiency particulate air) filters.
Assistant Professor of microbiology and member of Georgetown’s Center for Global Health Science and Safety recently told Buzzfeed News, “Your typical HEPA filter is not going to be able to remove coronavirus from the air”.
Studies on the effectiveness of UV regarding microorganisms have proven positive, but it would seem there is plenty more research that could be done. According to the ASHRA Studies of Airstream Disinfection Effectiveness:
Laboratory studies (e.g., RTI 2005; VanOsdell and Foarde 2002) conclusively demonstrate the ability of commercially available equipment to achieve a high level of disinfection of moving airstreams. These studies have generally involved tests with surrogates rather than actual infectious disease agents, but it can be assumed that an infectious agent with a k-value similar to an experimental surrogate will be similarly inactivated….Many UV airstream disinfection systems have been installed in hospital environments to help reduce pathogens by complementing conventional dilution/filtration systems.
At PermitZIP, we are always focused on finding solutions. We are committed to finding ways our design team can be helpful in this current crisis, and to the industry as a whole. This business was created to bring “A-team” service to smaller MEP consulting projects, and our focus on every detail allows us to make, and keep (well...except that one time, which we’ll talk about in an upcoming blog) our Two Week Promise. We offer Instant Quotes and free site surveys, so please contact us if you’d like to learn more about our process. Let us know if you are considering retrofitting or building an HVAC system with an emphasis on virus reduction.
We also work with and refer customers to our network of trusted contractors, like W.G. Speaks in Midlothian, who has a lot to say on the matter of how HVAC systems can improve IAQ.
As businesses, facilities, and even homeowners consider new ways to include more stringent virus reduction on our IAQ plans, perhaps it is best to refer to some strategies offered by ASHRAE:
ASHRAE recommends the following strategies of interest to address disease transmission: dilution ventilation, laminar and other in-room flow regimes, differential room pressurization, personalized ventilation, source capture ventilation, filtration (central or unitary), and UVGI (upper room, in-room, and in the airstream).
Owners, operators, and engineers are encouraged to collaborate with infection prevention specialists knowledgeable about the transmission of infection in the community and the workplace and about strategies for prevention and risk mitigation