Are there means to deactivate COVID through one’s HVAC system?
Childress and Cunningham Architects works hard to stay at the forefront of technologies that improve our client’s lives. Whether it be newly available materials that improve longevity or sustainability, or mechanical and electrical systems that improve comfort or efficiency, we research emerging trends to better serve our clients.
Aside from the usual day-to-day adjustments we’ve all made to adapt to the realities of the current pandemic, Childress and Cunningham has taken the step of testing out a new Needlepoint Bi-polar Ionization (NBPI) System in our office. This retrofit system promises to treat the air stream to remove pathogens, and is easily installed in an existing HVAC system, making it a readily-achievable option for our clients as well.
How Does NBPI Work?
From a functional standpoint, the Needlepoint Bi-polar Ionization (NBPI) System that we purchased consists of a small maintenance-free unit (blue box in the photo below) powered by the electronic air cleaner terminals in our forced-air HVAC system. It sits downstream from the main filter and just before the inlet to the system fan (at the end opposite the motor), allowing the brush assembly to ionize particles in the air before it enters the fan and then the cooling coil. This system runs continuously whenever the system fan is on.
The theory is that the high concentration of positively and negatively charged ions created in the air stream will attract foreign particles to trade electrons with, clumping particulates together into larger bodies that existing filters can remove from the air. For microbial pathogens, ions are thought to disrupt cell functions and a virus’s “corona” coating, in a manner that may be similar to the antimicrobial effects of copper. This article by Business Insider gives a more thorough overview of the technology, which has been around for some time but only sparingly used in certain sensitive situations. The system installed in our office is new in that it is being marketed much more broadly, as people have gained an awareness of the role that indoor air quality can play.
Ion concentrations in the natural environment can vary by location and seasonally, and (except for city centers) in general tend to be higher than what we get inside of air-conditioned spaces. There have been many studies on the effects of negative air ions on human health and mood, and there is already a market for ionizers sold as supplementary HVAC equipment to make up the seeming lack. By adding ions to the air, NBPI is presenting our bodies with ion levels to which we are already naturally adapted.
Positives and Negatives of Ionization
Bi-Polar Ionization in general gained a bad reputation early on because it tended to produce ozone (O3) as a byproduct, and concentrations of O3 are unhealthy. This was due to the technology used, called corona discharge. As explained in this March 2019 article from HVACinsider.com, there is an alternative called Needlepoint BPI, and it does not produce ozone. By specifying that the system meet UL 867 and UL 2998 certifications, these systems will not generate ozone concentrations.
According to Best Engineering PLC, there is a subtle danger to NBPI, in that cleaning the air of pathogens does not reduce CO2 concentrations, so the HVAC design must still have the capacity for sufficient air changes per hour. Prior to the CoVid-19 pandemic, a primary reason to employ an ionization system was to reduce the design air changes per hour. However, as a retrofit package, presumably the HVAC system is already meeting ventilation requirements and thus this concern is mitigated.
With the system now running, some of us can detect a faintly metallic smell to the air, like after a thunderstorm. This is not objectionable and one quickly becomes accustomed to it. Assuming it is working as advertised, maintenance may need to be increased in terms of replacing filters with greater frequency, to avoid placing additional strain on the blower.
What if it doesn’t work against this specific virus? There have been tests to show broad efficacy, and the system manufacturers rely on these in their claims. However, more standardized tests with Covid-19 in real-world settings may be needed. Some of the studies cited substitute a common cold virus to obtain their measurements, and they occur within perfect lab conditions with sealed environments. With this in mind, our office is continuing with proactive measures such as social distancing and working from home when possible, taking one’s temperature upon arrival, and wearing a mask when interacting with others.
At the very least, this method of air purification represents a low initial cost and low maintenance method of improving air quality as it has already been utilized to remove allergens, dust, etc, from the air stream. We will enjoy the benefits of a more healthy air supply regardless; protection against airborne Covid-19 is icing on the cake. Global Plasma Solutions, the maker of the system we have installed, reports that they have achieved a 99.4% inactivation of SARS-CoV-2 (CoVid-19) within 30 minutes exposure, in a joint study executed with Aviation Clean Air.
“In this laboratory study, Aviation Clean Air designed a test to mimic ionization conditions like that of a commercial aircraft’s fuselage. Based on viral titrations, it was determined that at 10 minutes, 84.2% of the virus was inactivated. At 15 minutes, 92.6% of the virus was inactivated, and at 30 minutes, 99.4% of the virus was inactivated.”
We would be glad to discuss this system with you, if you are considering ways to improve your building in light of the current pandemic. There are other building design technologies, such as antimicrobial copper and UVGI, that could be considered as well; please see our prior article for an overview.