Coronavirus Technology Solutions
August 6, 2020
Fan Filter Units have Big Potential to Fight COVID
Lots of Applications for FCCUs
CIDRAP Providing Valuable Insights on Mask Efficiency
CIDRAP Director Responds to Mask Comments
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Fan Filter Units have Big Potential to Fight COVID
McIlvaine has been writing about fan/filter/units for cleanrooms since they were invented in the 1980s. Initially the concept of replacing a 200,000 cfm fan blowing air into a big plenum above 200 filters with the concept of 200 fan/filter units (FFUs) was rejected by the cleanroom industry but slowly the advantages became apparent. Today many millions of FFUs are used in cleanrooms. They have many energy saving and flexible features which make them ideal for some COVID mitigation applications. These include filtration and laminar flow above checkout counters and above workers on production lines.
The ENVIRCO division of Johnson Controls is a leading supplier of FFUs. The MAC 10® LEDC features the most control options and the most versatile control system available on the market today, while topping the industry in energy efficiency. The MAC 10 LEDC comes standard with the filter integral with the unit housing, while room side replaceable filters, motor blower, and now controls are available.
With the RSRC, the control card is replaceable through the top and room side. FFUs can be auto programmed with selection of the proper controller. Filters are shipped loose for easy access and replacement.
The MAC 10® LEDC FFU can help provide opportunities to earn LEED points with its many energy-saving features. Note: LEED (Leadership in Energy and Environmental Design) is the rating system of US Green Building Council by which building designs are certified.
By taking advantage of a unique combination of EC motor technology with Envirco’s proprietary baffling system and backward inclined fan, the LEDC tops the industry in energy efficiency. Its electronically commutated (EC) motor with internal microprocessor offers high performance and delivers long motor life with energy consumption rates as low as 90W @ 90 fpm. Utilizing Envirco’s experience in FFU development, the LEDC also features low sound levels of 52.3 dBA, which are a MAC 10® family benchmark.
Envirco® MAC 10® FFUs are used worldwide for a variety of critical clean air applications.
Lots of Applications for FCCUs
Meat processors have received guidance from the CDC to install partitions and to wear some type of cloth mask. Based on the latest evidence this is not good advice.
Fifty years of cleanroom design has resulted in consensus that HEPA filtration and laminar downward air flow are the ways to deal with particles smaller than 5 microns. Air pollution control experts can cite endless examples of small particles which travel around the globe. No amount of partitioning would restrict them.
Technology has been developed to deal with COVID-19 in a safe and cost effective manner by cleaning the air and directing the flow so it is not from person to person. The 6 ft voting line in Milwaukee is a good example of what not to do. A slow sequence of people moving in a straight line creates a lineal viral cloud and so people in the rear are continually walking into the cloud generated by their predecessors. In Milwaukee seven COVID case were directly tied to the voting and the entire Wisconsin caseload rose noticeably.
One takeaway is that air flow direction is very important. If a cloud moves from one meat packer under or around a partition to another worker, the partition has no positive effect and in fact may create turbulence and longer suspension. In the diagram below envision each worker in a cavity area caused by the partition where the virus keeps circulating.
There are ceiling mounted fan Filter Units (FFUs) which will provide laminar flow of HEPA filtered air. If placed properly they can provide laminar flow of clean air downward.
Meat processors are only one of the many applications where fan filter units and not partitions should be used. Checkout counters in Austria are being equipped with Ortner fan filter units. The laminar downward flow of clean air sweeps viruses away from the breathing zone. The air returns behind the individuals and is again purified in the HEPA filter.
The aisles of stores can also be supplied with laminar air flow ceiling mounted FFFUs.
Imagine Fiberglass Products Inc., allows kids to safely return to school without the discomfort of wearing a mask for most of the day. The IsoBooth Student system helps to protect eyes, nose, and mouth against exposure to droplet and aerosol viral contaminants, like COVID-19.
The diagrams below show how Air Quality Engineering’s unique four-way (360 degree) air recirculation system works. Air movement experts refer to it as the “Coanda Aerodynamic Principle” which is the most efficient way to circulate air.
· The company says it takes advantage of and works with the natural, upward movement of air vs. the old-fashioned, horizontal approach.
· Air cleaners are installed directly overhead in problem areas to isolate and capture smoke BEFORE it disperses.
· It eliminates “Dead Spots”; hence it is more efficient in overall cleaning.
· The more uniform, ceiling-to-floor air circulation saves on heating and cooling. There are NO HEAVY DRAFTS as with the “pass-thru” units.
· In many applications, one of COANDA air cleaners will do a better job than two “pass thru” units.
CIDRAP Providing Valuable Insights on Mask Efficiency
The Center for Infectious Disease Research and Policy (CIDRAP; "SID-wrap") is a global leader in addressing public health preparedness and emerging infectious disease response. Founded in 2001, CIDRAP is part of the Office of the Vice President for Research at the University of Minnesota.
CIDRAP is tracking and analyzing the rapidly evolving novel coronavirus (COVID-19) pandemic. The CIDRAP COVID-19 Resource Center provides a deep well of information for public health experts, business preparedness leaders, government officials, and the public. It published an article on masks.
On May 6 we reported on comments by Dr. Lisa Brosseau in Infection Today where she was quoted as saying, “At the end of the day, the only thing that provides personal protection for the person wearing the mask is a respirator.”
CIDRAP has received lots of comments on a paper provided by Lisa who is a national expert on respiratory protection and infectious diseases and professor (retired), University of Illinois at Chicago and Dr. Margaret Sietsema who is also an expert on respiratory protection and an assistant professor at the University of Illinois at Chicago.
In response to the comments the authors and CIDRAP have received requests in recent weeks to remove this article from the CIDRAP website. Reasons have included: (1) we don’t truly know that cloth masks (face coverings) are not effective, since the data are so limited, (2) wearing a cloth mask or face covering is better than doing nothing, (3) the article is being used by individuals and groups to support non-mask wearing where mandated and (4) there are now many modeling studies suggesting that cloth masks or face coverings could be effective at flattening the curve and preventing many cases of infection.
If the Data are Limited, How can We Say Face Coverings are Likely Not Effective?
We agree that the data supporting the effectiveness of a cloth mask or face covering are very limited. We do, however, have data from laboratory studies that indicate cloth masks or face coverings offer very low filter collection efficiency for the smaller inhalable particles we believe are largely responsible for transmission, particularly from pre- or asymptomatic individuals who are not coughing or sneezing. At the time we wrote this article, we were unable to locate any well-performed studies of cloth mask leakage when worn on the face—either inward or outward leakage. As far as we know, these data are still lacking.
The guidelines from the Centers for Disease Control and Prevention (CDC) for face coverings initially did not have any citations for studies of cloth material efficiency or fit, but some references have been added since the guidelines were first posted. We reviewed these and found that many employ very crude, non-standardized methods (Anfinrud 2020, Davies 2013, Konda 2020, Aydin 2020, Ma 2020) or are not relevant to cloth face coverings because they evaluate respirators or surgical masks (Leung 2020, Johnson 2009, Green 2012).
The CDC failed to reference the National Academies of Sciences Rapid Expert Consultation on the Effectiveness of Fabric Masks for the COVID-19 Pandemic (NAS 2020), which concludes, “The evidence from…laboratory filtration studies suggests that such fabric masks may reduce the transmission of larger respiratory droplets. There is little evidence regarding the transmission of small aerosolized particulates of the size potentially exhaled by asymptomatic or presymptomatic individuals with COVID-19.” As well, the CDC neglected to mention a well-done study of cloth material filter performance by Rengasamy et al (2014), which we reviewed in our article.
Is Wearing a Face Covering Better Than Nothing?
Wearing a cloth mask or face covering could be better than doing nothing, but we simply don’t know at this point. We have observed an evolution in the messaging around cloth masks, from an initial understanding that they should not be seen as a replacement for physical distancing to more recent messaging that suggests cloth masks are equivalent to physical distancing. And while everyone appears to understand that this messaging suggests that a cloth mask is appropriate only for source control (i.e., to protect others from infection), recent CDC and other guidance recommending their use by workers seems to imply that they offer some type of personal protection.
We know of workplaces in which employees are told they cannot wear respirators for the hazardous environments they work in, but instead need to wear a cloth mask or face covering. These are dangerous and inappropriate applications that greatly exceed the initial purpose of a cloth mask. We are concerned that many people do not understand the very limited degree of protection a cloth mask or face covering likely offers as source control for people located nearby.
Do We Support Cloth Mask Wearing Where Mandated?
Despite the current limited scientific data detailing their effectiveness, we support the wearing of face coverings by the public when mandated and when in close contact with people whose infection status they don't know. However, we also encourage everyone to continue to limit their time spent indoors near potentially infectious people and to not count on or expect a cloth mask or face covering to protect them or the people around them. The pandemic is not over and will not likely be over for some time. As states and local jurisdictions reopen, we encourage people to continue to assess and limit their risks. Cloth masks and face coverings likely do not offer the same degree of protection as physical distancing, isolation, or limiting personal contact time.
Will Face Coverings 'Flatten The Curve' and Stop the Pandemic?
We have reviewed the many modeling studies that purport to demonstrate that cloth masks or face coverings have the potential for flattening the curve or significantly decrease the number of cases. These studies fail to recognize several important facts:
· The filter performance of a cloth material does not directly translate or represent its performance on an individual, because it neglects the understanding of fit.
· Cloth masks or coverings come in a variety of shapes, sizes, and materials and are not made according to any standards.
· Transmission is not simply a function of short random interactions between individuals, but rather a function of particle concentration in the air and the time exposed to that concentration.
· A cloth mask or face covering does very little to prevent the emission or inhalation of small particles. As discussed in an earlier CIDRAP commentary and more recently by Morawska and Milton (2020) in an open letter to WHO signed by 239 scientists, inhalation of small infectious particles is not only biologically plausible, but the epidemiology supports it as an important mode of transmission for SARS-CoV-2, the virus that causes COVID-19.
In summary, though we support mask wearing by the general public, we continue to conclude that cloth masks and face coverings are likely to have limited impact on lowering COVID-19 transmission, because they have minimal ability to prevent the emission of small particles, offer limited personal protection with respect to small particle inhalation, and should not be recommended as a replacement for physical distancing or reducing time in enclosed spaces with many potentially infectious people. We are very concerned about messaging that suggests cloth masks or face coverings can replace physical distancing. We also worry that the public doesn't understand the limitations of cloth masks and face coverings when we observe how many people wear their mask under their nose or even under their mouth, remove their masks when talking to someone nearby, or fail to practice physical distancing when wearing a mask.
CIDRAP Director Responds to Mask Comments
Dr Michael Osterholm responded to the mask comments and to explain why CIDRAP will not remove the article from its website.
Dr. Osterholm is Regents Professor, McKnight Presidential Endowed Chair in Public Health, the director of the Center for Infectious Disease Research and Policy (CIDRAP), Distinguished Teaching Professor in the Division of Environmental Health Sciences, School of Public Health, a professor in the Technological Leadership Institute, College of Science and Engineering, and an adjunct professor in the Medical School, all at the University of Minnesota. From June 2018 through May 2019, he served as a Science Envoy for Health Security on behalf of the US Department of State. He is also on the Board of Regents at Luther College in Decorah, Iowa.
He is the author of the 2017 book, Deadliest Enemy: Our War Against Killer Germs, in which he not only details the most pressing infectious disease threats of our day but lays out a nine-point strategy on how to address them, with preventing a global flu pandemic at the top of the list.
In response to the comments relative to the mask article, Osterholm said “Science, when done well, can be messy, imperfect, and slower than we wish. And it's ever-evolving. Unfortunately, in the time of a pandemic, we wish this weren't the case, as we all want and need immediate answers.
Public health policy—including COVID-19 response—should always be informed by the best data available and should evolve with scientific knowledge. But it should not be based on popular opinion or even well-meaning movements within the scientific community. Good science should precede policy, not vice versa.
From the very first cases in China, CIDRAP has been compiling and disseminating science-based information and straight talk on COVID-19. In fact, our dedicated team has been providing science-based, non-partisan coverage of infectious diseases for nearly 20 years. Our only agenda is to inform the public about what the scientific community knows and does not yet know about COVID-19. We take this same approach with cloth face coverings.
At the outset, I want to make several points crystal clear:
· I support the wearing of cloth face coverings (masks) by the general public.
· Stop citing CIDRAP and me as grounds to not wear masks, whether mandated or not.
· Don't, however, use the wearing of cloth face coverings as an excuse to decrease other crucial, likely more effective, protective steps, like physical distancing
· Also, don't use poorly conducted studies to support a contention that wearing cloth face coverings will drive the pandemic into the ground. But even if they reduce infection risk somewhat, wearing them can be important.
I've received increasing criticism in recent weeks because I've offered more nuanced messaging on whether everyone should wear cloth face coverings in public to protect against COVID-19 transmission—messaging that some view as unacceptable. The criticism has included a recent commentary by Masks4All proponents Jeremy Howard and Vincent Rajkumar, MD, that mischaracterizes my position on cloth face coverings and misrepresents the science of personal protection for COVID-19.
Again, I want to make it very clear that I support the use of cloth face coverings by the general public. I wear one myself on the limited occasions I'm out in public. In areas where face coverings are mandated, I expect the public to follow the mandate and wear
"I'm working with a group of some of the country's most renowned technology leaders to develop a reusable N95 mask that could be washed hundreds of times without losing its electrostatic charge and fit…If these masks can become a reality and many, many millions of them made and distributed to the public around the world in the next few months, this could be a real game-changer. So anyone who claims I don't think masks are important, they are just plain wrong. I do. In fact, I think about it frequently as my daughter, who is a neonatologist, goes to work every day to a potential COVID situation. I think about that all the time."
In the same vein, we must not conflate the sheer number of recent studies on cloth face coverings with quality. A series of papers have been published in recent weeks addressing the effectiveness of cloth face coverings, but they collectively lack scientific rigor for a variety of reasons, including a much-touted meta-analysis that did not even include studies of cloth face coverings in the community but rather included studies largely on surgical masks and N95 respirators used in healthcare settings.
It is critical that not just more research, but high-quality research be conducted so that the scientific community can assess the effectiveness of cloth face coverings in reducing COVID-19 transmission. Transparency is sorely needed in two areas in particular to help us parse out the impact of cloth face coverings: the setting in which the studies are conducted (e.g., hospital settings vs community-based settings) and whether they assess respirators, surgical masks, or cloth face coverings.
"We know that the virus can be transmitted by what we call [aerosols—mistakenly termed 'air assaults' by WCCO]—it's the tiniest of particles. If anything comes in along the side of the mask or escapes that way, then it really minimizes both [the] protection for the individual who used the mask or the protection for others so that if I'm infected, I don't transmit to them. That's when you get into the surgical masks and to the cloth masks. And quite honestly, the data for both is lacking that they are major impediments [in either] getting infected or infecting others."
"People want to wear a mask. That's great. But I think we're going to show in the end that many more health care workers were infected by working with only surgical masks and not N95 [masks]. I realize and understand the shortage of N95 … I get that [surgical masks] are better than nothing, but I don't think that it offers anywhere near the protection that we need for this virus."
While the science on this issue remains ongoing, numerous limitations have plagued studies completed to this point, complicating any meaningful judgment as to the role that cloth face coverings can play in helping control this pandemic. Quality data assessing the effectiveness of cloth face coverings are still lacking, as noted by Roger Chou, MD, and colleagues in a recent rapid review article and follow-up letter in the Annals of Internal Medicine. My statements align with advice offered in the aforementioned UNCOVER report—which recommends emphasizing the lower protective capabilities of cloth face coverings to the public.
