Could a Janky, Jury-Rigged Air Purifier Help Fight Covid-19?

Started by Ever (Zombiepreparation), September 14, 2021, 04:29:58 PM

Previous topic - Next topic

0 Members and 2 Guests are viewing this topic.

Ever (Zombiepreparation)

Could a Janky, Jury-Rigged Air Purifier Help Fight Covid-19?
Indoor-air experts think: Sure, maybe. Why the hell not? We convinced the CEO of an air filter company to give it a try.

Wired Magazine entire article here

"THE IDEA SEEMS pretty simple, once someone explains it. The virus that causes the pandemic disease Covid-19 passes from human to human on tiny droplets of spittle, through the air. Masks block some of them. But what if—and I am literally spitballing here—you could clean those particles from the air itself?"

"Researchers who study aerosols have begun to think this ventilation approach is a good idea.

"A big, complicated central air system filled with filters and maybe even germ-busting ultraviolet light, like what a hospital or skyscraper might have, would be great. A $500 air purifier could make a real difference in pulling infectious bits out of a room before they can infect a person.

"But it's possible, some of them speculate, that even a store-bought filter stuck onto a $20 box fan might do some good too. It's cheap, and while it wouldn't cut the risk of infection to zero, it would still pull virus-laden particles out of the air."

"It hadn't occurred to me until two days ago, until someone pointed it out," says José-Luis Jiménez, an aerosol scientist at the University of Colorado, Boulder, "but I think it's a brilliant idea."

- Environmental engineer Richard Corsi—dean of the Maseeh College of Engineering and Computer Science at Portland State University and an indoor air quality expert took on the challenge.

"Masks are a good way to keep one's own self from being a filthy particle-emitter. Nobody wants to be the main character in a super-spreading event, right? But cleaning particles out of the air altogether has seemed like the provenance of building-wide air handling and climate control systems.

"A hospital HVAC system might cycle all the air in the building a dozen times a day, stale out and fresh in.

"But what about the rec room of a care home for the elderly, or a public school classroom? Or 50 public school classrooms? Or your house?

"A little bit of peer-reviewed science says a homebuilt kludge might work.

"One study, from Singapore and looking not at aerosolized virus but the soot and smoke of Indonesian wildfires, found that a simple filter and fan mounted in a window to pull air inside reduced particulate matter between 1 to 10 microns by around 75 percent.

"That's suggestive. The particles in the study were from smoke and soot, but they were well within the size range of the smaller, virus-bearing particles from respiration, which is what counts here."

"Top-line room air purifiers cost several hundred dollars. But a cheap DIY purifier may also cut down Covid-19 risk. The Singapore researchers used a MERV-13 filter ("minimum efficiency reporting value," duh), because perfection wasn't necessarily the goal. Reduction is. As Penn State architectural engineer William Bahnfleth has shown, while HEPA filters ring the bell at the top of the MERV scale, an idealized MERV-13 filter picks up nearly half of 0.1-micron-diameter particles, and pretty much everything 1 micron and above. That's the right size to get the particles carrying the virus too."

"If you don't have cross-ventilation, you can just set the box-fan/filter in the middle of the room. "This type of setup is especially useful for situations in which, basically, you don't have access to outdoor air. "

Box fan with 4 inch MERV 13 filter:

So that's me: (Only I used white duck tape so seal it to the fan.) I can not bring outside air in during the humidity months.

What my tiny apartment experiences in the summer high humidity months; AC must be on, but opening balcony door a bit brings in HIGH humidity, that feeds into the single circuit one apartment AC unit, feeds into the intake, that fills the space above the ceiling tiles with high humidity air, that creates a pietri dish environment for rampant mold growth, that is then sucked into the cooling blower, and blown into the apartment.


No joy for cross ventilation during those months.

This is the one I built:

Ever (Zombiepreparation)

And then came 'A Variation on the "Box Fan with MERV 13 Filter" Air Cleaner'
Article and details here

The "Box Fan with a MERV 13 Filter" air cleaner is an easy-to-assemble, inexpensive and effective way to improve indoor air quality and to reduce exposure to Covid-19. The concept is really simple – attach an effective air filter to a box fan and clean the air.

"But what would happen if we created a "box" using multiple pleated filters? Good question. Let's find out.

"To test this we used 5 filters – two 16X20X2 and three 20X20X2."

The first "Corsi Box" built with 5 MERV 13 filters and a box fan.

Ever (Zombiepreparation)

Which has recently been given a tweak to improve it.

"How to Improve the Efficiency of the "Box Fan and MERV 13 Filter" Air Cleaner"

Article and details here

"A few weeks ago I was measuring the airflow of a "Corsi Box" and noticed that it was significantly reduced in the "corners" of the box fan. In fact, in the areas closest to the corners, the air was actually going in the opposite direction. It was moving toward the fan.

"I received an email from Sam Bullard of Charlotte, North Carolina.

"Sam is not an HVAC practitioner. He is a homeowner who tries to "figure things out." He was able to solve the HVAC system sizing and ducting problems in his house so that a contractor could do the work properly. In the process, he read Manual J, bought the instruments and did the measurements necessary to prove his points.

"One of those instruments was an anemometer. This device is like a small windmill that tells airflow direction and velocity.

"He detected the same reverse direction air flow in the corners of the box fan that I had seen.

"The "net" airflow – plus from the fan minus negative on the corners – is significantly positive. However, this is not the best situation and, at least for the "Corsi Box," it can result in some air not going through the filters.

"How do we solve this?"

"The automotive industry has dealt with it for many years. Fans are used on cars and trucks to cool the radiator. In order to direct the air flow from the fan, they use what is known as a "fan shroud." This closes the gaps at the corners and stops the turbulence that reduces the efficiency of the fan. "

So that's what they did. With cardboard.

"Is the "fan shroud" tweak of the Box Fan and MERV 13 Filter air cleaner absolutely necessary? No, but it does improve the performance. It just takes a few minutes to do. I am adding it as an additional step in both of the articles on building this air cleaner. It works!"

  "On one of my fans, I just taped the front of the fan on the corners and it seemed to work just fine."

So I taped my own home made one. Less work.


This is incredibly good info to share.

Are you using this in addition to the air purifiers you ordered?
"Seriously the most dangerous thing you are likely to do is to put salt on a Big Mac right before you eat it and to climb into your car."

Ever (Zombiepreparation)

Yep. Not always working their little hearts out. And 'my' smaller version of the box-fan fits nicely.

Everything's so light weight and moveable.  I can move them where I want them I can turn them as high or as low as I want them and they do different things around the apartment.

Portable & light enough to take some of them with to the (now) nine day Radisson bug-out.

No windows to open for cross ventilation, the only new oxygen comes around & under the hallway door.

The box-fan to mitigate possible delta aerosol in hallway, two desktops to mitigate the mold.

Yep. 😊 I like em.

And were, the gods forbid, another pandemic to come along or this one gets worse I will build the actual Corsi fan with all those 2" HEPA filters. Set it closer to my hallway door to, again, work on cleaning any contaminants getting in from the hallway.

SMF spam blocked by CleanTalk