Lmst

I made a #CorsiRosenthalBox using 4 Arctic P14 fans. I can't feel much of a draw when placing my palm against the filter. Anyone know if this is normal?

You don't get many box fans here in the UK!

I built a Corsi-Rosenthal Box! Here are my tips on building a Corsi-Rosenthal Box air cleaner for an airborne pandemic like COVID-19.

https://www.conferencesthatwork.com/index.php/resources-2/2022/05/tips-on-building-a-corsi-rosenthal-box-for-an-airborne-pandemic

#HowToBuild #CorsiRosenthalBox #tips #IAQ #AirPurifier #AirFilter #DIY

A photograph of Adrian Segar's office, showing a set of parts needed to make a Corsi-Rosenthal box.

Nach der in den USA in Schulen verbreiteten #CorsiRosenthalBox gibt es nun ein interessantes neues Konzept für einen leistungsfähigeren und wesentlich leiseren DIY-#Luftfilter: die #DeisBox
https://healthydebate.ca/2025/04/topic/simple-metal-box-covid/

Breathe easier with a DIY air purifier that rivals costly HEPA systems. Discover how to build your own Corsi-Rosenthal Box for cleaner indoor air. #DIYAirPurifier #IndoorAirQuality #CorsiRosenthalBox

https://geekoo.news/diy-air-filter-rivals-costly-hepa-systems/

Last night I went to an event at the venue where my local Queer Club takes place. I took CO2 readings with my #Aranet, did some estimates of the room volume, and measured the flow rate of the filter box they have there.

In terms of raw CO2 numbers (which ignore air filtration) and Air Changes Per Hour (which ignore room occupancy) the numbers were pretty dismal.

But I got enough data to try modelling the room using co2room, a Python script I wrote.

I worked out the natural ventilation rate of the building by tweaking until the resultant curve fit the readings from the Aranet.

At 40 people last night, the "effective CO2 rate" (i.e. the CO2 readings you'd get if you were ventilating rather than filtering) topped out around 1000ppm, which is above my risk threshold.

However, at my Queer Club event which has only about 20 people, even though it runs for longer it tops out at about 500ppm.

#CorsiRosenthalBox #CovidIsNotOver #WearAMask

A graph showing CO2 readings against elapsed minutes, assuming you've suddenly dropped 40 people into a room. The CO2 that you'd measure on a meter goes up in a curve (flattened by natural ventilation) while a lower curve shows the equivalent risk considering the air filter box. The orange curve almost reaches 1000ppm.

A graph showing CO2 readings against elapsed minutes, assuming you've suddenly dropped 20 people into a room. The CO2 that you'd measure on a meter goes up in a curve (flattened by natural ventilation) while a lower curve shows the equivalent risk considering the air filter box. The orange curve reaches about 500ppm.

Here's the 20" #CorsiRosenthalBox I'm working on. Fans in rectangular housings basically don't exist in the UK, so I made a cardboard shim out of the box for this circular one.

This build was a proof of concept (hence the green masking tape rather than duct tape, and the plastic sheeting still on the #MERV13 filter boards). I was testing whether the shim and the boards would support the weight of the fan. Despite being a mock up it's surprisingly rigid!

Next stage involves building it properly (including sealing those gaps at the corners; the 20" fan is actually more like 21.5" across and the boards are 19.5"), then using my anemometer to measure the flow rate of the finished box, so I can work out what size room it can filter. I'm intending this one for a local community centre where a Queer Club meets, to make their meetings safer.

#CovidIsNotOver #CleanAir #CorsiRosenthal

A partially constructed Corsi-Rosenthal Box. This is a cube, around 20 inches per side. The bottom is just cardboard. The top is a round black plastic fan, mounted in a hole in the middle of another piece of cardboard, and held there with black duct tape. The four sides are filter boards - cardboard frames containing cloth like filter material. The boards are attached to the top and bottom with green masking tape. There are gaps at the corners because the boards are smaller than the fan's diameter.

Boo, the #MERV13Filters for my #CorsiRosenthalBox arrived today just before I go away for a week so I don't get to play with them.

Double boo - the 20" filters are a bit smaller than 20", and the 20" fan is a bit bigger, so I'm going to need a bunch of cardboard shims in the build to make everything fit nicely. And that's kind of interesting but also future me's problem / fun.

Still, when it's done I'll have two boxes that can deliver 6ACPH to a decent sized room!

#CovidIsNotOver #CleanAir

A stack of white, square MERV13 filters (basically a 20" x 20" x 1" card box with open sides, containing cloth like filter material).

It lies in top of a black 20" circular fan, covering about half of it.

Just made myself a Corsi-Rosenthal box to take to my office on Monday because people keep coming in without wearing masks.

#CorsiRosenthalBox #AirFilter

A small white fan with 10-inch air filters duct-taped to it to form an air filtering cube.

Okay last one, I promise.... I'm just mesmerized by these lol 🪩✨ #djcrbox #chemicalbrothers #corsirosenthalbox

Analysis of these kinds of systems (from the "Rosenthal" of Corsi Rosenthal). These filters have been exceptionally useful both for wildfires (removing toxic smoke and particulates after the recent LA wildfires), as well as plague-of-the-day (COVID-19, influenza, RSV, threat of bird flu now here...). Also just generally good to keep the air pollution in your house to a minimum!

https://www.texairfilters.com/comparing-the-performance-of-corsi-rosenthal-boxes-made-with-box-fans-and-pc-fans/

#corsirosenthalbox #airquality #aqi #disasterpreparedness #pandemic #wildfires #smoke

I made another one... 🪩

#corsirosenthalbox #djcrbox #hobbycraft #cleantheair

An Corsi-Rosenthal box illuminated with a red light from within

#CorsiRosenthalBox #CRBox #diy #cleanair

Grainy screenshot of a survey: "How likely are you to recommend this air purifier to a friend or colleague? Answer: 1, not at all likely. Please explain why you gave this score: I need you to understand that people don't have conversations where they randomly recommended air purifiers to one another." Corsi Rosenthal box users: bombastic side eye. (Depicted with monkey puppet side eye meme.)

@Gdac @CovidSafeScouts It's a thing of beauty! #corsirosenthalbox #CovidIsNotOver

Covid-Safe Scout Proficiency Badge No.3
DIY a Corsi-Rosenthal Box
This recipient understands how to improve ventilation with air purifiers and has constructed at least one CR box using MERV-13 filters and a box fan.

Wanna earn this badge?
Use these links to learn how to build your own air purifier using fans and filters
🔗 Clean Air Crew - DIY box fan filters – Corsi-Rosenthal box: https://cleanaircrew.org/box-fan-filters/
🔗 Dr. Richard L. Corsi - How to Build a Corsi-Rosenthal Box: https://www.youtube.com/watch?v=hIuH-2naozI
🔗 It’s Airborne - Building a PC Fan Corsi-Rosenthal Box: https://itsairborne.com/building-a-pc-fan-corsi-rosenthal-box-68e7cd1ca570
🔗 Airbon - UK DIY Air Purifiers: https://www.airbon.co.uk/post/diy-air-purifiers
• Find more useful resources about air cleaning: https://www.covidsafescouts.com/research.html#filtration

Already a seasoned Precautionista?
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• Share this post and/or your badge on your favourite socials
• Reply with #CovidSafeScouts to share your CR Box mods
• Collect all the Covid-Safe Scout badges: https://covidsafescouts.com/badges.html

#CRbox #CorsiRosenthalBox #CleanAir #CleanTheAir #CovidSafeScouts #CovidIsNotOver #CovidIsntOver #CovidIsAirborne

circle badge with Corsi-Rosenthal box comprised of square HEPA filters on the sides and a square box fan on the top

Todo for this week: build another HEPA (Corsi Rosenthal) fan system using PC fans. Even though the throughput is about 1/3 less than a box fan, the sound levels enable this system to run 24/7 if needed without complaints from family, which is a HUGE plus. #CorsiRosenthalBox #AQI #health

This weekend I've bought parts to make a couple of 20"/50cm #CorsiRosenthalBox and an anenometer to measure the resultant airflow (so I can calculate the max size of room to install them in). The parts for each box will cost me about £60.

I'm hoping to be able to lend them to #queer events in #Manchester to help protect my community from the ongoing pandemic.

It'll take a while for the MERV 13 filters to arrive, then it's time to duct-tape everything together!

#CovidIsNotOver

Running the ultra-quiet PC-fan Corsi Rosenthal in the house all day (at 1/4 speed), AQI in here is now 2 (0.5 PM2.5). Can't even hear it running at all. 40AQI outdoors right now. Fabulous. #CorsiRosenthalBox

Rest of the bits assembled. Absolutely quiet!! #CorsiRosenthalBox

12V 1.2A wall wart with added Power Pole connectors

Bottom of panel showing power and control knob

Fan mounted on existing Corsi Rosenthal cube

It's alive, it's alive! #frankenfan #CorsiRosenthalBox

Although I suspect supplies will be hard to find, here's instructions on building a HEPA purifier (Corsi Rosenthal Box). A good chunk of Ventura County is unhealthy air tonight, and it would be useful to have one or two of these running to protect your lungs. #airquality #AQI #CorsiRosenthalBox

https://engineering.ucdavis.edu/news/science-action-how-build-corsi-rosenthal-box

#CorsiRosenthalBox

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