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Fit Test the Planet Profile picture
Fit Test the Planet
@FitTestMyPlanet
All you need is logarithms.
Jun 22 • 4 tweets • 2 min read
Ok. Back to testing stuff. Claimed laminar flow device #3 - These two flow lines in the middle are not smoke pencils. I’m not sure how they’re forming and I’m slightly afraid to put my camera too close as I’ve already lost a camera and a phone to lasers like this. VR goggles w passthrough > laser goggles.
Jun 9 • 8 tweets • 3 min read
Disclaimer: These are *not* the filters that layer the most protection per dollar and clear out rooms - only high CADR filters can do that. The tests are called “drawdown tests” check out @DavidElfstrom

This laminar stuff is to see what’s possible - it’s not safety equipment. @DavidElfstrom This is a very stylish device that has a protection factor lower than a baggy blue and costs over $100. The plot is from earlier tests using glasses/Tygon clip. @ghhughes

Image
Jan 19 • 6 tweets • 2 min read
This mask is on the *very* short list of good, MRI safe respirators. Regarding MRI, contrary to popular belief, Envo Pro and Flo Mask Pro are not metal-free (any metal can cause heat injuries and imaging artifacts in MRI). They’re also not even ferrometal free - so they can become projectiles in an MRI machine. Forget mods…just…no. Image
Dec 30, 2023 • 11 tweets • 4 min read
#CPCcrashcrew 8020Agang general Image News:
As always, huge contributions in the public interest by regular volunteers.

New people trying condensing particle counters! @DavidElfstrom using an 8020A for drawdown testing of filters and CR boxes.

@fiveisgreen @ingomar_gutmann @03perf @qntlycurious @findmeabluebird Image
Dec 13, 2023 • 4 tweets • 2 min read
It has been over a year and a half since the UK Health and Safety Executive broke the painful news that “Earloops are Unreliable - Even with S-Hooks”.



Although new earloops with stronger nosewires have come out since, humans haven’t grown stronger ears. hse.gov.uk/safetybulletin…
Image For those that are new here, the bottom of the thick line is what you want to pay attention to. Over 30hmff is a good start (or a knockdown of 1.5 on a log10 scale). If you haven’t found a good mask for QNFT, ignore the height, start with masks that have decent Lower Quartiles.
Oct 13, 2023 • 17 tweets • 6 min read
Fit Test Friday - Core 300 single pass filtration efficiency


Image A bit of a different test today. Units 04 and 08 are logging counts/cm3 every two seconds. Unit 05 is doing its own exposure reduction calculation in a different mode. It’s also an excuse to figure out how good unit 05 is compared to the others. Image
Jul 30, 2023 • 7 tweets • 3 min read
4 hours of testing QT3 filter today.
The good news:
Filters in-situ
99.1% removal at speed 1
98.9% removal at speed 3

However… Image Some people have been using them as blow-by-paprs at a distance. Here are the early results: Image
Jun 26, 2023 • 30 tweets • 7 min read
Mask overviews aggregate thread. Each number is a harmonic mean of 12 exercises using the (non-computer vision assisted) jaw motion protocol.
1/n
docs.google.com/spreadsheets/u…
Image 2/n Image
Jun 15, 2023 • 5 tweets • 2 min read
For engineers just tuning in to the #8020Agang scene now, a thread.
1/n Back in 2022, @ghhughes started posting an interesting kind of mask test on his youtube channel . Broadly surveying common public health masks using condensing particle counting equipment originally used mostly for firefighting and military masks. 2/n Image
Jun 1, 2023 • 6 tweets • 3 min read
If you’re an engineer and are looking for a major time commitment of a hobby, you can probably get a used 8020A up and running in half a year using just eBay. 1/n Image You could set up a pair of machines and do some statistical analysis to make sure you’re confident in the results. If someone from #8020Agang is in your area, it’s a mad scientist meetup! 2/n Image
May 20, 2023 • 7 tweets • 2 min read
If you’re using a black respirator and it’s not one of these three, any one of these three is an upgrade. That is all. Image Image
May 19, 2023 • 5 tweets • 2 min read
Things you can fit test (or at least particle count) that aren’t masks, paprs, or hepas:
Your own car’s cabin filter. Mine hasn’t been replaced in 5 years. Outside air was 3K particles / cm3 at the time.
Curious to see what happens when I finally change it. ImageImage You can measure the particle count in a hospital room (~5K here). Image
May 17, 2023 • 5 tweets • 2 min read
Recommended black masks list:
1.iMaskUA iMask-3 (out of stock)
2.iMaskUA iMask-2
3.“Stapled Head Straps Wellbefore, Premium 3D PRO KN95 Mask (KF94 Style)” Image Image
May 2, 2023 • 4 tweets • 2 min read
I’m not sure people understand how unregulated this space is. The mask on the bottom is a vertical bifold with bread twist tie nosewire and happens to be a legit N95. Its typical protection(hmff) is 30 times worse than the *worst series of another respirator. This is still legal. Image That wasn’t even a cherry-picked example. There’s no bottom to this. I can’t think of another example of types of products where you get this much variation. Image
May 2, 2023 • 4 tweets • 2 min read
*facepalm* ImageImage A ladder with a broken rung is worse than no ladder at all. It also reflects poorly on ladders in general.

Apr 30, 2023 • 4 tweets • 2 min read
ChatGPT has a long way to go before it can pack this much wrongness into one tweet. Image Unpacking the multiple layers of wrong assumptions:
Layer 1:
An implicit misunderstanding of how electret filters work - thinking that they’re like sieves rather than the overlapped sticky spiderwebs that they actually are. Image
Apr 16, 2023 • 13 tweets • 6 min read
I guess this has to be a thing.
*Ahem*
Purchase link thread for Non-European buyers of 1863+’s and other Aura FFP3s:

Source #1. Car Zone, eBay (The first place I found them.) Great for samples. Yes they’re real. Unpredictable shipping.
ebay.com/itm/2553664248… 1863+, small quantities
Source #2. Thefacemaskstore uk (Thank you @JennJVN)
These will deliver to USA in 1 week, but high shipping cost.

thefacemaskstore.co.uk/3m-1863-ffp3-u…
Jan 18, 2023 • 4 tweets • 3 min read
@amandalhu @ibrake4ants I tested a replica of Ed’s dental papr concept using a quantitative fit testing machine, and it reduces exposure by at least two orders of magnitude better than the portable uv. Ie if you use the dental papr you don’t need readimask or uv at the dentist. @amandalhu @ibrake4ants Results were pretty good. It helps if you use an O-ring in addition. Image
Jan 6, 2023 • 12 tweets • 4 min read
Black with no logo is the only acceptable mask for much of the public, and yet @3M, Drager, etc can’t get their shit together and just make a 200ff mask that bypasses outdated industry habits. Every day they don’t make a textless black mask, more people are getting long covid. If more of the public had fit test machines they’d be pissed