Fit Test the Planet

All you need is logarithms.

[Fit Test the Planet @FitTestMyPlanet]

Prof Jeffrey Siegel has been looking at in-situ HVAC systems for years. Now that so many engineers & hobbyists have their own CPC’s like 8020A’s & can read counts into a terminal, you can negotiate down the price with the HVAC installation people until they fix any half-ass work.

[Conor Browne @brownecfm]

My strong suspicion is that we will read much more research over the coming years that begins with, 'a common virus once thought harmless to humans'.

[Fit Test the Planet @FitTestMyPlanet]

Attempts at alternatives to jaw spacers ordered from most likely to work to least likely to work.

[Fit Test the Planet @FitTestMyPlanet]

You know what time it is

[Fit Test the Planet @FitTestMyPlanet]

Outline for a UI prioritizing a logarithmic readout

[Fit Test the Planet @FitTestMyPlanet]

@jubbleso @Ninawildflower @FitTests4All @_CatintheHat @FaceMaskStore Trident RTCFFP2S, Trident RTCFFP3US, and Trident RTCFFP3USB are good candidates. All have slightly different baseline tensions, so if they pass a QLFT or QNFT in one model, you’ll want to redo the test in the other model before switching. (Black is out of stock at the moment).

[Fit Test the Planet @FitTestMyPlanet]

@Rose_Mary_X @masknerd Still 75 sprays total.

[Fit Test the Planet @FitTestMyPlanet]

@CoronaZeroCH @GrumpyParticle Looks about right! The second graph in the thread is great. At some point concentration gets so high that the chance of multiple particles being in the path of the laser beam starts to add the error. 1e4 to 2e4 works for everything. 1e3 is enough for sifting through disposables.

[Fit Test the Planet @FitTestMyPlanet]

The tiny filter is a great demonstration piece of how important CADR is compared to single pass filtration efficiency. Even if it was H13, the protection wouldn’t benefit.

It’s definitely not the best use of effort/money…at least for the use cases these are advertised for and for the accessories they come with. The core mechanism could in principle be alright for positively displacing a *nearly* closed volume of about a cubic meter. Like perhaps a glass terrarium for small animals…but in that case you’d need an engineer to determine a reasonable outlet aperture. The protection factor in that scenario can get to 50-100 fold. But if the device is just recirculating then the filter is just competing to catch the viral particles before the person it’s near to…but it doesn’t the CADR to do that well so the effect is negligible.

[Fit Test the Planet @FitTestMyPlanet]

It’s definitely not H13, but the worst part is how ineffective small devices like these are at doing drawdown even in small volumes.

The actual single pass efficiency measured through a reservoir is slightly higher (~2 logs). 0 inches already has some entrainment on this device!

[Gerard Hughes ( @ghhughes.bsky.social ) @ghhughes]

At 0 inches the "fit factor" was 7.1, which translates to a sub-micron filtration efficiency of 86%, which is lower than I would expect for a claimed "True Hepa Filter" with "99.97%" filtration.

[Fit Test the Planet @FitTestMyPlanet]

@ghhughes Yeah that’s pretty bad.

[Fit Test the Planet @FitTestMyPlanet]

@lovemoz1 @Francien_NL @chngin_the_wrld All these have KN95. Picture has changed even more sibd

[Fit Test the Planet @FitTestMyPlanet]

KN95 update - expanding options at the high end

https://t.co/KR7Na07Si5

[Fit Test the Planet @FitTestMyPlanet]

@lovemoz1 @Francien_NL @chngin_the_wrld Masks with KN95 / N95 / FFP / KMOEL2017 etc approvals are not monolithic. Some of the best new masks of 2023 and 2024 have had KN95 as their only approval.

[Fit Test the Planet @FitTestMyPlanet]

@Jackk1372742 That adhesive FFP2 is in the queue but it could be a while before the excel closes in on a span. Sometimes really adaptable and resilient masks show up in just months, the longest time period between finding a mask and sufficiently stressing it has been about a year (3/n)

[Fit Test the Planet @FitTestMyPlanet]

@Jackk1372742 The issue isn’t just “is it MRI-safe” and “which one protects you well”, it’s also “which one will the radiology tech allow”. I am fairly sure that my 8955K Korea 1st Class is MRI safe, however in 2024 it doesn’t show up on google as MRI-safe should the question come up (2/n)

[Fit Test the Planet @FitTestMyPlanet]

Readers added context

[Chris Hayes @chrislhayes]

we need an indoor clean air act

[Fit Test the Planet @FitTestMyPlanet]

One of the most expensive disposables we send out - the Shigematsu Gardening Mask. I don’t know any other international links for it right now. Not a best pick as a daily mask (outside of Japan at least) bc of cost. https://t.co/UYTvVtehmR

[Fit Test the Planet @FitTestMyPlanet]

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.
https://t.co/Cmpmn79iBD

[Fit Test the Planet @FitTestMyPlanet]

Someone just found a link to Zekler1502smalls that ships boxes of 20 worldwide. (The Australian site only has 3 or 10 packs and the Finnish site only ships to continental Europe). The ML have the same issues as Drager ML’s so get small unless you do QNFT.
https://t.co/Ct2SDuUXKH

[Fit Test the Planet @FitTestMyPlanet]

Resilience Test Friday - We’re months behind on shipping testing gear out but it has to be mentioned: model 4803 came out of nowhere as a possibly general-purpose jaw movement resilient design.