Fit Test the Planet

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.

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'.

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

Outline for a UI prioritizing a logarithmic readout

You know what time it is

@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).

Can someone pls recommend a good all round mask for kids (UK,aged 11&13), kinda equivalent to 3M aura for adults? I know ppl prob already have but I wasn’t paying attention and can’t find the posts now! @Ninawildflower @FitTestMyPlanet @FitTests4All @_CatintheHat @FaceMaskStore

@Rose_Mary_X @masknerd Still 75 sprays total.

😷 FIT TEST Q - PLEASE RT 😷 Sensitivity test only accounts for min 10 sprays b4 taste detection. What if u can taste after e.g. 3? Can/shld u lower the amnt of sprays for the actual fit test? Thanks 🙏 #COVIDisAirborne #FFP3 @masknerd @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.

@GrumpyParticle is referring to a "mask testing machine", a so called Portacount. The higher the ambient particle concentrations, the lower the margin of error according to him. @FitTestMyPlanet what do you think?

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.

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!

@ghhughes Yeah that’s pretty bad.

@FitTestMyPlanet Yet they market it as if it can project a zone of clean air at a distance - they imply it in all the photos, but are careful to omit exact claims in the marketing text. All the photos show it specifically being directional.

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

@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.

🦠🥼 ⁦@DanielGriffinMD⁩ discussed this open access paper last night (Friday) on his clinical update. I’m going to post his update tomorrow w/important time markers. Next Friday night he’s discussing a CELL paper on neurological changes after 1/ thelancet.com/journals/eclin…

@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)

@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)

Readers added context

we need an indoor clean air act

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. ibspot.com/products/shige…

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. thefacemaskstore.co.uk/zekler-1502-ff…

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…

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.