All you need is logarithms.
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Joined November 2022
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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.
Fit Test the Planet retweeted
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'.
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!
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.
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Fit Test the Planet retweeted
we need an indoor clean air act
Air purifiers in Finnish daycare reduced children's illnesses by 18% in a carefully controlled study. This implies huge potential for better public health and cost savings from sick leaves, with a simple intervention against airborne infections.
yle.fi/a/74-20089670
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/255366424800
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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/zekle…
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/shigemat…
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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.
Update on our house’s NK-206A-3 CO2 Controller after a year of heavy use for IAQ. Here’s a time lapse of checking calibration a year ago: in mid 2023 all converged to within 50ppm of calibrated devices in all ranges. youtu.be/7U9UcuSQ6a0?si=GJxc…
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The NK-206A-P1 transmitters on 2 out of 5 of our devices drifted off quite a bit 200-500ppm. Luckily, the start and stop concentrations are completely unrestricted. If you know what readout ambient is, you can set it to ventilate any time there are more than 0 people in a space.
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Probing and debugging a central air system with a CPC is mindblowing. 100 hours (and going) of logs - N95 companion(to identify leaks around MERV16 filters) and from a full range CPC machine (for something resembling filtn efficiency…if and when the leaks are all stamped out).
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The in-depth look at the ZM9233, ZM100, ZM7711 and ZM95S is delayed. We planned to solidify different soft gasket mask designs in different configurations before cutting them with a waterjet and observing the cross section shspes. Since the dynamics of gaskets aren’t visible from the outside, and since doing this with radiology would probably be costly, the idea was to stiffen the seals in place and cut cross sections. The specimens would include a Marcio mask from China, an Akkair, 4 ZiMi models, a Shigematsu gasket disposable, a Dobu N95, two Koken disposables, and a few others. Some are not gasketed masks at all. The idea was to solidify a few masks as they are in their respective packages, then solidify a few more while they’re donned on static headforms, solidify a few while they’re on an expressive/moving headforms, and solidify a few after they’re doffed. We assumed the hard part would be the statues/headforms or getting freeze frames of headforms in motion. There might be a lot of ways to do that, but the part that we’re stuck on is finding a stiffener that works on these materials and can make them as hard as a thin walled polycarbonate package. If anyone knows how to do that, let me know or try it yourself.
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Data sparse zone so just by early results and gut feeling - the top of the line is still probably ZM9233 and ZM100, not Zimi One. The main reason is the narrower gasket on the One. Even though ZM9233 and ZM100 are considered medium and large, their wider soft gaskets relative to Zimi One could in principle allow for more head sizes/shapes to immediately fit without adjustment after donning, (if the in-package loop length were made smaller or the loop material was changed). The Zimi One gasket has less room to accommodate variation in face shape.
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