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Show HN: I bought and tested the filtration of every mask on Amazon

armbrustusa.com

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Re: Show HN: I bought and tested the filtration of every mask on Amazon

#122

I've spent about 1,000 hours on this with my team using a very expensive (~$250k) lab and I'd love for this to be a great resource for people when choosing a mask. The heavy lift we are doing here is around our particulate filtration efficiency test in which we do either the NIOSH N95 NaCL (0.3 micron) test or the ASTM 0.1 micron latex particle test. I'd love HN feedback on how we improve the interface and make this…

I read through your "methodology", and it seems to be too simple to explain your pass/fail results. For example, you fail this mask: https://www.armbrustusa.com/blogs/mask-review/kn95-arun-flat... even though it seems to meet the filtration and breathability standards, but is still listed as having failed.

I guess maybe you explain the failure in the video, and maybe there's a good reason that it failed, but you're asking me to waste a bunch of time watching videos to understand information that could have been provided in print. It doesn't make me trust you.

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#123

Earlier quoted context omitted.

Most of the point of wearing a mask is to prevent you from unknowingly spreading COVID to other people. Many stores I visit have signs prohibiting vented masks.

I've been wearing a surgical mask on top of a valved N99 some of the time. That seems to satisfy. Maybe I could put more serious filtration material over the valve though. I would like to find some affordable PAPR's (powered air purifying respirators). I see a number of places claiming to make them, but none seem that actually available to buy. It might be interesting to measure the amount of CO2 inside a mask after…

I don't see how CO2 or any other exhaled gasses could possibly be an issue if the volume of air inside the mask is significantly smaller than the volume of a breath, which it is by a large factor.

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#124

Earlier quoted context omitted.

I looked at the linked page and it had a big list of masks, each of which linked to a page about that mask with a picture but no information such as test results. Was that intended? Could you just ditch all the fancy web design and have a big table with test results for each mask, with an ordering link for the models that you sell? That would be awesome. It would be great if you also sold the stuff you use for testin…

Testing masks is very specialized and all in I've spent about $250k on the mask lab. I just bought a new machine that costs about $90k. Here's an overview of the machine: https://www.youtube.com/watch?v=vpjajJrDWBk

Thanks, I'll watch the video when I get a chance. My idea was to basically reproduce the setup in Joel Amilcar's PhD thesis (https://ir.uiowa.edu/etd/2002/) using an off the shelf air quality sensor (PM2.5 with the hope of being able to extrapolate below that size), using a salt spray nebulized with vape gear. I didn't have any good ideas about how to control the particle size (this isn't my area at all) so had hoped to get some advice at some point (let me know if you have any thoughts). I had remembered reading about a guy on Youtube who did some tests like that but never managed to find the channel. Maybe it was yours! Someone else here mentioned Aaron Collins so I will have to check his videos too.

I think it would be great to have easily reproduceable, low cost test equipment available at shops and clinics because the quality of masks (even of a specific make and model) is likely to vary between units. You might find a good mask with your tests, and then find that your next order of the exact same mask is crap. So you have to keep testing. Maybe it is less bad now. I was interested in this more when masks were in very short supply, but then I managed to get a few boxes of them, and set the testing idea aside.

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#125

I've spent about 1,000 hours on this with my team using a very expensive (~$250k) lab and I'd love for this to be a great resource for people when choosing a mask. The heavy lift we are doing here is around our particulate filtration efficiency test in which we do either the NIOSH N95 NaCL (0.3 micron) test or the ASTM 0.1 micron latex particle test. I'd love HN feedback on how we improve the interface and make this…

I read through your "methodology", and it seems to be too simple to explain your pass/fail results. For example, you fail this mask: https://www.armbrustusa.com/blogs/mask-review/kn95-arun-flat... even though it seems to meet the filtration and breathability standards, but is still listed as having failed. I guess maybe you explain the failure in the video, and maybe there's a good reason that it failed, but you're a…

Read their methodology,

> A good example of this is in the text written on the front of N95 and KN95 masks. The standards for each of these masks demand that very specific information be printed on the device. If a KN95 mask does not have the manufacturer name and the standard number they are meeting (GB 2828-2019 or GB2828-2006), then they cannot be considered KN95 masks

Such masks are marked failed. My guess is thats what happened here.

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#126
post #60

Earlier quoted context omitted.

Most of the point of wearing a mask is to prevent you from unknowingly spreading COVID to other people. Many stores I visit have signs prohibiting vented masks.

I'm pretty sure a vented mask is at least as effective as a cloth or surgical mask in that regard, both of which mostly contain the aerosol spray rather than actually filter out small particles. I doubt the stores you go to require true respirators? Apparently the CDC agrees: https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use... > Yes, an N95 filtering facepiece respirator will protect you and provide sourc…

I'm sure its fine for most situations, but you should be aware: below that entry it states that elastomeric respirators (like you are using with P100) are not included in that category:

> Until more is understood on exhalation valves, elastomeric respirators with unfiltered exhalation valves should not be used as source control in surgical and other healthcare settings due to concerns that air coming out of the exhalation valve may contaminate the sterile field.

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#127

I've spent about 1,000 hours on this with my team using a very expensive (~$250k) lab and I'd love for this to be a great resource for people when choosing a mask. The heavy lift we are doing here is around our particulate filtration efficiency test in which we do either the NIOSH N95 NaCL (0.3 micron) test or the ASTM 0.1 micron latex particle test. I'd love HN feedback on how we improve the interface and make this…

on the 3M aura, "made in american". otherwise great site

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#128

Earlier quoted context omitted.

Your filtration test appears to be only testing the mask fabric, but not the fit. I see a number of surgical masks over 95%. I don't think that would be possible in practice, because of leaks at the sides and top. I'd expect more like 50%. But, you don't appear to have the equipment to do a fit test. Refer to the 3M video on how to fit test an N95. I realize that N95 and surgical masks have different standards, but y…

A good mask needs both fit and filtration... most people can put a mask on, check for air gaps and see how well it fits, but they don't have a $250k mask lab to make sure the fabric is good. We are just solving for the filtration and letting people figure out the fit. But, you make a good point, in the videos I try to point this out but we could do better. Where could I add this to make this more clear?

I think it should be made way more clear - and here I take the opposite stance of the person you're replying to.

Change title to "Comprehensive Mask Material Testing" or "Comprehensive Mask Fabric Testing" or similar.

Similarly; "...that's why we're testing the filtration capabilities of every mask in our laboratory"

At some point (on the front page, above the fold) there could be a small notice box explaining the difference, or ?-link or tooltip to read more.

I think a lot of the suspicion you're facing in this thread wouldn't have been there if it weren't for that ambiguity, and the need to go into deep content to resolve it.

For someone who just browses to your site and spends 5 min finding "the best mask", they would never realize as it is today.

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#129

I've spent about 1,000 hours on this with my team using a very expensive (~$250k) lab and I'd love for this to be a great resource for people when choosing a mask. The heavy lift we are doing here is around our particulate filtration efficiency test in which we do either the NIOSH N95 NaCL (0.3 micron) test or the ASTM 0.1 micron latex particle test. I'd love HN feedback on how we improve the interface and make this…

Did you fail all the Chinese masks?

Re: Show HN: I bought and tested the filtration of every mask on Amazon

#130

Earlier quoted context omitted.

Thanks for noting, this was our old methodology and I will get that updated ASAP. We are now removing the subjective feedback and only talking objectively: 1) Does the mask pass the claimed PFE (particulate filtration efficiency) standard that it claims to pass? 2) Does the mask pass the claimed breathability (as stated in the standard they are claiming, ie N95, KN95, surgical)? 3) Does the mask meet other parts of t…

With regards to #3, I found it a bit incongruous that you failed some KN95 masks (like Boncare) for incomplete labeling, while allowing a mask to pass that met a standard that appears to be entirely of their own devising (the Lutema M95i [0]). This seems to be a bit unfair, given that they both performed well in the PFE and breathability tests. It seems like if Boncare decided to call theirs an “MN95” mask, it would…

If a product claims to be X and doesn’t meet the X standard, it’s not an X and it’s entirely fair to mark it failed.

Otherwise, everyone would just mark their mask however the hell they wanted, benefit in the market, and as long as they passed the MN95 standard, they’d get a passing mark on their “N95” masks.

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