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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 you are making them look comparable, when they are not.






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?


You could start by adjusting your given filtration ratios by predictable leakage based on the type of mask. It's wholly misleading to rate the filtration potential of an earloop mask as equivalent to that of a 3M Aura.

Not exactly.. it really depends on the situation.

For example an ASTM 2 or 3 surgical mask fabric has a filtration of 98%+

On my face I have a leakage of about 21% or PFE of 79% when worn normally.

With an ear saver, it jumps to 91%.

With a mask brace, it jumps to 98%.

So it really is about the fit.

If I put leakage % it would vary from person to person and many people would be mislead by this.


> On my face I have a leakage of about 21% or PFE of 79% when worn normally.

> With an ear saver, it jumps to 91%.

> With a mask brace, it jumps to 98%.

I had no idea it could vary so much for surgical masks. I’d be curious what range of leakage people could typically expect for other designs such boat-shaped KF94 or flat-fold KN95 masks.

Fit seems important enough to deserve a mention in the intro paragraph at the top of the home page. A more detailed explanation, including the example you gave of how much it can vary for even one person, could go in the “Click here” link to the full testing methodology.

Thank you for doing this, by the way, rare to see a manufacturer test so far beyond their own masks. It clearly takes resources to do this and is a great service to all of us who have been relying on guesswork.


Okay I put a disclaimer right on the front and we are typing up an explanation right now. Thank you for this feedback!

https://www.armbrustusa.com/pages/mask-testing


thanks! all the notes about fit will be very helpful, including how to use the extra accessories you mentioned above.

For example I found this study on beard length which made me reconfigure my facial hair: https://www.nature.com/articles/s41370-021-00337-1

The charts in that paper also make it seem that n95 *typically* has a much better seal on the face which is worth noting.

I also wonder if the breathability you're measuring affects filtration, given imperfect fit. I would imagine that worse breathability would cause more air to flow around the mask rather than through it.


How did you determine those percentages?

Using the industry standard TSI PORTACOUNT® RESPIRATOR FIT TESTER 8048

It measures the air outside the mask verses inside the mask.

https://tsi.com/products/respirator-fit-testers/portacount-r...


Do you have the same measurement for you for an N95 with the typical elastic straps that you can share?

Yes but it differs from model to model.

I get as low as 80% and as high as 99% on my face.

Fit is a big deal because it's personal and hard to communicate. I think it was Amazon that found when scanning their workforce that they discovered 29 different face shapes!


> but they don't have a $250k mask lab to make sure the fabric is good

Hard to argue against that, but on HN I'm sure someone's gonna try :-)



hahaha got me on that one.

You could add a clear statement to the testing procedure popup that you are measuring the fabric only, and that (except for N95) the filtration of a mask is strongly dependent on fit and leakage.

Okay working on this now.. thanks for the suggestion. I should note that even N95 is extremely effected by fit. I've gotten as low as 80% filtration on a flat-fold N95.

Unhhh, fit and leakage matter a lot for N95 too.

Done

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.


Okay I put a disclaimer and typing up a post to link to LMK what you think: https://www.armbrustusa.com/pages/mask-testing

Thanks!

https://www.armbrustusa.com/blogs/news/mask-fit-vs-filtratio...

Oh, excellent update!

(It might be a good idea to break your database into two sections: one for N/KN/KF respirators and one for other masks.)

I also notice that you have a "collections" page

https://www.armbrustusa.com/collections/

That page has a very helpful section, "USA made N95 masks and KN95 respirators".

https://www.armbrustusa.com/collections/usa-made-n95-masks-r...

Exactly what we need. Two questions:

1. Aren't all N95 "masks" actually respirators? 2. Why do you offer "made in USA" KN95 (Chinese standard) instead of an Armbrust branded N95?

Thank you for doing this!


Hey, I think it's a lot more clear now :)

woot

These are good points. Working on rewording this now.

Perhaps you could add a “fit ease” row to your scoring? Masks with head straps could have a check and others could have a ? or something.

yes i could make a mask out of plastic film and it would have 100% efficiency

this probably explains why in these results, most adult masks have a pass rating, but most kid masks have a fail rating



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