You do need fancy equipment, but not quite that fancy. The one thing you absolutely can’t do it without is a nebulizer. This is a sort of modified spray bottle which converts liquid into aerosol. A regular spray bottle won’t work, because the droplets it produces are too large. The nebulizer I have works by having a channel which pulls liquid up and suspends a drop of it in the path of bursts of air, which you produce by squeezing a rubber bulb. This is an expensive item because it’s in short supply, but it’s a simple plastic part that would be very cheap if it were made in bulk, and it doesn’t seem impossible for someone to make a replacement home with hand tools and some expertise.
(A commercial fit-test kit will typically contain two nebulizers, when you only need one. The reason for this is because if you’re following the formal procedure, you first use a low-concentration version of the aerosol to make sure the person has a working sense of taste, then a high-concentration version for the real test, and if you’re testing a bunch of people in a row you don’t want to have to clean out the nebulizer each time. For home use, you only need one.)
(The liquid you put in the nebulizer is just saccharin in water; you might as well use a bottle that’s labelled as being for fit tests, but if you can’t get one you can get saccharin powder at a grocery store and mix it with water yourself. Some test kits use denatonium aka Bittrex instead, supposedly because some people can’t taste saccharin. A saccharin test is much more pleasant. I noticed that saccharin solution sometimes clogged the nebulizer, by leaving a crystalline residue when it dries out, and denatonium doesn’t.)
The formal fit test procedure also uses a hood, which holds aerosol in place while you hold your head at various angles and read a passage aloud, in case gaps open only while you do that.
When I’ve administered fit tests to people, about half fail. Cheap KN95s usually fail by having big gaps around the edges, which can be fixed by taping them down with medical tape, if you really need to. Rubber interface P100s fail by not having the straps tight enough or by having incorrectly installed filters.
I have an instant pot that can usually do a good job of turning water into mist. If an atomizer doesn’t work, how about simply creating steam with my instant pot?
I don’t know the physics of what happens in an instant pot very well, but probably not; I would expect any heat-based method for producing mist is probably going to be leave the solutes behind. But this is easy to test; just saturate some water with saccharin, turn it on, and see if (without a mask) you can taste saccharin in the air.
N95s with a thick edge, like the 3M 8210Plus, seem more likely to fit than the tent-style KN95s. P100s with a rubber interface have had a pretty good (but not perfect) success rate, conditional on the straps being tight enough to bend the rubber a little. A Narwall mask can be checked for fit without using a fit test kit, by covering the input vent with your hand, breathing in and felling the pressure (but that kind of mask is incompatible with glasses).
A seal check (the procedure you mentioned) can’t replace a fit test. For maximum protection, full-face respirators like the Narwall seem to require a quantitative fit test to be performed (rather than a qualitative fit test which is performed using a nebulizer). Unfortunately, the Narwall isn’t designed for the quantitative test, and so, it can’t be fit tested.
My own personal experience with (non rubber/P100) respirators is that one with headbands (rather than ear loops) and a nose clip + nose foam is more likely to seal well.
To minimize the risk of getting counterfeits, it’s probably better to buy from a trusted retailer and prefer respirators for which the manufacturer offers some validation procedure (e.g. this one).
You do need fancy equipment, but not quite that fancy. The one thing you absolutely can’t do it without is a nebulizer. This is a sort of modified spray bottle which converts liquid into aerosol. A regular spray bottle won’t work, because the droplets it produces are too large. The nebulizer I have works by having a channel which pulls liquid up and suspends a drop of it in the path of bursts of air, which you produce by squeezing a rubber bulb. This is an expensive item because it’s in short supply, but it’s a simple plastic part that would be very cheap if it were made in bulk, and it doesn’t seem impossible for someone to make a replacement home with hand tools and some expertise.
(A commercial fit-test kit will typically contain two nebulizers, when you only need one. The reason for this is because if you’re following the formal procedure, you first use a low-concentration version of the aerosol to make sure the person has a working sense of taste, then a high-concentration version for the real test, and if you’re testing a bunch of people in a row you don’t want to have to clean out the nebulizer each time. For home use, you only need one.)
(The liquid you put in the nebulizer is just saccharin in water; you might as well use a bottle that’s labelled as being for fit tests, but if you can’t get one you can get saccharin powder at a grocery store and mix it with water yourself. Some test kits use denatonium aka Bittrex instead, supposedly because some people can’t taste saccharin. A saccharin test is much more pleasant. I noticed that saccharin solution sometimes clogged the nebulizer, by leaving a crystalline residue when it dries out, and denatonium doesn’t.)
The formal fit test procedure also uses a hood, which holds aerosol in place while you hold your head at various angles and read a passage aloud, in case gaps open only while you do that.
When I’ve administered fit tests to people, about half fail. Cheap KN95s usually fail by having big gaps around the edges, which can be fixed by taping them down with medical tape, if you really need to. Rubber interface P100s fail by not having the straps tight enough or by having incorrectly installed filters.
I have an instant pot that can usually do a good job of turning water into mist. If an atomizer doesn’t work, how about simply creating steam with my instant pot?
I don’t know the physics of what happens in an instant pot very well, but probably not; I would expect any heat-based method for producing mist is probably going to be leave the solutes behind. But this is easy to test; just saturate some water with saccharin, turn it on, and see if (without a mask) you can taste saccharin in the air.
I tested it and you are right, the mist produced had no effect.
My answer links to a paper claiming that aroma diffusers can work well but humifiers, spray bottles, and spray bottles did less well.
Do you have tips on how to not fail without having one of these test kits? Which N95s work best? Do rubber P100s tend to fit better?
N95s with a thick edge, like the 3M 8210Plus, seem more likely to fit than the tent-style KN95s. P100s with a rubber interface have had a pretty good (but not perfect) success rate, conditional on the straps being tight enough to bend the rubber a little. A Narwall mask can be checked for fit without using a fit test kit, by covering the input vent with your hand, breathing in and felling the pressure (but that kind of mask is incompatible with glasses).
A seal check (the procedure you mentioned) can’t replace a fit test. For maximum protection, full-face respirators like the Narwall seem to require a quantitative fit test to be performed (rather than a qualitative fit test which is performed using a nebulizer). Unfortunately, the Narwall isn’t designed for the quantitative test, and so, it can’t be fit tested.
https://tsi.com/getmedia/3d247f13-bb31-4ec5-921b-92aa6360cc4c/ITI-032?ext=.pdf
https://www.youtube.com/watch?v=2xyNg2s1u7c
This might be better as it’s own top level question. How about creating the question yourself?
My own personal experience with (non rubber/P100) respirators is that one with headbands (rather than ear loops) and a nose clip + nose foam is more likely to seal well.
To minimize the risk of getting counterfeits, it’s probably better to buy from a trusted retailer and prefer respirators for which the manufacturer offers some validation procedure (e.g. this one).