It's called MultiVapor. Creative name, I know, but it might be useful if you get Conyer'd by a chemical spill or something else like it.

https://www.youtube.com/watch?v=-UEKtJRI4pk - New video on the qualitative fit test procedure by @ghhughes@zeroes.ca

#CPCSupport

If you haven't seen it, check out @ghhughes@zeroes.ca new video on PAPRs: www.youtube.com/watch?v=MdbdZt8x6Ps

@CPCSupport@fedia.io #cpcsupport #CPCSupport

Well... a lot has happened in the past month. Let's go over them.

---

Another chemical incident!

Right on cue, the Conyer's Chemical Plant caught fire. A lot of people have been sharing this guide from 3M on choosing a chemical cartridge. As a reminder from this post, the color coding is pretty useless. Notice for example, that a lot of combinations use ANSI's "olive" color for any number of chemical cartridge combinations.

Really, the only thing you should pay attention to are the NIOSH abbreviations on the chemical cartridge label, listed here.

---

Fitting negative-pressure respirators with a beard?

Normally, fit tests and OSHA would insist on beard-users using loud, powered-air-purifying respirators to stay safe, and not catastrophically compromise their fit factor. However, @ghhughes@zeroes.ca noticed that the NIOSH NPPTL was looking into the fit every day, negative-pressure respirators, with beards, with the help of a latex band. The paper that first brought this idea up was published 2021 in Nature, linked here.

---

And finally...

This paper, which claims to be an N95 RCT. Though astute readers might notice that, unlike other RCTs which simply (and ineffectively!) replace surgical masks with respirators, this RCT insists on qualitative fit tests, exclusion of people with beards, and splitting of respirator users into a group where the respirator is worn only part of the time, and a group where it is worn all of the time.

The group that wore the respirator all the time had the least amount of infections, which should come as no surprise to anyone aware of 29 CFR 1910.134. Despite rigorously following the OSHA protocol, (beards, fit tests, respirator program and all) the paper did not cite it. Again, emphasizing the adage that a respirator only works when you wear it.

And yes, based on this paper, qualitative fit testing is a totally viable type of fit test. No need to insist on a PortaCount fit test to stay safe.

It's #respirator week at #NIOSH , So let's dive into a common question, does one-way masking work? 🌬️

Explore how effective one-way masking is against #COVID-19 in Part 4 of our series. Learn about different mask types and their protection levels.

Read more:

https://airsupportproject.com/does-one-way-masking-work-covid-19-series/

#CPCSupport

No, Peter Tsai did not invent the N95, contrary to what rumors would have you believe. Nor was it invented in 1970.

It was actually quite recent... well... relatively speaking in terms of labor issues. 1995. Rhymes, doesn't it?

https://en.wikisource.org/wiki/NIOSH_Guide_to_the_Selection_and_Use_of_Particulate_Respirators_Certified_Under_42_CFR_84

This is going to be a short one, but hey, it has to be said.

• It is possible to fit test a full face respirator with a crude adapter made of duct tape. Just make sure to remove the nosecup so you don't miss sampling the exhalation valve. See this for more context.

• And hey, you might as well do a fit test with the nosecup, just to be sure it all fits nicely.

• A mysterious fit test failure with my PortaCount-connected-to-a-full-face-respirator also happened to be caused by a broken exhalation valve. Who knew?

• For those interested, this particular failure occurred after deep breathing, and during the side-to-side exercises.

• So, if you even a little suspicious your exhalation valve has been slightly warped from use, best to assume it has been.

Fun fact: That giant hole made through the pictured full-face-respirator's lens is an adapter from Dynatech Frontier. If you had any idea what I just said, please go to the microblog section through this link.

Wow, time flies. Has it really been over a year since a train in Ohio derailed and spilled a bunch of Vinyl Chloride everywhere?

Well, hopefully, it won't ever happen to you, but if a train happens to derail in your area, remember this:

DO NOT RELY ON CHEMICAL CARTRIDGE COLOR-CODING.

All the cartridge color information online is wrong or outdated. And the US government's 42 CFR 84-approved standard, ANSI™ K13.1-1973, provides a generic color for combinations of chemicals not listed in the (paywalled!) table.

This leaves, unfortunately, the tedious read of your respirator's cartridge packaging to determine what volatile chemicals it blocks.

It'll go something like: "AG/AM/OV/CO," or maybe it'll just tell you what the chemicals are, which, in this case, is "Acid gas/Ammonia/Organic Vapors/Carbon Monoxide."

• Here's a guide from NIOSH™ for the acronyms..

• You'll also want to check the NIOSH™ pocket guide for more respirator use instructions. Be aware: no matter what it says, you should not use a cartridge that doesn't have the corresponding chemical listed on its packaging and documentation.

• Don't use cartridges if the use-indicator is darkened (check your respirator's documentation for details).

• And of course, always check the manufacturers website, to get chemical cartridges from official vendors.

• The NIOSH TC# should start with TC-23C (chemical cartridge) or TC-14G (gas mask).

• "Canisters" and "cartridges" can have different color codes under K13.1-1973. And sometimes, like with "Ammonia" and "Carbon Monoxide," they have the same color code. That's not confusing at all.

More fun facts:

• K13.1-1973 got revised in 2001. It's called ANSI Z88.7-2001, mostly to address 42 CFR 84 updates in 1995. It's the new K13.1-1973, and that one's official.

• Chemical cartridges are approved by NIOSH™, the same government entity that approves N95™s. Unlike the N95™ though, chemical cartridges are not trademark-able. So you'll have to be careful where you get your cartridges form.

• Did you know that ANSI K13.1-1973 has an alternate color for P100™ filters? They're normally magenta in color under 42 CFR 84, but the ANSI standard allows for purple P100™ filters.

And now you know why the 3M™ 7093 P100™ filter is purple.

• There are max use concentrations for chemical cartridges. 42 CFR 84 says you shouldn't use an ammonia cartridge if the concentration is above 300 ppm. In that case, officially, you would have to wear a firefighter's SCBA.

Yes, you can fit test SCBAs with a CPC/PortaCount too. Filters are added to the mask and it's tested in negative pressure mode...

(Speaking of firefighters, did you know a lot of US law relies on NFPA™ guidelines which are also paywalled? Seems like a tradition, I guess)

• 42 CFR 84 states that, at the worst possible concentration, chemical cartridges can at worst filter 90% of a given chemical in the air. There's no easy way of testing this, so you'll have to take NIOSH™'s word on it.

That's a worse show of performance than most N95™s do with particulates!

All this makes our prepper who only hoards gas masks for the apocalypse, but not for our entrenched, and evolving, SARS biohazard seem even more insane.

Even more insane if they insist that N95™s are trash...

but their hundred-dollar-plus-gas-mask-with-canisters-I-have-no-way-of-testing-so-I-have-to-trust-the-government-department-NIOSH™-who-also-certifies-N95™s?-in-case-the-government-fails

...is a perfectly reasonable form of protection. Despite the fit all being tested on the same OSHA-cleared equipment, like the PortaCount.

One more useless fact!

• The Federal Register, you know, the journal that holds all the CFRs for the president and stuff (the executive branch, if you recall civics class), was created when FDR was president.

If you have any Dynatech Frontier / Frontier Enterprises documentation, Dynatech Nevada software for the FitTester 3000, or documentation from PortaCount Pluses dated from 1998 and prior, reply here, or DM @fedivesefittester@fedia.social (on fedia.social, not .io)

#dynatech #portacount #CPCSupport

This thread is a work in progress, see open questions Need guidance?

Somehow, while half-asleep looking for info on respirator fit testing, I managed to also sloppily assemble a list of fit novel, interesting test protocols across various eras. Probably not of great use to anyone, including PortaCount users like myself (ironically)...

But, since Lemmy/The Threadiverse is in desperate need of niche, pedantic, semi-historical content, I might as well go to the effort to assemble it all here. I mean, who else is going to publish the stuff I've seen in the Federal Register?

This thread was originally also going to only include protocols that were designated across all fit test methods by regulatory authorities, but I might as well include them all here, for conveniences' sake. (Except CNP, cause this is /m/CPCSupport, and that's a whole can of worms...)

::: Open Questions

• Certain custom protocols that were made up for scientific papers are missing. I can't be bothered to add them at the moment, though.

• There may also be another country that has developed its own weird protocol, but that seems unlikely (given how long this list is...)

• We're not sure why fit test protocols changed over time. I mean, we can guess a motive, but not the data or experimental results that lead to these changes.

• We're also not sure why international regulators generally copy OSHA and remove 'grimace'. (What's wrong with grimace?!)

• It's up in the air which of these official protocols is the best. I'm placing my bets on the 1990s OSHA protocol, but maybe 'grimace' is really tough, who knows.

:::

Historical and Current Protocols, Mandated by law in the US

::: Current OSHA. 8 Exercises, Qualitative and Quantitative

1 minute per exercise, except for grimace (15 seconds)

1. Normal Breathing
2. Deep Breathing
3. Head Side to Side
4. Head Up and Down
5. Talking (use rainbow passage, or count)
6. Grimace
7. Bending
8. Normal Breathing

(Insert 'grimace' jokes here)

:::

::: Early 90s OSHA. 8 Exercises, Qualitative and Quantitative

This was part of the impetus for this whole thread. I found a document where exercises 6 and 7 aren't quite as you remember them today...

1 minute per exercise.

1. Normal Breathing
2. Deep Breathing
3. Head Side to Side
4. Head Up and Down
5. Reading (use rainbow passage, or count)
6. Bending
7. Jogging
8. Normal Breathing

:::

::: NIOSH/OSHA Protocol, 6 Exercises, Qualitative and Quantitative

I call this the "NIOSH" protocol because it's a protocol described in Appendix B, in the NIOSH Guide to Industrial Respiratory Protection. But according to TSI, OSHA apparently used this protocol for certain occupations well into the late 1990s, even after the 8-exercise protocols were made. Oh, bureaucracy.

1 minute per exercise.

1. Normal Breathing
2. Deep Breathing
3. Head Side to Side
4. Head Up and Down
5. Talking (use rainbow passage, or count)
6. Normal Breathing

:::

::: US Military Protocol, 5 Exercises

1 minute per exercise

1. Normal Breathing
2. Deep Breathing
3. Head Side to Side
4. Head Up and Down
5. Rotate Chin

:::

::: US Military Protocol, 6 Exercises

1 minute per exercise. Sourced from a TSI demo program found on Archive.org.

1. Normal Breathing
2. Deep Breathing
3. Head Side to Side
4. Head Up and Down
5. Rotate Chin
6. Jog in Place

:::

::: MESA Protocol, 4 Exercises, Qualitative

This was another major impetus for this thread. Before NIOSH, respirators were regulated by the Mining Enforcement and Safety Administration, and before that, the Bureau of Mines. Fit testing wasn't done in the early days, but by the 70s, this was the protocol we got:

2 minutes per exercise!

1. Nodding and Turning Head
2. Move Arms
3. Run in Place
4. Use Tire Pump

Is this scientifically backed? Who knows. (Foreshadowing...) :::

::: OSHA "Fast Fit Test Protocol" for Quantitative CPCs, 4 Exercises

This is a new protocol. Note: By the book, you'll also need to modify the sampling times when using this protocol. And not for the better...

By the book: 50-30-30-39 seconds

1. Bending Over
2. Jogging
3. Head Side to Side
4. Head Up and Down

Is this scientifically backed...? :::

International Protocols

::: Most of them, 7 Exercises, Qualitative and Quantitative

1 minute per exercise. The main difference between this and OSHA is that 'grimace' is removed. And sometimes they rearrange the exercises...

1. Normal Breathing
2. Deep Breathing
3. Head Side to Side
4. Head Up and Down
5. Talking (use rainbow passage, or count)
6. Bending
7. Normal Breathing

:::

::: EN 149, 5 Exercises

Made for Europe. 2 minutes per exercise. Kind of a hybrid between the MESA and OSHA protocols. Eh, not really.

1. Walking
2. Head Side to Side
3. Head Up and Down
4. Talking (Alphabet)
5. Walking

:::

::: Crash UM, 6 Exercises, Qualitative and Quantitative

1 minute per exercise. Significantly shorter than Crash UM.

1. Normal Breathing
2. Talking
3. Normal Breathing
4. Normal Breathing
5. Talking
6. Normal Breathing

:::

CPC Timings

::: Standard

8020 Actions	Timings
Mask purge	11 sec.
Ambient sample	5 sec.
Ambient purge	4 sec.
Mask sample	40 sec.
Total time per exercise	60 sec.

:::

::: 2-Minute Example

8020 Actions	Timings
Mask purge	11 sec.
Ambient sample	5 sec.
Ambient purge	4 sec.
Mask sample	100 sec.
Total time per exercise	120 sec.

:::

::: N95 (Slow)

Extra tubing necessitates longer timings.

8020A Actions	Timings
Mask purge	15 sec.
Ambient sample	15 sec.
Ambient purge	6 sec.
Mask sample	50 sec.
Total time per exercise	86 sec.

:::

::: OSHA "Fast"

On the first exercise:

8030 Actions	Timings
Mask purge	11 sec.
Ambient sample	5 sec.
Ambient purge	4 sec.
Mask sample	30 sec.
Total time per exercise	50 sec.

If you're using FitPro, you just have to click "Fit test with 2 ambient samples" and you'll be done with configuration. But just for the heck of it, let's keep going:

On the second and third exercise:

8030 Actions	Timings
Mask purge	0 sec.
Ambient sample	0 sec.
Ambient purge	0 sec.
Mask sample	30 sec.
Total time per exercise	30 sec.

Final Exercise

8030 Actions	Timings
Mask purge	0 sec.
Ambient sample	5 sec.
Ambient purge	4 sec.
Mask sample	30 sec.
Total time per exercise	39 sec.

You won't be able to do a 0 second purge/ambient time on an 8020, so the best time you can get is ~3 minutes on a 8020.

:::

::: Military Timings

Sourced from the TSI demo program.

8020 Actions	Timings
Mask purge	11 sec.
Ambient sample	5 sec.
Ambient purge	4 sec.
Mask sample	20 sec.
Total time per exercise	40 sec.

:::

::: Military Timings (N95??)

Note: The 8020M does not support the N95-Companion. However, these timings were left in the TSI demo program for some reason...

8020 Actions	Timings
Mask purge	15 sec.
Ambient sample	15 sec.
Ambient purge	6 sec.
Mask sample	50 sec.
Total time per exercise	86 sec.

:::

::: TL;DR

• Make sure to fit test. It is not a user seal check.
• If you think you've failed a fit test, you've failed.
• For everyday use, it's almost never the filter; replace the exhalation valve. :::

Users of elastomeric respirators are usually concerned about their filters. I mean, you change your filters in your furnace every year (or if you're paranoid, every season). Maybe you don't need to change it as often as an N95, but shouldn't you have to change your elastomeric filters, say every six months?

Well, I'm going to cover in later post why throwing out old, unused filters is, surprisingly, almost never necessary (but only if you aren't stressing it by grinding stone or removing asbestos... or anything else that requires a respirator), but in short:

It's almost never the filter.

But you know what does need changing every six months? That's just as exposed to dust as the filters? A piece of rubber that, if you fail to pay attention, can plummet your fit factor scores to single-digit surgical mask territory?

Notes When Fit Testing Your Respirator

Besides the commonly given advice to:

• Fit test, with the help of Bitrex/Saccharin + a nebulizer, or, if you're healthy, irritant smoke,

• fit test at regular intervals (which is usually how faulty exhalation valves and changing faces are discovered),

• and do user seal checks (located in your respirators manual, usually),

The most important thing to remember is never ignore failures.

• If you coughed, even slightly in, say, an irritant smoke test, you've failed the fit test and need to investigate what went wrong.

I had previously swapped an exhalation valve with one from another respirator, promptly forgot about it, and inadvertently swapped it back, assuming the irritant smoke test was faulty. It wasn't. After that, only regular testing with a CPC caught the failure.

If you do happen to only have a CPC, here's a telltale sign of exhalation valve failure:

• Do repeated exercises of Normal Breathing-Deep Breathing.

• Normally, after the first exercise, you'll notice a slight drop in fit factor when 'Deep Breathing' compared to 'Normal Breathing.' This is because there's an increase in filter penetration when 'Deep Breathing.'

• But, if the exhalation valve is leaking, you'll notice a 'Normal Breathing' score lower than a 'Deep Breathing' score, well into the third exercise and beyond.

• You'll usually notice this pattern on multiple attempts.

If your respirator isn't visibly damaged, replace the exhalation valve immediately. Alternatively, if you feel a stream of air leaking, your respirator does not fit and needs to be replaced with a different brand or size.

And of course, unless the exhalation valve is absolutely destroyed, you won't be able to detect this mode of failure on current CNP fit testing machines. Makes you wonder why OSHA is still allowing this style of fit test...

::: Edit: It's a little late to opt out of Discord forced arbitration, unless you've recently created a new account. Unfortunate, but in the meantime, you might want to watch out for regulations in your state's legislature...

Sidenote: If you're still on Discord, make sure you opt out of mandatory arbitration ASAP! And maybe consider joining Matrix where they don't have a skeleton in a closet?

Have you heard of another social platform (corporate or not) mandating arbitration? :::

::: Edit 2: If you are a Bluesky lurker... Please follow @ap.brid.gy Explanation. Oh yeah, they mandate arbitration too. :::

Back on topic...

This should hopefully be the last equipment wanted post. Yes, I know they're a bit annoying, but these things are just hard-to-find, you know?

In case you're wondering, yes, we're still looking for a PMLT/TDA-99M. Any leads or demos, as always, should go to DMs. But ATI isn't the only vendor making photometer-based fit testers. Okay, they used to be, when their first competitor went out of business, but guess who stepped up in their place...

Yep. Here's the manual for the 8587A. IIRC, it's been described as a miniature version of the 8130A, the giant filtration tester used by respirator manufacturers. Except, this one acts a little more like a PortaCount, in that you can fit test with this thing!

The 8587A doesn't include a vacuum pump, so that's a little disappointing, but in all other respects, it's just like a PMLT/TDA-99M with regards to requiring oil-based aerosols and a hood for the person being tested.

DM links: @fediversefittester@fedia.social (Mastodon, fedia.social) or @fediversefittester@fedia.io (Lemmy, fedia.io)

If you've been thoroughly reading /m/CPCSupport, you might be aware of the most common accessory for the 8020A, the N95-Companion, which was integrated into later models of the PortaCount. But did you know there's another, more obscure accessory for the PortaCount?

Consider yourself lucky! ...if you manage to find this accessory at a discount. I could only find one unit on the largest auction site for an unreasonable price, and they haven't shown up in any government auctions yet.

The 8120 is believed to be TSI's answer to the ATI's PMLT/TDA-99M, an already rare fit tester. So unsurprisingly, the 8120 is almost nonexistent. You can't even more than half a page worth of results on a Google Image Search.

::: What is this thing?

The accessory essentially adds standardized elastomeric testing involving stuff like the drink tube and the exhalation valve, features of the TDA-99M, to the PortaCount. Oh, did I also mention:

• It was released after the end 8020A manufacturing, yet the 8120 still supports it?

• But it doesn't support the 8040.

• And it's placed 10 model numbers behind the super-expensive 8130, which has the 8119 accessory?

Curious...

Here's the manual, if you're interested. And the 8120 is not just limited to super expensive CBRN respirators either; here's a manual for the 3M Bayonet adapters, which no one has been able to find yet.

:::

Yeah, even if you find an 8120, with no adapters, you're not going to be able to use it for its intended purpose anytime soon. But feel free to let us know if you've found or acquired one.

This is perhaps the ~~rarest~~ aerosol based quantitative fit tester out there. We'd appreciate getting any leads on Craigslist or something.

"PMLT" is the model name given to the civilian version AFAIK, (manual here), while "TDA-99M" is the military model, sorta like the 8020A and the 8020M for the PortaCount.

Yes, we already know about the three available on the biggest auction site, but unfortunately, they are all missing the components needed to do a quantiative fit test. One of the biggest ones is the shroud...

...not to mention all the tubing required.

::: Why is it rare? Photometer-based quantitative fit testers used to be the only option to do a quantitative fit test for about a decade before the PortaCount. ATI was one company that provided equipment during this era, along with another company that has since gone out of business... but since about the late 80s, the PortaCount, along with other CPC and CNP machines, basically displaced any market for these expensive machines. ATI continues to exist as a sort of competitor to TSI in other related HVAC/aerosol products, but with a significantly attenuated role in the quantitative fit testing market. :::

I recommend going through the manual, and DMing @fediversefittester@fedia.social (or @thetester@discuss.online on Lemmy) if you have any information.

A.k.a. the PortaCount's 'check engine' light

TSI claims the 'service' message appears with low alcohol or moisture-laden wicks, high temperatures, and if none of those are true, with dirty 'internal lenses.' Seems sensible enough...

...but, we've already covered how to clean the 'internal lenses', and changing the alcohol cartridge is easy enough, so what really is causing the 'Service' message to appear? And for that matter, why does it appear when it's hot outside (as seen in the troubleshooting guide)?

As far as I can tell, with one well-used PortaCount that has had every possible thing changed about it not involving the laser, including, but not limited to, changing the filters, and of course, cleaning the sampling cone 'internal lenses', leaving only the laser itself. Which leads to a somewhat profound conclusion:

The 'Service' message appears when the PortaCount photodetector thinks the laser is off its calibration.

It would explain why moisture and hot temperatures, presumably especially in humid climates, would cause the 'Service' message to appear. But it also may appear when you've been using the PortaCount for too long, presumably due to laser drift as the hours on the laser diode increase. So... don't do that.

Some (somewhat obvious) Tips for Avoiding Excess Hours on the Laser

Assuming you've done all you can to eliminate other causes of the 'Service' message, if it actually is caused by the laser drifting, you will have to spend a arm and a leg trying to get it recalibrated by someone with the proper equipment, which around $800-$1000+. Ouch. Here's how to avoid that:

• If you ever need to do the drying procedure done in the PortaCount manual, which essentially involves putting the Zero Check filter on, and putting the PortaCount into 'Count' mode to stop it from turning off until 2-24 hours have elapsed, well, don't do that. Instead, leave the PortaCount off for a week, (with its cover on to protect the sampling cone), to allow the alcohol to evaporate without having to put hours on the laser counting nothing.

As far as I can tell, leaving the PortaCount off to dry for a week works just fine, even in my somewhat rainy climate, but your experience may vary.

• Leave the PortaCount off when you're not using it.

I'm assuming, unlike light bulbs, turning them on and off constantly isn't going to shorten a laser diode's lifespan, but again, your experience may vary.

And, in addition to laser manufacturers being mum about life expectancy details, no one really knows what sort of laser TSI uses, and no one really wants to open their PortaCount to check either, due to the relative rarity of PortaCounts themselves. I guess that leaves the last tip for this thread:

• Try and maximize your usage of your PortaCount each session.

It seems it's all we can do, really.

There are three avenues to getting a PortaCount: eBay, or, if you're in the US, government auctions and Craig's List.

Personally, I haven't had much luck with Craig's List, but who knows, you might be luckier where you live.

Regardless of which avenue you choose to buy a PortaCount, here are some things to keep in mind:

• When buying on eBay: DON'T make things worse for others by overpaying. Always check 'completed listings' and 'sold listings' first. Unless you're buying an 8030 or newer, in which case, go nuts. (Note: If you're buying an 8030 or newer, the alcohol cartridge and N95-Companion sections do not apply to you!)

• Calibration date: Very important. It's found on the bottom of the PortaCount, and ideally, it should be dated 2015 or newer. PortaCounts older than this have not been serviced properly, and may have pump damage. A sign it's newer is if the bottom two circular filter covers are flathead screws instead of hex screws.

• Parts missing on the PortaCount: If your PortaCount is missing covers for the bottom two filters, that's pretty bad, and a sign that it might not be working. Avoid.

• The power supply: If your PortaCount does not have a power supply, get a 5V center-positive power supply, with a 5.5x2.5 mm barrel plug. The power supply, to be safe, should provide at least 2 amps, and TSI provides a power supply that provides 5 amps. Power supplies are a commodity, so don't limit yourself.

• Zero Check / HEPA Filter: Zero Check filters are easily damaged, so don't be fooled by fit factors less than 50,000 from an old filter. Just get a new one. Cheapest vendor is ETA, but you can also get them from TSI themselves or even AccuTec-IHS.

• Tubing: If your PortaCount comes with no tubing, or a damaged tube, you could buy new 1/8" ID 1/4" OD tubing and connect it to be sample port, leaving the ambient port empty. That will provide a valid fit test. But honestly, it may just be easier in the long run to buy the three-pack of tubing from AccuTec-IHS for $97. You won't have to worry about the ID/OD tube length, and you'll have two more tubes to prevent build up of condensation. Faling that, you can always buy more tubes from TSI or AccuTec-IHS for $40-45.

• Probes and probe installer: Your PortaCount will probably not come with them, unless the N95-Companion (which will probably cost as much as another PortaCount). Since the probe installer is a standard off the shelf part, both TSI and Accutec-IHS produce them. However, neither are really that cheap, so you might be better off just DMing someone for probes and the probe installer. (Hint hint)

• NEW: Probe Acquisition Tips: Turns out the standard OD tubing the PortaCount uses corresponding standard OD tube parts. The parts you should be paying attention to are: 4mm Stud Push-On Retainers OD Phosphate and Canvas Snap Fastners, 3/8" Post. Note, however, that since this is industrial materiel, you may not be able to get probes for much cheaper than TSI themselves, so better to DM someone for bulk purchases (hint hint, again)

• N95-Companion: ALWAYS buy with the sampling pendant, and the water-trap tubing / headphone-jack like cable. These accessories are a pain to get otherwise (you'll get them from REPSS). And ideally, it should also come with the annoying interconnect cable and a bit of spare ID/OD tubing to connect the PortaCount with the N95-Companion. If you don't have the annoying interconnect cable (or ID/OD tubing), it's not the end of the world, but you may have to DM someone (hint hint).

• Alcohol Cartridge: You can try buying the TSI P-Trak alcohol cartridge (Disclaimer: I have not tested this), or you can go to REPSS and buy the alcohol cartridge from them, for $70-$90 respectively.

• Reagent Alcohol: It's cheapest just to get it from a chemical vendor. Higher purities, beyond 99.5%, are okay. It's just not worth it to get it from the CPC vedors themselves at the moment. It's another commodity.

• Bonus Tip 1: Save money on shipping by only choosing one vendor to supply you with all the missing, obscure parts you need, except for things that are basically common commodities, like alcohol and power supplies.

• Bonus Tip 2: Check if all filters are in place. Use hex / flathead screws on the circular filters, and Philips-head for the rest (NOT JIS, look it up). Be careful not to lift the top too quickly; there's a ribbon cable you need to disconnect.

• Bonus Tip 3: If you plan on opening the N95-Companion, DON'T remove the three center screws. They attach the charged particle separator, and you'll have a hard time putting it back in if you remove them.

• Bonus Tip 4: For PortaCounts newer than the 8020A, the 8030 does not have N95 support. You'll have to buy the models ending in 8. The 8020, 8020M, and all older PortaCounts, do not have N95 support. And as implied throughout /m/CPCSupport, the 8020A requires the N95-Companion for N95 support.

• Bonus Tip 5: Do not buy the 8010. They haven't been serviced since 2001.

I realized I hadn't properly discussed the definition of a "fit factor" in the last post, but since this is (IMO) important, basic mask information everyone needs to know, and since it is a prerequisite for understanding fit test exercises, I'm going to discuss it in a separate post without added jargon and confusion.

In CPC parlance, fit factors are how much cleaner a mask is inside, compared to outside. Hence the equation:

Fit Factor = Ambient Concentration / Mask Concentration

It seems cryptic, but it really isn't that hard if you imagine aerosol particles like apples inside the bucket vs outside the bucket.

How do we determine the number of "apples?" Well, that's the job of the CPC, in the form of particles per cubic centimeter of air.

Technically, we could use any particle detector, but CPCs are usually used due to their ability to detect a wide variety of indoor air particles, as well very small particles, well beyond what a laser can detect normally in dry, alcohol free air.

The number you get is essentially how much cleaner the air is inside the mask than it is outside. For example:

• A fit factor of 10 means the air inside is 10 times cleaner than outside.

Total Inward Leakage

A fit factor of 10 also means that there's a Total Inward Leakage of 10%. Which makes sense: if you have 10% of the count of apples outside the bucket equals the count of apples inside the bucket, then there are 10 times as many apples outside than inside. Here's the equation:

Total Inward Leakage Percentage = 1 / Fit Factor * 100

For example:

• For a fit factor of 20, 1/20 = 0.05, 0.05*100 = 5% total inward leakage.

Hey, that's the allowable filter penetration limit of N95 masks!

Assigned Protection Factor

There's a lot of smoke and mirrors on how assigned protection factors came to be, but if you ever come across this term in NIOSH or OSHA literature, just remember this formula:

Assigned Protection Factor = Fit Factor / 10

Fit Factor Assumptions and Qualitative Fit Tests

Okay, all the important equation parts are done, so if you made it this far, good for you.

But there are still a few odd details you may wonder about, like OSHA's requirement for 100 fit factor for half-face, 500 for full face. What's up with that? And what about the fit factors for qualitative fit tests?

OSHA assumes that if you pass a qualitative fit test, your fit factor is at least 100, and vice versa. Is it true? Well, you'll need to read the previous post to find out, but spoiler: maybe not. OSHA is fine with you making this assumption, so make of that as you will.

OSHA also wants you to have mask leakage of <1% due to face seal leakage, or a fit factor of 100 or more, regardless of if you wear an N95 or better. Only filter penetration should be 5% or less. Hence why (some) organizations spent boatloads of cash for TSI N95-Companions, an accessory for the PortaCount CPC machine.

But if you buy a decent N95 mask, it'll probably already have a fit factor well in excess of 100, making the TSI N95-Companion completely unnecessary. All a mask company is really demonstrating when a mask only passes on an TSI N95-Companion is that cheaped out on the filter.

What about CNP machines?

CNP machines only estimate aerosol fit factor, and for CNP fit factor, they use a different formula, which we won't cover here.

Edit: Complete List of Exercises Here

Also: @ghhughes@zeroes.ca released a video covering the QLFT procedure for Bitrex and saccharin: https://www.youtube.com/watch?v=-UEKtJRI4pk

This one's a long one. I hope I've caught most mistakes and inconsistencies, but I didn't really plan this out, since I didn't expect it to be this long, so for the sake of correctness, I implore you to look up more established documentation, like... the PortaCount manual.

(Which, unlike this thread, is actually written for the general public, and not just a way to preserve information for myself for later use.)

With that said, a substantial amount of information here was stuck on Twitter and chat rooms for quite a while before I had the motivation to write it down here, so maybe you ought to DM me (@fediversefittester@fedia.social) if you notice a mistake, need clarification, or just want to join a community of CPC-havers on Matrix.

Okay, back on topic:

What's the point of these exercises, anyway?

Did you know: A user seal check does not test an exhalation valve or unseen respirator failures?

These unseen respirator failures are usually due to movement, most of the time. Or... maybe it's the wrong size. Or maybe you just wore it too long. And you know, when you do a user seal check, aren't you technically supporting the mask, and artificially making it better at doing mask stuff?

Lots of questions here, none of which should matter if you do a proper fit test.

(Either your mask works or it doesn't. No reason to overthink it.)

It might be obvious for surgical and cloth masks that they suck, since they immediately fail on the PortaCount, but it's less obvious for earloop KN95s, which may not slip until you move your head.

That's why fit test protocols exist. And why fit testing takes a considerable amount of time, be it electronic or via smelly aerosols.

But if you've been browsing this magazine, and can't afford a PortaCount, don't worry, we'll also cover qualitative fit tests, (a.k.a. the smelly ones, not involving a computer) later on. But keep reading: someday, you might come across a CPC machine, maybe even the OpenCPC currently being developed by OpenAeros.

Since you're on /m/CPCSupport, let's cover the protocols for CPCs first:

If you plan on submitting your personal respirator (used non-occupationally, regardless of type) fit test results somewhere, the current consensus protocols on the socials are modified OSHA(*), Crash-2.5 and Crash-UM. The timings below are published for consistency, should you decide to submit results to some forum.

Again, this is all really only a way to become an informed customer on respirators you can wear during an ongoing pandemic, and which legally does not require respirator usage. So don't use this guide for asbestos mitigation work or something. We are glossing over many other protocols required OH&S bodies in other countries, so, if you plan on using your respirator for work purposes, please refer to your OH&S body for guidance.

Also we're not going to cover CNP machines in this thread, since they don't work with N95s.

(If you don't know what CNP is, it's basically any portable fit testing machine that's not a PortaCount or AccuFit 9000, which is probably not you.)

So with all that said, let's go over the agreed upon protocols for disposable respirators:

*Modified OSHA

TSI has a helpful guide on the actual, classic OSHA compliant fit test protocol. Technically, these old guidelines have been superseded in 2019, however for our purposes, we're just going to ignore them.

The OSHA protocols generally call for 8 exercises, each 40 seconds long in terms of mask sampling on a CPC, with each exercise lasting 1 minute total. The exercise actions are:

1. Normal Breathing
2. Deep Breathing
3. Head Side to Side
4. Head Up and Down
5. Talking (use rainbow passage, or count)
6. Grimace
7. Bending
8. Normal Breathing

Normally, OSHA excludes grimace and only makes the exercise last 15 seconds, causing massive headaches for fit testers without computers, as proctors have to recalculate the overall fit factor, and ignore what the PortaCount says, but for modified OSHA, grimace is included as a 1 minute exercise, so no recalculation is necessary. Just take the overall fit factor put out by the PortaCount.

General CPC Settings

For all exercises described in this thread, these are the general timings for a CPC machine:

8020 Actions	Timings
Mask purge	11 sec.
Ambient sample	5 sec.
Ambient purge	4 sec.
Mask sample	40 sec.
Total time per exercise	60 sec.

If you own an 8020M, your timings may be different. Please adjust your timings accordingly.

Calculating the "Overall Fit Factor"

The overall fit factor is basically the harmonic mean of all exercise fit factors. Simple English Wikipedia summarizes it succinctly.

If you have no idea what a "fit factor" is, make sure you read this prerequisite..

(Also, thanks for coming to my magazine! You might want to read the sidebar first, or click this link.)

Crash 2.5

The timings for each exercise are the same as above (40 seconds mask sampling) but replace each exercise action with:

1. Normal Breathing
2. Jaw Rotation
3. Normal Breathing
4. Normal Breathing
5. Jaw Rotation
6. Normal Breathing
7. Normal Breathing
8. Jaw Rotation
9. Normal Breathing
10. Normal Breathing
11. Jaw Rotation
12. Normal Breathing

For each Jaw Rotation, rotate your jaw, slowly, at least 2 times, each exercise action during the protocol.

To add additional exercises to a PortaCount 8020, hold the "No. of Exercises" button, until the number of exercises reaches 12.

Crash UM

This is essentially an abridged version of Crash 2.5:

1. Normal Breathing
2. Talking (use rainbow passage, or count)
3. Normal Breathing
4. Normal Breathing
5. Talking
6. Normal Breathing

N95 Mode CPC Settings

Not relevant for 8020 (original) or 8020M users In N95 mode, particles have to go through a charged particle separator, increasing the amount of tubing required. Given this, if you perform an N95 mode test, these are the timings you should use:

8020 Actions	Timings
Mask purge	15 sec.
Ambient sample	15 sec.
Ambient purge	6 sec.
Mask sample	50 sec.
Total time per exercise	86 sec.

"Redon"

This exercise is borrowed from CNP machines. We said we weren't going to cover CNP protocols, and, well, we aren't, but as an individual exercise, redon can be quite useful for making sure your N95 straps stay intact across multiple wears. We don't have any consensus protocols yet involving Redon, but if you want to add add a redon exercise to your custom CPC exercise protocol, here are some things to be aware of:

• You need to add an excluded exercise, like "grimace" in classic OSHA. Try to make this excluded exercise as long as possible.
• You'll also need to add a standard "normal breathing" exercise immediately afterwards for consistent fit factor measurements.
• To summarize, if the time for a normal exercise is 1 minute, the time for a complete redon exercise will be 2 minutes, spread across 2 exercises involving excluded "redon" and a "normal breathing" measurement.

Qualitative (Smelly) Fit Tests

Oh, where to begin? To start, viruses are massive compared to other harmful substances. They're made of proteins, which are made of organic compounds, which are massive compared to water, let alone individual atoms. That's unlike gases, which are closer in size to water, since they're usually small organic compounds, which as we've established, are smaller than proteins, which in turn, are smaller than viruses.

So you can imagine separating oxygen, nitrogen, and carbon dioxide from other gases requires an enormous amount of power, not unlike the energy requirements of running a desalination plant, so the only practical way to stop gases from going through requires a chemical reaction, like VOCs with activated carbon. Or VOCs and your nose, which is less desirable for obvious reasons.

Last time I checked, electrostatic filtration media doesn't contain activated carbon. So each of these qualitative fit test methods has to be artifically packed into larger particles, to prevent "smelly particles" from making it through the mask, and you smelling it. Because surprise surprise, without an instrument telling you your fit factor, the only way you know you passed a fit test or not is your nervous system. Good luck to you if some of your nerves are disabled by COVID...

And some smells, no matter how minute they become after packing, get detected anyways. Maybe someone is hypersensitive to one Bitrex compound making it through, even if it would have no relevance in the real world. We call these people supertasters, the opposite problem of not being able to smell (or taste) at all. Good luck with consistency!

So with all that said, here are the general procedures for fit testing qualitatively, with some noted hazards and pitfalls:

Bitrex, Banana Oil, or Anything Else That Requires Sense of Smell

Notes:

• You need a nebulizer to pack these smelly compounds into a particle large enough to not pass through N95 electrostatic filtration media.
• You'll need a hood to contain whatever aromatic compound you've chosen.
• Try to finish the fit test quickly, to avoid aromas making it through the mask due to evaporation.

Steps:

1. Without a mask, don the hood.
2. Have someone spray the substance inside the hood. Remember the smell. If you can't smell it, try a different substance.
3. Take off the hood, and air it out.
4. Put on your mask.
5. Follow the fit test procedure outlined below the othe qualitative fit test methods. If you detect a smell, your fit test is a failure.
6. Ventilate before doing another fit test.

Irritant Smoke

Notes:

• DO NOT USE IRRITANT SMOKE NEXT TO A PORTACOUNT.
• Irritant smoke tubes are made to spec by manufacturers, and should automatically produce large enough particles for fit testing. DIYing it ypourself is probably not a good idea, and would probably not be OSHA approved.
• Try to finish the test quickly, or your respiratory system will have a bad time. This irritant smoke, after all, described in the MSDS as a bit of a hazard.
• Do not use a hood. See above.
• Unless your N95 scores at least 100 on a PortaCount in N100 mode, it will likely fail. This is because the N95 spec allows for filter penetration. That does not necessarily mean it runs afoul of any specifications.
• Ignore any smells you detect. Failure is determined through involuntary coughing.
• If you can't feel pain, or have never coughed in your life, then this fit test method is probably not for you.

Steps:

1. Put on your mask. Hope your reflexes work.
2. Have your assistant wear a mask too, to avoid irritant smoke exposure.
3. Have your assistant read the instructions on how to activate the smoke tubes.
4. Once activated, follow the fit test procedure outlined below the other qualitative fit test methods. Have your assistant spray irritant smoke around your mask during exercises. If you audibly cough, even just a little, your fit test is a failure.
5. Ventilate before doing another fit test.

Actual Gas

Hopefully you didn't just skip to this section because you only believe gas can be used for fit testing, only believe your own experiences to be true and didn't actually read the regulation that even your sacred gas mask manufacturer has to follow...

(Yes, NIOSH approves gas masks. If you thought otherwise, you might want to adjust your worldview...)

• This fit test will only work if you have an elastomeric with an vapor cartridge. Don't fall into the misconception that your pink P100 will stop paint fumes.
• You have to sacrifice an expensive vapor cartridge. Those things expire in a few months once you open them, so hopefully you're planning on doing some painting before then. Pretty nonviable unless you have a industrial complex to throw money at...
• In contrast, meltblown charge lasts for years, well past the expiration date.
• It's probably unnecessary, since PortaCount fit factors are highly correlated with gas fit testing. And it's a lot cheaper too!

Thanks to @nukittobesure@bird.makeup for sending me more disposable mask probes for the PortaCount. If you want to buy Nukit far-UVC lights, or just something to support her, the store's at cybernightmarket.com

@CPCSupport@fedia.io

#CPCSupport

Now that we know how to clean the internal lenses, we should be done, right? Our particle counts are up, there's nothing else to worry about except lasers and circuit boards failing? Not so fast.

You know how vacuum cleaners have two filters, a pre-motor filter (or bag) and a HEPA filter? The reason the pre-motor filter exists is because the motor draws dirt into itself as it moves dirt from the floor to your bag or dust cup. And since motors get hot, maybe some of that dirty air is used to cool the motor itself? Wouldn't that destroy the motor? Surely we wouldn't be that wasteful, right? Well surprise: we are.

(If you've ever forgotten to put back the pre-motor filter or bag in a vacuum cleaner and it sounded funny, that's the sound of a vacuum cleaner's motor being destroyed.)

There are bypass motors, but that requires a separate air stream, making it impractical but for central vacs or other heavy duty equipment.

Now have a look at the PortaCount pump schematic, as described in the manual. Do you see a separate air stream for the pump?

So it's a standard pump that only takes in dirty air for everything. Great. And if you follow the tubing inside the PortaCount, you are lead to the internal inline filter (sometimes called the internal zero check filter) before it leaves the PortaCount to the left of the two ports you plug your tubing into:

And here are the two bottom pre-pump filters:

Of course, TSI says you can ignore these filters, but that's inadvisable, because, for one, TSI doesn't service 8020s anymore, and for another, based on what we know about vacuums now, it would probably be a bad idea. We want to extend the lives of the PortaCounts we have access to now, since new CPCs are shockingly expensive. And even if we could find replacement pumps, getting to it would entail disassembling the PortaCount. Not exactly fun, while also knowing how rare these things are...

So, now that we've established these filters may be important, how do we know when to change them?

Signs you may need to change the three PortaCount filters...

("May" because this is anecdotal as opposed to empirical. While I can't prove you need to change your filters, you wouldn't want to damage your PortaCount now, right?)

The easiest way to know when to change the filters (and probably what TSI does, I guess) is to disconnect the inline filter at the back and do a fit test with another PortaCount to verify a fit factor above 50,000. However, that's a bit of a hassle, you need another PortaCount, and there's always the chance that somebody swapped the low-hanging filters making the PortaCount appear less used than it actually is. (Yikes. We'll get back to that later.)

So instead, here's a checklist you can follow to take a guess as to whether you may need to change your three filters (bottom two and back inline), mostly involving excess age, some obvious, some unexpected:

• First: Check the printed dates! Try finding the calibration date, or, if it's not visible, the manufacturing date. An older date ≈ more usage ≈ change the filters.
• Another sign you may need to change your filters is it takes over 15 minutes to get to 1000 particles/cc. It's a sign your 'internal lenses' are dirty, == excess age.
• If you've cleaned the sampling cone and got higher particle counts, you should probably change the filters ASAP.
• If you got a bunch of dead zero-check filters with your PortaCount. It's either a sign of excessive fit testing, since isopropanol is not friendly to these types, or someone swapped your internal inline filter and didn't tell you. (Yikes, again.)
• You've never been able to reach over 500,000 FF with a candle. It should be relatively easy to reach this number with a candle, due to the amount of particles put out by it. And if the PortaCount has had few hours put since its last calibration date, you should be able to reach 999,000 FF too. Not reaching at least 500,000 could be a sign of heavy use.
• The "Service" message pops up on a non-humid day. Could be a sign of anything really (probably excess age with dirty filters, so avoid treating it like a check engine light).
• Look at the screws of the bottom two filters. In the last few years 8020s were serviced, TSI swapped from 3/32 hex bits to flat head screws for securing the filter covers. If you see hex bits, well, you know what that may mean.
• PortaCounts with dirty pumps are annoyingly loud. If your PortaCount sounds like an air purifier at medium-high power, that's probably bad news for your PortaCount pump, but at least you can start minimizing the damage.

Open the bottom two filters. Again, 3/32" hex or flat head. The filters should not crumble in your hand and you should not see any debris in the filter cup. If you do, well, at least you know you may need to change the filters.

(Please don't leave debris in the PortaCount.)

Obtaining and Checking Filters.

Here's the good news: You can use basically any moderately effective 1/8" tube filter for the back inline filter. Most zero check filters designed for CPCs or zero checking come with an adapter for 1/8" to 1/4" OD barb tubing, allowing you to hook up any inline filter the PortaCount uses, be it for zero-checking or for post-pump filtering.

Of course it's not the most critical filter since it comes after the pump, but I prefer changing it anyway simply because it prevents dust near the exhaust port flowing back to the pump when the PortaCount is off.

• You can get a second zero check filter from ETA Filters, which include the 1/8" to 1/4" OD adapter, and can be used for daily check zero counting, maxing out the PortaCount and giving a perfect fit of 999,000.
• Or, if you've already got a zero-check filter, and its adapter, you can get decently adequate 02FA06A filters from Grainger, or aftermarket ones from vendors like Fluitek, for $10-15 cheaper. These filters will only reach into the 50,000-150,000 range for fit factors maximum, but that should be more than adequate for keeping dust from flowing back into the pump.

If you're going to take out the 1/8"-1/4" OD adapter to check the internal inline filter, you do so at your own risk. Make sure you don't get any dust in the adapter; any significant air bubbles could impact your zero filter's ability to act as a zero check. And no, duct tape is not an adequate alternative.

As you can see, these filters are pretty accessible, which is why they might have been changed on your PortaCount, screwing with your ability to properly rate the age of your filters, especially the bottom two filters, because yikes:

The bad news: The bottom two filters are waaay more obscure. The dimensions are quite odd: 1/2" inner diameter, 7/8" outer diameter, and 1" height.

Personally, I only managed to find a filter with a 1/2" inner diameter, 13/16" outer diameter, and 1 1/8" height. Although this filter was slightly off dimensions wise, it still managed to work in my PortaCount. Unfortunately, there are only a handful of these filters available on the new old stock market, which is why I won't be telling you what these filters are. If you need any, you can either DM me (@fediversefittester@fedia.social). You likely won't be able find them on Grainger, or even the aftermarket manufacturers like Fluitek, not unless there's a massive demand of filters for rare, PortaCount 8020s. Lucky you if you manage to find a new filter that's exactly 7/8" wide and 1" tall. I only stumbled across some slightly imperfect filters by sheer luck.

(And good luck having a filter supply when public health officials ignore the fact there's still a pandemic going on...)

So check your filters everyone. Don't turn your PortaCount (or vacuum cleaner, lol) into e-waste prematurely by neglecting your filters.

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Don't want to create a Lemmy/Mbin Account? Post via the microblog section. You can try and add the hashtags this magazine follows, but here's a better way to get noticed:

1. Mention @CPCSupport

That's it! Your post will get put in the queue for moderation, and we'll be sure to create a link to your post in the 'Threads' section. But if that's not enough:

2. DM @fediversefittester. (fedia.social).

No need to DM @fediversefittester (fedia.io), since I'm a mod, I've probably received your message.

3. (Optional). Add hashtags. But as implied earlier, this isn't as reliable as one might think.

So be sure to mention: @CPCSupport #cpcsupport #cpcsupport

The over-engineered ultrasonic dehumidifier that TSI calls the 8026 Particle Generator was originally designed for the PortaCount 8020A, so you didn't have to have open flame candle, if you were, I don't know, paranoid about the flammability of reagent isopropanol (or some other substance in the room) and didn't trust yourself to not cause mayhem. Instead, you put a salt tablet (of weight specified by TSI) into the cup, added water, turned it on, and... salt particles to the rescue!

(along with all the other minerals in the water... ouch)

But you paid good money for this (overpriced) humidifier...

(or you got it with the N95-Companion due to its excessive, useless filtration)

...so surely there must be another use, right? Well, according to the manual on page 6, yes...?

Alternate Uses for the Particle Generator

The Model 8026 Particle Generator may be used as a generalized source of poly-disperse particles in an environment.

I say 'scientific,' but I can't think of any other uses outside of scientific applications for a salty dehumidifier...

Well, in any case, if you had that idea, you might want to slow down a little, because @ghhughes@zeroes.ca found something odd about the weight of the little scientific(?) salt tablets...

Once again, because Nitter is having issues these days, I've created another place for discussion about this issue. But if you want to view this on Nitter: Archive.org link

The thread is copied below again, with higher quality images:

---

TSIIncorporated is the leading maker of mask fit testing machines, and they make a salt water particle generator to use with them. But I can't figure out how much salt to use because the manuals say 100mg tablets, but the tablets TSI supplies are 1g each. 😕

Which is right?

Can anyone at TSIIncorporated clear this up?

The difference is 10x, and I don't know how much effect that will have on particle generation.🤔

The 8026 particle generator has been used in many published studies, but now I wonder which salt concentration was used?

The 2015-2022 manuals and the TSI product page for the salt tablets says they are 100mg. But I've only ever seen the 1 gram tablets that came with my PortaCounts.

Link

Has anyone else weighed their TSI salt tablets?

Note from the listing that TSI sells 100 of the tablets for $55.

If they really are 100mg each, that's 10 grams of salt at $5.50 per gram. 🤔

The 8026 generator is also expensive, sold at institutional pricing, ~ $1,343.71 new. 😬 (Sometimes there are used eBay bargains.)

It has been a staple of mask fit testing and published studies for decades. So I'm kind of surprised I can't find answers to this easily on line.

---

End of thread. So, two possibilities, IMO, here:

Either TSI made a calculation error (100 mg == 1 g?). Personally, I think this is unlikely due to the fact that salt tablet weight seems to only be rounded to 2 sig-figs max.

Or, the N95-Companion demanded more salt particles, salt tablets crumbled, etc, and TSI was forced to add more salt (without letting anyone know?) As I can attest...

(but don't quote me on that, unless you have an N95-Companion yourself.)

In any case, hopefully you (and no scientist, yikes) have (or has) blindly trusted TSI to weigh their salt tablets correctly.