Thread: Warnings and Other Information on Dust Masks

Originally Posted by Chris Parks

If a mask has a tight seal, it has be be able to have air pass through it at that rapid a rate. That's not easy. The more substantial the filtration, the more the resistance to flow, and the harder that becomes.

This is the problem I've had with the disposable masks that don't have an outflow valve. When you exert yourself, as you do when hand-sanding for example, you breath out a lot of moisture, which restricts the airflow. They quickly become useless. For woodworking, I think you need the masks with an outflow valve to expel the moisture.

Here is where "said resident anaesthetist" (Bernmc) says about breathing flow rates
Testing out the Triton Full face respirator

On reflection I think this thread should have gone into General WW.

I've worn N95 masks quite a bit, sometimes grinding metal, but exhausting the air is a lot smarter (the smoke and fines still stick to your eyes, and you can feel that the next day).

I guarantee I've never had one totally seal, but the ones you mention (the real ones at home depot) have strong elastic and they're close. Close enough that I don't have a black trail coming in.

Even the cheap KN95 masks marked as n95 are a drastic improvement when metal grinding - but again, exhausting the air out of the shop high volume low velocity and creating a directional bias is far far superior. It would be with woodworking, too, though I don't do that much sanding and only resawing by hand puts a lot of dust in the air that I can see (but it does do that and you can get an accumulation in mucus).

when we found out early on that the only masks that really stopped covid were N95s and they had to be fitted, I knew nobody was going to wear them. I think, in my opinion at least, the whole social distancing in doors with masks probably cost lives because people had a false sense of security, and the cloth masks were almost pointless, but hey, I guess you gotta get everyone on board.

At any rate, we gave my mother in law an N95 mask because she's already a germaphobe and she took it off in less than a minute. I've used valveless masks on tight before to do insulation, which is a miserable job, but you take your lumps when you do a job like that and suck it up.

Once I got one of those partial face rubber seal organic vapor respirators, wearing the disposables and trying to get them to seal in the same class was a lost cause. It's too much fiddling. you can tell instantly with the rubber seal masks if they're sealed. just fart.

Kidding, thought that does work, too - find something that has any strong aroma and breathe it in - if you can smell it, either it's not sealing or the OV canisters need replacing.

the whole dust control thing wasn't really a big factor in me going to woodworking almost entirely by hand, but it had a lot to do with it. I would challenge anyone who does good point collection and who can crack a window to find any change in mortality or morbidity due to woodworking. I knew toymakers when I was a kid (parents were in a craft circuit) who would develop sensitivities to dust because toymakers have to hustle to make any money (high volume, low margin) and none of them ever had issues outside of sensitivities, and I don't remember any who died early or who had anything that came close to resembling a late 60s or early 70s heavy smoker.

Totally different conversation if it's someone working an hourly job or having to be in the shop to make a living, but I think of the whole dust collection thing (instead of masking) about the same as the amish think about us in the states when it's 83 degrees out and we have the air conditioner roaring away.

I am in the heath industry so have worn a lot of N95 masks last few years. There are a lot of masks with P2/N95 material but only 2 disposable masks have consistently passed fit testing most people:

Access Denied

3M also make this mask for non health care setting - it is with blue straps and doesnt have the 'fluid resistance' which is 'ASTM level 3' surgical mask

TRIDENT(R) P2 Level 3 Surgical Disposable Respirator – Trident Safety

It seems like most other designs do not consistently and reliably seal the face

But when woodworking, when you can have have valves, why bother with disposable masks? Get a silicon respirator with inlet and exhaust valve or PAPR. Much more comfortable long term.

With silicon respirator, you can take off the filters and cover the inlet valves with your hands to test fit, if you cant breath in then its sealed

edit:
If you want a disposable mask with exhaust valve, this one is a similar to the one which has passed fit test for many HCW (basically same design except it has a valve and doesnt have the fluid resistance certification required for health care setting)
Access Denied

Originally Posted by qwertyu

With silicon respirator, you can take off the filters and cover the inlet valves with your hands to test fit, if you cant breath in then its sealed

Ditto - I should've probably added my mother was also a crafter (I did add that), but she sentenced my dad to prepping all of the wood she needed to paint kitsch. Being thrifty, and having a "real basement" rather than a third under house furnished floor, he attached plastic around 1/4th of the basement got two sanders and a band saw. And proceeded to make choking amounts of dusts - three dimensional amounts laying on things.

It took him little time to realize he wanted to get a (I call it rubber, but you're probably right - it's silicon) a single valve single filter dust respirator. He would come upstairs looking like he stood in the snow with a "skin colored" clean area where the mask was.

My parents can be notoriously stingy - the mask cost about $22 or something at the time in the 1980s and I remember hearing endless complaining about the cost of it, but it did its job.

Too, when you get a valved N95 mask, aside from them really not working well for more than a few light uses, they stink almost right away. It takes little time for them to become more expensive and while all of them will leave pretty convincing marks on your face if worn for a long time, the "tight enough" single use masks will leave marks that last longer than getting showed to go out to dinner.

There are a few difference between using a well fitting mask used by woodworker versus in a medical situation.

Apart from perhaps triggering woodcut allergies, for most woodworking DIYers, occasional exposures (even high amounts) to wood dust is very unlikely to cause any immediate or even long term problems.
In contrast, in a medical situation a single exposure from a highly infectious whatever can lead to major problems.

The next difference is that many pathogens, like some viruses, don't last long when exposure to air for even short periods.
This means masks may not be necessary to use in a workspace after a certain time period.

However, wood dust never really dies, it breaks down and becomes finer and finer (ie the worst kind) and stays in a shed until physically removed.
This means once wood dust is generated in an unventilated workspace a mask should be worn until that dust is cleaned up.

Likewise with clothing. In medical situations face shields, disposable garment, head and foot coverings are often used.
Woodies using only masks (ie no extraction) end up covering themselves and their sheds with a layer of fine dust that they carry around with them indefinitely. The body being warm acts like an external chimney and generates warm air currents that start at the feet and rise upwards carrying fine dust past breathing orifices.
In repeated heavy dust generating situations mask should be left on until clothing is removed outside a workstation right up until the woodie takes a shower.

Combine all of the above with ill fitting masks is why extraction and ventilation are where possible to use far better options.

our work place recently got us "fit tested".

most of us with facial hair failed. they actually pump salt into the air and measure how much is being transfered into the inside of the mask while you walk, bend and look in certain positions. 95% of the people with facial hair failed as you just cant get a decent seal on your face.

I'm pretty prior to COVID the government or worksafe was having a large push on "fit testing" as I think they've realised that there is a bit more to mask wearing then just holding a mask against your face with your hands while you awkwardly perform a task with the other.


the masks we've been given for use are a battery operated half face model.

According to my son, who works in medical mask research and development, fit and comfort are the two big challenges. Evidently, there is are many facial mobility types and no one mask design is going to fit all and certainly not comfortably. The holy grail is customised masks that are tailored to the individual, which I expect wouldn't be cheap. Perhaps an option in medical settings like operating theatres and infectious diseases wards, but unlikely to be affordable any time soon in our sheds.

On beards, that son has a Gandalf length beard that he has to plait to get inside a mask when he is in the operating theatre. I'm yet to try that myself...