Making sense of half face respirators - a useful PDF

BIG CAVEAT: I am far from an expert on this subject, and have asked BobL to cast his eye over this, as he seems to have a pretty good handle on these things.
Anyone else who has good/expert info - please also respond.


I've been wading through too many websites on respirators for a while now. I'm trying to chase down the right combination, but the dilemma has been
a) terminology
b) a profound lack of info by the sellers
c) a chart that says "this goes with that"

Maybe I'm a little slow on the uptake, but I have found it pretty tough going - mainly due to the lack of info and the assumptions that are made. Finally, this arvo, I found a brochure from 3M that goes a fair way to explaining it all. See the attached PDF. (page 9 is the nitty gritty)

To help out those who may be as confused as I have been, for a half-face mask there are usually either 2 or 3 components (despite how they may be photographed):
1. the actual mask, which is useless without either a cartridge or a filter, or possibly both
2. The cartridge - this is the gas filter (not particulates). The cartridge should be replaced when you can start to smell what you are trying to filter out, or at the most after 6 months.
3. The filter pad for particulates (P1, P2 or P3). The filter pad should be replaced when it becomes harder to get air through it.

NOTE that 3M says that P3 filtering can only be achieved with a full-face mask.

In some cases the cartridge and filter are combined, and this is usually only for nuisance level gases - probably what we might get from various finishes etc. Examples of that (I think) would be 3M 2000 series filters. These filters would appear to be in the medium price range. I imagine that this 2000 series wouldn't last as long due to having smaller surface area and carbon filters.

What I have been looking for is a mask/cartridge/filter combination that will cover dust from timber and ash (fireplace), and at least some of the solvents that I use with finishes which might include meths, mineral turps, gum turps, white spirits. I rarely use acetone or thinners.

Up to now I have been using one of the disposable 4151 masks which are A1P2 (A1 gas, P2 particulate), which seem to last for about 6 months or so. After a year the rubber starts to break down and go sticky. I have found them very good, but a little expensive at $40-50 a pop. These have proven to be cat fart proof, and household strength 2% Ammonia proof.

So I think that means I need:
7502 Mask (the last digit represents the size). 6000 series half-face is only so you can leave your helmet/visor on to take off the mask frequently.
6051 (A1) or 6055 (A2) cartridge filter. They don't really explain the diff between A1 and A2, but I assume A2 is a higher level of protection.
5925 P2 Particulate filter with a 501 holder to keep it on.
OR
7502 mask
2128 round filter, but I suspect that these will wind up being more expensive because they will be dust contaminated before the gas part is used up.

Of course your requirements for cartridges may vary, depending on what you are working with. Filter pads for woodwork should be a standard P2, so not much variation there.

IMPORTANT NOTE: when purchasing "cheap" cartridge supplies beware of short expiry dates, or even out-of-date products. Always send them a msg to ask what the expiry date is - you should never purchase a cartridge that is <6 months from expiring from when you intend to start using it. 3M also says this applies to particulate filters, but frankly I find that hard to believe.

Got the deckchair and "refreshments" ready - watching with interest

Thanks for posting that document FF and for taking the time to distill the basics for those that don't have the time or inclination to read it through.

I'm not sure what specific aspects of this you want me to comment on and maybe I'm not the best person to ask about masks anyway because I don't like wearing masks and generally have a low opinion about how they are used and how ineffective they can be. In my former work place where we worked with some incredibly noxious stuff the only time I recall using masks was when we painted laboratories with two pack epoxy and wore full face air wash masks powered by a clean external air supply. Best practice OHS requires masks only be used after all the other possible solution have been utilised so if you work often with particulates and solvents you should really set up appropriate extraction and ventilation to eliminate these so that the use of a mask is unnecessary especially in a confined space like most DITY sheds. Despite this I recognise that there are many situations like emergencies, working on a remote site or inside a broom cupboard where extraction and ventilation are just not practical and then a mask makes sense.

I can appreciate that both users and manufacturers find it difficult to assess when a filter is no longer providing enough air. The Triton Full face powered air mask uses P2 cartridges and comes with a simple little pingpong ball inside an acrylic tube that is screwed onto the fan unit exit and if the pingpong ball reaches the top of the tube all is good - if not replace the filters. Unfortunately this is not possible with an unpowered mask but you could take out the cartridges from such a mask and put them into a Triton fan unit if you had one to test it.

The only option for manufacturers of unpowered masks is then to use a "use by date" method which makes less sense for particulate filters but does make sense for chemical filters since the chemical absorbers in the filters could clump or break down. And the other issue that FF has identified is the seals. Maybe over a much longer period the glues used in the particulate filters also break down - I just don't know. More likely the older any filter is the more likely it leaks from accidental puncture. and short of using a particle counter there's n way of knowing its working.

As far as the gas filter cartridges go I am somewhat amused by the "The cartridge should be replaced when you can start to smell what you are trying to filter out" but for less noxious gasses this is not as bad as it sounds. For the more noxious gasses there are plenty of sensors available that will tell you the actual concentrations of the gases in the air and these should be employed rather than ones nose although these sensors are not that cheap.

Other that the above I can't really see any problems with the 3M document - I'd rather they were overly cautious than not and they seem to be taking that line.

Thanks very much for looking at that Bob. :H

It has become a little more under the scope for me because I have been fooling around with various finishes a fair bit lately. I have noticed that sometimes I have had a bit of a headache.

I strongly suspect that the use by date is all bollocks (even for the cartridges), but....

For gas cartridges I was told to breath the fumes of some cheap nasty perfume through the respirator and if you can smell it then ditch the canister. I've not tried this as no longer have teenage daughter and am unwilling to get caught in the local super buying some.
To extend the life of the gas cartridge I remove it from the face mask after use, let it dry if there is any moisture on it and then seal it in an airtight container.

Tony

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Originally Posted by tony_A

For gas cartridges I was told to breath the fumes of some cheap nasty perfume through the respirator and if you can smell it then ditch the canister.

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That's not something I would recommend or rely on especially for inorganic gasses.

Quote:

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I've not tried this as no longer have teenage daughter and am unwilling to get caught in the local super buying some.
To extend the life of the gas cartridge I remove it from the face mask after use, let it dry if there is any moisture on it and then seal it in an airtight container.

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Not sure that does much but it probably better than nothing,

Hi Brett
just some thoughts

If your shed is clean enough to be playing with finishes, you probably don't need a particulate filter on your mask.
Likewise, if the finish has dried enough that making dust won't stuff it up, then you probably don't need a chemical filter.

If you are noticing head aches after using certain finishes, then perhaps your best option is to improve the ventilation in your shed.

and if the chemical filter is fir spraying, then a whole other lot of considerations came into play.

Quote:

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Originally Posted by ian

If your shed is clean enough to be playing with finishes, you probably don't need a particulate filter on your mask.
Likewise, if the finish has dried enough that making dust won't stuff it up, then you probably don't need a chemical filter.

If you are noticing head aches after using certain finishes, then perhaps your best option is to improve the ventilation in your shed.

and if the chemical filter is fir spraying, then a whole other lot of considerations came into play.

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The particulate filter is more for some tasks that happen outside the shed, but I do use it in the shed sometimes, and then vacate for a while if possible. Not ideal, but...

The headache came when I was applying the finishes on a cold day and had the heater on and the door closed. Again, far from ideal but it was too cold to apply finish otherwise. I vacated as soon as i was finished. Normally I have the door open, which is adjacent to the bench, so ventilation is not too bad (no cross draught apart from fans though).

Having slogged through all those websites to find the right combo.....
....and then sourced them.....

.....I'm better off with the disposable ones I'm using! :doh:

:doh:
:doh:
:club:
Cheapest 7502 half face mask I've found is paintaccess.com.au for $42 plus $15 delivery. If they also sold the correct other bits then delivery would be free, but no.
Then I need a pair of 501 filter pad retainers for $6.45
so that's $63.45 to set it up.

Then I need the P2 filter pads, and the cheapest way to buy them is in a 10 pack from eweld for $101.32 because that makes them $10 a pair for each 6 monthly change (could be sooner though). Otherwise buying them in pairs is about $16 per pair plus delivery.

Then I need 6051 Cartridges, also from eweld, at $21.90 a pair, every 6 months (although I reckon I can stretch that to 12 no worries).

AT least eweld have Click n Collect at Big W so no delivery costs.

So best case scenario is
initial outlay for mask & retainers $63.45
every 12 months (at best) 2x pairs of P2 filters $20, 1x pair of 6051 cartridges $22

3M 7502 mask minimum cost in first year $105.45 (but an additional 8 pairs P2 pads has $80 tied up)
and that gives me protection level A1P2. Ongoing costs of $42 per year minimum.

Now I have just discovered that eweld sell the 3M 4000 disposable mask for $34. This is the mask that I use which gives me A1P2 protection. That is significantly cheaper than I have been paying.

So that same $105 gives me 18 months worth of disposable masks, without having another $80 tied up. AND I don't have bloody great filters hanging off the side of the thing, waiting to catch on stuff......

Even cheaper here at $23 plus post.

I have also discovered why the Carbatec version was so expensive at $64 - it is the top of the wazza overkill 4279 which provides A1B1E1K1P2 which is hardly necessary for most shed purposes (acid gas and ammonia protection).


:charley:
So, ahhhh, thanks for your attention and input.....I'll just go back under my rock now.....:bricks:

Be aware that dust masks, half face, and full face units offer different levels of protection... It's more than just convenience. A full face can easily offer well over 1,000x the protection vs a dust mask...

The one you need generally depends on the exposure level (how bad is the environment) and how long you will be using it. Generally an Industrial Hygenist would do appropriate air testing to determine the correct unit. So for example - a dust mask "filter" may be OK if you don't see more than an hour of exposure every few months. But it is not sufficient if you have to work in it for any significant length of time... It's better than nothing though..

My own experience is also that filters don't last nearly that long. They work way better when new and their effectiveness drops off after you use them and then try to store them... My experience is that they drop way off after a couple weeks...

The most effective thing to do is like Bob said - control the environment as much as possible rather than relying a filter to protect you from nasties.....

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Originally Posted by truckjohn

Be aware that dust masks, half face, and full face units offer different levels of protection... It's more than just convenience. A full face can easily offer well over 1,000x the protection vs a dust mask...

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There are also full face mask and FULL FACE masks. Some full face masks cover just the eyes/nose/mouth while others cover the whole head. Then there are those with forced air so they operate on positive pressure versus those that rely on the user creating the required pressure to suck air through filters (negative pressure).

In general a full head mask with positive air pressure are the safest and require the least amount of care and training to use. They are also the most comfortable for long terms use and provide better protection for folks with facial hair. The Triton full head mask is one such unit and. I find the pump produces sufficient air flow on the unit I have is adequate for light to moderate activity use but it just does not provide enough air for heavier uses like using a chainsaw in warmer weather. They als make great head protection when tackling wasps nests.

Postive full face pressure masks, even those which only seal the eye/nose/mouth are general better that the negative pressure masks. We had these at work for emergencies only and you had to be trained to use them - I wanted to do the training but persons without facial hair were given priority.

Quote:

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The most effective thing to do is like Bob said - control the environment as much as possible rather than relying a filter to protect you from nasties.....

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Correct - this is standard OHS belt practice.

Bob, you've previously mentioned that you have a particle counter mounted in your shed. Is there something affordable and reliable out there, or is yours an expensive jobbie that you "acquired"?

Looking on ebay I can spend from $140 to many thousands....
https://www.ebay.com.au/sch/i.html?_...unter&_sacat=0

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Originally Posted by FenceFurniture

Bob, you've previously mentioned that you have a particle counter mounted in your shed. Is there something affordable and reliable out there, or is yours an expensive jobbie that you "acquired"?

Looking on ebay I can spend from $140 to many thousands....
https://www.ebay.com.au/sch/i.html?_...unter&_sacat=0

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You don't have to even spend $140 - see below

I have 4 particle counters and I made each one from about $70 worth of parts.
3 of the 4 will data log and 2 of these get loaned out to mens sheds
I detail the developments of these in this thread
https://www.woodworkforums.com/f200/d...r-tech-214381/
The more reliable sensors start at post #17
M&J has also posted his very nice system based on teh same sensor in that same thread

In post #138 of that thread I preview this $57 one from ebay
https://www.ebay.com.au/itm/Househol...kAAOSwevdZ7t4C.
It has no data logging but may still be useful so I have ordered one and will test and report on it as soon as it arrives.
Maybe hold off buying one till I do the review?

Dust measurements are very tricky to perform especially at low levels. It's not like you can point a dust sensor and take take a quick measurement well you can but single or a few results may be meaningless. Accurate measurement require logging data and looking at the humidity levels at the same time as humidity affects the levels. If air flow measurements in ducts require extreme patience and care and long data collection times, then dust measurements require even longer times greater patience and processing. When the then cheapish Dylos meters came out in the US about 10 years ago there was a rush by wood workers to buy them - they had no clue how to use them and I'm sure they made all sorts of ill informed decisions about dust because of this.

Anyway lets see what the cheapie will do. I will put this in the practical FAQ along with some details about dust measurements.

Mine arrived on Wednesday. Neat little unit. Haven’t given it a whirl in the shed yet - just had it sampling the air in the sunroom. It has some connection points that I’m yet to identify so it may????? Be possible to pull some data from it.

Groovy, thanks Bob!

Quote:

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Originally Posted by FenceFurniture

:club:

3M 7502 mask minimum cost in first year $105.45 (but an additional 8 pairs P2 pads has $80 tied up)
and that gives me protection level A1P2. Ongoing costs of $42 per year minimum.

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FF an update/alternative on your research and thanks for a great post. I was after the 3M 7502 as well with the same cartridges you mentioned. PaintAccess has a special with the 7502 plus the 501 cover and filters and cartridges for $55 delivered to Victoria. The cartridges and filters are not the 5925 and 6051 but you can buy a pack of them at Bunnings for $24 which includes a pair of 6051 and two pairs of 5925, which is a year's worth. No need to tie up your money buying 10 pairs.

So in my case that's $79 in the first year and $24 per year after that. I find that quite reasonable for good A1P2 protection.

When I read your figures I was concerned how much this was going to cost me, particularly in the first year, but It was that pack at Bunnings that eased my mind. I hope this helps someone

Just a side issue Brett,
If a person, such as myself has "no sense of smell" after a badly broken face and the "rule of thumb" is smelling what you're wanting to filter;

HOW do you start to smell what you're wanting to filter when you can't?

Add to this COPD [COPD is a long-term disease of the lungs which causes shortness of breath. COPD is an umbrella term for conditions including emphysema, chronic bronchitis and chronic asthma which is irreversible. While there is no cure for COPD, there are things you can do to breathe easier and improve your quality of life particularly if it is identified and managed early.] as a result of the chemicals we used in the RAN in the 1970's without any idea of the usage precautions or long term health effects.

Cheers, crowie

Not sure Peter. I think the only thing you would be able to do is replace the "A" part of the filter at least every 6 months. Or use the masks that I use and replace them every 6 months. It really depends on how much stuff you are using that will fill up the "A" part of the filter. The "P" part of the filter is pretty easy - if you can't breathe in properly through it then it needs replacing.

Following on from an earlier post in this thread I tried some cheap perfume on my organic vapour filter and it not a trace was detectable. Some 2 months later when I went to use the mask there was a very noticeable smell of perfume when breathing through the filter. This reinforces the manufactures comments that volatile fumes can migrate through filters when they are not in use and such filters have a short shelf life once they have been used. Even after light use. If you are using your mask on hazardous volatiles it would pay to read the directions from your own vapour cartridge manufacturer. For us low frequency users it would appear that smaller cartridges changed more frequently would be better than large ones that have higher capacity.


Tony