dust collection particle size: how small to go?

[mqbernardo]

OK, thanks for reading and sorry for coming at this again. after some thought on an air filtration system (now settled) and after reading through some of Bill Pentz´s notes i started thinking about my new dust collection system (my old one is just too underpowered).
as you all know (and i´ve just recently discovered) the smaller the dust particles are, the worst offenders they are to your health/lungs membranes, so you should go with the smaller particle size filters you could find/afford on your DC system, right? of course, there are constrains to how small you can go (even if only financial ones) and the filters - if the pore size is small enough and reduce the net area IIRC - will end up stealing some suction from your dust collection and should clog faster (i´m just thinking out loud, please correct me if needed).
so i´m asking for advice on a sensible particle size for a dust collection system. I will connect it to my drum sander unit, which is a small Jet 10-20 and will be using it for the last stages of thicknessing guitar plates (i already talked about that on another thread, sorry for repeating myself), so i won´t be using any MDF, nor will i be making huge amounts of dust (the woods will mainly be spruce and indian rosewood BTW). i´ve seen 0.2 micron filters, but i don´t know if i must go that low. In the beginning i was thinking about the axminster UB-801F which claims 5 microns particle filtration, then i thought about adding the 1 micron canister filter, but then i started hearing that one should use sub-micron filters (which to my knowledge axminster does not have)... this quickly gets very confusing. any help appreciated!

thanks in advance,
Miguel
portugal.

edit: edited for typos.

 

[CHJ]

In a home workshop I think the sensible thing to do is entrap as much airborne dust to as small a size as possible within the readily available and affordable shop filter systems.
Then use personal protection to reduce the exposure to 0.5 µ m and less.

A very complex thing this dust hazard problem

 

[Dangermouse]

The other way to go, at least in the summer is to vent the air / dust to the outside, with a duct bringing fresh air in. Admit this will not work in the winter as the incoming air will be COLD, but at least you would save on filters in the summer, so you could get better ones for the winter with the money you save.

(Preparing to be shot down in flames) #-o

 

[beech1948]

Miguel,

I think research has it that the particle size of wood dust that matters is two fold.

1) Sizes 0.5 micron and larger are caught by the nose on inhaling. Obviously less than pleasant but 0.5 micron can be caught quite easily
2) Sizes from 0.38 micron upto 0.5 micron can be inhaled into the lower chest and lungs

I recall from some old reading that wood particles are 99.6% likely to be above 0.3 microns. So it seems to me that aiming for 0.3 and above is likely to be successful.

If you are anxious about smaller particles then by all means try to capture them. Below 0.3 it becomes a trade off between cost and health.

Sample docs
http://ntp.niehs.nih.gov/ntp/newhomeroc/roc10/wd.pdf

Al

 

[mqbernardo]

Thanks for the kind replies!

I´ll give those links a reading, to the best of my abilities.

I din´t knew my nose hairs trapped dust above 0.5 microns - i guess i´m blessed as i have a lot of hair inside the nose! (yuck!) so i guess the air filtration system (above 1 micron) isn´t as mandatory as i supposed - but it´ll be a good help.

and what about sub 0.3 micron filter/dust collection combos out there? any suggestions? axminster, as said, doesn´t carry any and here in portugal there aren´t any dust collection systems aimed at the home workshop (just industrial ones).

again, any help is much appreciated!

thanks,
Miguel.

 

[Jensmith]

I have a Camvac dust extractor that filters down to 0.4 microns. Think that's the lowest you can get in a dust extractor.

I personally don't fancy relying on my nasal hairs to filter anything as a good proportion of the time you're going to be breathing through your mouth due to exertion and then much more goes down directly into your lungs (as per the linked article).

 

[beech1948]

Miguel,
You said
>>>>>>and what about sub 0.3 micron filter/dust collection combos out there? any suggestions? axminster, as said, doesn´t carry any and here in portugal there aren´t any dust collection systems aimed at the home workshop (just industrial ones).<<<<<

The point I was trying to make but failed to was that 99.6% of all wood particles are larger than 0.3 microns so any filter below 0.3 would be to catch a very very small number of particles.

What you could do is buy a 3M face mask with a P3 or HEPA filter and use this for the dustiest operations.

Al

 

[CHJ]

.....The point I was trying to make but failed to was that 99.6% of all wood particles are larger than 0.3 microns so any filter below 0.3 would be to catch a very very small number of particles.

What you could do is buy a 3M face mask with a P3 or HEPA filter and use this for the dustiest operations.

Al

This was the point of my reply above, trap the bulk of it with 'standard' extractors/collectors and then use personal protection for the lower volume small stuff that's most risk to your lungs.

 

[mqbernardo]

Thanks for the replies, guys. they´re appreciated!

Miguel,
You said
>>>>>>and what about sub 0.3 micron filter/dust collection combos out there? any suggestions? axminster, as said, doesn´t carry any and here in portugal there aren´t any dust collection systems aimed at the home workshop (just industrial ones).<<<<<

The point I was trying to make but failed to was that 99.6% of all wood particles are larger than 0.3 microns so any filter below 0.3 would be to catch a very very small number of particles.

What you could do is buy a 3M face mask with a P3 or HEPA filter and use this for the dustiest operations.l

Ooops... typo alert, i meant 0.5 microns (the ones our nose doesn´t cope with very well and are not in the 0.45%) - but yeah, i´m being a little paranoid here. Although i could´ve added that since i started using the drum sander i´m always with a dripping nose and have numerous headaches. i also have a bad sinus case and all wood dust makes it go crazy, so i´m just trying to cover all the options. So, if by any chance a <0.5 microns system is available at a realistic cost, i might go for it.

This was the point of my reply above, trap the bulk of it with 'standard' extractors/collectors and then use personal protection for the lower volume small stuff that's most risk to your lungs.

That might be an option, although my 3M mask still fails to protect me from the mentioned problems - and i do not make a lot of dust...
I guess the problem is with the particles that stay airborne - i´d have to use a mask at all times, since my air filter would only go down to one micron... or am i over-thinking and over-complicating this stuff? anyway, i appreciate your attention to my questions and the time you´ve taken to answer them.

I have a Camvac dust extractor that filters down to 0.4 microns. Think that's the lowest you can get in a dust extractor.

I personally don't fancy relying on my nasal hairs to filter anything as a good proportion of the time you're going to be breathing through your mouth due to exertion and then much more goes down directly into your lungs (as per the linked article).

That´s a good point. Thanks!

cheers,
miguel.

 

[beech1948]

Miguel,

Check your 3M mask and see what type of filter it uses. Most come supplied with a P2 filter but would be better for you with a P3 filter ( if you need to know the difference then look up the International Standards). A p3 will take out particles down to below 0.2 I think but you will experience a small increase in resistance to breathing in.

What 3M face mask do you have

Al

 

[CHJ]

......I guess the problem is with the particles that stay airborne - i´d have to use a mask at all times, since my air filter would only go down to one micron... or am i over-thinking and over-complicating this stuff? anyway, .....

I'm afraid that wearing a full positive airflow face shield and mask AT ALL TIMES whilst in the shop is the only answer. A high proportion of the offending dust stays airborne much longer than you might realise. And even when you are not actually producing it you will be stirring it up off any surface it has settled on previously.

Remember that your clothing will also be contaminated, therefore you can transfer it to your face or breath in the disturbed dust after you leave the shop.

When you are next in the workshop place a polished piece of metal or a mirror flat on a shelf or other convenient place and check it the next day by drawing your finger across the surface.

Also with any face mask, it does not matter how good the filter is if you are drawing air past the mask edges, this is where a positive flow mask scores.

 

[mqbernardo]

Miguel,

Check your 3M mask and see what type of filter it uses. Most come supplied with a P2 filter but would be better for you with a P3 filter ( if you need to know the difference then look up the International Standards). A p3 will take out particles down to below 0.2 I think but you will experience a small increase in resistance to breathing in.

What 3M face mask do you have

Al

i have these masks :
3M 4252
vitrex twin filter

I'm afraid that wearing a full positive airflow face shield and mask AT ALL TIMES whilst in the shop is the only answer. A high proportion of the offending dust stays airborne much longer than you might realise. And even when you are not actually producing it you will be stirring it up off any surface it has settled on previously.

Remember that your clothing will also be contaminated, therefore you can transfer it to your face or breath in the disturbed dust after you leave the shop.

When you are next in the workshop place a polished piece of metal or a mirror flat on a shelf or other convenient place and check it the next day by drawing your finger across the surface.

Also with any face mask, it does not matter how good the filter is if you are drawing air past the mask edges, this is where a positive flow mask scores.

i don´t need to put a mirror there, i see the dust everywhere... it´s driving me insane.

once more, thanks for your input. may i ask what dust collection system you guys currently use?

cheers,
miguel.

 

[CHJ]

.....may i ask what dust collection system you guys currently use?

I personally use an older model 3M system, which is no longer marketed.
Chip and dust extraction is a high volume extraction to an outside collector fitted with coarse filtration to maximise air flow.
I also have an external facing 230mm wall extractor fan dumping shop air outside.

Richard Findley uses a more modern Jetstream System

 

[mqbernardo]

Thanks!