HEPA Air purifier(s) for fine dust

[onionlikeapple]

Hi all.

I’m getting far enough into the hobby where I’m finding myself more and more concerned about dust collection.

I have a shop vac with a cyclone attached which I use to attempt to get most dust at source. However there is still a fine layer of dust across most things in the garage.

The garage also doubles as a home gym, so want to it to be as safe as possible for whoever in the house might be using the gym after my doing whatever in the workshop. It’s roughly 21m squared in size, and I use the workshop in a hobbyist capacity.

I’ve seen the Record Power air filter box which I’m tempted by. However, we have a couple of the HEPA air purifiers at home that don’t get a huge amount of use. How close would those air purifiers get to matching the RP solution? I would get the RP, and will do if it’s necessary, I’m just becoming increasingly aware how much everything is costing me.

Not sure if its worth mentioning, but its 2 of these Philips air purifiers.

And as an secondary question, if I’ve been sanding in the garage, how long do you reckon it would be until it’s safe for someone to use the gym, providing all the above accommodations are in place eg shop vac, air filter of sorts? Appreciate that’s hard to put an exact number on.

Thanks!

 

[Inspector]

To answer the secondary question. There are lots of inexpensive particle counters that you can use to measure the outside air quality to get a baseline and then monitor the air in the garage for each activity. That will tell you when you need to put on PPE and when the levels are low enough to remove it. Just don't put the counter directly in the dust making stream like at the end of a stationary belt sander. It will overwhelm it and clog it up.

Pete

 

[onionlikeapple]

To answer the secondary question. There are lots of inexpensive particle counters that you can use to measure the outside air quality to get a baseline and then monitor the air in the garage for each activity. That will tell you when you need to put on PPE and when the levels are low enough to remove it. Just don't put the counter directly in the dust making stream like at the end of a stationary belt sander. It will overwhelm it and clog it up.

Pete

Thanks for this Pete. I've just had a look on Amazon and the like, and the cheapest counter I'm seeing is ~£90. Was that the sort of ballpark price you were thinking of with the particle counters?

 

[Inspector]

They seem to be cheaper here, in the $50Cad range in some instances. https://www.amazon.ca/VEVOR-Profess...-4-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

You could try direct from China and pay even less. Temu, Aliexpress, etc. Or get a better one for about what you pay for the Amazon ones.

The object is to know roughly how much dust is in the air so you aren't guessing.

Pete

 

[onionlikeapple]

They seem to be cheaper here, in the $50Cad range in some instances. https://www.amazon.ca/VEVOR-Professional-Formaldehyde-Temperature-Thresholds/dp/B0D5CBQZ91/ref=sr_1_4_sspa?crid=1A18E4XGUVPRR&dib=eyJ2IjoiMSJ9.9qJt8SjSznY5nwer_TXgxcswZNQ5nJPOs5FFdvuPaSSkvF3wz2nwkvRYuRGhWVDNTJbdupKc3iQbLdnlwJ5kfQHB_NEydTh5wOCML1Ca1MUWgCvL2dbEuL5YZWvaLDXH1QCIOsATPb78kjXhrx1X52VfvjHkdC7ylp87AthhDycDVRAcXbDX79DHPGjfAtJgJVHtHk9JLu-8H63clRH3k5pbRn-1fXsEe96cWOuCt0jOtJS3z4BrwNRRWlbdLzyFnx0smsJTes3OUUUO1ICoFYsF27Ta5BGT1IyMweLBwUI.GAl1yMxvPdS7TKnV-TAZ1sIo39r9vmEr1daGLvOvu20&dib_tag=se&keywords=particle+counter&qid=1736355654&sprefix=particle+counter,aps,284&sr=8-4-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

You could try direct from China and pay even less. Temu, Aliexpress, etc. Or get a better one for about what you pay for the Amazon ones.

The object is to know roughly how much dust is in the air so you aren't guessing.

Pete

I'll do some research on what that looks like in the UK price wise.

Our air purifiers have a - somewhat simple - air quality LED on it (red = bad, purple = getting bad, green = good), and I'm wondering if thats good enough for this job too.

 

[onionlikeapple]

Just seen this from IKEA - could be interesting perhaps. And this one for an absolute bargain of £7.99.

 

[SammyQ]

Both of those IKEA hobbies are limited. 2.5micron. The dangerous stuff is sub-micron. IKEA pair can't detect it.

 

[SammyQ]

Both of those IKEA hobbies are limited. 2.5micron. The dangerous stuff is sub-micron. IKEA pair can't detect it.

WHY, OH WHY did Otto Korrwrecktt make j-o-b-b-i-e-s into "hobbies"?? This prim, puritanical, We-think-Billy-Connolly-is-a-blasphemer kind of censorship is:
A) Irritating
B) Unnecessary
C) A contextual idiocy.
D) A sign of a constipated mind.

(Sorry, again in context, that last one just seemed so apt!).

Yet again Folks, we visit the oxymoron known as "Free Speech".

 

[onionlikeapple]

WHY, OH WHY did Otto Korrwrecktt make j-o-b-b-i-e-s into "hobbies"?? This prim, puritanical, We-think-Billy-Connolly-is-a-blasphemer kind of censorship is:
A) Irritating
B) Unnecessary
C) A contextual idiocy.
D) A sign of a constipated mind.

(Sorry, again in context, that last one just seemed so apt!).

Yet again Folks, we visit the oxymoron known as "Free Speech".

…

Yeah so anyways, air purifiers…

 

[Sideways]

The record power air filter that first comes up in a google search is specified as having a 1 micron filter.
That's all.
No reference to an actual standard in the specification on the website. Maybe more if you download the manual, maybe not.

The following definition of HEPA filtration is from Wiki.
It doesn't sound like that Record filter is anywhere near HEPA standard and visually it doesn't look to be.

"Common standards require that a HEPA air filter must remove—from the air that passes through—at least 99.95% (ISO, European Standard)[4][5] or 99.97% (ASME, U.S. DOE)[6][7] of particles whose diameter is equal to 0.3 μm, with the filtration efficiency increasing for particle diameters both less than and greater than 0.3 μm."

Air filtration generally. Aim for 6 to 10 air changes an hour so the air is cleared in about 10 minutes. You would be able to see the air clearing as you watch it.

 

[Chris152]

If you can open the garage door(s)/ windows, it'll clear much more quickly if there's any breeze. Bit chilly at the moment tho.

 

[onionlikeapple]

The record power air filter that first comes up in a google search is specified as having a 1 micron filter.
That's all.
No reference to an actual standard in the specification on the website. Maybe more if you download the manual, maybe not.

The following definition of HEPA filtration is from Wiki.
It doesn't sound like that Record filter is anywhere near HEPA standard and visually it doesn't look to be.

"Common standards require that a HEPA air filter must remove—from the air that passes through—at least 99.95% (ISO, European Standard)[4][5] or 99.97% (ASME, U.S. DOE)[6][7] of particles whose diameter is equal to 0.3 μm, with the filtration efficiency increasing for particle diameters both less than and greater than 0.3 μm."

Air filtration generally. Aim for 6 to 10 air changes an hour so the air is cleared in about 10 minutes. You would be able to see the air clearing as you watch it.

So you'd be more in favour of a HEPA air purifier than the RP system?

 

[onionlikeapple]

If you can open the garage door(s)/ windows, it'll clear much more quickly if there's any breeze. Bit chilly at the moment tho.

This is a two fold thing:

- A couple months ago we got a mouse in the garage and it turns out I am proper Tom and Jerry stand-up-on-a-chair scared of mice. It got in because I left the garage door open whilst tidying.

- Very cold.

So I'm trying to avoid doing that ha. But totally take your point!

 

[Chris West]

Hi all.

I’m getting far enough into the hobby where I’m finding myself more and more concerned about dust collection.

I have a shop vac with a cyclone attached which I use to attempt to get most dust at source. However there is still a fine layer of dust across most things in the garage.

The garage also doubles as a home gym, so want to it to be as safe as possible for whoever in the house might be using the gym after my doing whatever in the workshop. It’s roughly 21m squared in size, and I use the workshop in a hobbyist capacity.

I’ve seen the Record Power air filter box which I’m tempted by. However, we have a couple of the HEPA air purifiers at home that don’t get a huge amount of use. How close would those air purifiers get to matching the RP solution? I would get the RP, and will do if it’s necessary, I’m just becoming increasingly aware how much everything is costing me.

Not sure if its worth mentioning, but its 2 of these Philips air purifiers.

And as an secondary question, if I’ve been sanding in the garage, how long do you reckon it would be until it’s safe for someone to use the gym, providing all the above accommodations are in place eg shop vac, air filter of sorts? Appreciate that’s hard to put an exact number on.

Thanks!

The attached is a lengthy but very useful treatise on this subject. https://www.billpentz.com/woodworking/cyclone/index.php#google_vignette

It is lengthy so to give you a couple of highlights - Shop vacs don't put up enough airflow to get the really fine dust and this is the dust that is most harmful. The human body is actually pretty good about protecting us from particles of 10 microns and above but not smaller. If you have dust laying around the shop, you have a problem. Anytime some walks through they will stir it up and breath it and bear in mind the truly hazardous particles are so small as to be not visible without magnification.

"Unlike blown air that will hold together for a long distance, sucked air comes from all directions at once so air speed drops off at roughly 12 times the distance squared (4*Pi*r*r). So the problem is our powerful dust collection systems suck so airspeed falls off so quickly they cannot collect the fine dust before normal room air currents blow the fine dust all over. The experts found in addition to good hoods that manage the fast moving air streams, we also must surround each tool with a large low pressure area or "bubble" around the working areas of our tools. The air speed inside this bubble must be at least fifty feet per minute out to fifteen and a quarter inches in all directions or normal room air currents will blow the fine dust all over before it can be collected. It takes a lot of air to build a bubble big enough to pull in the fine dust ample to pass EPA air quality tests, right at 1000 cubic feet per minute (CFM) at each small shop stationary tool."

 

[thetyreman]

something like this should do it

https://www.axminstertools.com/axmi...7694?queryID=a5a2fafeaa3a4d80729369e3de353aee

 

[Sideways]

So you'd be more in favour of a HEPA air purifier than the RP system?

My point was to support a previous poster who pointed out that the really harmful dust is the sub 2.5 micron stuff that is light enough to linger in the air for a long time and small enough to be drawn down into the lungs.
There is a lot of info about the sizes of different types of particles on the web and the different grades of filter you need to capture these. Depending on what you work with, pick the filter to suit the particles you are worried about.
The record power and others do take out dust that your typical high volume low pressure dust extractor will happily blow through it's bag, but they are a long way short of HEPA filtration which is a different grade of filtration altogether. You just have to look at the filters to see the difference in quality.

Personally, I have an air filter that is probably comparable with the record but a different design. Useful. High flow so it clears the air fast, but not a HEPA filter.
I consider the high airflow to be important when I do use this device, mostly because my table saw throws a lot of dust and a lot of that escapes the dust extraction. But if I was dealing with dangerous dusts I would be using a true HEPA rated respirator and a HEPA (H class) vacuum cleaner.

 

[Chris West]

The article says that most popular combination dust collector/filter units don't put up enough airflow but even if they do, the filters will return a certain amount of dust back to the shop. If you can, the best solution is to vent the dust outside and use a ducting system to go from tools to the dust extraction unit. If you cannot do this, you need to get a dust collector that will put out approx. 1200 cfm to get the recommended 1000 cfm at each tool. Also, if you cannot vent the dust outside you need a large filter than can handle that flow rate and it will need to be changed regularly, depending on use. You could blow the filter off with compressed air but tiny wood dust particles are sharp and eventually they will tear the filter element.

You are right of focus on this. We have ignored this problem for far too long and we risk lasting damage to our lungs including serious diseases like COPD.

Lastly if you cannot afford this level of dust extraction, wear a good quality mask but recognize the dust is still in your shop and is a hazard as long as it remains there.

 

[Chris West]

My point was to support a previous poster who pointed out that the really harmful dust is the sub 2.5 micron stuff that is light enough to linger in the air for a long time and small enough to be drawn down into the lungs.
There is a lot of info about the sizes of different types of particles on the web and the different grades of filter you need to capture these. Depending on what you work with, pick the filter to suit the particles you are worried about.
The record power and others do take out dust that your typical high volume low pressure dust extractor will happily blow through it's bag, but they are a long way short of HEPA filtration which is a different grade of filtration altogether. You just have to look at the filters to see the difference in quality.

Personally, I have an air filter that is probably comparable with the record but a different design. Useful. High flow so it clears the air fast, but not a HEPA filter.
I consider the high airflow to be important when I do use this device, mostly because my table saw throws a lot of dust and a lot of that escapes the dust extraction. But if I was dealing with dangerous dusts I would be using a true HEPA rated respirator and a HEPA (H class) vacuum cleaner.

These kind of filters are a placebo. Among other shortcomings they tend to create a channel within the overall airspace and only the air within that channel gets filtered. It takes a much higher flow rate than these things put up and the flow needs to be directed frequently around the space to pull the finest particles into the filter from around the entire room.

 

[Chris West]

My point was to support a previous poster who pointed out that the really harmful dust is the sub 2.5 micron stuff that is light enough to linger in the air for a long time and small enough to be drawn down into the lungs.
There is a lot of info about the sizes of different types of particles on the web and the different grades of filter you need to capture these. Depending on what you work with, pick the filter to suit the particles you are worried about.
The record power and others do take out dust that your typical high volume low pressure dust extractor will happily blow through it's bag, but they are a long way short of HEPA filtration which is a different grade of filtration altogether. You just have to look at the filters to see the difference in quality.

Personally, I have an air filter that is probably comparable with the record but a different design. Useful. High flow so it clears the air fast, but not a HEPA filter.
I consider the high airflow to be important when I do use this device, mostly because my table saw throws a lot of dust and a lot of that escapes the dust extraction. But if I was dealing with dangerous dusts I would be using a true HEPA rated respirator and a HEPA (H class) vacuum cleaner.

You are right - the really harmful particles are the very small ones no matter what kind of wood it is. Certainly some wood types produce irritation to a greater extent than others but the real issue comes from the very fine particles regardless of the species. Capturing these takes much higher flow rates, near the point of origin, to keep them away from our lungs.

 

[onionlikeapple]

The article says that most popular combination dust collector/filter units don't put up enough airflow but even if they do, the filters will return a certain amount of dust back to the shop. If you can, the best solution is to vent the dust outside and use a ducting system to go from tools to the dust extraction unit. If you cannot do this, you need to get a dust collector that will put out approx. 1200 cfm to get the recommended 1000 cfm at each tool. Also, if you cannot vent the dust outside you need a large filter than can handle that flow rate and it will need to be changed regularly, depending on use. You could blow the filter off with compressed air but tiny wood dust particles are sharp and eventually they will tear the filter element.

You are right of focus on this. We have ignored this problem for far too long and we risk lasting damage to our lungs including serious diseases like COPD.

Lastly if you cannot afford this level of dust extraction, wear a good quality mask but recognize the dust is still in your shop and is a hazard as long as it remains there.

Thank you for all this info. I've gone over the article but will need to sit down with it to have a proper in depth read.

Based on your summary and what I have read though, I feel like I'm in a tricky place. I wear my respirator with HEPA filters whenever I'm going into the garage to use tools so I feel I'm reasonably well protected in that instance (that - plus shop vac + cyclone at source of tools - even if it is somewhat flawed). However, when using the gym, thats not possible.

Venting outside isn't currently an option, and would require modification to the house to do. I'm not against it, but I'm not far enough into the hobby yet to know whether it's worth the expense to do that or not.

I think I just feel a bit overwhelmed honestly. I'd just like to cut some wood in the garage without this fear that I'm doing irreparable damage to mine or my girlfriends lungs if we go into the garage to also use the gym. Maybe it's just not possible to have a DIY workshop and a gym in the same space.

Or maybe I'm overthinking it as a hobbyist. Its tough not to though because the consequences of ignoring dust collection are fatal.

Apologies, a lot of streams of thought here.