A preliminary air quality analysis of my shop

[cgallery]

So I don't know if this belongs in Tool Talk or not but it sorta has to do with dust collection and I figured I'd put it here.

Background: My shop is in my basement. I have a Ryobi BT3K, a small Inca (8-5/8" wide but short bed) jointer/planer, Inca 9-1/2" bandsaw, A Ridgid oscillating belt sander, and a router table with downdraft box. I use a Ridgid shop vac with 2-1/2" flex hose network for "dust" collection (along with a separator).

All my tools have 2-1/2" or smaller ports. I have a couple of different dust collectors but I don't use them because I just can't run 4" piping (perhaps some day I will figure out a way to do this--my shop is TINY). My shop vac gets about 150-160 CFM w/o separator. With the separator and network I get about 125-CFM. Absolutely not enough for collection of fine dust.

So the more I read Bill Pentz's site (among others) the more concerned I've gotten that I'm breathing boxcar loads of super-fine dust. That, this dust never settles and every time I enter the shop I breath more of it.

I realize my setup is sub-optimum, but the question is, how much of a price am I paying for it?

Recently I stumbled upon a particle counter that is really geared towards homeowners. It uses a laser to count particles in two sizes.

From the manual:

"Small particles are all particles detected by the DC1100 right down to its detection limit--typically below 1-micron. Large particles are all particles detected above the large particle threshold which is typically around 5 microns."

The meter comes with a table to help interpret the readings:

0 - 25 Excellent Air Quality
25 - 50 Very Good
50 - 100 Good
100 - 350 Fair
350 - 1000 Poor
1000 + Very Poor

So I got this thing and plugged it in in my basement and let it settle for a half hour or so. I had not used any tools for at least 24-hours.

On returning to the shop, it was reading 53/4. You have to add "00" to the end of the readings, so 53/4 translates to 5300 particles total (per cubic foot), with 400 of them being larger than about 5 microns. So far, so good (looking at the table my reading was considered good).

So I switched on the vac and started to cut some MDF. I basically cut the edge off a 3/4" thick piece of 24" long MDF, taking about six swipes. This type of cut (where the blade isn't buried in the wood but rather the left edge of the blade is exposed) seems to generate the largest amount of visible dust above the saw.

I then switched off the saw and watched the meter spike. Approx. one minute after I was done cutting, the meter hit a max of 1955/515. So 195,500 particles (down to 1-micron) and 51,500 larger than 5.0 microns. Nearly twice the 1000+ reading that garners a "poor" rating from their table.

Subsequent readings:

+3 minutes (from peak): 1001/223
+9 minutes (from peak): 499/91
+46 minutes (from peak): 54/2 (now, it could have been low for a while, I had to go upstairs and wasn't paying super-close attention to the meter).

I'm taking for granted that the meter does, in fact, measure down to under 1-micron. However, I will say that the meter is extremely sensitive. Just moving around in the area (within six feet of the meter) causes readings to climb.

Some interesting factors: Above the saw is a vent from the furnace. The furnace has a Honeywell electronic air cleaner. When I close this vent, and let the [new] fine dust air cleaner (down to .3-micron) filter run for just fifteen or so minutes, the meter gets down to 18/1. With the vent reopened the meter almost immediately climbs to 50ish/3-4ish. So my take on this is that, with the vent open, the air from the rest of the house dilutes the super dirty air the table saw creates as I cut. So after cutting the #'s peak, but then fairly quickly start to drop again.

It is too early to make any real generalizations. I hope to use the meter to improve dust collection/filtering in my shop, home, and office (where we service PC's that are full of dust--similar issues to home wood shop).

BTW, the black thing is the meter, the big thing sitting on the floor is my new fine air filter.

[gugie]

Wow, didn't know there were any airborne particle counters designed for home use. Found this: http://allergyclean.com/dylos.htm, which seems to be the unit you're using.

I'm in the semiconductor industry, do a lot of work particle reduction, and am one of the few people I know who have actually ready either the FED STD 209 (obsolete) or ISO 14644 documents. I haven't seen any cheap airborne particle counters, this looks very interesting. Since most of these things are sold to determine cleanroom cleanliness, sensitivity and accuracy are important. For home use, I can imagine making one on the cheap, with results "good enough".

[jking]

On returning to the shop, it was reading 53/4. You have to add "00" to the end of the readings, so 53/4 translates to 5300 particles total (per cubic foot), with 400 of them being larger than about 5 microns. So far, so good (looking at the table my reading was considered good).

Clarify something for me. You get the reading of 53/4 & compare this to the table to determine "cleanliness ranking". Then you would add the "00" to the end to get the number of particles per cubic foot. Did I understand correctly?

I'm also curious where you bought the particle counter.

[lkazista]

So I switched on the vac and started to cut some MDF. I basically cut the edge off a 3/4" thick piece of 24" long MDF, taking about six swipes. This type of cut (where the blade isn't buried in the wood but rather the left edge of the blade is exposed) seems to generate the largest amount of visible dust above the saw.

I then switched off the saw and watched the meter spike. Approx. one minute after I was done cutting, the meter hit a max of 1955/515. So 195,500 particles (down to 1-micron) and 51,500 larger than 5.0 microns. Nearly twice the 1000+ reading that garners a "poor" rating from their table.

OK - I am now good and freaked out.

I really gotts get around to wiring up that 220 outlet for the new dust collector.

Happy Breathing.

Lee

[cgallery]

Clarify something for me. You get the reading of 53/4 & compare this to the table to determine "cleanliness ranking". Then you would add the "00" to the end to get the number of particles per cubic foot. Did I understand correctly?

I'm also curious where you bought the particle counter.

Yes, the meter does it work in particles per .01 cubic foot. You multiple by 100 if you want those #'s in particles per cubic foot. The table they supply to give you an idea of the air quality, though, is in the .01 cubic foot realm.

Meter was purchased from www.americanallergysupply.com, but they can be purchased from the manufacturer (www.dylosproducts.com) too. The American Allergy Supply site has some interesting reading and some interesting tests w/ box fans and filters.

[cgallery]

OK - I am now good and freaked out.

I really gotts get around to wiring up that 220 outlet for the new dust collector.

Happy Breathing.

Lee

It would be interesting to see how the addition of a Shark Guard would have impacted my #'s. A good dust collector is important, but I don't imagine it would have done that much better at getting the dust ejecting from the top of my blade.

[LCHIEN]

according to the allergyclean website, the Dylos meter retains a history by the minute or hour so you can see the air quality change as you cut and then the filters do their work. Much better than having to stay around and take readings.

[lkazista]

It would be interesting to see how the addition of a Shark Guard would have impacted my #'s. A good dust collector is important, but I don't imagine it would have done that much better at getting the dust ejecting from the top of my blade.

Agreed, my point was in the same vein, EVERY bit helps keep the air clean, but a good DC system is the main line of defense. I already run a Delta air scrubber, but my DC is still sitting in the corner of the basement waiting for a 220 line to plug into.

Lee

[jackellis]

I don't have room for a dust collector in my current shop. Period. I use a shop vac and probably spend as much time cleaning up (like that master of cleanliness Rod Kirby) what the shop vac does not capture from the dust ports as I do machining stuff. Helps keep the amount of residual dust down significantly.

And then I wear a respirator when I'm doing a lot of machining. I know it works because without the respirator, I'd get terrible sinus headaches from all the sawdust.

The new shop in a home we're hoping to build soon will have a dust collector and an air cleaner.

[ejs1097]

So if I'm interpeting your numbers correctly, your shop is doing pretty good and better then you initially thought?

cutting MDF like you did is probably one of the messiest test you could perform and the room returned to 'Fair' in 3 minutes, then to 'good' in 9 minutes?

[cgallery]

So if I'm interpeting your numbers correctly, your shop is doing pretty good and better then you initially thought?

cutting MDF like you did is probably one of the messiest test you could perform and the room returned to 'Fair' in 3 minutes, then to 'good' in 9 minutes?

I think it is doing as well as many shops w/ dust collectors, actually. At least that is what I take away from reading some of the BP posts.

But based upon my observations of not only my shop but others as well, I imagine the single fastest way to reduce airborne dust is to add a Shark Guard with overhead collection. At least on the table saw (which I think is a particularly difficult tool to collect from).

I have nothing to back this up other than my gut (I don't own a Shark Guard and am trying to arrange w/ a friend that has one to borrow his for a day or two but we have both been pretty busy and it has been pretty hit/miss).

[steve-norrell]

I then switched off the saw and watched the meter spike. Approx. one minute after I was done cutting, the meter hit a max of 1955/515. So 195,500 particles (down to 1-micron) and 51,500 larger than 5.0 microns. Nearly twice the 1000+ reading that garners a "poor" rating from their table.

Subsequent readings:

+3 minutes (from peak): 1001/223
+9 minutes (from peak): 499/91
+46 minutes (from peak): 54/2

Interesting and helpful data. It does show how quickly and effectively DCs and air cleaners work. However it also shows why a respirator is needed.

Right after cutting the MDF, and while the operator is still standing near the saw, air quality was a lot worse than just 'poor'. In fact, it didn't get into the good range for at least 10 minutes. Point is, that the operator is breathing the particle-laden air during and immediately after the cutting operation.

Don't get me wrong! This is not a critique of the data, the use of dust collection and air cleaners, or the device itself. Rather, the data show the merit of using respirators, especially when one is sensitive to wood (and MDF) dust.

Its good and helpful information. Thanks.

Regards, Steve

[cgallery]

Don't get me wrong! This is not a critique of the data, the use of dust collection and air cleaners, or the device itself. Rather, the data show the merit of using respirators, especially when one is sensitive to wood (and MDF) dust.

Regards, Steve

Absolutely, I couldn't agree with you more. The point is to get a baseline and find out where improvement is needed.

So far I've only cut 12 linear feet of MDF. I haven't tried any tools but the saw. I purposely didn't have a new fines air filter (down to .3-micron) running, cause I want to see before and after.

But in the final analysis, if you wear a respirator, you're probably guaranteed really clean air. That is what I plan to do while I figure out ways to reduce the amount of time I need to wear one by using the gadget.

[steve-norrell]

The point is to get a baseline and find out where improvement is needed.

So far I've only cut 12 linear feet of MDF. I haven't tried any tools but the saw. I purposely didn't have a new fines air filter (down to .3-micron) running, cause I want to see before and after.

But in the final analysis, if you wear a respirator, you're probably guaranteed really clean air. That is what I plan to do while I figure out ways to reduce the amount of time I need to wear one by using the gadget.

I will add that I do have a Shark Guard and almost always use a ZCTP. Notwithstanding the merits of the ZCTP, it does inhibit dust collection through the port at the back of the BT3100, leaving plenty dust above the table.

The top dust port on the Shark Guard goes a long way toward fixing this. Mine is hooked up to a large (6.5 HP) ShopVac, but that does not get ALL the dust even when the ShopVac is attached ONLY to the Shark Guard (in stead of both DC ports).

Now that my scientific curiosity (a carry-over from a previous life) I may have to get one of those devices.

Boy, to I love to tinker . . . . As they say, "If in ain't broke you don't have to fix it, but that doesn't mean you can't try to make it better."

Regards, Steve

[cgallery]

I have spoken to Dylos and they have agreed to a group purchase. Kim will even individually ship the units to each purchaser for 2% above actual UPS (doesn't get any better than that).

The discounts are substantial and will depend on the size of the group (obviously), 25 being the minimum.

Here is some pricing:
Qty. 1, 1-micron, $159.95 each (MSRP)
Qty. 25, 1-micron, $103.99 each.
Qry. 50, 1-micron, $99.19 each.

Qty. 1, .5-micron, $219.00 each (MSRP)
Qty. 25, .5-micron, $142.99 each.
Qty. 50, .5-micron, $136.99 each.

Roger (developer) has agreed to go to Home Depot for me and pickup some MDF. He will saw/sand some MDF and some pine and compare and contrast the .5 and 1-micron units to each other. Either he or I will post the results.

Still some details to be worked out, but not a bad deal overall.

Looks promising.