Dust Collection Performance using Dylos Meter [Archive] - Sawmill Creek Woodworking Community

Greg Funk

02-12-2008, 11:53 PM

I received my Dyloc DC1100 today so I thought I would run a few tests. Following are the results:

House

In the morning I took measurements in the Kitchen and Master Bedroom. Both were between about 28-35 for the 1um reading and around 3-5 for the 5um.

Later in the evening after dinner the kitchen reading had gone up to just over 100. I let it run for a couple of hours and it dropped to around 50. No idea why it went up so high.

Workshop

I have a 2HP Taiwanese cyclone in a room separate from the main shop. Air returns through 2 - 2'x2'x4" filters.
When I started the test the shop had about the same reading as my house (33/4). I turned on the dust collector and noticed the readings went up within a few minutes to a peak of 115/21. I had lunch and came back in about an hour and the reading was down to (29/1).

My worst dust generator is the Unisaw so I took a 14" long piece of 1" fir and cut 23 - 1/16" strips. The readings peaked in about 5 minutes to (2817/648). I then left the shop with the dust collector on to see how long it would take to get the air quality back to normal. After 90 minutes the readings were back down to (33/2).

For the next test I turned off the dust collector and cut another 23 strips. This time the readings peaked at (6048/1941). Again I left the shop and waited however this time I left the DC off. As you can see in the attached graphs after 1 hour the readings were still just above the peak readings I obtained with the DC on. As I was impatient I turned the DC back on about 95 minutes after making the cuts. About 80 minutes later the readings were back down to (35/0).

I left the DC running and found the best readings I obtained were 17/0 which is better than inside my house.

The attached graphs show the particle counts over a 6 hour period for both the 1 and 5um particles. Both graphs use the same data but are plotted on log and linear scales. The straight lines of the log graphs confirm that the dust particle counts decrease exponentially over time and much faster with the DC on. The left scale is for the 1um counts and the right scale is for 5um.

Hopefully others will post their data once they receive their meters.

Greg

Steve Rozmiarek

02-13-2008, 1:16 AM

Greg, what do you use for dust collection on the unisaw? What are you using for a filter on your cyclone? And, do you think the room divider filters make a lot of difference?

Greg Funk

02-13-2008, 1:25 AM

Greg, what do you use for dust collection on the unisaw? What are you using for a filter on your cyclone? And, do you think the room divider filters make a lot of difference?
Good questions Steve.
The Unisaw is connected with a 5" port on the bottom. I have a Shark Guard but haven't installed it yet. I expect I would get rid of much of the dust once I hook it up. The cyclone filter is a 5um bag. I don't think it is very good. I don't know how effective the room filters are yet but now that I have the meter I'll be able to measure soon enough. They are rather loosely installed in a rectangular opening but not sealed around the edges.

Greg

Mike Goetzke

02-13-2008, 8:33 AM

Phil Thien

02-13-2008, 8:47 AM

I hope you're going to post results w/ the SharkGuard soon. I'm not a gambling man, but I'd bet a blade that the SG will dramatically reduce that spike.

Also, what kind of heating/cooling arrangement do you have? And if it is forced air, were there any vents running?

Greg Funk

02-13-2008, 10:22 AM

Mike: I was a little surprised as well. I often leave my DC on while I am working on machines but may let it run a little longer afterwards.

Phil: I agree the SG should take away most of the extra dust. The problem for me is I still use the Tablesaw a lot with a crosscut sled in which case I wouldn't have the SG connected either. I have radiant heat so not much air movement there. I normally keep the shop between 12-14 C. When I'm working in there running the tools it usually warms up a few degrees.

Greg

Greg Peterson

02-13-2008, 11:55 AM

Keeping an eye on this thread.

I'm still waiting to hear from Dylos. They haven't processed my order yet. Anyone else still waiting to hear from Dylos? I don't want to contact them yet as I understand they were still trying to fulfill the orders over the weekend.

Jack Porter

02-13-2008, 12:11 PM

Greg, my order has not been processed yet either.

Art Mann

02-13-2008, 12:34 PM

Thank you very much! That is good information that really isn't available anywhere else. I would really like to see you post more results as time goes by.

michael osadchuk

02-13-2008, 12:53 PM

Greg Funk

02-13-2008, 1:08 PM

greg.... thanks for posting your initial results......

an interesting aspect of the particle readings over time is the natural settling rate of particles of different sizes (and settled particles, not removed from a room, getting "stirred up" by normal human activity as well); I recall on one of these threads linked to the Dyclos purchase someone had posted a settling chart from which I jotted the following figures:

10 microns - settle in 10 minutes
5 m - settle in 40 minutes
2.5 m - settle in 2.8 hrs.
1 m - settle in 16 hrs.
.5 m - settle in 2.9 days

I also jotted down that Phil Thien saying his experience suggests that particles 1 micron and larger settle in a half hour or less.

I seems like your filters between the cyclone enclosure and the workshop are working well.

It will be interesting to see how well powered air filteration units that some of us hang from the ceiling work.

It suspect that dust collection at source is going to prove to be a "good thing" to capture the respirable particles in addition to the dust chips - presumeably we don't want to wait an hour after a table saw operation for the small particles to get collected by a dc unit/air filter or settle.

I haven't yet received by 1/5micron Dylos unit, but got a notice that it was sent Feb. 1 by US Postal Service to my Canadian home so would expect it soon.

thanks again

michael
Thanks for the comments Michael.

Part of the reason I ran these tests was to determine whether I should upgrade by DC system. I have all of my pipes under the slab and they are not layed out in the most efficient pattern. As a result my system has a fair amount of static pressure losses and the cyclone I am using is marginal. It seems to keep the pipes clear although I can run into problems if I let too many wood 'strips' or bigger pieces of wood into the collector. I had to reach down into the pipes and manually pull out some sticks that weren't getting pulled up once.

In any case I'm not really convinced now that a more powerful DC would make much of a difference. I can't really see it preventing sawdust from coming off the top of the tablesaw. Maybe it would clear the air a little quicker afterwards. I'll wait and see what some other users post.

Greg

Rich S Kelly

02-13-2008, 2:09 PM

I received my Dylos 1/5 monitor last Thursday and have taken a limited amount of readings. I have not been as thourough as Greg in recording data but thought I would throw in some of what I have observed so far. I have a 400 sq ft basement shop with a Oneida 2hp cyclone and a Jet 1000 air filter. My base readings have been in the 120/25 range. If I turn on the air filter the readings drop to around 20/ 2 within 5 minutes. I cut about 30 linear feet of melamine shelving on the table saw with the cyclone on and got readings of 1500/350. After 6 minutes of the air filter running they were 250/34. I did not observe any readings after that. After hearing of the possible poor performance of some of the cyclone external filters I took readings near mine. From the mentioned base of about 120/25 I turned the cyclone on and placed the Dylos near the filter. Readings immediately started to drop and went down into single digits for the small particles and zero for the larger. So far I have been very surprised how quickly the Jet filter clears the air and that it produces low small particle counts. Also happy so far with the limited cyclone filter data I have taken.

Once again another thank you to Phil for working up the group purchase.

Rich

Greg Funk

02-13-2008, 2:46 PM

Thanks Rich,

Any idea what your outdoor measurements are?

Mine are quite high compared to indoors - 650/24. I think we are starting to see some pollen.

Greg

Rich S Kelly

02-13-2008, 5:40 PM

Greg Funk

02-13-2008, 5:48 PM

Perhaps working in the shop is not as harmful as some would have led us to believe. It appears the air is significantly cleaner in the shop than outdoors.

Greg

Bob Malone

02-13-2008, 5:57 PM

Greg, They had well over 100 orders (Kudos to Phil) and they are moving through them at a steady pace. I was contacted last week to say mine was on the way up to Canada so I expect it this week.

I am curious to test my shop too!

Bob in Calgary

Walt Nicholson

02-13-2008, 6:20 PM

I am really thankful to all for posting this information and hope that all who bought one of these units will post their readings also. I know I will as soon as the budget allows a purchase. I have always been a little leery of the volumes of numbers spewed forth by self proclaimed experts (especially those who derive income from the sale of related products) about how "cutting one board with a hand saw, etc. etc." is going to put us all in the hospital with lung disease. Good health in the shop should be everyone's priority and it is refreshing to get numbers from folks who have nothing to gain but their own good health. It would be interesting to see what the count is inside the house just after you (or the LOML) have vacuumed a room compared to what is considered dangerous by the "pros". Maybe the sky isn't falling after all and perhaps (with reasonable care and reasonable equipment) we can live to a ripe old age and enjoy the wonders of working with wood. If this post is deemed offensive please remove it and I will go hit myself in the head with some hickory or something.

Greg Peterson

02-13-2008, 6:22 PM

Bob,

I figured they were keeping pretty busy getting these out. I'm looking forward to getting data on my shop space and living quarters too. I'm sure that even the .5 sized particles floating about in the house are not the nasty kind one finds in the wood shop.

I wonder what size particle pet dander is? Two cats and a dog may prove interesting.

John Newell

02-13-2008, 7:37 PM

I just went outside and got a reading. Higher than I expected showing 350/12 in Omaha, NE. That would explain somewhat the much lower readings on the second floor of the house than the first floor with the necessary door opening/closing.

Rich

Perhaps working in the shop is not as harmful as some would have led us to believe. It appears the air is significantly cleaner in the shop than outdoors.

Greg

I have been informally f@rting around with mine and got results very much like Rich Kelly's (I'm in exurban Boston). I let the unit run in the shop and got consisten 90/1 readings. I then turned on the scroll saw and cut some maple - readings went to almost exactly outdoor levels while cutting and then settled quickly. (No DC in place on the scroll saw.) If nothing else, I now understand why people with lung issues are told to stay indoors on smoggy days.

Rick Moyer

02-13-2008, 7:48 PM

I'm not involved in the study here but wanted to say thanks to all who have posted or will post their results. I am weighing out my options for dust collection/air filtration and this information is greatly appreciated.

Mike Goetzke

02-13-2008, 9:14 PM

Wilbur Pan

02-13-2008, 11:25 PM

Surprising results - at least to me. From your test it looks like your cyclone is working as an air filter system. Does this mean we should let our DC systems run for some time after using a tool? I get my meter next week. I have a canister type DC and an air filtration unit. Looks like it would be interesting to try a combination of having the machines on/off.

Thanks for sharing your info,

Mike

I agree -- it would be very interesting to see how an air cleaner affects dust particle readings.

I got to the group buy thing late -- now I'm sorry I didn't get in on purchasing one of these dust meters. :(

Bob Antoniewicz

02-14-2008, 12:10 AM

I am curious how the numbers look with a sander, planer or bandsaw.

The surprising thing about the numbers you have shown is that you do a bunch of cuts and have to wait a while outside the shop for the levels to come down.

One other curiosity - what were the numbers if you just walked around the shop a little while? Can you stir enough dust doing that?

Your machine is giving particle counts - is there a conversion factor to mg/M**3?

Bob A.

Greg Funk

02-14-2008, 12:26 AM

The surprising thing about the numbers you have shown is that you do a bunch of cuts and have to wait a while outside the shop for the levels to come down.

One other curiosity - what were the numbers if you just walked around the shop a little while? Can you stir enough dust doing that?

Your machine is giving particle counts - is there a conversion factor to mg/M**3?

Bob A.
I didn't have to leave the shop I just had other things to do. I just cut up some scrap boards. The smell of freshly cut fir was reasonably strong but I wouldn't normally wear a mask or leave the shop under those conditions.

I walked around the shop a little but it's pretty easy to keep my floor swept clean so other than some air currents there isn't much to stir up dust.

I don't believe there is a simple conversion to mg/m^3 which measures the weight of dust/volume. The meter doesn't really give much info on the distribution of particle sizes so it would be difficult to determine the mass of the measured particles.

For me it is enough to do comparative measurements. For example, tonight we lit 17 little candles for my son's birthday. The cake was about 15 ft away from the meter and when he blew out the candles the readings jumped up almost immediately to around 2000. After 4 hrs they were down to 150 or so. This is beginning to tell me that the shop environment is not all that different than what we experience with everyday living.

Greg

Bob Antoniewicz

02-14-2008, 1:10 AM

I didn't have to leave the shop I just had other things to do. I just cut up some scrap boards. The smell of freshly cut fir was reasonably strong but I wouldn't normally wear a mask or leave the shop under those conditions.

...
...

For me it is enough to do comparative measurements. For example, tonight we lit 17 little candles for my son's birthday. The cake was about 15 ft away from the meter and when he blew out the candles the readings jumped up almost immediately to around 2000. After 4 hrs they were down to 150 or so. This is beginning to tell me that the shop environment is not all that different than what we experience with everyday living.

Greg

Thanks for the information. The engineer in me wants to figure out the absolute numbers from the data you've given. (What was the air volume sample that gave the reading of 2000 particles? :-)

But your observation in relative terms holds real value.

Thanks.

Bob A.

Matt Lentzner

02-14-2008, 1:20 AM

Guys,

I think it is unwise to assume that all dust of the same micron size is equal. A reading of 650 wood dust is likely much more dangerous than a 650 outside of pollen (unless your hayfever is really really bad).

I can't image that inhaled pollen will last very long inside the lungs - it's pretty delicate stuff. Wood particles, on the other hand, being made of cellulose, are apparently very pesistant. Furthermore many are loaded with natural pesticides that can do all sorts of nasty things.

Regardless, any data that is collected is fantastic. Just establishing a "clean" baseline is great since one can evaluate their dust collecting systems against it. Keep reporting - I'm keeping a look out for more data!

Matt

Greg Funk

02-14-2008, 1:40 AM

Guys,

I think it is unwise to assume that all dust of the same micron size is equal. A reading of 650 wood dust is likely much more dangerous than a 650 outside of pollen (unless your hayfever is really really bad).

Matt,
I suppose you could be correct but I really don't know what is in the air outdoors. I surmised pollen but it could be coal dust from the coal port 10 miles away or particulate from vehicle exhaust or something else. It is a little unfortunate that there aren't any studies that I am aware of that would allow one to conclusively determine whether a particular particle count was harmful or not. In any case I think this meter will assist me in minimizing how much junk I am breathing:)

Greg

John Stevens

02-14-2008, 7:13 AM

Your machine is giving particle counts - is there a conversion factor to mg/M**3?

Hi, Bob. If you're interested in using the particle counts to see how the dust levels compare to OSHA's standard, here's some more info.

It was reported in an earlier thread on this forum, that the OSHA standard is 1mg dust per cubic meter. (http://www.sawmillcreek.org/showpost.php?p=740021&postcount=113) I did a little digging (google "osha wood dust) and found that this is incorrect. The standard is a little more complicated than that, because it depends on the "time weighted average" of a person's exposure to the dust.

For a person who will be exposed to the dust for up to ten hours a day, and up to 40 hours a week, the "permissible exposure limit" for "total dust" is 15mg/m^3. If you limit the dust to what is called the "respirable fraction," the limkt is 5mg/m^3, still five times the figure stated in the earlier thread. OSHA also gives these exposure limits as particle numbers as measured by "impinger samples counted by light-field." These particle number limits are 50 million particles/cu.ft. for total dust and 15 million particles/cu.ft. for the respirable fraction of dust.

Several other facts are worth noting.

First, NIOSH (the National Institute for Occupational Safety & Health, a federal govt agency) and the ACGIH (American Conference of Governmental Industrial Hygienists (a private organization) both recommend limits of 1mg/m^3 for hardwood dust for a full work work day (10 hours for NIOSH and 8 hours for ACGIH) and 40 hour workweek, but for short term exposures of 15 minutes, up to four times a day, the ACGIH would allow exposures of up to 10mg/m^3 for hardwoods.

Second, since all these numbers are advocated by parties with various political agendas, it's worth asking what the labor unions are asking for. After all, they're the ones with an interest in exaggerating the risk in order to win concessions in other areas from management. In 1985, the United Brotherhood of Carpenters and Joiners of America of the AFL-CIO petitioned OSHA to change the standard to 1mg/m^3 for hardwoods and 5mg/m^3 for softwoods. OSHA rejected that standard after reviewing the health evidence presented.

Third, it's worth asking what the courts think of all this, because they're (theoretically) neutral and only interested in what the law and the science indicate. The OSHA standard for the time between March of 1989 and March of 1993 was 5mg/m^3 for total dust for hardwoods. The federal Court of Appeals for the Eleventh Circuit ruled that the facts presented to OSHA in support of that standard were not sufficient to support it under the law. AFL-CIO v. OSHA, 965 F.2d 962 (11th Cir. 1992).

Sorry if this has been a long post that seems like thread drift, but I think that if we're going to try to use the particle meters to compare the dust levels in our shop with the OSHA standard, then it would be worth considering these things.

Thanks to all who have contributed to this thread. It's important that we understand the risks we're subjecting ourselves to so that we take appropriate precautions. But by the same token, it's important that we don't unreasonably overestimate the risks and deprive ourselves of activities and products that we enjoy.
Regards,

John

John Newell

02-14-2008, 7:35 AM

I think it is unwise to assume that all dust of the same micron size is equal. A reading of 650 wood dust is likely much more dangerous than a 650 outside of pollen (unless your hayfever is really really bad).

Good point...I think. I have never gotten sick walking around outside...I have gotten sick breathing tropical hardwood dust. Whether there are more subtle or longer-term issues...dunno...urban air can be full of pretty nasty particles, but so can the shop.

Lee DeRaud

02-14-2008, 9:51 AM

I also think it's great to share our results, but, I shot Phil an e-mail today and suggested it might be nice to post results at his sight so we can consolidate the results. He warned that many forums, like SMC, do not allow reference to other web addresses but maybe an exception is due for this subject? Any ideas/suggestions? Maybe SMC could have a dedicated forum for DC measurements - even if it's only temporary?I haven't looked at Phil's site, but what you're suggesting (probably) isn't a problem:

3. External Linking
Links to other websites are allowed in posts. In fact, they are encouraged. However, links for the sole purpose of marketing, generating traffic to a site, or any other commercial advertisement deemed to solicit commercial benefit are not allowed. Links to other public or private forums are not allowed. Links should be submitted as references, for the sole purpose of generating or supporting discussions on SawMill Creek.

Greg Funk

02-14-2008, 10:50 AM

John Stevens

02-14-2008, 12:47 PM

Do you have any idea what particle size they were talking about for those impinger samples.

Hi, Greg. Unfortunately, I don't have any more info. Maybe I'm just missing it, but I can't find any info on particle size for wood dust, which falls under the category of "nuisance dust" in the applicable OSHA regulation. This is odd, because the same table in the same regulation gives sizes for quartz dust. If I'm correct that the reg does not specify particle size for nuisance dust, then my guess is that the specific info on the particle sizes is contained in some document that is available to the public somewhere, but I don't know where, because administrative law ain't my bag. I'd also guess that lots of info on which particle sizes ought/ought not to be measured was presented to OSHA at the time it made its regs, and all such evidence has been incorporated into an official "record" that is available to the public for inspection, again, somewhere.

The info I got was from OSHA's web site, which in turn is quoting OSHA's regulation that's published in the Code of Federal Regulations (CFR). FWIW, the citation is 29 CFR 1910.1000, tables Z-1 (see footnote "(f)" in that table) and Z-3 (see footnote "d" in that table). These tables can be found online at:
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9992
and
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9994
respectively. Unfortunately, the text doesn't say anything about particle sizes.

By the way, I have to add an important qualifier to my last post. From poking around the internet and reading correspondence between a guy at the CDC (Centers for Disease Control) and another guy at NIOSH, there's apparently a lot to know about the various ways of collecting dust particles for counting, the point being that some ways are much more accurate than others.
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=21109
I should have noted that in my earlier post, because I think that by failing to do so I gave readers a false sense that the particle counts made by us "lay people" would be the same as those made by NIOSH personnel. BTW, NIOSH is a branch of the CDC, and does the testing for OSHA: http://www.cdc.gov/niosh/about.html

Again, sorry for the long, boring post, but I hope this helps somewhat.

Regards,

John

John Newell

02-14-2008, 3:01 PM

Greg Funk

02-14-2008, 3:09 PM

There is more to this than just particle size, though, no? Some woods produce toxic reactions wholly apart from the issues of having particles lodged in your lungs. That is a non-professional observation from my own experience...but I think it's correct.
Certainly some woods like cedar and tropical woods are more likely than others to cause problems with certain people. And you can develop an allergy to a few or all types of wood dust. Myself, I haven't really noticed sensitivity to any of the wood species I normally work with so I am concerned with wood dust in general.

Greg

Wilbur Pan

02-14-2008, 3:21 PM

It was reported in an earlier thread on this forum, that the OSHA standard is 1mg dust per cubic meter. (http://www.sawmillcreek.org/showpost.php?p=740021&postcount=113) I did a little digging (google "osha wood dust) and found that this is incorrect.

I guess I should apologize for the error, since I was the one that made that post.

John Stevens

02-14-2008, 4:02 PM

I guess I should apologize for the error, since I was the one that made that post.

Hi, Dr. Pan. For what it's worth, I think that it was a very understandable mistake, considering that your figure was consistent with the NIOSH and ACGIH recommendations...and administrative law ain't your bag, neither. ;)

I also want to take this opportunity to say that although I haven't agreed with everything you've written on this topic, I've still gained a lot from your contributions, and I'm grateful for your continuing participation in threads like these. I apologize if my link to your earlier post seemed to single you out. I tried to avoid that by not mentioning your name, but I did want to give people a fast way to go back and check the figure that had been given earlier for OSHA standard so that any confusion in that regard would be cleared up.

Regards,

John

Wilbur Pan

02-14-2008, 4:03 PM

For a person who will be exposed to the dust for up to ten hours a day, and up to 40 hours a week, the "permissible exposure limit" for "total dust" is 15mg/m^3. If you limit the dust to what is called the "respirable fraction," the limkt is 5mg/m^3, still five times the figure stated in the earlier thread. OSHA also gives these exposure limits as particle numbers as measured by "impinger samples counted by light-field." These particle number limits are 50 million particles/cu.ft. for total dust and 15 million particles/cu.ft. for the respirable fraction of dust.

Thanks for that very informative post. Do you have any idea what particle size they were talking about for those impinger samples. Those limits seem quite high relative to the numbers I have been seeing where the highest reading is was about 50,000/cu ft. Perhaps they measure smaller particle sizes.

Just to put some real world values on these numbers:

I think "respirable fraction of dust" refers to dust particles on the order of 1 micron in diameter or so. If you do the conversion, 1 cubic micron is 6.1 × 10-14 cubic inches. 15 million dust particles/cubic foot would mean a total volume of 0.000000915 cubic inches of wood dust/cubic foot. A typical shop size is 20' x 20' x 10', or 4000 cubic feet, which allows you 0.00366 cubic inches of respirable dust in your entire shop.

Now, the Forrest Woodworker II table 10" saw blade comes with 3/32" and 1/8" kerfs. (I'm not picking on Forrest, I just wanted to pick a table saw blade that anyone would want on their tablesaw.) If you make a cut 3/32" wide in 3/4" thick stock, you'll only need a cut of 1/20" long to make that 0.00366 cubic inches allowed in your shop. Of course, not all the wood in that saw kerf will be pulverized into 1 micron particles. But even if only 0.1% of the wood gets converted into 1 micron particles, and this is a highly conservative estimate, a 52" cut will get you to the same point, or just a bit more than ripping one 4'x8' sheet of plywood in half.

And since I was the one that made the mistake before, I'll amend my previous analysis by saying that if limiting your exposure to 15 mg/m3 of hardwood dust is your goal, 6.6 inches of sawing with a Lie-Nielsen dovetail saw in 3/4" stock will get you there, assuming complete conversion of the wood in the kerf to dust particles. If you are making dovetails in 3/4" stock, and for simplicity assume that each side of a pin or tail is 3/4" (it actually will be 0.756" for a 1:8 dovetail angle), that's just under 9 cuts, or not even enough to finish a dovetail joint with 3 pins/tails.

My main point is that regardless of what the exact numbers or limits you set on wood dust exposure, it doesn't take all that much wood cutting to get you there, which is why having good dust management is key.

Greg Funk

02-14-2008, 4:26 PM

Now, the Forrest Woodworker II table 10" saw blade comes with 3/32" and 1/8" kerfs. (I'm not picking on Forrest, I just wanted to pick a table saw blade that anyone would want on their tablesaw.) If you make a cut 3/32" wide in 3/4" thick stock, you'll only need a cut of 1/20" long to make that 0.00366 cubic inches allowed in your shop. Of course, not all the wood in that saw kerf will be pulverized into 1 micron particles. But even if only 0.1% of the wood gets converted into 1 micron particles, and this is a highly conservative estimate, a 52" cut will get you to the same point, or just a bit more than ripping one 4'x8' sheet of plywood in half.
Wilbur,

Interesting analysis but I don't think you have a good basis for your assumption that .1% of the wood gets converted to 1um particles. Based on literature I have seen the bulk of the fine particles are >10um in size. The vast majority of the output of a saw cut is in the form of shavings or chips. Of the small portion that gets converted into fine dust there is a much smaller portion that gets converted into respirable particles.

One data point I would provide is that based on the measurements I took where I saw 500,000 particles/cu-ft 1um or smaller and assuming for the worst case that all particles were 1um in diameter, my calculations would indicate that the 1um particles contribute .005 mg/m^3 to the dust load. For the larger particles it is more difficult as I believe the meter counts all particles larger than 5um. If you assume the average larger particle size is 20um then you would get a load of just over 7mg/m^3 from the larger particles.

In any case I agree with your conclustion regarding the importance of good dust collection.

Greg

Wilbur Pan

02-14-2008, 5:08 PM

Interesting analysis but I don't think you have a good basis for your assumption that .1% of the wood gets converted to 1um particles. Based on literature I have seen the bulk of the fine particles are >10um in size. The vast majority of the output of a saw cut is in the form of shavings or chips. Of the small portion that gets converted into fine dust there is a much smaller portion that gets converted into respirable particles.

Take a look at the Report on Carcinogens Background Document for Wood Dust (http://ntp.niehs.nih.gov/ntp/newhomeroc/roc10/WD.pdf), from the December 13 - 14, 2000 Meeting of the NTP Board of Scientific Counselors Report on Carcinogens Subcommittee, which was prepared for the U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program.

Table 2-6 on page 20 of this report measures the distribution of particle size from various woodworking operations involving oak, ash, beech, and particle board. The percentage by mass of 0.65–1.1 μm particles is 0.5-3.0%, which makes my guesstimate of 0.1% not unreasonable.

This set of data lumped dust particles 9 μm and larger in one category. The percentage of all particles less than 9 μm from these woodworking operations ranged from 27.4-55.6%.

Greg Funk

02-14-2008, 5:15 PM

Take a look at the Report on Carcinogens Background Document for Wood Dust (http://ntp.niehs.nih.gov/ntp/newhomeroc/roc10/WD.pdf), from the December 13 - 14, 2000 Meeting of the NTP Board of Scientific Counselors Report on Carcinogens Subcommittee, which was prepared for the U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program.

Table 2-6 on page 20 of this report measures the distribution of particle size from various woodworking operations involving oak, ash, beech, and particle board. The percentage by mass of 0.65–1.1 μm particles is 0.5-3.0%, which makes my guesstimate of 0.1% not unreasonable.

This set of data lumped dust particles 9 μm and larger in one category. The percentage of all particles less than 9 μm from these woodworking operations ranged from 27.4-55.6%.
OK I'll read the paper.

You may also want to look at a paper - "Comparison of wood-dust aerosol size-distributions collected by air samplers" from the Journal of Environmental Monitoring (http://www.rsc.org/publishing/journals/EM/article.asp?doi=b312883k) in particular have a look at figure 2.

Greg

Greg Funk

02-14-2008, 5:31 PM

Table 2-6 on page 20 of this report measures the distribution of particle size from various woodworking operations involving oak, ash, beech, and particle board. The percentage by mass of 0.65–1.1 μm particles is 0.5-3.0%, which makes my guesstimate of 0.1% not unreasonable.
Wilbur,

They are referring to the % (by mass) of particles that are airborne not the % of total wood released by the sawing operation. You may be correct but the article you cited doesn't provide any indication of the amount of wood released as airborne particles.

I suspect you may be close if you were talking about a sanding operation where a much higher percentage of the wood becomes airborne. I know from personal experience that it doesn't take much hand sanding before the environment becomes filled with dust and unpleasant.

Maybe I'll run another test this afternoon with some hand sanding...

Greg

Will Blick

02-14-2008, 7:07 PM

I think Wilburs example is a good one..... regardless if his estimate of .1% is accurate, its a moot point, cause even if its .01%, just 10x the small cut size he based his calcs on, and you get to the same place. Add some sanding, and you probably 10x this again... etc.

We all run the risk of becoming overly analytical with these tools, I am no exception....but I am trying hard to simply use the meter as a benchmark or a reference to comprehend what is going on in terms of dust...specially before, during and after certain shop operations. I am just as interested in the household air, and the ambient air in my city as it compares to others I am not discouraging posts by any means...

I just got my .5/2.5 unit.... As with most meters, I am dumbfounded by the results. First, my house is reading 800/20. Obviously lots of fine particles, not happy about that... I suspect its from carpeting... a vacuum cleaner is a huge dust generator.... I may consider a super hepa system like a Miele...

My shop, which has been idle for a week, registered 100/20... amazing, has more fine particulate than my shop. I will monitor my shop and report back....but I exhaust my Cyclone outside, and I run a continous exhaust.... so I don't fear too many problems, other than while in the process of sanding, cutting, etc. Bill Pentz made a lot of great contributions to this field, but the one that is the most obvious and effective is to use a cyclone and exhaust outside, and/or leave the work space open to the outside, give the dust a place to move. Of course, wearing a good respirator is the most important factor.

But back to results.... I checked outside, a windy day here in the desert... 1800/50... WOW! Its safer to be sanding wood! This can certainly explain a lot of the headaches on windy days....

Whats really interesting is.... i run an expensive .3 micron air filter in my bedroom, huge filter, probably 7 sq ft of media 3" thick... however, the results are no better the the rest of the house. EDITED AND CORRECTED WITH POST BELOW

What I would love to rig up this experiment .... take my 3m respirator filters and force air through them, with the exhaust air feeding the meter..... I am curious how effective these filters are.

Well, lots of experimentation to do....sure wish this thing had a batter pack option... i may rig up one...

As for previous comments regarding the type of particles. I think its obvious, certain particles are allergens to some people, but not to others, just like pollens. Unfortunately, some wood types have a high "hit rate" as allergens. However, from what I have gathered, even if you are not allergic to the particles, high concentrations of any small particles can't be healthy.

Phil Thien

02-14-2008, 7:51 PM

Whats really interesting is.... i run an expensive .3 micron air filter in my bedroom, huge filter, probably 7 sq ft of media 3" thick... however, the results are no better the the rest of the house. Makes me wonder about how substantiated some of the claims these makers have... this meter sure gives us "eyes" into seeing what is actually happening. Of course, I am assuming the meter is accurate.

Will,

Could your HVAC system be at play? Perhaps a forced air system that is changing the air in the room faster than the .3 micron filter can clean it?

For other results posters, it would be helpful to know what kind (if any) HVAC systems are in place where tests are performed.

Thanks,
Phil

Will Blick

02-14-2008, 8:15 PM

> Could your HVAC system be at play?

Sorry, I should have mentioned, I have self contained HVAC system for the bedroom only.

However, I just learned something fascinating with the meter.... when you are full of dust (which it appears we can be, without even knowing it) you can't stand near the meter, cause you become the source of the dust. I was standing by the meter for a minute and hence the results I reported above.... then I left the meter plugged in, went back in 15 minutes and it has been reading 150 ever since.... so lesson learned - get away from the meter, let it settle. So, good news, really expensive air cleaners really work. I bought a new filter for it ($199), since this one has reached its life expectancy of 5 years. IIRC, this one filters down to .3 micron. Anyway, I always assumed it was best to have the cleanest air where you breathe the most, i.e. in your bedroom. Here is a link of the one I own

http://www.austinair.com/healthmate.php

Next I am curious about the effectiveness of HEPA vacuum cleaners. I am convinced most house dust comes from vacuums that stir the dust out of the carpet, the bag / cyclone catches the big particles and the rest shoots out the exhaust, and based on the post above, these particles float around for several weeks, which by then, we have vacuumed again.... carpets are huge dust producers, constantly shedding.... and the beater brushes on the vacuum just add to the problem... sheeeeesh....

Rob Blaustein

02-14-2008, 8:55 PM

Some preliminary results with my 1um/5um unit.
Relevant info: Basement shop, about 13' x 19'. House has forced hot air, furnace/blower in a different room in the basement. I use a 3M ultra allergen 1200 pleated filter in the furnace.

Baseline shop reading fluctuates from 25/0 to 80's/5. If I run my Jet AFS 1000B filter (hanging from my 8 ft ceiling) at medium for 10 min, it gets down to 20/0. I am making some bookshelves and just cut up some 3/4" plywood. I made 6 cuts, each 5 ft long, so I cut about 30 linear ft of 3/4 ply in a 5-10 min period. My DC is a Jet DC1200 with a Wynn upgrade cannister filter, plastic bags below. I run a 4" diam flex hose to the base of the cabinet saw, and a 4" diam flex to my Excalibur overarm guard. The duct runs are quite short so I don't think there is much static pressure loss. Anyway, I was amazed at how good the dust collection was (note: I wasn't running the Jet air filter during the cuts, just the DC). The meter peaked at maybe 150/25 or so. Again, running the air filter for 10 min brought it down to 20-30/0-2. I then applied some edgebanding and noticed that after I ran some 220 grit along the edges to smooth them out, the meter hit the 300/50 range. So I generated more dust in the air with that little bit of sanding than by cutting up the sheet goods with the combined DC from below and above. At some point I'll also check what happens when I don't use the overarm guard DC. I also now want to check what happens in the rest of the house, particularly after the heat comes on. One thing I'm curious about: in the morning when the sun comes into our bedroom through a window above our bed, I can see the scatter from lots of dust--I wonder what the Dylos would read there. I'll keep you posted.
--Rob

Rob Will

02-14-2008, 10:02 PM

I have my Dylos meter set up in the shop.
One of my employees had cleaned up in there this afternoon.
When I went in the shop about 4 hours later, the reading was about 165/35. At that point, I turned on my furnace fan and the particulate count quickly (in about 5 minutes) dropped to 35/1.

The machine room area is 32 x48 16 and my furnace moves about 1200 cfm. This means that the furnace fan would take about 20 minutes to change the air in the shop. If the clean air from the blower disperses evenly within the shop then that means that every 20 minutes I am actually only filtering half of the air. At the end of one hour, I have filtered 7/8 of the air in the shop (???).

So here's the weird part: Why does the reading from the Dylos meter drop so quickly --- when at the end of 5 minutes, I have actually only filtered 25% of the air in my shop?

One possibility would be if my Dylos meter was positioned on the opposite wall from the furnace registers and I am sending over a "curtain" of clean air that washes down the wall and across the meter (?).

One of the tractor companies is sending me to the Daytona 500 this weekend :D!!! so I don't have time to test this. In the meantime, I would be interested in your thoughts on this and if the meter's location within your shop makes a difference (??).

Note: my woodshop furnace is equipped with a purpose-built two-stage air filter and I intend to monitor the negative pressure within the blower compartment (to guard against a clogged filter creating temperature rise problems). So far the furnace based system seems to be many times more effective than my ceiling mounted air cleaner (Delta 3-speed) -- and a lot easier to service:cool::D.

Rob

Greg Funk

02-14-2008, 10:14 PM

So here's the weird part: Why does the reading from the Dylos meter drop so quickly --- when at the end of 5 minutes, I have actually only filtered 25% of the air in my shop?

One possibility would be if my Dylos meter was positioned on the opposite wall from the furnace registers and I am sending over a "curtain" of clean air that washes down the wall and across the meter (?).

Rob,

I suspect something similar in my shop. I went in the shop today and just ran the dust collector for a while. The count dropped from about 100 down to 40. I then shut it off and left it and the count climbed back up to 80 over a 2 hour period. I suspect there are air currents that take a while to settle down.

Do you have a 1/5 or the .5/2.5um version?

Greg

Rob Will

02-14-2008, 10:19 PM

Rob,

I suspect something similar in my shop. I went in the shop today and just ran the dust collector for a while. The count dropped from about 100 down to 40. I then shut it off and left it and the count climbed back up to 80 over a 2 hour period. I suspect there are air currents that take a while to settle down.

Do you have a 1/5 or the .5/2.5um version?

Greg

Greg,
I have the 1/5 version
Rob

Will Blick

02-14-2008, 10:40 PM

I wonder if the speed of the particles effects the readings? This could account for the lower readings.... the particles are there, but the Dylos can't see'em above a certain speed?

Like every tool, lots of experimentation is in order :-(

Rob Will

02-14-2008, 10:43 PM

Will Blick

02-14-2008, 10:46 PM

It does have a fan.....but maybe that is the only accurate air speed it will read the particles. if the inlet has induced air, the total air speed will increase over the sensing device.... just a thought, I see some strange movements also.

Ceiling fans also stir up dust....arggggg.... I can drop a rooms particle count by 50% by turning off the ceiling fan...

Rob Will

02-15-2008, 12:29 AM

I went back out to the shop and moved my meter closer to the furnace air intake rather than on the opposite wall where "clean" air blows directly on it.

It seems that I get smoother data with the Dylos on the end of the room by the air cleaner intake (not too close). This is probably more representative of the overall particle count in the room. The air has had more time to mix and some of the turbulence from the blower has settled down.

On a different note here is my air:
Start - empty shop - no recent activity: 85/5
Furnace blower on for 3 minutes: 75/2
Furnace blower on for 40 minutes: 20/0
Furnace blower off: 29/1
Wait 5 minutes, furnace blower back on: 29/1
Stomp feet to other end of shop and back - blower on - peak reading 3 min later at 1080/138 then started to drop quickly.

Note the 1 micron level at start: 85
After changing the air twice (40 minutes) 1 micron level = 20

If 1 air change = 1/2 of the air gets cleaned....
and two air changes = 3/4 of the air gets cleaned.....
then the "85" count dropping off to about 20 or 30 seems about right.

I'm guessing that the 1 micron level in my shop would never drop below 15

Rob

John Stevens

02-15-2008, 12:56 PM

I think "respirable fraction of dust" refers to dust particles on the order of 1 micron in diameter or so.

Hi, Dr. Pan. I have a question, if you don't mind the imposition. What does the term "respirable" mean? Can non-respirable airborne wood dust cause serious illness? (By "serious illness," I mean something more than sniffles or a little rash on the skin.)

I only ask because I'm wondering if we might be over-emphasizing concern over respirable particles and under-emplasizing concern over non-respirable airborne particles. Thanks in advance for once again sharing your expertise here.

Regards,

John

Wilbur Pan

02-15-2008, 3:50 PM

Hi John,

Actually, the opposite is true.

As most people know, the respiratory tract starts with your windpipe, divides up into the two bronchi that lead to each lung, which then divides into smaller and smaller airways, until you get to the alveoli, which are very tiny thin sacs that are so thin that oxygen simply diffuses right through them and into the blood, while carbon dioxide diffuses from the blood through the alveoli where it is exhaled out. The respiratory tract protects itself primarily through the production of mucus, which traps particles that get into the lungs, and cilia, which are little hairs that line the larger airways of the respiratory tract that move in such a way that they bring the mucous up and out of the lungs, so that you can either hock a goober or swallow it. ;)

Here's a picture of this part of the respiratory tract (http://science.nhmccd.edu/biol/respiratory/bronchiole.htm).

A "respirable" particle is one that can get into the smallest airways of the lungs. A "non-respirable" particle is one big enough that it will get trapped in the cilia or mucous of the larger airways and be carried out of the respiratory tract. After reading through some more sources, it looks like respirable particles are considered to be 5 microns or smaller.

The reason smaller particles are more of a health issue than larger particles is that the smaller particles are the ones that will make it to the smallest airways of the lungs. These airways also are the least protected. They do not make much mucous, they have no cilia to move foreign particles out, and they are very delicate so they get damaged easily.

Here's a picture of the alveoli (http://science.nhmccd.edu/biol/respiratory/alveoli.htm). You can see that they are much more delicate compared to the larger airways. To put things to scale, a 1 micron dust particle is probably about the size of the white space inside the letter "o" in the word "alveolus" in the picture, so you can see how such a small particle can get down to this part of the lung.

As I mentioned above, larger particles tend to get trapped by mucus in the upper parts of the respiratory tree, and are cleared out by the cilia. On the other hand, airborne particles 1 micron or less are just the right size to get down to the delicate small airways of the lungs. This is also why asbestos is so bad for your lungs: asbestos fibers are also just the right size to get down to the small airways of the lungs and cause damage. The same thing is true for cigarette smoke.

Once particles get down to the small airways, the only thing your body can do to try to remove them is to generate an inflammatory reaction to destroy or break down the particles. Unfortunately, this will also further damage the small airways of the lungs, namely destruction of the walls of the alveoli (http://science.nhmccd.edu/biol/respiratory/conditions.htm). (Look at the picture labelled "Emphysema".) This is why this will lead to lung disease like COPD (emphysema). If the particle can't be destroyed, which is the case if it is made of something tough like asbestos or cellulose (sawdust!), it will tend to sit there causing more inflammatory damage.

In a nutshell, I really don't think you can overestimate the potential for damage that respirable dust can do to your lungs. The fact that these dust particles are too small to see and that for the most part, the lung damage occurs slowly over a period of time only adds to the tendency to dismiss this problem.

Wilbur

Wilbur Pan

02-15-2008, 3:54 PM

By the way, since I worry that I keep hijacking this thread, I'd like to ask a question that's more relevant.

What units of measurement are used on the Dylos units? I looked at the Dylos website and couldn't figure it out. So when Rob said that his Dylos read 85/5 with his shop not in use, does that mean a concentration of 85 particles per some amount of air volume, or 85 total particles detected by the Dylos from wherever it was sitting?

Lee DeRaud

02-15-2008, 4:21 PM

Seems like it's just like real-estate: location, location, location. Plus there's a strong dose of activity, activity, activity added to the mix.

I've got the 0.5/5.0um unit. Just to baseline it, I stuck it on a bookshelf in a room that doesn't get much traffic and put it in 'monitor' mode (samples for one minute every hour). I'm seeing 10:1 variations in the readings over a 24-hour span...when I asked the Dylos tech guy about it, he said that 50:1 was not unusual depending on activity in the area and variations in any outdoor air getting into the room.

(I also discovered it can see fog: got an outdoor reading over 10000 early yesterday morning.:eek:)

I'm starting to think these widgets are more valuable for checking long-term trends than this turn-the-saw-on-and-off business.

Steve Leverich

02-15-2008, 5:44 PM

Dr. Pan, this from Phil's first post on the Dylos -

"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)."

Here's the thread -

http://www.sawmillcreek.org/showthread.php?t=73486

I'm surprised this info isn't on the Dylos site, although I'm getting the impression it's a small organization - I'd asked Roger about a PDF manual in an email a while back, and he answered that it wasn't on the site yet - still isn't.

HTH... Steve

Tim Marks

02-15-2008, 5:51 PM

I see that Dylos has raised the price to $200 each. Guess it is the law of supply and demand... SMC has cleared out their inventory for the forseeable future...

John Newell

02-15-2008, 8:02 PM

In a nutshell, I really don't think you can overestimate the potential for damage that respirable dust can do to your lungs. The fact that these dust particles are too small to see and that for the most part, the lung damage occurs slowly over a period of time only adds to the tendency to dismiss this problem.

How much does it matter what the composition is? Is, say, clay dust better than maple dust better than cocobolo dust better than asbestos? Is there a hierarchy, and what factors govern how bad different materials of the same size are?

Rob Blaustein

02-15-2008, 9:47 PM

How much does it matter what the composition is? Is, say, clay dust better than maple dust better than cocobolo dust better than asbestos? Is there a hierarchy, and what factors govern how bad different materials of the same size are?

Well we certainly know about asbestos--it tops that list--but the wood dust is trickier to know about. There are many substances the effects of whose inhallation have been fairly well established (e.g. exposure to silica dust causing silicosis), but my sense is that the data for wood dust, particularly different species, are much less available.

--Rob

P.S. Can we go back to calling Dr. Pan, Wilbur?:D Otherwise we open the floodgates and will soon be using Sir, Professor, Commander, Your Highness, etc...

Bob Antoniewicz

02-15-2008, 11:55 PM

Dr. Pan, this from Phil's first post on the Dylos -

"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)."

...

HTH... Steve

Thanks, thats what I was trying to ask (in my feeble way). Multiply that by 36.8 to get cubic meters. So your 53 turns into
(53 - 4) *100 * 36.8 = 180320 particles per m^3

That must be one heckuva counter on that there gizmo!

Bob A.

Will Blick

02-16-2008, 12:12 AM

Wilbur, fabulous post, thank you for such a clear concise explanation.

So 1 micron and smaller particles, we have no built-in defenses system for, other than inflammation. Easily understood. But are you saying, these particles pass through the thin delicate membrane to our blood? Or do they simply remain lodged in the delicate membrane, causing constant inflammatory response?

I assume only gases can pass through the lung/blood membranes? Or maybe, if the particles are small enough, they too can pass through to the blood?

Air that is highly saturated with water vapor, such as a steam room, contains the smallest size water vapor particles as well. Therefore, I would assume a steam room still represent a good therapy to keep these small dust particles from remaining embedded in the tissue...as a much of the water vapor in in the steam will condense in all areas of the lungs, providing a "washing out" of the small particles - which we have no built-in defense against. I recently read something to this in a book on steam therapy. Your thoughts?

michael osadchuk

02-16-2008, 11:01 AM

Thanks, thats what I was trying to ask (in my feeble way). Multiply that by 36.8 to get cubic meters. So your 53 turns into
(53 - 4) *100 * 36.8 = 180320 particles per m^3

That must be one heckuva counter on that there gizmo!

Bob A.

Bob, thanks for that conversion to particles per cubic meter......
.... does anyone know what the "accepted" conversion number from particles per m^3 to micrograms (ug) per m^3 is?......
.....because it's my understanding that in Canada (and I think also in the U.S.) "acceptable air quality" standards are based on this ug/m^3 calculation.... from a Toronto Star article Jan. 29/08 I understand that Environment Canada's acceptable air quality sets a limit of fine particulate matter of 30 ug/m^3....I'm not sure but I believe Environment Canada using PM 2.5 or the particulate size of 2.5 micron for this standard.....
for example, in Ontario, Toronto and Hamilton led the province of Ontario with the greatest number of days per year with 24 hour readings that exceeded that limit (28 and 16 days, respectively) while the median readings for those places are around 5-6 and 7, respectively....... the same article said downtown Beijing in 2001 had monthly average readings of 70

.....I received my Dylos monitor, a 1/5 micron unit, yesterday.... it seems to work fine; I like the monitor/sampling setting wherein it takes (and stores) an air quality reading once every hour...... I haven't taken it into the workshop yet but initial use in my 'living quarters' seems to emphasize how much human movement stirs up fine particulate after which the readings settle and stay down......

check out this item - HEPA filters may improve cardiovasular health - referencing February issue of the American Journal of Respiratory and Critical Care Medicine

www.cbc.ca/health/story/2008/02/15/hepa-filters.html

..seniors living for 48 hours in an test environment with air filtration had a 8.1% improvement in blood flow, with researchers theorizing that "reduction of indoor air particles... most likely indicates a gerneral improvement in the function of the inner lining of small vessels, including those supplying the heart"

good thread

michael, newmarket, north of Toronto, Ontario

Greg Funk

02-16-2008, 11:21 AM

.... does anyone know what the "accepted" conversion number from particles per m^3 to micrograms (ug) per m^3 is?......
.....because it's my understanding that in Canada (and I think also in the U.S.) "acceptable air quality" standards are based on this ug/m^3 calculation.... from a Toronto Star article Jan. 29/08 I understand that Environment Canada's acceptable air quality sets a limit of fine particulate matter of 30 ug/m^3....I'm not sure but I believe Environment Canada using PM 2.5 or the particulate size of 2.5 micron for this standard.....

I haven't seen an 'accepted' conversion but it is possible to convert from particle density (which the meter reads) to a mass density by making some assumptions. For 2.5 µm particles made from wood with a density of 530kg/m^3 a particle count of 10,000 particles/cu-ft (meter reading of 100) would correspond to a mass density of 1.5 µg/m^3 or .015 mg/m^3.

I'm not sure how applicable these air quality standards are as I believe they are dealing with considerably finer particles than we generate in the shop.

While the respirable particles you find in smog may affect lung function most of the dust generated in the shop is compriesed of larger size particles >10 µm in size. Most of these particles are inhalable but get trapped before they get to your lungs. They are also the ones that cause increased cancer rates amongst woodworkers.

Michael - do you have any indoor or outdoor readings to share?

thanks,

Greg

Wilbur Pan

02-16-2008, 9:06 PM

How much does it matter what the composition is? Is, say, clay dust better than maple dust better than cocobolo dust better than asbestos? Is there a hierarchy, and what factors govern how bad different materials of the same size are?

I don't think that anyone knows why one type of dust is worse than others, except that things that are made of tough stuff that your body can't easily break down, such as silica, asbestos, or cellulose, or are of a shape that doesn't lend itself to being consumed, such as asbestos again because it's long and pointy, seem to be worse.

P.S. Can we go back to calling Dr. Pan, Wilbur?:D Otherwise we open the floodgates and will soon be using Sir, Professor, Commander, Your Highness, etc...

Yes, please. If I'm giving chemotherapy to your kid, then you can call me Dr. Pan. ;) Here, I'm Wilbur, amateur woodworker. Emphasis on the amateur. Actually a better title would be, "Converter of Quality Cherry to Sawdust".

Wilbur, fabulous post, thank you for such a clear concise explanation.

So 1 micron and smaller particles, we have no built-in defenses system for, other than inflammation. Easily understood. But are you saying, these particles pass through the thin delicate membrane to our blood? Or do they simply remain lodged in the delicate membrane, causing constant inflammatory response?

I assume only gases can pass through the lung/blood membranes? Or maybe, if the particles are small enough, they too can pass through to the blood?

In a nutshell, yes. Once those small particles get down there, it's exceedingly difficult to get them out, and the inflammatory response just keeps going. Only gases get into the blood, and it's a good thing, because if 1 micron particles got into your blood stream, you'd have to worry about mini-strokes as they floated up to the blood vessels in your brain.

Air that is highly saturated with water vapor, such as a steam room, contains the smallest size water vapor particles as well. Therefore, I would assume a steam room still represent a good therapy to keep these small dust particles from remaining embedded in the tissue...as a much of the water vapor in in the steam will condense in all areas of the lungs, providing a "washing out" of the small particles - which we have no built-in defense against. I recently read something to this in a book on steam therapy. Your thoughts?

Unfortunately, that won't work. Steam or water vapor, once it gets down to very small particles, is just humidity. Besides, in the small airways of the lung, the air there already has a high humidity since it's surrounded by lung tissue, which is already wet. If there is a 1 micron wood dust particle lodged in a small airway, and you get 1 micron water droplets down there, it might become more wet, but it won't be any nearer to getting out of the lung. Remember, in this part of the respiratory tract, there isn't any cilia to clear foreign matter out, so the only way to clear foreign substances is by destruction or absorption by inflammatory processes, which in the case of asbestos or wood dust is difficult because of the nature of the materials involved.

If this worked, asbestosis would be curable by steam baths. As far as I know, there isn't even a case report of this.

John Stevens

02-16-2008, 11:08 PM

While the respirable particles you find in smog may affect lung function most of the dust generated in the shop is compriesed of larger size particles >10 µm in size. Most of these particles are inhalable but get trapped before they get to your lungs. They are also the ones that cause increased cancer rates amongst woodworkers.

Hi, Greg. Would you mind elaborating a little about what you know about this and how you learned it? If I understand your post correctly, this is why I asked earlier about respirable vs non-respirable particles: I've seen nasal cancer listed as a risk of exposure to wood dust, and I was wondering if non-respirable particles could contribute to this risk.

Regards,

John

Bob Antoniewicz

02-17-2008, 1:34 AM

I haven't seen an 'accepted' conversion but it is possible to convert from particle density (which the meter reads) to a mass density by making some assumptions. For 2.5 µm particles made from wood with a density of 530kg/m^3 a particle count of 10,000 particles/cu-ft (meter reading of 100) would correspond to a mass density of 1.5 µg/m^3 or .015 mg/m^3.

Based on the above assumption, 1 particle would weigh:

530x10^3 x (2.5x10^-6)^3 = 8.3x10^-12 grams or 8.3x10^-6 micrograms

so a machine reading of 100 (= 10000 particles per cuft) translates to:

10000 x 36.8 x 8.3x10^-6 = 2.988 ug/m^3

And for anyone wanting a single conversion factor from machine reading to ug/m^3 :

36.8 x 8.3x10^-6 x 100 = .02988 ug/m^3 per machine count for the 2.5um particles.

For the 1 um particles the conversion is (1/2.5)^3 so:
(1/2.5)^3 x .02988 = .001912 ug/m^3 per particle per machine count

For the 5 um particles the conversion factor is (5/2.5)^3 so:
(5/2.5)^3 x 0.2988 = .239 ug/m^3 per particle per machine count

Bob A.

(YIKES!!! That means Greg's initial post reading of 6048/1941 (which as I understand it means the count of 4107 1um particles and 1941 5um particles) translates to 7.8 ug/m^3 of 1um particles and 464ug/m^3 of 5um particles!)

EDIT:

I was trying to remember what folks had said was allowable exposure. I searched and found the following page:
http://www.collinswood.com/M1_WoodProducts/Resources/MSDS_Wood_Dust.pdf
which gives several numbers. The most conservative is 1 milligram/m^3 averaged over 8 hours for total dust from selected hardwood. There is also a 1mg/m^3 averaged over 8 hours for respirable dust (no particular wood mentioned).

So, maybe Greg isn't in real big trouble, but he only cut 23 14" strips of 1" fir.

Greg Funk

02-17-2008, 1:52 AM

Based on the above assumption, 1 particle would weigh:

530x10^3 x (2.5x10^-6)^3 = 8.3x10^-12 grams or 8.3x10^-6 micrograms

so a machine reading of 100 (= 10000 particles per cuft) translates to:

10000 x 36.8 x 8.3x10^-6 = 2.988 ug/m^3

Bob,

My numbers were similar to yours but I assumed the particles were spherical rather than cubic.

Also, it is difficult to convert the larger particle counts to a mass density since the meter doesn't just count 5um particles but particles 5um and larger. So if the average diameter of particles was 20um that would give you a higher mass density than assuming the particles were 5um.

Greg

Bob Antoniewicz

02-17-2008, 2:06 AM

Bob,

My numbers were similar to yours but I assumed the particles were spherical rather than cubic.

Also, it is difficult to convert the larger particle counts to a mass density since the meter doesn't just count 5um particles but particles 5um and larger. So if the average diameter of particles was 20um that would give you a higher mass density than assuming the particles were 5um.

Greg

You know, I thought that might be the case, but when I started typing and tapping the calculator, that totally left my mind. The other thing I was thinking is that the shape of the particle may not be solid, but curled shavings, etc. Or the machine might be measuring a splinter shaped particle by it's greatest dimension.

Also, I remember someone saying way back that below a certain size, any dust you inhale just blows back out again. But I don't know if that was vetted in any sense.

Bob A.

PS - I am really enjoying this thread - Thanks!

John Stevens

02-17-2008, 8:12 AM

I was trying to remember what folks had said was allowable exposure.

Hi, Bob. You'll find some links in my first or second post on this thread, but keep in mind that just because a certain level of exposure is permitted doesn't necessarily mean it's harmless, as Wilbur has written from time to time. One of the problems we face, no matter what the OSHA levels are, is trying to make a good decision in deciding what our own exposure should be, assuming we can measure it accurately. For example, assuming this source is correct, even among white male smokers in the U.S., there's only an 8% chance of dying of lung cancer, if I understand this article:

http://www.journaloftheoretics.com/Editorials/Vol-1/e1-4.htm

I'd like to find out if there's any way of making an apples-to-apples comparison between the lifetime risk of death from cancer of the respiratory tract for lifelong smokers versus career workers in, say, a sawmill or a cabinet shop. Another comparison that could put the "wood-dust-risk" in perspective might be the lifetime risk of death or disability from illness caused by exposure to airborne wood dust for U.S. sawmill workers or cabinet makers vs lifetime risk of death or disability in the total U.S. population due to being involved in a motor vehicle accident while driving or riding as a passenger. Perhaps any attempt at making such a comparison would be so loaded with assumptions that it might be useless, but maybe not.

I haven't been able to find any data comparing rates of diseases like lung cancer, nasal cancer and emphysema in the general population vs persons who have spent a career working in occupations that expose them to high levels of wood dust. Such a comparison would be interesting, although it might overstate the risk for woodworkers who are non-smokers. If I understand what I've read about asbestos and lung cancer, smoking has a synergistic effect, such that the rates of lung cancer among smokers exposed to asbestos is higher than if you were to simply add the rate of cancer for smokers in the general population to the rates of cancer for non-smokers who are exposed to similar levels of asbestos. If the same holds true for persons exposed to wood dust, then the risk of lung cancer from occupational exposure to wood dust for non smokers would be lower than the risk of lung cancer from all persons whose occupations exposed them to wood dust. I suspect that persons in occupations that expose them to wood dust are more likely than the general population to smoke. If correct, I think that that would further increase the difference in rates of cancer between all persons whose occupations exposed them to wood dust and non-smokers who are exposed to similar levels of wood dust wood dust.

Or perhaps I've just had too much coffee and not enough sleep. I'd appreciate feedback from anyone who's tried to understand my ramblings.

Regards,

John

Will Blick

02-17-2008, 11:02 AM

John, I sure appreciate your desire to get a better grip on this wood dust problem...... more specifically, how it relates to the big picture, i.e. those who smoke, live in smog filled cities, etc. It would be a very interesting exercise.

My initial guess is.... it would be impossible to get the data required to do such a calc. For example, for ww's who have had extreme dust exposure for many years, which caused severe respiratory illness till the end of their life....but yet, the person died from a heart attack, which could have been the result of complications from the respiratory illness.... well, this person would defy the statistic.

My suspicion is, these respiratory illnesses can destroy the quality of life for many years, and yet a persons cause of death will often be listed as something else. Probably because our lungs are so over-designed, they rarely become the final weak link in the chain of death. (just speculating here)

One interesting bit of data is....the life expectancy of those who live in the Los Angeles smog most of their lives. I would have suspected with such elevated smog and particulate levels, life expectancy would be much lower than those who live in clean cities. But from what I have read through the years, at best, this life-long smog exposure will only reduce life span 2 years. Its interesting, that people who exercise the prescribed amount, vs. those who do not exercise at all, will only add two years to their lifespan. Of course, this is just theoretical equations trying to pull together all the factors.... I question if they got it right.

Another interesting factor regarding this is.......those who live with constant exposure to radiation. For example, japan has kept meticulous records of the nuclear exposure from the two bombings. Interestingly enough, the people who survived the blast might have had on going health problems, but in the end, they lived several years longer than Japanese people of the same class, gender, social class, etc. A very startling statistic. 1945 was 60+ years ago....those who were 30 then, are 90 now.

In the high elevation of the rockies here in the USA, people are exposed to every high levels of radiation vs. people living near sea level. Most of the radiation from the Rockies comes from the radioactive rock itself.....in addition, at such altitude the suns radiation is much higher... I can't recall the exact numbers, but the difference is quite staggering. Lifelong exposure to such radiation would suggest shorter lifespans, but yet again, the opposite is true.

Also, with smoking, many of the carcinogens are in a gaseous state, which will enter into the blood, unlike wood dust. So smoking IMO is not a good apples to apples comparison, as it relates to particle levels.

Using my Dylos, I am really starting to see where the dust hazards lie. IMO, carpeting might be a bigger dust hazard than ww, at least for the hobbiest who don't spend 50 hours a week in the shop. From my initial experiments, the rooms I have plush carpeting has very high particle counts vs. those rooms with wooden floors. The areas are isolated, so I can get a good read.... I would suggest a 8x increase in particle count on average. Vaccuum cleaners seem to be the culprit.... a beater brush on a vacuum will continually produce micron and sub micron particles.... very similar to sanding wood.... in addition, the suction is pulling all the settled micron particles out of the carpeting.... then, with a very poor vacuum filtration filters, these small micron particles are dispersed back in the air. Combine this with the interesting fact stated earlier in this thread is.... these small micron particles take a long time to settle, from days to weeks. So by vacuuming once a week or every two weeks, we assure a continuous supply of small micron particles will remain airborne in our living environments - sort of, a perfect storm. Many of us breathe our house air more than any other air in our lives. I was shocked to see my house values 5x higher than my shop (at rest), which is not ultra clean to begin with.

I have been investigating true HEPA vacuum cleaners, but this entire field of vacuum cleaners is so scammed based, it's hard to get reliable information. One unit in particular seems to have addressed the problem with a large HEPA filter on the exhaust. But, can't find any independent non biased test results. AS with most new areas of research, we generate more questions than answers :-( Ok, now I am the one rambling on....

John Stevens

02-17-2008, 11:15 AM

One interesting bit of data is....the life expectancy of those who live in the Los Angeles smog most of their lives. I would have suspected with such elevated smog and particulate levels, life expectancy would be much lower than those who live in clean cities. But from what I have read through the years, at best, this life-long smog exposure will only reduce life span 2 years. Its interesting, that people who exercise the prescribed amount, vs. those who do not exercise at all, will only add two years to their lifespan.

Will, with that in mind, here are a few selected paragraphs from something I read recently:

Healthy Aging Health Center

It’s Never Too Late to Live Healthily
Even After Age 70, Healthy Habits Pay Off by Helping
You Live Longer

By Jennifer Warner
WebMD Medical News
Reviewed by Louise Chang, MD

In the first study, published in the Archives of
Internal Medicine, researchers followed 2,357 men who
were part of the Physicians' Health Study. The men
were evaluated when they started the study at about
age 72 and were surveyed at least once a year for the
next two decades.

Overall, 970 men survived to age 90 or beyond.
Researcher Laurel B. Yates, MD, MPH, of Brigham and
Women's Hospital, and colleagues estimated that a
70-year-old man who did not smoke, had normal blood
pressure and weight, no diabetes, and exercised two to
four times a week had a 54% chance of living to age
90.

But for each of these common health risk factors, the
chances of living to age 90 were reduced as follows:
• Sedentary lifestyle, 44%
• High blood pressure, 36%
• Obesity, 26%
• Smoking, 22%
Having three of these risk factors drastically reduced
the odds of surviving to age 90 to 14%, and having
five risk factors dropped the chance to just 4%.

Interestingly, it seems as if a smoker reaches age 70 but exercises and avoids obesity and medicates for high blood pressure, his chance of living to 90 is only 22% less than a non-smoker with otherwise-equivalent risk factors.

As for quality of life, the article continued:

In the second study, Dellara F. Terry, MD, MPH, of the
Boston University School of Medicine and Boston
Medical Center, and colleagues studied 523 women and
216 men aged 97 or older.
Researchers split the participants into two groups
based on gender and the age they developed diseases,
such as heart disease, diabetes, high blood pressure,
dementia, stroke, chronic obstructive pulmonary
disease (COPD), osteoporosis, and Parkinson's disease.

If they developed disease at age 85 or older, they
were considered "delayers," and those who developed
disease at a younger age were called "survivors."

The results showed that 32% were survivors and 68%
were delayers. But researchers found that those who
developed heart disease or high blood pressure before
age 85 and still survived to 100 had similar levels of
function as those who developed disease later.

Food for thought?

Regards,

John

John Newell

02-17-2008, 11:19 AM

I don't think that anyone knows why one type of dust is worse than others, except that things that are made of tough stuff that your body can't easily break down, such as silica, asbestos, or cellulose, or are of a shape that doesn't lend itself to being consumed, such as asbestos again because it's long and pointy, seem to be worse.

Thanks - do we know what makes tropical hardwoods (or some of them) toxic? Presumably something wholly apart from the size of the sawdust particles?

One interesting bit of data is....the life expectancy of those who live in the Los Angeles smog most of their lives. I would have suspected with such elevated smog and particulate levels, life expectancy would be much lower than those who live in clean cities. But from what I have read through the years, at best, this life-long smog exposure will only reduce life span 2 years. Its interesting, that people who exercise the prescribed amount, vs. those who do not exercise at all, will only add two years to their lifespan. Of course, this is just theoretical equations trying to pull together all the factors.... I question if they got it right.

Using my Dylos, I am really starting to see where the dust hazards lie. IMO, carpeting might be a bigger dust hazard than ww, at least for the hobbiest who don't spend 50 hours a week in the shop.

Jogging in NYC or LA always puzzled me...:D :( ...I hear you on the vacs, but I wonder if the stuff that lurks and recirculates is as bad as wood dust?

Then again, look at the nationwide epidemic (I use the term loosely in the presence of MDs) of asthma. When I was in school in the 60s and 70s I never knew anyone with the disease. The number of kids in my boys' classes with the disease is truly shocking.

John Stevens

02-17-2008, 11:24 AM

My initial guess is.... it would be impossible to get the data required to do such a calc.

Will, I have no expertise in the areas of industrial hygiene, medicine, public health, actuarial science or statistics. But I'm sure that data exists regarding the rates of various cancers in the general population and in various occupational groups that are exposed to airborne wood dust. After all, the "permissible exposure levels" established by OSHA and recommended by NIOSH and ACGIH are based upon models that attempt to reach certain projected rates of such illnesses in these occupational groups. I'm not sure how those projected rates compare with the rates for the general population--I assume the projected rates are higher, but I don't know this for sure. I do know that they're modeled on assumptions like no more than 10 hours' exposure per day and 40 hours exposure per week, and, IIRC, a 40 year career. I know there was some debate on how the model should handle the additional risk caused by smoking, but I don't know what decisions were made by OSHA, NIOSH and ACGIH, respectively, in reaching their final sets of assumptions.

A comparison of these rates of illnesses (actual and projected) could be interesting, although I'm not sure how you'd look at factors such as particle levels, particle sizes, hours per day, hours per week, and lifetime hours exposure of, say, a career sawmill employee, and then try to compare that to a hypothetical hobbyist who is exposed to different levels of all of those factors.

Regards,

John

Will Blick

02-17-2008, 11:56 AM

JohnS.... interesting article indeed.... From what I gather, it all comes down to the critical risk factors, i.e., the ones that are most closely related to being fatal. I often thought, many who smoke, don't over-eat due to the appetite suppression the nicotine causes. Its possible the smoking is less fatal than the potential obesity brought on by ceasing to smoke. I am not suggesting smoking is a health tonic.... but I think obesity could possibly be more lethal over many years. Of course, some common sense must come into play...if you need to smoke 4 packs a day to cut appetite, its probably counter productive....but if you smoke 10 cigs a day, maybe then, the obesity avoidance becomes more beneficial.

Of course the article you posted discusses people who have already made it to a certain age (70).... lots of men never make it to this age. It stands to reason if you made it this far, there is a good chance the deck is stacked in your favor.

John N, there does seem to be a lot of mystery about why some woods produce more toxic dust than others.... i.e., its not just particle size here.... I too wish there was more data available....but from the data we do have, there seems to be some woods that have proven to be more toxic than others through experience. then factor in how different we all react to allergens, and it can be a bit of a crap shoot. IMO, I will wear a respiratory, and continue to move air, while watching my Dylos.... if I can eliminate 95% of the problem, I will be better off.... and at this level of reduction, if I react to a given wood noticeably, its time to stop using that wood. However, the wild card here is those woods that are sesnitizers, which make you sensitive to woods you previously were not sensitive too. Jims story about his locksmith in a previous thread sure drove this point home. So being cautious is prudent IMO. But then again, I am one of those people who already have a lot of sensitivities. I see others who seem to be immune to whatever to thrown at them.

> Jogging in NYC or LA always puzzled me

yeah.... when living in LA, I really began to notice the effects of smog, while jogging on smoggy days, I really noticed severe asthma type reactions, which I NEVER had in my life, and was always very physically fit.... of course, I monitored air quality before exercising after these experiences. But, I wonder how much better the air quality is inside health clubs, which ultimately get their air from the outside...then often the added dust from people, carpets, etc. And I agree with the asthma epidemic of kids today.... obviously, we are passing thresholds of what the body can handle vs. when we were younger.

> But I'm sure that data exists regarding the rates of various cancers in the general population and in various occupational groups that are exposed to airborne wood dust.

this is very possible.... but my point was.... if cancer was predominate outcome of wood dust exposure, then I would agree.... this certainly was the case with asbestos....but not so sure its true with wood dust, specially for the hobbiest vs. the lifelong mill worker.

All in all.... this topic has really introduced a health variable I have completely overlooked in my life.... as mentioned previously, because we don't see it, its easy to dismiss it as a health risk. If micron particle wood dust casted a fluorescent glow at all times, many of us would have been suspicious long ago of its potential risks. The Dylos makes these particles visible, so once again Kudos to Phil for bringing this to light, and working the deal that got many members to buy the meter. I think we will all learn a lot in the months ahead with this tool....

Will Blick

02-17-2008, 12:40 PM

Back to Dylos readings....

I was quite surprised to learn how closely my house readings are effected by outside air quality. When the winds kick up here in the desert, my indoor readings have measured very high.... as the winds die down, and the air quality improves outside, such as 2k to 200 readings, the indoor air in my house tracks it. Of course it makes perfect sense, as our indoor air in our house all comes from outside. Just using bathroom / kitchen exhaust fans alone can provide many air changes over a few days, assuming you actually exhaust outside. Then, opening and closing doors, heat / AC systems that have automatic small % outdoor intakes, etc. etc.

Is there a web site that shows avg particle count of cities in the USA?

Greg Funk

02-17-2008, 1:03 PM

Hi, Greg. Would you mind elaborating a little about what you know about this and how you learned it? If I understand your post correctly, this is why I asked earlier about respirable vs non-respirable particles: I've seen nasal cancer listed as a risk of exposure to wood dust, and I was wondering if non-respirable particles could contribute to this risk.

Regards,

John
John,

I've looked at a few papers on the effects of exposure to wood dust but a reasonable summary can be found in a paper, "Report on Carcinogens Background Document for Wood Dust", cited by Wilbur earlier in this thread. The quotes below are all taken from that paper.

Pertaining to Cancer it would seem most of the risk is related to the sinuses and nasal area.

"Adenocarcinoma of the nasal cavities and paranasal sinuses is clearly associated with exposure to hardwood dust"

"These studies consistently indicate that occupational exposure to wood dust is causally related to adenocarcinoma of the nasal cavities and paranasal sinuses."

The larger dust particles are the ones trapped in the nasal cavity hence I assume that it is these particles primarily responsible for the cancer.

"The sizes of wood dust particles vary depending on the type of wood and particular woodworking operation (e.g., sawing or sanding). In general, most woodworking operations produce mainly particles > 10 μm and relatively low concentrations of respirable dust (< 5 μm); therefore, substantial amounts are deposited in the nasal cavity (Nylander and Dement 1993)."

"Wood dust particles are deposited primarily in two areas in the nasal cavity: (1) a small, oval-shaped area at the lower anterior part of the nasal septum near the floor of the nose and (2) the lower anterior end of the middle turbinate (Nylander and Dement 1993). Several studies have shown lower mucociliary transport (clearance) rates in workers exposed to wood dust than in a control group. Decreased clearance rates from the nasopharyngeal region in workers were concentration dependent, and in some cases, clearance took at least two days after exposure had ceased (IARC 1995)."

The smaller respirable particles which make it down into the lungs don't appear to increase your risk for cancer although they could certainly cause other types of disease or impairment.

"Studies of the association between exposure to wood dust and cancers of the oropharynx, hypopharynx, lung, lymphatic and haematopoietic systems, stomach, colon or rectum individually gave null or low risk estimates, gave inconsistent results across studies, and did not analyse exposure–response relationships."

"In view of the overall lack of consistent findings, there is no indication that occupational exposure to wood dust has a causal role in cancers of the oropharynx, hypopharynx, lung, lymphatic and haematopoietic systems, stomach, colon or rectum."

Greg

michael osadchuk

02-17-2008, 1:23 PM

first, thanks to greg and bob a. (and any others) for their calculations on converting Dylos monitor readings to the micrograms per cubic meter (ug per m^3) scale that governments use to measure air quality; your examples seem generally to be in what I sense to be "in the ball park".

here is some readings on a Dylos 1/5 monitor yesterday afternoon at my home and workshop just north of Toronto, Ontario:

outdoors: 70/5

indoors "living quarters": 52/4

basement workshop is environmentally separated from living quarters (house has electric baseboard heating, no "air conditioning", no central heating or associated ducting);
workshop is 20' by 25' approx.
has one 2 speed/3 filter air cleaner hung from ceiling (600cfm?),
a 2 hp General Internationale dust collector with 2 micron bag on top (use it basically only with jointer and planer for "chip collection" by 'temporary" flexible ducting so far)

so, upon entering the shop after overnight absence:

initial reading of 110/8

the day before I had emptied the plastic chip bag from the dust collector; and yesterday, after stirring up dust involved in reattaching the emptied bag to the dust collector, with the monitor about 15 feet away from the dust collector, the reading went to
420/100

after running the air cleaner for a half hour at higher speed, and no other human activity, reading was
80/1

turning on the dust collector (you know, tesing out the little 'puff' of dust that is shaken off the upper cloth bag), reading:
300/100,
then, with the air filter on, reading continues up to
2200/550 five minutes later
coming down about an hour later
to 130/15

used cabinet tablesaw with zero insert, Forrest 2 blade to make about 5 cross cuts on a spruce '2x4', with monitor about 10 feet away, at a 45 degree angle to ts blade plane, with no chip collection, air filter on high, no overarm guard (smiley), reading jumped to:
1200/450
two minutes later up to 3000/1000
ten minutes down to 1000/200
(then called away)

my thoughts:

from bob b.'s low readings (150/25) after using table saw with two points of dust collection and my experience above, having dust collection at source seems very promising to keep down small particulate counts during machining operations

need to repeat above, without turning on the air filter, to compare readings .... does turning on an air filter initially increase readings by 'stirring up' small particulates that might otherwise settle (would likely still use air cleaner to eventually trap small particulates generated)

some, more general comments:

I recall reading on bill prenz's website the statement that
workers in woodworking shops are exposed to lower particulate counts because in those setting dust collectors/cyclones are almost always vented to outside, while amateur woodworkers typically recirculate air exhausted from dust collectors within the shop...... I will seriously consider this option of external venting (I can do it in my locale, don't have central combustion heating/fireplaces, and even the heat loss in winter thru use of a dust collector limited to machining operations is, imho, an acceptable cost vs. the likely air quality gain)

... the comment about respiratory disease possibly not being a "big killer".... a few years ago i read a book by a doctor with the catchy title of "How We Die", and I recall lung failure being right up there in the top five along with cancer, heart, suicide/violence, etc., as what we die from ultimately, ......

... not surprised about the observation that carpets - or the walking on them - stir up particulate pollution..... even a 'messy' house with hard flooring would have the dust settle into the corners, 'safely' away from the usual walkways within a house (smiley)

.... I agree with others that the monitor will help us - including people who learn from others who have the monitor - to 'fine tune' their individual situations with specific solutions and to be more aware of the 'acceptable' risks we are accepting..

thanks

michael

Wilbur Pan

02-17-2008, 3:19 PM

One of the problems we face, no matter what the OSHA levels are, is trying to make a good decision in deciding what our own exposure should be, assuming we can measure it accurately.

This is the crux of the matter. The problem with taking epidemiological data, such as rates of nasopharyngeal cancer among woodworkers, and applying it to an individual, is that you can't do it in a meaningful manner. So much depends on the individual that you are looking at.

For example, suppose that we study a bunch of woodworkers and find that the rate of a visit to an ER for an asthma attack after using the Megatool MarkIV Uberpower random orbital sander is 5 per 100. Does this mean that every time you fire up your ROS, there's a 5% chance of going to the ER? Nope. The only thing this means is that out of 100 woodworkers who used this tool, 5 of them went to the ER. Things that I can think of off the top of my head as to whether YOU will go to the ER or not depends on what your previous asthma history is, whether you have other lung conditions, whether you have pets, what part of the country you live in, how many infections you had as a child, and the list goes on and on.

The only epidemiological study that would truly predict whether I develop lung disease from dust would be if I were cloned into 1000 or so copies of me, expose my clones to wood dust, and see what happens.

The other problem with looking at population rates and applying them to an individual, is that if the individual is affected, the rates don't matter. In my field, I know that the chances of getting a brain tumor when you are a child is 30 per million. Knowing that chance is very low doesn't help the family whose kid has a brain tumor. If you get lung disease from dust exposure, you either have it or you don't.

The only comment I want to make about the only-8%-of-smokers-die-of-lung-cancer article is that if I put a bullet into a revolver, and put that revolver on the table next to a revolver that was empty, and asked you to play Russian roulette, you "only" have an 8% chance of dying (1 out of 12). It still doesn't make playing Russian roulette a smart thing to do.

Thanks - do we know what makes tropical hardwoods (or some of them) toxic? Presumably something wholly apart from the size of the sawdust particles?

I don't know why I didn't think of this before, because I know this -- the oils in tropical woods have a high propensity to to set off your immune system, due to their molecular structure. Also, exotics often contain silica, which goes into the air along with the wood dust, which certainly won't help things.

michael osadchuk

02-17-2008, 5:27 PM

.... my 1/5 Dylos monitor is now actually showing a reading of 48/0 as I watch the Nascar sprint race.....so a zero reading on 5micron scale is either possible ... or an "artifact" :)

michael

Lee DeRaud

02-17-2008, 5:31 PM

.... my 1/5 Dylos monitor is now actually showing a reading of 48/0 as I watch the Nascar sprint race...Oh come on...the race can't possibly suck that bad...:cool:

John Newell

02-17-2008, 8:01 PM

I don't know why I didn't think of this before, because I know this -- the oils in tropical woods have a high propensity to to set off your immune system, due to their molecular structure. Also, exotics often contain silica, which goes into the air along with the wood dust, which certainly won't help things.

IIRC, there was an article in the NYT a few weeks ago about dust being lofted into the air and carried 4k miles away where it is thought to cause asthma and other respiratory problems. I think silica was mentioned, but I believe it also mentioned organics (e.g., animal fecal matter, among others).

John Stevens

02-18-2008, 10:28 AM

The problem with taking epidemiological data, such as rates of nasopharyngeal cancer among woodworkers, and applying it to an individual, is that you can't do it in a meaningful manner. So much depends on the individual that you are looking at.

Right. So what is one to do--assume he or she has an average risk, or the highest risk? If you assume, without knowing, that you're an individual who has the highest risk of an adverse effect, you run the risk that you're unnecessarily depriving yourself of something you enjoy. Hence the smoking analogy. Maybe a better analogy is TS Eliot's excessively risk-averse character, J. Alfred Prufrock, who asked, "Do I dare to eat a peach?"

The only comment I want to make about the only-8%-of-smokers-die-of-lung-cancer article is that if I put a bullet into a revolver, and put that revolver on the table next to a revolver that was empty, and asked you to play Russian roulette, you "only" have an 8% chance of dying (1 out of 12). It still doesn't make playing Russian roulette a smart thing to do.

Right. That's because there's almost no benefit to balance against the risk of the activity. But let's look at another example. My wife is very fair skinned, and she's been told by a number of dermatologists that she has a high risk of developing skin cancer due to exposure to strong sunlight. She was also a gifted middle-distance runner. She had the privilege of competing in a number of international track championships, but in order to get in that kind of shape, she needed to spend about twelve hours a week running outdoors on hot, sunny days in a jogbra and running shorts. She decided the risk of skin cancer was worth the benefit to her. Maybe that was a "Faustian bargain" that she'll regret later if she develops cancer, but maybe not. Her dad died of cancer, so she has an idea of what she's in for. In the meantime, her running career has been one of the most satisfying things in her life. Sort of like what woodworking is for some of us.

Regards,

John

Art Mann

02-18-2008, 1:00 PM

Simple, brilliant analysis!

John Stevens

02-19-2008, 6:43 AM

Simple, brilliant analysis!

Hi, Art. Not sure whether you were referring to something I wrote, or something Wilbur wrote, or something other than the "sorta thread drift" he and I are engaged in. I can't speak for Wilbur, but I think that the problem for both of us, all of us really, is that we're trying to use readings from the Dylos meters to tell us something practical about how to reduce the health risks from airborne wood dust, and in order to help us do so, we have some objective standards, such as the OSHA and NIOSH standards for people exposed to a constant level of dust for up to 10 hours a day, 40 hours a year, over a 40 year period. Unfortunately, we don't know what those standards mean in terms of increased risk of serious illness for the "average" person under those conditions. Do they mean an increase of 0.1% per lifetime? Or 49%? The folks who wrote the OSHA and NIOSH standards know, because by law the standards have to be based upon scientific research and the cost of implementing the standards has to be justified by the results (although there's no objective calculus for the justification). Until we know that, we don't really know what the readings on the Dylos meters mean for the "average" person. But even after we find that out, none of us knows whether we are more or less vulnerable than the average person, as Wilbur points out.

He mentioned in an earlier thread that he wears a mask when he's making sawdust. The price of purchasing the mask and replacement filters is marginal, the inconvenience of wearing the mask while working is marginal, and the benefit could be substantial. Even though he and I seem to differ significantly in terms of risk aversion, I'm giving serious consideration to wearing a mask while making sawdust.

Regards,

John

Will Blick

02-19-2008, 10:26 AM

> Do they mean an increase of 0.1% per lifetime? Or 49%?

John, I know this feeling.... in most fields such as this, where you are forced to make assumptions on top of assumptions due to limited data, often you can't tell if your results are +/-1% or +/- 100%. This is a result of trying to get ahead of the technology curve. Been there, done that, very frustrating...

> I'm giving serious consideration to wearing a mask while making sawdust.

IMO, I think the combination of using Bill Pentz's approaches to dust (where applicable), using the Dylos to confirm whats "really" going on in your shop (and home).... then wearing the mask during high dust producing procedures, overall, you have probably reduced your risk factor by 95%+ vs. not implementing any of the above. IMO, that's the lessons to be learned here.

I personally feel a lot better about how I view high concentrated fine particles of dust. I will also start avoiding outside activities when the particle count gets up into the many 1000's. Wilbur really helped me comprehend, why even nature can throw us a curve ball.... you would think dust in the air is natural, so we would have defenses against it, but that is not the case with the fine particle sizes.... I never paid enough attention to this my entire life, but yet, I always had immediate symptoms such as nasal swelling, shortness of breath, on those very dusty days. Hard to believe it took a ww thread to open my eyes to the reality of dust exposure. I will still engage in ww, but I will be paying much closer attention to generating and controlling dust.

As suggested earlier.... my fear factor now lies more in the wood species, not wood dust in general. It makes sense that all fine dust particles will become irritants to our lungs, forcing an inflammatory response as Wilbur explained. But certain species of wood dust seem to produce more than just an inflammatory response. They seem to be more toxic. Bill Pentz's culprit was cocobollo, a known toxic wood. I have read about other severe and immediate reactions from sassafrases and Walnuts.

Unfortunately, even the science behind, "how toxic is each species" is at its embryonic stage. And it's possible, specific species of wood dust may be as individual as airborne pollens......, some have an immune system which can handle small qnty's of most all pollen with no ill effects, vs. others in which the smallest amounts put our bodies in a crisis state. Even with pollens, there is certain pollen types, such as ragweed, that has a very high allergic rate vs. other pollens. It seems wood dust from certain species is showing signs of following the same pollen pattern.... however, we don't have data from millions of people like the pollen researches have. But from what we have learned, probably much more toxic.

Lee DeRaud

02-19-2008, 10:54 AM

I can't speak for Wilbur, but I think that the problem for both of us, all of us really, is that we're trying to use readings from the Dylos meters to tell us something practical about how to reduce the health risks from airborne wood dust...[snip]Until we know that, we don't really know what the readings on the Dylos meters mean for the "average" person. But even after we find that out, none of us knows whether we are more or less vulnerable than the average person, as Wilbur points out.I'm beginning to believe that the Dylos widget can't do that, mostly due to a complete inability (on our part) to correlate its readings to any standard measurement methodology, or even correlate its readings between two users' shops.

What it can do, assuming some consistency in its application, is provide relative readings to tell each of us whether our dust collection strategy is improving or degrading over time. The real problem is that, given the unit's sensitivity, "over time" requires some really long baselines (like months) and/or multiple units scattered around your house, yard, and shop to factor out all the extraneous things that affect its short-term readings.

Bill Wyko

02-19-2008, 11:51 AM

Greg Funk

02-19-2008, 12:59 PM

It seems wood dust from certain species is showing signs of following the same pollen pattern.... however, we don't have data from millions of people like the pollen researches have. But from what we have learned, probably much more toxic.
You don't need data from anyone to determine if you are allergic to a particular species or wood. Allergists are capable of testing your sensitivity to the wood in question via skin, or preferably, blood tests.

Greg

Art Mann

02-19-2008, 1:38 PM

John,

My comment was directed at your analogy with your wife. I think it is very insightful. Everything in life is a calculated risk. We do things to mitigate those risks, but only to the extent that is feasible. The only way we can guarantee that we suffer no ill effects from woodworking is to stop the activity. Past that, it is a matter of economics and practicality. For example, I wear a good mask during periods of hig risk activity, such as sanding or blowing out the shop with compressed air. If I felt I had to wear a mask at all times, I would give up woodworking because it just isn't worth it. As another example, I have a dust collection system and I am continually working to improve it. However, if I had to spend more on dust collection than on the all my other woodworking tools combined, as some people believe, I would just abandon the activity as being too expensive.

I believe threads such as what this one has morphed into, and Bill Pentz's website, serve to create unwarranted anxiety about the problem far past anything that is reasonable or logical. JMHO.

Chris Padilla

02-19-2008, 4:22 PM

Living is risky! ;)

I bike to/from work every day-->let's talk RISKY! ;)

However, I've dropped 14 lbs. and am in the best shape of my life with 40 staring me down. I've had one wreck (nailed an opposum or racoon as it darted in front of me, hit my tire, I hit the ground: pulled left groin, road rash on left elbow...sidelined for 6 weeks) thus far but I'm practically guaranteed to have a couple more should I keep this up. Believe me, I try to mitigate the risk as much as possible but it is still there.

Phil Thien

02-19-2008, 9:49 PM

Bob Antoniewicz

02-19-2008, 11:11 PM

|My BIL just got his Clearview 5hp dust collector working and all I can say is don't let the pets in the room. It'll suck a cat up from block away.:eek: That thing is a monster. I'm afraid to be in the same room with it.:D

Just got mine. Unpackaged part of it. It is really cool. Can't wait to get it up and running.

I got the Nanofiber cartridges for it. Hopefully it'll work as a general dust remover as well. Will have a lot of work improving capture.

In my line of work there are four categorizations for risk: Known Knowns, Known Unknowns, Unknown Knowns and Unknown Unknowns. This whole topic is an example of the Known Unknowns, i.e. we know there is a risk, but we can't quantify it. In this case we do our best to get to know and understand it (move it to the Known Knowns) or assessing some qualified level of risk and dealing with it the best we can.

Having folks pass along their measurements isn't perfect, but it does give a qualified reference to begin real risk assessment and mitigation planning. I would like to offer again how much I am enjoying this thread, and the thoughtful consideration of it's participants.

Many, many thanks,

Bob A.

PS - My 29 month old daughter has got some kinda bug that is causing her to cough hard and long. Seems to be going around. Can't tell you (though I am sure many of you know from personal experience) how hard listening to that is for me. If my carelessness with dust were to cause something like this or worse -chronic - I might just go and burn my shop down.

Wilbur Pan

02-20-2008, 9:46 AM

Right. So what is one to do--assume he or she has an average risk, or the highest risk? If you assume, without knowing, that you're an individual who has the highest risk of an adverse effect, you run the risk that you're unnecessarily depriving yourself of something you enjoy....

[Russian roulette example snipped]

Right. That's because there's almost no benefit to balance against the risk of the activity. But let's look at another example. My wife is very fair skinned, and she's been told by a number of dermatologists that she has a high risk of developing skin cancer due to exposure to strong sunlight. She was also a gifted middle-distance runner. She had the privilege of competing in a number of international track championships, but in order to get in that kind of shape, she needed to spend about twelve hours a week running outdoors on hot, sunny days in a jogbra and running shorts. She decided the risk of skin cancer was worth the benefit to her. Maybe that was a "Faustian bargain" that she'll regret later if she develops cancer, but maybe not. Her dad died of cancer, so she has an idea of what she's in for. In the meantime, her running career has been one of the most satisfying things in her life. Sort of like what woodworking is for some of us.

I'm sure your wife uses sunscreen. ;)

Not to belabor the point, but I think we both agree that the decision as to how much effort one should put into dust management ultimately comes down to a personal and irrational decision, since there's no good way to quantify risk. Even if you could quantify the risk, one person's 8% is not the same as another's 8%. When I diagnose a kid with leukemia, if the family wants to know survival rates, I tell them that 85% of kids are cured of leukemia. Some families completely lose it at the thought that there's a 15% chance that their kid will die, others are elated that it's only a 15% chance.

This is how I look at it. Woodworking, although it's hugely enjoyable, is a hobby for me. It's a voluntary activity. If I gave myself severe lung disease from a voluntary activity, I would feel really bad if I didn't do what I could to take care of the issue. Even more importantly, if my wife, who seems to be more sensitive to dust issues, developed lung disease, or if one of my kids developed asthma because fine wood dust got up into the rest of the house (I have a basement workshop) from an activity of mine that is ultimately voluntary, that's just inexcusable.

Wilbur Pan

02-20-2008, 9:53 AM

He mentioned in an earlier thread that he wears a mask when he's making sawdust. The price of purchasing the mask and replacement filters is marginal, the inconvenience of wearing the mask while working is marginal, and the benefit could be substantial.

AOSafety QuickLatch Pro. $30 on Amazon when I checked today (and FREE SHIPPING!), comes with P100 filters, and I've worn it while woodturning for up to 3 hours at a time, and the only reason I stopped was that I broke the bowl I was working on. ;)

For the record, the rest of my dust collection system consists of the JDS 1.5 HP dust collector and the JDS 750-ER air cleaner. I did read Bill Pentz's website pretty closely. The reason I don't have a cyclone is that I'm overcoming the CFM issue by having a very short run of flex pipe on my DC, and wheeling the DC to wherever I need it. However, I am maximizing the air cleaner CFM/room volume ratio, since this will filter the air in my small workshop 20-25 times an hour, as opposed to the 6 times an hour most sources recommend.

Total cost: $690 list, and I remember getting it on sale from Woodcraft with free delivery for about $620 to my door. Certainly not a bank breaker in terms of setting up a shop.

Ken Fitzgerald

02-20-2008, 10:07 AM

For some of us woodworking is a hobby....for some a profession. Regardless, like most things in life, it's a matter of risk versus cost/expense. If you can afford a good DC, air filtration system and masks/respirator of sorts by all means do it. If you can't.....well you have to decide on whether the hobby / profession warrants the risk.

It would be interesting to have a study done to determine if "neander" methods produce less small, more dangerous dust particles than more power tool oriented work.

Wilbur Pan

02-20-2008, 10:17 AM

I believe threads such as what this one has morphed into, and Bill Pentz's website, serve to create unwarranted anxiety about the problem far past anything that is reasonable or logical. JMHO.

I think that thinking hard about measures you can take to prevent long term health issues is completely reasonable and logical. JMHO.

If you consider the cost of treating lung disease from wood dust exposure, one admission to the hospital for COPD exacerbation could easily cost more than your entire lifetime woodworking budget.

This is not JMHO.

Chris Padilla

02-20-2008, 10:30 AM

Personally, I got into spending the money, time, and effort on dust collection just because I wanted an overall cleaner environment to work in. And by that, I mean not having to clean up sawdust and track it everywhere. I never really considered the health implications to my lungs. I figure we breathe in all kinds of crap all the time. For the hobbyist, I think all this is overkill as far as lungs go but you know what?! Everyone reacts differently to these things. Bill Pentz and others happen to be more sensitive than some other people. I've known folks in the ww'ing trade who smoke all the time and live in sawdust for all their life and they are fine. Then there are other people who smoke for 5 years and die from lung disease of some kind. It is not easy to correlate all this stuff.

The bottom line is do what you feel you must and what allows you to sleep soundly at night. We all measure that differently and that is OKAY! :)

Cheers

Dan McCallum

02-20-2008, 10:36 PM

Great thread, I have been lurking on it since it started. I received my Dylos meter (.5/2.5) today and have been taking measurements with it. I can see that as more people get their units, borrow them from friends, etc. this post is going to get pretty unwieldy. Maybe the ‘data’ posts get split off from the ‘comment’ posts somehow, as Michael O suggested earlier. Anyways, here is what I have so far. Apologies if it is a bit wordy!

My 150 sq ft shop is in the basement of my house. It has a 1 HP dust collection system that vents outside the house. The floors in the house are all wood, and get vacuumed once a week. There are no carpets anywhere, only a couple area rugs. Heating is via hot water, there is no forced air or filter, or a/c. I also use a neighbour’s detached garage for wood storage and various tasks that I don’t want to do in the house, such as painting.

Readings:
Office, kitchen, bedrooms, living room were all around 1200/40.
Outside (rained a bit earlier today, but had been smoggy yesterday) initially 4300/80
Outside one hour later 2500/45.
Workshop (had been unused for about 18 hours) 1000/20
Vehicle garage 3800/50
Wood storage garage 1500/20
Kids’ school lobby 1500/15
Kids’ school classroom 1200/15
I then took out our vacuum cleaner ran it over the rug in the living room a few times, then left it running for about 5 min. Not previously being intimate with the vacuum cleaner, I was pleased to note it looked reasonably new and stated on it ‘Allergen Filtration. 100% of dust mites and their eggs. 99.5% of ragweed and common grass pollens’. The reading jumped up a bit to 1450/65.
I took a new baseline reading of 2500/45 outside and 900/30 in the shop, then ran a total of 66” of ½” pine through the tablesaw (shop door closed of course!). I had the DC on for the cutting, left it on briefly (15 sec?) afterwards, then turned it off and poked around at my bench. Pretty typical type of operation for me. The meter reading shot up to 2600/800 after about a minute. Lots of big particles, but hardly any more small particles than outside! I could see the numbers gradually dropping, so I left the shop and took a measurement in the adjoining room 850/40. After an hour the shop had dropped to 1100/200. Another hour and it was to 1000/150.
Once the shop had dropped to 1000/150 I then turned on the JDS shop air filter on medium. In 20 minutes I checked back and the reading was 40/1. Wow! I turned it off and then checked back in half an hour, it had drifted back up to 380/10.

Analysis:
Having the .5/.25 meter makes it more difficult to compare against others’ data from their 1/5 units.
However, my readings do seem high, which concerns me. The unit has an ‘Air Quality Chart - .5 um’ on the back, which states readings between 1050 – 3000 are poor. By this chart the outside air at 4300 is ‘Very Poor’! The baseline house readings are pretty similar to the readings at the school though.
I wonder if the high readings in the house are influenced by the high outside readings? Vancouver in the winter does not have a reputation for smog though. Further, I live close to the water where prevailing winds tend to blow any pollution inland. Perhaps as Greg initially surmised, pollen season is gearing up. However, our house is well insulated and sealed, being renovated about 8 years ago.
I do note that my initial small particle outside reading is about 4x my inside reading (4300 vs 1200), whereas Greg Funk observed about a 20x greater particle count outside (650 vs 30). Further, my outside count is more than 6x his outside count, although we live across town from each other. Rich Kelly in Omaha showed 350 vs 120, approximately a 3x difference. Will Blick in Arizona with his .5/2.5 meter had a ratio of about 2.5x.
I also noted that the readings do vary considerably. My initial outside reading was 4300/80, an hour later it was 2500/45. That’s nearly a 50% decrease in a short time for no apparent reason. Similarly the house readings went up from around 1200/40 to 2100/200 in the evening.
Anyways, the fact that the JDS shop air filter took the level down from 1000/150 to 40/1 was amazing.

Next Steps:
I hope to take readings in the houses of a few non-woodworking friends and neigbours. If they show significantly lower readings, then I may be tempted to conclude that the shop is the source of the problem and has caused dust levels to rise in the entire house. Can’t explain the school readings though. If they have similar readings I will be tempted to conclude particulate levels in town are dangerously high!
As a short term measure, I can buy some HEPA air filtration units at the local borg to try and control the levels inside the rest of the house.
I am in the process of replacing my 1 HP DC system with a Clearvue unit anyways. The JDS ceiling mount shop air filter needs to be properly mounted. I just unpacked it today and rested it on the tablesaw in order to note its effect.
Ultimately if I determine that the readings in the house are unsafe and I am unable to bring them down, then I suppose I will have to consider moving my workshop out of the house.

I'd be happy to hear what others think of these results, and I hope I can add more data shortly.

Phil Thien

02-20-2008, 11:57 PM

I'd be happy to hear what others think of these results, and I hope I can add more data shortly.

Well, you asked. :rolleyes:

I think much of the success I've had is due to the electrostatic filter on my furnace, and the vent from the furnace that blows right over the top of the my table saw. While my numbers peak shortly after cutting, they drop pretty quickly, too. And because my furnace's filter is cleaning all the air in the house, my residual #'s are pretty low (although nowhere near 40/1, more like 120/1 or so).

Before getting the Dylos I ordered one of these:
http://www.grizzly.com/products/Shop-Fox-Fine-Air-Filter-/H8184

And I also have one of these:
http://www.amazon.com/Lasko-3900-Performance-Air-Cleaner/dp/B000MF8VLS/ref=sr_1_1?ie=UTF8&s=electronics&qid=1203569549&sr=8-1

Due to the fact that you don't have a forced-air HVAC system, perhaps you can use one of the above filters will help you keep the air in the non-shop areas of the house clean. Of course, now that you're going to use the JDS filter you probably won't have much dust escape the shop. But unless you want to put the JDS in the living quarters of the house for a couple of days, you're probably going to need some way to clean-up the air in the rest of the house.

Finally, with your relatively high outdoor counts, perhaps you can't really do better than you're getting now whether you have a shop indoors or not?

Will Blick

02-20-2008, 11:59 PM

I have been a bit baffled with some of my readings.... my house readings go from 150 to 5000 on the .5 micron scale.

I have two thoughts on this which I am starting to nail down. First, I think no matter how tight you think your house is, it is highly influenced by outside air conditions. My indoor air tracks my outdoor air quite close...not exact, but when outdoor air count goes up to drastically, so does my indoor count. I think this is a result of infiltration through doors, exhaust fans, wind, etc.

Second, I think these meters are highly influenced by humidity, or pre rain conditions. Roger at Dylos somewhat confirmed this. Not sure why....

I am learning, a windy desert is terrible for particle counts.... I have seen outdoor readings go from 200 to 9000 in less than an hour. I am starting to wonder if its safer to stay in my shop :-)

Keep experimenting Dan....

Greg Funk

02-21-2008, 12:22 AM

I do note that my initial small particle outside reading is about 4x my inside reading (4300 vs 1200), whereas Greg Funk observed about a 20x greater particle count outside (650 vs 30). Further, my outside count is more than 6x his outside count, although we live across town from each other. Rich Kelly in Omaha showed 350 vs 120, approximately a 3x difference. Will Blick in Arizona with his .5/2.5 meter had a ratio of about 2.5x.
I also noted that the readings do vary considerably. My initial outside reading was 4300/80, an hour later it was 2500/45. That’s nearly a 50% decrease in a short time for no apparent reason. Similarly the house readings went up from around 1200/40 to 2100/200 in the evening.
Anyways, the fact that the JDS shop air filter took the level down from 1000/150 to 40/1 was amazing.

Dan,

Good to see some more numbers being posted. It is a little difficult to compare with the different meter configurations. I have also noticed a large variation in outdoor readings. The first day I saw 1um readings of 500-600. Since then on a clear day I've seen them under 200. I'm going to leave the meter outside for a day and see what happens. Hopefully it won't be influenced by temperature.

Indoors I've seen as low as 10/0 during the middle of the night when no one is around. Most days it seems to vary between 30 and 100. We have an air-to-air heat exchanger that brings in fresh air through a hepa filter so that may help somewhat.

I'm impressed how well these air cleaners seem to work.

I'm curious how consistent the meters are. If we lined up 5 of them how close would the readings be. Perhaps Dylos will be able to provide some numbers.

Greg

John Newell

02-21-2008, 7:51 AM

Second, I think these meters are highly influenced by humidity, or pre rain conditions. Roger at Dylos somewhat confirmed this. Not sure why....

IIRC, humidity holds the particles in the air longer. Hay fever is usually worse on humid days, other things being equal.

Al Willits

02-21-2008, 8:26 AM

""""""""
What it can do, assuming some consistency in its application, is provide relative readings to tell each of us whether our dust collection strategy is improving or degrading over time. The real problem is that, given the unit's sensitivity, "over time" requires some really long baselines (like months) and/or multiple units scattered around your house, yard, and shop to factor out all the extraneous things that affect its short-term readings.
__________________
""""""""""

Good point Lee, I'm sure the engineers here will spend hours/days/months going over figures and come with enough results to publish a book (maybe a good idea) and some like me will look at all the numbers and wonder what does it all mean?

To me, what it means is this would be a great way to see what's going on in your shop as far as dust and the effects of filtration on it.
It also continues to bring up the matter of keeping your lungs clean enough to enjoy retirement with carrying around a oxygen bottle.

Will I buy one?
Probably not, but what I have done is to buy two 1/2 3M masks and wear then, I leave my DC running a bit longer, and will probably built some sort of hanging filter unit.
Its topics like this that help make woodworking more enjoyable and definitely safer, thanks all.

Al

Brad Shipton

02-21-2008, 12:02 PM

I received mine yesterday. I tried it last night and it helped me find two problems with my cyclone. I got a reading of almost 15000 and after searching out the problem I found a loose bolt holding my filters down and the darn DC had sucked in a piece of chaulking around my lid leaving a small 3/16" hole. I was back down to around 550 this morning.

michael osadchuk

02-21-2008, 3:13 PM

Dan McCallum in Vancouver said:
"Having the .5/.25 meter makes it more difficult to compare against others’ data from their 1/5 units.
However, my readings do seem high, which concerns me. The unit has an ‘Air Quality Chart - .5 um’ on the back, which states readings between 1050 – 3000 are poor. By this chart the outside air at 4300 is ‘Very Poor’! "

Dan, or someone else with a .5/2.5 Dylos monitor, could you post the full air quality small particle count chart on the back of a monitor so calibrated so we can make better comparisons with readings on 1/5 calibrated monitors?

The small particule chart numbers on my 1/5 monitor are:

1000+ very poor
350-1000 poor
100-350 fair
50-100 good
25-100 very good
0-25 excellent

With more background research, in part perhaps on the "typical" distribution of small particles from below .5 mg to 5+ micron, we can make better estimates of what would be the likely readings on particle sizes that our particular calibrated monitor does not sample.

Based on your mentioning that on the .5/2.5 monitor has chart range of 1050-3000 as "poor", if poor ratings on .5/2.5 and 1/5 monitors have the "same" meaning, it would seem that for every 1mg count my 1/5 monitor picks up, I would expect there would be 3 particles under .5mg.
... while the .5 particle counts of around 1200 being rated by Dylos as "good", would suggest that the multiple is more like 10x.
I know my reasoning is very provisional.

...I also note the positive effect of the JDS air filter; it will be interesting to see how its effect changes when turned on earlier after a machining operation, or continuously when in the shop.... does it 'stir up"/keep small particles in the air more until the trapping effect of the air filtration unit does its thing

...regarding the spike up in your shop reading from 900/30 to 2600/800 after some tablesaw use your note "I had the DC on the cutting, left it on briefly afterwards"..... how close was any dust collection pick up point to machining?; I recall Bob B. getting a 'low' reading of 150/25 (on a 1/5mg monitor, I believe) but with two points of chip collection on the tablesaw.....

about buying a HEPA air filtration unit at the local borg for the rest of the house: now that you have air quality monitor you can buy such a air filter unit, without advance reviews, determine how well it actually works and, if it does not measure up, return it, as long as you buy from an outfit (like a 'borg') with a good return policy

btw, I'm satisfied on the costs in this purchase:
fyi, Dylos charged $99.19 u.s. plus 11.86 u.s. postal service = 111.05 u.s;
on my credit card, the billing went thru of Feb. 1st and was converted to $114.21 Cdn. (I believe all the cards add a 2% fee to whatever the currency conversion rate was that day);
the "Canada Border Services Agency" added 4.93 cdn. goods and services tax (gst), 7.98 provincial sales tax (pst) and a 5.00 handling fee (much cheaper than the courier services)
for a total cost of $132.03 Cdn.

Tim Marks

02-21-2008, 5:56 PM

I got a reading of almost 15000 and after searching out the problem I found a loose bolt holding my filters down and the darn DC had sucked in a piece of chaulking around my lid leaving a small 3/16" hole. I was back down to around 550 this morning.
I think your dylos just paid for itself.

Brad Shipton

02-21-2008, 6:40 PM

Tim:
Sure did and now the Clearvue is functioning properly. It is interestings to see how the air is affected. I think it is a wonderful tool to give an indication what is going on with the air I am breathing. Even at 15,000 it still was not bothersome to me nor was the dust visible.

Brad

Lee DeRaud

02-21-2008, 10:36 PM

Dan, or someone else with a .5/2.5 Dylos monitor, could you post the full air quality small particle count chart on the back of a monitor so calibrated so we can make better comparisons with readings on 1/5 calibrated monitors?I've got the 0.5/5.0 unit, but presumably the sticker is the same as the 0.5/2.5 since it only references 'small' counts:

3000+ = Very Poor
1050-3000 = Poor
300-1050 = Fair
150-300 = Good
75-150 = Very Good
0-75 = Excellent

I think the lowest reading I've seen so far is about 110, normal indoor seems to be in the 500-1200 range, with occasional outliers at both ends.

Dan McCallum

03-03-2008, 1:34 AM

I have the same "Air Quality Chart" on my unit as Lee has on his.

For my little test last week where I used the table saw and my readings jumped up to 2600/800, I have a 4" port on the bottom of my TS, nothing above the blade. The Dylos was on the workbench about 5' away.

Have not bought the portable air filtration unit for the house yet. I checked out the Consumer Reports site, they highly recommended a couple units that don't seem to be available locally, I plan to order them in.

I have done further testing with my Dylos unit, and have additional data to share. I would encourage those of you who purchased the Dylos meters through the group buy to add your data as well.

I am extremely impressed with the JDS air filter in the shop. It is capable of quickly reducing the dust levels down to very low levels. Once turned off, levels do tend to drift back up, although not to the same level as the rest of the house.

The new data are summarized below:

............ Feb 20 Feb 22 Feb 23* Feb 24 Mar 1
Outside 4300/80 1300/50 250/50 250/18 800/50
Shop 1000/20 430/10 no data no data 350/15
House 1200/40 590/25 200/50 150/17 650/50

Note that the Feb 23 data were taken at my parent's house, about 3 miles away. It appears that the results change quite dramatically over time, from a high outside of 4300, to a low of 250. An earlier comment was made about susceptibility to airborne moisture, perhaps that is part of the reason here, as Vancouver is typically quite damp and rainy in the winter although the weather over the last few weeks has been more mixed.

I also bought a small compressor and 'blew out my shop' with it a couple of times. I turned on the DC while doing this, as well as opened the shop window and positioned a large fan in it to blow dusty air out. I had to crack the shop door open slightly to allow makeup air to flow in. I was shocked to see the reading jump to 14000 at one point, and up to 4000 each of the other times I did it. I'm hoping to make the dust airborne, and have it either drawn out the window or sucked into the filter.

I've also vacuumed the shop with a vacuum attachment on the DC, as well as removed a lot of the clutter that just seems to gather dust. Removing the clutter sure makes it a lot easier to clean.

I have modified my shop procedures to include turning on the JDS when I go into the shop, and leaving it running on its timer for at least an hour after I leave.

Overall, my alarm levels are down slightly from where they were after my initial readings, but I still believe there is room for improvement.

I will post more data as I have it to post.

Dan

Will Blick

03-03-2008, 11:11 AM

Dan, good findings, good reactions.... this IMO is the purpose of the meter.

A few comments.... yes, i do think these meters are highly sensitive to either humidity or barometric pressure, or both. Before it rains, my numbers jump 10x. Roger at Dylos is suspecting the same thing...it just might be a quirk we need to live with... considering the price of the meter, it's a small compromise IMO.

I also did some further testing..... I will try to summarize to keep the post clear n concise....

In the house... I have determined slow moving ceiling fans can increase particle count on my .5/2.5 unit on avg. about 4 - 5x, quite significant.... I have high ceilings and tried to drive down the heat in the winter at super low speed, but that turned out to be a mistake as it relates to dust....

I bought a Sebo x5 vacuum cleaner, German made, with an amazing triple filtration system. Remarkably, it drastically lowered the particle count in the room it was being used. Whereas my old Hoover upright created a dust hurricane. Quite shocking... the Sebo is tight as a drum, no leaks... of course, this precision engineering comes at a very high price, but considering how they last a life-time, maybe not so bad overall. A great find that the Dylos helped me "see" what was happening...

Shop - I installed a high volume continuous exhaust system operated off an 0-8 hr timer. I blast the dusty areas with some compressed air, or a leaf blower, when I am done...then, leave the exhaust fan on overnight... next morning, readings in the shop are below 150..... about 5x lower than what the shop read when I did not run the exhaust fan over night. Of course, there a lot of variance in this reading due to outside conditions changing, so I am trying to share the readings that are relevant.

For example, if overnight, the winds kick up outside, the reading in the morning can be 800, but this is due to the outside air also reading 800+. Also if it hints at rain the numbers jump.... But when conditions are calm overnight, the improvement is very obvious. One has to pay attention to these variables to make sensible determinations with the Dylos....

Its great news to hear about the effectiveness of the dust filtration systems people are using in their shops. It's nice to know, when exhausting outside is not possible, the air filtration systems can be just as effective.

In the summer, when I run a swamp cooler 24/7, it is another good means to push air continuously out of the work space... I never considered before the value of this constant air replacement....not sure the Dylos will be able to discern any benefits in the summer due to the big changes in humidity....we shall see...

Mike Goetzke

03-03-2008, 12:28 PM

Dan McCallum

03-03-2008, 12:46 PM

Will,

Thanks for the comments.

Although the shop air filter does a good job, I think it is more appropriate to view it as a backup. The reason is that it can only filter out what gets drawn into it - plenty of other dust will settle out into the shop without being filtered. This dust will eventually become airborne again. Thus it would be necessary to have the shop filter on continuously, or more practically all the time you are in the shop.

I guess it gets back to the notion that it is important to capture as much dust as possible at the source, so there is less airborne dust to have to deal with!

Nice to hear that you are blasting the shop with air, as you saw in my previous post I am doing the same thing now also. Thanks also for the tip on Sebo, I had not heard of them before.

Not really sure what a swamp cooler is, some kind of whole house a/c system I imagine? I'm a bit leery of systems that draw the dusty air from the shop, mix it with air from other parts of the house, then filter and blow it out to all parts of the house. I think it'd be safer to avoid mixing dusty shop air and house air to prevent any inadvertent contamination of the rest of the house. I would also think that filtering shop air would dramatically shorten the system's filter's life. Just guessing on this one, as we have hot water heat . . .

What are you using for your exhaust system? I was just going to pick up a bathroom exhaust fan at the borg to maintain a -ve pressure in the shop.

Dan

Will Blick

03-03-2008, 1:14 PM

> Not really sure what a swamp cooler is, some kind of whole house a/c system I imagine? I'm a bit leery of systems that draw the dusty air from the shop, mix it with air from other parts of the house, then filter and blow it out to all parts of the house. I think it'd be safer to avoid mixing dusty shop air and house air to prevent any inadvertent contamination of the rest of the house. I would also think that filtering shop air would dramatically shorten the system's filter's life. Just guessing on this one, as we have hot water heat . . .

A swamp cooler, is a nickname for an Evaporative cooler. In the Southwest, quite common. I use a double evaporative cooler, both direct / indirect coils. It takes 100% outside air, passes the air over each coil and blast the air into the shop.... the shop must have exit areas for the forced air, as its a continuous positive pressure system. Of course, you place the swamp cooler on one end of the shop and exhaust vents at the other end.... this provides continuous fresh air into the shop. Of course, I installed it to drop 110 degree outside air temp. down to 75 degrees, but now realize what a huge boost this AC system is for dust management. I run the swamp cooler about 3 months a year, it keeps my 1400 sq ft garage at 70 - 80 deg. all summer.

When the swamp cooler is not running, I have a 2500 CFM attic exhaust fan which I installed at one end of the shop... it exhaust out the same side as the exhaust from the swamp cooler and the filterless Cyclone, which I also dump outside.

I agree with your assessment regarding the air filters, I certainly was not suggesting they should be the first line of defense. The goal is, get the dust out of the shop when it created...the rest of the measures deals with what is missed...including a respirator when working.

Overall, when possible, I think the Pentz concept of pushing everything outside is optimum. DC system placed outside, whether filterless cyclone, or filtered DC...if the unit is outside, the fine particles that escape the DC filters will be outside.... open doors for cross ventilation when possible, use exhaust fans, etc.

If you have a basement shop, things become more difficult, as you start pulling negative pressures, forcing house air into the basement. But regardless, you use the dust control techniques that work best for your application...hence why I was excited to learn how good the air filtration system works...

Jack Porter

03-03-2008, 11:18 PM

Dan,
I've been making some obervations that seem to be in line with what you have seen. My shop is about 20x12 with a 2hp DC shop built cyclone (wood mag) and hard piped 6" ducting.

I have the .5/2.5 meter, outside readings are typically around 1000/20 and similar inside the house.

Entering the shop readings are around 1200/30 and was used the shop was used extensively yesterday and then blown out (quickly), probably why readings are slightly higher than the rest of the house and outside.

I proceeded to cut about 60lf of 3/4" BB ply, readings went up to about 4500/70. the readings hit this range after about 10lf were cut and stayed constant during cutting. Left the DC running for about 10 minutes and readings dropped down to 1500/40. Shut the DC off and readings climbed back up to around 2000/40.

For what it's worth, I feel comfortable with the DC system as a whole. I can cleary improve the DC at the source, in this situation an overarm DC at the tablesaw and possibly closing in the back of my contractor TS. However, by running the DC after cutting was complete and the quick reduction in particle counts leads me to believe the DC is working well as an air filter also. I am curious what other small shop owners find. More data will help narrow down DC solutions. I'm interested to see what counts are like in the am.

Wayne Watling

03-04-2008, 12:34 PM

Hi,

Mine arrived here in Canada a week or two ago. Before taking the unit into the shop I've been doing some testing in the home environment to try to get some sense of how and what type of environmental factors can effect readings. For instance, mainly in the upper chart you can see the furnace fan turning on and off at regular intervals. This is mainly reflected in the upper graph for particles down to 0.5um, so particles down to 5um aren't as affected by the fan. You can see a huge elevation in the upper chart near the 1297 minute mark where we turned on our Jenair cooktop air intake, this I found to be caused by a leak in the cooktop ducting into the furnace room which subsequently spread the particles throughout the house.
The very large spike seen on the bottom chart (red line) is an unknown at this stage because it occured way before turning on the cooktop unit. Unrelated to the cooktop event there does seem to be some correlation of the two charts in that there is a slow but noticable build up of the smaller particles culminating to a significant rise to just over 2000 (x100 particles per cu/ft) before dropping again at around the 1216 minute mark.

Today I'm sending my unit back to Dylos Corp for them to implement a fix to the small readout screen which would occassionally turn to a ribbon of light instead of a numerical readout (see below) Apparently this can be caused by static electricity and they have verified this in their lab. They will pick up all cost associated with the fix including shipping both ways.

Once I receive the repaired unit I'll do some testing in the shop.

Wayne

These charts represent 30 hours of continuous 1 minute recording within the home environment.

http://i97.photobucket.com/albums/l227/woodworkingpics/Dylos%20Particle%20Counter/Realtimegraph5.jpg

Readout working correctly
http://i97.photobucket.com/albums/l227/woodworkingpics/Dylos%20Particle%20Counter/DataCorectlyDisplayed.jpg

Occassionally the screen turns to a ribbon
http://i97.photobucket.com/albums/l227/woodworkingpics/Dylos%20Particle%20Counter/ErrorNoDataDisplayed.jpg

Mike Goetzke

03-06-2008, 4:49 PM

I too had some fun with my DC1100 .5/2.5 unit in the house. I first placed it in the dining room which is next to the kitchen to keep it out of harms way. As expected particle count is dramatically affected by use of the stove/oven. The first big spike went to 25,000 (x100=2,500,000). I found a couple of burning french fries on the bottom of the oven.

I also added plots of my garage and computer room. My computer room joins the garage/house.

The garage levels really jumped when I used my circular saw a couple of times - even though I have a dust port on it.

I came to the same conclusion that Wayne did when I looked at the computer room results - you can see the furnace cycling.

It's too cold to leave the meter outside in the Chicago area just yet but it was 2000 to 4000 on the .5 to 2.5. It would be nice to have several of these meters so the measurements could be taken at the same time with the same background particle level:

http://img.photobucket.com/albums/v212/mbg/Dust/Garage.jpg
http://img.photobucket.com/albums/v212/mbg/Dust/DiningRoom.jpg
http://img.photobucket.com/albums/v212/mbg/Dust/ComputerRoom.jpg

Next is to use it scientifically in the garage/shop.

Mike

Jack Porter

03-06-2008, 7:19 PM

If you want to see some serious particle count spikes, take some readings after someone takes a shower and then blow dries their hair (no not me, I lack suffient follicles to use a blow drier)

Will Blick

03-06-2008, 11:24 PM

Jack, these meters are ultra sensitive to any water vapor in the air..... it seems, to get sensible relative readings, you must account for the RH in the air when comparing.... this makes the entire comparative process more complex... unless you are doing it over a very short period of time, so you can be confident there is no changes in total moisture content in the air.

Scott Crumpton

03-11-2008, 9:44 PM

Here are a few plots from my .5/2.5 micron unit.

I did the multi-day one just to get a feel for my home office environment. I didn't bother to correlate it with any specific events.

The one labeled "MVS area" is from my office at work. The meter was sitting on the shelf above our laser printer. Quite revealing!

The chart from my shop is self explanatory. Based on discussions here I suspect that the overnight rise in small particles is due to the rise in relative humidity as the shop cooled.

I work at a data center and took the meter into our other office areas and the computer rooms. The offices all looked about the same. The interesting thing was how clean the air was in the computer rooms. Readings were in the 150/6 area. But there is dust on everything. I think the air stays clean because it's constantly filtered by the big AC units. The dust on all the horizontal surfaces comes from the people and opening up the floors to access cables. All large particles that settle out before they can be filtered. It's clear the we need a maid. :)

Ken Ganshirt

03-14-2008, 12:14 AM

I posted this elsewhere a few days ago so I'll just copy it here. It's pretty much self-explanatory but there are a few comments to link it into the thread. I have the 0.5/5 micron unit with computer port.

You won't see any furnace cycling in the house measurements. My furnace has a two-speed fan and runs continuously all year long. I have an electronic air cleaner on the cold air return to the furnace with a reusable electrostatic filter in front for a prefilter.

You will see reinforcement of the impact in the house of showers, cooking and opening the door and allowing infiltration of outside air.

You will see reinforcment of the increase in fine particle counts due to RH from a weather system moving in overnight.

You will also see reinforcement that even a small dust collector with a decent filter on it acts as a passable air cleaner. I have a cheap 1HP King with a 1 micron upper bag and clear plastic lower bag. It pulls the fine particle count down nicely when it's running. Even my 2 1/2" shop vacuum with HEPA filter in it will pull the count down a little as long as the exhause isn't pointed at a dust pile.

It's still too cold here on the Canadian prairies (great plains) to do outdoor readings for correlation purposes.

-------------
Okay, I finally got around to cleaning up the spreadsheets and grabbing the charts. I have a couple from the living room and a couple from the shop.

The first is 24 hours from the living room, starting monitoring at 8:12am.

http://i19.photobucket.com/albums/b152/kganshirt/Dylos%20Charts/Dyloschart03MAR2008812am26hoursLivi.jpg

The early spikes between 1 and 658 are mainly from the front door opening. The one at 74 is someone taking a shower.

The big jump at 658 was preparing supper. There was a break in the reading while I saved the data and fiddled with the spreadsheet for a few minutes at the point where it drops way back just after 804. I'm not sure why the straight drop instead of a gradual decline.

The gradual increase, starting at 1023 is overnight. The only explanation I can think of is that a serious weather system moved in overnight. The spike at 1461 was leaving the house to head for the gym (front door opening). The final spike at 1534 was from taking a shower.

Here is another 12 hours from the living room, starting monitoring at 10:50am.

http://i19.photobucket.com/albums/b152/kganshirt/Dylos%20Charts/Dyloschart04MAR20081050am12hoursLiv.jpg

This one looks much smoother than it really was. That huge spike at 417 was sauteeing onions in the frying pan at supper time. It spiked so high (over 8800) that the scaling on the chart makes the rest of the readings look much smoother than they really were. If I chopped that part of the chart off, you would see bumps throughout the day from the front door opening, showers and other typical daytime activities.

One of the things that would show up much more significantly is when I came in from the shop (235 to 270) and sat in a chair near the unit. It's surprising how much dust comes back in on your clothes and hair, and also how long it persists. I sat near the unit for nearly an hour and the reading stayed up. It didn't start to drop back down until I left the room.

Here is approx. 8 hours in the shop, starting at 4:35pm.

http://i19.photobucket.com/albums/b152/kganshirt/Dylos%20Charts/Dyloschart05MAR20081635pmShop.jpg

I entered the shop and puttered for a few minutes. Fired up the big shop vacuum and cleaned up a bit around the lathe. Then I ran a 10' flex hose extension over to the lathe. I turned on the dust collector at 30. You see the spike and then a steady decline. During that decline I was turning a couple of small spindle items, including some sanding.

The bump in the downslope at 65 was a quick cut on the mitre saw. I turned the dust collector off and left the shop at the 135 mark. The rest was reading in the empty shop. You can see two distinctly different trend lines. In the small particle chart you can see the reading climb. I assume that's the fine dust starting to settle closer to the meter. If I had been sitting in the shop I'm sure I would also be able to identify bumps from the construction heater going on and off.

The trend on the large particle chart is a steady decline. I assume that's also settling, in this case onto flat surfaces where they stay and are not disturbed by the heater fan.

Finally, another 4 hours in the shop, starting at 1:52pm.

http://i19.photobucket.com/albums/b152/kganshirt/Dylos%20Charts/Dyloschart06MAR20081352pmShop.jpg

You can see a bit of a drop in the small particles when I turned the dust collector on at 10. The spike at 15 is a quick cut on the mitre saw followed by rounding off a small bowl blank on the bandsaw. I was turning the small bowl blank then I stopped, turned the dust collector off and left the shop at 109. I came back into the shop at 220 and turned the dust collector on for a few minutes just to see what would happen. Finally I turned the dust collector off and stopped monitoring.

It has mostly been too cold to do any baseline readings outside. The documentation with the meter warns against running it when it's too cold so I haven't.

...ken...

Greg Funk

03-14-2008, 12:25 AM

Great data Ken! Thanks for sharing. How big is your shop?

Greg

Ken Ganshirt

03-14-2008, 1:09 PM

Great data Ken! Thanks for sharing. How big is your shop?

Greg
Hi Greg,

The inside measurements are 17' x 31'. The height averages about 10'. It has a vaulted ceiling (scissor trusses). The peak is 11' and the tops of the walls are 9½'. You can see more of it here (http://gansk.sasktelwebsite.net/new-workshop.htm) if you're interested.

The Dylos was sitting near the centre of the shop about 4' above the floor. I have a bit of a problem in positioning it where I want it. The only serial-to-USB adapter I could find in town is 18" long so I'm restricted to placing it somewhere that both the Dylos and the laptop will sit side by side. I have a 9-pin serial cable but it doesn't work for some reason. I guess I'll have to break down and build one so I can have some more flexibility where I put the particle counter when I'm doing real-time capture with the computer.

...ken...

Greg Funk

03-14-2008, 2:35 PM

Hi Greg,

The inside measurements are 17' x 31'. The height averages about 10'. It has a vaulted ceiling (scissor trusses). The peak is 11' and the tops of the walls are 9½'. You can see more of it here (http://gansk.sasktelwebsite.net/new-workshop.htm) if you're interested.

The Dylos was sitting near the centre of the shop about 4' above the floor. I have a bit of a problem in positioning it where I want it. The only serial-to-USB adapter I could find in town is 18" long so I'm restricted to placing it somewhere that both the Dylos and the laptop will sit side by side. I have a 9-pin serial cable but it doesn't work for some reason. I guess I'll have to break down and build one so I can have some more flexibility where I put the particle counter when I'm doing real-time capture with the computer.

...ken...
Thanks Ken,

It looks like your dust collection is working pretty well for you. Nice shop by the way.

You probably just need a null modem adapter for the serial cable. It will switch the tx and rx signals.

Greg

Ken Ganshirt

03-16-2008, 1:44 PM

It was the Dylos particle counter that spent the day in the shop, not me! I was in and out and did a little bit of sawdust creation. I left the Dylos running the rest of the time to get an idea of settling times and other particle behaviours.

Here's the chart, for 18 hours on March 14.

http://i19.photobucket.com/albums/b152/kganshirt/Dylos%20Charts/Dyloschart14MAR20081347pmShop-1.jpg

I came into the shop, started up the computer and Dylos and puttered for a bit. You can see a bit of a bump at the start as I was moving around and clearing some work space to start a small project (funeral urn for a good friend). Then I get sidetracked and had to leave the shop for a few hours.

I came back into the shop at about 160. You can see the count start to move up as I dug through the wood pile to pick out a good board. The first big spike at around 190 is a couple of crosscuts with the circular saw to break the board down so I could get the short pieces comfortably onto my mitre saw stand. The immediately following big spike at 200 is using the mitre saw to cut the boards to rough length. I have the shop vacuum hooked to the mitre saw but as you can see from the spike, the mitre saw is still messy.

I turned on the dust collector (1HP King with 1 micron upper bag and plastic lower bag) right after the the mitre saw cut. The flex hose was just lying on the floor at that point. I left to do something in the house.
When I came back in the shop at about 220 I connected the DC to the jointer and jointed a straight edge on the boards. Then I connected the DC to the tablesaw and the shop vacuum to the Shark Guard. I ripped the boards to width. Then I moved the DC hose to the jointer and jointed one face of the boards flat. That was a total of a little over five linear feet of 5/4 walnut on each operation.

The ripping was at 230 and the face jointing at 238. This is an interesting result. You can see a slight bump in the steep downward slope at that point, but the dust collector and Shark Guard with shop vacuum seemed to contain things fairly well and so the tablesaw did not make another big spike as I had been expecting it might. The jointer didn't have much impact at all. The counts continue to drop pretty steeply as the dust collector continues to run until 255. That's when I turned off the dust collector.

You can see the flattening of the curve from 255 that shows the settling continues but without the help of the dust collector the count is not dropping as fast.

At 318 I came back in the shop and turned the dust collector on. You can see the curve start to dive down again as the DC does a fairly decent job as an air cleaner. I left the DC running with the flex hose lying open on the floor for an hour and forty-five minutes. When I came back into the shop to turn it off at 430, the fine counts were down to 18. In reviewing the data, the fine count had been down under 100 since 374. So it took about an hour for the dust collector to pull the fine counts down from 650 to under 100.

After turning the DC off at 430, the fine count creeps back up a bit. When I checked an hour and a half later at 512, the count had crept back up to 80. Over the next ten hours overnight the fine count moved back up to 150.

...ken...

michael osadchuk

03-16-2008, 4:03 PM

ken..... interesting data

....regarding your posting today (March 16) some observations:

miter saw and circular saw don't just throw off 'big' particles but lots of .5 and under stuff

dust collection at source seems to be confirmed as a very effective way of preventing readings from going to the "very poor" part of the scale

what I found new/surprising in this data:

even without any dust collector/ambient air filtration running, even the small dust particles - under .5 micron - seem to fall from a very poor rating (+3000) to high end of "fair" (300-1050) within a relatively short (?) period of time........ some of the background reading I had done suggested that particles under .5 stay suspended in the air for days.

..... interesting that a 1 hp dust collector w/ 1 micron bag seems to operate with effect as an ambient air filter

the computer linkage of the Dylos provides some eye-popping documentation

thanks for taking the time to post

michael (who has a 1/5 Dylos monitor)

Ken Ganshirt

03-16-2008, 10:57 PM

Michael,

One correction .. my Dylos is not counting paricles smaller than 0.5 microns. It's counting particles bigger than 0.5 microns. I understand what you are saying about settling times, but I still have no idea what is happening to the stuff smaller than 0.5 microns. I don't know whether it is being reduced in a similar amount or whether it's still a big number. This can be a concern because the stuff at 0.3 microns is supposed to be some of the most worrisome.

It appears that the dust collector is working in a very similar fashion to an air cleaner. That should be no real surprise when we think about it. Even my 1HP with a 10' x 4" flex hose attached should be pulling in 400cfm or better. That's not shabby for an air cleaner. One major difference is that it's exhausting in all directions through the top filter bag so dedicated circulation patterns should not have as good a chance to develop. That's a good thing. Another difference is that most of the air cleaners I've seen come standard with 5 micron filters. My filter bag is supposed to be 1 micron. With the cake it currently has, it appears to be filtering smaller than that.

We can also see from the overnight creep back up that there's still a lot of stuff being held in suspension away from the particle counter that starts to drift back to the counter as soon as the DC is turned off. I'm sure that's because the fan in the counter starts to act like a mini air cleaner without filters. Once the air in the shop is calm, the Dylos starts to "vacuum" any of the fine stuff that is in reach of its fan as it settles out of any suspension patterns the DC created while it was running. Also, the fan in the electric construction heater will keep stirring things up each time it runs.

I think I'm going to start a new thread with my next charts. This one is so long that most people will miss these latest postings. When I came back tonite I couldn't find my latest charts or the later postings. The normal navigation only shows about six pages worth of postings in a thread. You have to know how to get past that to find the rest and it's far from intuitive ... I've never seen anything like it and I've been using bulletin boards and forums for over 25 years!

...ken...