Bill Pentz and Cyclone Test [Archive] - Sawmill Creek Woodworking Community

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Jay Albrandt

10-20-2006, 8:54 PM

I feel like I won the lottery! Bill Pentz came and evaluated my dust collection system and shop today. I can't believe how much time he invested (over 3 hours) and how thorough he was.

He started with an overview of the process, what he was measuring, and why. Next, he inspected all of the transitions to my tools and made many recommendations. Next, he tested the air outside of my shop for an ambient baseline, and then the shop air before running any equipment or the opening of any doors. Next, we fired up the cyclone and tested the air without cutting anything (my filters exhaust inside). The next test was done after cutting a 3 foot long piece of MDF, 18 times. Finally, the last test timed how long it took for the air quality to return to the baseline measurement.

What I learned: (Please keep in mind that I am a layperson and I am trying to process and regurgitate a TON of information).

1. All dust hoods and guards must do two things: They MUST be an effective physical barrier to dust being spewed away from the blade, and thus away from the air collection stream. If you don't have this first, then no matter how much CFM you have at the tool, you simply are not going to catch the harmful dust.

2. There was, is, a significant residual dust problem with my shop....meaning that I haven't been in there for two days prior to the test and there was enough total suspended particles (by weight) that I was almost halfway to requiring a mask, and I had 100,000 more particles in the 0.5 micron range than the outside air! Eeeeek!

3. I learned that my filters do an excellant job of cleaning the air in my shop. By running the cyclone and not cutting anything, the filters reduced the total particles from comment #2 by half.

4. After cutting the MDF, the particulate matter (both in size and weight) doubled to just past the point of requiring a mask for my safety. This means the cyclone and filters are doing their job, but my dust hood needs some improvement.

5. By just opening the garage door, and putting fans in the back door, I reduce my exposure significantly.

6. For those of you who have a Pentz' design cyclone. I have the 14" impeller and my real world, direct measurement came out to be 1,099.564 CFM, with the 5hp Lesson motor at only 10.8 amps. That means I can upgrade to the 15" ClearVue impeller and get another 300 CFM when I expand my shop and still not overload the motor. smirk!

I hope this is helpful.

Jay

Jim O'Dell

10-20-2006, 10:10 PM

Bob Marino

10-20-2006, 10:47 PM

Thanks for sharing and a thanks once again to Bill Pentz.

Bob

Jan Williamson

10-20-2006, 11:07 PM

Jay,
I have the Clearvue, some recycled filters and muffler in a sound board lined closet. I got similar results although your CFM's were little higher that mine. I have a not so ideal duct system (newbie), and some leaks around the blast gates , but still at over 900 CFMs still over what the biggest dust makers need (with proper hoods). I like the idea of having a fan in the back if the garage (on nice days), and blowing out the shop every week or so too. Bill gave me lots of sound advise for improvements. I am extremely satisfied with my system, and feel lucky to be included in Bill's studies.
Did he get any chocolate chip cookies at your place?:D

Jay Albrandt

10-20-2006, 11:17 PM

WOW!!! That is cool!! Makes me wish I lived in California so Bill might visit my shop....Nah. :D
That is a very good test. I like the idea of measuring before you did anything to get the base line, and also to test outside.
You say your filters did a very good job...what filters do you have? I'm thinking seriously about exhausting outside as I don't condition the air in the shop. but there might come a day when I will need to filter it and keep the air inside.
Thanks for the post! Jim.

Jim,

When I say that my filters did a good job, I mean they filtered the residual particulate down below the baseline, but when I cut the MDF, I still had a rise in everything to the point of being unsafe. I'm not the expert, but I don't think I can attribute all that rise just to what I am missing at the blade hood....the filters are still passing stuff. I have the Wynn Environmental filters that Bill recommended at the time I built the cyclone. He said the Torit filters are better, but I couldn't afford them at almost 3x's the cost.

Bill said that with my results, I should try to vent outside and that so far, that has been a common recommendation with a few exceptions. I am really looking forward to his conclusions when he is done testing all these shop. I would like to see how my set-up compares to what others are doing.

Jay

Jay Albrandt

10-20-2006, 11:24 PM

Did he get any chocolate chip cookies at your place?:D[/QUOTE]

Jan,

No cookies!...He wouldn't let me. He did brag about the elk you served though. I offered to have anything on hand for him and of course he politely refused. I mean the guy drives down here all the way from the Sacramento area to test my shop for free, and the only thing he would let me do is buy him lunch?!!!! Wow!

He said you have a beautiful set up.

Jay

J. Scott Chambers

10-20-2006, 11:29 PM

Based on your statements #3,4, and 5 above, I'd say your filters are working, and it's your hoods that need improving. I don't see how venting outdoors will cure that, other than diluting the air with lower particle count OA.

John Renzetti

10-21-2006, 9:11 AM

hi Jay, Thanks for the informative post in a real life situation. MDF can be nasty stuff. If you are going to cut a lot of this stuff then the investment in those .2micron Torit filters would be worthwhile.
take care,
John

Russ Massery

10-21-2006, 9:19 AM

Like Jim I'm envious, Great to know mine has the 15" impeller. Standard now now on all Clearvue's. But like Bill said even the best equiptment doesn't work well with out proper dust hoods. Wish I could have Bill check my system out. :rolleyes: Bill if your ever in the Great midwest. The SWMBO makes great chocolate chip cookes.:D

Bill Pentz

10-21-2006, 9:38 PM

My thanks to Jay and his lovely wife for having me come visit and our nice lunch together. Jay has a shop that he is using to rebuild a home and folks he is not just good, but doing incredible work. If I had a tenth his energy some of my backlogged projects would be getting done.

This last few days was quite an adventure in terms of testing as I managed to log just over 1,100 miles since Thursady and look at a few shops. Without mentioning any names how about a 60x40 shop with tons of refurbished old iron, meaning a 1000+ pound lathe and more? Came home and saw my lonely tools just sitting waitng for me to rebuild ducting, install another cyclone etc. and think I am going to go rest up for a while.

Test results are showing some very consistent things. Those who setup their shops with a regular through airflow (open big door in front and fans in the rear) have no significant buildup of residual dust, but every one who closed the doors had had residual dust problems regardless of dust collector, cyclone, filters, or air cleaner. Evern more imporatnt, every shop I've tested no matter how good the airflow ended up with problems if their hoods did not do a really good job of blocking, trapping, and collecting the dust. Likewise, even with good hoods, those systems that did not move enough air also had problems with very high dust levels following our test cuts. I just cannot emphasize enough that our hoods have to block, control and capture the dust plus we need to move the air and then get rid of that fine dust. The only other issue this testing is showing is the huge numbers of very fine particles that are going through the filters along with a few failed filters that woodworkers thought were working just fine.

bill

Alan Simpson

10-21-2006, 11:46 PM

The only other issue this testing is showing is the huge numbers of very fine particles that are going through the filters

OK now I'm confused... you spent most of your post talking about how the residual dust is caused by insufficient airflow and/or poor dust hood design allowing dusto to escape and never reach the DC.

How do you make the jump from that long-winded explanation to a "huge number of very fine particles" going through filters???

With all of the controversy and accusations about Filter performance of late, I would hope you would go a little deeper into explaining your statement rather than just throwing it out there like you did.

What kind of filters??? Bags? Cartridges??? Rated filters??? What do you consider "Very fine particles"??? What do you consider a "huge" amount??? And probably most importantly, how are you differentiating between dust escaping from the hoods and dust escaping from the filter?

rick fulton

10-22-2006, 12:31 AM

Bill,

Is all this testing leading up to a magazine article?

Or maybe a summary of system / component dust collecting efficiency for your web site?

Or have you won the lottery and now just plan to tour the country in a self financed crusade to protect hobbyist woodworkers from that vermin Lignum Pulvis?

I'm looking forward to your final summary.

rick

Jim O'Dell

10-22-2006, 9:45 AM

Goodness, jump on the guy for doing a little research...I applaud Bill for doing his in house study. It appears to me that he is looking for information. Maybe the recent threads on filters and such prompted it, maybe it was in the works for a while. It also looks like he is talking about things he has found so far, but hasn't made any conclusions yet. He may still need more data, he may just not have had time to crunch the numbers yet. I mean he did say he he drove 1100 miles in 3 days, plus the time setting up at each location, all this on a man who's health isn't perfect to begin with. With lunch (and cookies!) that would have to be about 11 or 12 hours each day> So be thankful he is doing it. Is it a scientific controlled study? No. (Though it sounds like it has some controls. ie: 18 cuts on a three foot long piece of MDF) Is it information that may be useful to us, and to those that recommend the type of equipment and filters that are best? Time will tell. I hope it has some very useful conclusions for all of us.

Until Bill finishes his work, I wait in anticipation of his conclusions. I hope he will publish his findings on his web site, and include the sizes of each of the shops, what kind of saw, what kind of blade, and what type of hood the tool used, along with any modifications made to it. AND THEN, what he would recomend for each of the owners to do about their systems. Jim.

Robert Witter

10-22-2006, 11:35 AM

Bill,

What test procedures and test equipment did you use on Jay’s shop you visited where you reported 100, 000 times more dust in the 0.5 Range.than outside? How did you isloate the 0,5 micron material? This takes some preety sophisticated equipment. Will you publish the actual values?

Are you saying to blow the air outside in this case because the Wynn filters Jay uses are not capturing the fines? I didn’t understand that part

I have always read that wood dust is not particularly small as dusts go. Only a tiny fraction of the airborne wood dust is sub micron.
I will site a wood shop air sampling study from University of Vermont , Burlington VT Dept of Epidemiology and Environmental Health.
They ran 13 different machines: belt sanders, drum sanders, routers, shapers, and various saws classified the airborne dust by size. 22.5, 14.1, 5.5, 3.2, 2.0, 1.2 Microns

For Example:
In 9 tests they recorded zero % of the material was below 1.2 micron in size. On 4 tests the amount of dust below 1.2 micron was one tenth of 1 % of the total air borne material. By weight.

How does this compare with your tests? How are you getting 100s of thousands times more 0.5 micron material?

Also, It looks like the amperage and CFM tests reported by clear vue owners show that they run only about 10.8 Amps @ 230V for 1100 CFM. This is only half the amp rating of a 5 HP motor.
This is well within the limits of a 2HP 11- 12 Amp motor at 1100 CFM. Are these reports correct? If so why are you running a 21 amp 5HP motor to get 1100 CFM and wouldn’t a two or three HP accomplish the same thing?

Sincerely,
Robert Witter

Phil Thien

10-22-2006, 11:46 AM

OK now I'm confused... you spent most of your post talking about how the residual dust is caused by insufficient airflow and/or poor dust hood design allowing dusto to escape and never reach the DC.

How do you make the jump from that long-winded explanation to a "huge number of very fine particles" going through filters???

I think, if the filters are deficient, then the last phase of Bill's test (waiting for a return to safe levels with no cutting but DC running) will take forever or will never happen. It is during this phase that they are essentially using the DC as an air filter, and the suitability of the hood is pretty much out of the equation.

It is possible for the hoods to also be deficient and for that to be detected earlier by the detection of larger particles during the cutting tests. Larger particles suspended in the air would indicate that these particles are getting past the DC altogether.

Alan Simpson

10-22-2006, 11:54 AM

I think, if the filters are deficient, then the last phase of Bill's test (waiting for a return to safe levels with no cutting but DC running) will take forever or will never happen. It is during this phase that they are essentially using the DC as an air filter, and the suitability of the hood is pretty much out of the equation.

It is possible for the hoods to also be deficient and for that to be detected earlier by the detection of larger particles during the cutting tests. Larger particles suspended in the air would indicate that these particles are getting past the DC altogether.

Excellent point Phil. Of all the people who have reported their results of Bill's testing, they all mentioned how quickly their DC returned the air quality to the baseline after cutting ceased (by leaving the DC on). To me, that directly contradicts Bill's claim that "this testing is showing the huge numbers of very fine particles that are going through the filters". As you stated... if this were true, the air quality would NEVER return to the baseline.

:confused: :confused: :confused:

Don Baer

10-22-2006, 11:57 AM

Robert,
I can't speak for the other question because I wasn't with Bill doing the testing but I can speak about the equiptment he is using. It is a GT 531 Particulate counter from Met One Instruments. The reason I know this is because Bill asked me for a recommendation of the types of instrument to use and this is the one I recommended. I met the folks at Met one at the last AIHCE show in Chicago and found that it is just the ticket for doing portable survey work like Bill is doing. If you would like more information feel free to PM me or go to there web site.

Just a side note I don't work for Met one I am just a happy customer.

Phil Thien

10-22-2006, 5:04 PM

Jim O'Dell

10-22-2006, 5:26 PM

Excellent point Phil. Of all the people who have reported their results of Bill's testing, they all mentioned how quickly their DC returned the air quality to the baseline after cutting ceased (by leaving the DC on). To me, that directly contradicts Bill's claim that "this testing is showing the huge numbers of very fine particles that are going through the filters". As you stated... if this were true, the air quality would NEVER return to the baseline.

:confused: :confused: :confused:

Do I gather from your post, then, that you feel the problem is at the point of collection? If so, I think that is a good point. (If not, let me make that point here:D ) I know Bill Pentz devotes a pretty good section of his site to pick up hoods. Other sites touch on it as well. So, who has a good handle on pick up hoods for different types of machines? I'm really amazed that with the prolifferation of cyclones in todays market, that more of the distributors don't push for 5", or prefferably, 6" hook ups on their table saws, jointers, bandsaws, etc. And while there are some aftermarket pick up hoods for mitre saws and contractor saws and such, I don't see manufacturers stepping up and developing these for their specific tools. I'd like to see even adjustable air inlet holes via a slide like a blast gate to adjust for the air flow within a specific tool. (To collect the dust and chips, you need air flow, not suction)This should be easy to do on a TS or Jointer. Properly positioned, it would allow the air to then flow across the Blades(s) and on into the pick up tube for optimum collection.
Anyway, just some thoughts since I'm house bound today. Jim.

John Renzetti

10-23-2006, 8:48 AM

[QUOTE=Robert Witter]Bill,
[

I have always read that wood dust is not particularly small as dusts go. Only a tiny fraction of the airborne wood dust is sub micron.
I will site a wood shop air sampling study from University of Vermont , Burlington VT Dept of Epidemiology and Environmental Health.
They ran 13 different machines: belt sanders, drum sanders, routers, shapers, and various saws classified the airborne dust by size. 22.5, 14.1, 5.5, 3.2, 2.0, 1.2 Microns

For Example:
In 9 tests they recorded zero % of the material was below 1.2 micron in size. On 4 tests the amount of dust below 1.2 micron was one tenth of 1 % of the total air borne material. By weight.

Also, It looks like the amperage and CFM tests reported by clear vue owners show that they run only about 10.8 Amps @ 230V for 1100 CFM. This is only half the amp rating of a 5 HP motor.
This is well within the limits of a 2HP 11- 12 Amp motor at 1100 CFM. Are these reports correct? If so why are you running a 21 amp 5HP motor to get 1100 CFM and wouldn’t a two or three HP accomplish the same thing?

Hi Robert, Good points and information. The tests of dust particle size is interesting. However wouldn't particle size especially the submicron size be determined by the material being processed. I know mdf produces some nasty dust. Also sanding grit would also have an effect on particle size. That's why I feel that the choice of filters should depend on the type of wood processing being done. And of course the individual involved, as some are very sensitive to any microscopic wood dust. I use a dust collector (European) that has a BIA rating of whatever Class C or G. I still use a JDS shop filter and when I feel it necessary I use a mask.

With regard to motor hp/amps draw/cfm, doesn't the amp draw of a motor increase as more blast gates are open. So if the 5hp in the clearview is drawing 10amps, it just means that's all it needs, and it's not working as hard as it could, and has plenty of reserve power. A 2hp motor drawing 11 amps is working a full capacity and if you opened up more than one blast gate you'd be in danger of overheating the motor since the motor will draw the amps demanded. Some motor manufacturers will show in their technical data the power produced at various load demands up to 150%. The motor can produce 150% of its rated power, but it just won't last as long.
Thanks for the great input and for helping to keep this debate/discussion on a lively but not overheated level.
take care,
John

Ed Morgano

10-23-2006, 8:46 PM

lou sansone

10-23-2006, 9:38 PM

I have always read that wood dust is not particularly small as dusts go. Only a tiny fraction of the airborne wood dust is sub micron. Where did you read that?
I will site a wood shop air sampling study from University of Vermont , Burlington VT Dept of Epidemiology and Environmental Health. Do you have a link to a website where we can obtain the information about how this study was conducted?
They ran 13 different machines: belt sanders, drum sanders, routers, shapers, and various saws classified the airborne dust by size. 22.5, 14.1, 5.5, 3.2, 2.0, 1.2 Microns Does this mean that they weren’t looking for anything smaller than 1.2 microns? What did they use to look for the particles? Did they have equipment that could “see” particles smaller than 1.2 microns?

For Example:
In 9 tests they recorded zero % of the material was below 1.2 micron in size. On 4 tests the amount of dust below 1.2 micron was one tenth of 1 % of the total air borne material. By weight. There are 8000 .5 micron particles in one10 micron particle (10/.5 = 20, 20^3 = 8000)…..By weight. So, if you had the equivalent of 12.5 10 micron particles, it would take 100,000 .5 micron particles to weigh the same amount. Maybe that is why Bill is getting such high particle counts?

well just a casual reading of this journal article housed at the NIH seems to indicate that the majority of particles are in the 1 to 10 micron range.

http://ntp-server.niehs.nih.gov/ntp/roc/eleventh/profiles/s189wood.pdf

another more confusing paper seems to show a large concentration of diameters in figure 4 in the 10 micron range.
It looks like both journal article offer good references for other research that you might find useful
http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleForFree.cfm?doi=b202856p&JournalCode=EM

Lou

Ed Morgano

10-23-2006, 10:43 PM

What I was pointing out and your first journal article also finds is that there are particles of .5 micron size and that it takes many thousands of these particles to equal a few larger particles. Bill may have said that the "particle count" was 100,000 times more than safe levels......not that the quantity of dust was 100,000 times safe levels. There is a large distinction to be made between the number of particles in the air and the mg/m^3. Also as your journal article points out, ......"Particles with a diameter larger than 5 µm (“inspirable” particles) are deposited almost completely in the nose, while particles 0.5 µm to 5 µm in diameter (“respirable” particles) are deposited in the lower airways."

In the second journal article that you mentioned they distinctly said that they made a compromise as to the size particles they could look at.

"Limit of detection and blanks
There is a trade-off between the magnification and the area of
view, such that in order to properly measure particles greater
than 100 micron diameter, it is necessary to reduce the magnification
so that these particles are completely within the field
of view. The 206 objective is the compromise. The limit of
resolution of the microscope imaging system at this magnification
is about 2 microns."

Ed

Post revised to clarify which journal link I was quoting from.

lou sansone

10-24-2006, 7:09 AM

hi ed
I am not arguing from a specific POV, but this thread caught my attention and just a little digging sort of shows that John R's assertion that sub-micron particles due to wood working are not typical, as the first article cited indicated. The quote you captioned in the previous response only indicates the typical place of residence of particulate size, and not the fact the in wood working 0.5 micron particles are generated on a regular basis. The actual distribution cited in the first article reads :

"Total airborne dust concentrations are described as mass per unit
volume (usually milligrams per cubic meter). Wood dust generally is
collected by a standard gravimetric method that involves using a
sampling pump to collect a known volume of air through a special
membrane filter contained in a plastic cassette. Some sampling studies
reported that the particle size distribution varied according to the
woodworking operation, with sanding producing smaller particles
than sawing, but others found no consistent differences (IARC 1995).
The majority of the wood dust mass was reported to be contributed
by particles larger than 10 µm in aerodynamic diameter; however,
between 61% and 65% of the particles by count measured between 1
and 5 µm in diameter (IARC 1995)."

Is it possible that the collection and detection equipment is not sophisticated enough to collect and measure sub micron particles ? That could be. From your professional experience, what type of equipment has been used to gather sub micron particle size information ?

Where in the second article did you find :

"What I was pointing out and your journal article also finds is that there are particles of .5 micron size "

?

IRT the second article there is an obvious reasoned choice as to the range of particles to captured and analyzed. One could take a reasoned positioned that the researchers understood sub-micron particle size wood dust is not typical and therefore designed the experiment to capture the vast majority of wood working generated dust particles in the micron range and not the sub micron range. Again I would refer you to figure 4 in the second article for a crude distribution of the particle size. They are clustered in the micron range and not in the sub micron range. I think john's point stands, but enjoy reading journal articles and welcome addition data.

Lou

Tom Jones III

10-24-2006, 8:30 AM

Ed Morgano

10-24-2006, 8:41 AM

Tom,
I'm most likely in the same boat as everyone else on your first question......What level is actually harmful to your health? Three standards already exist and I'm sure over time that more data will be accumulated to show which of these standards is actually necessary to protect our health and to what level.
On your second point, I agree completely. That is why I think the testing that Bill Pentz is doing will be useful. He is taking base line measurements right outside of each shop that he tests. Bill has put a lot of effort into doing these tests and I think he should be thanked for his efforts.

Jay Albrandt

10-24-2006, 12:51 PM

Mr. Witter,

You mis-quote what I said.

Please reread my first post. I clearly state that I am a layperson and my report of Bill's findings were MY interpretation (not Bill's) of a TON of information that I am still trying to wrap my brain around. In statement #2 of my first post, I said that there were 100,000 MORE residual particles in the air when compared to the outside air...........NOT 100,000 TIMES more particles. The actual readings from Bill's instruments showed that the ambient air outside my shop had 134,520 particles in the 0.5 micron and below range and 3,820 in the 5.0 micron range and below. The residuals inside my undisturbed shop were 144,290 and 1,940 respectively.

Furthermore, and I mean no disrespect to Mr. Pentz by admitting this, but I was very skeptical about the little machine he used to test my shop air. During the test I wrote down the name and model number of the device and called my friend who has a degree in environmental health and who works for the City of San Diego. I gave him the whole story and he was amazed that some guy bought this device himself. He said the machine is very expensive and that it is very acurate. Why do I bring this up? Bill is the first one to do what he is doing, he is spending his own money and time doing it, so lets give him a break and wait until he finishes and compiles the information before we try to compare how his findings differ from other studies that were probably done under different conditions.

Peace,

Jay

Phil Thien

10-24-2006, 2:19 PM

Alan Simpson

10-24-2006, 2:48 PM

By residual particles, are you referring to the particles in your shop air before or after cutting???

Ed Morgano

10-24-2006, 5:11 PM

By residual particles, are you referring to the particles in your shop air before or after cutting???

Alan,
He said: "The residuals inside my undisturbed shop were 144,290 and 1,940 respectively...." so I think he means before cutting.

Ed

Phil Thien

10-24-2006, 8:03 PM

Don Baer

10-24-2006, 9:36 PM

Perhaps you can answer a simple question for me, given your familiarity w/ this device. Are the numbers being quoted per cubic centimeter or cubic meter or ?

TIA,
Phil

Neither it is uM/cu.ft.

Jay Albrandt

10-24-2006, 11:38 PM

Phil,

DUH!

Yes, of course I made a mistake when I started the thread. The difference between the ambient and residual measures were approximately 10,000 for .5 microns and below. Not the 100,000 that I first stated.

I apologize to everyone for this confusion.

Jay

Bob Dodge

03-04-2007, 1:45 PM

Bill,

Also, It looks like the amperage and CFM tests reported by clear vue owners show that they run only about 10.8 Amps @ 230V for 1100 CFM. This is only half the amp rating of a 5 HP motor.

This is well within the limits of a 2HP 11- 12 Amp motor at 1100 CFM. Are these reports correct? If so why are you running a 21 amp 5HP motor to get 1100 CFM and wouldn’t a two or three HP accomplish the same thing?

Sincerely,
Robert Witter

Robert, (re, HP/CFM)

I'm running a Pyradia/Belfab 2hp (8.5amp) Baldor Industrial Premium-Efficiency motor with 12.5" impeller in my dc. CFM is virtually identical, at just under 1100 CFM(6" test-pipe). With seasoned filters, I'm pulling 10.8 amps, which is exactly as you've stated. With filters removed, 11.1 amps.

The motor has a 1.15 service-factor rating, and therefore can operate at 9.8A on a continuous basis. With carefully planned duct-runs, it's a simple matter to take full advantage of the available horsepower at my largest machines.(6" port). The only circumstance under which I'd require more horsepower(3 hp), would be when operating an unrestricted branch, such as a very short 6" or 7" pipe/hood, or twin 5" drops with 7" main, operating simultaneously.

Bob

Bart Leetch

03-04-2007, 4:43 PM

Whew my head is spinning. I think I'll go out to my shop & put on my dust mask turn on my overhead filter & use my unperfect DC system with big pleated filter as needed in my closed up shop & become unconfused & find some enjoyment in life. :confused: :( :eek: :rolleyes: :p :) :D Ya I know all the wrong discriptions but some of us don't have the bux or choicest location to install the very best.

In my Dad's custom cabinet shop all the chips fell on the floor & he smoked cigars until 1960 or 61 50 Rotan from Fri-Mon & a handfull to get through till Fri evening & he didn't smoke at work. The Dr. has him on a once a year check up at 85 years old. Dr says I don't need to see you so often your in good health perfect lungs.

There is a lot involved here its not just DC performance.

Dave Novak

03-04-2007, 4:56 PM

What would make the most sence is if manufactures owuld admit that DC is an integral element of woodworking equipment would just design/engineer it into the machines as they were built. Most of my tools have to be seriously modified for any DC system to work sort of well, and even high end stuff like my Laguna band saw doesn't collect dust as efficiently as it should. Why can't they use the big motor on the machine to simultaneously drive a small but very efficient internal DC system? It would be easier to periodically dump a 5 gallon bucket built into every machine than it is to drag hoses around to every machine and still have to sweep up when I'm done.

Wilbur Pan

03-05-2007, 12:06 AM

Arguing about whether there are "a lot" of the smaller particles is absolutely pointless without having a frame of reference. Answering 2 questions is requisite for an intelligent discussion on this topic.

* First what is a measure of the smaller particles that is known to be harmful to human health? If only a very small number of particles is known to be harmful then the research may be correct that there are very few particles generated, but if the very small numbers could kill you then that changes the discussion.

* Second what is the baseline of the smaller particles? Combine this answer to the answer to the first question to form an objective goal for air quality. How many of these small particles are in the air in my house, my office, the park? I don't think I want to know what I'm breathing during a 60 minute run through Houston but it would be useful to know how it compares to 60 minutes in my workshop.
I can't answer the second question but I certainly can answer the first. Just so you know, my day job is being a pediatric oncologist, so I know a bit about how these "safe" levels are determined.

The concept of a "safe" level of fine dust exposure is an oxymoron. The risk of fine dust causing a major health issue follows a dose response curve in several epidemiological studies looking at health problems in woodworkers (http://www.sawmillcreek.org/showthread.php?p=454754#post454754). What this means is that the minute you start inhaling fine dust, you assume some level of risk for a major dust related health problem, and that the risk increases the more that you are exposed.

To look at it another way, if you took 100 woodworkers and exposed them to the amount of fine dust generated by cutting a sheet of MDF, perhaps one of them would come down with respiratory problems,and the rest would be just fine. Cut 2 sheets of MDF, and maybe 2 will have health issues. With 3 sheets of MDF cut, 3 woodworkers will be sent to the doctor, and so on. The more sheets of MDF that are cut, the more woodworkers will be affected. However, the intensity of the health problems will be pretty similar, regardless of how many cut sheets of MDF you happened to be around when your lungs got affected.

The concept of a "safe" level of dust exposure is really just what is considered to be an acceptable number of health problems related to dust exposure. OSHA mandates an acceptable dust level exposure of 15 mg/m3. This does not mean that if you are exposed to 14 mg/m3 that you will be just fine. Exposing 100 woodworkers to 14 mg/m3 of dust will still give some number of them health problems, even if they were not exposed to a level of dust that exceeded OSHA standards. It's just that OSHA has determined that for various reasons, that number of new patients was acceptable. The NIOSH standard is more strict -- 1 mg/m3. Even at this level of dust exposure some fraction of woodworkers will come down with respiratory problems. It just will be a smaller fraction that NIOSH has determined to be acceptable.

Now, does this mean that no one should be doing woodworking? Of course not. I know all this and I am still setting up a woodworking shop in my basement, just like I know that whenever I drive I could be involved in a fatal car accident, but I drive to the grocery store anyway. But I am mindful of the risks involved, and I am certainly taking measures to limit my dust exposure as much as possible.

Wilbur Pan

03-05-2007, 12:33 AM

I have always read that wood dust is not particularly small as dusts go. Only a tiny fraction of the airborne wood dust is sub micron.

I will site a wood shop air sampling study from University of Vermont , Burlington VT Dept of Epidemiology and Environmental Health.

They ran 13 different machines: belt sanders, drum sanders, routers, shapers, and various saws classified the airborne dust by size. 22.5, 14.1, 5.5, 3.2, 2.0, 1.2 Microns

For Example: In 9 tests they recorded zero % of the material was below 1.2 micron in size. On 4 tests the amount of dust below 1.2 micron was one tenth of 1 % of the total air borne material. By weight.

How does this compare with your tests? How are you getting 100s of thousands times more 0.5 micron material?
It looks like you are comparing apples and oranges. The amount of fine dust will be a small fraction by weight because the dust particles are smaller and weigh less individually. From a health standpoint, though, what matters is the number of fine dust particles, which can be very high even with a very small fraction by weight.

Here's some math to illustrate this point. Let's pulverize 0.1 mg of walnut into 1 micron particles. This is 1/50th of OSHA guidelines for fine dust exposure. The density of walnut is 0.5938 g/ml, so 0.1 mg of walnut takes up 0.0002 ml. This seems like a small number but it actually is 200,000,000 cubic microns. So, 0.1 mg of walnut could make 200 million micron-sized particles.

Now let's say that only 1/10th of 1% of that amount of walnut turns into 1 micron sized particles. That's still 2 million micron sized particles from that small amount of wood.

The point is, very small amounts of wood can generate huge numbers of micron sized dust particles.

As far as the amount of fine dust that cutting wood actually generates? You'll need to come up with the actual citation for the study you cited, but here's one for you:

Hursthouse A et al. A pilot study of personal exposure to respirable and inhalable dust during the sanding and sawing of medium density fibreboard (MDF) and soft wood. Int J Environ Health Res. 2004 Aug;14(4):323-6. The amount of respirable and inhalable dusts from sawing and sanding MDF and softwoods at the operator position in a typical cabinet-making workshop was measured. Exposure levels for the total inhalable fraction (<100 micron) were 6.9-91 mg/m3 for MDF and 2.5-45 mg/m3 for softwood. For the respirable fraction (< 10 micron) levels were 0.4-13 mg/m3 for MDF and 0.4-2.9 mg/m3 for softwood.

The ACGIH guideline for total dust exposure is 1.0 mg/m3 for an 8 hour period. Also, the dust that is thought to be the cause of respiratory problems and cancer risk is the inhalable fraction. This means that one sawing or sanding operation alone could expose a person to more fine dust alone than the amount of total dust he/she should be exposed to for an 8 hour shift.

Justin Henry

03-16-2007, 11:50 AM

The more I read ... and learn I guess ... I'm coming to the thought that without spending so much money to almost recreate a sterile hospital surgical ward in my shop, I will never be "clean enough" or safe enough.

Not willing to reach that cost point nor honestly care to. So for me sticking with primary chip/dust collection and a respirator when I've got to work with mdf is the way I'm going to continue doing things.

Many have done a great amount of research and continue to do so and kuddos to you all.

I live near a city and bet my outside air is lousy anyway. And have to breathe that 24x7 vs shop time of maybe 20 hours a week at best. Not much I can do about that outside stuff at that. Life goes on

Ben Thoron

04-12-2007, 9:31 AM

Jay- I'm interested in the Clear vue Cyclones, I notice that you live in San diego. Is there any chance you can show me your set up?

Ben

Jay Albrandt

04-12-2007, 12:20 PM

Ben,

PM me your contact info and we can set up a time.

Jay

Steve knight

04-13-2007, 1:51 PM

modifing machines can be critical to good dc collecting. I work with almost all tropicals and I ahd to work rpetty hard to really catch the dust from the machines. the tablesaw needs a overhead gaurd with dc to really be able to catch dust. all my tools make super fine dust when cutting padouk and ipe and blooodwood and such. far finer then american woods. for the most part these wodos make only fine dust and not much in the way of shavings. I had problem with my cartrdige filters letting dust out. when I went to the larger blower on my clearview dust was blowing out the filters. I debated on using 4 or 6 cartrides but they are such a hassle to blow out I went with a bunch of bags from ameican fabric filters.
I doubled with reccomended surface and they work great. the bags never fully inflate. but it took 6 months or so before the bags really stopped letting padouk and ipe dust through them.
http://www.knight-toolworks.com/pictures/dcbags2.JPG

Abe Low

12-23-2007, 9:52 PM

I couldn't begin to do the scientific comparison done by Bill Pentz and the analysis in the above posts but.... All I need do is check the ultra fine dust that accumulates over the long time periods in the most remote places like on top of my ceiling joist or on top of my shop flourscent lights to convince me there is lots of submicron particles that permeate everywhere and take lots of time to settle down.
Personal sensitivity is an unknown until it's too late. Sort of like experimenting with illegal drugs.
I put in two air scrubbers, a central Clearview cyclone connected to my Unisaw (which also has the Excalibur blade cover / dust collector), Jointer, Planer, Inca bandsaw, etc. The cyclone is outside of the shop in a lean-to sound insulated shed. A second bandsaw and radial arm saw have a chimney sweep collector with an internal hepa filter installed.
In addition to all this, I open the front and rear doors to keep a slight breeze going through the shop.
BTW, both my parents and younger brother died from cancer so I am perhaps a bit overly cautious.:)

And yes, Bill Pentz is a friend of mine.

Will Blick

12-24-2007, 2:08 AM

Whenever these threads start, we always get the naysayers, such as, my Dad cut wood till he was 90, and my outside air is more polluted, so who cares, etc. I respect the position these people have, but just like smoking cigarettes, many people don't care and smoke their entire lives, while others would never smoke as they know its potential injurious to their health. Wood dust is no different, many people are concerned, and many are not concerned....

So I respect the work Bill Pentz and others are doing to gain as much real world data as possible to help others. Bill P has become a DC angel to this field, dedicating his valuable time to helping others. I personally want to thank Bill P again for all he has contributed to this important subject matter.

I am hopeful we will learn more about what actually is injurious regarding wood dust. What is the major contributing factors? Particle size, length of exposure or does it relate more to the types / species of wood dust? Bill himself was greatly effected by Cocobolo wood dust, which turned out to be one of the more toxic woods to work with, which at the time, he was unaware of. I am not sure science has all the answers to these questions, but hopefully we will learn the state of the science through generous contributors to threads like this.

It's strange how some people can smoke their entire lives and live to their 90's, while others die of lung cancer in their 40's. Of course, with smoking, we can look at family history for clues of how it will effect us, no guarantees, but at least indicators. I am curious if there is certain pre-existing health conditions that might make some people more prone to being harmed by wood dust vs. others. Maybe those with a strong history of airborne allergies? Those who frequently get lung infections, bronchitis, etc.? I have a suspicion the species of wood dust plays a big role in how we are effected.

One thing is certain, in addition to all the great contributions to maximize DC, such as venting outside, good shrouds at the machines, blowing out the shop when the dust settles, always trying to work with doors open, etc. I would think wearing a good respirator has to be atop the list. If the respirators filter down to .3 microns like 3M advertises, this has be one of the most significant tools to reduce the risk of dust illness. I assume this is a consensus?

Dan Racette

12-24-2007, 11:10 AM

I thank all of you who have taken the time and effort to provide us here at Sawmill Creek with the information that you have collected on your travels. I know that you will be faced with biting criticisms, and you will have to provide excessive explanations for your efforts, probably more that it may seem worth. It is, however, worth it to me, personally, to hear this information. I believe, very strongly, in Wilbur's explanations. They lead me to my conclusions in my own shop. I have habits and practices in my shop that are now common place, whearas, before, they were second thoughts. Previously, I had a Dust collector. Now, I have a Dust collector, and auto-start vacuum, and an ambient air filter, and a budget started for a cyclone upgrade. Also, Dust collection runs with no exceptions. NO, "Oh, I just got one more cut" because I only have one set of lungs, and repeated exposure with all those "just one more cuts" adds up over time, and that's going to make me one of those woodworkers that has a hospital visit. I spent a few summers working in a paper mill and the "cleanest" part of the mill was the finishing area where they trimmed and cut the sheets and rolls. It was the dustiest, and had the highest incidents of cancers, due to the particles of dust, even though, at face value it was "cleaner" than the rest of the mill. Small micron particles are becoming the eye-opening issues all over, in homes and businesses, and reducing exposure to as near zero as possible is the key.

Thanks all for helping us do this.

Dan

Will Blick

12-24-2007, 11:47 AM

Dan, interesting post... more evidence of the sub micron particles being the culprit. thanks for sharing.

Another issue that has really opened my eyes to this dust problem is...... workers in grain plants (corn, wheat, etc) also suffer terrible (often fatal) health problems with fine dust. One would suspect, that since this dust is from foods we eat on a regular basis, their dust would not be toxic.

Therefore, it stands to reason, wood dust, specially MDF has the potential to be as dangerous, or probably more dangerous, as wood is not an edible food. It also seems, based on the OP's comments of Bill P's results, that breathing polluted outside air from living in industrious areas will never have anywhere near the fine dust concentration as working around wood power tools, as the dust concentration is diluted many million times by the huge air mass in our atmosphere. I found this part of the OP's comments very interesting....i.e., by simply opening the garage, the particle concentrations were drastically reduced, demonstrating how quickly fine dust particles will dilute, if given the opportunity.

I am curious of Bill P's comments on this.... and when this thread comes near a close, it would be nice if Bill posts a "hit list" of Dust Safety procedures, in order of priority, in order of cost, etc.

Carroll Courtney

12-24-2007, 11:48 AM

I guess there is always a motive for everything.A man drives for several hrs to look over a collector and charges nothing.Fellow woodworkers want to pound him,cause there is a motive.Well if your sick and go to a doctors office and he's there what is his motive?Its not because he or she wants to help,its because you have insurance.Citys are now placing camera's at intersections because their concern about safety--bull--they want your money.Get mad at the right places and at the right person.A guy drives several hrs,and he may write a book or an article on systems that he has tested,so what,I will purchase the magazine and read it.And you want to pound him because of a motive.Ease up alittle and write about your study and the systems that you have tested and we all can learn alittle.

Wade Lippman

12-24-2007, 12:05 PM

1. All dust hoods and guards must do two things: They MUST be an effective physical barrier to dust being spewed away from the blade, and thus away from the air collection stream. If you don't have this first, then no matter how much CFM you have at the tool, you simply are not going to catch the harmful dust.

That is true for high momentum debris, but not an absolute.
I leave a hose near my lathe when I sand; you can see this cloud of fine dust moving off to the hose. It is certainly over 95 effective with no hood or guard.

3. I learned that my filters do an excellant job of cleaning the air in my shop. By running the cyclone and not cutting anything, the filters reduced the total particles from comment #2 by half.

No doubt, but an air cleaner would do the the job just as well, using 10% of the power and making less noise.

6. For those of you who have a Pentz' design cyclone. I have the 14" impeller and my real world, direct measurement came out to be 1,099.564 CFM, with the 5hp Lesson motor at only 10.8 amps. That means I can upgrade to the 15" ClearVue impeller and get another 300 CFM when I expand my shop and still not overload the motor. smirk!
I have always wondered why they don't sell it with a larger impellor or a smaller motor.
Jay
...............

Andy Calenzo

12-28-2007, 1:51 PM

Wade,

This is Andy – one of the engineers here at Oneida Air Systems. Thank you for your post (reference: post #15) that addresses the fact that the mass of the dust particles generated by a tool has an effect on the air flow requirement at a tool port. I have often thought that you don’t necessarily need 5000 feet per minute of air velocity at the tool port when you are sanding. I am fairly certain that you can get by with say 4000 feet per minute of tool port air velocity when you are sanding because it doesn’t take a lot of force to induce fine dust particulate to enter an open tool port when the dust involved weighs very little. I also think that when it comes to sanding dust, the most important factor is the amount of distance between where the dust is being generated relative to the location of the collection port (you basically say the same thing when you state that you can actually see the light sanding dust moving through the air to your dust collection hose located within close proximity to your lathe).

You also make a valid point when you state that air cleaners can remove airborne dust floating in the shop far more efficiently due to lower power consumption and with far less noise than Jay’s cyclone that generates a 90 dBA sound pressure level (90 dBA at a distance of 10 feet as measured by me using a handheld sound meter). My pet peeve with these air cleaners is that they are normally mounted to the ceiling and I personally believe that this location is the opposite of where an air cleaner should actually be mounted. I believe that an air cleaner should pull airborne dust down toward the floor away from the operator’s eyes, nose and throat. This would mean a low wall mount unit and I am not sure that such a machine exists at the present time.

Regarding the use of a 5 horsepower motor on a cyclone dust collector that presents a load that requires only a 2 or 3 horsepower motor, this really doesn’t make a lot of sense. Consider the fact that starting current on single phase motors is typically 6 to 7 times that of the full load amperage marked on the motor nameplate. With this in mind, why would you specify a motor (i.e.: the Leeson 5 horsepower motor used on Jay’s cyclone) that has a specified ‘Locked Rotor’ (i.e.: inrush) amperage of 107? The inrush amperage on our 3 horsepower Baldor motor (reference catalog no.: VL3606T) is specified at 86 amps and I get negative comments from customers when I inform them of this much lower inrush. The 21 amp inrush difference between the Leeson 5 horsepower and the Baldor 3 horsepower motors can be significant in shops that have limited electrical service. Another aspect of the electrical hookup required for a motor that has a full load amperage of 20.8 amps (again, the Leeson catalog number: 121692 on Jay’s cyclone) is that you would need to use a 30 amp circuit breaker to supply the 230 volts to the dust collector circuit. This means of course that the wire which must be used needs to be rated at a current carrying capacity equal to the circuit breaker steady state trip point of 30 amps. To conclude here, bumping the size of all the electrical components in the power circuit used to run a 5 horsepower motor as compared to the smaller wire and magnetic starter requirements when using a smaller 2 or 3 horsepower motor adds up to additional expense that really isn’t necessary in this case.

Bill Pentz

12-29-2007, 2:24 AM

Personal
I’m a retired biomedical engineer and university engineering instructor who was blindsided by the “best” magazine rated cyclone system and vendor designed ducting. In spite of what you may have heard I am not a vendor, own no part of any dust collection firm, and my only relationship to these firms is most now sell variations of my earlier cyclone design that I published on my Cyclone Modifications web pages nearly eight years ago. I do get a small royalty for allowing Clear Vue Cyclones to manufacture cyclones of my latest design which provides about a third better airflow efficiency and more than five times better fine dust separation than the closest competitor who uses my earlier cyclone design.

Background
Two weeks after I finished my holiday woodworking I landed in the hospital from a bad allergic reaction that caused double pneumonia and congestive heart failure. The hospital got me stabilized but I was not improving so they brought in a respiratory specialist. He looked into my airways and had me fill in a comprehensive activity form. He suspected my problem was an allergic reaction to the dust created by my woodworking. I said impossible. I always wore a 3M NIOSH approved fitted dual cartridge dust mask when making fine dust. I had the “best” and most expensive small shop cyclone system with vendor designed and supplied ducting that money could buy which left me with a clean looking shop. I also had a recent full allergy test that showed no reactions. And, the only time I had to do woodworking was on a few Christmas gifts that were finished a few weeks earlier. My respiratory specialist shared he was a fellow woodworker and praised my efforts saying most woodworkers put dust collection off when it should be a top priority. He then said even those who try to minimize their fine dust exposure fail because most small shop dust collection equipment creates higher airborne dust levels than if we just wore a good mask and kept a fan blowing in an open doorway.

Medical Risks
My doctor explained airborne dust poses many health risks, but it is the fine invisible dust particles sized under 10-microns which often do the worst long term damage. He said all woodworkers should check a good wood toxicity table (http://www.billpentz.com/woodworking/cyclone/WoodToxicityTable.cfm) before working with any wood, and realize that these tables are frequently dated plus we each can have stronger than normal reactions to certain woods. These tables give the dangers of woods, but ignore the wide range of additional chemicals from oils, glues, finishes, stains, insecticides, defoliants, molds, etc. that can also be poisonous, irritants, sensitizers (create allergic reactions), and increase our risk of cancer. He strongly dislikes current advertiser hype selling “fine” filters that create a dangerous false sense of security. Our small shop dust collector, cyclone, vacuum, and air cleaner filters are rated when fully seasoned meaning filled with dust in the filter pores that does not come out with normal machine shaking type cleaning. The American Society of Heating Air-conditioning and Refrigeration Engineers (ASHRAE) sets filtering standards. Their standard says indoor filters must be rated when clean and new because a new filter will pass up to 20 times larger particles than one carefully seasoned. In short, these filters pull off the visible dust and freely pass the fine invisible 10-micron and smaller particles. These particles take years to break down and dissipate so they just keep building in our shops. My doctor said this 10-micron and smaller particles known as respirable dust, goes right past our normal body protections to lodge deep in our tissues where we can’t easily get rid of it. Every exposure to this fine dust causes some measurable loss of airflow and some of that loss becomes permanent leading to fibrosis and other long term respiratory disease. My doctor strongly recommended I get medical air quality tests run on my shop and home.

Testing
I paid for a medical air quality test on my shop and home. My inspector was one of the senior medical air quality inspectors used by Cal-OSHA. My inspector took one look at my shop, praised my dust collector as being really impressive looking then said there was zero chance this unit would pas an OSHA air quality test. He explained that hand sawing less than 7” of ¾” stock generates enough fine dust to cause a typical 2-car garage sized shop to fail an OSHA air quality test. He saw I had not upgraded my tool hoods, used a small blower, used ducting too small to carry the needed airflows, and used what looked to be a wide open filter. He said decades of air engineering show we must upgrade our tool hoods to block, trap and deliver the fine dust for collection. A typical saw blade launches fine particles at over 100 miles an hour, yet an average cyclone or dust collector only moves air at about 40 miles an hour, so without upgraded hoods most of the fine dust is going to escape collection. Likewise, it takes a 3 hp or larger dust collector or 5 hp or larger cyclone to move enough air at our larger machines for good fine dust collection and be able to overcome the other resistance levels in our shops.

He explained the issue is not blowing the fine dust around which can be done with the slightest breath, but instead moving enough volume of air to pull in the fine dust before it can escape from our tools. Once this fine dust escapes it spreads so quickly that there is no chance of passing an air quality test even with a big exhaust fan and air cleaners. We must capture the fine dust as it is made. Decades of air engineering and testing show we need roughly 50 feet per minute (FPM) airspeed to overcome room air currents and pull in the fine dust. Unfortunately, we have to move that airspeed not over the typical 4” duct opening needed to provide the roughly 4500 FPM airspeed needed for good “chip collection” but instead over a huge area all around the working area of our machines. We already know that a vacuum only collects right next to the nozzle. The reason is sucked air falls off in speed at roughly 3 times Pi times the distance squared. Wet a finger and see how far away from your lips you can feel blown airflow then try again with sucking. Most can feel a blown air as far as they can reach, but within an inch or so we stop feeling airflow from sucking. This is why we need to move a lot more air to pull in the fine dust than needed for good “chip collection” meaning collecting the same sawdust and chips we would otherwise sweep up with a broom. His test equipment showed just turning on my cyclone after three months of doing no woodworking stirred up enough dust, most from that filter, to make my shop air dangerously unhealthy. His air volume meters showed most of my ducting severely restricted my total airflow which explained why my ducting mains kept plugging and building up dust piles. He warned me that ducting piles pose a serious fire danger and when they break loose create one of the few times when the dust air mixture can be explosive, plus that dust slamming around ruins aluminum impellers, motor bearings, and filters. A few minutes of actual woodworking showed my tool hoods sprayed fine dust everywhere and pushed the dust levels to more than double OSHA maximums. He said was actually pretty good as most small shops he has tested have airborne dust levels up to 5 times the OSHA maximum which is just about all air can carry unless strongly stirred.

Research
Finding out what it takes to get good fine dust collection was a nightmare mess of mostly ignorant vendors and people making logical sounding comments when they did not have a clue as to what they were really talking about. I discovered that our small shop vendors were mostly ignorant of required airflows, ducting, and filters needed for fine dust collection, but all claim to be experts with many offering fine dust collection systems and ducting design services that just plain don’t work for anything including good “chip collection”. It was not until I discovered that those top commercial firms like Donaldson Torit and Cincinnati Fan actually shared engineering information ample for an informed viable fine dust collection system. Likewise, buying my own set of gauges showed all of the small shop cyclones worked poorly. That made sense because all were near identical copies of each other based on the 1962 New York State, Department of Labor public domain cyclone design. That cyclone was designed to have huge internal turbulence to break the fine from heavy dust, then drop the heavier dust and chips into a bin while blowing the 30-micron and smaller airborne particles away into the outside air.

Woodworkers come from all walks of life and most tend to be pretty bright people who have much to contribute. Almost every serious woodworker who had bought or built one of these near identical cyclones was pretty unhappy with how poorly they worked. Many came up with suggestions as to how to improve their operation. My friend Jim Halbert looked over an interesting scientific article on reducing internal cyclone turbulence and came up with his “neutral vane” to extend the inlet greatly decreasing internal turbulence. Dizzy came up with a great filter stack with lower cleanout that stopped us from having to take a “dust bath” every time we cleaned our cyclone filters. Larry Adcock with his WoodSucker cyclone came up with a spiral air ramp to further reduce internal turbulence plus tried a more efficient caged impeller to get better airflow with less horsepower. I took these and many other suggestions, tried each, and added my own refinements to create a much more efficient cyclone that instead of averaging 4.5” of resistance was near 3.5”. I shared what I did on some forum posts and was soon overwhelmed with too much email in self defense I put this information onto my personal web pages which later in May 2001 went onto my Cyclone and Dust Collection Research web pages that my doctor talked me into creating.

Although this cyclone has better airflow, its separation level was dismal. Before modifications these cyclones worked just about as well as $25 plastic trash can separator lids meaning they pass virtually all 30-micron and smaller particles. If we vent outside this is not an issue because these sized particles dissipate into the outside air. When run into a filter, these sized particles will quickly clog a fine filter. That is bad news because as the filters clog we have to clean them. If we don’t clean then the air pressure rises enough to force the fine sharp particles to cut and tear their way through the filter pores soon ruining fine filters. Cleaning also forces these sharp particles through the filters which causes them to also fail early. The only option is to make the filter area huge. Instead of 1 square foot of filter area for every 20 cubic feet per minute (CFM) of airflow for a 30-micron filter we end up needing roughly 1 square foot of filter for every 4 CFM of dirty airflow. The fine filter material is expensive and we end up with huge filters even when the filter material is folded into pleats and delivered as a cartridge filter.

My research showed to get the clean air I wanted I either needed banks of graduated filters or a much better separating cyclone. The filter banks were too much trouble to clean so I went back to the basic physics on cyclone design. The existing designs just were not going to do much to improve separation unless I significantly increased internal airspeed which was going to cost dearly in terms of blower sizing. At one time I designed rocket motors, so felt it would not be that tough to design a viable simple cyclone. I was wrong. After a year of work and building what my family called Mount Cyclone in our backyard I was little better off than I was when I started. While talking with one of the Dwyer Instrument engineers about airflow measurement I had an inspiration. When I added that to my cyclone it suddenly became a far better separator. After a few years of refinement it became what is now shared on my Cyclone and Dust Collection Research web pages. Four medical schools and three university labs have now tested this cyclone design. It provides about one third more efficient airflow and just over five times better separation than my prior design which includes all of the innovations from my Cyclone Modifications web pages. Moreover, unlike most existing cyclone designs, my design is scalable and still provides its efficiency as its size changes.

Collector Sizing
Airflow Needs
That leaves the issue of picking a dust collector type and sizing. If we only want good “chip collection” a good CFM requirements table shows we only need to move 350 to 400 CFM depending on what we have for our larger stationary tools (http://www.billpentz.com/woodworking/cyclonenew/images/CFMRequirementsTableSmAAF.gif). To provide good fine dust collection we need to move more air. I strongly recommend targeting for good fine dust collection at around the 1000 CFM range for our larger stationary tools. Most of us know that the slightest breeze or breath will move fine dust. Careful testing shows that instead of the roughly 4500 feet per minute (FPM) airspeeds needed to pick up sawdust and heavier chips, we really only need about 50 FPM airspeed to provide good fine dust collection. Unfortunately, we are not blowing the fine dust around but instead sucking. Sucking pulls air from all directions at once so airflow falls off at roughly 3 times Pi times the distance squared. Think about how little area we can suck up with a vacuum compared to how much it will move when blowing. For example, wet a finger and see how far from your lips you can move it and still feel blown air. Now try again with sucking. Most find they can feel blown air as far as they can reach but sucked air can only be felt when our finger is right next to our lips. What this all means is we have to provide that 50 FPM air speed over a much larger area to cover all of the working surfaces of our tool, not just the exhaust port. From our air formula FPM=CFM/Area we end up being able to compute a need of 800 to 1000 CFM depending upon level of fine dust collection to get the same fine dust on the same tools that with 350 CFM would give us great “chip collection” meaning collecting the same dust we would otherwise sweep up with a broom.

Shop Resistance
We next need to determine the maximum and minimum resistance that we can expect in our shop. This maximum resistance will help us size our impeller and the minimum will help us size our blower motor. Our Maximum resistance will be about 2.5” with a fully seasoned filter, about 1.7” more to pull air from ducting across an average 2-car garage sized shop, another 2.32” to pull air for a machine with two dust ports such as a table saw with cabinet and blade guard hoods, the about 3.5” for a typical cyclone resistance giving a total of almost exactly 10” resistance. The resistance in my shop is higher because it is bigger than a 2-car garage and I use some tools that take higher airflows.

Impeller Sizing
Regardless we can take our 1000 CFM and 10” of resistance and look at just about any good fan table to size our impeller. We look at backward curved (BC) impellers to lower the sound levels. Going to the Cincinnati Fan Pressure Blower (http://www.cincinnatifan.com/catalogs/PB-1102-internet.pdf) tables and looking down the 10” resistance column on their 3450 RPM blower table shows we need at least a 15.5” diameter BC impeller with 5” tall blades to exceed our 1000 CFM. That impeller is overkill as it will move 1242 CFM pulling 3.76 horsepower. Their next size down BC impeller is a 14” diameter with 3.25” tall blades. That impeller moves 846 CFM pulling 2.34 hp. This smaller impeller is too small so we need something in between. It turns out that a 15” diameter impeller is near perfect for our 1000 CFM at 10” for most cyclones.

Motor Sizing
To size our motor we go back to that same table with our impeller size to see how much air is moved when we have minimal resistance. Our minimum resistance will be with our dust collection system directly connected to an adjacent tool with a big diameter minimum length duct, large hood and brand new clean filters. New clean fine filters typically have about 0.5” of resistance because their fine strands when new create less resistance than coarser filters with bigger filter strands. As the filters get dirty the resistance rises. Add roughly 1.5” more for hood resistance. Add another 3.5” for cyclone resistance. And add about 0.2” resistance for a 5’ duct and we end up with a minimum resistance of about 5.2”. Going to that same table for our 15” diameter impeller in the 5” column and we see the airflow jumps to an incredible 1715 CFM pulling 4.67 hp. If we look at this same table for that one size smaller 14” diameter BC we see that at 5” resistance it will move 1296 CFM and pull 3.28 horsepower. So yes a 3 hp motor with about a 110% service factor will just barely power a typical cyclone but will not move the air we need at a higher resistance.

In the case of my cyclone design which only adds about 2.25” of resistance instead of the 3.5” of most other designs we end up with a high end resistance of only 8.75” and low resistance of 3.75”. Using that same table we see at 9” resistance we can get by nicely with a 14” BC impeller with 8” duct and get 1023 CFM for 2.76 hp. At 4” of resistance with that same impeller we move 1492 CFM pulling 3.64 hp. In other words my design moves more air more efficiently so we need a bigger motor because the more air we push the more horsepower we use. In fact, I actually design my cyclone to work with either a 14” or 15” diameter BC impeller. Because motors come in stock sizes of either 3 or 5 hp, I choose to use the 5 hp and designed a 15” impeller that will move more air and use more of that motor’s efficiency. I also chose the Leeson motors because they are not imports like most of the other big name motors and they are designed to start under heavy loads like spinning up a large impeller. I also gave up on the light aluminum impellers because they kept breaking blades and slipping down motor shafts. Any time a cyclone dust bin gets full all goes right through the impeller just like a dust collector. At these airflows we can suck a wrench through our ducting and that is bad news for a light aluminum impeller. As for going with a 5 hp ainstead of 3 hp motor, with about a $20 difference in motor cost it made no sense to me to design a unit that could burn up when connected to an adjacent planner. The way most vendors get around the burning up the motor problem is they choke the airflow with their ducting designs.

Cyclone Ratings
Now all of this also shows two huge holes in current cyclone testing and ratings. First, we buy our cyclones to provide separation yet nobody other than me gets their cyclone separation efficiency rated by an outside independent source. Medical school testing of my cyclone design now sold by Clear Vue Cyclones (http://www.ClearVueCyclones.com) or that you can build yourself from my free web page plans shows a 99.9% separation efficiency on particles sized 4.7 microns and larger. The closest competitor is my older design from my Cyclone Modification pages that most vendors now copy to some degree. My older design provides 99.9% efficiency for 25.3-micron and larger sized particles. The other hole is the one found in the last few magazine cyclone tests. Most cyclones today come with huge inlets designed to connect to 8” and even 10” diameter ducting. These cyclone vendors are betting that their motors will last long enough to test with an 8” to 10” duct, but require in their product sheets that you supply ducting that ends up no larger than 6” going to your machines. With these motors built to handle 6 or more times starting loads than running they do great on these tests unless they run too long. Then the smoke comes out of the motor. With buying a very efficient Leeson motor that only draws 20.8 amps at maximum load, this minimizes circuit breaker size, wiring size, and the worry about burning up motors. The magazine test I reviewed a couple of years ago burned up three cyclone motors during testing.

Response
So, to answer a question recently asked on this thread I recommend working outside when making fine dust while wearing a properly fitted NIOSH approved dual removable cartridge respirator mask. When working inside I always recommend venting outside whenever possible. You also need to upgrade most tool hoods and move lots more air. When venting outside provide ample makeup air to keep from pulling deadly carbon monoxide backward into your shop from your fired appliances, flues and exhaust vents. When the weather precludes venting outside, then you still need the upgraded hoods and moving plenty of air. You also need to provide filters that when clean and new provide ample filtering. My respiratory doctor says most should use ASHRAE approved filters that provide 99.9% filtering efficiency on 0.5-micron dust. Now that I have a dust sensitivity I should use filters rated at 99.97% efficiency at 0.3-microns which is the standard for HEPA filters. For those who don’t have ample systems, we need to work in our respirators while making fine dust. Because that dust will stick around until we thorougly clean our shops we should continue to wear our respirator masks until we thoroughly clean out our shops. Because fine dust travels in any shared air, those whose shops attach to our homes through a common door should install a bathroom vent fan that turns on with our lights. With all closed down we will lose little heat or cooling, but will have enough negative pressure to keep the dust from rushing into our homes when we go in and out. Because fine dust is so easily carried on our hair, skin and clothes we should also wear a hat, scarf, apron, and or jump suit whenever working with woods known to be toxic so we can leave their dust in our shops instead of tracking it into our homes, vehicles and other areas we visit.

Closing
Anyhow, that is more than you probably ever wanted to hear and more than I enjoyed writing which is why I put this information on my web pages. Further, on my web pages I don't have to put up with the problem that any time a dust collection thread gets serious and begins to pass real information, all kinds of naysayers come out of the "woodwork" with personal attacks until the forum administrators end up just killing the thread throwing out the good information with the nonsense.

Hope this helps.

Tim Marks

12-29-2007, 7:52 AM

Bill, you say that you are a "biomedical engineer", but according to your own website, you never actually graduated with any degrees. Is this correct?

You also discuss some other lung related issues (being very susceptible to smog while recovering from blood posoning and receiving a near fatal dose of rat poison ofrom an airplane that had been fumigated and not appropriately aired out while you where in the USAF). Is it possible that these two issues contributed to your later sensitivity to wood dust, and maybe most people wouldn't be as susceptable as you?

Is your cyclone based on the 1D2D design that Dr. Gary Hyde at WSU demonstrated in his thesis as the most efficient design for collecting dust particles of the size of concern? Or was it Calvin Parnell at Texas A&M? I seem to remember that you used to give credit him and his thesis on your original web page, but your current web page doesn't reference him.

Rob Blaustein

12-29-2007, 9:37 AM

...Well if your sick and go to a doctors office and he's there what is his motive?Its not because he or she wants to help,its because you have insurance.

Huh??
Not only off topic but an unwarranted and out of place stab at docs, if I read you right.

Bill Pentz

12-29-2007, 5:12 PM

Tim,

You appear to be echoing comments that are neither accurate nor appreciated.

Bill, you say that you are a "biomedical engineer", but according to your own website, you never actually graduated with any degrees. Is this correct?

No, your statement is not accurate. I have two engineering degrees, and a general education college degree that I never bothered to pickup with minors in engineering, physics, math, biochemistry, pre-medicine and psychology. I also completed the course work and thesis projects with a 3.98 GPA for engineering master degrees in computer hardware and software design. In addition, I taught for UC Davis and CSU Sacramento for nearly thirty years before my respiratory problems forced me to retire from teaching. I also worked doing biomedical engineering design for the universities followed by forming my own biomedical computing firm that provided consulting to a wide range of customers.

You also discuss some other lung related issues (being very susceptible to smog while recovering from blood posoning and receiving a near fatal dose of rat poison ofrom an airplane that had been fumigated and not appropriately aired out while you where in the USAF). Is it possible that these two issues contributed to your later sensitivity to wood dust, and maybe most people wouldn't be as susceptable as you?

Although my prior health history did not slow my active life, I am sure it contributed to the extent of my current respiratory damage. At the same time, the record is clear that between one allergy test and another I went from no wood allergies to such severe sensitivity that an allergy test left nasty welts and boils showing I quickly sensitized to a variety of woods. In terms of rapidly developing allergic reactions I am not alone as many have written me from all over the world that they also quickly developed serious sensitivity to teak, rosewood, sandalwood, walnut, oak, cocobolo, etc.

Is your cyclone based on the 1D2D design that Dr. Gary Hyde at WSU demonstrated in his thesis as the most efficient design for collecting dust particles of the size of concern? Or was it Calvin Parnell at Texas A&M? I seem to remember that you used to give credit him and his thesis on your original web page, but your current web page doesn't reference him.

My cyclone design skills benefited considerably from a wide range of sources including the excellent work you mentioned, but my current cyclone design is my own unique design. The basic small shop indoor cyclone design that almost all sold had serious problems. To make repair I studied the available research, consolidated, tested and refined suggestions for improvement from other woodworkers, and came up with the changes on my Cyclone Modification web pages. Although that is the design that most small shop vendors now sell to one degree or another, I found it still far too inefficient in separation and airflow. That sent me back to the physics of swirl tube separation leading to my own unique cyclone design that optimizes both airflow and cyclonic separation.
bill

Art Mann

12-29-2007, 7:17 PM

Yawn! Here we go again.

Hank Phillips

01-02-2008, 1:21 PM

I've been doing a lot of reading about dust collection as I'm trying to decide what route to go, and that includes Bill's site as well as others.
I just have a question for Bill, what company were you a senior engineer at when you "invented much of the technology now used world wide for smog control"? It's not a dig, I'm just curious.

http://billpentz.com/woodworking/cyclone/Index.cfm#Motivation
"As a senior engineer and university engineering instructor who specialized in designing air quality test equipment and invented much of the technology now used world wide for smog control I knew the importance of good dust protection."

Will Blick

01-02-2008, 1:49 PM

Bill, thanks for the very informative post. A few questions if you would be so kind....

After all you have been through, I am curious, if you had this knowledge many years ago before you started wood working.....would you avoid it as a hobby as a result of knowing all the potential health risks associated with dust?

You mentioned the use of respirator while working with wood in your ww history. Wasn't this sufficient protection to avoid dust related health problems? Or did you use it too infrequently? It seems even back then, you took many precautionary measures, probably even more than most ww's do today. Can you elaborate on this?

You mentioned an analogy of cigarette smoking and fine dust inhalation - some people react to each, but not everyone. It's clearly obvious that cigarette smoke is a lethal habit, at best, some people have a better immune system than others, to hold off the smokes damaging effects. Also, cigarette smokers vary greatly in their total intake, as some only smoke a few cigs a day, while others smoke 3 packs a day. This makes me very curious about something which I hope you can offer us your opinion.....

Since your crusade began awhile back to help other ww's, it seems you have become the clearing house for information regarding wood dust (even though you never volunteered for this position) - both the proper collection of dust, and how it has effected ww'ers health. I am sure many people who are suffering from wood dust health problems have communicated with you over the years....some looking for help, some just to share stories, maybe you have researched these workers health patterns, longevity etc. So you are probably have as much knowledge as anyone in this area, partly due to the ease of communications via the internet, which you have utilized very well.

My question is, in general, would you say that fine wood dust has proven to be lethal in those with max. exposure vs. the weekend warrior? There is many who work in the ww field who are exposed to dust 12 hrs a day for decades, vs. the weekend warriors that may be exposed to dust 12 hours a month. From your experience (and I realize this may be your gut reaction, not solid science), do you feel most of the dust related health problems are associated with those exposed for decades? Or do you find that many weekend warriors also have a surprisingly high incidence of dust related health problems? I am curious if the problems occur most often to people who have a pre-disposition to dust, vs. continued long-term exposure.

Also, you mention the problem with certain toxic woods. Do you feel people working with these woods represent a high % of those with serious dust related health problems today, or would you lean more towards those who have had max. exposure to even the less toxic woods?

Again, I realize some of your response may be your gut feeling, accumulated from your research and working /communicating with so many ww'ers. But like all fields in their infancy, sometimes, these gut feelings are the seeds that bear fruit in the years to come. It's all we have to get a better understanding of the problem. Of course, we all know that each of us reacts differently, so my questions are of a generic nature.

After reading about the serious health problems the grain workers suffer, it set off some alarm bells in my head. Considering their dust inhalation is from the same foods they eat, it clearly demonstrated that the source of the dust does not need to be toxic itself to cause serious health problems. Which leads me to believe, as you have mentioned, it appears to be more a function of dust particle size, rather than the dust source...... within reason here, I am sure nuclear waste dust will have a more lethal effect than what we are discussing here.

Sorry for all the questions..... and thank you again for being so generous with your time and expertise to help many of us better understand what you have learned through your tireless work in this area.... IMO, you are a pioneer. I find your opinions insightful and help me get a better grasp on ww as a hobby for me. I don't feel I am being overly paranoid, but I like to make informed decisions with as much information as possible.

And btw, thanks to you, I have already implemented many drastic measures to limit my dust exposure, such as using a cyclone vented outside, dust masks, better tool collection, opening the doors whenever possible, installing a continuous exhaust system with make up air coming from the other side of the building, using less toxic woods as often as possible, doing much less hand sanding, using downdraft tables when i hand sand, etc. Of course, all this seems so obvious now, but before I digested all your information awhile back, well..... my approach to ww was just, get the job done, health risks was not on my mind. So your hard work and your generosity to share your data has altered my approach and mindset to ww in a very favorable manner. So, thanks again Bill.

John Hain

01-02-2008, 2:35 PM

Bill,

I for one, want to thank you again for the work you are doing in this area. You might remember, we talked on the phone about a year ago about DC systems as well as fine sanding applications. Needless to say, I took all your information to heart and have followed through as recommended. My work environment is much more safe, due in no small part to your assistance.

As a surgeon and woodworker, I urge you to continue your work. There will always be a few individuals who question your work and attempt to undermine your efforts and knowledge base.

Your efforts have not gone unnoticed!

P.S. My children and wife thank you too. They breathe the same air as I do!

John Hain

Chase Gregory

01-02-2008, 5:13 PM

It sounds to me like flinging my 8x8 barn door open and cranking up the portable 36" belt drive fan isn't such a bad idea after all!

Of course I've been doing that primarily to overcome the totally pulverized dust from a 60 year old dirt floor...

This is the kind of dust that doesn't even need air movement...it will rise when the barometric pressure drops!

Chaser

Bill Pentz

01-02-2008, 6:19 PM

Hank,

…I just have a question for Bill, what company were you a senior engineer at when you "invented much of the technology now used world wide for smog control"? It's not a dig, I'm just curious…

Hank,
In my past I worked with UC Davis to build a smog monitoring system. I also had a background with automotive repair owning part of four different shops. I was serving with the State of California, Office of Procurement as their lead responsible for oversight and writing technical engineering specifications for the purchase of office automation, network, and personal computer equipment. That combination of skills and a pretty good track record of success got me drafted against my wishes into the Bureau of Automotive Repair with responsibility to take over the development of a new Smog Check emissions analyzer. All of the senior engineers had already left that organization over management conflicts. They already had the test portion of the new analyzer designed but had hit a wall in designing the computer portion and securing that analyzer against tampering. I designed the computer system and programming specifications and helped build a working prototype for the BAR-90 vehicle emissions machine. That machine is now the world standard except here in California where we now use a newer dynamic tester.

Bill, thanks for the very informative post. A few questions if you would be so kind....

After all you have been through, I am curious, if you had this knowledge many years ago before you started wood working.....would you avoid it as a hobby as a result of knowing all the potential health risks associated with dust?

Will, I was raised by a father who as a woodworker insisted on making most of our own furniture and building our own homes, plus I dearly enjoyed my woodworking taking every class and opportunity I could get to improve my skills. As my career advanced and I left the family construction business I went from being able to see the fruits of my labor to management and overseeing big projects that were so huge I almost never got that satisfaction of being able to say “I built that”. I filled that void becoming a hobbyist woodworker making “special” gifts for family and friends. So I would still have pursued woodworking without a second thought.

You mentioned the use of respirator while working with wood in your ww history. Wasn't this sufficient protection to avoid dust related health problems? Or did you use it too infrequently? It seems even back then, you took many precautionary measures, probably even more than most ww's do today. Can you elaborate on this?

What I did wrong was wore my respirator only when making fine dust. I had no clue that the most dangerous dust, the 10-micron and smaller particles which are invisible without magnification had built up so high in my clean looking shop from venting my cyclone inside that I was getting dangerously high exposures even when not making fine dust. My medical air quality test run after three months of no woodworking showed just turning on my cyclone without doing any woodworking launched enough fine dust mostly from the cyclone filter to fail the air quality test. I needed to wear my respirator mask any time I worked in my shop, or come up with a far better dust collection system.

You mentioned an analogy of cigarette smoking and fine dust inhalation - some people react to each, but not everyone. It's clearly obvious that cigarette smoke is a lethal habit, at best, some people have a better immune system than others, to hold off the ill effects. Also, cigarette smokers vary greatly in their total intake, as some only smoke a few cigs a day, while others smoke 3 packs a day. This makes me very curious about something which I hope you can offer us your opinion.....

Since your crusade began awhile back to help other ww's, you have become sort of a clearing house for information regarding wood dust - both the proper collection of dust, and how it has effected ww'ers health. I am sure many people who are suffering from wood dust health problems have communicated with you over the years....some looking for help, some just to share stories, maybe you have researched these workers health patterns, longevity etc. So you are probably have as much knowledge as anyone in this area, partly due to the ease of communications via the internet, which you have utilized very well.

My question is, in general, would you say that fine wood dust has proven to be lethal in those with max. exposure vs. the weekend warrior? There is many who work in the ww field who are exposed to dust 12 hrs a day, vs. many weekend warriors that may be exposed to dust 12 hours a month. From your experience (and I realize this may be your gut reaction, not solid science), do you feel most of the dust related health problems are associated with those with life long continuous exposure? Or do you find that many weekend warriors also have a surprisingly high incidence of dust related health problems?

Whew, thanks for the kind words of support. My respiratory doctor has specialized in allergic reactions for more than thirty years. He answered this same question for me when he was pushing me to put up my web pages. He said rarely is wood dust lethal, but he believes it is responsible for a far higher percentage of allergic reactions and illnesses in older people than most realize. He explained that just about any amount of woodworking is going to make far more fine dust than it takes to create a problem. Although we see immediate toxicity problems and allergic reactions, the permanent damage to our lungs ends up appearing later in life. It is very hard to tie to woodworking to many elderly problems because the damage is done years if not decades before. We know from medical studies that every fine dust exposure creates some small permanent damage and this damage accumulates with time and amount of exposure.

He said the biggest problems seem to happen to small shop and hobbyist woodworkers because we have much higher exposures than woodworkers who work in larger facilities. He explained most in commercial shops are subject to fire marshal inspection that requires placing most large commercial dust collectors and cyclones outside where the fine dust is blown away. This is not so for the 6 out of 7 professional and hobbyist woodworkers who work in small shops. We tend to vent our dust collection inside. We also have problems because most of our tools come with hoods that spray fine dust all over; most small shop dust collection systems move about half the air needed for good fine dust collection; and most small shop filters in spite of advertising claims pass a good portion of the fine 10-micron and smaller invisible particles known to cause the most long term damage. These fine particles get right by our bodies’ natural protections then lodge in our tissues were we have a difficult time getting rid of them. Our indoor filters should be rated when clean and new as required by ASHRAE. Instead our vendors rate the filters based on having a cake of dust built up in the filter matrix that does not come out with normal machine shaking or pulse jet cleaning. Also, most small shop wood workers so obsessively clean our filters that they rarely “season” enough to provide the vendor advertised levels of protection. While our filters "season" and after every over cleaning we are left with our lungs doing the filtering. Worse, because this fine dust is so easily transported in any shared air and on our clothes, skin and hair we end up contaminating all areas we visit. Our normal heating and air conditioning filters in our homes just keep cycling this dust as it builds leaving us and all close to us with high exposures.

Also, you mention the problem with certain toxic woods. Do you feel people working with these woods represent a high % of those with serious dust related health problems today, or would you lean more towards those who have had max. exposure to even the low toxic wood species?

Most of those who have shared with me that they have developed problems are those who either have long worked in dusty shops or had high exposures to one of the more toxic woods. Unfortunately, we all react differently to the many woods that can cause us to quickly build up a sensitivity. Take a look at the Toxicity Table (click here) (http://www.billpentz.com/Woodworking/cyclone/WoodToxicityTable.cfm) I updated and share on my pages

Again, I realize some of your response may be your gut feeling, accumulated from your research and working /communicating with so many ww'ers. But like all fields in their infancy, sometimes, these gut feelings are the seeds to future fruit. It's all we have to get a better understanding of the problem. Of course, we all know that each of us reacts differently, so my questions are of a generic nature.

After reading about the serious health problems the grain workers suffer, it set off some alarm bells in my head. Considering their dust inhalation is from the same foods they eat, it clearly demonstrated that the source of the dust does not need to be toxic itself to cause serious health problems. Which leads me to believe, as you have mention, it's more a function of dust particle size, rather than the dust source...... within reason here, I am sure nuclear waste dust will have a more lethal effect than what we are discussing here.

From what I have read we have three basic problems with wood dust. First are the chemicals found in wood which can be poisonous, irritants, sensitizers or increase our risk of cancer plus cause a few known diseases. Second are the chemicals often associated with woodworking. Wood often contains chemicals from glues, solvents, finishes, resins, insecticides, herbicides, preservatives, etc. Likewise when molds, yeasts, fungi, mildews, lichen, etc. break down wood they also add additional chemicals to our wood dust. The larger the particles the more of these chemicals in the wood dust we take in, so the greater the risk. The third area has to do with the long term damage done to our respiratory systems by the fine dust. We know that all kinds of fine dust are pretty unhealthy with 5 to10-micron sized particles lodging in our respiratory passages where our bodies have a hard time getting rid of them. The 1 to 5-micron sized particles lodge in our lungs with the particle material (PM) sized 2.5-micons and smaller well known to cause long term lung fibrosis and related problems. I think what makes this most dangerous is understanding that hand sawing less than 7” of ¾” stock creates enough fine dust to cause a typical 2-car garage sized shop to fail and OSHA air quality test, cause five of these same sized shops to fail an ASHRAE air quality test, and cause fifty of these same sized shops to fail a medical air quality test of only 0.1 milligrams per cubic meter of air (mg/cm3) which is the latest EPA standard and for outside air would trigger a serious smog alert.

Sorry for all the questions..... and thank you again Bill for being so generous with your time and expertise to help many of us better understand what you have learned through your tireless work through the years.... I know for me, I find your opinions insightful and might help me get a better grasp on ww as a hobby for me. I am not being overly paranoid, but I like to make informed decisions with as much information as possible.

And btw, thanks to you, I have already implemented many drastic measures to limit my dust exposure, such as using a cyclone vented outside, dust masks, better tool collection, opening the doors whenever possible, installing a continuous exhaust system with make up air coming from the other side of the building, using less toxic woods as often as possible, doing much less hand sanding, using downdraft tables when i hand sand, etc. Of course, all this seems so obvious now, but before I digested all your information awhile back, well..... my approach to ww was just, get the job done, health risks was not on my mind, so your hard work and your generosity to share your findings with us, has altered my approach and mindset to ww in a very favorable manner. So, thanks again Bill.

You are most welcome

It sounds to me like flinging my 8x8 barn door open and cranking up the portable 36" belt drive fan isn't such a bad idea after all!

Of course I've been doing that primarily to overcome the totally pulverized dust from a 60 year old dirt floor...

This is the kind of dust that doesn't even need air movement...it will rise when the barometric pressure drops!

Chaser

My doctor eight years ago said most small shop woodworkers would be a lot better off if they would always wear a good fitting dual cartridge respirator mask and run a big fan in that open doorwaywhile making fine dust. I think you said the same thing. In my running all over the California a year ago testing air quality in various shops, those who had the least residual dust problems were not those with the most expensive dust collection systems, but instead those who kept a good sized fan blowing in an open doorway.

Bill,

I for one, want to thank you again for the work you are doing in this area. You might remember, we talked on the phone about a year ago about DC systems as well as fine sanding applications. Needless to say, I took all your information to heart and have followed through as recommended. My work environment is much more safe, due in no small part to your assistance.

As a surgeon and woodworker, I urge you to continue your work. There will always be a few individuals who question your work and attempt to undermine your efforts and knowledge base.

Your efforts have not gone unnoticed!

P.S. My children and wife thank you too. They breathe the same air as I do!

John Hain

Dr. Hain,

Thank you for your kind words of support. Frankly, you and the many other doctors who continue to not just support my efforts but also give me a once in a while needed kick in the pants are one of the main reasons I keep my web pages up. You may recall that I quit in August of 2003 and pulled my web pages down. I was tired of the many who attacked because they did like me and spent lots on impressive looking dust collection systems that seemed to them to work great. I was even more tired of vendors that I helped so much actually paying people to attack me personally and belittle my efforts on most of the woodworking forums. I also was exhausted from the amount of work which not only was taking in excess of four hours a day, it was costing me an average of over $10,000 a year to keep my Cyclone and Dust Collection Research (http://www.BillPentz.com/Woodworking/Cyclone/Index.cfm) web pages going, continue my testing of dust collectors, cyclones and filters, plus continue to design and refine solutions to help other woodworkers avoid the health problems that snuck up on me.

I did not quit and hope within the next week or so to release a whole new set of pages that should be far easier to read and follow.

Wishing all a happy, healthy prosperous New Year.

bill

Bill Lantry

01-02-2008, 7:35 PM

Dear Bill,

I just want to take a moment to add to what others have said. Your work changed my whole approach to woodworking. No, my system is not yet where it should be, but I'm further along in dust collection than I would have been without your efforts. Thanks for all the time and trouble you put into this, and please don't get discouraged by a few naysayers... ;)

Thanks,

Bill

Tim Marks

01-02-2008, 8:42 PM

No, your statement is not accurate. I have two engineering degrees, and a general education college degree that I never bothered to pickup...
Sorry, my mistake. Which engineering degrees were those and where and what year did you get your diplomas? You should really update your website; you can understand how I got confused when I read the following:

With units and course work ample to get minors in pre-medicine, engineering, biology, chemistry, physics, organic chemistry, philosophy, psychology, and art, UC Davis offered me a certificate in general education. I only needed a few engineering classes for my bioengineering degree but they would not let me back in. Distraught and bitter over the whole experience, I ignored that offer failing to pick up that general degree...

Sadly, there were some technicalities imposed by the Legislature that forced me to go back and take advanced ethnic studies before my BS work would be completed. Without that BS in hand, it turned out that in spite of a 3.9+GPA in my master's courses, I could not legally take credit for them. After years of frustration trying to get the degree I earned, I finally gave up and just claim it.

http://www.billpentz.com/educate.htm

Chuck Tringo

01-02-2008, 9:05 PM

Well, as a big DC system of any style is not in my budget right now, ill keep working with the garage door open and my respirator on. I can afford a better fan, i think ill get one of the big industrial style ones as soon as i get back in the shop. I do have a Steel City air cleaner that I run whenever im out there and for about an hour or two longer than I work, and it is posted right before the door, as i hope to catch as much dust as possible before it goes into the house.

Will Blick

01-02-2008, 9:22 PM

John Stevens

01-02-2008, 9:53 PM

Bill Pentz wrote: "He explained that hand sawing less than 7” of ¾” stock generates enough fine dust to cause a typical 2-car garage sized shop to fail an OSHA air quality test."

This is not a dig at anyone--not Bill Pentz, not the expert he quoted, and not even OSHA. But it seems to me in comparison to the example given, most people are exposed to fine dust in far greater concentrations on a regular basis. Can you imagine how much fine dust is inhaled by the average person who sweeps, vacuums and dusts the house each week? Anyone who has sifted flour, bailed hay, raked fallen leaves, worked in a greenhouse, emptied trash cans, sat in a tavern, or ridden on unpaved roads has inhaled clouds of fine dust, sometimes for hours on end. And yet almost none of us show any adverse effects from it. I think this shows that comparisons with the OSHA standard are of limited utility in gauging health risks associated with exposure to fine wood dust for otherwise healthy people.

Regards,

John

Ken Baker

01-02-2008, 10:16 PM

Bill - I personally want to thank you for the information on your website and the postings I have read on this and other forums. None of the naysayers seem to have their own websites - it's very easy to criticize, but much harder to do something about it. As mentioned above - I'm sure there are countless people who have benefited but don't come forward.

When I got back into woodworking last year I had the means to afford better stuff and I avidly read every page on your site and used it as the baseline for my dust collection system. I bought a clear vue cyclone and am running 6" lines as far as I can. I built a shed oustide to house the unit so I don't have to worry about which filter is best for the return air.

I personally don't care "who invented what - and who gets the credit" - You sir get the credit for compiling all the information into one cohesive website.

If you are ever in Orange County I would be honored for you to visit and critique my shop and offer any suggestions that improve my chances of living a life that is not cut short from microns of dust.

Bill Pentz

01-03-2008, 12:33 AM

... What full face powered respirator would you recommend? I have strongly considered the 3m Adflo, what is your thoughts on this respirator? It seems ideal for ww'ing?

Will,

On my Doc's Order's pages you will see I am not a big fan of powered respirators. I really disliked rushing projects because my powered respirator batteries kept dying. Although we have much better batteries today, for most I still think a good 3M model 7500 respirator mask in the right size is plenty. For those who turn, it is nice to have a powered respirator with protective face shield. Many of my wood turner friends swear by the old Racal PAPR units with the belt mounted battery pack, filter, and blower. Those stopped being made when 3M bought up that technology. I see the near identical current 3M models similar to the 3M Adflo can set you back $1000+ dollars. Today you can buy the Trend Airshield, a very similar powered respirator that most like. I use one of the older Racals with a mix of 3M stuff, plus have a Triton.

Tim Marks

01-03-2008, 7:31 AM

Thanks Bill. Your webpage update clears up some confusion about your missing degrees.

Looking at your cyclone modification, I guess I missed that you are really advocating a 1D1.64D instead of a 1D2D that others in industry said were most efficient. I bet you got good at cutting up sheetmetal before you came up with that answer.

Since this 1.64D dimension is really based upon making a cyclone that first under a typical ceiling, if someone had unlimited ceiling space or were scaling this design down to a vacuum sized dust collector, would they be better off using the more typical 1D2D or 1D3D design then your design?

Laymens terms: a 1D2D cyclone size related the diameter (D) against the upper body and lower cone. A 1D2D cyclone with an 18" diameter would be 18+36=54". Add a barrel on the bottom and a blower on the top, and you would have to cut a hole in the ceiling.

One of the other critical dimensions is the inlet size. A typical cyclone is specified with a rectangular inlet of D/4 wide and D/2 tall. Since most people run 6" pipe at least, wouldn't it make sense to scale the cyclone off that dimension (if you have room). So that would ,make an inlet 12x6", a diamter of 24", and a cyclone height of 24+40". With your chosen cyclone diameter and the resulting required size of the inlet duct, wouldn't that tend to choke flow?

Bill, have you ever tried to feed back the critical data you found to some of the cyclone experts in the agricultural field (Wang, Parnell)? I have not seen the 1.64 number referenced anywhere else.

Art Mann

01-03-2008, 8:43 AM

. . . for most I still think a good 3M model 7500 respirator mask in the right size is plenty.

I noticed from your photo that you have a beard. Well, so do I. I use a similar mask for high risk operations like spraying, sanding and cutting MDF. I was wondering just how much dust makes its way around the mask through the beard.

Phil Thien

01-03-2008, 9:34 AM

I noticed from your photo that you have a beard. Well, so do I. I use a similar mask for high risk operations like spraying, sanding and cutting MDF. I was wondering just how much dust makes its way around the mask through the beard.

Depends on the beard. I strongly suggest you upgrade to a 1-micron type. HEPA beards are nice but too scratchy. :p

Thom Sturgill

01-03-2008, 10:01 AM

Bill,
Thank you very much for your work. I have lost family to lung cancer and personally have a heart condition that makes me sensitive to breathing issues. I currently work in a Florida garage and keep the large door open with a fan blowing from behind me and wear a mask (most of the time). I also have a HF DC that I will be buying a Wynn filter for. When I retire in a few years I hope to move back to NC mountains and build a shop there, and if I want to work during the late fall/winter/early spring I will have to close the shop and heat it.

I have seen a lot of comments about the issue of venting outside and heat loss, since the high CFMs required can totally exhaust the air in a small shop in a few minutes requiring considerable make up air. This becomes a major issue in a heated/air conditioned space. I know that air heat recovery ventilators exist, but residential units are sized for much lower CFMs (2-300). Has any work been done on incorporating heat exchangers into dust extraction systems? To what result?

Eric Haycraft

01-03-2008, 10:32 AM

I have a small shop in a tucked under (currently unheated) garage. It is hovering around 10 degrees outside now in MN and venting outside or leaving the garage door open doesn't seem like a good option.

Has anyone rigged up a dust collector with an air to air heat exchanger so that they can vent outside and capture most of the heat loss? If so, are there any ways to do it on a budget and is it that much better of an option than venting inside?

Thanks,

Eric

Phil Thien

01-03-2008, 10:55 AM

Has anyone rigged up a dust collector with an air to air heat exchanger so that they can vent outside and capture most of the heat loss? If so, are there any ways to do it on a budget and is it that much better of an option than venting inside?

Thanks,

Eric

Oooh. That is a good question that I have wondered about myself. Can't imagine why it wouldn't work.

Art Mann

01-03-2008, 11:40 AM

Depends on the beard. I strongly suggest you upgrade to a 1-micron type. HEPA beards are nice but too scratchy. :p

No chance of that. My beard is the consistency (and appearance) of coarse steel wool. :(

Bill Jepson

01-03-2008, 11:46 AM

Bill, thanks for taking the time to answer my questions so thoroughly.... you cleared up several issues.

you wrote...

> I think what makes this most dangerous is understanding that hand sawing less than 7” of ¾” stock creates enough fine dust to cause a typical 2-car garage sized shop to fail and OSHA air quality test,

I have read where you wrote this before, and you are right, this statistic is shocking..... it really demonstrates how much fine dust is created doing the most simple task....wow... I may have a different outlook from this point forward on how many projects I decide to tackle.

What full face powered respirator would you recommend? I have strongly considered the 3m Adflo, what is your thoughts on this respirator? It seems ideal for ww'ing?

As for your comments regarding people bashing you on these forums. IMO, for every person who attacks you senselessly, there is probably 500 people who really appreciate your contributions to the ww community. It's unfortunate more supporters don't post regarding these unwarranted attacks.....its just the nature of forums in general. I find SMC is well moderated, unlike others such as woodnet where the pile-ons are so ridiculous, it borders on insanity. So maybe, its best you pick and choose your forums carefully. Also, thanks for the web site. If you ever decide to publish a book, put me on the list.

Bill P, Will is correct, few people who are satisfied with your system will comment. Those harping about qualifcations should be spending the money and doing the blasted test themselves then, AND posting their results to be criticized. I believe one of the most CRITICAL items that you have brought to light for the hobbyist woodworker is that the most critical particles to catch are those that can't even be seen by the avrage person. I truly thank you for that. I was aware of these kind of problems having done some automotive painting. In that kind of painting even vapors are dangerous. The auto paint industry goes so far as to recomend an external air source. Either forced air or the equivilent of a scuba tank!
Are different people effected differently, well YES. Are there different levels of exposure that will effect people adversly, of course. The fact that started Mr. Pentz campaign for awareness may have been his own unfortunate sensitivity. The vital point he brings though is that many of the problems that arise from particulate contamination are cumulative. Once you have been sensitized YOU ARE DONE. There is no back or escape key on your lungs. If you are like the little 102 year old guy we see on the news that lived to that ripe old age while drinking and smoking every day, fine. Just remember not eveybody is so lucky. I don't know Bill Pentz but I have visited his web site, which I consider well reasoned and accurate. Remember he posted the plans to his version of the cyclone DC FOR FREE!
The attitude of the people sniping at him is foolish at best. He isn't trying to legislate that you have to use his system, just informing you as to the dangers inherent in what we do.
I really can't understand the resistance to advancement in shop safety. I didn't like the Saw Stop legislative efforts, but to naysay the PRODUCT doesn't make sense. It is a excellent idea that has already saved a lot of peoples fingers. I believe Mr. Pentz has, do to his own unfortunate circumstances, been forced into doing a better job of dust collection. The fact that he has offered the info he's learned FREE to the rest of us deserves a medal, not critics. My $0.02.
Bill Jepson

Will Blick

01-03-2008, 12:59 PM

Bill J, EXCELLENT post!!!! I could have not said this better myself, thank you...

Bill P, I understand your issue regarding battery life for powered respirator, but the adflo can run 8 hrs, more than I would use it for in a day.... and it offers both organic vapor cartridges as well as dust cartridges which can be piggy backed, specially for cutting MDF. Since I want a protection from finishing and dust, and I don't have a beard...... do you see the benefit better? The Trend does not offer organic filters, so its dust control only.

The other benefit of a powered respirator is, you don't have to slam the respirator to you face to create a super tight seal like you do a manual respirator (to prevent leaks). The pressure on your face is annoying, and many of us suffer from "scuba mask headaches" from the continuous pressure on our face.

I do use a half face manual respirator. My other big problem with them is, its hard to wear safety glasses, as the nose seals come up so high, there is no place to sit the glasses on your nose.

Any thoughts?

Walt Nicholson

01-03-2008, 1:09 PM

Bill Jepson

01-03-2008, 4:33 PM

I have never been the sharpest knife in the drawer but has any group or organization done a definitive study of the long term effects of sawdust on woodworkers nationwide? Years ago studies were done about the number of people who died of "black lung" disease from coal mines, and the number of deaths and problems from asbestos and paint in automobile paint booths, but I have never seen anything about woodworkers. I know some people who could probably eat poison ivy for lunch and never be bothered and others who go into hiding when the pollen is around in the spring, so it is natural to expect some people to have allergic reactions to some (or all) types of sawdust. Here in the northwest we have had many, many mills in operation for years with more sawdust in the air than you can imagine but no epidemic or widespread indications of lung disease or sawdust related deaths. I also know that you can violate OSHA standards if you paint a railing the wrong shade of yellow. I can remember my grandmother using a broom to dust the sawdust off of us kids after we had been watching grandpa work in his wood shop. He died of old age at 89. My dad followed in his footsteps and died of old age at 91. I feel worse physically sitting at a stoplight and breathing the diesel fumes from the truck in front of me than standing in my shop smellling the sweet smell of fresh cut wood. I may be too old and stubborn (and dumb) but I will die happy, covered in sawdust, before I will subject myself to working in a sterile, "clean room" environment with hoods and respirators and such like some nuclear facility as some people in these posts advocate. I have a Delta ceiling mount filter and a good DC setup and call that good for me. Now I will quit my rant and go make some more sawdust. Just an opinionated old fart.

Walt,
There have been a number of studies about people working in lumber mills getting "brown lung." ANYONE who works continuously in a high particulate atmosphere will have problems unless they protect themselves, period. This seems sort of obvious now. People will react at various levels. Some will simply be mildly irritated, and others will need to avoid the activity altogether. Everybody has heard of some elderly person that has smoked since they were 15 and they lived to 93. But then a BUNCH died of lung cancer at 54 too. The problem is that we should inform people, without rancor. If you chose to use a resperator great. If you don't it is YOUR choice. The problem is that many sensitivities build up over time. When you see the first problem you are already done and there is no going back. You then face a risk every time you do the projects that you enjoy. Currently no one would argue that hearing loss is cumulative, they simply KNOW that it is. If you work continously in a 100 decibel environment without hearing protection you WILL go deaf. Heck check out all the old rockstars sporting hearing aids! If you do occasional WW you probably won't have the level of problem Bill Pentz had. On the other hand, you might. I'm no nervous ninny, I used to race motorcycles so I can't be overly safety concious! But telling people what MIGHT happen and letting them decide if they want to take action is a flat out GOOD IDEA. Showing them how to minimise their risks is an EVEN BETTER IDEA! Thanks Bill Pentz for being the torch-bearer on this one.
Bill Jepson

Walt Nicholson

01-03-2008, 6:33 PM

I appreciate your input and you have some very good points. I agree that it is good that we are informed of the dangers that face us in the shop although there seems to be varied opinions in this forum as to the amount of the danger and to the credentials of the people defining the danger. That is why I asked if there were any definitive (clinical) national studies done that document deaths and illness related to woodworking/sawdust. I had not heard of the Brown Lung disease that you mentioned and would like to learn more. When I googled it I got "Byssinosis (brown lung disease) a chronic condition involving obstruction of the small airways, severely impairing lung function. It is caused by dust from hemp, flax, and cotton processing. Between 1979 and 2002 byssinosis caused approximately 140 deaths." I will continue to look further for the association with sawdust as I do want to learn. I do not argue the obvious point that inhalation of any foreign substance into the lungs can be harmful and the people that are trying to prevent or reduce that inhalation are to be applauded. I guess I was just looking for case studies in lieu of opinions that would document the severity of the risk so that I could make a more informed decision as to the trade-offs between all out security and the enjoyment of the hobby. I certainly meant no disrespect to any member of the forum and their opinions.

Rick Moyer

01-03-2008, 8:28 PM

... But telling people what MIGHT happen and letting them decide if they want to take action is a flat out GOOD IDEA. Showing them how to minimise their risks is an EVEN BETTER IDEA! Thanks Bill Pentz for being the torch-bearer on this one.
Bill Jepson

Well said Bill. I think this is what we really need to be thinking about when we read what Bill Pentz has to say. Many folks may think Mr. Pentz is "preaching" to them and get defensive. (maybe he is!??). We are each free to decide what is best for us, but we cannot make good decisions without some knowledge base for making those decisions. Everyone can chose to do or not to do what someone else might recommend,; but isn't it better to make your decision having a wealth of knowledge that someone has provided you? Kudos to Bill Pentz for providing it so I can make an informed decision for myself.

Bill Pentz

01-03-2008, 10:20 PM

Your webpage update clears up some confusion…

Tim, I appreciate your questions but found that getting into the kind of detail you are asking for on a forum ends up in overwhelming amounts of detail that few hold of any interest, plus buries me in far more typing than I want to do. If you want to call or have me call you I would be happy to go over some of the detail that led me to creating a 1D1.64D cyclone design. In very lay simple terms my target was not just fitting my cyclone design under an 8’ ceiling but instead providing minimum airflow resistance and maximum fine dust separation. If you go to the ESSCO spreadsheet you mentioned, plug in a 4000 FPM airspeed which the minimum to pick up most sawdust and smaller chips and an 800 CFM air volume which is just about the minimum to get good fine dust collection at our stationary tools, that optimizer will spit out a cyclone that is about 13.5” in diameter powered by a whopping 7.5 hp motor. We can trade fine dust separation efficiency by expanding the sized of the cyclone diameter (D). The Cotton Research shows making D three times the main that feeds the cyclone is near ideal. So a 6” duct would make an 18” cyclone. Those with 7”, 8” and 10” cyclone inlets should be making 21”, 24” and 30” diameter cyclones. These will not fit under a standard 8” ceiling so they instead make smaller cyclones and increase impeller diameter and motor sizes. Anyhow, this all gets so messy that it is hard to cover in brief posts.

I noticed from your photo that you have a beard. Well, so do I. I use a similar mask for high risk operations like spraying, sanding and cutting MDF. I was wondering just how much dust makes its way around the mask through the beard.

Art, Yes I have a beard and it does cause some leakage but probably not as much as most as my hair is very fine and most has already fallen through going from the top of my head and out my nose, hands, ears, etc. Seriously, I pull my mask extra tight whenever making just a little fine dust or doing a little painting or spraying. It still leaks more than I want, so when making more than a little fine dust I end up wearing either my 3M or Racal Powered Air Purifying Respirator (PAPR). Both are near identical except my 3M also came with a second flip down welding mask visor option. Given Racal stopped making their units and the 3M are pretty pricey, for most I recommend that 3M 7500 unpowered respirator mask unless they are turners, have a heavy beard, or developing some sensitivities. My turner friends like the Trend Airshield powered respirators that work great with beards becase the air just gets blown out through any leaks instead of us sucking stuff in. That new Trend Airshield Pro is a near exact copy of my far more expensive 3M and I would like to hear when people begin buying these how well they work. Also, becareful what you buy has easy to find and affordable filters. I have a new off brand mask whose maker went under and you can no longer get its unique fitlers. Now if Phil would just share with us hairy guys where to get those HEPA beard filters…

I have a small shop in a tucked under (currently unheated) garage. It is hovering around 10 degrees outside now in MN and venting outside or leaving the garage door open doesn't seem like a good option.

Has anyone rigged up a dust collector with an air to air heat exchanger so that they can vent outside and capture most of the heat loss? If so, are there any ways to do it on a budget and is it that much better of an option than venting inside? ...

We move about the right volume, but our airspeeds tend to be pretty high so need a big unit. I asked one of my friends in the HVAC business and he ran some calculations and said most of the larger home heat exchangers would work well, or we could build one ourselves without too much pain. I don't know of anyone who has made one, so don't know how well they would work.

Bill J, Will, Walt & Rick, Thanks for your positive comments.

Walt,

Dust collection studies are a mess. There is really big money involved, plus a huge liability issue. There were peer reviewed medical studies in the fifties that linked long term dust exposure to a variety of problems. Since then we have far more information. These studies are pretty clear about the invisible without magnification 10-micron and smaller particles. A 10-micon particle is about one tenth the thickness of Art’s coarse beard hairs. The chemicals in and associated with wood cause specific problems for the particles all the way down. Those particles sized about all 2.5-microns and smaller have the added issue of causing serious long term major problems just from their size and shape. These are so well studied they now have their own shorthand name PM short for particulate material. Do a Google search on "PM 2.5 Health Risks” (http://www.google.com/search?q=pm+2.5+health+risks&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1) and you will see a load of credible studies that point out just the concerns from general particles of this size. I’d start my reading with the EPA discussion (http://www.epa.gov/pmdesignations/faq.htm)that defines what these are, explains the sizing and some of the other basics. Also, spend a little time looking over my Wood Toxicity Table (http://billpentz.com/woodworking/cyclonenew/WoodToxicityTable.cfm)to see some of the dangers from the chemicals from wood particles.

bill

Abe Low

01-04-2008, 12:54 AM

I have been aware of the dangers of fine particles for several years before I met Bill. Bill has done wonders to spread the word in a way that makes the data believable. Everyone has the right to stick their head in the sand or believe that "I will be fine until it is my time". But it is a good thing to have the knowledge made available. If one is going to deny the evidence they ought to at least see the evidence.
Thank you Bill for being my Hero.
Btw, I met Bill for the first time when he was teaching at Sacramento State University in the Computer Science Department. He helped me greatly in preparing me to teach in that same capacity. If I recall correctly, he also taught at the University of California at Davis. At the time I didn't know he shared my love for woodworking. That part of our friendship came much later. Although it doesn't show through in his postings and his web site, he really is a very unpretentious fellow, that in addition to be generous, knowledgeable, and dedicated. Too bad he aint rich and good looking.

Bill Jepson

01-04-2008, 4:46 AM

Bill J, Will, Walt & Rick, Thanks for your positive comments.

Walt,

Dust collection studies are a mess. There is really big money involved, plus a huge liability issue. There were peer reviewed medical studies in the fifties that linked long term dust exposure to a variety of problems. Since then we have far more information. These studies are pretty clear about the invisible without magnification 10-micron and smaller particles. <snip>. Also, spend a little time looking over my Wood Toxicity Table (http://billpentz.com/woodworking/cyclonenew/WoodToxicityTable.cfm)to see some of the dangers from the chemicals from wood particles.

bill[/color]

Bill,
It might help to actually define the size of the particles we are talking about here so people can understand what is involved. I work in the scientific Ultra-High-Vacuum industry making parts for the semiconductor industry, so I understand how small a micron is. For people working in other industries, and the non technical among us, (please note I did not say uninteligent), a micron is 1 millionth of a meter. In inches it works out to a bit under 1/25,000th of an inch. Or Real *&^% Little to use the vernacular. This is NOT regular "sawdust". Visible particles are usually removed by even a moderately good filter. Several of the guys have commented that they have no desire to work in a "clean room". That is perfectly OK. What you need to know is what the guys that put clean rooms together have learned about small particle research. When a particle gets this small it is so light that gravity can be a weak force compared to the smallest air current. Think of sitting by a window in strong sunlight. Ever seen the airborne dust floating around? Ever wondered what kept the dust in the air? The thing to understand is the harmful particles are even smaller than the ones you see dancing in the sunlight. Those are likely to be 10 microns or larger. When someone measures these particles they are in the air floating around even if you haven't been in the shop for some time. Getting the concentration of the particles low enough to be safe is what we are talking about here.
I don't want to lecture any body about this stuff either so I'll sign off now I hope that this thread has been useful to the general woodworking population of SMC.
Bill Jepson

Rick Potter

01-04-2008, 5:31 AM

I have to admit my head spins when reading all the technical information here and in your website, but I keep at it trying to come up with a system I can afford that will pick up better than I have had in the past. I have corresponded with you in the past, and want to remind you of the burrito I owe you, and regret not having the opportunity to meet you when you went to San Diego. You went right past my place. Darn it!!

I sure hope you are planning to write a book about all your testing and research. If so, put me down for a signed first edition. It would be a great help to a lot of us to see all the research, charts, etc., along with pictures and floor plans of shops you visit, with real world information on how efficient various setup were in actual use. Most real testing we see in magazines shows a DC set up with a hose to a single machine. Pretty useless in real world terms.

Show us lots of pictures, floor plans, pipe layouts and sizes. Have a section on various popular brands of machines and the best hood types and sizes to use.

I realize this is a lot to ask of one person to include in one book, but you are the obvious person to write it; respected, great credentials, good with words, and with more personal research than anyone I know of.

Others have written books on this, but they have always seemed incomplete. This is your chance to write THE definitive book on dust collectors for the layman. After all, you are... THE DUSTBUSTER.

Glad you are feeling better.

Rick Potter

Tim Marks

01-04-2008, 8:37 AM

I appreciate your questions but found that getting into the kind of detail you are asking for on a forum ends up in overwhelming amounts of detail that few hold of any interest.
Sorry, just the engineer in me getting out of hand. :DObviously once you scratch the surface, what at first seems pretty simple quickly starts getting incredibly complex. I guess we should be thankful that there are big bucks in agricultural to keep pushing research on cyclones, because obviously little is happening from the woodworking side of the house to promote ongoing research. Thanks for opening the door a little bit on some of the other factors that have to be considered.

There is an increased popularity in vacuum-sized cyclones for use in the shop (with oneida's dust deputy kicking off this product line)? I have seen a number of people posting about the miniature cyclones that they have made using your spreadsheet to proportionately reduce the size. If someone was building this, would you recommend that they use a multiplier of 3 instead of 1.64 to define cone height (since they don't need to worry about ceiling space)? Of course, the resulting product might be a little top heavy...

Dexter Hahn

01-04-2008, 10:22 AM

Hi, I'm new here, lurked for a while and as long as this good topic of dust collection is going, thought I'd jump in and ask for some advice. I don’t do that much WW, but I understand I need good dust collection, and I really don't want to invest the time and space to set up a complete cyclone and duct system, so I was thinking something smaller and moveable.
Bill what is your opinion on something like the Oneida portable?
http://www.oneida-air.com/newsite/portable.php
It has two smaller cyclones that they claim will separate out even sanding dust and a HEPA Filter opt. It looks perfect for what I need and looks better to me than some of the smaller machines with bags on them, I would just like a more experienced opinion. Thanks in advance.

Dex Hahn

Bill Pentz

01-04-2008, 12:43 PM

Tim,

The first portable shop vacuum cyclones started appearing on people's web pages back in the early nineties, so OAS by no means pioneered these units. Jim Halbert shared a fairly nice design with needed parts including stand alone vacuum motor back in about ’98.

In terms of that 1.64 cone length to cyclone diameter ratio, I honestly thought the 3 times cone length would be better until some actual testing was done. The agricultural research showed a 3 times cone length worked best and it does with a cyclone having a horizontal inlet. With a horizontal inlet all the air in the cyclone spins waiting for gravity to pull the dust down. There is so much turbulence in spinning that whole air mass horizontally that airborne dust particles 30-microns and smaller mostly stay airborne. A 30-micron particle is about one third the thickness of a coarse human hair. Tilting the inlet and smoothing the airflow can force the airflow to drop the fine dust. The testing that a number of universities and a few medical schools have done on my design showed its 1.64 cone length to cyclone diameter does a five times better job of dropping the fine dust.

Dexter,

I've seen far too much to be a fan of Oneida Air Systems, so decline to comment.

Bill

Chris Padilla

01-04-2008, 12:51 PM

Bill,

Lemme know when you are in the Bay Area; you can check out the DC I put together when you were partnered up with Mr. CE.... :) Keep up the good work; lottsa folks do appreciate it even if they don't say. It is easier to criticize sometimes than give praise. You are obviously a stubbon man--keep on being stubborn! ;)

Cheers...and Happy New Year!

Eric Haycraft

01-04-2008, 1:12 PM

Bill Pentz

01-04-2008, 5:29 PM

Bill, in your opinion.. for a closed attached garage shop would this be an acceptable solution:

clearvue cyclone ~1000 cfm
2 wynn filters vented inside
100 cfm air to air heat exchanger with intake near DC and blowing from the opposite side of the shop. Setup to maintain slight negative inside pressue (since my garage attaches to my house).
I think that I would rig up the heat exchanger to a motion sensor to always run + add an hour or so of runtime after the garage/shop is empty.
DC dumping directly outside is not an option since I am in a townhouse and have an unheated garage in minnesota. brr.

Any improvements would be greatly appreciated..but I am looking for the best setup that I can find that stays around 2k.

Eric,

My recommendations:

Budget & Once in a While Woodworkers:
(Except those who work indoors or in basements).
Buy and use a good 3M 7500 dual cartridge mask fit to your size face. If you are a turner, have a thick beard, or have sensitivities the Trend Airshield seems to be the best powered respirator available for its price. This mask goes on before you start making fine dust and stays on until you have thoroughly cleaned out your shop. If you come back on following days before you clean up, you need to wear the mask.
Put and consistently use a big fan in an open doorway. That fan goes on and stays on for the rest of the day anytime you make fine dust.
At least monthly open all up wide, put on your respirator mask, turn on the big fan in the doorway, and thoroughly clean out your shop. I’ve used both my air compressor and leaf blower to do this. Then let the shop air settle at least overnight before taking off the mask if you stay in the shop to work.
If a door connects your home to your shop put a bathroom vent fan in your shop that turns on when you turn on your shop lights. This will create enough negative pressure that you should not have big blasts of dust going into your home.
Wear at least an apron and if the dust cloud is going to be thick seriously consider a jumper, scarf and hat that stays in the garage.
Use any decent 1.5 to 2 hp dust collector with a 10’ long 6” diameter flex hose going right to your tools. Even if you neck down right at your dust collector and your tool you will still get better airflow with that bigger pipe.

More serious woodworkers and home shops:
(I think anyone who does lots of woodworking or anyone who does woodworking in their homes or basement shops needs to provide good fine dust collection)

Respirator Mask - Buy and use a good 3M 7500 dual cartridge mask when making fine dust. If you are a turner or have sensitivities the Trend Air shield seems to be the best powered respirator available for its price. This mask goes on before you start making fine dust. If you have good fine dust collection where you don’t see any dust spray from your tools you can then take the mask off. Most of us end up even with good fine dust collection, still have a few tools that just cannot be tamed like my 7” sidewinder. It will throw dust all over the shop. After making fine dust any time you go back in the shop you should wear the mask and keep wearing it when in the shop whether or not you are making fine dust until you have thoroughly cleaned out your shop. The problem is we only need a couple of thimble fulls of previously made fine dust which is easily launched by shop airflows to make our shop air very unhealthy.
Fan – I prefer to always have a fan running in an open doorway when weather permits.
Hoods - Upgrade/add appropriate hoods on your tools. Our hoods need to contain the fine dust while blocking and trapping any airflows greater than about 50 FPM. A 50 FPM airflow is about the speed of a soft breath. If the hoods don't control the dust and breezes, we will have poor fine dust collection even with huge dust collector or cyclone blowers.
Tool Ports - You also will need to upgrade your tool ports. Most tool port sizes are 4" for good chip collection. For good fine dust collection we move more air so need bigger ports. The port size should match the ducting size. A 6” duct drown drop should go into a 6" port and a 7" down drop should go into a 7" port. If you have a machine that has more than one collection port, then the cross sectional area should add up to the area of the down drop. For instance the minimum 6" diameter duct needed to support the airflows needed for good fine dust collection has a cross sectional area of 28.27 square inches. So the areas of our two ports added together shoulld be 28.27 square inches plus or minus about 10%. The following table can help you add up the areas of two different port sizes. The green blocks show the only combinations that will work with 6” ducting.

http://www.billpentz.com/woodworking/cyclone/Images/DuctingSizes.jpg
Ample Air Volume - If you work the resistance numbers and do actual testing, the better Jet and Delta 1.5 and other real 220V 2hp dust collectors will do an excellent job of “chip collection” leaving us with clean looking shops, but these are not ample to do a good job of pulling in the fine dust. If you want the really fine dust collection ample to pass an EPA test (medical recommendation), you need to move 1000 CFM from most large stationary small shop tools. You need either a standard pressure blower that moves 4000 FPM air velocity in our ducts with all 7” ducting going right to each tool, or an oversized impeller that will move 5100 FPM in a 6” duct to provide that same 1000 CFM. I’ve engineered enough extra capacity into my blower designs with the 15” impellers they will handle the 1000 CFM airflows using 6” duct. With this more powerful blower design you get to use the much more available, less bulky, and less costly 6” duct. The fan tables show to get the airflow needed anywhere in a 2-car garage sized shop with 6” ducting show for good fine dust collection against normal 2-car shop pressures we need a 3 hp dust collector or 5 hp cyclone.
Venting Outside

If you live in the country and don’t work with woods like walnut and many of the exotics that are toxic and can kill other plants/harm livestock, blow this whole mess far away from your home and forget filtering.
If you live in a mild climate, just about any 5 hp cyclone with 7” ducting will separate good enough to blow the fine dust away outside without any mess unless you let your dust bin get full. Then all blows right through.
No matter where you live I’d like you to install a valve that lets you blow the fine dust away outside whenever weather permits.
Makeup Air - If you blow outside I suggest at least a 14” diameter or larger air hole or open door/window for makeup air without whistling or chance of sucking carbon monoxide backward from your vents and flues into your shop.

Filtering - If you vent inside you need to filter with a fine enough filter to get rid of the fine dust. Most small shop advertized “fine” dust collector and cyclone filters need months to years to build up enough cake of dust in the filter pores before they will actually provide their advertized filtering level. Meanwhile our lungs get to filter off the fine unhealthiest invisible dust. My respiratory doctor recommends you use filters tested when clean and new as required by ASHRAE for indoor filters. I also recommend protecting these fine filters from massive dust loading by not just using a cyclone, but a finer separating cyclone.

Filter Rating - Those with no known problems can do well with the less expensive 0.5-micron filters. Those who are more concerned or have a history of problems need to wear a good mask when woodworking and should use the 0.3-micron or finer filters. The HEPA standard requires each filter be separately tested and provide 99.97% filtering efficiency on all particles sized 0.3-microns and larger. The cost for individual filter certification is high, so I think buying a good quality filter that uses HEPA grade filtering material is ample.
Filter Games - Most small shop cyclone vendors say you only need to clean your filters every 3 to 6 months. But if you look closely on their web pages they admit their filters pass much larger particles than advertized until their fiilters season. Seasoning means building up a permanent cake of fine dust in the filter pores that does not come out with normal light cleaning. We get up to twenty times larger particles going through a fine filter that is clean and new compared to one that is "fully seasoned". If these filters were outside and the fine dust just blew away this would not be a problem. Instead these filters are indoors and this dust lingers for months to years. Passing most of the finest 10-micron and smaller dust particles until they these filters fully seasoned will let vendors claim high filtering levels and let them sell much smaller filters. The better the filtering level, the large our filter needs to be to avoid too rapidly plugging. These open filters leave us using our lungs to do the fine filtering for the six months to two years it takes for their filters to season.
Filter Cleaning - Worse, most of our filters wear out before they ever fully season. As our filters get dirty the air pressure rises enough to force the fine sharp particles to cut and tear their way through the filter pores leaving us with wide open filters. Cleaning does the same thing but faster. Most small shop woodworkers are a touch obsessive about how well we do things. Instead of a light shake or few taps we pull out 100+ PSI shop vacuum or our 120+ PSI air hose and really clean our filters. One heavy vacuuming or spray down can trash a new set of filters. These high pressure airflows really force the fine sharp particles to tear their way through the filter matrix.
Filter Sizing - Size your filters appropriately whether a bag filter or cartridge. If you read over the filter sizing guidelines and the engineering notes from Donaldson Torit, one of the biggest names in filters in the U.S. if not the world, they recommend a maximum airspeed of “clean indoor air” through the filter of no more than about 10 FPM. We can take our 1000 CFM divide by 10 FPM and come up with a minimal area of 100 square feet of filter. If you dig further into the engineering notes they provide formulas that require us to increase the area based upon what particle loading. With my cyclone design and medical school verified separation levels, we still need about 250 square feet of filter area. With other cyclone designs that put five times as much fine dust into the filters you need a lot more area. Additionally, in the fine print on the Donaldson Torit engineering recommendations, they recommend using twice as much filter area as the minimum. Doubling the filter area will cut filter resistance by a factor of four, double the time required between filter cleanings, and make our filters last four times as long. That comes out to 500 to 600 square feet of filter area for my cyclone. Most small shop dust collectors have less than 120 square feet of area and really need over 600 square feet at typical dust collector dust loading. This means dust collectors need four times as much area and other cyclones far more as well. For what it is worth, this is why so many end up very unhappy with their dust collector cartridges needing constant cleaning.
Filter Type - A pair of the big Farr or Farr compatible 270 to 300 square foot blended poly paper fiber filters work great on my cyclone design, but the all poly filters that cost more than twice as much are a better buy. The all poly spun bond filters provide the same level of filtering with half as much surface area, so we only need half the total filter area. Unlike paper poly blended filters that get tossed when their filtering gets bad, we simply wash the poly filters to restore their full filtering ability. We can wash the all poly filters three to five times before they need replaced. The all poly filters are also more forgiving than the light blended filter material during cleaning.
Filter Sources - I bought my original fine filters from Donaldson Torit directly, but they that firm was not well setup to deal with hobbyists and small orders. There were payment issues and shipping damage. I now buy my filters from Wynn Environmental (http://www.wynnenv.com/cartridge_filters.htm). Wynn Environmental is a family run business that between Rick and Dick know more about filters than I know about cyclones. Most purchase a pair of their 9L300BL filters, but if you can afford the extra cost I prefer using a pair of their all spun bond polyester filters, model number 28B140SBOL.
Filter cleanout - Most of us make little cleanout boxes or drums below the filter tree from either a wooden box or from galvanized metal. Wynn has an exploded picture of a box arrangement. Shape is not that important, but a good seal is. I made mine out of galvanized steel with a wooden donut in the top and bottom with a 4” outlet on the side. I have an airtight cap to cover on that 4” outlet. To clean the filters I remove the cap, connect a long 4” hose going outside, turn on the cyclone and tap the filters a bit. Instead of tapping you can either blow on the outside of your filters with your vacuum set on blow or blow down with a compressor hose with the pressure set to 40 PSI or below. Clear Vue Cyclones come with some detailed instructions to build and setup your filter cleanup box (http://www.clearvuecyclones.com/ClearVue%20Installation%20Instructions%202007.pdf) .

Cyclone – To minimize our filtering overhead we need a good fine dust separating cyclone that both moves enough air to collect the fine dust as it is made and provides a very light dust loading on our filters. Don’t get fooled by vendors that provide filters that are wide open and freely pass the finest unhealthiest dust then say they provide a good fine dust separating cyclone because you rarely need to empty filters. I recommend either building my cyclone design from my web pages or buying the same 18” cyclone design from Clear Vue Cyclones (http://www.ClearVueCyclone.com)with the 5 hp motor and 15” impeller. This will also let you use 6” instead of 7” diameter ducting.

Tim Marks

01-04-2008, 5:37 PM

Makeup Air - If you blow outside I suggest at least a 14” diameter or larger air hole or open door/window for makeup air without whistling or chance of sucking carbon monoxide backward from your vents and flues into your shop
Actually very important to avoid damaging your house. People with "Whole House Fans" sometimes run into problems with this. Unless you open a door or a window for makeup air, you can end up sucking air laden with moisture in through cracks in the siding, leading to mold damage inside your walls.

Will Blick

01-04-2008, 7:13 PM

This thread keeps getting better. Bill P, fabulous check list you offered above..... Bill J, keep it coming, many of us are very interesting in learning as much as we can. A few questions I still have....

Bill J mentioned the airborne nature of micron, or sub micron size particles, makes perfect sense they are effected more by air current vs. gravity. Would this suggest a fine water misting system, such as ultrasonic, that delivers ultra fine mist as being beneficial, as it would possibly drop the fine dust out of the air? Just curious, in the desert, the added moisture is nice anyway.... I am not talking about tons of moisture that would effect the wood itself.

When we wear our 3m 7500 respirator with dust cartridges, I believe the cartridges filter down to .3 micron, IIRC. (does anyone know the right value here?) Is there any studies that show how small the wood dust actually is? Is a lot of the wood dust smaller than .3 micron? Maybe just a very tiny % is under .3 micron? I would consider this very critical information when understanding how effective these masks are. Of course, I am only referring to the dust which remains after a cyclone collects the big dust / chips and exhausts the remains out of the building.

Will Blick

01-04-2008, 8:53 PM

A final question:

Woods that are classified as sensitizers.... do they eventually make you allergic to that species of wood, or ALL species of wood? I was never clear on this issue. So i assume, if you have no known wood allergies, it might be prudent to avoid woods classified as sensitizers? Or at least reduce the use of them?

Also, many of us have expressed a strong interest to buy buy Bill P's book on dust collection. After reading his web page, and the expenses he has occurred already sharing this information, buying equipment, etc. ..... Till such a book is every published, (which to my knowledge he has never committed to writing one), Bill accepts PayPal contributions at BPentz@cnets.net.

From Bill P's web site....

Helping the thousands who view these pages daily leaves a positive feeling, but does not pay the bills. Since 1999 when I began sharing this work I have spent at least $10,000 every year on these dust collection education efforts. In 2006 my actual expenses on ISP access, licensing, testing, test equipment, and refining the designs I share cost me $15,892.05 out of pocket. With only 14 donations in 2005 and 43 donations generating $492 in 2006 these donations plus a total of $3093.67 from advertisers for 2006 leaves this site not even coming close to covering its cost of operation. I admit this is a labor of love and my choice to keep this work going, but please, if you find this information useful support these efforts with a check for what you feel this information is worth or at least a small on-line contribution each time you visit these pages.

Jim Becker

01-04-2008, 9:08 PM

Woods that are classified as sensitizers.... do they eventually make you allergic to that species of wood, or ALL species of wood?

For some folks the answer is yes. My locksmith is a good example. He used to be a carver...a lot of walnut 'cause there is a lot of it in this area. He got sensitized to it and after a bit, could no longer handle wood of any kind. He has to wear a mask and gloves just to drill a wood door...

The only really bad reaction I've had was to bubinga...and I'll not likely work with it ever again. Even with personal protection, it made me feel sick.

Will Blick

01-04-2008, 11:59 PM

OK, I found the data on the 3m dust cartridges
The filter is tested at 99.97% of airborne particles 0.3 micrometers (Âµm) in diameter.

This is pretty impressive IMO...

Jim, I remember you describing this earlier in the thread, I sure hope your locksmith was a rare exception, because many of the woods we use are classified as "sensitizers" Arggggg..... hopefully Bill P will ring in on this....

Doug Hobkirk

01-05-2008, 5:50 PM

I am very, very impressed that you are willing to spend the time and effort to write such detailed responses as you've written here. This last entry was a superb distillation of your research and expertise. I second the suggestion you write a book. I also second your suggestion / promise that you update (or have someone do it for you) your web site.

Furthermore, I think SMC should somehow scoop your most cogent posts and put them into a special category - maybe as a Stickey message in a new DC forum.

When do you break ground on the Bill Pentz Dust Collection Research Center?

But seriously, thank you sincerely from almost all of us for doing and sharing your research.

Dexter Hahn

01-07-2008, 2:31 PM

Dexter,

I've seen far too much to be a fan of Oneida Air Systems, so decline to comment.

Bill

I guess I don’t understand the above comment.

I’ve read your website on and off over the past few years, and you always seemed to highly recommend Oneida, which is why I asked you about that particular machine. One of my friends bought a 3hp Oneida system based on your recommendation. :confused:

Bill Jepson

01-07-2008, 3:10 PM

This is a response to Will's question above. The idea of a water mist system isn't bad, but you would have to mist the area and then enter later after the ambient level is lessened. For protection DURING WW it is hard to beat a dust collector. Production paint shops use a water curtain dust scrubber. The scrubber works just like the name implies, the spray booth is backed on one side by a curtain of deionized water. The difference is that the spray gun is positively charged and the piece being sprayed negitively charged. This draws the micro particles to the workpiece. The water curtain is also negitively charged. These systems control the environment much like a DC would. Not really practical for the hobbiest since the cheapest I've seen started around 18-20K dollars. There have been ion particulate sustems for actual clean rooms but again they are super expensive. They are only really effective when the air is very clean to begin with anyway. Wood dust isn't even close. A good dust collector is the most cost effective way to protect yourself I'm pretty sure.
Bill J

Will Blick

01-07-2008, 3:34 PM

Bill Jepson

01-07-2008, 5:45 PM

Bill J, thanks for the response....by no means was I suggesting an ultra sonic mister in lieu of a dust collector, I was only suggesting it as an added line of protection. For example, when hand sanding, a ultrasonic mister in the area above where you stand would drop the fine particles out of the air. Of course, if you can wear a respirator, it would be more desirable, but sometimes i have a hard time wearing them for an entire day....

Will,
Two things; First, one of the big troubles with water in our woodshops is the number of iron tool surfaces. Big rust problems can occur on them.
Second, Are you any relation to the art equipment suppliers, Richard Blick?
Lastly even if you are not, considering the usual nickname Richard's parents were cruel.:D
Bill J

Dave MacArthur

01-07-2008, 6:26 PM

.... When someone specifically says they decline to comment on a public forum, why would you attempt to force them to comment? I truly enjoy reading posts from Mr. Pentz, but end up disappointed with the threads inevitably.

Mr. Pentz, thanks much for the outstanding efforts and this great synopsis up above--it's probably the most understandable run-down I've read. I appreciate your time, and even more your willingness to stand up and be a target while helping others, despite knowing there are snipers all over the woods... Very brave, my respects.

Tim Marks

01-07-2008, 7:20 PM

I guess I don’t understand the above comment (about Oneida)
Try reading the "controversy" article on Bill's website, and connecting the dots (since he doesn't come right out and name them... BTW, Oneida has a patent on a dust-less floor sanding system):

http://billpentz.com/woodworking/cyclone/Index.cfm#Controversy

Will Blick

01-07-2008, 8:47 PM

Bill J, no relations to the Dick Blick art store chain! I wish there was!

I understand about the rust issue.... the misters I refer to are small area misters, only for specific area use, (certainly not over your TS) but, I understand they can cause some oxidation problems.

I find it interesting here in the SW desert, I blast my shop with a huge swamp cooler all summer, 24/7. It drops my ambient temp down 30 - 35 during the hot months. Yet, I never once had the iron rust on any tools.... I guess this is factor of just how low the humidity is, before the air goes through the swamper. Other parts of the country could never get away with this... I think the swamp cooler itself is of great help, as you are constantly changing out the shop air, as well as saturating it.

As for Bill P, he can not log onto this web site, so he won't read the appreciative posts offered above. I suggest you email him direct. And thanks to the poster who suggested where the problem arose from.... I too am disturbed by this.... not so much for Bill P, as he probably gets tired writing the same things over and over, wasting countless hours helping everyone for free.

But rather, to have someone with his knowledge and generosity cut-off like this makes one wonder. Kieth mentioned in another thread, it may only last a few days as they are investigating a TOS issue, and that thread was closed.

What makes forums great is having enough experienced people in certain areas to balance out the questions in those areas. It also creates viable and search-able content for many years to come. Bill P was about the best I have ever seen in this regard, specially considering his area of expertise revolves around safety.

If I owned a forum like this, I would beg him to participate...and if there was some violation of the TOS, I would work hard to correct such before any action was taken. Just one mans opinion.

On Woodnet, I feel one particular person, Howard Acheson, almost single handedly built that forum to probably the largest ww forum today. Howard does participate here, but not as often, but I sure wish he frequent us more often. He was, and still is one of the most knowledge contributors to any hobbiest type ww forum I have seen. I think forum owners should start appreciating the value of these type of contributors, as without these type of super stars, the forums have a bit less appeal.

Ken Fitzgerald

01-07-2008, 9:07 PM

Believe me Will......Keith does appreciate the advice given by the "Superstars" but even the "Superstars" must function within the boundaries of the TOSs.

That's one of the things that I've enjoyed so much about the Creek. Pros and beginners alike exchanging information in a civil manner. It's also why the Creek has grown so much in the past few years.

John Browne

01-08-2008, 12:38 AM

Oooh. That is a good question that I have wondered about myself. Can't imagine why it wouldn't work.

The air--I believe--has very little thermal mass. You can replace all the air and not significantly lower the temperature because of all the thermal mass in your shop from machinery, walls, cabinets, etc.

John Browne

01-08-2008, 12:47 AM

Couple of questions for Bill...

I've read his web site--ok, not the entire thing, but most of the stuff about airborne particulates and fine dust threats etc. And I bought the book on dust control and read it as well. Sounds scary and I plan to put my DC outside my shop and keep the stuff away from my lungs.

BUT...

the problem I have with all this is that 1) lots and lots of people do woodworking--have done woodworking in the past--without a fraction of the dust control he advocates with no noticeable health problems. I would bet a survey/study would show that a minority of WWers have respiratory problems related to dust inhalation. 2) a client is a large boat yard which in their last OSHA inspection was told by the inspector that it was the best inspection he'd done in 20 years. As far as I can tell they have no dust collection on their many WW tools at all (3 PM 66 table saws, several Delta band saws, sanders, etc). The principals of this shop have built wooden boats, or worked on wood around boats, for decades. Recently they had one person develop an allergic reaction not to wood but to fiberglass resin.

So my question is, if it's so dangerous, and so hard to get the fine particles out of the air, how come most people don't get sick from woodworking? And, if most people don't get sick, how can we say it's so dangerous?

Please understand, this isn't Bill Pentz bashing--I think the guy has done a noble service to compile all this information with little if any compensation for his troubles. And I'm not interested in cyclone design debates. I'm just trying to get to the facts to accurately assess the degree of risk I'm taking.

Thanks,

John

Will Blick

01-08-2008, 1:00 AM

John, Bill P is locked out of SMC till further notice, I certainly hope he returns.... a few comments on your post...

I agree with your methodology of trying to determine just how damaging the fine wood dust is (or even the large wood dust) by looking back at history. I too think it holds some of the answers to just how risky wood dust is. Like mentioned prior in this thread, there seems to be some analogies to smoking cigarettes here, i.e. some can smoke and die of lung cancer at 40, while others smoke till they are in their 90's and die from something else.

Grain workers have suffered a lot of respiratory healthy problems due to fine dust. I suspect their industry has better clearing house of these types of problems, and therefore their fine dust gets more media exposure.

I too was trying to find more answers regarding what % of long term woodworkers have dust related illnesses. The data seems a bit elusive, hence why i was probing Bill P for his comments on this subject, because in the absence of hard data, sometimes we have to rely on the closest thing we can find - such as a clearing house of data, and it maybe, that might be Bill P is the closest thing we have to a clearing house.

Hopefully when Bill P returns to this thread, he will provide a bit more data in this area.

Ken Fitzgerald

01-08-2008, 1:27 AM

I don't think you have to be a rocket scientist to realize that long term exposure to any foreign matter that can be inhaled will have some effects on one's lungs. The rate of the effect or the severity will depend on each individual, their physical conditioning, their genetics and the state of their lungs and the particulant matter inhaled, the length of the exposure and the concentration of the exposure. If something can be breathed in sufficient quantitites it will eventually have an effect. Whether the effects are acute or chronic will depend the type of matter, the concentration of the matter and the length of exposure and each person's individual physical characteristics.

I would suspect that the type of wood dust inhaled will have a great effect too. If you are breathing "treated" wood dust versus the same dust of untreated wood for example.

I think there are a lot of unknown, unproven, undocumented theories. I don't have a lot of trust of "studies". In today's world too many people rush studies to get the admiration of their collegues and the general public. Everyday new studies are released reversing or contradicting another study that was also a recent release. I also want to know who funded directly or indirectly a given study. I also want to know what the pre-study personal opinion of the person or group performing the study. Often I wonder if it's not easier to prove a preconceived theory than to perform a unbiased study for a scientic result.

I come from a long line of hillbillies. My paternal grandmother smoked a pipe and cigarettes until the day she died. She died at age 89. My two oldest children still refer to her as "Great-grandma who smoked a pipe"...I had to quit smoking cigarettes at age 56........that was 40 lbs. ago......

JMHO......

Dave MacArthur

01-08-2008, 1:55 AM

John, there is a post earlier in the thread which I think anwsers your post well,
http://www.sawmillcreek.org/showpost.php?p=541134&postcount=37

One problem with any discussion on dangers of any substance on humans is that people want to be able to treat "woodworkers" as an exact replicable quantity; that is, we want an answer similar to "at dust levels of WALNUT of 200 ppm, a woodworker will begin suffering mild alergic reactions, at 400 ppm it will grow chronic.." Now, of course when you read it like that, you remember we're all different and folks react differently, but it seems the instant people begin citing examples of 4 boat builders who have never had any problems, they've completely forgotten this truth.

No citation of individual cases of HEALTH is really a valid argument in this discussion. The only valid methodology is the same one followed by the FDA for drug testing--collecting statistically significant numbers of examples, study the rare cases where someone has a bad reaction to the test material, attempting to correlate problems with wood dust as a causal agent by ruling out questionable causal examples. Then correlating results to give some probability distributions on first how many people will have negative reactions to wood dust at various levels, and of those people, a probability of how severe the reaction will be.

Saying that a minority of woodworkers have problems, therefore it can't be that dangerous, is the EXACT SAME logical argument as this:
"Most people driving their car today will not die, or even suffer any injury. Therefore it must not be that dangerous. Therefore, discussion and efforts to make it more safe, and further reduce an already very small accident rate, must be a misguided waste of time and money".
It's a valid philosophical stance ONLY if you always happen to be in the car that arrives home safely. For the 500 people that die tonight on the road, it's errors are easily perceived.
We each must ask ourselves how much we'd like to depend on having the best genetics possible for tolerating wood dust, versus how much we'd like to guard against being "the guy hit by a mack truck on the way home". For many, it is worth the cost to take risk management measures--perhaps totally un-necessary for me, but maybe needed for my brother, no one knows ahead of time.

John Stevens

01-08-2008, 7:42 AM

John, there is a post earlier in the thread which I think anwsers your post well...

Hi, Dave. I think you misunderstand my point: the OSHA standard isn't a good one for gauging risk.

I'm not an oncologist or a statistician. My educational background is history and law, which is equally as important as science when it comes to understanding how executive agencies like OSHA set their standards for things like exposure to wood dust. Although these standards are based upon the testimony of scientists, there are varying degrees of political influence that bear upon which scientists testify and whose testimony is believed. The political influences can cause a standard to be based on testimony that is not the most scientifically accurate. The OSHA standard given by Bill Pentz is a good example of this, as common experience shows.

In the case of the OSHA standard, Bill Pentz quoted an inspector who told him that the amount of fine dust dissipated inside a two-car garage after hand sawing a seven-inch cut in a piece of wood 3/4" thick would be above the allowable standard. Now we all know how little dust that is. Anyone who rides in a car and sits in a line of traffic waiting for a light to turn is exposed to that much fine dust on a continuing basis. Anyone who sweeps their home is exposed to that much fine dust. I could go on, but I trust you get the point: nobody seems to worry too much about these other sources of fine dust, and the usefulness of the activity is so obvious and the risk so negligible that we're not even conscious of the risk-benefit tradeoff.

No offense intended, but I think you missed one of the points of Dr. Pan's post: we can't live risk-free, and that we should be reasonable about reducing risk in order to achieve benefits. Common experience shows that the OSHA standard cited by Bill Pentz is not a reasonable standard for gauging risk in regard to health problems caused by exposure to fine wood dust.

Regards,

John

Will Blick

01-08-2008, 9:48 AM

Ken, your points are very valid.... and it seems you have some fabulous genes :-)

Dave, thanks for that link, its the first "semi" scientific study, or at least abstracts I have seen.

John, you wrote:

>we can't live risk-free, and that we should be reasonable about reducing risk in order to achieve benefits.

John, this is what it all boils down to.... I am sure I am stating the obvious here.... for me, its not a question of risk-free ww.... but rather, how do I perceive these risks, and how much inconvenience am I will to live with in the shop, respirators, DC, not tracking dusty clothes into the house, cleaning shop on a regular basis, constantly exhausting air, etc. etc.

I am sure many of us have the same approach... the level of risk we perceive often dictates the level of response. The other real value of these threads is knowledge of the symptoms. As with many health problems, its often difficult to find the culprit... prior to Bill P's web site, I would have never suspected wood dust being the culprit of skin irritations or even mild nasal allergies, since I have suffered them on/off most of my life. I have already experienced some nasal responses to those dusty days. Of course, I often just thought there was some high levels of pollen in the air, as my allergic responses were often delayed, which adds to the confusion.

Unlike cigarettes, where they are relatively similar (of course they vary also in the tobacco used, filter, additives, etc. etc.), the biggest variable is cigs smoked per day, and for how many years. And of course, there is some good historical data in this field. But with ww dust, we have MUCH less data, and IMO, a real "wild card" - wood types.

Obviously MDF is needs to be treated with respect as it has many toxic chemicals. But it's these sensitizer woods that really have me worried. I fear working with a sensitizer wood (which their is MANY, and not all species are known whether they are sensitizers), which leads to the start of health problems, which then makes me sensitive to all wood dust, like Jims locksmith. Then, for me, I will be finished ww. I am trying to avoid this "judgement day." Due to internet data on this subject, (mainly Bill P and wonderful threads like this) I am armed with the basic premise of the risks, wood types, etc.... which I will use prudently.

So thanks to everyone that takes their time to share what knowledge they have in this area.

Hank Phillips

01-08-2008, 12:15 PM

[/color]
Try reading the "controversy" article on Bill's website, and connecting the dots (since he doesn't come right out and name them... BTW, Oneida has a patent on a dust-less floor sanding system):

http://billpentz.com/woodworking/cyclone/Index.cfm#Controversy

I also remember Bill P. singing Oneida's praises not too long ago. Oneida has some of the older Pentz web pages on their site as well as an email dialog between bill and Oneida.
http://www.oneida-air.com/newsite/comments.php

Ken Fitzgerald

01-08-2008, 12:33 PM

Folks.....this thread is very closely being watched. We won't allow it to degrade to a discussion on Bill P, Onieda or any other company and their entertwined relationships...fallouts.....who did what to whom.....etc. Any further drifting in that direction and I will close and move the thread.

Wilbur Pan

01-08-2008, 4:01 PM

In the case of the OSHA standard, Bill Pentz quoted an inspector who told him that the amount of fine dust dissipated inside a two-car garage after hand sawing a seven-inch cut in a piece of wood 3/4" thick would be above the allowable standard.

This may seem silly at first glance, but let's do some math.

The OSHA level for hardwood exposure is 1 mg/m3. The density of hardwoods is in the 35-45 lbs/ft3 range. Let's use 40 lbs/ft3 as a middle of the road number. A 20'x20' shop with 8' ceilings has a volume of 3200 cubic feet, or 90 cubic meters. That means that once you hit 90 mg of wood dust, you've hit OSHA levels.

90 mg of wood dust is 0.0002 pounds. At 40 lbs/ft3, that's 0.000005 cubic feet of wood, or 0.0086 cubic inches. A Lie-Nielsen dovetail saw has a kerf of 0.026 inches. If you use an LN dovetail saw to cut 3/4" thick wood, a 1/2" long cut in a 3/4" board with a kerf 0.026" wide gives you 0.0086 cubic inches of wood dust, if the conversion of the wood in the saw kerf to dust is 100% efficient. Now, some of that wood in the kerf won't be converted to dust, but may be sawn into shavings. Suppose only 5% of the wood cut by a handsaw gets cut up into dust. That's a 10" long cut that generates enough dust to hit OSHA levels. So the OSHA guy may not be completely off base.

No offense intended, but I think you missed one of the points of Dr. Pan's post: we can't live risk-free, and that we should be reasonable about reducing risk in order to achieve benefits. Common experience shows that the OSHA standard cited by Bill Pentz is not a reasonable standard for gauging risk in regard to health problems caused by exposure to fine wood dust.

Since you're referencing my post, I'd like to make one thing clear. I don't think that OSHA standards are reasonable. I think they are too lax in regard to health problems. The Europeans have a much better handle on worker safety issues than we do in the US, and they have stricter standards. There is a lot of evidence to show that increasing wood dust exposure leads to an increased incidence of lung disease (http://sawmillcreek.org/showthread.php?p=454754#post454754).

Now, as you rightly point out, you can't live risk free, and this does not stop me from building a woodworking shop in my basement. But this does not mean that the OSHA standard has no basis, even though I think it should be stricter.

By the way, the fine dust generated by wood has a particular irritating effect on the small airways of the lungs that the fine dust from car exhaust and house dust do not, primarily due to the structure of the cell walls of the tree and the subsequent difficulty of the lung's mechanisms to clear wood dust particles. About the only things I can think of that is similarly irritating to the lungs are the fine particles generated from cigarette smoke and asbestos.

For the record, when I'm generating dust, I have a dust collector with a very short hose run that I move from machine to machine, I have a 1 micron air cleaner that is sized to circulate the air in my shop about 25 times an hour, and I wear a mask with a P100 filter.

Dave MacArthur

01-09-2008, 3:14 AM

very interesting responses, which I've enjoyed thinking about.

John Stevens

01-09-2008, 6:57 AM

There is a lot of evidence to show that increasing wood dust exposure leads to an increased incidence of lung disease (http://sawmillcreek.org/showthread.php?p=454754#post454754).

Dr. Pan, as you probably realize, this statement is only meaningful if we know (at a minimum) what the baseline risk is and what the risk is after exposure at the 1mg/m^3 level for a specified period of time. Can you give us some numbers here?

EDIT: It would also be useful to define the term "lung disease" and disaggregate it, since most people are probably worried about COPD and cancer rather than illnesses that will clear up after a short time without any treatment other than avoiding exposure to wood dust.

Thanks in advance.

Regards,

John

Wilbur Pan

01-09-2008, 11:29 PM

By lung disease I do mean COPD and cancer. Those are the diseases that are looked at in the studies I cited.

Here (http://www.sawmillcreek.org/showthread.php?p=454805#post454805) is a post I made regarding how to interpret this data. In a nutshell, people want to know, "If I spend 4 hours in my workshop each weekend, what are my chances of developing COPD?" From a medical perspective, this is not a useful number, or a number that is possible to give to an individual. This assumes that all people are equal and that the only issue is how much dust you are exposed to. This is certainly not the case. The chances for developing COPD from wood dust exposure is different for a woodworker who smokes, a woodworker who does not some, a woodworker with a family history of asthma, and so on.

The other issue is that the health risks from dust exposure follow a dose response curve, so that issues of lung function start to occur as soon as the wood dust exposure happens. That's why the issue of a "safe" level doesn't really exist. But in the interest of conserving electrons, please read my original post.

As far as acute vs. chronic effects on lung function from wood dust is concerned, you can read why you can't separate the two here (http://sawmillcreek.org/showthread.php?p=454864#post454864).

Rick Schubert

01-09-2008, 11:43 PM

[quote=Will Blick;736611]OK, I found the data on the 3m dust cartridges
The filter is tested at 99.97% of airborne particles 0.3 micrometers (Âµm) in diameter.

This is pretty impressive IMO...

Will,

Which model of 3M filter cartridge is this?

Thanks, Rick

John Stevens

01-10-2008, 7:07 AM

In a nutshell, people want to know, "If I spend 4 hours in my workshop each weekend, what are my chances of developing COPD?" From a medical perspective, this is not a useful number, or a number that is possible to give to an individual.

I acknowledge that from a medical perspective, this is not a useful number. However, the issue I raise (whether the OSHA standard is a useful one for gauging risk in woodworkers) is not a purely medical one. There's a whole body of thought in law and economics that deals with problems such as this. Although it's not possible to determine individual risk, government safety standards such as the OSHA standard in question, are supposed to be the result of a balance of aggregate risk (injuries/illnesses per x number of man-hours), the costs of those risks, and the costs of preventing the illnesses and injuries, against the benefits of the activities that cause them. Your earlier posts (to which you linked) are informative as to the health risks of woodworking, but they're not dispositive as to the utility of the OSHA standard for gauging risk for woodworkers.

I usually avoid reading and participating in these threads about wood dust because they uniformly generate more heat than light. This one is no exception, so with that I'll just thank you for the conversation (sincerely, no sarcasm here) and say so long for now.

Cordially,

John

Phil Thien

01-10-2008, 8:41 AM

However, the issue I raise (whether the OSHA standard is a useful one for gauging risk in woodworkers) is not a purely medical one. There's a whole body of thought in law and economics that deals with problems such as this.

My original response: Yeah, but the last time I checked my pulmonologist was a doctor, not a lawyer. :p

My updated response: I'm not sure what you were driving at, and perhaps I shouldn't have been too dismissive. If you do return, I would like to hear more about this angle.

However, I do feel that ultimately, working in a small home shop (and having nobody to blame but myself for my lack of diligence in controlling the dust), that I should take Dr. Pan's linked studies very seriously. The way it comes down is this: Workers in commercial shops that have better dust controls than I have suffered from the exposure to woodworking dust. I cannot imagine I am somehow immuned because I only work a few hours here and there.

But again, perhaps I am missing your point about the OSHA standards and if you do return to this thread, I'm all ears.

Art Hackman

01-23-2009, 9:32 AM

As a new member & this being my first post, I apprecialte Bill Pentz & his thankless (for the most part) effort. After reading almost all of his web site info several years ago, and as a registered engineer licensed in the state of Missouri (retired), I could only agree with him. The first major expense in building my first real wood working shop was the purchase of a Clear Vue.
Thank you again Bill for all your effort.
Respectfully,
Art