Bill Pentz and Cyclone Test

[Will Blick]

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]

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]

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]

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]

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 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...TableSmAAF.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 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 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]

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]

...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]

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]

Yawn! Here we go again.

[Hank Phillips]

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/cyc...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]

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]

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]

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]

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) 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 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]

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