Bill Pentz and Cyclone Test

[Phil Thien]

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.

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

[Don Baer]

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]

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]

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]

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. 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]

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]

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. 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]

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]

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]

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]

Ben,

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

Jay

[Steve knight]

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.

[Abe Low]

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]

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]

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