Phil Thien's Baffle and Bill Pentz

[Duane Meadows]

We'll see what else my wife can turn up when she actually has some free time at her lab to look for more papers. For me, the biggest change in my thoughts on DC from finding 3 additional papers is changing my mind about what to do with the "waste" air. I was firmly in the "it's too expensive to dump it outside so I have to filter it" camp. Now, given the data vs the commercially available filters, I've been converted to the idea of dumping the waste air outside and paying whatever it costs to keep the temp and humidity in the shop under control.

One thing that rather amuses me... if fine wood dust is a major health hazard(and it may well be), why is one of the first respones to blow it outdoors and make it your neighbors problem as well? Share the misery? And spend a lot of money on HVAC to do it?

As for allergies, they can change over time. I have had periods in my life when I,ve had extreme poison ivy reactions. Have also had times when I could pull it up by the handful and get no reaction. My wife has in recent years developed a rather severe allergy to wheat products. Our bodies change. Our diet changes. Many things, I think, can affect how our bodies handle irritants over our lives.

I tend to agree with Phil. Dust may become an issue for a small percentage of woodworkers. Wheat is becoming an issue for a ever increasing percentage of people. Is it a good idea to minimize the amount of dust we breath? Surely it is! Is it something we chase to the last dust particle? For the vast majority of woodworkers, I think not! For the majority of us, there are much greater health risks.

As Phil said, the biggest advantage to me, is spending less time cleaning up. Also keep in mind that as with ANY "scientific" study, one must be a little sceptical of who paid for the study, and who benefits most from the results! I rarely take them at face value.

[Art Mann]

If the standards recommended by Bill Pentz and apparently Mr. Williams are taken seriously, then woodworking is only an activity for the well equipped professional or the very rich. Implementing a system that achieves those standards would cost more than the entire equipment investment on a majority of small hobby shops. Should we just tell those poor suckers who can only afford a $600 contractor's saw with poor dust collection that they are killing themselves if they continue to use it. There is simply no evidence that is true. Studies of full time employees in industrial environments simply aren't directly applicable. I think that is doing as much of a disservice to the hobby woodworking community as telling them to just ignore wood dust altogether.

[Chris Parks]

Phil, at what level of activity does a person move from needing little or no protection to needing a more efficient system?

How many hours a week defines a hobbyist and how did you arrive at that figure?

Would you please list the companies who are ripping people off so they can be avoided, not as a general answer but company names.

[Jim Neeley]

Here is some food for thought. Lima beans contain a measurable amount of potassium cyanide. If it weren't already a widely distributed food crop, the FDA would never approve it for human consumption. Should we stop eating lime beans?

*NOW* I know why I don't eat lima's!!

[Phil Thien]

Phil, at what level of activity does a person move from needing little or no protection to needing a more efficient system?

How many hours a week defines a hobbyist and how did you arrive at that figure?

Would you please list the companies who are ripping people off so they can be avoided, not as a general answer but company names.

Chris, please point out where I said people need little or no protection.

As far as what constitutes hobby vs. pro vs. industrial use, I think we can leave that to the individual, let them apply common sense.

In terms of naming companies that are ripping people off, my goal is to help people identify scare tactics. There is really no need to name names, educated consumers will know it when they see it.

[Ty Williams]

Does that sound like your shop? Eight hours a day, day-in and day-out, processing lumber, using old machines with no real means of exhausting the dust?

Yes, actually, I think that, other than the duration, that sounds like a LOT of hobbyist woodworking shops. How often do people on this very forum get told to "buy old iron"? And I'm also not convinced that there's not a lot of hobbyist shops that in reality have far more hours of exposure than you acknowledge. Think about how many guys have their shop in a basement or attached garage. Either of those shares airspace, intentionally or not, with the house. So you've got a guy who either has no DC because a fair amount of SMC doesn't think it's that important, or has a Shop Vac, or even a Harbor Freight DC with a 30 micron bag and then he as probably 2-3 ACH between his shop area and his living area. His exposure doesn't end when he walks through the cheap, poorly sealed door between the house and the garage. He's effectively unprotected in both the shop and the house, opening the possibility of spending much more than 8 hours a day exposed to problematic levels of dust.

That reads like the plywood, three cabinet, and four furniture facilities did not contribute any significant respiratory effects. Sawmill and milling center sure, but making comparisons between our shops (which we use 1-4 hours here and there) and a sawmill where you'd be working 40+ hours/week for years on end, well, it is a bit like comparing apples to oranges

Three main objections to your objection to that quote, all of which were in my wife's initial summary of the papers:
1) They're using US thresholds for harm to the workers. The civilized world, unlike the US, doesn't allow people to get that sick on the job and yet call the worker healthy. Just how much are you willing to reduce someone's lung capacity before you agree that harm has been done?
2) Dead, disabled, and scared off workers aren't counted in the samples. If management forced the guy out because he was making too many doctor's visits on the company's dime (via workman's comp), that data point never shows in the study. If you don't believe that happens, well, you've never worked in an Employment At Will state.
3) The paper splits out dust comprised solely of cellulosic materials from dust that is unavoidable in wood processing but isn't cellulosic. This allows them to say that "wood solids" aren't what's hurting you. Again, my lungs can't sort out the one from the other. If one harms people and I get both kinds no matter what, it's a false distinction.

One thing that rather amuses me... if fine wood dust is a major health hazard(and it may well be), why is one of the first respones to blow it outdoors and make it your neighbors problem as well? Share the misery? And spend a lot of money on HVAC to do it?

Dilution is the solution. Put it into the outside air and the PPM drops to the point it's not going to hurt anyone.

If the standards recommended by Bill Pentz and apparently Mr. Williams are taken seriously, then woodworking is only an activity for the well equipped professional or the very rich. Implementing a system that achieves those standards would cost more than the entire equipment investment on a majority of small hobby shops.

Actually, if you think that, you need to take a harder look at what Pentz recommends and what it takes, from an engineering perspective, to implement what the math requires. At a minimum, you really only need a blower that'll move 1000CFM through your ducting, about 6" diameter duct, and some way to hook that to your machine. That's not going to cost a fortune if you're willing to roll your own and spend some time looking through a catalog. I certainly can't afford a $2k dust collection system! I'm stretching to spend $600 on mine. It doesn't have to be as expensive as a lot of the naysayers make out. Granted, if you live in the city with close neighbors you're going to need something to trap the largest stuff in a bucket so you don't make a tan pile outside your shop, but that's what the Thein Baffle is for. If you think the only way to achieve what the math requires is to spend thousands, you're doing it wrong. The reason to spend thousands is to make it easier, faster, and closer to turn-key. If that doesn't seem worth the money, do it yourself for a fraction of that.

Should we just tell those poor suckers who can only afford a $600 contractor's saw with poor dust collection that they are killing themselves if they continue to use it.

Of course not! What they do need to hear is that the dust is dangerous and that danger shouldn't be ignored. So, $600 contractor's saw is all you can afford? OK, wheel it into the driveway to use it and wear a NIOSH certified N100 or P100 mask while you're using it, then vacuum it well before you bring it back inside. Or go to TSC and buy one of those big 48" fans and blow it in one door (with an open door on the other side of the shop) while you work and for a while afterwards (and still wear the P100 mask). There's a lot of ways to skin this cat, but the thing that we need to accept is that using a 30 micron bag or a 5 micron canister and thinking we're safe because we have a clean shop is just a serious mistake.

Studies of full time employees in industrial environments simply aren't directly applicable.

I agree but for a different reason than you, I bet. If you look at the numbers people are recording at home on their Dylos meters (and even other more sophisticated meters), they're generally over the MPEL for OSHA-regulated shops.

Would you please list the companies who are ripping people off so they can be avoided, not as a general answer but company names.

I am fairly sure he's accusing ClearVue of that. I have to admit, I've never seen any advertising for their products other than the logo at the beginning of Marc's videos, so I don't know how much they try to use scare tactics. I looked at their units recently when picking out my own DC. As far as I can tell, they're not doing anything special, they're just the best of the off-the-shelf, turn-key dust collection systems in terms of performance. You pay a big price premium for that, and I've certainly noticed a lot of people being resentful at having to pay more for something that does more. Really, all their product boils down to is a bigger blower than other companies are using and a cyclone with a different aspect ratio so that it separates somewhat smaller particles down into the bin rather than blowing them outside (or into the filter). I was interested in their products because I could simply pick up the phone and order something that moved enough air to do what the math says needs done. In the end, they simply charge too much for that convenience, I'd rather save the money and make it myself.

[Michael W. Clark]

You really need to be aiming for "High Efficiency" (ASME AG-1a–2004, “Addenda to ASME AG-1–2003 Code on Nuclear Air and Gas Treatment”, 2004) standards, which are better than 99.97% of particles 0.3 micron and larger, single pass efficiency. I'm not aware of any commercially available filters that reach this. The closest I'm aware of are the Wynn Environmental Nanofibre filters which are MERV15 (85%-95% of 0.3-1 micron particles, single pass).

99.97% @ 0.3 is the US definition of HEPA. They are commercially available, but $$. MERV ratings are a stretch to compare to HEPA, it's a different test and rating system.

Polyester felt (16 oz) is easily 99%+ @ 2.0 micron. Polyester with PTFE coating will typically get you 99%+ @ 0.5 micron. These are commonly available filter materials.

Not sure about the Wynn material, but the media on my Jet cartridge is a woven material, not felted. Filtering is done by the dust cake, not the media like with a felted fabric. Hard to say what the real efficiency is in this case.
Mike

[Duane Meadows]

Dilution is the solution. Put it into the outside air and the PPM drops to the point it's not going to hurt anyone.

.

If that is true, I think you just proved Phil's point!

[Phil Thien]

Yes, actually, I think that, other than the duration, that sounds like a LOT of hobbyist woodworking shops. How often do people on this very forum get told to "buy old iron"? And I'm also not convinced that there's not a lot of hobbyist shops that in reality have far more hours of exposure than you acknowledge. Think about how many guys have their shop in a basement or attached garage. Either of those shares airspace, intentionally or not, with the house. So you've got a guy who either has no DC because a fair amount of SMC doesn't think it's that important, or has a Shop Vac, or even a Harbor Freight DC with a 30 micron bag and then he as probably 2-3 ACH between his shop area and his living area. His exposure doesn't end when he walks through the cheap, poorly sealed door between the house and the garage. He's effectively unprotected in both the shop and the house, opening the possibility of spending much more than 8 hours a day exposed to problematic levels of dust.

You may BELIEVE that, but you cannot SUBSTANTIATE that.

What I've observed, from speaking with a great many woodworkers interested in practical solutions to controlling dust, is that those with 30-micon bags in a garage or basement quickly notice that the bags are insufficient.

Three main objections to your objection to that quote, all of which were in my wife's initial summary of the papers:
1) They're using US thresholds for harm to the workers. The civilized world, unlike the US, doesn't allow people to get that sick on the job and yet call the worker healthy. Just how much are you willing to reduce someone's lung capacity before you agree that harm has been done?
2) Dead, disabled, and scared off workers aren't counted in the samples. If management forced the guy out because he was making too many doctor's visits on the company's dime (via workman's comp), that data point never shows in the study. If you don't believe that happens, well, you've never worked in an Employment At Will state.
3) The paper splits out dust comprised solely of cellulosic materials from dust that is unavoidable in wood processing but isn't cellulosic. This allows them to say that "wood solids" aren't what's hurting you. Again, my lungs can't sort out the one from the other. If one harms people and I get both kinds no matter what, it's a false distinction.

Well you're the one that pointed to the studies as concerning enough that you announced you had changed course and were going to exhaust outside. I merely pointed out that one study was primarily sawmills with ZERO dust collection, and another study concluded that the dust wasn't harmful in eight out of ten locations they studied, and the problematic ones were a full-blown sawmill, and a milling center. People can re-read my post #105 above.

Now you say the Tulane study is worthless because they apparently stepped over the bodies of the dead to test the lungs of the living, and you point to the European standards.

Anyone thinking European standards evolved in a pure-science lobbying-free vacuum needs to read-up. You think lobbying/corruption is bad here (in the US)? You ain't seen nuttin'.

The U.S. standards are entirely sufficient.

Dilution is the solution. Put it into the outside air and the PPM drops to the point it's not going to hurt anyone.

As Duane points out below (or above, I guess), exposing ourselves to higher concentrations for shorter time periods and exposing ourselves to lower concentrations for longer time periods are both forms of dilution. In regards to wood dust, one may be safer than the other.

I agree but for a different reason than you, I bet. If you look at the numbers people are recording at home on their Dylos meters (and even other more sophisticated meters), they're generally over the MPEL for OSHA-regulated shops.

I wouldn't take that bet!

Lots of those with Dylos meters found a single-stage DC and an ambient air cleaner do a great job keeping their air clean. There are occasional spikes during machining, depending on devices used, but weighted averages are very low.

I am fairly sure he's accusing ClearVue of that.

Can you please point to where I've mentioned any companies by name?

Please refrain from speaking on my behalf, Ty.

[Jeff Duncan]

Just reading through here and figured I'd offer a couple points as food for thought....

One recurring thought is that woodworkers in small home shops cannot be compared to those in pro shops. In general I have to agree, but would offer a counterpoint. A woodworker in a large shop is in a large shop....usually measured in thousands of square feet with tall ceilings. A woodworker in a small home shop is confined to what....maybe several hundred square feet on average with low ceilings. Larger shops also implement far more extensive systems for capturing dust. Point being is that the dust in a small shop is likely to be far more concentrated in a smaller air space and may offset the reduced number of hours? A bad analogy may be like comparing sitting in the same restaurant as several people smoking, to sitting next to someone in a small office. Although there's far more smoke generated in the restaurant, the far greater area displaces it so your exposed to less of it than you would be in the office

Second point that's been discussed at length is the idea of venting dirty air to the outdoors. Again I agree with this on principle as being the best possible scenario. However it is not a realistic possibility in cold climates. I'll leave the math and formulas to the others. In my shop in the winter with a 10" fan discharging air to the outside the temperature drops quickly. Of course there are too many factors to put a specific and/or accurate degree drop over time, but just as an example it can easily drop 10 degrees over an hour. My heater running continuously does not prevent the drop. In fact it takes a LONG time to come back to temp once the fan is off. And although 10 degrees doesn't sound like much, it takes me from a temp safe for gluing and/or finishing, to one that is not

Third, as to the affects on health. I have no stance on this at all and I'm not taking sides. However keep in mind that the real boom in hobby woodworking shops is what.....50 years or so old tops? Probably half that if you want to talk about real quantities of people buying more than a small table saw and drill press. So in my opinion pointing to something so new and not seeing a long history of health affects is pretty much a moot point. Any data from industrial settings is going to be related, but not necessarily transferable. IMHO if you want good information wait about another 50 years or so and then see what's out there

Like I said, just a couple points to think about. I'm not taking sides and personally don't care much what others do in their shops. As I do this for a living my concerns are different and I have spent a LOT on dust collection and filtration, (more than many here have invested in their entire shops!), and frankly it's probably still not enough. But I do it b/c I need to do it for my particular situation. I'm not here to dictate what others do, but just figured I'd throw in a couple points to mull over for those keeping an open mind

JeffD

[Michael W. Clark]

Ty,"Dilution is the solution" is usually refering to indoor air quality. Some emissions are done based on mass/unit volume, but most are mass/unit time, especially for particulate. I know you are referring to residential, but thought it was relevent since the studies are industrial based.

As others have said, industrial planers and sawmills are quite different. "Old Arn" for home shops is still not going to compare these facilities. They usually exhaust tens of thousands of CFM and material disposal is measured in tons/hr.

[Ty Williams]

You may BELIEVE that, but you cannot SUBSTANTIATE that.

Particulates diffuse. This is well substantiated across many, many different disciplines. The average attached garage or basement is not well air-sealed away from the house. This is substantiated by the dozens of building science papers talking about the importance of improving garage and basement/crawlspace air-sealing standards in building code to improve the IAQ to avoid negative health impacts.

So if you disagree that wood dust gets into the house, are you denying that wood dust diffuses or denying that attached garages and basements exchange air with the interior of the house?

Now you say the Tulane study is worthless because they apparently stepped over the bodies of the dead to test the lungs of the living, and you point to the European standards.

I didn't accuse it of being worthless, I accused it of having set the bar too low. A "passing" outcome from using that standard isn't good enough. Research that still doesn't draw the line in the right place but at least gives you some place to start is still better than nothing.

Yes, I think European standards for worker safety are generally superior to those in the US because the US has swung faaaar too in favor of large corporations. Do I care if the EU regs swing just as far the other way? No, not at all because not hurting people is a lot more important than making money.

As Duane points out below (or above, I guess), exposing ourselves to higher concentrations for shorter time periods and exposing ourselves to lower concentrations for longer time periods are both forms of dilution. In regards to wood dust, one may be safer than the other.

Response to concentration isn't linear meaning you can't assume time averaging works the same as changing concentration. Some things have an exposure below which they're safe regardless of how long you're exposed to it. Increase the dose concentration past a certain point and it's damaging or fatal no matter how short of a time the exposure is. Most poisons, radiation, heck, even just oxygen works like that.

Can you please point to where I've mentioned any companies by name?

Please refrain from speaking on my behalf, Ty.

If you don't want the rest of us to have to speculate on what you mean, then you need to be specific.

So, lets put you on the spot now: What company or companies, specifically, were you talking about?

However keep in mind that the real boom in hobby woodworking shops is what.....50 years or so old tops? Probably half that if you want to talk about real quantities of people buying more than a small table saw and drill press. So in my opinion pointing to something so new and not seeing a long history of health affects is pretty much a moot point. Any data from industrial settings is going to be related, but not necessarily transferable. IMHO if you want good information wait about another 50 years or so and then see what's out there

This is something I wonder about every time I hear a comment along the lines of "well my grandfather/dad/uncle was a hobby woodworker and he lived to 95". I remember my grand dad's shop. The only power tools in it were a table saw and a drill press. My dad's shop, until recently, only added a planer and a router. A guy working away with a hand plane, table saw, some chisels, and hand sanding is going to have a much different exposure than a guy with a table saw, band saw, jointer, planer, drum sander, spindle sander, multiple routers, and power sanders. Think back to 1st season of New Yankee Workshop. What was an enviable TV dream shop then is pretty basic by today's standards. Norm had, what, a radial arm saw, table saw, lunchbox planer, his router, and some drills in the first couple of seasons. Oh, and a pneumatic brad nailer, can't forget that one! :lol: Now, look at Paul-Marcel's shop (keeping in the theme of woodworking videos I watch), which is just a hobbyist shop. He's got a big bandsaw, big table saw, big planer, multiple drum sanders, multiple routers, a pair of Dominos, jigsaws, a couple of scroll saws, etc. It's a whole different ball game than it was just 15 years ago.

I have to wonder if some of the reason we're arguing about this isn't that the anecdotal experiences that form people's intuitive risk assessment are from a time when the average guy didn't have all the power tools we have today.

[Phil Thien]

Particulates diffuse. This is well substantiated across many, many different disciplines. The average attached garage or basement is not well air-sealed away from the house. This is substantiated by the dozens of building science papers talking about the importance of improving garage and basement/crawlspace air-sealing standards in building code to improve the IAQ to avoid negative health impacts.

So if you disagree that wood dust gets into the house, are you denying that wood dust diffuses or denying that attached garages and basements exchange air with the interior of the house?

Well, you didn't quote my entire response. I said people in basement/garage shops don't typically use 30-micron bags for long. If they switch to a much finer bag, they are keeping the dust they capture. And if they have an ambient air cleaner, the air in their shop is cleaner than the air in the rest of their house.

But to answer your question (I bolded), garages never should have cold air returns, basements often don't (except in finished areas). My basement shop does not have a cold air return. So any diffusion which would occur in many houses would have to travel through open passage ways and gaps. Or if there is a cold air return, through a filter.

Your point seems to be that those even with good DC have to worry about dust escaping their shops via cracks under doors and other gaps, and exposing others in the house to what you consider harmful levels of dust.

I just think that is an irrational fear.

I didn't accuse it of being worthless, I accused it of having set the bar too low. A "passing" outcome from using that standard isn't good enough. Research that still doesn't draw the line in the right place but at least gives you some place to start is still better than nothing.

Yes, I think European standards for worker safety are generally superior to those in the US because the US has swung faaaar too in favor of large corporations. Do I care if the EU regs swing just as far the other way? No, not at all because not hurting people is a lot more important than making money.

Actually, lobbying for tighter standards often (typically?) come from corporations that want to mandate tighter standards to increase demand for their equipment and services.

Response to concentration isn't linear meaning you can't assume time averaging works the same as changing concentration. Some things have an exposure below which they're safe regardless of how long you're exposed to it. Increase the dose concentration past a certain point and it's damaging or fatal no matter how short of a time the exposure is. Most poisons, radiation, heck, even just oxygen works like that.

Right, I stated as much as that in my post. In can go both ways.

If you don't want the rest of us to have to speculate on what you mean, then you need to be specific.

So, lets put you on the spot now: What company or companies, specifically, were you talking about?

I'm not sure why you and Chris are obsessing over names. As I've said at least a couple of times now, I think it is more important to help people identify scare tactics than name names.

This is something I wonder about every time I hear a comment along the lines of "well my grandfather/dad/uncle was a hobby woodworker and he lived to 95". I remember my grand dad's shop. The only power tools in it were a table saw and a drill press. My dad's shop, until recently, only added a planer and a router. A guy working away with a hand plane, table saw, some chisels, and hand sanding is going to have a much different exposure than a guy with a table saw, band saw, jointer, planer, drum sander, spindle sander, multiple routers, and power sanders. Think back to 1st season of New Yankee Workshop. What was an enviable TV dream shop then is pretty basic by today's standards. Norm had, what, a radial arm saw, table saw, lunchbox planer, his router, and some drills in the first couple of seasons. Oh, and a pneumatic brad nailer, can't forget that one! :lol: Now, look at Paul-Marcel's shop (keeping in the theme of woodworking videos I watch), which is just a hobbyist shop. He's got a big bandsaw, big table saw, big planer, multiple drum sanders, multiple routers, a pair of Dominos, jigsaws, a couple of scroll saws, etc. It's a whole different ball game than it was just 15 years ago.

I have to wonder if some of the reason we're arguing about this isn't that the anecdotal experiences that form people's intuitive risk assessment are from a time when the average guy didn't have all the power tools we have today.

Those old shops with fewer tools often lacked a single important one: A dust collector. Even if some of them had DC (my grandfather's shop certainly didn't), then it probably had pretty poor bags. Those old timers were undoubtedly exposing themselves to quite a bit more dust than we are today, even with the additional tools at our disposal.

[Art Mann]

Now you guys are starting to make me feel really old. When I started woodworking in a serious way in the early '70s, I had a shop that included a table saw, a RAS, a jointer, a crude router table, a belt sander and lots of dust generating power hand tools. At that time, the hazards of wood dust were mostly unknown and dust collectors for the hobby woodworker were unheard of. I was only aware of the adverse effects of dust when I started coughing and my nose started running. Shops like mine were the norm. It is a mistake to assume shop dust in those days was any less risky than it is today. If the effects of dust inhalation were as dangerous as Bill Pentz represents them to be, then you would see statistically significant numbers of people like myself who are dying or becoming invalids from their hobby.

I am glad I have become aware of the hazards of dust inhalation and the methods to mitigate the risk. I am glad it is a topic of discussion on these forums. I just think there needs to be a little more sensibility applied to the issue. Here is a direct quote from Pentz's website, "... every exposure to fine dust causes a measurable loss of respiratory function, some of this loss becomes permanent ...". This is an example of the kind of wild exaggeration with which I take issue.