Should WW Forums have a position on dust hazards and practices?

[Gunnaduit]

New Wikipedia page
Health Hazards and Exposure Control of Wood Dust

Wikipedia talk:Articles for creation/Health hazards and exposure control of wood dust - Wikipedia, the free encyclopedia

At this stage, this is a draft article for creation submission within Wikipedia.

I have written it myself so far to get it afloat, and get it ready in time for it to be a main link for our WWF faq. As with all Wikipedia content, there is no single 'author', it is a community project. Everyone can be involved.

If anyone can add anything to it, then go for it. It definitely needs more content.

Please ensure that anything you write is properly referenced, as unfortunately unsubstantiated content will need to be deleted, especially if such content appears prior to acceptance.

Gunna

[nick_b00]

Gunna,

Reference 8 in you wiki list is now out of date. There's a 12th edition 2011.

Nick

[GraemeCook]

Nice initiative Groggy and Gunnaduit.

As always, the first step in harm minimisation is acknowledging that the risk exposure does exist, and that it is real.

Gunnaduit, as you develop the drafts for your Wiki have you considered publishing them here as a form of peer review ..... or in a parallel thread so as not to hijack Groggy's??

Fair Winds

Graeme

[mic-d]

I have a question, might seem to be from left field, but I have a reason. It'll be easier to ask the question first and hope to get an answer and then explain later. Is there air quality monitoring in High School workshops in Australia? Metering invisible dust in particular I mean.

[Gunnaduit]

Graeme, Yes I've spent a fair bit of time yesterday and today working up the Wikipedia article, ensuring that I've got almost everything referenced. Looking the stuff up on the web was easy, but distilling it down and doing all the very fiddly and pedantic citations certainly takes time.
But have a look -
Wikipedia talk:Articles for creation/Health hazards and exposure control of wood dust - Wikipedia, the free encyclopedia

Of course, being Wikipedia it can't cover practical build information, it's just the academic stuff. As far as a wiki for WWF here, I was wondering also if the Wiki function couldn't be used for developing some more permanent 'wisdom' on WWF; could be for dust extraction, could be for a range of things. Stuff that is from forum members and shouldn't be lost in old threads. E.g. I saw a beauty last night, someone who a while ago had posted perfect (better than the manufacturer's) instructions for setting up a particular model of bandsaw. Ideally it would be in a Wiki, not just an old thread. So far it is an unutilized facility here on WWF.

Gunna

[Skew ChiDAMN!!]

It seems to be a common misconception that plugging anything into a DC makes it more efficient. "It must; it has more suck!" So I think I'd like to see a section added along the lines of:

Using a hand-sander or similar tool with a dust collector will NOT improve it's dust extraction capabilities.
Tools with <2"(ish) extraction ports are designed for use with shop-vacs, while those with 4"(ish) ports are designed for DC's. One system uses low volume with high pressure, while the other uses high volume with low pressure. Typically, using the wrong 'sucker' with the wrong sized ports actually decreases the dust scavenging efficiency.

Well... not the best choice of words, but you get the idea?

[BobL]

It seems to be a common misconception that plugging anything into a DC makes it more efficient. "It must; it has more suck!" So I think I'd like to see a section added along the lines of:

Using a hand-sander or similar tool with a dust collector will NOT improve it's dust extraction capabilities.
Tools with <2"(ish) extraction ports are designed for use with shop-vacs, while those with 4"(ish) ports are designed for DC's. One system uses low volume with high pressure, while the other uses high volume with low pressure. Typically, using the wrong 'sucker' with the wrong sized ports actually decreases the dust scavenging efficiency.

Well... not the best choice of words, but you get the idea?

And one also needs a bigger picture and to be a bit more specific about what sort of vacuum cleaner one is referring to. Healthwise it is far better to use a power tool connected to a DC that vents outside the shed - (even if the DC is a crappy one) than most vacuum cleaners that vent inside shed. At least the first one is removing fine dust from a work area whereas the other one is not. Because vacuum cleaners have a very restricted duct lengths they cannot normally vent outside a shed. Yes, there are high quality and expensive vacuum cleaners that will trap the fine dust but I reckon if one spending that much money it is better to spend it on a bigger DC that vents everything outside the shed. If one cannot vent outside then an expensive vacuum cleaner is about the only thing available for power tools

The trick to using a DC with a power tool is to have two ducts open - one connected to the power tool and one free to atmosphere nearby to help collect the fine dust in the shed. This also allows the DC to operate closer to spec than it otherwise would.

I sometimes connect my 4" makita portable belt sander to my 3HP DC with 6" ducting and have a 6" port open nearby. This in fact works visually and health wise far better than a cheap vacuum cleaner I threw out when I got the 3HP DC.

[BobL]

I have a question, might seem to be from left field, but I have a reason. It'll be easier to ask the question first and hope to get an answer and then explain later. Is there air quality monitoring in High School workshops in Australia? Metering invisible dust in particular I mean.

Metering invisible dust in such environs could be problematic
- a room full of grubby teenagers with dandruff, playground dust and remnants of their last smoke are liable to set off all sorts of alarms.
- given the amount of work they do probably isn't going to generate much wood dust to begin with.
- I'd be more worried about the teachers having to deal with recalcitrants, broken machines and tools than dust.

[Groggy]

If a room full of teenagers working wood is nothing to worry about, why should a single woodworker in his shop worry? This statement seems inconsistent with previous concerns.

[BobL]

If a room full of teenagers working wood is nothing to worry about, why should a single woodworker in his shop worry? This statement seems inconsistent with previous concerns.

Sorry forgot the emoticon - I have added it into my post.

On a more serious note, in the overall scheme of things and from a completely practical viewpoint, given what they do, the average student doing 90 minutes of that sort of woodwork a week has relativley little to worry about.

The people I do worry about are the teachers who are exposed for much longer and I guess we are supposed to be teaching for life so it makes some sense to incorporate best practice into student programs.

Like I said be careful what we wish for. If the OHS nutters get their hands on this there won't be any manual arts in schools.

[Gunnaduit]

Maybe, on WW teachers, it depends on what the Australian (or the various state?) regulations are with regard to exposure limits for airborne wood dust. Does anyone here know? If WW teachers are being exposed above statutory limits then OSH is fair cop.

It has certainly been difficult while researching for the Wikipedia page to find the evidence that would vindicate all of BP's warnings. Two or three topics I would mention in particular:

- I still haven't really found anything about respiratory function decline as in particular due to sub-micron dust. Of course, there are quite a lot of studies attributing health problems due to wood dust in general, but not specifically sub-micron wood dust.

- On the air quality engineering side of things, I haven't found anything specifically about capture of sub-micron dust at the machine hood, as opposed, again, to wood dust in general. This is important in as far as BP says that the ordinary standards e.g. from ACGIH, are too low, and all the flows need to be raised to capture sub-micron dust. Not being an air quality engineer myself, I wouldn't know. And when I tried looking at quite a variety of AQE texts, I come up with nothing on this specific issue (there's a fair bit on wood dust extraction in general though). So then, working through that, what of the advice on ducting, i.e. 6" to all machines, no reductions toward the hood?

- No studies that I've found investigate airborne particle dynamics for particles of different sizes. So the whole area of escape velocities, capture velocities, duct velocities etc for different sizes of particles, it all seems a mystery.

Bob, you have mentioned here that you've worked in related fields; so some patient, spelt-out clarification is needed here, I think. More than the usual general assertions as on BP, more than you would read in an AQE textbook; dealing specifically with the issue of why and how sub-micron dust is different from larger dust in terms of hood capture and ducting.

So while I still think that it is worthwhile raising awareness about wood dust hazards, and that there are definitely health hazards from cumulative exposure, and, further, I am glad I've learnt the simple lesson not to recycle air within the workspace, I would like to see more independent evidence and advice as to sub-micron dust hazards, as opposed to wood dust hazards in general.

[mic-d]

The people I do worry about are the teachers who are exposed for much longer and I guess we are supposed to be teaching for life so it makes some sense to incorporate best practice into student programs.

Like I said be careful what we wish for. If the OHS nutters get their hands on this there won't be any manual arts in schools.

Yes I agree with both your points Bob. I've been trying to write a reply to explain where I was going, but failing miserably by sounding too extreme when I really want to say something quite moderate. Perhaps I had a mild stroke last night.
Let me try again... I'm not raising the question of what happens in schools to make that a focus... not really... because of the point above you raise, but... hmmm it is to do with credibility. I'm for the dust FAQ's on wwf, at least the referenced health risks. But when it comes to design and implementation questions, a reader would be right to be circumspect about information from the internet. Certainly there are few on here with the credentials to have confidence in their information. It's not to say the information may not be the best, as for eg Bill Pentz's site, but it's about how do you cut through to the audience and get their attention.
Now I have a mate, who's no dill and he researched about DE systems quite a bit both online and by talking to people, but when he set up his workshop dust extraction he had a DE engineer design it. That guy was from a company that do installations in schools, other institutions, commercial and probably govt too. My mate thought that because they install in schools, they must offer the best advice and designs and do it right, right? (mild sarcasm here) After all kid's health is pretty important, right? But it turns out that in the Bill Pentz universe, the system he got is theoretically inadequate from the dust collector spec to the duct sizing to the size and number of ports on the machines. Now gunnaduit (was it?) raised the possibility of agitating for Choice magazine to have a look at the whole dust extraction question, but are they really going to be interested? But they or someone might be interested if the focus was what happens in schools. And that is not a can of worms, it's an absolute Pandora's box nightmare to go there, but should we? By extension from my mates DE setup, do we really know what the air quality is like in schools (for teachers with longer exposure times, say), is there an Australian standard and is it even adequate? And this is why I asked the question about metering in schools, not real time metering, but calibrating after installation or auditing air quality some time down the track while the workspace is under a normal workload. My guess is none of this exists (and possibly it doesn't need to). Probably the vendor is relied upon to install an adequate system. Probably they do provide correct or over spec'd extractors, collectors, filters, ducting, but do you think they would modify machines which have dinky single small dust ports - probably not. Which lets the whole side down. Would it be such a Pandora's box if air quality was investigated and found wanting because of that one weakness? It's probably fixable without stopping manual arts all together and it's a business opportunity for some enterprise, and if change was required it would teach a new generation about improved requirements for dust extraction and education after all was what the posters here wanted anyway. Would it be a really bad thing to go there (what happens in schools) if that is what was needed to get traction in this whole area?

So in summary, who do we trust to give us the best info or how do you provide the best info and get people to trust it is probably a better way to put it. I'd like to see how the standard bearers in the industry perform, but to do that, you open up more than a can of worms. But if the next generation is being exposed to sub standard practises is that not just going to perpetuate those sub standard practises if they go on with woodwork in say, the home environment? And in real terms does the incessant drive for harm minimisation by narrowing and narrowing "safe' endeavours continue to reap a cost benefit reward?

The vibe of where I stand could be summarised by this quote from Helen Keller:
“Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure, or nothing.”
― Helen Keller, The Open Door

Don't take that as to say I think we should be cavalier about everything, but when I was caught under my sail underwater and in my harness the other day, I wasn't thinking about whether dust exposure is going to get me in 10 years time, nor did I think later that that was going to stop me sailing...

Probably I have just said in 1000 words what you said with "careful what you wish for..."

[Groggy]

...but when I was caught under my sail underwater and in my harness the other day, I wasn't thinking about whether dust exposure is going to get me in 10 years time, nor did I think later that that was going to stop me sailing...

Surely you must have thought 'I need a sign that says "this way up" '

[BobL]

Bob, you have mentioned here that you've worked in related fields; so some patient, spelt-out clarification is needed here, I think. More than the usual general assertions as on BP, more than you would read in an AQE textbook; dealing specifically with the issue of why and how sub-micron dust is different from larger dust in terms of hood capture and ducting.

My experience has been in design and construction of ultra clean labs for chemical analysis. This is different from woodworking in that it involves keeping outside air and dust outside the facility and constructing the facility so that it makes as little dust as possible. BEcause these are chemical labs the chemicals tend to corrode metal so that we avoided metal and used epoxy covered wood and plastic instead.
We started out working with local engineers - the closest thing these guys had built to this was hospital operating theatres but we kept telling them - no metal and it has to be 100 times cleaner than a hospital operating theatre. For many months we got know where mainly because the engineers did not understand what we wanted and kept bringing in consultants to tell us what we could have. So we hired our own consultant from the US. In one 1 hr meeting between him and the engineers we got what we were after although putting that into practice was still a mighty effort.

Of course there is always some dust is generated inside these very clean labs but whatever is produced is rapidly scrubbed and remove using high volume high capacity HEPA filters. Woodwork dust generation is different because it is characterised by extreme pulses of dust making that need to be removed as much and as quickly as possible at source.

The air filtration of these clean labs itself was never the main aim of our research so although we did a lot of experiments with monitoring and moving air and dust but unfortunately we never published anything on it. Most of what I say is from a gut feel about what I think happens backed up by a few experiments (like the ones on vacuum cleaners and how the human body acts as a thermal funnel).

For example ultra clean room operations require that when any dust that is generated to be grabbed ASAP before it can interfere with experiments. This is why whole banks of relatively low air speed <600 fpm down draft HEPAs are used to line ceilings and the airflow is made as Laminar (smooth and even) as possible. This idea is not new and has been around since the first computer chip factories in the 1960s - the difference between computer chip factories and our setup was we had to also keep the lab as metal free as possible.

The reason for such low air speeds is so that the air flow is not turbulent and dust will move in a steady unidirectional flow. We did a lot of work to confirm this as it is a real problem for us. We would like to have much higher flow rates but as soon as we did this the turbulence set it and we found many particles moving counter to the air movement. This comes out when I talk about dust movement cause by air currents generated by moving blades such as band saw blades and the placement of barriers and edges generating turbulence and dust movement. It helped me confirm things like the location of external DCs and the associated placement of make up air openings to the shed. It also tells me why large fans running inside a shed will just stir up dust and it is far better off to place pairs of fans on opposite walls of a shed and run is such a way to push fresh air into and pull dusty air out of a shed. Like I said, we studied many aspects like, types of materials and paints, speed of door openings, lab personnel movements and placement of lab furniture etc etc.

Our steady laminar flow has been set up to so that it moves dust and air down into false/perforated floors and walls and then back up to plenum in a false ceiling and then back out through the HEPAS in the ceiling. Our standard labs (7 ft x 9 ft x 15 ft) have air turn overs approaching 5000 cfm while our big lab has a 15,000 cfm turn over. Each small lab has 7 ,1200 x 600 mm 99.997% at <0.3 microns HEPAS in the ceiling while the big lab has 36 of these HEPAs. The air for these facilities undergoes 1 stage of pre or coarse filtration followed by 3 stages of HEPA filtration which produces air for the critical working spaces in the lab that has a theoretical working particle density of <0.001 particles of 0.3 microns or larger, per cubic ft of air but we could not measure this as our particle counters just read zero in these spaces. The lab cost Australian Taxpayers and the University about $3,000,000. The lab won an Australian Engineering design award and everyone that tours it says it is the best lab of its kind in the world.

One thing we did not look at in detail was ducting - we used large cross section often rectangular ducts and our main fume hoods used 300 mm pipe so we never had a problem. This is why I too started out with 100 mm diam duct on my first DC and it was only after finding my shed filling with dust and reading BPs site that I realised ducting is one of the big issues in DE that is so poorly understood.

So to sum things up.
I learnt a lot from working on these and other labs, but the specific design would be totally impractical for for woodworking as the filters would just fill up with dust.
Nevertheless there are plenty of good ideas and principles in there somewhere.
Everything we did showed that the invisible particles behave like a gas and are very, very difficult to direct and capture.

I'm sorry about the long ramble I don't know if that answers any of your questions or not.

[BobL]

Just before writing the previous post I was up the Uni library and decide to take a look at the Australian Standards for wood dust in air.

The 1995 standard I believe is still the one in place. It has two wood dusts listed (hard "like beech and oak" and soft wood) and two exposures, one called a TWA (Time weighted average) and a STEL (short time exposure limit).

For softwood the limits are 5 ppm for TWA and 10 ppm for STEL. For hardwood there is a 1 ppm TWA and no STEL listed. There is no micron rating listed anywhere in the document.These are the same or similar to US and European standards. The UK standard is 5 mg/m^3 for an 8 hour period. Hardwood is listed as a carcinogen in the EU. The US limited are listed here.Safety and Health Topics | Wood Dust Once again there is no micron ratings listed anywhere in these document.

For visible dust, a rough check of this is possible for a shed. Place a piece of sheet goods marked out with a 1 m^ square in it in a in a suitable place - make the dust for 8 hours and then come back the next day and very carefully sweep up the dust and weigh it. Now you need a $15 electronic (drug dealing ) balance from ebay with 0.001 g resolution. Multiply the number you measure by say 1.2 to account for invisibles and you will have a good ideas how good your setup it. Of course if you are using MDF you should multiply by about 2.5.