Dust Explosions

[cabinetman]

This evening, 60 Minutes did a segment on dust explosions and fires at factories and OSHA's responsibility for employers compliance. The segment was more directed to how OSHA may carry some blame for the disasters.

One OSHA agent interviewed admitted he wasn't educated in the hazards of dust explosions. OSHA's comment was more toward the fact that the employers weren't maintaining a housekeeping program. I watched the segment and got unnerved about throwing the blame to OSHA. How do you feel about this?

I believe an employer should be aware of the hazards of his business and take extreme measures to provide a safe workplace, OSHA or no OSHA. In a production shop, especially a woodworking shop, the larger they are the more difficult it is to control dust. Most all have open bay doors for air circulation. Air exchangers are mostly useless. Dust collectors do collect much of the dust and debris, but there is that which is very light and gets deposited in areas not often cleaned.

In smaller locations, such as 1, 2 or 3 car garages, dust fires and explosions can occur under the right conditions. There are many sources of ignition as motors spark, plugs getting yanked out, etc. In addition to the combustible solids, add to the mix any volatile chemical fumes, and you have a viable source for trouble.

My suggestion is to do a regular cleaning in those hard to reach areas. Consider your location and look at the workspace. If you have storage areas above the floor, tops of shelves, garage door tracks, lofts, just about anywhere dust can and will collect, clean them out.
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[crokett]

How would cleaning settled areas help? My understanding is it is the suspended dust in the air that is the danger.

[dbhost]

That's some relatively good advice. However, just how much dust is too much? In my workshop (2 car garage converted, or at least in the process), I am spending a great deal of time and effort to control, and counteract dust, but the woodworking, as well as metal work, and refinishing tasks I perform in there, produce a LOT of dust (hence the major effort toward dust control and cleanup) as well as more than my share of VOCs.

I don't think my shop is all that different from most hobbyist shops, and probably more than a few home based production shops.

My biggest problem in my shop dust control wise is the ability to move lumber being stored to clean behind it. everything else is pretty mobile, and reachable, and cleanable... The shop vac does an amazing job of picking junk up.

No I my home workshop will never be 100% dust free, but then again it is a workshop, and not an operating room. For the most part though, I would consider my shop space to be a safe place to work. I put a LOT of time, effort, thought, and money into making sure it is as safe as I can make it.

The OP brings up a fascinating subject albeit indirectly. He encourages us to do something (keep clean and reduce dust) to help us work safely, and healthy. Something we all should think about...

[Russianwolf]

If you can provide documentation on a single dust explosion taking place outside of a DC in a home shop, I'll start listening.

The only dust explosions that I've ever heard about in a wood shop were in the DC unit itself. Which is fairly easy to nullify by proper grounding to prevent static build up.

[cabinetman]

How would cleaning settled areas help? My understanding is it is the suspended dust in the air that is the danger.

Settled areas can get unsettled, and yes suspended dust is a problem, even with a dust collector. If you do have a fire, you'd want the least amount of fuel possible, i.e. settled dust.
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[Tom Slick]

I didn't see the 60 Minutes report but I have experience in large dust collection / explosion control
just wanted to clarify a little:
dust in the air is an explosion hazard
dust in a pile is a fire hazard
one can lead to the other in a large enough setting

I installed a GreCon spark detection system on a 100hp dust collector after having a fire started inside a wood milling machine. The fire was started by a cutting tool hitting steel and the sparks hitting a pile of dust. That fire's embers were sucked into the dust collector where the dust is in suspension in the air. luckily it didn't create a subsequent explosion or fire. We had another fire right after the system was installed and the system worked perfectly. anyway the Grecon system was installed as asset protection, not because anyone told us to.

[cabinetman]

If you can provide documentation on a single dust explosion taking place outside of a DC in a home shop, I'll start listening.

The only dust explosions that I've ever heard about in a wood shop were in the DC unit itself. Which is fairly easy to nullify by proper grounding to prevent static build up.

Hey. do what you want. Your comment might sound to others like it can't happen, so, if you don't think it's worthwhile to keep the area clean, leave yours dirty.
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[Russianwolf]

Hey. do what you want. Your comment might sound to others like it can't happen, so, if you don't think it's worthwhile to keep the area clean, leave yours dirty.
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While I won't say it's impossible, the amount of dust that would need to be suspended in the air to allow an explosion is very large. There are many shops running without DC that have open flame heating in the winter and even in those environments (My uncle's shop, my father's before he passed away and mine before I got my DC set up that I have direct knowledge of) an explosion never occured that I've seen a report on, even when using sanders heavily which create the most fine dust (the biggest culprit).

I've read people suggesting about the possibilities of these explosions many times over the years and not one has any evidence of a single event to back it up.

It's the equivalent of saying, if you have a very dust house and stir up the dust when you have a fire in the fireplace, it'll explode. Nearly all dust is flamible, so woodshops are no more suseptible than any other dusty environment. possible, but extremely improbable (the lack of evidence supports me on this).

[eccentrictinkerer]

This site presents a lot of very good advice regarding dust and dustrelated explosions.

http://home.comcast.net/~rodec/woodw.../DC_myths.html

I sold explosion suppression systems for Fenwal Protection Systems for several years. There is very little chance for an explosion in a home system because it is extremely unlikely that you could get the perfect air-fuel mixture and air volume-velocity mix to create an explosive atmosphere.

[wardprobst]

Hey CMan,

Good thoughts, those that disbelieve in dust hazards just haven't experienced the down side. I worked in a custom furniture manufacturing facility in the mid 1970s and saw three fires. It was somewhat larger than most home shops but not a tremendous amount. Scary as all get out since they started near the finishing area. A few months after I quit OSHA wrote up 29 separate violations and this was before they got real serious.
I have an Oneida DC which cost as much as the majority of my power tools put together. But it's still less than a visit to the emergency room for burns or respiratory ailments.
DP

[Tom Hintz]

While researching a book I talked to several fire department authorities about potential dust explosions and none had never even heard of one happening in a home shop setting. While they said that the amount of dust that wold have to be suspended in the air and the tiny particle size necessary to support combustion would be very unlikely to occur in the home shop setting, they stopped short of calling it impossible. (One officer qualified that by saying they see some pretty strange things in home workshops....)
They did say that the biggest thing they see is dust buildup in unseen places like inside or near water heater or furnace burners where the normal ignition/burn function of those devices can catch the dust on fire and start an often unseen blaze that can spread quickly once it gets going. All of them said that this dust buildup was responsible for many shop-related fires.

[cabinetman]

This evening, 60 Minutes did a segment on dust explosions and fires at factories and OSHA's responsibility for employers compliance. The segment was more directed to how OSHA may carry some blame for the disasters.

One OSHA agent interviewed admitted he wasn't educated in the hazards of dust explosions. OSHA's comment was more toward the fact that the employers weren't maintaining a housekeeping program. I watched the segment and got unnerved about throwing the blame to OSHA. How do you feel about this?

I believe an employer should be aware of the hazards of his business and take extreme measures to provide a safe workplace, OSHA or no OSHA. In a production shop, especially a woodworking shop, the larger they are the more difficult it is to control dust. Most all have open bay doors for air circulation. Air exchangers are mostly useless. Dust collectors do collect much of the dust and debris, but there is that which is very light and gets deposited in areas not often cleaned.

In smaller locations, such as 1, 2 or 3 car garages, dust fires and explosions can occur under the right conditions.

The intent of this post was to open for comment the premise brought out in the TV segment about OSHA's responsibility (or lack of) in the tragedies of those factories that experienced explosions and fires. HERE IS THE SEGMENT.

This thread got slightly waylaid. There are those wanting to argue how improbable it may be for a home garage. After watching the TV segment and having experienced shop fires, and with lives and property at stake, I merely suggested a "heads up".
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[jhart]

I saw the program last night, and was feeling during the program that business owners should have some awareness of the potential hazards and should be taking steps to reduce the potential and not be waiting for OSHA to come in and give them a citation.
On the other hand, it was hard to believe that OSHA people were not trained to look for these problems.

[Daryl]

As a matter of course I have never heard of OSHA investigating and issuing citations for non compliance unless there was a major accident resulting in death or serious injury. It is the onus of the business owner to provide a safe work place.

[Russianwolf]

The intent of this post was to open for comment the premise brought out in the TV segment about OSHA's responsibility (or lack of) in the tragedies of those factories that experienced explosions and fires. HERE IS THE SEGMENT.

This thread got slightly waylaid. There are those wanting to argue how improbable it may be for a home garage. After watching the TV segment and having experienced shop fires, and with lives and property at stake, I merely suggested a "heads up".
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Actually your complete original post shows your 'suggestion' on preventing "dust fire and explosions" by cleaning all those out of the way dusty spots. Not just an OSHA question.

But on to OSHA. How many inspectors does OSHA employ? How many factories, mines, etc. are there in the country? Kinda hard for to visit every facility that may need inspecting. That's why OSHA is VERY dependent on employees informing them of unsafe situations so that they can come in and act on them. If no one is complaining, the facility likely won't be inspected until after an accident. Add to all the truely unsafe situations that should get OSHA's major attention, they also have to deal with people complaining about the height of desks being an inch too tall and chairs that conform to their bodies better.