Fire Hazards

Hello!

I was reading a good woodworking book last night and I came across a thorough discussion of fire hazards. I was surprised to learn that the hazards are not just the ones with combustible/flammable chemicals, but that there is a real risk of a spark igniting airborne sawdust......and piles of sawdust exploding into flame......

So I'm wondering if anyone has ever experienced something like that or known of any stories like that or if the discussion was grossly exaggerated?

thanks,
cynthia
 
Oh yeah, Take a handful of saw dust out to the burn barrel and throw it on the open flames...stand back though. Actually don't do that unless you feel safe doing so and be sure to be up wind. ;)

Actually it's been said many times that if you use PVC for dust collection tubing, be sure to run a ground wire in and out of the tubes every once in a while to discharge static. Don't know if anyone has ever been bit by a spark in that type of setup, but in concept it makes sense.

I try to pickup the shop each night and keep the dust swept up, have seen fire spread via sawdust it's pretty scary.
 
Last edited:
I had a dust collector fire once, but it wasn't from the dust, it was a capacitor on the motor that went bad. I was running the DC and all of a sudden noticed smoke in the garage. Fortunately, I got to it quickly and hit it with a fire extinguisher before anything more could go up than just the cap.

Been paranoid about having fire extinquishers ever since. I've got a couple of the larger sizes mounted in the shop and a couple of smaller ones setting in handy places. Whenever I'm grinding something, or welding, I make sure I have one of the smaller ones right handy.

I also make sure I sweep up any dust before doing those kinds of tasks. Also a good idea to put any flammables chemicals far away as well.

I finally sorted through all my solvents and paint supplies and was shocked how much I had. For christmas, I'm getting my self a metal storage cabinet to keep all that kind of stuff in...
 
To answer your question Cynthia I have experienced something similar at a shop I worked in when I lived in Baltimore. The shop was heated with a hot air furnace that used scrap wood or coal to make the heat. Well one winter it was so cold we ran out of scrap wood and started to burn the coal at the bottom of the pile. Well one shovel of coal will last pretty much the whole day and burns very hot! Well someone put too much coal in the furnace and it made the air hot enough that all the dust that was in the ductwork ignited. Lets just say a bunch of us needed to check our drawers when we herd the boom and saw the smoke come out of each register.:eek::eek:
 
This is the main reason that I bought a good dust collection system. Dust in the shop is really dangerous and all it takes is one spark to set it off. Insurance companies may have issues if you are setting up a shop inside your home without one. saying that we had a dust bin fire at work where a small chunk of metal went through a machine and sent a spark into the bin outside. No one thought much about it and it smoldered for hrs before it caught on fire. If it had been after hrs the entire shop could have gone up.
 
It's my understanding that if sawdust concentrations in the air are high enough to present a fire danger, the fire is the least of your worries...the airborne dust is a bigger threat to health and life. Yes, you can throw a handful of sawdust into a fire and create a big flash, but the chances of having an explosive concentration of dust present in your shop during the course of normal woodworking activities are pretty slim. Doesn't mean a person shouldn't be cautious and aware of any anomalies (like a chunk of metal going through the dust collector), but the typical woodshop isn't a bomb waiting to go off.

On the issue of PVC dust collector lines and static electricity sparks, I no longer recall the source, but I read an article a few years ago arguing that it's virtually impossible to get the right combination of dust density and oxygen in a DC line to support a fire caused by static electricity. The article also claimed that there have been no documented cases of static electricity igniting a fire in a home shop DC line.
 
It's my understanding that if sawdust concentrations in the air are high enough to present a fire danger, the fire is the least of your worries...the airborne dust is a bigger threat to health and life. Yes, you can throw a handful of sawdust into a fire and create a big flash, but the chances of having an explosive concentration of dust present in your shop during the course of normal woodworking activities are pretty slim. Doesn't mean a person shouldn't be cautious and aware of any anomalies (like a chunk of metal going through the dust collector), but the typical woodshop isn't a bomb waiting to go off.

On the issue of PVC dust collector lines and static electricity sparks, I no longer recall the source, but I read an article a few years ago arguing that it's virtually impossible to get the right combination of dust density and oxygen in a DC line to support a fire caused by static electricity. The article also claimed that there have been no documented cases of static electricity igniting a fire in a home shop DC line.

It still smarts touching a hose or pipe when it is charged. I'm not taking any chances Vaughn and there are articles out there that still talk about this. 6 of one half dozen of the other. Better safe than sorry. I don't know about your shop Vaughn but i am still cleaning up concentrations of dust even after installing the DC in the shop as it doesn't catch everything.
 
Plenty of stories. Many industrial boom-booms where regulations are lax or just not followed. There is a You Tube video of some guys making a terrific looking "explosion" by launching sawdust into the air via some sort of compression and igniting the cloud.

Certainly piles of sawdust in the shop are a no-no. I know there are folks who think a messy shop means they are creative or busy but, it is really just messy and potentially dangerous.

In the never-ending discussions about static discharge, just fix it. I just ignored it till a re-route of one main put it where I touched it more often than before. You can find what you need in the junk drawer or buy it at the big box for under $20. All you are doing is providing a path to ground that is easier to get to than you are ;-)

I wrapped a piece of 18ga. stranded, insulated wire about one turn per foot along the mains. I clipped it to a metal conduit box, which is properly grounded, at one end via a hanger strap

duct-hang-grnd 002.jpgduct-hang-grnd 001.jpg

and to a "plate" of foil tape stuck to the concrete at the other; all sign of static discharge are gone.

G0440-ground-005.jpg
 
It still smarts touching a hose or pipe when it is charged. I'm not taking any chances Vaughn and there are articles out there that still talk about this. 6 of one half dozen of the other. Better safe than sorry. I don't know about your shop Vaughn but i am still cleaning up concentrations of dust even after installing the DC in the shop as it doesn't catch everything.

I'm not saying grounding DC lines is a bad idea, I'm just saying that there doesn't seem to be any real evidence of DC fires being started in home shops due to static electricity. I've also got some serious concentrations of dust in my shop, but I don't have airborne concentrations with the right mix of dust and oxygen to be an explosive risk. (I doubt anyone here does.) The piles of dust on the floor and on shelves might be deep enough to burn if ignited by a source like a dropped cigarette ember or grinder spark, but not a static electricity spark.

I know what you mean about static shocks being painful, though. When I'm using buffing wheels mounted on my lathe, I get lots of static discharge. I have to keep my leg or knee touching the lathe bed (or another suitable ground) or I'll get a mean shock when I do touch it. I once took a miniature lightning bolt to the...um...well...to the place where most guys wouldn't want to be shocked. :eek: That was my wake-up call. :rolleyes:
 
I agree with what Vaughn said. This is a highly emotive subject and i think the internet just drives it further up the wrong scale.

A dust explosion is hard to achieve in a shop and if one is working in an evironment like that one needs their head read.:huh:

I do think the aspect of a fire in a dust collector bin is a real one to consider.

But as Glenn says keep the shop clean thats just as good as saying use a push stick or ear plus or eye protection.

I think the aspect of static in a shop is another issue that should be addressed. Newtons law states "For every action there is an equal and opposite reaction" So just the same as someone disturbing you while you doing something at a machine the same can go for static if it hits you and you suddenly react which you will, the wrong way.

BTW i tried unsuccesfully to discuss this issue with the local Chief Fire officer and he was not having it. They have dust explosion fobia in the code so thats what he is interested in. When i talked to him about the health and safety aspect as in breathing the stuff in, well lets say he was not that concerned what you do to yourself, but more concerned about what a dust explosion would do to the NN.:rofl:
 
I agree with what Vaughn said. This is a highly emotive subject and i think the internet just drives it further up the wrong scale.

A dust explosion is hard to achieve in a shop and if one is working in an evironment like that one needs their head read.:huh:

I do think the aspect of a fire in a dust collector bin is a real one to consider.

But as Glenn says keep the shop clean thats just as good as saying use a push stick or ear plus or eye protection.

I think the aspect of static in a shop is another issue that should be addressed. Newtons law states "For every action there is an equal and opposite reaction" So just the same as someone disturbing you while you doing something at a machine the same can go for static if it hits you and you suddenly react which you will, the wrong way.

BTW i tried unsuccesfully to discuss this issue with the local Chief Fire officer and he was not having it. They have dust explosion fobia in the code so thats what he is interested in. When i talked to him about the health and safety aspect as in breathing the stuff in, well lets say he was not that concerned what you do to yourself, but more concerned about what a dust explosion would do to the NN.:rofl:

If it is in the code it is there for a reason and it obviously is a concern. Just like lots of the codes out there they deal with extremes but since the system relies on the codes we have to follow them. Agree or not it doesn't really matter as I have not won an argument with a fire chief yet when it comes to common sence over the codes. :D
 
I know what you mean about static shocks being painful, though. When I'm using buffing wheels mounted on my lathe, I get lots of static discharge. I have to keep my leg or knee touching the lathe bed (or another suitable ground) or I'll get a mean shock when I do touch it. I once took a miniature lightning bolt to the...um...well...to the place where most guys wouldn't want to be shocked. :eek: That was my wake-up call. :rolleyes:

That definitely got your attention didn't it... had that happen once myself.

When I was working in SF, my office had a cheap nylon carpet... when a salesman would come to see us, we would shuffle our feet through the carpet and then offer to shake hands.:).. usually resulted in an audible pop and a spark to the salesman's hands.:eek::eek:.. was a good deterrent to constant interruptions from salesmen.... to this day I still will slap the side of a file cabinet before I pull it open... and the file cabinet in my study is wooden. :rofl::rofl:

Closest I've ever come to a fire in my shop... I was boring a pepper mill blank and let the drill bit get hot... it dropped an ember from the bore into the pile of sawdust under the lathe... I had about a 3 inch circle of smoldering ash by the time I finally figured out where the smoke was coming from.
 
Last edited:
I have a sprinkler system in my stripping room and spray booth. With Fire extinguishers located around the shop. This keeps me complaint with the Fire Marcel. Every year I hear if shop going Boom Boom, I have fire retardant cases to keep my flammables in and I order my 55 gal stripper in thick plastic drums. We create dust but we also blow out the shop once a week.
The main case for a big Boom Boom is electric fans in windows by the hack finisher or cabinet shop who are not licensed.

Be safe all.
 
which reminds me, I have an inch or several of planer poo to deal with. got the planer back from the repair shop, I forgot to include my dust chute with it, so I have a new dust cover, but the dc hookup is on the old one... and I'm impatient, have to get the old one swapped back in all those cutting boards of late means I have a healthy layer of poo to deal with.
 
Top