Shop fires?

[JBark]

I'm wondering if anyone has any knowledge of what starts fires in woodworking shops. The guy I rent my shop space from is getting on my back about sawdust (shavings) because he is changing insurance companies and he says the agent wants to inspect my shop. I'm not a stickler for picking up the shavings, I never have been, but without spark there is no fire. I know some shops have fires but I always attributed them to carelessness of heating or ungrounded dust collection.

What cha ya'all think?

[Leo Voisine]

I think that if the insurance company says that they are not going to cover the policy, for whatever reason they state ---- that is what needs to be done.

ALL - other reasons are invalid.

Not being sarcastic!

It's just that - whatever reasons you find -- are not going to do anything to convince the insurance company that they need to listen to reason.

[Beamer]

Logic has no purpose to the insurance company, for sure

But as to what starts shop fires - all 3 pieces of the triangle must be present. Fuel, oxygen and spark.

It's nearly impossible to work in an oxygen free shop, so that one's a constant.

You probably can't say there'll be no sparks - lots of unconsidered sources of sparks still exist in a shop. They usually require outside forces like wonky electricity or a steel tool of some kind finding it's way into a concrete or stone floor or wall perhaps from vibrating off something that happens to resonate with traffic or something. Most folks think the spark is easily prevented but it's usually this leg of the triangle that surprises us most often. Is every switch in your shop magnetic? Do you cut all power completely to the entire facility when left unattended? Is the wiring 100% protected from abrasion/cutting/gnawing by critters? Lotsa unseen sources for potential sparks are out there.

And of course fuel. Well if you've got oxygen, and can't completely stop sparks, then your only defense is to eliminate the fuel. If there's nothing TO burn, nothing CAN burn. And since smaller pieces of wood light quicker and burn easier than big pieces, that sawdust you have is a valid concern. Short of putting in a sprinkler system (which is a symptom treatment, and a last resort, btw), you would do well to keep the loose dust to a minimum - not just in the insurance company's eyes but also from a personal safety point of view.

Leo makes a valid point - the insurance company trumps all in this situation.

[gomer]

Clean shop is a safer shop. Clean shop is a healthier shop. Clean shop is a better shop. Now if I could just live by my own words. I am concerned w/ lung dust more than fires, but both are good reasons for tidying up.

[dicklaxt]

I had a situation that could have become a catasrophe,,,,,,,,,,,,,I was doing a lot of router work making dados and pushing the depth of cut which slowed down the rate of feed.This caused the shavings to pile tightly behind the bit, an ember appeared and was smoldering in the dado pile up on several occasions which I quickly took care of ,no big deal right??? WRONG!!!!I had my dust collector going during this operation and I suckd up one of those little smoldering piles and deposited in the dust bin,this was right at the end of my day and I shut down and closed up.My shop was in the garage which has a refrigerator that gets most of the cold drink overflow.We had run dry in the house and I went to the shop to get a canned drink(it might have been a beer,smile) but when I opened the door I smelled the fire and smoke.I of course took care of it but from then on I tried to avert that in the future and even if I was not pushing the router operation it became a new habit to go back to the shop and check things out before retiring for the night or day for that matter.

Chit happens

dick

[brburns]

Beer saves the day again!

I don't tend to worry too much about fire. I try to avoid anything stupic, but I let the dust and chips pile up. I wish I kept it cleaner just for the sake of being clean.

[Knotty_Pine]

For a turner, I'd say a grinder for sharpening combined with the shavings sounds like a pretty good start to a four alarm. I keep a bottle of water in the shop for just such an occurrence, and I never grind and then close the shop, I give any sparks at least a half hour to flare up.

Lotsa folks think to have a fire you need oodles of sparks, I don't buy it. I've seen fires on the side of the road started by a single cigarette thrown out the window of a passing car. Sawdust and lathe shavings are likely drier than grass in Tennessee, lol.

TJ.

[Ruffnek]

John,

While I don't think the increase is very much, there is an increased risk of fire with sawdust and shavings present, just because they have to be considered tinder...the more tender present, the greater the chance that an ignition source will combine with it for a fire.

Somewhere, there should be published data on woodshop fires and the causes. I'm preparing to pull our camper to the lake so I don't have time to do a search but maybe someone else will.

[sawduster]

Fuel, oxygen and spark.

Actually, I think I would change that to read, "Fuel, Oxygen, and source if ignition." While sparks are a definite source of ignition, there is also spontaneous combustion and likely many other sources that should be considered. Still, take away the fuel and you're good to go. That would likely include sawdust, especially the finer stuff, and sanding flour and the like as they can easily catch a spark, and smolder for a long time before announcing themselves in a full blown blaze, likely long after you've closed up for the day.

[Beamer]

Jun 9, 2010 13:19:11 GMT -6 sawduster said:

Fuel, oxygen and spark.

Actually, I think I would change that to read, "Fuel, Oxygen, and source if ignition." While sparks are a definite source of ignition, there is also spontaneous combustion and likely many other sources that should be considered. Still, take away the fuel and you're good to go. That would likely include sawdust, especially the finer stuff, and sanding flour and the like as they can easily catch a spark, and smolder for a long time before announcing themselves in a full blown blaze, likely long after you've closed up for the day.

Good point, Jer! Spark was too limited, for sure.

[sachbvn]

Jerry,

Thanks for adding spontaneous combustion - I was just logging on to add that.

Sounds like a far-fetched idea, but it is serious - it can really happen. No, it's never happened to me, but I am a 100% firm believer in it.

Think about it - you apply CA to paper towels and look at the chemical reaction that takes place. I am no chemist - I can't verify that the dye or fibers in that old T-shirt I used to apply stain won't react with some solvent......

I work with mostly ladies - and being a known woodworker I get a fair amount of questions or asked my opinion on how to do something. Any time it involves staining or something to do with solvents - I make sure to tell them how serious spontaneous combustion is and that it can seriously happen.

I'm very good about laying out my rags and paper towels - but I really need to get a small metal trash can to put them after they dry.


Zac

[dcarter636]

I started a pile of sawdust smoldering with sparks flying from a chisel being ground on the belt sander, the rest of the story ran exactly like Dick's, smelled the smoke and doused the fire before retiring.

I would clean the shop up before an inspection and every day at quitting time. Keeping in mind that there are so many unanticipated events that can transpire, it is prudent to apply a bit of sensible housekeeping with solvents and other fuels in the shop. Much as I like the feel of walking on a carpet of chips and shavings, it is always on my mind that unexpected stuff happens and a fallen ash or errant spark could become a disaster.

[JBark]

Thanks guys. I put this out for food for thought for myself. Oddly I did know that shavings, oxygen and some form of ignition would cause a fire. I also wasn't looking to argue with some insurance guy who reads actuarials (is that how that is spelled) on what causes fires. I've been working in pro shops and my own for 20+ years and have never had a problem with dust and shavings, no matter how they were handled or not handled. I know of the problems in dust collection systems and static build up and of course metal working or grinding will give a real good spark to start combustion; no problem understanding that.

This is my shop; ground floor of an 18th century barn. Walls are one foot thick, humidity varying from a low of 75% to 150% during August (I swim.) Most of my motors don't seem anywhere near the shavings, jointer and planer being my worst offenders. Actually I can't think of any motors that are really near where the dust or shavings accumulate. Don't use a grinder nor any kind of sander on metal and the last time I thought I had a problem was using my mortiser when the shavings built up inside the chisel and smoked so I poured water on the shavings pile. The rest of the building is wood, old, old wood. Two hundred years of dust, bug eaten timbers and floor boards. Should I also mention the handyman that circulates the property, smoking, passing out drunk in the barn, etc.

Maybe I've been lucky and I should change my habits...but really, what are the chances of that?

[RiverWalker]

Jun 9, 2010 8:34:59 GMT -6 Knotty_Pine said:

Lotsa folks think to have a fire you need oodles of sparks, I don't buy it. I've seen fires on the side of the road started by a single cigarette thrown out the window of a passing car. Sawdust and lathe shavings are likely drier than grass in Tennessee, lol.

TJ.

exactly... start a fire with flint and steel and you'll see how little is really needed to get a serious fire going.only takes the tiniest spark on a piece of tinder. ... tinder like dry, extremely thin wood-type material.

I mean papery birchbark is great tinder, and looks a lot like plane shavings to me...

I wouldn't want to try to start a fire with fine sawdust alone though, not enough fuel in each piece of material to catch much, and too able to be compacted and have lacking oxygen... but in an accidental situation, would still be able to be prone to smoldering until it caught something that could actually burn proper.

some of what I've read about boiled linseed oil seems scary...

imo it doesn't sound like in your situation you are likely to have any problems. I'd be the most paranoid about stuff like grinders.

... that and the "handyman" possibly passing out with a lit coffinnail.