Shop Fire Safety #1: Hazards in the Workshop

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Blog entry by PocketHole69 posted 06-21-2010 05:59 AM 15034 reads 1 time favorited 8 comments Add to Favorites Watch
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This was originally a comment on this forum thread. I’m posting it again here so more people might see it and avoid serious fire and safety issues in their shop.


I’m a firefighter and the head of the emergency response team for a company that specializes in industrial fire protection. Before switching to the industrial side I worked several years as a municipal firefighter.

First of all, the original posters assumption that the risk of fire in a wood shop is low is completely wrong. There are a number of hazards in the wood shop that are unique and in many ways more dangerous than other sources of fire in the home such as kitchens and garages (the two top problem areas in most homes).

In no particular order, these are:

1. Combustible Dust

Wood boards / chunks / pieces just burn and are easily controlled with extinguishers, or in a worst case scenario easy to get away from (run). In contrast, combustible dust in an unconfined area flashes and ignites nearby flammable surfaces, potentially setting fire to large portions (or all) of your shop. Combustible dust in confined areas (such as small rooms, dust collectors, paint booths, and tool enclosures) explodes.

Combustible dust explosions kill people. They are a top safety concern of OSHA with recent high-profile incidents such as the sugar plant explosion in Georgia. It doesn’t take much dust to do it either- as little as 1 pound floating around your shop in the air can provide the perfect fuel-to-air ratio for an explosion. The fact that many shops are in basements, utility rooms, and garages where there are ignition sources such as water heaters and furnaces nearby, as well as unshielded tools and frayed cords arcing is the perfect recipe for disaster.

Sources of combustible dust in the wood shop include sawdust, dust collectors, metal dust if you’re in to metal working, and lint / paper products.

The best defense against combustible dust is good housekeeping. Clean up after yourself and don’t let dust accumulate. Try to do your woodworking away from possible sources of ignition and open flame such as pilot lights.

Many will argue for dust collection in the shop, and a well implemented dust collection system can minimize the risk. However, dust collectors pose special hazards of their own and dust collector explosions can occur when a burning bit of sawdust gets introduced to a huge bag of floating dust inside the collector.

Most dust collector fires in industrial settings get out of hand when the dust collector ignites and explodes, and then because of bad housekeeping all the dust outside the collector, shaken up and sent airborne by the dust collector popping, gets ignited by the dust collector explosion. This one-two punch levels buildings, as the video linked below will show:

Combustible Dust: An Insidious Hazard
(Youtube, 30 minutes long. Probably more than you ever wanted to know about dust)

2. Paint / Stain spray in the air and buildup on surfaces

If you want to make something really damn hard to put out when it catches on fire, put about 10 coats of old paint or poly on it. Also spray painting creates the same hazards as combustible dust when in the air.

Use a paint booth or spray outside. Clean up your mess.

3. Metalworking

Metalworking creates metal shavings and dust. Metal shavings and dust burn when they get hot, and metal working is known to create heat.

If you have a metal fire you can’t put it out with a common Class ABC dry chemical fire extinguisher. They burn ridiculously hot so you might not even be able to approach them to drag whatever is burning out of your shop. Spraying water on metals fires usually causes an explosion because they burn so hot that they catalyze the water in to Hydrogen and Oxygen (a flammable gas and an oxidizer to accelerate combustion), causing a violent ignition.

If you work on metal with any regularity and don’t have a Class D fire extinguisher handy you’re asking for your house to be burnt down. Most municipal fire departments, and especially rural volunteer departments, are ill-equipped to handle a metal fire. At the very least you need to have a bucket of sand nearby so you can cover up and slow the combustion process and try to prevent radiant heat ignition of the rest of your shop until the fire department arrives.

4. Oily rags

Oily rags that contain oil, finishes, paint, etc. go through a process of biological and chemical decomposition that creates heat. This decomposition occurs everywhere, even in rags sitting on your workbench exposed. This is a tiny amount of heat- it normally just dissipates in the air and is not even noticed. The problem comes when they are stored in a closed container with other oily rags- the heat can’t escape. When the heat can’t escape it in turn speeds up decomposition, which in turn creates more heat, which in turn speeds up decomposition, etc. until the rags reach the auto-ignition temperature of the rags or chemicals they contain, causing them to spontaneously ignite.

The scary thing about this is you don’t have to be in your shop for it to happen- you can do your finishing, go to bed or work, and then 8 hours later while you’re sound asleep the rags can reach ignition temperature and light your house on fire. It might take days for rags to reach ignition temperature, and having your house burn down while you’re at work really sucks from what I’ve heard.

At the minimum you should store oily rags separate from other waste and remove them from your house when you’re done. Better is a metal can with a tight fitting lid that can contain a fire and starve any that might start of oxygen. Best is a OSHA approved container that is rated for storing oily rags- they really aren’t that expensive when you think about what is at risk (your home and your family)

5. Location

Where a fire starts in your home has a lot to do with if the fire department is going to be able to save your house and everything you own.

The two absolute worst places for a fire to start? The basement and the garage.

Where are many home workshops located? The basement and the garage.

When a fire starts in the basement you have about a 50/50 chance of losing your home, and even more so if your basement is below grade. Basement fires are hard to approach- heat rises so a firefighting going down a staircase to the basement is going to get cooked and may not be able to make it. Basement fires compromise the floor structure of the first level of your home, making firefighter entry in to your house a dangerous proposition. Some fire departments won’t even enter a home when there is a basement fire burning- they don’t want to see their men step on a soft spot in the floor and fall through in to an inferno.

Garage fires are dangerous for obvious reasons- people store flammable stuff in garages: paint, gas, chemicals, cars full of gas, etc. If garage fires are not quickly controlled they can quickly burn out of control, and with most garages attached to houses in the US the rest of the house is just one minimum code requirement wall away.

What can you do to minimize risk?

Those are the major threats. Here is what you can do to minimize the risk:

1. Have a fire extinguisher appropriate to the materials in your shop

You should have, as a minimum, a 5 lb. Class ABC dry chemical fire extinguisher in your shop. You should have one in the garage and kitchen too.

If you are working with metals, you should have some Class D extinguishing agent nearby.

If anyone is wondering what the fire classes are, they are:

Class A: Ordinary Combustibles (wood, paper, etc.)
Class B: Liquid Fuel Fires (paint, stain, gas, etc.)
Class C: Energized Electrical Fires (power tools, wiring shorts, etc.)
Class D: Metals Fires

Read up more on Fire Classes

2. Clean up after yourself

90% of workshop related fire threats can be negated by cleaning up after yourself. A dirty shop is not just messy, it’s unsafe. Your momma was right when she told you to clean your room.

Regularly clean up dust after working with wood products. Clean up spray booths and ventilate after spraying finishes. Take out your trash, and store oily rags properly.

3. Look around and realize what your hazards are

In the fire department we call this a pre-plan, and most business locations have one on file with the department so they know what they’re walking in to. As a home workshop user, you can do your own to recognize the hazards and minimize the risk.

Do you have a pilot light nearby that could light dust next time you’re sanding? Do you have frayed cords or overloaded outlets that can arc and start a fire? Do you have exposed electrical wiring? Do you have a pile of oily rags in the corner by your wood pile?

What can you do to minimize the risk to your home and family? Everyone who’s house burnt down never thought it could happen to them, but one day everything they owned, their pictures, their memories, their pets, and sometimes even their family members were gone. Nearly every house fire I’ve been to could have been prevented. You owe it to yourself and your family to take a minute and minimize the risk of fire.

4. Install a fire alarm

Really, this is a no-brainer. You should have a fire alarm in your shop, in your kitchen, in your garage if different from your shop, and outside every bedroom on every story of your home. Central monitoring is great if you can afford it, but at the very least get one that will go off and wake you and your family up if there is a fire.

-- Jason, Atlanta, GA

8 comments so far

View lightweightladylefty's profile


3538 posts in 4448 days

#1 posted 06-21-2010 06:39 AM

Thanks, Jason, for a good reminder. Having been through two fires in my lifetime, I know what a horror it is. I reduced the chance of the one kind I had (burglary and arson) by moving out of the city. The second one was a freak accident when we were building our home and my husband moved a can of white gas for camping that hit a battery with side-mounted posts and immediately ignited. The Lord spared our lives, and the damage was not as extensive as if could have been, considering we are 5 miles from an all-volunteer fire department.

Your information is very thorough and well appreciated.

-- “Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.” Benjamin Franklin -- Jesus is the ONLY reason for ANY season.

View wichle's profile


96 posts in 3683 days

#2 posted 06-21-2010 07:05 AM

And everyone thinks I am anal about clean up. I have been asked if I ever do anything in my shop. Something I learned from my dad who religiously ckeaned the shop when done and ready to hit the sack. I do wish my dust collector was outside but that’s not possible here. I have a basement shop.

Good reminder goo article.


-- Bill, Michigan "People don't come preassebled, but are glued together by life"

View a1Jim's profile


118047 posts in 4313 days

#3 posted 06-21-2010 07:51 AM

Thank you Jason
All great information, all points well taken.


View dbhost's profile


5777 posts in 3968 days

#4 posted 06-21-2010 05:35 PM

Points well taken. No projects in my shop presently until cleaning is complete… Now projects OUT of the shop is a different story all together…

-- Please like and subscribe to my YouTube Channel

View Dennisgrosen's profile


10880 posts in 3851 days

#5 posted 06-21-2010 09:48 PM

thank´s for posting this again Jason
I remember one fireexplosion from dust
in a compani that handle corn of all types
they usualy blow the corn from silo to silo
to cool it and that gives a lot of dust building
up in engines and in the basements
there is two compani´s of those on the harbor
were I lived before + a compani that made every kinds of
oil to the foodindustri and a big oil/gasoline depot
I don´t have to tell you wistch kind of compani the firedepartment
was most afraid of…...........right the companies that handle cornproducts

View Hacksaw007's profile


620 posts in 3925 days

#6 posted 06-21-2010 09:56 PM

Can’t post this stuff enough, thanks! We were told in at Pennsylvania House Furniture, that is isn’t the first explosion that kills you it is the second one. The one where it knocks down all of the dust on the pipes, lights, building beams, and what is in your dust collection and so on. Saw some films on this and they were scary. Seen a small explosion one day when my 90 year old grandmother was cleaning up and threw in a shovel full of dust in the wood stove in my shop. She nearly lost all of her hair. Needless to say having a wood stove in your wood shop isn’t the best thing to have either….....

-- For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. John 3:16

View noknot's profile


548 posts in 4177 days

#7 posted 06-23-2010 01:09 PM

Thanks for posting this again everybody has to learn about this it could save a life


View Just_Iain's profile


322 posts in 1152 days

#8 posted 07-22-2017 04:18 PM

I’m going to bump this with a link to a good youtube take on a small fire-resistant cabinet to build yourself. Is it absolutely fireproof (No) but the idea is to buy you some time to escape when ‘all hell breaks loose’.


-- For those about to die, remember your bicycle helmet!

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