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Woodstoves and Flash Explosions

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Forum topic by TZH posted 01-21-2016 10:08 PM 1159 views 0 times favorited 31 replies Add to Favorites Watch
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TZH

526 posts in 2601 days


01-21-2016 10:08 PM

Topic tags/keywords: resource question carving shaping turning finishing joining sanding woodburning

In doing a bit of research on this, I was able to verify what I already knew about dust and/or sawdust causing flash explosions if sparked. What I haven’t been able to find anything on is whether woodstoves are a risk, big or small, for flash explosions.

I try really hard to keep my shop as dust free as possible even though I don’t have a conventional dust collection system. I use a leaf blower to get rid of sawdust by blowing it out an open door (gotta open and close it this time of year where I live) even during the work engaged in.

The issue is I have one of those jet heaters I’ve been using after having moved my shop from a heated building over to another building on our property that isn’t heated. The jet heater can’t keep up with the cold weather and I’m really anxious using it while creating sawdust doing what I do because it’s basically an open flame being thrown into the work space. Here’s a photo of the type of heater I’m talking about.

In any other environment, this heater has been more than effective for me. In a woodshop, the unknowns are a bit scary. So, we’ve decided to sell it and are considering putting in a woodstove. And that’s where this post is leading….to a question for all you more experienced LJ’ers as to whether a woodstove might be the way to go? I have no doubt it would heat up the shop and keep it warm enough while I’m working. The question is whether or not I run the risk of blowing myself up while doing it…...HELP!!!!!

Thanks for your feedback, suggestions, and recommendations.

-- Where The Spirit In Wood Lives On


31 replies so far

View TiggerWood's profile

TiggerWood

271 posts in 1067 days


#1 posted 01-21-2016 10:32 PM

I thought about putting a wood stove in the opposite corner of my garage but it just seems like the most dangerous way to heat a wood shop. I think it would be more likely to start a fire than your jet heater.

View cabmaker's profile

cabmaker

1506 posts in 2270 days


#2 posted 01-21-2016 10:44 PM

the jet heater as you call it…...i have been using for approx 30 yrs with out incident. I have never burned anything other than diesel in them.

View TZH's profile

TZH

526 posts in 2601 days


#3 posted 01-21-2016 10:59 PM

Thanks, guys. One thing I forgot to mention, too, is with regard to economics. Because my shop is not insulated, it seems the jet heater (not sure what the actual name is….I’ve seen turbo jet and portable, but would be interested in other names, as well) goes through an awful lot of kerosene fuel. During one cold snap, I went through five gallons in a matter of a couple of days, and the shop never really got all that warm.

Anyway, I also found a website forum (http://forums.finehomebuilding.com/breaktime/general-discussion/wood-stove-wood-shop) that kind of shows the wide range of opinions on this. I do appreciate you guys weighing in on it.

TZH

-- Where The Spirit In Wood Lives On

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pjones46

986 posts in 2104 days


#4 posted 01-21-2016 10:59 PM

I would not use the jet /torpedo heater due to Carbon Monoxide output in a closed space coupled with ambient dust explosion likelihood.

That being said, I have/do use a airtight wood stove for over five years without any incident but keep the shop vey clean. It is a great way to get rid of small cutoffs and scrape wood that would otherwise have to be thrown out at an extra cost and gives the benefit of heat.

Of course my shop is insulated very well and that in itself helps to keep the heat in. My shop is 24’ x 36’ with 10’ high ceiling all of which are insulated.

I also had to deal with cord wood to heat which was a pain as I got older, so, this year I put in a Propane way oversized 135K BTU airtight ceiling hung Modine Effinity 93 heater and have been very happy with it so far, but was not cheap to get and install.

-- Respectfully, Paul

View EMWW's profile

EMWW

23 posts in 374 days


#5 posted 01-21-2016 11:15 PM

I think that a woodstove would be fine. That is what I heat my shop with. A few things to cation you with are do not cut cost on the instillation and make sure it is as good as it can be. I learned this the hard way from seeing fires caused by poor installation. Also make sure you plan at least an hour on warm-up time depending on the size and insulation in your shop. I usually use that hour to clean up and to prepare stock. I hope this helps.

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TZH

526 posts in 2601 days


#6 posted 01-21-2016 11:21 PM

More very good information…..thanks.

The carbon monoxide thing isn’t something I’d even thought about!

Hoping others are learning as this discussion goes along. I know I am!

-- Where The Spirit In Wood Lives On

View conifur's profile

conifur

955 posts in 612 days


#7 posted 01-21-2016 11:22 PM

I worked for 20 years in a coal fired Power Plant, we pulverized the coal finer then talcum powder, it gets blown into the boiler section, it flash burns in there, we never had an incident at any of the 5 PP that are utility ran. I was at a safety demonstration at a old PP that was going to be destroyed/razed, they did a coal dust explosion in the facility, cameras ect, fuel air monitors, ect, for the air to fuel mix to achieve it the air had to be almost impossible to see through before they could get it to the right mix to flash explode, and they had propane torches burning as igniters.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View JoeinGa's profile

JoeinGa

7479 posts in 1468 days


#8 posted 01-21-2016 11:40 PM

I used to use one of these torpedo heaters in my shop. I always blew it out with compressed air before firing it up in the morning and then when I’d break for lunch I’d blow it out again. Never had even a hint of a problem that way.

Now I have this on a mobile stand that I welded up, rather than mount it at the ceiling. and I just move it to the area I’m working in. Works good.
.
.

-- Perform A Random Act Of Kindness Today ... Pay It Forward

View AandCstyle's profile

AandCstyle

2566 posts in 1718 days


#9 posted 01-22-2016 12:04 AM

TZH, I have always called them salamander heaters. You should be okay with an air tight wood stove, but do NOT toss saw dust into one when it is burning, because the dust can be explosive. Also, check with your insurance agent before buying one. Another option would be to buy a wood furnace which is a wood stove that sits outside your building and the heated air is blown to your building via an under ground duct. However, I would insulate your shop before doing anything else otherwise, you are just burning dollars and contributing to global climate change.

-- Art

View patcollins's profile

patcollins

1420 posts in 2326 days


#10 posted 01-22-2016 12:15 AM

Have you thought about something like this, it warms what it is pointed at but not the air.

http://www.amazon.com/Optimus-H-4438-14-Inch-Energy-Saving-Oscillating/dp/B001F5ST84

View JerryLH's profile

JerryLH

104 posts in 772 days


#11 posted 01-22-2016 12:28 AM

I took a furniture making class in Pennsylvania (I’m from Oklahoma) and the school’s owner used a wood stove and always has. Many people working at one time, lots of dust – no explosion. The school is – JD Lohr School of Woodworking. I’m sure he would be glad to speak with you. http://www.jdlohrschoolofwoodworking.com/

-- Develop your character -- for it becomes your destiny. Jerry - Mannford, Ok

View RogerM's profile

RogerM

759 posts in 1860 days


#12 posted 01-22-2016 12:36 AM

I have an extensive insulated shop and have used a wood stove (LOPI) for over ten years with no fire or combustion issues whatsoever. Love a wood stove in the shop and would do it again if I were building another shop.

-- Roger M, Aiken, SC

View shipwright's profile

shipwright

7165 posts in 2259 days


#13 posted 01-22-2016 12:37 AM

I have used wood stoves in my various shops for about twenty-five years and think they are a great solution to all sorts of problems…. Cold shop, buildup of scrap wood, and yes, a great place to burn your sawdust and chips. I regularly add a half shovelful or so of sawdust, even fine floor sweepings into the burning fire with no ill effects. If there is a lot of fine dust in it and you are too vigorous in your tossing, you may get a little very localized “woof” at the door of the stove but that is the extent of the “explosion”.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees. http://thecanadianschooloffrenchmarquetry.com/

View bbasiaga's profile

bbasiaga

754 posts in 1456 days


#14 posted 01-22-2016 01:43 AM

In order for dust to flash, it has to be small, dry enough, and create a dense enough cloud. Basically, the cloud must be thick enough that you can’t see your hand at the end of your arm. This, of course, can happen in an area the size of a dime, which explodes and lifts more dust, which then also explodes…etc.

So any source of heat or spark that is in close proximity to dust is a risk. How much of a risk? That depends on how old and how dry your dust is. A clean shop is a safe shop. Fresh dust that hasn’t had a chance to dry is less of a risk than old dust that sat there and dried out. A wood stove is less of a risk because it doesn’t circulate the air. However, if dust is allowed to settle on it and get bone dry, then a cool breeze and a static discharge at the wrong time could be a problem.

I spent several years engineering dust explosion prevention systems. I wouldn’t call myself and expert, but I would say I am pretty well informed. A lot of wood working businesses that have had dust problems have them in the ventilation system, where dust collects, dries, and static builds up. Fires (vs. dust explosions) happen when sparks or slag is sucked up into the dust collection or ventilation system. Don’t do metal work in your wood shop.

I can’t say your home shop is not an explosion risk. But I would say, as mentioned above, your jet heater is a way bigger risk for carbon monoxide poisoning than dust explosion. Switch to something that doesn’t have an open flame, or is vented outside like your furnace.

-Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

View conifur's profile

conifur

955 posts in 612 days


#15 posted 01-22-2016 02:29 AM

I worked for 20 years in a coal fired Power Plant, we pulverized the coal finer then talcum powder, it gets blown into the boiler section, it flash burns in there, we never had an incident at any of the 5 PP that are utility ran. I was at a safety demonstration at a old PP that was going to be destroyed/razed, they did a coal dust explosion in the facility, cameras ect, fuel air monitors, ect, for the air to fuel mix to achieve it the air had to be almost impossible to see through before they could get it to the right mix to flash explode, and they had propane torches burning as igniters.
THATS WHAT I SAID!!!!!!!!!!!
In order for dust to flash, it has to be small, dry enough, and create a dense enough cloud. Basically, the cloud must be thick enough that you can’t see your hand at the end of your arm. This, of course, can happen in an area the size of a dime, which explodes and lifts more dust, which then also explodes…etc.

So any source of heat or spark that is in close proximity to dust is a risk. How much of a risk? That depends on how old and how dry your dust is. A clean shop is a safe shop. Fresh dust that hasn’t had a chance to dry is less of a risk than old dust that sat there and dried out. A wood stove is less of a risk because it doesn’t circulate the air. However, if dust is allowed to settle on it and get bone dry, then a cool breeze and a static discharge at the wrong time could be a problem.

I spent several years engineering dust explosion prevention systems. I wouldn’t call myself and expert, but I would say I am pretty well informed. A lot of wood working businesses that have had dust problems have them in the ventilation system, where dust collects, dries, and static builds up. Fires (vs. dust explosions) happen when sparks or slag is sucked up into the dust collection or ventilation system. Don’t do metal work in your wood shop.

I can’t say your home shop is not an explosion risk. But I would say, as mentioned above, your jet heater is a way bigger risk for carbon monoxide poisoning than dust explosion. Switch to something that doesn’t have an open flame, or is vented outside like your furnace.

-Brian

-- Knowledge and experience equals Wisdom, Michael Frankowski

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