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Franklin Sankar 07-14-2020 06:45 PM

Studio fire
Anyone came across any data on electric studio fires. Which is more common, electric or gas?
What is the most common cause?

Pete VanderLaan 07-14-2020 06:53 PM

Bad Housekeeping to put it bluntly. Keep your unsupervised tooling at least 18 inches from combustibles. More preferably. Get combustibles away from the active part of the shop.

Art Freas 07-14-2020 07:07 PM

No data to back this up but. I have gas for furnace and glory holes, electric for annealers. With gas I worry less about fire more about explosion. With electric it is fire. As an ex-firefighter I agree with Pete, bad housekeeping is a huge factor, followed by stupidity, and then bad construction/electric/gas practices. Keep a clean shop, don't be stupid, and build stuff right and you can rest way easier in a hot shop or anywhere else. Dumbest thing I saw as a firefighter was a house where they took an extension cord, cut it in half spliced in about 20 feet of speaker wire using telephone connectors and routed it under a pile of laundry in a linen closet. Biggest surprise is that it took a month to start a fire.

Pete VanderLaan 07-15-2020 07:38 AM

I made a point of studying studio fires for several decades as a sidebar to my time in the fire dept actually and pyrolysis was primary again and again. It takes about 20 years to develop at low levels. At high levels, it can happen fast. What you have to remember is that materials don't burn but the gas given off by them warming does.

In the major instances I saw, furnaces, all gas sat in the same places for that period of time. One had a large wooden beam behind it in a mill and one had a beam supporting a concrete slab underneath it, also in a mill. In both cases the wood was not actually directly exposed but was capable of absorbing heat and the furnaces ran just about continuously. Both beams gassed off and ignited once sufficient gas was produced. Both fires were very substantial in the damage they created. Housekeeping in both cases would have limited the damage. It did get me to reconsider the ambient temperatures I considered "Safe" It used to be that I thought 165F was OK, not anymore. Now, 135F is where my attention focuses. Look to lightbulbs near wood. If you see blackened material, your building is talking to you.

If you're just trying to light a fire in a fireplace you have to wonder sometimes how I ever had a job. It can be a major pain to get it lit. The question there is the rate at which the BTU's are generated and what they are trying to kindle. Inevitably, you want the fast release stuff like newspaper to catch some small pieces of a slightly slower rate of release material and then let it light something else, blah blah blah. Stuff like Georgia fatwood releases gas so fast that you can often ignite it with just a match. That should tell you something about where you store your fatwood, or newspapers or birch bark, all great gas producers.

So in the studio, limit the stuff that can catch. I've had two studio fires in fifty years and the first one, in Santa Fe caught some material under the hood where we had been making color rod. The hood was utterly devoid of combustibles and the fire put itself out. The other, I don't know what to say might have happened. I did something foolish as I look back. I had taken the leads from the electric panel and ran them through the hood to get them to the moly control. I insulate my hoods. Both of the lines were in heavy metal conduit and about seven years passed with no issue. Then, one morning I was standing in front of the thing and a major electrical short presented itself in the hood. It did not trip a breaker since the breaker was a 125 AMPs. The arc burned right through the armor and down into the underside of the hood at which point I threw the breaker and the event ended. I do not know what might have gone on had I not been there.

Analyzing it, I pulled the leads from the hood and the insulation on them was completely cracked and falling off from years above the furnace in the heat. Finally, It arced to the armor. In any other application that would have blown the breaker but since the power supply to the moly was really big, it didn't. In repair, feeling like an idiot, I ran the lines a second time but this time over the top of the hood.
Insulation cracks for more than just this reason. Exposure to sunlight will do it as well, chemicals can do it. It's worth examining your tools. When I talk to people about doing maintenance on large electrical furnaces like molys, I tell them to check their connections at least every two months for "cold creep" and that includes the connections in the transformer. Keep them snug. I did have an incident in my transformer where, again the insulation had frayed leading out from the relay to the secondary. It melted an aluminum lug in the transformer and I was fortunate that the metal did not go down in the windings or I would have been coughing up close to three grand for a new transformer.

Pete VanderLaan 07-15-2020 07:40 AM


Originally Posted by Art Freas (Post 148231)
Dumbest thing I saw as a firefighter was a house where they took an extension cord, cut it in half spliced in about 20 feet of speaker wire using telephone connectors and routed it under a pile of laundry in a linen closet. Biggest surprise is that it took a month to start a fire.

At one time I was quoted in the newspaper saying

"I haven't been to a fire caused by common sense yet."

Steven O'Day 07-15-2020 03:10 PM

I just replaced a rubber hose to a 20# propane tank. It was about 4 years old but had been outside. It seemed to be ok until it was flexed and then you could hear the gas escaping along multiple cracks.

Pete VanderLaan 07-15-2020 04:43 PM

I do not know the cause and origin on Harry Bissett's fire in Vermont two years back. We just never got to talk.

Art Freas 07-15-2020 06:10 PM


Originally Posted by Pete VanderLaan (Post 148235)
At one time I was quoted in the newspaper saying

"I haven't been to a fire caused by common sense yet."

Awesome, great quote!

Franklin Sankar 07-15-2020 09:32 PM

Great story Pete. How often do you all change the propane hose?
I would think gas fires are more common. Surprised to hear itís electric.
What caused the electric. What you think about the controller output sticking. If it overheat , the coil melt and open so no electricity flows

Pete VanderLaan 07-16-2020 07:28 AM

gas fires are still the most common cause. Electrical fires can almost all be avoided with simple monthly maintenance. When the moly was initially introduced the thought was that this was a low maintenance tool. It is anything but that. I did not include two studio fires for molys, both at the transformer. One was a stadelman, one was from Halem's offering. It does seem tp be the case that when relays stick, they always stick in the closed position and can cause runaways. That's why an upper limit controller is always a good idea, just more expensive. It's necessary with Electric, not so much on gas.

Inspect your propane hoses, it's as simple as that. Keep a clean shop, unlike me.

bob gent 07-16-2020 08:32 PM

my studio fire
I had a studio in a very old industrial building back in the late 80s, and we put the furnaces in little rooms that were lined with transite (yes, the asbestos board) It all went pretty well until a friend of mine who wanted to learn to blow glass came in to practice at the end of my shift. it went as predicted with him dropping a piece off the punty. No biggie, it fell behind the scrap barrel so he picked it up and tossed it in. I shut things down and went home only to get a call a few hours later that the place was on fire. The fire department came up with their own explanation, but it became clear to me that the wood inside that wall, which there was covered with steel, had been rotting for decades. All that soft punky wood was leaking out the bottom of the wall where the steel was rusted through. When my friend picked up his dropped piece, neither of us thought to see if it had caught anything on fire. going home immediately sealed the deal. He probably feels guilty to this day, though I never told him that was probably what started the fire. It was my responsibility to check, and I didn't. He wound up helping me build my next studio, and we both enjoyed lots of time making stuff in there, just a little more safely

Franklin Sankar 07-17-2020 05:49 AM

I have some plastic buckets of water placed around the studio. Hope it melts and spill the water. Lol.
Pete is your high limit controller ,a controller with a high limit alarm?

Pete VanderLaan 07-17-2020 08:16 AM

I sold mine with the electrical panel for the moly. I really don't need one on the gas unit. I do recall that Watlow made it.

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