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Static electricity & spontaneous combustion

jimtron

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jimtron
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Mar 9, 2005
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Los Angeles, California
This article leaves me scratching my head (not too energetically though, for obvious reasons). This seems implausible, but I'm pretty ignorant when it comes to science (and most stuff).

"We tested his clothes with a static electricity field meter and measured a current of 40,000 volts, which is one step shy of spontaneous combustion, where his clothes would have self-ignited," Barton said.
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I thought spontaneous combustion was a myth. No?
 
Do I spot a bit of hyperbole in that story? :D

We often build up 40,000+ volts of static electricity but there's very little charge stored and therefore very little current can flow. The "click" you get when touching a metal handle, for example, is as bad as it gets.

I suppose it's not impossible for the spark produced to ignite something highly flammable, but "leaving a trail of scorched carpet and molten plastic " - I don't think so.
 
"We tested his clothes with a static electricity field meter and measured a current of 40,000 volts, which is one step shy of spontaneous combustion, where his clothes would have self-ignited," Barton said.
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Anyone who thinks that volts is a measure of current is automatically suspect.

--Terry.
 
When I wear rubber-sloed shoes I can build up a pretty good charge, likely well over 40 KV, when pushing a shopping cart in some stores. EVERY time I've pushed it for a while I get a pretty big spark from my hand to the cooler case, hurts like a good, hard pinch. But so far there's been no smoke or flames.
 
So how did they obtain the number of volts required to cause spontaneous human combustion?
 
The 40,000 volts thing, could be accurate, but the amperage is usually too low to ignite clothing or the like. It could ignite fuel vapors or zap circuit boards, but spontaneous combustion??? Don't think so. Highly unlikely.

We have an electrostatic discharge lab where I work. I could get a pretty quick answer to any specific question you had. I had a demo done for me in that lab once, and was suprised at the high potential charge that existed around a common piece of plexiglas.
 
"We tested his clothes with a static electricity field meter and measured a current of 40,000 volts, which is one step shy of spontaneous combustion, where his clothes would have self-ignited," Barton said.
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"We tested his clothes with a Geiger counter and measured a temperature of 40,0000 milligrams, which is one step shy of homeopathy, where his clothes would have self-potentiated," Barton said.

Same difference.
 
Mr. Skinny said:
The 40,000 volts thing, could be accurate, but the amperage is usually too low to ignite clothing or the like. It could ignite fuel vapors or zap circuit boards, but spontaneous combustion??? Don't think so. Highly unlikely.

We have an electrostatic discharge lab where I work. I could get a pretty quick answer to any specific question you had. I had a demo done for me in that lab once, and was suprised at the high potential charge that existed around a common piece of plexiglas.
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I operate an ESD simulation device (aka Spark gun) at work, and yes, 40 kV is the high end of what can be expected to be generated on a human under certain conditions.

I read it and wondered just WhyTF they would be measureing him before it happened, and how they'd do it in any case? Whay? Did the poor sap have to walk around with some poor schmuck following him with a voltmeter attached?

That whole story just smacks of BS.
 
The original question though was, is spontaneous combustion a myth. I assume its the spontaneous human combustion we are talking about and its not a myth according to my Skeptics guide to the paranormal by Lynne Kelly. The reality isnt so Hollywood though, it takes hours for a person to burn and I cant imagine it happening to a living person.
The myth busters on Discovery have already set things on fire using static electric charges and thats hardly a myth either.
 
Vitnir said:
The original question though was, is spontaneous combustion a myth. I assume its the spontaneous human combustion we are talking about and its not a myth according to my Skeptics guide to the paranormal by Lynne Kelly. The reality isnt so Hollywood though, it takes hours for a person to burn and I cant imagine it happening to a living person.
The myth busters on Discovery have already set things on fire using static electric charges and thats hardly a myth either.
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I think the points being made int his thread are not that SHC doesn't happen or that static cannot start fires, but that:

1) While spontaneous Human Combustion happens, it's not exactly spontaneous. So while it may still be called that, it bears no relation to what the term originally described (except in the aftermath). The real facts of these cases, compared with the myths that people bring to mind when SHC is mentioned, are much different from each other.

2) Yes, electricity (including static) can start fires, especially in highly volatile gases such as gasoline fumes when the electric spark travels trhough them. In people, 40kV is nothing. People are struck by lightning without catching fire (in fact, you're suprisingly likely to survive a lightning strike). While voltage plays a far role, the current (amperage) is a MUCH more important factor (by an exponential amount). The static charge people build up on thier bodies just ain't enough.
 
I like the idea that there's some sort of official human combustion voltage chart that firefighters carry around with them for cases such as these.

Interesting how the man inside the suit managed to avoid doing himself any damage as he wreaked major electromagnetic carnage around him.
 
Originally quoted by somebody
quote:
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"We tested his clothes with a static electricity field meter and measured a current of 40,000 volts, which is one step shy of spontaneous combustion, where his clothes would have self-ignited," Barton said.
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? [/B]
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First, volts are a measure of VOLTage, i.e. EMF.

Current is measured in amps. A "current of 40,000 volts" is beyond meaningless, volts is not a unit of current measure. Amps and its related units are current measures. Volts are not.

All the voltage in the world will not light your clothing on fire, unless there is a very strong voltage GRADIENT, resulting in a CURRENT FLOW, and quite a strong one, to set the average clothing on fire. And getting that much current to flow in dry cloth is going to be, well, interesting. Other things will go wrong first, not the clothing.

ETA: Furthermore, breakdown voltage of air is about 3 million volts/meter.

That means about 30,000 volts per centimeter. If you've ever drawn a spark an inch from a doorknob when in a really dry area on a nylon carpet (and I bet we all have), you've exhibited a field breakdown that would appear to be well in excess of 30,000 volts, more like (depending on the shape of what you touched) 40, 50, or more kilovolts.

I'll go with the guy who says that 40kv is on the high end of ESD voltages. I do think that if you take a 1960's nylon carpet (I lived in such a house when I was a kid) and you shuffle your feet a LOT, you can draw several inches of spark and it really does smart quite a bit, so I think that it is possible to work up more if you try. :)

*ask some of my mom's guests who liked to do things like pinch me on the cheek and all that old lady stuff*
 
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