Explosion caused by OFF power tool?

[socaldmax]

Originally Posted by LakeSuperior

I have never picked up a static charge from a vehicle even in super low humidity weather.

A wire to ground on the fuel nozzle doesn't help the receiving end of the nozzle prevent a charge transfer through air.

Perhaps the carbon in the rubber bleeds static charge to ground.
Additionally, cars would explode regularly if they picked up static charge.

Still not buying the pickup bed static charge mechanism.

It's not necessarily the pickup bed that causes the static charge, it's the fact that the vehicle is insulated from ground by the tires.

There are plenty of examples of people getting a static charge from their clothing and the discharge starting a fire.

This lady's sweater caused the static build up:

https://www.youtube.com/watch?v=tuZxFL9cGkI

Another guy climbed back in and out of his car:

https://www.youtube.com/watch?v=b89x8CAS6xU

Here's a guy who was filling gas cans in the bed of his truck:

https://www.youtube.com/watch?v=8wiUBCMdO7Y

Another truck bed gas can fire:

https://www.youtube.com/watch?v=1tYO4jvnJHw

[a64pilot]

Supposedly the problem with the PU beds is in the plastic insert, I don't know if it builds static or is an insulator, but there is no risk of refueling cans in the bed of a PU that does not have the plastic bedliner. I think the spray in ones are not an issue.

If your really interested in this subject

http://www.esdjournal.com/static/refuelfr.htm

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[Wotname]

A couple of facts:

Car tyres are conductive, they are made that way.
The concrete surface at a filling station is conductive, it is made that way.
The filling hose on the pump is conductive, it is made that way.

However, there is no control of what type of clothing people wear or their shoes or the material of car seat covers. The static build up we notice when exiting a car is due in the main by the interaction of our clothing and the car seat covers. Most of this build up is discharged when we exit the car by either touching the metal exterior of the car or when we first touch the pump. However if we get back into the car, a new static build up can occur and this why one should never re-enter the car during refuelling.

[Wotname]

If you want to understand these issues, research ESD and its control / prevention in electronics.

[hellosailor]

If you re-enter a car while refueling:
1-You're not controlling the pump. It might slip out, especially if you're heavy or the car rocks as you open/close the door.
2-You're not controlling the pump, you might not notice when it sticks & overflows. They've been known to do that. Or, to leak out of a rusty fill pipe.
3-when you open or close the door...these days? All sorts of circuits go on and off. The dome light turns on, the door ajar buzzer comes on, the power control computer (in many new cars) turns on and starts to monitor circuits...all sorts of circuits are energized. Each giving a chance of a spark, including the solenoid lock on some gas filler cap doors. (OOooops.)


Actually, if grade school kids were given a tour of the local burn ward, they'd probably have nightmares for a decade but they'd sure respect fire more. Anyone with extensive burns is put into a medically induced coma, because even a fatal dose of morphine isn't strong enough to stop the pain if they are conscious.


There may be worse ways to die, like being drawn and quartered or disemboweled. But there aren't many accidents that put you in those situations. Fire, OTOH, is pretty much always lurking over your shoulder.

[brownoarsman]

Thanks for an informative thread. I now know why I pay for plastic gas cans that always seemed to me to be just oddly shaped milk gallons!


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[mcarling]

Lots of comments about safe and unsafe practices regarding fueling. No mention of safe and unsafe practices regarding power tools. I was taught as a child to never, ever leave any power tool plugged in while not in use. Aboard, I keep all circuit breakers switched off by default; only those which need to be on are on at any given time.

[Ribbit]

Originally Posted by alansmith

The gaseous vapors, which were much heavier than air, crept along the counter top over 20 feet away and hit a lit Bunsen burner. Ba-boom...It was quite exciting.

Similar almost went KaBoom when my Chemist uncle was working away making tablets in the lab at the back of the Chemist shop (what Americans call a Drug Store) he was working at.

Luckily out of the corner of his eye he caught sight of a fascinating serpent like flame, slowly working its way through the air. Then he thought it might be a good idea to look where it may be headed.

His eyes lit on a very big glass storage jar of ether.

If there was a World Record for sprinting across a lab and grabbing a big jar of ether and heading outside with it, I think he'd have broken it.

[socaldmax]

Originally Posted by a64pilot

Supposedly the problem with the PU beds is in the plastic insert, I don't know if it builds static or is an insulator, but there is no risk of refueling cans in the bed of a PU that does not have the plastic bedliner. I think the spray in ones are not an issue.

If your really interested in this subject

ESD Journal - Auto Refueling Fires

Sent from my iPad Pro using Cruisers Sailing Forum

Yes, there can be a static buildup on the truck or person either from clothing or in really dry conditions, just from driving. I've been driving through the sand dunes and gotten a shock every couple of minutes or when I touched the frame or gear shift knob.

It's much less common in humid areas, but since the deck of a boat or a dock isn't conductive, it could be possible the transfer of gas could build up a charge that eventually arced over to something else (like a grounded power tool) because the deck or dock wouldn't dissipate the charge. Or there might have been some other nearby ignition source.

I've seen gas vapors travel a long way, twice it caught everyone off guard when the flame ran under someone's feet and they realized they were inside of a ring of fire. In one instance it was the father lighting a large campfire and his son was standing behind him engulfed in a fireball. The father spun around with the gas can in his hand and in the process sprayed gas all over, which also burst into flames. All the closest people jumped up and rolled the kid on the ground and all he ended up with was scorched tennis shoes.

I remember the father telling us, "Thank God my son is OK! There's no way I could go home and tell my wife I burned up the kid, there's nowhere on this planet I would have been safe from her!!"

[Delancey]

Originally Posted by MarkJ

Yesterday's fire that destroyed 3 boats has an interesting bit of unsubstantiated gossip that I wanted to get your thoughts. http://www.cruisersforum.com/forums/...in-160162.html


Hypothetical scenario: a person is decanting petrol/gasoline so the fluid is going through air. Next to the person is a power tool, say a cutter or drill, which is off, but plugged in.
Could the fuel vapor enter the tool and close the switch contacts making a spark causing an explosion??

.

Sent from a stupid phone that replaces words with weird stuff.

Maybe this?

[MarkJ]

Originally Posted by Delancey

Maybe this?

Oh, yeah, didn't think of that.



Mark

[HappyMdRSailor]

Originally Posted by a64pilot

Flowing fuel by itself can develop static, reason why trucks are bottom loaded, and if they are top loaded, there is a long dip tube to provide a constant ground, but that is usually only in areas of extremely low humidity that it's a problem.

INDEED!

Last time I transferred fuel, there was a tiny scrap of paper dancing all over the 1/2" PE line... I took some video of it... Will find and post...

Originally Posted by Muckle Flugga

This is interesting and didn't know that. So poured fuel in a low humidity environment could theoretically be self igniting?

Originally Posted by a64pilot

Yes absolutely I was looking for the film I saw years ago of static bolts being discharged in a big fuel tank being filled. Reason it didn't blow we were told was the mixture was too rich, not enough air in the tank.
US Army burned a fuel depot at Ft Irwin when I was there top loading a fuel truck without the dip tube.


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Originally Posted by kimden5

I was filling an old military style steel 5 gal. jerry can in the back of my pick-up truck which had a factory installed plastic bed liner and when I went to take the fuel nozzle out, it must have created a spark as the can caught fire. I was able to get the flaming nozzle away from the can at which point it went out and then had the presence of mind to put the lid on the can. Quick thinking for an old man. I was lucky.

I puckered a little bit there kimden...

Originally Posted by skipmac

There are conductive plastic drums used in the chemical industry for flammable materials but they are quite expensive and used only for very high purity solvents that are otherwise compatible with PP. I doubt the fuel jugs we buy are made of the conductive grade.

When filling drums with flammables regulations (and common sense) require the drum be grounded during the operation. This is a very real concern.

PS
I feel the same about getting SCUBA tanks filled. Usually like to walk around to the other side of the shop.

And really fat tires...

[HappyMdRSailor]

Originally Posted by sartorst

My grand father who worked at a gas plant told us several story's in which a worker would have to strip down naked to prevent static and run into the plant to close a valve to stop a leak. Safety standards were different in the 50s-60s

Originally Posted by socaldmax

That's as good a reason as any to hire a hot secretary.

Could possibly be why "privates grooming" wasn't so popular back then... Seems like a telltale "canary" situation...

[HappyMdRSailor]

Originally Posted by Delancey

Maybe this?

Originally Posted by MarkJ

Oh, yeah, didn't think of that.

Mark

I think Delancy has got it Mark... How many times have you heard your cord end buzzing when you plugged in... ? Too many times for me too !

[rwidman]

Originally Posted by mcarling

Lots of comments about safe and unsafe practices regarding fueling. No mention of safe and unsafe practices regarding power tools. I was taught as a child to never, ever leave any power tool plugged in while not in use. Aboard, I keep all circuit breakers switched off by default; only those which need to be on are on at any given time.

Do you do that at home as well?

I worked in a shop where the stationary power tools were hard wired. No unplugging them. At home my stationary power tools are left plugged in (unless I'm changing blades). Portable tools may or may not be left plugged in although more and more of them are battery powered. I don't remove the batteries except to charge them (or change blades).

Circuit breakers in my home and on my boat are left on unless I turn them off for a reason. I think most folks do pretty much the same as me.

I think the thought behind unplugging power tools is so children can't accidently turn them on. I have no children in my home.