You have to differentiate between temperature and quantity of heat. These discharges have more than adequate temperature to ignite vapors present within the substance's flammable limits. It does not have a sufficient quantity of heat energy to cause solid objects to pyrolosize and ignite.Originally Posted by chrneaNope no heat. The heat is only created by current which is the movement of electrons from an area of high concentration to an area of lower concentration. Static electricity is just that. Static, Not moving, therefore no heat. The heat is generated only when there is a path for the electrons to flow.
Ok, quick science review folks. Current is the product of the voltage divided by the resistance or
I (current)= V(volts)/R(resistance). Understanding that the resistance encountered in a normal static electric charge is in the hundreds of mega ohms. (million ohms) I=40,000volts / 5Mohms which equals 8 milliamps. Not enough amperage to cause heat that you can feel and maybe enough to cause you heart problems if said current was passed through the heart. (don't panic static charges dont go through you, it is just on your skin) hence all you usually feel it on your skin.
I thought my first post of the ad with the 500,000 volt van de graf generator would have ended this notion. I am not any good at posting pics but I know most adults have seen these things. They are the metal balls that you put your hands on and your hair raises and all that cool stuff. It produces little lightning bolts that jump from the machine to your hand as you get near the machine. This is perfectly harmless at 500000 volts. Why would anyone think that 40,000 volts would be harmful? Its not the voltage but the current that causes the fires. The current in these static discharges is to miniscule to generate heat to cause ignition of clothing or carpeting. Now Gas vapors are a completely different situation. It takes next to nothing to ignite fuel vapors which is precisely the danger in these fuel pump accidents. Getting in and out of your vehicle causes friction and causes a buildup of a static charge. This potential is constantly looking to go to a more neutral state. As you get out of your car wearing rubber or leather soles (insulation from ground) and you grab hold of the nozzel that has insulating rubber on it and pull it out of the tank. At this point some electrons have started to travel from you to the car, but when the nozzle clears the car the flow stops and the voltage hunts for the next path of least resistance. It can find that through the vapors. Then you get a quick discharge of electricity through the vapors in the form of a spark and boom ignition.
Now the setup for this has to be perfect. It is extremely difficult to reproduce even in a lab but it can and does happen. Cellphones and radios give off electromagnetic pulses as it were that can cause the buildup of electrons on a person. And now you can get the cycle all over again. It takes very precise circumstances to make this happen which is why you probably couldn't reproduce it. But it doesn't make the danger any less real.
The safest way to pump gas is to shut off the car/truck completely. Remove even the key. Pump the gas and remain outside the vehicle at all times. If you can't stay out of the car, then make sure that you ground yourself at all times. Remove the nozzle with one hand and place the other hand on the car. This keeps you grounded and reduces the chance for a spark. Put the cell phone down and the radio as well. (unless you are sure that they are intrinically safe)
Be smart, stay safe, and don't get burned.
Ps this is a non issue for the most part with diesels. The fuel vaprs from diesel have nowhere near as low of a flash point as Gasoline.
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09-21-2005, 04:23 PM #21
Originally Posted by chrnea
- Join Date
- Jul 1999
- Flanders, NJ
09-22-2005, 10:15 AM #22
The whole deal with the gas pump is you dont discharge static electricity you might buildup sitting in your car . You can sit in your car if its cold out while your filling up but when you get out of the vehicle have both feet placed on the ground and touch the vehicle to discharge you electric charge away fromt he fuel vapors.
I've watched about 5 videos on idiots going inside theyre car then coming out and touching the gas handle and whooosh omg my cars on fire." We are not extraordinary people , we are people caught in extraordinary situations. " Chapter 1 IFSTA Manual
09-25-2005, 07:07 AM #23
- Join Date
- Jul 1999
- Flanders, NJ
What happened to all of you who were going to check this out? Were you able to verify the fact that the Chief had no idea what he was talking about?
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