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Can Cell Phones Ignite Gasoline Vapors?
Iphtashu Fitz writes "Matthew Erhorn was filling his car with gasoline outside of New Paltz, NY when when he flipped open his cell phone to answer a call. The next thing he knew he was engulfed by a ball of fire. Luckily for Erhorn a quick thinking employee hit the emergency fire suppression system and he ended up with only minor burns. Firefighters investigating the accident concluded that the cell phone triggered the fire. Experts at The Petroluum Equipment Institute disagree however, attributing the fire to static electricity. Since 1992 the PEI has documented 158 cases of gas pump fires believed to have been started by static electricity. Apparently cell phone signals are too weak to ignite gasoline vapors, but the human body can generate enough static electiricy (60,000 volts) from simply sliding out of your car seat to do just that. Do you pay attention to all those signs at the gas pump telling you to to make sure your car, cell phone, PDA, pacemaker, etc. are all turned off before you start pumping?"
The warnings about not using your cellphone at a gas station is because you might drop it and the battery pack might come loose. This could spark as well and cause a not-so-static discharge.
Moving on from the gas station thing, what are people's policies about cellphones (or mobiles as we call them in the UK!) and computers. I'm currently in my computer science lab and if I get my phone out of my pocket I'll be banned for the day.
Are they being overly paranoid? Can cellphones really disrupt your average PC in as much as they might ignite petrol fumes...
In Finland, the local subsidiary of Esso has forbidden tbe use of mobile phones at gas stations. That has been effect for a few years. No-one seems to follow the rule, however. :)
hapo
for your cell phone to ignite a fire from gas fumes.
But it's the pizo-electric buzzer that would cause it. Most cell phones have a pizo-electric transducer that generates the ring tones. Pizo electric devices can generate high voltage discharges, in fact they are used in ignitors for gas grills. But this would only happen if your phone rang while you were pumping gas, not if you were to make an outgoing call. The transmitter in your phone CAN'T cause a fire.
The commutator sparks would be the most likely couse IMO.
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FWIW, for over a year now it has been illegal to even have your cellphone on at gas stations in Puerto Rico. If you are seen using one at a station you can be fined (forget the exact penalty, but I think its like $250). We were somewhat baffled when this law went into place, and it still seems there is little fact to support it.
Not to pick on women, but I did hear that it was mostly women who would cause fires by static electricity. This was because they would most often leave their purse in the car or have want to attend to the kid inside of the car once they've started pumping the gas.
The recommendation was to get out of the car and stay out until you're done filling the tank.
Another tidbit: If you're filling up a portable gas tank, it is recommended that you maintain contact between the gas nozzle and the can during the gas transfer. This, due to the gradual transfer of electrical charge as the gasoline flows from the hose into the gas can. Keeping nozzle in contact allows the charege differential to equalize continually without turning your gas can into a capacitor...zap!
Hey, it's the gasoline that causes the burns not the cellphone. :-)
We are blaming the wrong item here
Time to get rid of this way to old fashioned source of energy anyway.
if your pants fit well, it's not only because of the pants
They did manage to get a very nice explosion by leading a wire to the cravan and getting soomeone wearing nylon clothes and standing on a bucket to touch the other end, though.
PS. They really liked blowing up caravans...
It seems as if, reading the report, that nearly all of these accidents resulted from someone putting the nozzle into the vehicle, then locking it on, leaving, coming back, and a static discharge igniting the vapours near the filler cap.
This is reasonable - you quite often feel small static shocks. Especially in dry hot weather, perhaps explaining a high incidence of acccidents in Texas and Nebraska, and a lot less in humid coastal ares.
And when you are filling up, you often see clouds of vapour almost pouring out of the filler. These would be very easy to ignite.
Here in the UK you can't put a pump on automatic fill. You need to hold the trigger whilst all the time. The handle is grounded, so that as soon as you touch it, the static goes, and as long as you keep on holding it, there won't be a problem, as there will be no sparks.
I have a video on my email, girl gets out of car, starts pumping her gas, gets back in her car to what looks like put some lip stuff on. she gets back out and goes to touch the handle pumping gas into her car, and whooosh! fireball.
she pulls the nozzle out of the car, and you can see fire comming from the gas tank, as well as the nozzle. she ends up dropping it and running away.
all from a little static..
On the Discovery Channel there is a show called Mythbusters (love that show) and they tried every which way to see how a cell phone can ignite gasoline vapors.
They had there "blast chamber" filled with gas vapors and oxygen. Called the cell phone and nothing happened. Infact they ended up trying just static electricity and still nothing happened.
Getting in and out of your car is much more likely to cause a spark, precisely due to static electricity. Especially in dry climate and cold days (when people are more likely to leave their engines running as well as get back in the varmth of their car during fueling). And yes, it has been shown that women are more likely to get back in their car during fueling.
Quidquid latine dictum sit, altum sonatur.
I work for a major manufacturer of gasoline dispensers (and many run Linux).
The sigificant risk for ignition via a cell phone is by dropping the phone. The battery separates, and a spark insues.
UL defines the Class I Division 1 area (considered explosive) as approximately 3 feet high and 18 feet in diameter from the source (dispenser). At the typical operational height of a cell phone there is little risk, even if there was sufficient RF energy. However if you drop it, the vapor does hover above the ground and presents a significant risk.
The predominate risk is static electricity. In times past (the 90's and earlier), vehicles would simply vent the vapor (largely pentane and butane) from the tank's fillneck by displacement as fuel was introduced. This led to a cloud of saturated vapor in proximity to the fillneck that was too rich to ignite at the fillneck interface. Newer vehicles have onboard vapor recovery whereby a carbon canister retains the vapor as your dispense. Consequently saturated vapor no longer clouds the fillneck area and the explosive region moves closer to the fillneck where a spark from static dischage (nozzle to car/hand to nozzle/hand to car) will cause ignition.
Treat fueling like handling a chip. Discharge yourself against the pump chasis first (damn well grounded) and vechile to put everything at the same potential before dispensing.
NEVER refuel a portable gasoline container upon an insulated surface like a carpeted trunk or plastic truck bedliner. Set it on the concrete, otherwise you've crated a perfect Lynden Jar capacitor. Many fires happen in this manner.
...every time I get out of our mini-van (shut up) I get the crap shocked out of me when I touch the door. I always make sure I touch it before gassing up.
I thing the biggest danger (besides the morons who smoke at the pump) are people who fill plastic gas cans in the back of pick up trucks. I've seen a few videos of people doing that going up in flames.
One time there was a guy filling his tire right next to the pump with one of those 12v mini air compressors, while filling his gas tank. I asked him if he knew how dangerous that was. He didn't understand until I pointed out that the compressor has an electric motor in it.
666-607: 6th floor apartment of the beast
put the stuff in a closed environment, tested many concentrations of gas vapour, nothing worked.
,no... typically RV's that are burning at gas stations are usually because the old fart forgot to extinguish the pilot lights on the fridge and water heater and to shut them off...
The only way this happens is static electicity near the fuel entrance
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nothing like a RV water heater deciding to ignite to heat water to help along a gasoline fire...
Now granted these usually only happen because the same old feeble guy yanked the gas hose out of the tank fill hole while still spraying gasoline around getting gasoline under the RV so vapors could collect and be ignited by the pilots...
I know I saw 2 of them the last summer.. both were really old farts and they were not making very good decisions, or had horrible hand-eye coordination and couldn't figure out to let go of the pump handle to stop the flow of gas.
the scariest part? these old guys are DRIVING these house sized vehicles...
Do not look at laser with remaining good eye.
You're not going to get high voltage out of a piezo transducer which is being driven from a 4.5 volt battery through a low-impedance path. And if you could get high voltage by dropping it, lots of people would have blown electronics from dropping their phones; you might notice that this does not happen.
Time is Nature's way of keeping everything from happening at once... the bitch.
The stats also show that women are "the cause" of more fires at the gas pump. Hey, don't blame me... it's just the stats, ma'am!
Nylon rubbing against cotton in a dry environment is a midget lightning storm, quite suitable for igniting gasoline vapor (or any other explosive vapor mixture). Women wear full-leg nylon stockings or pantyhose under loose cotton dresses MUCH more often than men. B-)
[...] Mythbusters [...] episode #2: [...]Can chatting on a cell phone while pumping gas cause the pump to blow up?
First you need an explosive mixture. With gasoline that's a rather strong concentration in air - present in a narrow region JUST OUTSIDE the gas pipe when filling without a vapor revovery system.
The you need a spark IN the explosive mixture. The spark can be VERY tiny. But it must be surrounded by the correct mixture, with a trail of the mixture back to the cloud of vapor emerging from the filler neck, through an open path large enough to propagate the flame without stealing its heat and quenching it (as passage through a metal screen with suficiently narrow holes will do).
Such sparks can occur on the breaking (and sometimes making) of any electrical contact inside the phone. But phones are pretty well sealed - especially the flexible circuit contacts under the buttons. (I'd be more concerned with the switch detecting the cover of a flip-phone.) You'd probably need a phone with a defect in the case - as well as holding the phone near the filler neck while filling for several seconds - to ignite gas fumes that way.
Another potential is arcing at the tip of the antenna (where the voltage is enormous) or the tip of a nearby object like a sheet-metal screw. (Even a near-invisible brush discharge would do the job.) Such screw tips are normally not found in the region around the filler neck where an explosive mixture is likely (both because they'd tend to savage the hands and clothing of people trying to fill the tank AND because they encourage static discharges, so the designers very carefully keep them away from the filler.) The tip of the antenna on a cellphone is normally imbedded in rubber, so no arc there unless there's a defect (like a pinhole) in the rubber. Also: Except for the old AMPS-system phones the cellphone signal is a rather broad spread-spectrum. This reduces its ability to excite a resonance in nearby metal leading to a high-voltage at the end of a conductor (like a screw point).
Note, however, that a cellphone doesn't have to be switched by the user to transmit. It sends a short burst every few minutes when it "checks in" with the local cell sites. An incoming call turns its transmitter on, increasing the opportunities to get any arcs it's producing into the explosive region as the user moves it around.
Third: If the battery came off you'll get a spark at its terminals as it disconnects. Again the caveat about getting an explosive mixture to the area of the spark with a path back to the vapor cloud.
Jamie and Adam "testing several explosive theories" on one segment of a show are hardly an exhaustive disproof. How many of the hundredish models of phone did they test? Did they arrange for a controlled concentration of gasoline at the phone, neither too rich or too lean, so it would actually ignite? Did they crack the phone cases in various ways to create an ignition path? Did they carefully make a pinhole in the rubber duckie antenna right at the end of the conductor?
Just like being hit by lightning or meteorites, gnition of vapors during fueling, from ANY source (even lit cigarettes!), is a rare event that nevertheless occurs when the conditions are JUST right. And getting the conditions right is hard - in part because automobile designers try to reduce its likelyhood. Millions of fillups occur daily, yet ignition is very rare. No offense to Jamie and Adam, but a few attempts to get it to occur while taping one segment of a show would be extremely unlikely to result in a fireball, e
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Actually, you can start a fire with the end of a cigar/cigarrete. The difference is vapors. A large gas spill on a non-porous surface causes a vapor build up near the ground very rapidly. The cigar enters the vapor field and ignites before it hits the main pool of liquid. If the vapors weren't present the cigar would just drop into the pool and go out, just like in your experiment.
People keep coming up with this whole "Cell Phones are dangerous in gas stations" stuff. Well, if you're going to ban cell phones due to the risks, then you really ought to consider the bigger risks, I'm sure there is a far greater risk from doing something as stupid as bringing a combustion-engine powered vehicle into a gas station!
perl -e 'print "Just another Perl newbie\n";'
Actually, I've heard this is a myth too - the guy a few posts up has the reason: The airlines don't let you use phones in flight becuase they were ASKED not to by the cell phone companies. If the planes on 9/11 were flying at their normal crusing speeds, cell phone calls would have been impossible, and those supposed calls to family members would not have taken place (they could have been AirPhone calls though, and the media, families, etc., just got the details wrong, which would be understandable under the circumstances).