Gassing up - turn engine off or not ???
 

OK, my wife and I are originally from Chicago and we have been in TX for about 1.5 years now. We have of course established quite a few local friends. When gassing up, we are used to leaving the engine running, usually to keep either the heater or A/C going. Well ever since we moved down here, without fail if we have one of our friends in the car, they will reach over and take it upon themselves to turn the ignition off (!@#%$*&). For some reason they get all freaked out if we have the engine running! They think we will all end up in a fiery inferno or something.

First of all, is this a regional thing? I noticed a lot of people down here turn their engine off while pumping gas, despite frequent 100 degree days (their kids meanwhile are roasting in the back seat).

I understand the thinking that somehow a fire might start (especially with all the "turn engine off" propaganda signs posted everywhere). But come on, unless you're driving a 308 or a 911, there is just no way the fumes are going to maintain strong enough concentration to reach all the way up to the front of the car where the engine is running. And even if it does, you would have to have a whole lot of arcing or sparking going on in order to cause ignition. And vapor alone doesn't burn as easily as atomized fuel. So what gives? Am I just wrong? Am I unknowingly taunting the reaper?

Has anyone else thought of this or looked into it?

The biggest threat is low humidity combined with a static electricity discharge. So much humidity in many areas, particularly in summer, that it is probably not a real problem. However in areas of very low humidity, getting back in the car after starting the gasoline to stay warm, and then getting back out to finish can start a static discharge fire. Have seen videos of this, and it can be almost like an explosion. Leaving a gasser on during refulling can be against the law, but is likely no more risky than the above scenario. Diesels, on the other hand, can injest a vapor cloud and blow clear to the moon, as the air is already in the combustion chamber and HOT.

You're taking a chance of incinerating yourself and bystanders.

http://hypertextbook.com/facts/2003/ShaniChristopher.shtml

Bot

Ignition Temperature. Taftan Data. 1998.
"Each fuel should be brought above its Ignition Temperature for starting the combustion process. An appropriate air-fuel ratio is also necessary. The minimum ignition temperature at atmospheric pressure for some substances are: carbon 400 C, gasoline 260 C, hydrogen 580 C, carbon monoxide 610 C, methane 630 C."

Ignition temperature is the minimum temperature at which a material will burn or explode. It is the temperature at which a mixture of flammable vapor and air would ignite without a spark or flame. The term ignition temperature is also used to describe the temperature of a hot surface that would cause flammable vapors to ignite. Gasoline is the most common flammable liquid and the main cause of injuries among teenage boys. The ignition temperature of gasoline ranges from 530 and 553*K.

There is no direct correlation between explosive properties and ignition temperature. Therefore, materials can have the same physical properties and similar explosive properties while having ignition temperatures that vary greatly. The ignition temperature is affected by the chemical properties of the flammable liquid. When a flammable liquid is in its liquid state, it will not ignite. It will only burn when in its gaseous state.

In addition to ignition temperature, other properties associated with the flammability of a liquid are its flash point, flammable range, and vapor density. The flash point is the temperature at which a flammable liquid vaporizes and is therefore able to ignite. Liquids with a flash point under 40*°C are considered combustible liquids. Gasoline has a flash point of about -45*°C. The flammable range of a liquid is the ratio of the flammable liquid to air that would create a volatile mixture. The flammability range of gasoline is between 1.4 and 7.6%. If the ratio of gasoline to air is less than 1.4%, then the mixture is to thin to burn. The mixture cannot burn when it contains more than 7.6% gasoline because it is too rich to burn.The vapor density is the weight of a vapor relative to the weight of air. The vapor density of gasoline is heavier than air and therefore will sink when in air.

Check out my thread "Will you please shut off your engine Sir" over on the diesel discussion. A station owner asked that I shut off my diesel while fueling. You'll find a wide variety of opinions on that thread, and we were just talking of diesels.

I wouldn't thin diesel would be a problem except in enclosed spaces. It's vapor pressure is too high, isn't it?

I'd like to read this thread but I can't find it... can you post a link? Thanks!

Man if you leave your engine running around here and someone notices you get a nasty ticket I believe its $500.

Oops, looks like the thread was lost in the great October crash of 05.

It is illegal in the state of Texas to leave a vehicle idling. It's a safety issue, and the chances of a spark generated fire from gasoline vapors is a much more realistic chance than most think.

Theres always a chance of a backfire and/or a leaky exhaust system igniting fumes. Combine that with some goofy fuel filler locations (remember the ones down low behind the license plate on GM cars?), hence the law. Even if it were legal, its wasting gas.

It probably qualifies as a risk as much as swimming after eating. Of course the other big threat in our lives is using an electronic device or cell phone on a plane, however the $5/minute phone in the seat is perfectly safe. Go figure.

Way back in the early 80's, I was gassing up at a local station. The guy on the other side was also gassing up but had his engine running. I mentioned to him that it was illegal 'by order of the fire marshal', there was a sign posted for everyone to see. He mad some snappy remark along the lines of 'Are you a fireman?' and just at that point, the nozzle shut off, and fuel gushed out, all over his hot muffler. His car didn't catch on fire but the look on his face was priceless.

Pumping gas while the engine is running
 

I nominated you for the Darwins Award for 2005.

Risk TOO high!
 

gmercoleza,

'forget the engine(s),Gasoline or Diesel...The threat is the Generator/Alternator
OR......this will keep you awake at night, the Starter.

You pull into your favorite dispensor of fossil fuels and leave the engine running.

NO automotive or truck manufacturer equips their products with SEALED/
SHEILDED Alternators/Generators or Starters!

We are cautioned against leaving the Cell/Sat phone on when refueling, in
case of an incoming call (Non-shielded ignition source).

Ditto with the engine running ,the electrical regeneration source for the
battery is nothing but SPARKS!

In the second scenario, there is a fuel leak with the corespondent vapor
emissions... and you engage your starter (Non-shielded ignition source).