Getting petrol - turn engine off or not?

[Thorin]

Can't you put a cigarette out in a bucket of petrol? Not enough energy in it to ignite the fuel or something. I seem to recall reading something like that anyway, but it's certainly a bit over the top asking people to turn mobile phones off.

[Class One]

I have seen someone smoking in a garage, and trying to fill her car. Some bloke came out and told her to put it out, I just stood there stunned, I could'nt belive someone was that stupid or ignorant:) not sure which

 

Both

[MrRalphMan]

Can't you put a cigarette out in a bucket of petrol? Not enough energy in it to ignite the fuel or something. I seem to recall reading something like that anyway, but it's certainly a bit over the top asking people to turn mobile phones off.

 

Pretty sure that is correct as it's the petrol vapor that goes bang...

[Soop Dogg]

It's not the fuel itself that's the problem, it's the fumes given off to air while refueling.

 

 

Have you ever put fuel in your car on a sunny day and looked at your own shadow on the ground? You can see the fuel vapour coming out of the filler neck and and tumbling down the side of the car to the ground - it's way heavier than air.

 

Although I do think it'd take more than a hot exhaust to ignite it, a filling station forecourt is not the place to try being a mythbuster!

 

I turn the engine off.

[kieren1234]

 

Have you ever put fuel in your car on a sunny day and looked at your own shadow on the ground? You can see the fuel vapour coming out of the filler neck and and tumbling down the side of the car to the ground - it's way heavier than air.

 

Although I do think it'd take more than a hot exhaust to ignite it, a filling station forecourt is not the place to try being a mythbuster!

 

I turn the engine off.

 

 

I actually saw it on the program "myth-busters" about the mobile phone and there is no way it can ignite the fuel and is 100% safe to have the phone and be speaking on it whilst filling up. But you cant be too carfeull so...........

[MrRalphMan]

Apparently it's all the ladies fault, well 65%.

 

http://www.bbc.co.uk/dna/h2g2/A20701540

 

[garethr]

Petrol vapour is dangerous stuff.

 

Someone I know lit a fag while transporting a petrol container inside his car..... very nasty. He won't do that again. For one thing I don't think he has enough fingers to operate a cigarette lighter one-handed.

[Ian C]

Some old mobile phones can interfere with the remote radio pump cutoff, so if there was a problem/accident, the operator couldn't shut the pump down.

[Guest Chumpalot]

I always switch the car off when filling up.

[BASHTHEBISHOP]

I found this an odd question....

 

Is it not illegal to exit your car & leave it running?

 

A negligible risk of detonation but a risk all the same?

 

Do people in the forecourts not shout at you over the tannoy etc?

 

Why not smoke a large cigar, talk on your mobile phone and wear a suit made of fuse wire:p

[Branners]

still havent seen an answer as to why its dangerous to leave the engine running. Yes there are fumes, but what would ignite those fumes if you leave the car running?

 

JB

[neil tt]

What happens if it miss fires a nice little fire ball blows out the exhaust:d

[Gaz Walker]

What happens if it miss fires a nice little fire ball blows out the exhaust:d

 

What happens if you accidently hit the 2-step rev limiter?

 

Gaz.

[Marco]

I don't leave my car behind with the engine running. I turn it off when I go inside to pay. They've never asked me to turn it off either.

 

I've spoken to a guy who worked in petrol station for over 30 years and he said it wasn't a problem to leave it running. The chance of the petrol catching fire is very slim

 

On new cars it could mess up the petrol indicator on the dash though (apparantly)

[Matt Harwood]

I fail to see why its dangerous to leave the engine running though. You arent going to be waving the fuel filler around enough to get fuel on to the engine, the exhaust system will still be almost as hot as it was when you first pulled up and fuel generally needs a spark to ignite it and not just heat.

 

Can somebody explain what the problem actually is, what could ignite the fuel while the engine is running?

 

I always turn off the engine but it would be good to know what the danger is in case I need to leave it running for any reason.

 

JB

 

Having worked in a petrol station many moons ago, I think I can answer that one.

Basically, it's older cars that can cause the issue. Cars that use HT leads in their ignition system carry very high voltages through the leads whilst the engine is running. If the HT leads are old, or start to break down, they can cause sparks to fly about in the engine bay. (If anyone used to muck about with old cars years ago, you may remember seeing the fireworks displays they make if you lift the bonnet at night in a dark area).

It's not the fuel itself that ignites, it's the fuel vapour. If the vapour were to ignite and make its way to the underground tanks, you wouldn't live to see the results. However, there are many precautions in place to prevent explosions, and switching the engine off is just one of them, and to be honest, the chances of ignition through dodgy HT leads is unlikely.

 

Mobile phones aren't a fire hazard as such. They're supposed to be switched off for the same reason that phones aren't allowed in hospitals and airplanes. They can interfere with the computers and electrics at both the pumps and the main control unit.

[Mike M]

I can see why why mobile phones are not allowed to be on in the presence of petrol fumes as they are non Ex rated. For an electrical device to be operated in a hazardous atmosphere it must have a suitable safety rating so in the event of equipment failure any energy released whether it be heat or a spark will not be sufficient enough to ignite any hazardous atmosphere present.

 

As for turning the engine off i can only think the same as Neil TT says. Back firing exhaust. Mean you they let you in with a sticking brake with a bright orange disc, well I think if they noticed they wouldnt LOL, but they dont have warning signs for that.

[renegade]

i've filled up once with the engine running but that was because the battery was knacked had to be jump started .not what you want to be doing in a petrol station ,one wrong spark

 

but i wouldn't do it again as i try to keep to the rules:innocent: in the petrol station

[snake]

why would you want to temp fate leaving the engine running.

your car is easy to steal door open engine running etc.

would you feel at ease if a biker left his engine running when

filling up if you were sat waiting with small kids in the back.

anyone who smokes in a petrol station must be brain dead.

[Branners]

so its safe to say that you are at more risk due to another car pulling in next to you with dodgy HT leads than you are with your own car nowadays?

 

Theres probably a greater risk from the Miami Vice reject with cleats on his shoes kicking up a spark than there is from a car. So leaving the engine running isnt really dangerous in itself, its the mess that the thief causes when he runs you over that you need worry about.

 

JB

[snake]

:chav:he looks like this

[mattanna]

There is a theoretical risk that as there is so much vapour around it can be drawn in to he vehicle intake system, i.e through the radiator grill etc etc, and there is a spark etc, the fact is you do not know if you have a spark or a particularly hot element etc, I think the main reason is hot exhaust gas exiting, your exhaust is usually quite near to where you are filling up and the vapour; exhausts are known to send out small sparks plus whilst running exhaust gas is being forcefully pushed out some distance, when off the exhaust remains hot but is not pumping it(or a spark, hot bit of debris) out etc;now blowing yourself and your own car up is one thing, but if she blows on the forecourt it will be a mighty blast.Interestingly when you restart your engine though you may cause more of a spark but you are not filling and vapour around your vehicle should have dissipated.Fuel depots only have diesel vehicles to eliminate sparks, however they think the buncefield depot blew from a spark from a lorry exhaust. I know of a tractor that shot a spark from it's exhaust and set fire to the huge load of straw it was carrying.

[DJButler]

There is a theoretical risk that as there is so much vapour around it can be drawn in to he vehicle intake system, i.e through the radiator grill etc etc, and there is a spark etc, the fact is you do not know if you have a spark or a particularly hot element etc, I think the main reason is hot exhaust gas exiting, your exhaust is usually quite near to where you are filling up and the vapour; exhausts are known to send out small sparks plus whilst running exhaust gas is being forcefully pushed out some distance, when off the exhaust remains hot but is not pumping it(or a spark, hot bit of debris) out etc;now blowing yourself and your own car up is one thing, but if she blows on the forecourt it will be a mighty blast.Interestingly when you restart your engine though you may cause more of a spark but you are not filling and vapour around your vehicle should have dissipated.Fuel depots only have diesel vehicles to eliminate sparks, however they think the buncefield depot blew from a spark from a lorry exhaust. I know of a tractor that shot a spark from it's exhaust and set fire to the huge load of straw it was carrying.

 

 

Of course we all realise that the most sparks are produced by the com and brushes in the starter motor sitting down there by the heavier than air fumes dont we, Hmmmm maybe the experts missed that, all academic really, the sign says NO so why bother discussing it at great length, keeps us awake waiting for the explosion i guess!!.

[mattanna]

Of course we all realise that the most sparks are produced by the com and brushes in the starter motor sitting down there by the heavier than air fumes dont we, Hmmmm maybe the experts missed that, all academic really, the sign says NO so why bother discussing it at great length, keeps us awake waiting for the explosion i guess!!.

 

But there should not be a large amount of petrol vapour around the starter motor unless you have a bad leak, the amount of vapour coming off when fuelling is excessive, you can see it.

[Soop Dogg]

Like everything else, at least part of this is down to insurance. If they don't have the signs up and endeavour to make the customer comply with the warning, they will invalidate their insurance.