Summary

Very little risk by smoking near an airplane fueling

except if there happens to be a wind to vaporize the fuel so be sure and hold a balloon with you while boarding to check for a wind

Since this thread has gone well off topic, allow me to continue....I would be interested in any comments on this...

I was among the passengers bussed out to a KQ E190 at Addis Ababa recently. On arrival at the aircraft, boarding was done with passengers being allowed onto the a/c in groups of max 5 people "because the a/c was being refuelled".

I have never encountered that before, what is the logic? Is that a KQ thing? An Addis airport thing? An ICAO thing ?

Surely not ?

Lomapaseo,

Taking your remark as somewhat T.I.C., this forum does have a habit of being becoming a de facto reference source. No smoking/Naked lights airside is a pretty universal sanction, certainly in Western Europe and the U.S., for good reason - mitigating risk is why aviation is as safe as it is.
Cannot commend the decisive action taken by the captain enough

Fair enough, it's just that I haven't seen many becalmed days while boarding at airports

Since nobody has answered this I'll venture a guess that, since it was airstair and not jetway loading, they didn't want a big line of people at the airplane waiting to slowly get in the door while they are fueling.

From a chemistry point of view, yes you could extinguish a naked flame with kerosene, it's got a pretty low vapour pressure and a reasonably high flashpoint.

I wouldn't recommend it though especially if it is atomized.

Point is, fuel in liquid form won't burn. Only the vapour burns.
A full fuel tank contains little vapour, but an empty fuel tank is full of it.

But all you need is some vapour

You then need to take into account the probability of an ignition source and the probability of sloshing to fill a larger closed area

An empty tank is full of vapour. When you fill the tank this displaces the vapour which overflows, (heavier than air), falls to the ground to make a puddle of vapour. This could very well be an ignition hazard especially on a calm day.

A couple of observations.

(1) The old Paddy Ashdown joke. He was in a meeting in his HQ in Bosnia, which was next door to a petrol station. His staff were getting all worked up about this being a dangerous location - what if the baddies were to blow up the petrol station?

"Have any of you lot actually tried to blow up a petrol station?" asked Paddy.

"No", they said.

"Well," said Paddy, "I have, and it's bloody difficult."

(2) Marquess of Bristol. Smoking whilst refuelling his chopper at Cambridge. Then took off straight from the pumps, none of this taxying to where ATC told him to or any of that nonsense.

Very wrong! By that logic it would be safe to weld a drained petrol tank where there is no atomised fuel spray.
Obviously, to burn, any form of any fuel also needs oxygen mixed with it....if that's what you're getting at?

P.S. do NOT try welding a petrol tank at home, or anywhere else.

Btw, years ago I saw a fire begin in an almost full motorbike petrol tank. Once the (thankfully small) volume of fuel/air vapour above the liquid fuel in the tank instantly burned with a "pop" the fire blew itself out. Thankfully, the person nearest put the fuel cap back on again.

The video posted is a YouTube video that contains many technical errors and the guy clearly does not fully understand what he is talking about (plus anyone who stands over a jar full of petrol and throws a match into it is clearly lacking in brain cells!). The fact is that vapour most definitely does burn! the term "flammable liquid" is technically a misnomer as it not the liquid that burns but the vapour that it gives off when combined in the right proportions with oxygen in the atmosphere. All flammable liquids have a property known as the flash point which is the temperature above which it will give off sufficient vapour for it to ignite if a source of ignition is present. In the case of volatile fuels such as avgas or mogas that temperature is around -45 deg C so they give off flammable vapour at all normal temperatures. JetA1 has a flash point of at least 38 deg C so needs to be heated above that temperature before it will give off sufficient vapour to ignite.

......... and gasoline has a flash point around -40 deg C. Yes, that's MINUS 40.

Hmm - Do you mean -40deg C or deg F ?
Both the same at -40

Darwin would have something to say on the matter.