Why we are asked to switch off our mobile phones in petrol bunk?

Question

Can anyone tell me the scientific fact behind it?

Answer 1

Electricity makes sparks-

Answer 2

Its mostly bunk.

A. There have never been any incidents where a cell phone has directly caused an explosion or fire at a gas station. Cell phones have been linked to some gas station fires and explosions and have often initially been credited as the main culprit but further investigation has shown that it has been another cause which I will explain below.

B. For about 10 years now all cell phone batteries are protected against overload in the event of a short. Either through the use of a resetable fuse (PTC) or standard fuse. They will not explode or heat up significantly to cause ignition. Switching is done via transistors, so there is no spark to speak of

C. While the cell phone does produce EM radiation its very low and will not have sufficent energy to cause a spark on a metallic surface like you would see if you through a roll of tin foil in a microwave.

The real culprit in gas station incidents involving cell phones is static electricity. I have seen a few videos captured on gas station surveilance where a person will leave the nozzle in the car to go get their ringing phone in the car. Entering and leaving the car will often generate static, so when the person leaves the car to touch the nozzle again, a spark will occur igniting the fumes from the gas tank or the nozzle.

Edit: Sorry Magece this just isnt the case. Yes petrol fumes are already in a gaseous state so there isnt an effective flash point - any spark in concentrations above the LEL and below the UEL will result in an explosion, but a cell phone does not generate a significantly powerful EM field that would result in sparks on a metal surface or on metal particulates.

If you are referring to Autoignition. It happens at a very high temperature. I think its in the 250degC range for petrol fumes, but it is certainly not anywhere near 75degC (where plastic devices would become unbearable to hold for a prolonged duration.)

I have personally tested this myself in many hazardous locations (Natural gas, pertol fumes and oxygen rich environs) , but you don't take my word for it. Mythbusters covered this myth twice and busted it twice.

Answer 3

Apparently, there have been cases of fires starting from petrol fumes when a mobile phone is dropped (something to do with the battery dislodging and sparking at the contacts). Highly unlikely, but so is a fire being started by a cigarette when filling the tank, and smoking at the filling station has been banned for decades.

Answer 4

There is a chance of fire accident if you activate your cellphone in a petrolbunk. As petrol is highly inflamable and a little spark is sufficient to ignite the petrol.

It is also advised to switch off the two wheelers when you load it in the petrol bunk with petrol, as there is a chance of petrol overflowing and falling on the hot engine, which may catch fire and lead to accidents.

Answer 5

Because if you have a cheap phone, it is possible for a spark to fly that would ignite petrol fumes, which could cause an explosion.

http://urbanlegends.about.com/library/weekly/aa062399.htm

It has never actually HAPPENED, mind you, but it's theoretically possible, even if the chance is infinitesimally small.

What is far more likely is that reaching into your pocket to grab your cell phone could generate a slight static charge, which could cause a spark, which could ignite gas fumes. And even the chances of that happening are very, very slim.

Answer 6

Because the electromagnetic emissions could possibly find an antenna to heat, causing ignition of the flammable fumes.

Most cell phones are not independently rated as "Intrinsically Safe" for explosive environments. There could be an arc from the battery that causes ignition of flammables, or the signal could cause a spark . . . Too many possibilities for catastrophic failure.

Answer 7

It's probably not necessary but in case a cell phone were to produce a spark or get real hot it could ignite petrol fumes. So, it's just a safety precaution.

Answer 8

The likely reason for this precaution is possibly because of the high-frequency waves, which may interfere with any other electric equipment in the vicinity and may cause a spark.

Answer 9

There is NO scientific fact behind this.
A UK tv show Top Gear actually tested this.
Several different phones were tested and none of them made any sparks.

Total Urban Legend.

Answer 10

Static electricity could create sparks.