Substation1

This sign is a common sight in Petrol / gasoline refilling station.

Caution
Do not use mobile phone while filling your car.

There is a danger of explosion when using the mobile phone while filling your car with fuel. Is this true or just a myth?

This is just a myth. The mobile phone got no sufficient power to radiate radio frequency which may cause a nearby conducting medium to act as an aerial.

Any conducting object can act as an aerial and collect energy from any radio frequency radiation field. This energy is then released as a spark or arc by failure of insulation.

The recognition of this problem came to fore in the early 1980s after incidents in Europe. This resulted into the production of a British Standard 6656, first issued in 1986 and extensively revised in 1991.

As per BS 6656, a transmitter need to transmit more than 2watts average over any 20us period to be able to ignite combustible hydrocarbon gases. The current digital mobile phone does not have that power. If during the early days of the mobile phone where the transmitting power ranges from 5 - 10 watts, then the possibility of ignition is high.

References:

  1. BS 6656 (1986) The Prevention of Inadvertent Ignition of Flammable Atmospheres by Radio Frequency Radiation
  2. Electrical Installations in Hazardous Areas - Allan McMillan, ISBN 0 7506 3768 4, Reed Educational and Professional Publishing Ltd 1998