Headings Electrostatic
Charge Search Questions 
Dangers.
When charge jumps across
an air gap it
causes a spark.
The spark can ignite (set fire to)
flammable liquid
vapours
and powders in pipes.
Care must be taken to avoid sparks when putting fuel in cars or
aircraft.
The fuel itself is an insulator (a hydrocarbon)
and charge can be transferred as it flows through a pipe
if the pipe is also an insulator.
This happens because there is friction between the fuel and the pipe.
As the nozzle (the end) of the pipe is
brought close to the fuel tank,
a spark can jump between the two igniting the fuel.
This can cause a serious
explosion,
particularly with aircraft which are
filled at very
high speed.
The spark can be avoided
if the pipe nozzle
is made to conduct by connecting an
earthing strap to it
and so any charge can be safely
conducted away.
An earthing strap connects the pipe to the ground
(the Earth).
In addition, a cable can connect the pipe to
the fuel tank,
so that there can be no difference in
charge between them.
There is a very similar situation with powders in pipes.
If the powder is an insulator
then charge is transferred in the same
way as fuel in pipes.
A spark can ignite a powder and
cause an explosion
just like a flammable liquid vapour.
The solution is the same.
Use earthing straps between the pipe and earth.
Headings Electrostatic
Charge Search Questions
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