fuel tank explosion ,question?

Question

4 mythbuster's .can an eletric fuel pump cause the fume's of
an empty jp-5 fuel tank to explode
this has happened twice on same ship no fire involed .can leaving
pump on cause this to happen ?

Answer 1

Yes there have been quite a few instances of this happening in various vehicles, including Airliners.

It tends to be caused by poor wiring, when the tanks are nearly empty, and is difficult to trace after the incident.

Answer 2

I suppose it's possible. For this scenario to occur, you'd have to have three things converge in one time and place:

1) Fuel vapors
2) A source of heat
3) Oxygen

The fuel vapors are already present, and there will be some oxygen in the tank because you've emptied it of liquid (unless you actually draw a vacuum on the tank) I would have to assume, however, that the pump is not a submersible pump, but rather one that is connected via piping or hoses to the storage tank? In this event, the only way for heat to be generated is if the pump impeller were improperly installed and rubbed against the casing, causing friction between the impeller and casing or between the shaft and the motor bearing. Even a short or electrical arc in the motor portion would be isolated from the fuel itself (unless you had a pretty significant leak in the tank), so even then, you wouldn't ignite the fumes.

If, however, you actually use a submersible pump, then this is a much more likely scenario, because an electrical fault in the motor of the pump would actually occur in the same space as the fuel vapors and cause an explosion. The only other thing I can think of is if you don't have a proper connection to ground on the tank; through daily operations, you could build up a significant static charge on a steel tank without a grounding strap, and any sparks or arcing between adjacent metal surfaces could very easily ignite the fumes as well.