Static electricity issue with PP and PE fuel tanks.

[tabletop]

In researching materials to construct a fuel tank for an off road motorcycle I've been made aware that standard PP and PE have too high a surface resistance and therefore store static electricity. Very special grades are available (tho not in small volume) with resistances of half or less than standard resistance and are considered safe for use in explosive environments.
To the best of my knowlege however even new bike tanks are being made still with standard materials. Is this allowable because the tank is 'earthed' and always at the same potential as the rest of the bike and therefore not considered a hazard?
Thanks.

 

[MikeHalloran]

Are off road motorcycles required to meet _any_ standards?



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

The complete tank does not need to be earthed, just the part that contacts the nozzle of the fuel can or the bowser.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[unclesyd]

Standards or not, and even if some people do make tanks from non-conductive materials I wouldn't do it. I've seen some nasty accidents from similar applications.

http://list.uvm.edu/cgi-bin/wa?A2=SAFETY;xRpMsA;20051031092814-0500E

 

[unclesyd]

patprimmer,
The incidents that I referred to were a person started to fill several 5 gal PE containers with gas and as he got to the third one there was poof with a nice fire. He never had the nozzle in the container as it sparked as the hose nozzle approached the container opening. The dispensing nozzle was grounded.

Another one was where a person had put a larger plastic gas tank on his portable generator and as he reached over the neck of the tank to retrieve the cap there was spark to his arm with a resulting flash from the fumes emitting from the tank which also ignited some spilled gas.

I don't know how one would ground the neck of plastic container without have a metal insert nozzle.

 

[patprimmer]

The car I had for quite a few years had a metal plate at the top of the filler neck it served to restrict the size for unleaded petrol and to earth the nozzle contact area. As the filler neck plate was attached to the body, it was automatically grounded. Ford made a few hundred thousand of these in Aus and I never heard of one burning due to static when filling. Some did burn due to a common fuel leak from the throttle body injection directly onto the distributor cap, but none from static at the tank.

A plastic jerry can is a different story as it must be earthed to ground.

A motor cycle tank would also need a specific ground strap from the filler cap opening to ground.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules