Oil/Gas In rubber hose - Static implications

[jbond]

Hi Guys, I'm an electrical engineer
Posting this in here, but if it's not the right forum, please point me to another

Issue is, that I'm involved in doing the grounding design at a type of fuel station where trucks (tankers) will be filled with a fuel

I think that the equipotential leads that earth the truck/tanker when its filling have a switch on them so that you can (I guess) control when or not the truck/tanker is floating and when it's grounded

Does anyone have any info on the purpose of that switch or can you shed some light onto the usefulness of it?

Also, if the fuel is diesel, which I believe is combustible but not flammable, then is there any need to worry about static discharge?

Cheers!

 

[dcasto]

when loading trucks of any kind of material,its not that the truck is grounded, its that the truck is bonded to the equipment it is loading from. This means there is not POTENTIAL charge between the truck and the tanks/pumps et al.

I've seen trucks loading saltwater with some heavy oil and vapours burst into flames because the truck was not bonded to the tanks they were pulling from.

Guess what, diesel is falamble under the right conditions. Diesel makes a good fire starter for bond fires and in backyard barbies too.

 

[Longinthetooth]

All the loading/unloading stations I have seen constructed recently have some form of interlock so that loading/unloading cannot commence until the truck is correctly bonded. As an electrical, I guess you know how to do this better than I can.

 

[Unotec]

We have to connect to ground all trucks prior to load/unload, otherwise the pumps will not start (interlocked).
In our case, all equipment is grounded, therefore the trucks have to be grounded.
In other applications, as dcasto indicated, the truck/tanker has to be bonded to the equipment.
In both cases the goal is the same, cero potential charge.
I am not going to say either is fail safe, because I have seen truckers that "ground" their truck by the front fender while they are unloading from the back. There is no guarantee that there is conectivity throughout the truck.
If you google on why gas stations require you not to get back into your car while loading you'll see what I mean.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[jbond]

Yeah, thanks for the help guys.

I found out that the purpose of the switch was so that the initiation of contact (that could result in a spark) would be geographically (located) away from the hazardous area.

That is, if there wasn't a switch in the equipotential lead, then you could spark AT the truck when connecting it up. Better to be doing the spark at a safe distance (the location of the switch).

Cheers

 

[JLSeagull]

Check API RP 2003 and NFPA 30 for grounding, bonding, interlocks and static relaxation. Also review the signals and interlocks at existing bulk plants or product terminals similar to your project.