Grounding vs potential difference vs dispensing fuel

[5689]

I work for the canadian goverment at the direction of fisheries and ocean. We are dispensing fuel to vehicule, boats, ships, helicopter form different type of storage facility such as drums, mobile tanks and fixed tanks.

I'm at writing the procedures for fuel dispensing and I'm looking for references for the grounding part of the dispensing.

My understanding is that before dispensing we need to ensure that there is no potential difference (voltage) between the drum and the helicopter. This is achieve by connecting with a wire the drum to the helicopter. Is there a real need to be connected to the ground with another wire and a ground rod?

That is the opinion of another engineer out here but not sure of that?

Also when refuelling a ship form a mobile tank what I see to me is the same case of the drum and helicopter, I only need to connect together the mobile tank and the ship. Does I need to be connected to real ground?

thanks for your advices.

 

[BigInch]

When tank vehicles are unloaded into aboveground storage that may or may not be adequately grounded (e. g., airplane fueling), the truck is first grounded, then bonded to the receiving storage and then the nozzle is bonded before refueling begins. There are special precautions taken with the refueling of airplanes from tank vehicles since both have been subject to static accumulation due to the air and tire movement described above. For example, the US Air Force has discontinued the use of alligator clamps and now uses jack assemblies.

Generally, tank cars are sufficiently well grounded through the rails, and bonding of the tank car is not necessary for protection against static generation. However, there is the possibility of stray currents (see Part II, Lightning and Stray Currents), and the loading lines should be bonded with the rails to assure a permanent bond.

Marine vessel loading and unloading does not require bonding cables between the vessel and the shore. This is unique since the hull of the vessel is inherently grounded by virtue of its contact with water. Thus, accumulation of static charges on the hull is prevented. Instead, an effort is made to electrically separate the loading and unloading lines from the shore piping by inserting an insulating flange between the vessel piping manifold and the shore piping manifold. This would not apply to filling onboard tanks not electrically connected to the hull.

There is product movement during filling that can develop a static charge between the liquid surface and tank shell, or metallic fittings, in a non-metallic tank. To minimize the risk: avoid splash filling, limit the velocity of the incoming stream, avoid ungrounded objects in the tank (e. g., gauge floats), don’t introduce entrained air with product flow, and allow a minimum relaxation time of 30 minutes for the charge to bleed off before opening.

And a few other docs I have collected on static electricity are attached.



**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[5689]

thanks a lot biginch,

Is there something you dont know about petroleum facility? Would like to have you on our team!

thanks again

Pierre

 

[BigInch]

Merci beaucoup






**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[5689]

do you speak french?

 

[JLSeagull]

The last that I read, BigInch was hanging out in Spain.

 

[BigInch]

I would really want to learn to speak it. I read French, Portugese and Italian reasonably well, but speak only EN and SP. I do understand Scottish, which I feel is my most outstanding accomplishment in languages.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[JLSeagull]

Understanding Scotts is pretty good but how about the Jordies (Newcastle)?

 

[BigInch]

Actually I was learning Cajun there for awhile.

Remember him?

Warning sound bytes follow!
Set the audio level appropriately for your listening environment.

http://www.justinwilson.com/audio/cemetery.mp3

Pierre, sorry for the digression. Hope you found it entertaining.




**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[dcasto]

bonding is the key, not grounding. A helicopter can fly a person up to a 100,000 volt line and bond (equalize the potential between them) and a person can then touch the line. neither the helicopter nor the power line is grounded.

I've seen an explosion where an grounded tank and a grounded truck were connected, put no bond was made between them. the small insulating effect that was different between the two was enough potential that there was an arc and boom.