Shielding / Grounding of OH Oil & Gas Pipe Lines

[EPEngineer]

Hi,
Is there any international (European, American or British)standard which describe the method of providing lightning protection for overhead oil and gas pipe lines? I have come across 800 meter long pipelines laid on 17meter height overhead pipe racks (reinforced concrete structure) carrying gases (which may catch fire only if mixed with oxygen) within an oil and gas plant area. I would like to determine whether any lightning protection will be required for these pipe lines? as these are metal pipes, will it be practical and adequate if we ground these pipelines at regular intervals?. Are there any specific requirements to be followed while grounding the oil and gas pipelines?

Regards

 

[sslobodan]

Well Those pipes should have standings(pillars) that are obviously standing on ground. That is the path where circuit will close in case of lightning strike. Considering pipes are above touching range and have no electrical parts there is no chance to damage anything due to a lightning, considering that there is a few millimeters thick galvanized pipe and by that corrosive protected. The only issue can be made if pipes are not from galvanized material and can get rusty and start leaking gas. So other than standing pillars no other equipment you have should have grounding. The pillars on which pipes are standing should be connected with Fe/Zn stripe 20x4 or 40x4mm that is usual for grounding installations so you can exclude possibility that someone touched the pillar in a moment of lightning and got killed. Also if pipes have no metallic connection to the pillar grounding it should be done at places where there is possibility of human touch (closing valves measuring substations). In other cases no one will allow you to do anything with those pipes because it would cause a leaking of gas and dangerous situation. Lightning will always close over minimum resistance (to ground) circuit, bear that in mind.

 

[alehman]

The U.S. National Fire Protection Association standard #780 on lightning protection does not require the use of air terminals for protection of metal objects with greater than 3/16 inch (4.76 mm) thickness provided they are properly grounded. This is a general rule for structure protection, not specific to gas pipelines however.