resistance value on pipeworks and Static Earth on plastic pipe

[shkim2000]

I'm designing electric parts on FPSO. The metallic pipework is bonded for resistance measurement maximum 10 ohm. Anybody know 10 ohm is too low or any other value.
Against static earthing for plastic pipework how should I control ? I have no idea how to control static electricity plastic pipe.

 

[alehman]

What is FPSO? Static dissipative PVC pipe is available. What is the application? Why is static a concern?

 

[butlen]

(FSPO Floating Pumping Storage Offloading Vessel?)

In order to prevent electrostatic charges, a typical leakage resistance of 10^6 ohm should not be exceeded for any part of the system.

Polyethylene or PVCU will produce a static charge, but both can be manufactured (specially) with additives to allow conductivity.

It is most important to carefully ground any conducting wetted components as any charge will be stored there.

Is the plastic pipe likely to see a flammable mixture inside or outside - flammable gas/air or vapour/air mixture? If the vapour or gas will not have air entrained
inside then any charge will not have a flammable mixture to ignite.

 

[mc5w]

I would put an 8 inch long section of metal pipe into any plastic pipe that is 8 inches in diameter or less. For larger sizes of plastic pipe use a longer section of metal pipe.

In a book titled Old Electrical Wiring the author David Eli Shapiro found an instance where a tingle voltage was coming up through the slime inside of a plastic drain pipe for a shower. He was never able to find the source. My experience is that deteriorating underground electrical wiring can leak quite a bit of electricity into the soil even during a drought. The current flow then energizes drain pipes and concrete slabs. This is how you can get shocked by properly grounded appliances and water pipes.

Interception of tingle voltages will be more demanding than any kind of static electricity concern. Your bonding conductors should be minimum of #4 solid copper or #2 stranded copper for pipes that cannot serve as a grounding electrode. Sizes for pipes that can serve as a grounding electrode will depend on your service capacity.