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Joined: Oct 2000
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What are the recommended procedures for grounding and bonding fiberglass piping in chemical atmospheres?
Are there any available documents, or publications that can be used by operator's?
Joe Tedesco, NEC Consultant
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Joined: Mar 2001
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Joe,
Are you referring to minimizing static electricity?
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Joined: Oct 2000
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Redsy:
Yes, that's one the reasons for this question.
The facility uses various highly flammable fluids, such as acetone, methanol, and ethanol.
Joe Tedesco, NEC Consultant
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Joined: Nov 2000
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Joe,
I don't understand how nonconductive piping can be bonded or grounded?
Don
Don(resqcapt19)
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Don,
In an explosive atmosphere you MUST bond your plastics because of the static, you create one VERY big problem if you don't
Joe, I always had to rely on the manufactures info for this. There is so little in the code, and even IEEE documents that you had to rely on the UL ratings and user guides.
NFPA 77 can be very instructive in this case as well.
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Geroge,
I know that sometimes a metallic path is provided to discharge static along a nonmetallic transfer system, but I don't consider that bonding or grounding of the nonconductive piping system. You can not make an effective grounding or bonding connection to a nonconductive object.
Don
Don(resqcapt19)
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Wouldn't the static buildup inside the piping, where the fluid flow is??? So wouldn't it follow that some type of wire inside the piping, possibly bonded to the core of the pipe. I've seen and installed lots of fiberglass piping. Never seen a static strap except on plastic(HDPE) piping that connected to a brass fitting at a termination
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I found a position paper from the "Fiberglass Pipe Institute" that verifies the hazards and supports some of the positive comments made here. Nonmetallic fiberglass pipe and fittings are available with a grounding wire entrained in the resin and meets MIL-P-29206A for jet fuels and petroleum liquids.
Joe Tedesco, NEC Consultant
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Joined: Nov 2000
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Joe,
That makes a lot more sense. Now we are bonding or grounding a conductive object, not just a nonconductive pipe. There is some information in the IEEE Green Book that says a bonding/grounding path with a resistance of up to 1,000,000 ohms is sufficient to prevent the build up of static charges.
Don
Don(resqcapt19)
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Don,
There are many instances where a simple piece of PVC can harbor sufficient static to create an explosive atmosphere, especially along the inside wall of the pipe.
In these cases, you can also ty-wrap a simple piece of #12 alongside the outer edge to dissipate your charge. As long as it is continuous, the ohmic value can be as great as 1 meg with no harm to the value of the ground.
What !!! never made a rubber battery?
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