I'm working on an application in which sparks (specifically from static discharge) present a severe safety hazard. One component in question is a piece of PVC water pipe. It has been proposed to "ground" the pipe to minimize the risk of static shocks between humans and the pipe, and between other components and the pipe. I am skeptical as to whether this component needs to be grounded at all; it's not conductive, so my intuition is that it isn't able to cause a shock. Normally I would just go along with this, however the proposed methods of grounding involve expensive adhesives and coatings which also have a long lead time for ordering.

Can a PVC pipe cause a static discharge? If so, what industry practices are out there to mitigate this phenomena?

The pipe is being used in a test fixture for testing energetic materials, i.e. combustible solids. The energetic material is loaded into a length of the pipe, along with some sensors and other components. The material is ignited, after which the pipe is destroyed. The static spark concern is only during the loading process, when the energetic material could be ignited prematurely. The pipe is not used in its normal manner, like to transfer particles or fluids.

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    $\begingroup$ I know that where particulates are moved through PVC static build up is possible. Depending on your application, some places to start researching might be process piping standards or OSHA's requirements for grounding and bonding when transferring combustible liquids. $\endgroup$ – Ethan48 Jan 19 '16 at 14:07

I am skeptical as to whether this component needs to be grounded at all; it's not conductive, so my intuition is that it isn't able to cause a shock.

My question is basically (1) can a PVC pipe cause a static discharge

Don't confuse conductivity with ability to hold charge. If you've ever rubbed a balloon against your hair to make it statically cling to the balloon, you've witnessed a non-conductive material holding a charge.

This problem is fairly common for woodworkers who set up dust collection in their workshops. PVC piping is often used as a carrier for sawdust back to a central dust collection tank. The (usually) dry sawdust flowing rapidly past the PVC causes charge to build up, similar to a Van de Graaff generator.

(2) if yes, what industry practices are out there to mitigate this phenomena?

The easiest way to ground a PVC pipe is to pull a length of bare copper wire through the entire pipe length (on the inside of the pipe) and connect it to a building ground. This will not ground out the entire pipe since portions of the pipe away from the grounding wire (i.e., on the other side of the pipe cross-section) will be electrically insulated by the PVC itself, but it will mitigate the "danger" of a larger static discharge.

The most effective way to ground a PVC pipe would be to line the inside of the pipe with some sort of wire mesh, but that is both impractical and fairly hard to achieve.

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  • $\begingroup$ Great points. Is there any building code which specifies a method of charge mitigation on PVC pipe? $\endgroup$ – Carl Witthoft Jan 20 '16 at 15:12
  • $\begingroup$ @CarlWitthoft, none that I'm aware of, but I'm not an electrical engineer or electrician. $\endgroup$ – grfrazee Jan 20 '16 at 15:14

As pointed out, non-conductive plastics can build up a charge. In certain applications industry code call for all piping in ex-hazard areas (or where the inside is an ex-hazard area!) to be conductive material, and grounded. To my knowledge,there's no conducting PVC. Hoever both PE and PP can be bought in a coducting variety (they mix carbon into the plastic matrix.

The beaty of PVC ist that the pipes can be glued, with PP or PE you need to weld the pipes or use plug sleeve. I don't know the prices of conductive PP, PE-el is 3-4x as pricey as ordinary PE (and I think with PVC the difference is even bigger).

I would seriously consider using (stainless) steel pipes, maybe with press fittings.

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  • $\begingroup$ This was asked, and answered, in January 2016... $\endgroup$ – Solar Mike Jan 7 '19 at 11:59
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    $\begingroup$ @SolarMike - Answering an older question is perfectly copacetic within the realm of SE if you feel that there is different or better information to provide as an answer. The Q was bumped by a now deleted non-answer, which is what may have caused mart to see the Q and provide this answer. Personally, I wasn't aware that conductive PE or PP existed. $\endgroup$ – user16 Jan 7 '19 at 12:45

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