Coorigated Stainless Steel Tubing To Ground or Not to Gr

[Foorsail]

My question is: Corrugated Stainless Steel Tubing (CSST) a newer product on the marker, which is a gas line used in many places to provide gas with in structures. CSST has been suspect to fires, which are being considered to be and also proven to be, a by-product of lightning strikes (An article written in the October 2005 Fire & Arson Investigator gives more details regarding background to this matter if interested, www.firearson.com)
My question; should CSST be grounded, has there been and ruling regarding this matter? I do understand the manufacture may or may not be recommending / requiring grounding. I am asking for any case study or field-implemented requirements, or pending NEC input on this matter.

Thank you

 

[bphgravity]

Re: Coorigated Stainless Steel Tubing To Ground or Not to Gr

Metal underground gas piping systems are specifically prohibitted by the NEC to be used as a grounding electrode however, 250.104(B) mandates gas piping in or attached to a structure to be bonded to the service equipment IF it is likely to become energized.

I personally would not consider lightning as a source of potential energizing thus requiring bonding. At the same time, if lightning is the concern, perhaps the grounding system in place on those structures in question should be investigated for their performance and compliance with the NEC.

I simply don't see how simply "grounding" the gas piping will serve any purpose other than presenting more of a potential hazard.

 

[Foorsail]

Re: Coorigated Stainless Steel Tubing To Ground or Not to Gr

Thank you for your response. The article referenced in my recent post does not confirm or deny and investigation to the, then current method of bonding / electrode status. Good point.

PS. The link I posted does not work. It is the address given.

Have a good day.

 

[apauling]

Re: Coorigated Stainless Steel Tubing To Ground or Not to Gr

long deep breath, short answer.

One of my pet peeves that every one scoffs at is the allowance of the grounding tang of the device being energized as the bonding method that is allowed for gas piping. from the get go the CSST industry has pushed for this standard since there are no on-the-market listed devices for general bonding of CSST. If bonded it is done with brand parts for specific brands. CSST is not made to be clamped with any common bonding type connector.

Since the CSST is only bonded at one end, and that is to the grounding conductor, it is at some potential along its whole length to other conductive paths to ground. If it were bonded at both ends, it would be at the same (relaatively) potential as other bonding and grounding paths. I think this is one of the two main problems with CSST and near lightning strikes. The other problem is that CSST is allowed to pass through concealed spaces, partitions, and around corners, next to and along with long runs of electrical conductors.

Sure, CSST is a labor saving device, but there have been persistent and authoritive studies that link these gas lines with arcing that would not have failed in rigid gas lines. These studies are not done by unions and agencies secretely advocating for plumbers/pipe fitters as had been claimed early on. So there is a problem with allowing the CSST as installed.

CSST has been around in a different form as the allowed short appliance connections, that were NEVER allowed to be buried or concealed, nor allowed to pass through partitions.

Other gas piping systems are not failing at this rate, without direct hits, so there is a serious flaw in the design. The question then, is whether there is an installation where the CSST could be bonded without this propensity for arcing failure, or is the product flat out unsafe?

The other responses were actually quite a bit longer.

paul

 

[Foorsail]

Re: Coorigated Stainless Steel Tubing To Ground or Not to Gr

Thank you for your reply.

I agree and disagree. But that is not the intent of my posting. I am looking for any case study, applied rules, cases where CSST have been banned, or any other facts regarding CSST.

Your response is interesting to me; I am just looking for more facts regarding this product.

Thank you.