CSST Bonding

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charlie b

charlie b

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Semi-Retired Electrical Engineer
At a training seminar last night, the instructor asked if anyone had Corrugated Stainless Steel Tubing (CSST) installed at their house. She looked concerned on my behalf when I said that CSST was used to run propane from my outdoor tank to my stove. The class subject at the time was local code changes related to lightning protection systems. She said that CSST had a history of causing leaks and fires when lightning strikes nearby. I have done some reading since. One source said that there are no documented failures of CSST due to lightning strikes, when the CSST is "properly bonded."

My pipe was installed by a plumber, without consultation with an electrician. It is on the opposite side of the house from the electrical service. My questions, for now at least, start with, what should I look for, in order to see if any efforts were made to ?properly bond? the CSST? If for example I find that there is a wire from the gas service equipment to the nearby outdoor faucet, should that alleviate all concerns? Or if I see no evidence of any attempt to bond the CSST or gas service equipment to anything related to the electrical system, should I be looking for the phone number of an electrical contractor? Does anyone have any knowledge or experience with this situation?

This is not a DIY question. I am not asking for help in fixing an installation. I want help to discover whether there is a situation that is in need of fixing.
 
I don't have the applicable Code at my fingertips, but I can tell you the mechanical inspectors in this area require a #6 bare from the CSST to the grounding electrode at the service.(Locally there is normally a hard pipe manifold for them to attach)
Here are some informative links:
http://www.csstsafety.com/CSST-FAQs.html
http://www.csstsafety.com/Images/CSST-Direct-Bonding-Tech-Bulletin.pdf?v=0SvS40oYMiE

(my understanding is that there is a CSST on the makert that does not require bonding beyond that required by 250.104, but local inspectors have chosen to bond all CSST systems alike rather than differentiate)

I'm sure there are folks on here that will provide you with better input, but this will provide a start :D
 
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charlie b,

You will need to know what type of CSST is installed [ i.e. - which
CSST manufacturer is your application ]......Once you know the
manufacturer of yours, then you will need to go to their web site
to look at their installation instructions.......Each manufacturer
has a different set of installation instructions.

I have attended Gastite' & Tracpipe' seminars on their product.
Here are some links:

Gastite: http://www.gastite.com/

Wardflex: http://www.wardflex.com/

Parker - Hannifin: http://www.parker.com/literature/Parflex/4660-PGP2T_September_2007_web.pdf

Tracpipe: http://www.tracpipe.com/About/CSST_Gas_Line_Manufacturers/

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Thanks, guys. I will take a look at the installation when I get home. I might try to take and post a photo.
 
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FWIW, the manufacturer' installation instruction are pretty detailed
on how to install their products.......Recommend that you read your
particular manufacturer' instructions closely.

As everyone already knows, even if a bonding conductor is
installed properly on the CSST, ...that's no guarantee that a lightning
strike won't exit off of that conductor onto a nearby surface [ i.e. -
the `ol "path of least resistance" thingy ] while following the
conductor to ground.

Lightning is an equal opportunity force of nature........It effects
everything around its strike points !

= = > < = =
 
IMO if you use T250.66 you can't go wrong to size the bonding for the CSST. The gas code requires that the bond be done where the gas pipe enters the building. Generally, as Gus stated, there is hard black iron pipe at the service and the bond is allowed to be attached to the black iron assuming you use an approved ground clamp. I believe it is a UL 467 listed clamp

Here is a pdf from eritech http://www.urbandale.org/document_library/building_services/requirements_and_guides/CSST_Bonding.pdf however they state #6 as hat is what the gas code requires. As North Star stated the manufacturer sometimes requires you to use T. 250.66
 
The settlement of the class action lawsuit seemed to indicate that this product has or had an issues with lightning. As far as the bonding required by the Fuel Gas Code or the manufacturer's to solve this problem, CMP 5 rejected code proposals that would have required bonding beyond what is required by 250.104, saying that there was no technical substantiation to show that the bonding will solve the lighting problem.
 
Dennis Alwon said:
Here is a pdf from eritech. . . .
Click to expand...
They list four things (on the electrical side, not the gas side) to which the bonding conductor can be connected. But at my house there is at least 100 feet between the gas service entrance and the electrical service entrance. So unless the connection can be made at the water faucet that is 2 feet from the gas entrance, and unless the water pipe is bonded somewhere within the crawl space under the house, then I don't know if it possible for this to be made safe. I will start by looking at the gas entrance, and see if there is any wire attached.
 
don_resqcapt19 said:
The settlement of the class action lawsuit seemed to indicate that this product has or had an issues with lightning.
Click to expand...
All I have been able to read today is that lawsuits have been won by the CSST manufacturers. What information do you have to the contrary?
 
charlie b said:
All I have been able to read today is that lawsuits have been won by the CSST manufacturers. What information do you have to the contrary?
Click to expand...
...A class-action lawsuit filed in Arkansas against several manufacturers claimed the tubing posed an unreasonable risk of fire from lightning strikes, leading to a 2006 settlement that was worth up to about $29 million, according to a copy of the settlement agreement provided by an attorney not affiliated with the case...
Click to expand...
http://www.huffingtonpost.com/2011/12/22/csst-gas-tubing-fires-concern_n_1164512.html
 
There are class action suits for a few new building product such as pex and a few of the major shingle suppliers.

We install a lot of csst for generators and I personally would never use csst for the main trunk line... For drops I don't have a problem

I have never seen csst run from a propane tank although I don't doubt it is done. I thought only coated copper was allowed to be run directly from the tank. Also the manufacturers of csst say it is legal to run outside but around here you would be hard pressed to find a ahj allow it without sleeving it.

How is it propane tanks don't have to be grounded/bonded?
 
Many will tell you instead of trying to figure out if it is safe or not (and still with no certainty) to just replace it with black pipe:happyyes:

There is a nonmetallic gas piping that has become pretty common for underground lines, but I believe must transition to something suitable for above ground usage where it emerges.

I question what may potentially happen if the gas line potentially is a better electrode then the electric service GE system and a lightning surge follows that path out to a tank full of combustible gas? Seems to me the non metallic piping underground would be more ideal for minimizing this "what if".
 
Got home late last night (taking an NEC 2014 update class), and it was too dark to do a thorough inspection. I was able to see that there was no CSST visible outside the house. A flexible pipe (that I could not see well) runs underground from the tank a distance of about five feet. It then stubs up to a service entrance thingy (pressure reducting valve?). From there a metal pipe runs to, and through, the wall of the house, into the crawl space below the first floor. I did not see anything that looked like it might be a bonding conductor. I believe that the CSST runs from that point, along the floor joists in the crawl space, to the area below the stove. There is a shutoff valve behind the stove, but I do not know if the CSST is run all the way to that shutoff valve.

The crawl space is not at all easy to access. But I will need to provide access later this summer, when I have the gas line tapped and run to the location of the gas burning fireplace we will be installing. I will take the time, while the plumbers are doing their thing, to look for a bonding connection somewhere within the crawl space.

Thanks for the assistance in gaining an understanding of this situation.
 
kwired said:
Many will tell you instead of trying to figure out if it is safe or not (and still with no certainty) to just replace it with black pipe:happyyes:
Click to expand...
And the CSST manufacturers will tell you (I read several accounts yesterday) that the black pipe has a known history of being even more susceptible to failure under lighting strike conditions than CSST has ever been.
So, tell me, which is better: breakers or fuses? Anyone from Bussmann here? Anyone from Square D? :lol:

 
charlie b said:
Got home late last night (taking an NEC 2014 update class), and it was too dark to do a thorough inspection. I was able to see that there was no CSST visible outside the house. A flexible pipe (that I could not see well) runs underground from the tank a distance of about five feet. It then stubs up to a service entrance thingy (pressure reducting valve?). From there a metal pipe runs to, and through, the wall of the house, into the crawl space below the first floor. I did not see anything that looked like it might be a bonding conductor. I believe that the CSST runs from that point, along the floor joists in the crawl space, to the area below the stove. There is a shutoff valve behind the stove, but I do not know if the CSST is run all the way to that shutoff valve.

The crawl space is not at all easy to access. But I will need to provide access later this summer, when I have the gas line tapped and run to the location of the gas burning fireplace we will be installing. I will take the time, while the plumbers are doing their thing, to look for a bonding connection somewhere within the crawl space.

Thanks for the assistance in gaining an understanding of this situation.
Click to expand...
If the line is not large enough to handle both appliances they may have to either increase it's size, run a separate line to the new appliance, or increase pressure and add regulation closer to the appliances. No matter what, that would be a great time to address what may be issues with the existing.
 
charlie b said:
And the CSST manufacturers will tell you (I read several accounts yesterday) that the black pipe has a known history of being even more susceptible to failure under lighting strike conditions than CSST has ever been.
So, tell me, which is better: breakers or fuses? Anyone from Bussmann here? Anyone from Square D? :lol:
Click to expand...
Just looking at the wall thickness of the two products, I can't see how it would be even physically possible that lighting could damage black pipe easier than the CSST.
 
don_resqcapt19 said:
Just looking at the wall thickness of the two products, I can't see how it would be even physically possible that lighting could damage black pipe easier than the CSST.
Click to expand...

Maybe damage at the junction points where the current has to flow only through the mating faces of the pipe threads? If you use the official yellow teflon tape, the only electrical contact will be where there is metal to metal contact cutting through the tape (which is required for the joints to be gas tight anyway and should happen with normal wrench tightening.)

I wondered about that too.

Some of the comments about greater risk with black pipe seemed to be conditioned on it not being bonded though.
I guess I will not bother looking deeper and hope that someone else on the thread will do the due diligence. :)
 
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GoldDigger said:
Maybe damage at the junction points where the current has to flow only through the mating faces of the pipe threads?

...
Click to expand...

With the threads tight enough to prevent leakage, I still think there would be a lot more mass at the threaded connection than you would have in the wall of the CSST.
 
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