Oxidation on Copper Gas Line

[ccarrington]

I can tell you that in Texas, and in other parts of the country, the use of copper in a natural gas supply line is illegal. Gas companies add chemicals to the gas to give it an odor. (Different companies use different chemicals (or different quantities of the same chemical)) Some of these chemicals erode copper, normally from the inside out.

I can say as a fact that the Texas Real-Estate Commission will fine a home inspector $250 minimum, who fails to identify and report visible copper in a natural gas system. The commission will call you “incompetent” Here, we are required to use black iron, and galvanized is OK but not really recommended, I make a note of ANY material other than black iron (except flex connectors which are normally alum or SSteel)…

This is important, KABOOMMM…dead clients are bad press for your business… You can be pretty sure the fire department will have the cause of the explosion in their report. If you have already written your report and are in error, call the client and explain the confusion and the error, apologize graciously, then offer to help defray the cost in some way to make it safe for them… This is your business decision to make… But clients love honest inspectors, with high personal integrity… They will refer you in the future to other clients. Good luck.

Cort

[chris442]

Originally Posted by jfunderburk

Then why is it allowed? Is there really some scientific evidence that gas causes the metal to deteriorate? I'm not trying to be a wise guy...just trying to learn. As the code cited earlier in this thread shows, it is allowed.

It is illegal in MI, I know that. Here is an example from personal experience (I am an HVAC contractor).

Went to a business that sells gas fireplaces to repair a gas line. They have many fully operational fireplaces, all of which are piped with copper tubing over a dropped ceiling. Their furnace was also piped with copper. When they smelled a gas leak (Natural Gas), they tried to fix it themselves, but when they tightened the flare nut onto the fitting that was leaking, the tubing turned with it and twisted itself into a nice spiral kink.

When I cut out that 6" section of tubing to repair it, it was loaded with flakes from the inside of the pipe being eaten away. There were enough flakes in that 6" length to fill the palm of my hand. Imagine what that can do to the gas valve inside the furnace?

The whole building was piped in copper. I recommended it all be replaced, but no one seemed concerned with the pile of flakes I showed them. Oh, well.

Here in MI you can only run copper tubing for natural gas if it is tin-lined. Black iron is required, but some jurisdictions allow a minimal amount of galvanized to be used to bring the gas in from outside, then convert to black.

I know the code you cited seems to allow it, but it may be referring to copper that is "approved," and there may be a listing elswhere in the book telling exactly what type of copper is approved, such as tin-lined. Maybe it is legal there, but in areas where it is not legal, the above story helps explain why.

[Bruce M. Graham, III]

How many of you write up confined space gas line fittings(in the wall space) I see this all the time in new construction as well as older stuff.

[Barry Witt]

Gentlemen, the two components of natural gas that will corrode copper are h2s4 and moisture. They are present in varying levels depending on from which well field the gas is extracted. It would take many years for a typical copper tube to desinegrate but it will happen. Before that happens, however, the friable scale will probably build up and block orifices and screens of gas valves. Here is a link to a study by the CDA (copper development association) that gives some technical details on the matter:
http://www.copper.org/innovations/20..._Tst_Rslts.htm

This organization is not inclined to suggest that we stop using copper for piping gas but I certainly would. Natural gas is piped from everywhere in the country to everywhere else and one doesn't know how much h2s4 or moisture will be present in what is supplied at your location. Anyone who has done much work on gas heaters and appliances in Texas where these levels are high can tell you about plugged gas valve screens.

[Charley L. Bottger]

Originally Posted by Barry Witt

Gentlemen, the two components of natural gas that will corrode copper are h2s4 and moisture. They are present in varying levels depending on from which well field the gas is extracted. It would take many years for a typical copper tube to desinegrate but it will happen. Before that happens, however, the friable scale will probably build up and block orifices and screens of gas valves. Here is a link to a study by the CDA (copper development association) that gives some technical details on the matter:
http://www.copper.org/innovations/20..._Tst_Rslts.htm

This organization is not inclined to suggest that we stop using copper for piping gas but I certainly would. Natural gas is piped from everywhere in the country to everywhere else and one doesn't know how much h2s4 or moisture will be present in what is supplied at your location. Anyone who has done much work on gas heaters and appliances in Texas where these levels are high can tell you about plugged gas valve screens.

Thats no fun I have made a boat load of money cleaning black scale out of copper gas lines in my career????

That is the quickest way in this state for the gas company to turn your gas off and not back on until all copper has been removed. They do not even allow copper pigtails prior to the hot water heaters.

[sparksnmore]

Originally Posted by Barry Witt

Gentlemen, the two components of natural gas that will corrode copper are h2s4 and moisture. They are present in varying levels depending on from which well field the gas is extracted. It would take many years for a typical copper tube to desinegrate but it will happen. Before that happens, however, the friable scale will probably build up and block orifices and screens of gas valves. Here is a link to a study by the CDA (copper development association) that gives some technical details on the matter:
http://www.copper.org/innovations/20..._Tst_Rslts.htm

This organization is not inclined to suggest that we stop using copper for piping gas but I certainly would. Natural gas is piped from everywhere in the country to everywhere else and one doesn't know how much h2s4 or moisture will be present in what is supplied at your location. Anyone who has done much work on gas heaters and appliances in Texas where these levels are high can tell you about plugged gas valve screens.

In the last 35 years or so I've found "friable scale" flakes acually holding the gas valve open on a couple of natural gas water heaters, causing a run way condition in both cases.
Luckily for the home owners, both had good operating temperature-pressure safety relief valves.
I've also found the flakes in more natural gas copper gas lines than I can begin to count.