Electrolysis on Gas Pipe

ttekushan_2

Have you looked around for an electrical something or another around there that could be dumping current into the ground? I've read that in the past poor grounding of trolley lines would dump their ground current into the next available path, often a water line, making the water line relatively anodic. The impressed current could destroy a line very quickly.

Google "corrosion control" or "relative anode" or "impressed current corrosion control" or variations thereof. You may find information on some of those sites to get you looking in the right direction for the culprit.

-Terry

Alan(CaliforniaRadiant)Forbes

Electrolysis on Gas Pipe

This picture is of a section of underground gas pipe we installed about 3 years ago. The two leaks were located on either side of a coupling, each one the same distance away from the coupling.

The UPC requires dielectric couplings on underground gas pipe, but the local inspectors don't enforce it because nobody has ever seen electrolysis of steel pipe in this area. The building location is in a flat area near the bay where the water table is high, possibly a path for the electrons.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

This is not unusual

when pipe is not cathodically protected.

I have a lot of information about proper protection that I teach especially to the LP gas folks.

The answer is go to plastic pipe to eliminate this from happening.

This is the second leading cause of gas incidents the first is contractor damage to gas lines.

JK_4

I've seen this before

what we found to be the problem was a faulty earth ground from the building. I don't know if this is you're problem but we had holes that looked very simalar. good luck

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Alan(CaliforniaRadiant)Forbes

Do you

remember what was faulty about the ground? I see a grounding rod at the electric meter and the contractor tells me has a ground wire embedded in the concrete foundation.

Tim: Yes, we use PE pipe whenever we can, but this was a relatively short (80'), straight run and weren't concerned about electrolysis at the time.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Rodney Summers

Protective coating.

Protective coatings in the form of wrappings, tapes, enamels, epoxies, sleeves, casings and factory-applied coverings are a common method of isolating metallic piping materials from the atmosphere or from the earth in which they are buried. Application of these materials under strictly controlled factory conditions improves the quality control process and reduces the likelihood of coating defects. Corrosion can be caused by weather exposure, burial in soil or construction materials that are in contact with the pipe. Cinders (aka., dross) are waste residue from steel production and carry the waste products skimmed from the molten metal during the smelting process. Cinders are also the waste residue of coal-fired appliances and equipment. These materials are extremely corrosive to metallic piping and may not be used in any form (backfill or cinder blocks, for example) where in direct contact with the pipe. Protection is usually provided by a factory-applied coating or by field wrapping the pipe with a protective covering, such as a coal-tar based or plastic wrapping. Galvanized piping in contact with soil would require additional coating or protection. The zinc coating does not usually provide long term protection in underground applications. Where possible, a piping material is chosen that is not subject to the type of corrosion of the application.
Corrosion can also be caused by galvanic action that takes place where dissimilar metals are joined in a current-carrying medium, such as soil or water. For example, if steel and copper pipe are joined in a medium that conducts electrical current, the steel pipe will corrode at an accelerated rate because of the electrochemical process between the dissimilar metals. In this case, the soil acts as an electrolyte; the steel will be a sacrificial anode, and the copper will be a cathode. Because a cell is created, current will flow through the metal juntion and the soil, resulting in the gradual deterioration of the steel. To protect against galvanic corrosion, dielectric fittings and couplings are used to join the piping, thus breaking the circuit of the cell.
Most of time I've found people interpreted the code as requiring priming and painting of black steel pipe that is exposed to weather as the minimum form of protection.
If I were to ponder a reason why this happened in your case, I'd suspect the high water table in relation to the protection you used to wrap this pipe. You now see first hand the result of choosing this particular pipe over another (plastic) and the potential damage it may have caused.

Robert O'Connor/NJ

Alan(CaliforniaRadiant)Forbes

Oscar Wilde

said it:

"Experience is the name everyone gives to their mistakes."

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"