Gunnar Alquist
12-01-2010, 06:32 PM
Today, I found buried galvanized gas piping in the rear yard at an inspection. Ok, actually, the galvanized gas piping exited the soil, so I believe that it is reasonable to assume that at least some of the buried piping is galvanized. The plumbing contractor at the site told me that galvanized piping used for gas does not require additional corrosion protection. He actually said that it should not be wrapped with the black PVC tape.
I looked through the UPC/CPC and found this:
1211.1.3 Protection Against Corrosion. Gas piping in contact with earth or other material that could corrode the piping shall be protected against corrosion in an approved manner. When dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders. Uncoated threaded or socket-welded joints shall not be used in piping in contact with soil or where internal or external crevice corrosion is known to occur. [NFPA54: 7.1.3]
As you can see, it does not specifically allow or exclude galvanized.
I followed-up by looking at NFPA 54 (Fuel Gas Code 7.1.3) and ended up with essentially the same paragraph. No help there.
I then looked at the IRC and found this:
G2415.8 (404.8) Protection against corrosion. Metallic pipe or tubing exposed to corrosive action, such as soil condition or moisture, shall be protected in an approved manner. Zinc coatings (galvanizing) shall not be deemed adequate protection for gas piping underground. Ferrous metal exposed in exterior locations shall be protected from corrosion in a manner satisfactory to the code official. Where dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders.
The IRC does not allow galvanizing on buried gas piping, that much is clear. My problem is that California does not recognize the plumbing portion of the IRC and uses the UPC. Is there anything in the UPC/CPC or NFPA 54 that states that zinc coatings are not good enough? I have been unable to find out what "an approved manner" is.
Obviously, I cannot tell what is going on underground or whether the threads at the elbows were wrapped, and I am going to defer on that basis if I can find nothing else, but I had thought that all metal gas piping had to be wrapped.
I looked through the UPC/CPC and found this:
1211.1.3 Protection Against Corrosion. Gas piping in contact with earth or other material that could corrode the piping shall be protected against corrosion in an approved manner. When dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders. Uncoated threaded or socket-welded joints shall not be used in piping in contact with soil or where internal or external crevice corrosion is known to occur. [NFPA54: 7.1.3]
As you can see, it does not specifically allow or exclude galvanized.
I followed-up by looking at NFPA 54 (Fuel Gas Code 7.1.3) and ended up with essentially the same paragraph. No help there.
I then looked at the IRC and found this:
G2415.8 (404.8) Protection against corrosion. Metallic pipe or tubing exposed to corrosive action, such as soil condition or moisture, shall be protected in an approved manner. Zinc coatings (galvanizing) shall not be deemed adequate protection for gas piping underground. Ferrous metal exposed in exterior locations shall be protected from corrosion in a manner satisfactory to the code official. Where dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders.
The IRC does not allow galvanizing on buried gas piping, that much is clear. My problem is that California does not recognize the plumbing portion of the IRC and uses the UPC. Is there anything in the UPC/CPC or NFPA 54 that states that zinc coatings are not good enough? I have been unable to find out what "an approved manner" is.
Obviously, I cannot tell what is going on underground or whether the threads at the elbows were wrapped, and I am going to defer on that basis if I can find nothing else, but I had thought that all metal gas piping had to be wrapped.