Copper Gas Line

[bend]

Is there any truth to the statement, The scent of the gas has an excess of hydrogen sulfide which is corrosive to copper gas line. I had an inspection yesterday where the water heater had a copper line run off the iron main pipe. In this area I had not run accross it before and was looking for help.

[Jim Katen]

Originally posted by bend

Is there any truth to the statement, The scent of the gas has an excess of hydrogen sulfide which is corrosive to copper gas line. I had an inspection yesterday where the water heater had a copper line run off the iron main pipe. In this area I had not run accross it before and was looking for help.

The scent added to gas is usually mercaptan. It doesn't have a corrosive effect on copper.

As far as I know, no one adds hydrogen sulfide to gas, but it sometimes occurs in the gas naturally.

The IRC says you can use copper tubing for gas if the the gas contains less than 0.3 grains of hydrogen sulfide per 100 standard cubic feet.

Here in the Portland area, we've used copper gas lines for years without any problems.

I'm curious. Where did you hear this theory about the "scent of the gas has an excess of hydrogen sulfide"?

- Jim in Oregon

[Chad Fabry]

It should be schedule K copper.

[Les]

We all have to be very careful with this one. Conditions are quite different with geographical areas. Type of copper tubing is critical re: suitability. For instance, the fuel gas here at my office in mid-michigan is a mixture of liquid natural gas from Louisana with nearly 0% h2s and aspirated natural gas from northern michigan with lots of h2s. The mercaptan used is a juniper extract and is corrosive along with the h2s. Nearly all the natural gas in upper michigan has h2s and will KILL you in seconds if inhaled. Bottom line, in our area K copper may be used with a flare mechanical fitting only. I have just touched copper gas lines that actually crumbled in my hands. We also had a contractor that piped a whole subdivision with sweat copper lines.

[bend]

I saw the statement in a reporting softwares pre-done comments/notes. It is not common, here to see a copper line for gas. I asumed it was ok as this particular home was well built and was built in 96. But you never know? I will check with the local gas company as well I think, just to be sure.

[DonTx]

I heard the same thing (stinky stuff in gas corrodes copper) and I believe our SOP requires us to call it out (I'm going to recheck now).

As I understand it, propane stinks naturally and is not corrosive to copper.

[Bruce Thomas]

Our local gas company allows copper feed lines but the main lines must be black iron or approved flex. I think it's a good ides for everyone to check.

Bruce

[Les]

Natural gas and propane are basically the same chemically. For our purpose the difference is pressures and combustion properties. I know some would argue with the carbon chain properties, but that is pretty esoteric for inspectors. This discussion would be a good addition to "Furnace Joe's" presentation on gas forced air devices. My best advice is check with local utility.