View Full Version : Mixing brass valves with iron pipe for gas

11-07-2008, 12:23 PM
I know some of you are not supportive of DIY work on gas lines. However, I did want to mention that this work has been discussed with our local plumbing inspector, and he has given it the green light. I would very much appreciate any comments / review of the following before I bring it to the inspector for final review.

The existing gas line is 1" galvanized, and feeds the furance and hot water heater. They are both within 15' of the gas meter.

I am installing a 30' extension to feed a gas range / oven. I plan to install a 3/4" brass gas ball valve at an existing galvanized "T", followed by 30' of 3/4" black iron pipe, and the final shut-off valve (brass gas valve) at the stove.

Is there any problem mixing brass gas valves with either black iron and/or galvanized pipe for a natural gas line?

11-07-2008, 05:05 PM
No problem . Dissimilar metal corrosion takes place in the presence of an electolyte ( water ). Gas...no problem

11-07-2008, 08:04 PM
Even with water, if you could not screw a brass valve onto a galvanized pipe, how would we ever be able to install any valve?

WV Hillbilly
11-08-2008, 12:34 PM
I see no problem with the brass valve but it's always been my understanding that natural gas shouldn't be piped through galvanized pipe . If I'm wrong why are you using black pipe for the 30 ft run ? Is black pipe cheaper than galvanized ?

Did some searching & found that at least in some areas galvanized is approved for natural gas . Live & learn .

11-08-2008, 06:08 PM
I haven't heard about any areas where you cannot use galv. for gas, but MA or NY might still have such rules. There is not a significant difference in price.

11-08-2008, 06:16 PM
My grandfather was a pipefitter. My dad always says grandpa taught him never to use any galvanized for gas.

Seems like this was an old rule that is no longer true? Anybody know why galvanized was not supposed to be used for gas and now it can be?

WV Hillbilly
11-08-2008, 08:19 PM
The old school of thought seemed to be that gas would cause flaking inside galvanized pipe & clog up orifices & such . Don't know what changed to reverse this idea .

11-10-2008, 08:07 AM
Thanks for the replies....

In our town, both galvanized and black pipe are acceptable for indoor gas piping. I know there are some potential concerns about galvanized, which is why I used black pipe for the extension. For me, material cost was not a concern (small difference), so I went with the black pipe.