# Connecting black iron pipe to soft copper



## The Engineer (May 4, 2010)

dave11 said:


> I'm looking to replace the last four feet of black iron gas line, leading up through a floor to an appliance above. The current pipe presses too tightly against a floor joist, and I'm concerned about movement of the wood due to seasonal changes, damaging the pipe. So I thought to replace it with soft copper, but no one has heard of a connector from black iron to soft copper. It would need to have a female connection with proper threads, and a flare fitting on the other end.
> 
> Anyone had to deal with this before?
> 
> Thanks.


Your going to get many different opinions on this. But the long and the short of it is, you have to conform to the national fuel gas code, which allows type K and type L copper tubing for gas applications ONLY if the gas contains less than .3 grains of hydrogen sulfide per 100 SCF of gas. Hydrogen sulfide is a corossive additive put into the gas stream which give the gas its oder, since natural gas by itself is oderless. The hydrogen sulfide will corrode the inside of copper tubing over time if the gas exceeds these limits. ALSO, you can't just solder the copper joint, it needs to be brazed with 1000 degree brazing material which requires very specific steps to prep the metals for brazing and a high temp acetylene torch. 

Your best bet, and my recommendation, is to keep the black steel piping and if you feel the joist will damage the pipe, then focus on lowering the pipe an inch or so before switching to a different metal.


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## dave11 (Mar 16, 2009)

The copper corrosion is not an issue here/ Both the gas company and the building inspector allow soft copper.

The issue is how to connect to black pipe. There's nothing in the Code that I've seen that disallows them to be mixed. 

It seems to me there must be a fitting made for such a purpose, but I have yet to find it. 

I would never attempt to braze black iron pipe. I don't think that's allowed.

Soft copper for gas lines is meant to use flare fittings. I don't see why there shouldn't be a fitting to transition from standard black pipe to soft copper--threads on one end and a flare fitting on the other.


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## COLDIRON (Mar 15, 2009)

You can get fittings that transition black pipe to copper flare I don't know if it meets code or not you can get brass NPT to flare, just screw in the brass NPT to the black pipe coupling/union with dope or teflon put your flare nut on the copper , flare it and connect it to the brass flare fitting.

Guess I will just wait and see how bad I get blasted for this one. Like I said I don't know if it's code or not.


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## kenmac (Feb 26, 2009)

We can use it here. It meets IFGC. You need a fitting that's example: 3/4 FPT female pipe thread X 1/2 SAE thread. Here we call it a 3/4 FPT x 1/2 SAE adapter. The fitting is brass. I believe the box stores have them


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## Plumber26 (Nov 10, 2010)

Code in my area say that any penetration through flooring, foundation walls, etc. must be made with black iron. Copper is too flexible to run through flooring and can easily be damaged doing so.

Well, code and common sense.


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## Bondo (Dec 8, 2007)

> It would need to have a female connection with proper threads, and a flare fitting on the other end.


Ayuh,... A brass ½ flare to ½ male pipe, to a 1" to ½ bell reducer will marry the pipe to the tubing...

Donno what your codes are,... 
Around here, soft copper is run from the regulator on the tank beside the house, straight through to the appliance...


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## kenmac (Feb 26, 2009)

here entire houses are piped with copper. IFGC has charts for sizing copper tubing


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