Sweating 3/8" Copper Gas Line?


Old 09-02-03, 06:07 PM
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Unhappy Sweating 3/8" Copper Gas Line?

I accidently bent a 3/8" copper gas line going to my fireplace. It was exposed near the basement ceiling where it heads into a wall cavity in the garage and the line is now pinched.

I'm wondering if it's "OK" to sweat a new piece of 3/8" copper line just like I have for water lines (MAPP gas and solder/flux), or does it have to be brazed, or does the whole run have to be redone, flared, etc... The gas pipe says 2 PSI Natural Gas on it, but this is after the regulator (I assume it drops the pressure to .5 PSI).

Since the connection is going to be enclosed inside a wall cavity, I want to be sure to do it right.

Thanks for your input!
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Old 09-02-03, 06:13 PM
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If you was a licensed plumber.......I would say yes.

A flared union would be less of a fire hazard.

Wait for more replies.......I'm curious to hear this one too.
Old 09-02-03, 06:17 PM
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I my own professional words, call and get help on this, I'd have to say replace the run of pipe from point A to point B

Gas fumes and fire don't mix to well,

Maybe someone else will tell you more.
Old 09-02-03, 07:01 PM
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I just followed the line through the garage and found that it goes through an exterior wall and then makes a 90 degree bend outside the house to turn into the side of the chimney/fireplace.

I can't see what type of connection it is though b/c it's covered w/ a larger grey plastic lining/pipe for protection. I would think it was either a sweated 90 or a flared 90 - no way to bend the tube that tight. It was put in by a contractor and inspected by the county at the time.

That's a good point on the fire hazard issue. If a fire cooked the line and it broke the solder joint loose, it could be REAL trouble.

What would you think of a flared union in the exposed part of the pipe in the garage (re-encapsulated in the pvc pipe protecting it)? I'd have solid pipe through the wall cavity to the connection to 1/2" black pipe in the basement.

I've run a good bit of black pipe before w/ no problem - was pretty straightforward. I'm definitely no expert, but have enough confidence to do this myself - just want to make sure I'm taking the right approach. Although, if it needs to be brazed, I'm not equipped to do it. I have a flaring tool...

Thanks guys!
Old 09-02-03, 07:15 PM
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Unless someone changed the code when I was not looking, copper joints are required to be brazed or mechanical (flared) sweating gas lines is not allowed.
Old 09-02-03, 07:24 PM
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I have been on site and watched plumbers and welders work on replacing all sizes of gas pipe. Everytime they use Nitrogen gas to purge the line before welding or brazing.
Old 09-02-03, 09:29 PM
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Even though I normally recommend the use of CPVC, I don't think I'll do it in this case. But I was wondering if there's a plastic alternative to the iron and copper pipes that are normally used for gas. I remember seeing some plastic like gas pipe on a This Old House episode some months ago but I don't remember what it was called.

Old 09-03-03, 05:28 AM
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No plastic pipe is allowed.

Many areas do not even allow for natural gas in copper due to odorant of gas corrodes copper. (there is a lined copper tubing that can be used)

(If LP is used, many more things to worry about)

Copper is brazed, never sweated.

Mechanical joints are allowed is some jurisdictions under specific circumstances.

Please call a licensed plumber and have this done properly and professionally. There are too many things that can go real bad. If there was ever a fire, you may or may not have insurance coverage for repair work on gas lines by non qualified persons.

Good luck and if you have any questions, ask away...
Old 09-03-03, 08:13 AM
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In my area.........alot of dryers were hooked with gas with on hard copper (m) using water lines for gas........? It is sooooo dangerous especially when they paint these lines and look just like water lines. Mind you,,,,,,plumbers did not install it this way.

Soft copper is allowed in my state but I don't use it. It also allows flared fittings.

Still..................it sounds better if a plumber on-site determines what is best at this point and take care of it this way.
Old 09-03-03, 11:24 AM
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I prefer regular black pipe, I've seen a fair amount of bent/punctured copper lines, but I'm yet to see a punctured black pipe.
Old 09-03-03, 12:25 PM
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I am a licenced master plumber and i would tear out all the copper gas and install black pipe.
Old 09-03-03, 06:35 PM
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I'm NOT a pro plumber, but I'm with trenchlessman.
I grew up in the East Texas oil field where everybody had natural gas.
Black pipe is the best way to go, but you can step it down safely with flared copper (just do it right).
Old 09-03-03, 07:39 PM
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Black iron will survive any fire in a house. It can withstand alot.

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