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-   -   Gas leak caused by pipe corrosion - Need Help (http://www.diychatroom.com/f7/gas-leak-caused-pipe-corrosion-need-help-108168/)

jaysen 06-19-2011 07:54 PM

Gas leak caused by pipe corrosion - Need Help
 
I know threads are worthless without pictures, but I'll explain first and provide pictures shortly after - forgive the incorrect terminology as I'll try my best to explain.

After purchasing my home in 2007, I poured some concrete in the backyard and built a fire pit in the center. I had the guys install a "T" connector at the firepit with a capped outlet about 10 ft away for future BBQ/outdoor heater use. The outlet was buried underneath the sod which was laid shortly after.

Roughly 2 months ago I began noticing a strong odor of gas near the pit. Originally I thought the ring was bad or the connection was coming loose. I retightened, added more teflon, and I thought the smell had went away. Fast forward to last week, the smell returned or to be quiet honest never left, I just could not smell.

So, today I dug up the yard where the outlet is located and I noticed where the pipe terminates it seems to be corroding just before the threading. I never paid any attention to the water pooling or constant soggy grass but after digging up I noticed a small pool of water a few inches away from the gas line - I'm assuming this is/was caused by the PVC/sprinkler pipe that was directly above the gas line. From what I read on the internet natural gas does not corroded piping, its a mixture of oxygen and moisture that will cause it to. I'm assuming the cap was not placed on the threading or sealed with a teflon/sealant and eventually the slow leak from the sprinkler ate away at the threading on the pipe.

I'm waiting for the ground to dry near the pipe but from what I can tell just by feeling around, the pipe just below the end cap is no longer cylindrical and round - I can feel lots of grooves or what ever you would call it.

So after the long explanation here comes my question;

How do i go about fixing this ? I'm assuming if I try and remove the cap, the pipe will most likely break off as it just doesn't seem like it would last much longer.

EDIT:

I found an old thread with pictures of my backyard progress when it was being constructed....
http://www.diychatroom.com/f16/build...-18336/index2/

Ishmael 06-19-2011 08:14 PM

They did a direct burial of black iron pipe?!?

oh'mike 06-19-2011 08:21 PM

Is the pipe long enough to cut off the defective part and cut new threads? A threader is not to difficult to use--they ratchet ,so the opening for the threader need not be to large.

Pictures would help----odd for the threads to corrode in three years----after repairing I strongly suggest a pressure check of the entire line.

A good plumber might be called for if threading a pipe is not in your book of tricks.---Mike---

jaysen 06-19-2011 08:37 PM

Quote:

Originally Posted by Ishmael (Post 670239)
They did a direct burial of black iron pipe?!?

Umm, It is the green coated gas line pipe at home depot. I told them when I purchased it was to be buried underground (concrete/dirt).

Is this the same?

Quote:

Originally Posted by oh'mike (Post 670243)
Is the pipe long enough to cut off the defective part and cut new threads? A threader is not to difficult to use--they ratchet ,so the opening for the threader need not be to large.

Pictures would help----odd for the threads to corrode in three years----after repairing I strongly suggest a pressure check of the entire line.

A good plumber might be called for if threading a pipe is not in your book of tricks.---Mike---

I'll provide pics here shortly but, I would say YES it is long enough to cut and re-thread.

oh'mike 06-19-2011 08:40 PM

Sorry,I'm not familiar with that pipe---Must not be used in this area.

jaysen 06-19-2011 08:54 PM

2 Attachment(s)
the part closest to the end cap is what feels corroded. the pipe as you can see in the first pic near the bottom is coated with a green coating of some sort. its black because I was scraping dirt away with shovel/pick

OldSingy 06-19-2011 09:12 PM

Buried gas line
 
Quote:

Originally Posted by jaysen (Post 670284)
the part closest to the end cap is what feels corroded. the pipe as you can see in the first pic near the bottom is coated with a green coating of some sort. its black because I was scraping dirt away with shovel/pick

====================

See the links below:

Your local jurisdiction may have additional requirements:

http://www.omegaflex.com/trac/techni...Omega_Flex.pdf

http://www.gastite.com/products.php?...g&idlink=link3

Regular black iron pipe should not be used in direct burial applications.

jaysen 06-19-2011 09:53 PM

I'm sorry I forgot to mention I'm in California. For what its worth; I called my local home depot and they told me the green pipe they sell is UV coated and approved for direct burial. Which is what I purchasd

Dougtheplumber 06-19-2011 10:38 PM

Even if the piping is certified for use underground, threads are not to be used underground, steel fittings only when welded, at least in my jurisdiction, and this is the reason.

jaysen 06-20-2011 09:03 AM

Quote:

Originally Posted by Dougtheplumber (Post 670366)
Even if the piping is certified for use underground, threads are not to be used underground, steel fittings only when welded, at least in my jurisdiction, and this is the reason.

And now I know why that is...

Well after further inspection, it appears the pipe at the threading is what is corroded. The cap is still held on pretty tightly however there is play when moved left and right - an opening in the line can be seen.

I have a Gas Company technician coming out to recommend me a solution/fix. Although after numerous calls and reading it appears replacing the line completely (which would require the ground be torn up) or terminating the gas to the fire pit are the only solutions. The latter is more an option right now than anything =/

UGHHHHH.

Here is my next question; The fire pit is connected to an outlet near the chimney. It is routed with a 90 elbow into the ground > to fire pit > T elbow > leaky capped outlet.

The only accessible piping, without tearing out concrete, are the pre-existing outlet from the house (at chimney) and a 90 degree elbow connected to 16 inches of exposed pipe (to firepit).

Theoretically would it be possible, of course after all the necessary precautions needed before doing so, cut the pipe off that extends from the ground and leads into the elbow. That way I can remove the elbow and cap the outlet at the chimney therefore eliminating the need to tear out concrete. I understand I will no longer be able to use the gas pit but thats easier to swallow then tearing concrete out.

TIA.

Dougtheplumber 06-20-2011 10:57 AM

Yes, that is the way to go, not a good idea to leave a leaking gas line in the ground that is close to a fire pit. When you finish capping the line, give it a good coat of rust prevention paint, use either yellow or the same color as your gas company so there is no confusion for anyone in the future as to what this pipe is.

OldSingy 06-20-2011 11:08 AM

Gas Line
 
Quote:

Originally Posted by jaysen (Post 670544)
And now I know why that is...

Well after further inspection, it appears the pipe at the threading is what is corroded. The cap is still held on pretty tightly however there is play when moved left and right - an opening in the line can be seen.

I have a Gas Company technician coming out to recommend me a solution/fix. Although after numerous calls and reading it appears replacing the line completely (which would require the ground be torn up) or terminating the gas to the fire pit are the only solutions. The latter is more an option right now than anything =/

UGHHHHH.

Here is my next question; The fire pit is connected to an outlet near the chimney. It is routed with a 90 elbow into the ground > to fire pit > T elbow > leaky capped outlet.

The only accessible piping, without tearing out concrete, are the pre-existing outlet from the house (at chimney) and a 90 degree elbow connected to 16 inches of exposed pipe (to firepit).

Theoretically would it be possible, of course after all the necessary precautions needed before doing so, cut the pipe off that extends from the ground and leads into the elbow. That way I can remove the elbow and cap the outlet at the chimney therefore eliminating the need to tear out concrete. I understand I will no longer be able to use the gas pit but thats easier to swallow then tearing concrete out.

TIA.

==============

Depending on your budget and access to the area, the new line could probably be installed using directional boring, which would not require additional excavation.

jaysen 06-20-2011 11:23 AM

http://dl.dropbox.com/u/9051346/IMG_...0_082456-1.jpg
Quote:

Originally Posted by OldSingy (Post 670613)
==============

Depending on your budget and access to the area, the new line could probably be installed using directional boring, which would not require additional excavation.


Old,

To be quite honest the cheapest/quickest fix is what I'm looking for - I've had the fire pit for nearly 3 years and it wasn't til 3-4 months ago when I finally installed the ring and decided to turn it on.

After giving it much more thought, I guess I could try and access the T elbow which is directly in the center of the pit, to continue the gas to the pit and eliminate the outlet however, seeing as these threads corroded after only 2-3 years I will not risk any more leaks.

Here's a pic of the pit and chimney where the fire pit is fed from

OldSingy 06-20-2011 01:48 PM

Gas Line
 
1 Attachment(s)
Quote:

Originally Posted by jaysen (Post 670623)
http://dl.dropbox.com/u/9051346/IMG_...0_082456-1.jpg


Old,

To be quite honest the cheapest/quickest fix is what I'm looking for - I've had the fire pit for nearly 3 years and it wasn't til 3-4 months ago when I finally installed the ring and decided to turn it on.

After giving it much more thought, I guess I could try and access the T elbow which is directly in the center of the pit, to continue the gas to the pit and eliminate the outlet however, seeing as these threads corroded after only 2-3 years I will not risk any more leaks.

Here's a pic of the pit and chimney where the fire pit is fed from

====================

See the sketch - not too much work and would permit the installation of a new bored-in line:

Attachment 34408


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