New Gas Line with a Persistent Leak

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Old 02-11-16, 02:41 PM
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New Gas Line with a Persistent Leak

Hello all,

I ran a new black iron gas line for my natural gas conversion. After completing, I aired it up to 15psi. I found a couple of small leaks and fixed them.

I again aired it up to 10psi. It held for a day or so, and then it leaked a bit, so I replaced a couple of plugs and that seemed to solve it.

One more time I aired it up, and it seemed to hold good. I scheduled a time for the town to come by and perform their test (5psi for 15 minutes). They passed it without an issue.

I left it at 5psi (filled Tuesday 2/9). Today it is down about .75 to 1psi. Everywhere I read, it seems conflicting about drops in pressure, but this seems relatively small (compared to what others were experiencing). I can't tell if I am being a little to anal about this.
 
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Old 02-11-16, 02:50 PM
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#1, I know this is a DIY site but gas installs almost always require a permit, and only plumbers with a gas license or the gas company should have been doing this!!!

Edit: Not true. A plumber or the gas company is not alsways needsed as many states let the homeowner do their own improvements in their homes..
 

Last edited by lawrosa; 02-11-16 at 03:54 PM.
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Old 02-11-16, 02:53 PM
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Regardless of who performed the work, the leak is still there, so it doesn't mean much. Around here, you can pull your own permit and perform the work yourself. All of the proper permits were pulled and the line was fully inspected, and passed.

I'm just looking for opinions around the rate of the leak.
 
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Old 02-11-16, 02:59 PM
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Gas lines should have 0 pressure loss, any leak can cause an explosion.
It's your house, your family at risk, your call.



Edit... Not true . Ambient temps will cause the gauge to fluctuate due to expansion/contraction
 

Last edited by lawrosa; 02-11-16 at 03:52 PM.
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Old 02-11-16, 03:06 PM
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Granted, I have been a member of many forums, and there is a ton of snark, and unhelpful folks, but didn't think I'd pull one of those types on the first thread.

Gas pressure loss could occur without an actual leak, due to temperature fluctuations. So just saying it is a leak and dangerous, while it could be accurate, isn't really helpful.

I understand it is my call, but, again I am looking for some opinions, which you are entitled to and I appreciate, but no need to be **** about it.
 

Last edited by lawrosa; 02-11-16 at 05:06 PM. Reason: OP made a spelling error : )
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Old 02-11-16, 03:26 PM
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Don't mind Joe, he is very sure of his opinions whether or not they are shared by others. He has a lot of knowledge in many areas but just like everyone else he is not an expert in all areas.

Gas pressure loss could occur without an actual leak, due to temperature fluctuations. So just saying it is a leak and dangerous, while it could be accurate, isn't really helpful.
You are absolutely correct that temperature changes will affect the pressure. Are you certain that you are not losing the pressure where the air was added? Exactly what kind of fitting was used to add the air? A tire valve is commonly used and could easily be the leak point.

Yes, in my opinion you are being a bit anal. The rules that you have to meet, that it hold at 5 psi for 15 minutes, have been determined to be safe. While an absolutely tight system is definitely the goal to try to attain sometimes it is all but impossible.
 
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Old 02-11-16, 03:31 PM
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This doesn't address the acceptable loss of pressure, but have you performed another leak test?

Use a gas leak detector fluid versus soap and see if you can produce bubbles.
 
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Old 02-11-16, 03:50 PM
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Probably from 2/9 to now that is has been bitterly cold you will drop pressure.

When I test my gen installs I pump the line up to about 50 psi. I do a a soap test..

The weakest link IMO are the unions. I use the 500 lb'ers. They have a brass matting surface.. If you use the 150's they do not from what I know..

This I say too as long as you turn the fittings on the required depth.. Also I use teflon tape and dope on the threads..

More often also I say its the unions because in the 3 months at my new job we have had 4 unions leak so far.. Thats not a good percentage.. ( I blame it on china, but thats just my opinion)

Im suprised the inspector passed you.. Often code as I know it everywhere is to pressure test for inspection @ 1/2 the gauge.. We use 30 psi gauges and test @ 15psi..

So you had a 10 psi gauge? I think not as you stated you aired up to 15 psi...
 
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Old 02-11-16, 03:57 PM
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You are absolutely correct that temperature changes will affect the pressure. Are you certain that you are not losing the pressure where the air was added? Exactly what kind of fitting was used to add the air? A tire valve is commonly used and could easily be the leak point.
I used a schrader valve into a gas ball valve with the gauge in between the valve and the line going into the house. It seems like it isn't leaking, I've sprayed there as well, and re-tightened it all.

This doesn't address the acceptable loss of pressure, but have you performed another leak test?

Use a gas leak detector fluid versus soap and see if you can produce bubbles
It isn't hooked into the gas line yet. I have held off on that, until I can decide if the leak is too much, so all I can really do is soap test.

Probably from 2/9 to now that is has been bitterly cold you will drop pressure.

When I test my gen installs I pump the line up to about 50 psi. I do a a soap test..

The weakest link IMO are the unions. I use the 500 lb'ers. They have a brass matting surface.. If you use the 150's they do not from what I know..

This I say too as long as you turn the fittings on the required depth.. Also I use teflon tape and dope on the threads..

More often also I say its the unions because in the 3 months at my new job we have had 4 unions leak so far.. Thats not a good percentage.. ( I blame it on china, but thats just my opinion)

Im suprised the inspector passed you.. Often code as I know it everywhere is to pressure test for inspection @ 1/2 the gauge.. We use 30 psi gauges and test @ 15psi..

So you had a 10 psi gauge? I think not as you stated you aired up to 15 psi
The air temperature has dropped. Especially today, when the pressure loss was most noticeable. We didn't have any code around the gauge itself. The gauge I have on there is a 30 pound.
 
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Old 02-11-16, 04:50 PM
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When I did the gas line at my parents house the inspector wanted 3psi for 24 hours. I used a 3 psi gauge (not easy to come by) and pumped it up to that pressure in the early afternoon. The inspector came by the next morning and it had dropped to about 2-3/4 psi. My daddy offered to pump it back up but the inspector said no and then "blipped" the pin on the tire valve to make certain the gauge would move. After that he was happy.
 
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Old 02-11-16, 05:20 PM
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he gauge I have on there is a 30 pound.
Pump to 30 and soap test all joints... Let soap sit a few minutes and then have a look see.

slow leak you will see very very small micro bubbles growing a bit.. Hard to explain unless you know what to look for...
 
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