Natural gas line, pressure drop

[mvd7]

Have about 100 feet of new line that I've pumped up to 15PSI to test. And it's dropping over a 36 hour period to about 12 pounds.

I was recently told by local plumber that inspector will only need to see 10 pounds for 10 minutes, which my line holds no problem (and more). [Gas pressure here is only 1/4 PSI from the meter].

But I am still worreid that there is a leak. Should I be concerned, or go with the local plumber recommendation where he said, "don't even think of touching that pipe if it's only dropping from 15 to 12 over a 36 hour period!" ??

Thanks,
mvd7

 

[jayc]

I would be concerned. I put my gas line in on Saturday and pressure tested with 15psi. As of yesterday it was still 15psi. With the temperature changing it would fluctuate about 2-3psi, but has been coming back up to 15psi once the temp normalizes.

If you are actually losing air, you have leak. Soap test and find out where the leak is.

 

[HoosierBuddy]

Your local plumber is an idiot.

It could be that you are seeing a pressure drop due to a temperature fluctuation...so it MIGHT not be an issue. You need to observe the pressure over a period of time and see it drop to 12 psi and then stabilize for several hours (or even start to come back up) to verify that you don't have a small leak somewhere.

What I mean by "idiot" is I don't agree that a small leak on your brand new piping is acceptable...and without further information your pressure test isn't "PASS" it is "INCONCLUSIVE" which is the same as no test at all.

Phil

 

[rickairmedic]

I would never ever tell someone anything like that if you are losing pressure there is a leak put a few drops of dishwashing liquid into a spray bottle with water and spray all your joints if no bubbles then no leaks but if you see bubbles then you see a leak period . I wouldnt worry so much about an airline but this is a gas line and your pluber may be next in line for the darwin awards with that advice.


Rick

 

[dwilliams35]

a leak is a leak is a leak. I second the idiocy of the plumber. Just because all he knows is "long enough to pass a municipal inspection" doesn't mean it's right.

 

[Nealcrenshaw]

The plumber is correct!! If the pipe can hold the pressure for ten minutes you're good.I had the same problem.It would leak over the course of 12-24 hours,but it held up to pass the test,Got the gas turned on,and haven't smelled or touch the gas lines since that was over 3 months ago.

 

[IDASHO]

3 PSI in 36 hours??


What is the problem again??


That setup is good to go.

 

[oldgoat]

considering that your test pressure is way above the working pressure I wouldn't worry about it. If it makes you feel better go ahead and do the spray test.

 

[larry4406]

I would say you have a leak and should chase it. The fact that it is a "slow leak" and is not visible within the inspector's narrow time window of inspection (2 minutes?) is no basis to conclude that since you fooled the inspector you are good to go. A leak is a leak.

My buried poly gas line over 150' held pressure with no drop for at least a week. I have chased many leaks in threaded black piping only to find pin holes in the various fittings not my made up joints - had to pump the test pressure upwards of 90+ psi in order to get sufficient air flow thru the pin holes to make a soap bubble to detect it. It is unfortunate how many bad fittings there are out there. Make sure you isolate or disconnect any regulators, etc, before doing a system pressure test as most/many cannot tolerate high pressures.