Pressure test on new natural gas piping.


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Old 05-05-09, 08:31 PM
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Pressure test on new natural gas piping.

Hey I replaced all of the gas piping in a granny flat on my property ... I already left it under 15 psi for 24 hours and it dropped 1/2 psi I have read that all is well if it holds 15 psi for 30 mins and it did do that but i still left it over night...should i be worried about that small drop in psi since the system is going to run at 1-2 psi.? and i bubble tested and i did not find any leaks. any input would be greatly appreciated.
 
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Old 05-05-09, 10:29 PM
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In my area the pressure of natural gas after the meter is less than 1/2 psi. The requirements in my area require testing at 3 psi. When you left the piping overnight it probably cooled and that cooling resulted in a lower pressure. If you were to wait until the next evening the daytime temperatures would likely warm the pipe and the pressure would return to the original setting.

I think you are okay.
 
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Old 05-06-09, 01:44 AM
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exactly what furd said. the drop in temperature overnight cooled the air in the pipe.

you are good to go
 
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Old 05-06-09, 07:26 PM
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Uh oh.......

I thought i seen bubbles on one end of one of my 90's so i took the 90 off reseales and now i let it sit over night at 15 psi again and it dropped 4 psi. i bubble tested and all of my joints dont show any bubbles.
 
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Old 05-06-09, 10:53 PM
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well now you do have a leak and its a small one. increase the psi to about 30 and see if you can find it.

it is most like in what ever you took apart or it might even be in the schrader valve you are using to put the air pressure in the line.
 
 

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