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How to pressure test gas line?

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badtomatoes

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Jan 13, 2007
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Hi everyone, awesome site here. Been a long time lurker, now a first time poster. Anyway, I ran a gas line from my house to my detached garage. I have it capped near the house and just outside the garage right now.

I used buriable gas line from Grainger, adapted to 3/4" black pipe to make the connections on the ends. Can anyone explain how I can put something together to pressure test it?

Thanks for the help!
 
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regguy1

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badtomatoes said:
Hi everyone, awesome site here. Been a long time lurker, now a first time poster. Anyway, I ran a gas line from my house to my detached garage. I have it capped near the house and just outside the garage right now.

I used buriable gas line from Grainger, adapted to 3/4" black pipe to make the connections on the ends. Can anyone explain how I can put something together to pressure test it?

Thanks for the help!
Click to expand...

I used a T with 2 ******* and cap on each one, drill and tap caps for 1/8" pipe thread. Put pressure gauge in one and metal tire valve in the other. pressurize the line and note exactly where gauge is, if it has even a small leak the gauge will drop. If it drops...find leak and repeat process. I left mine on overnight. DO NOT pressurize any gas valve you might have in your system
 
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787B

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Baltimore, MD
As a poster discovered in another thread, watch out for changes in atmospheric pressure. Especially going from low pressure to high pressure. It will make you think you have a small leak when you don't. :)
 
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MrMark

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Southern Cal.
There is a gauge set with female 3/4 NPT and shraeder valve that you screw into the house piping where it connects to the customer side of the gas meter. You need to disconnect the gas co. spud from the customer side of the meter as you do not want to blow back into their meter. Don't touch the gas co spud on the supply side. You may need to loosen it to rotate the meter a little to unscrew the spud and ****** assembly from your new gas pipe assembly but don't remove it.

Remove all gas valves and flex lines and hard cap off the drops. Pump the system up to 15 psi using a bike pump and make sure you watch atmospheric pressure and temperature. Watch the dial for up to 24 hours to satisfy yourself that it is holding exactly at 15. Make sure you note the temp at the time of fill and check when the temp is the same, otherwise you will have movement.

You can get the gauge set at Home Depot by the gas shut off valves. It is relatively cheap and some of the best money you will ever spend.

I would check the system at mid point in your build out. Nothing worse than having a problem in the beginning and have to unscrew everything. But, maybe this is not an issue for you as your run is mostly plastic.

Put a new washer back on the gas co spud connection.
 
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badtomatoes

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Thanks for the input everyone. I'm heading to the Depot this afternoon to look for the gauge set. I looked before but never found anything. I dread asking for help at HD because usually it's worse than having no help at all...

Thanks again.
 
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MrMark

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How do you connect the yellow plastic to the risers?

How much did these materials cost you? How long is your run?


What size yellow line did you get?

I may use this stuff pretty soon .
 
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badtomatoes

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Jan 13, 2007
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Well, my thoughts were confirmed. Went to HD, asked the "plumbing guy" about a test kit and he knew nothing.

I'm now thinking about drilling/tapping the cap on one end for a pressure fitting and drilling a hole in the other end for a schrader valve.

MrMark,
My run is about 75' total. I used 3/4" PE tubing from Grainger. I want to say that the total cost for the tubing and fittings was just under $250.
 
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sevensandeights

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Apr 27, 2009
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Mckean, PA
My application is a little different but the testing apparatus I made should be similar for your needs.

I ran my own gas line from my house to my new barn and wanted to test the system before I backfilled the ditch. I used the yellow direct burial plastic gas line and stubbed it through the barn and house block foundations with a specical stub connector I bought a local plumbing supply house. The stub connectors were not cheap ($40 a piece IIRC) and you need a special chamfer tool that also cost $40. You cut the plastic gas line to length and then chamfer the end with the tool. Then, you push the chamfered end into the stub connector and it locks in place and can't be pulled out - kind of like a chinese finger trap. The stub connector is rigid plastic and goes through the block wall. The inside end of the connector has a 1" NPT male thread on it. On the house end of the gas line run I capped the line with a 1" NPT cap and on the barn end I installed my testing apparatus:

So, my testing apparatus consisted of of the following (in order):

1.) 1" to 3/4" NPT reducer (female-female)
2.) 3/4" ******
3.) 3/4" T
4.) 3/4" ******
5.) 3/4" ball valve
6.) 3/4" male air compressor quick connect coupler

On the 3/4" T port I put in a 3/4" male to 1/8" female plug reducer. This allowed me to thread in a 1/8" NPT low pressure gauge (0-15 PSI used for ATV tires).

I then fired up the air compressor and gently filled the system with air using the 3/4" valve to restrict flow from the compressor. Once I got to the desired pressure (I used 12 PSI) I shut the valve and then disconnected the compressor from the quick coupler.

I also used this same system to test the 3/4" black iron pipe lines that go from the stub connector to my gas boiler inside the barn.
 
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