How to pressure-test gas pipe

speedball1 · Aug 4, 2005, 05:43 AM

Quote:

Originally Posted by jamlove

Hi again!

First, MANY thanks to you experts for the help I've gotten in the last month. I passed my plumbing inspection for my new bathroom and kitchen!

Now, on to one more little one. I'm installing gas lines. The house was previously on oil heat and all other appliances were electric, so this is completely from scratch.

As is probably true in many places, our local codes say that the system must be "under test" when the inspector comes. It says to fill the pipes with 10psi of air, and that it must maintain the pressure for at least 15 minutes.

My question is, HOW? Is there some kind of device I've never seen that screws onto the end of a black iron pipe, but has a bicycle-pump connection for pumping air in?

Any help is greatly appreciated. I've been searching Google but so far haven't had much luck.

- james

Hey James, Welcome back!

Yes there's a device you can make yourself. You failed to mention the pipe size so I'm going to assume it's 3/4". You take a 3/4"(or your pipe size) coupling and bush it down to accept a snifter valve. A snifter valve looks like the air valve on your tire except it has threads at the base. Snifter valves can be picked up at some hardware stores and most auto parts stores. Since most air compressures the plug into a cars cigarette lighter have a gauge I would pump up the gas line with that or a bicycle pump with a gage.
OK! Yeah got 10 pounds of air in the gas line what now? We check for leaks by taking a mixture of water and dish detergent and painting each joint with it. If you see bubbles then you have a leak. No bubbles and you're home free. Good luck, Tom

jamlove · Aug 4, 2005, 06:48 AM

Great! I get it now. I'll go shopping for bushings later today! Probably will need a combo of several, unless I get lucky and make it to the specialty hardware store before they close this afternoon. Anyway, thanks very much Tom!

I'm a little surprised there isn't a commonly-found product for this sort of thing, but then again, I get the feeling that many homeowners are intimidated by gas piping and hire pros to do it. I'm not worried because, at this stage, if my house erupts and is sent into orbit, it'd be an IMPROVEMENT!

Just kiddin'.

Thanks again!

labman · Aug 4, 2005, 01:12 PM

The auto places that sell the valves don't speak plumber. They may call it a tank valve. At least a 3/4 '' pipe is 3/4'' pipe to everyone. Tubing is another matter. Plumbers always use ID. Many other use OD. Best to be very specific about ID and OD. I have been known to buy a pipe plug and drill a hole and tap it for 1/8'' pipe.

dmtnhwkc · Aug 14, 2007, 05:08 PM

Plumbing supply stores have a gizmo (I forget the proper name of it) that is a threaded metal cap. The threaded end is usually 3/4" pipe threads. The metal body has a Shrader valve on the end (like your tire valve stem) and a gauge threaded into the side. They are made specifically for pressure testing piping. Hopefully, you can find plumbing supply people who don't look down their noses at you for not knowing proper names of stuff.

DELMAWI · Aug 8, 2008, 06:09 AM

What is the ideal method ststement of the pipe pressure test?

Milo Dolezal · Aug 8, 2008, 06:21 AM

Yes: plug all ends, screw in Gas Test Gauge, take bicycle pump and pump it up. 15 lbs for 10 minutes should be fine. Home Depot, Lowe's, or Ace Hardware sells it. This is the gauge:

roark · Nov 4, 2008, 10:21 PM

Very helpful to see what this device looks like but... Where does it go? Outside at the gas meter in line or inside at the end of a line or? In the pic above, does it connect at the end of at the right?

Milo Dolezal · Nov 4, 2008, 11:13 PM

You can install gas gauge anyplace on your gas system past gas meter. Let's say: you disconnect gas meter on the right side of the meter. ( don't do anything with the left side of the meter. That side belongs to the Gas Co. ). Install gas gauge right there on the stub out that used to be connected to the meter.

Most gas meters are 3/4" but you may have bigger one, especially if you have pool heater. In this case, get reducer from the size you have to 3/4". Cap off appliances in your house and pump up the system.

It is not OK to leave gas valves (and gas flexes) at each appliance installed during the test. These valves are designed to hold about 3psi of pressure. They will leak giving you negative reading. You will be pumping up your system to 10 to 15 psi, depending on Local Requirements. That may be 3x more than what are these appliance gas valves tested for.

ezramace · Jul 2, 2009, 03:34 AM

Quote:

Originally Posted by Milo Dolezal

You can install gas gauge anyplace on your gas system past gas meter. Let's say: you disconnect gas meter on the right side of the meter. ( don't do anything with the left side of the meter. That side belongs to the Gas Co. ). Install gas gauge right there on the stub out that used to be connected to the meter.

Most gas meters are 3/4" but you may have bigger one, especially if you have pool heater. In this case, get reducer from the size you have to 3/4". Cap off appliances in your house and pump up the system.

It is not OK to leave gas valves (and gas flexes) at each appliance installed during the test. These valves are designed to hold about 3psi of pressure. They will leak giving you negative reading. You will be pumping up your system to 10 to 15 psi, depending on Local Requirements. That may be 3x more than what are these appliance gas valves tested for.

Milo, what about the fireplace key gas valve? How much psi can that sustain? In an older home 1980?

How to pressure-test gas pipe

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