Gas line not holding PSI

branimal

I'm renovating the 2nd floor of a 3 family house and before I reuse the cooking gas line I ran a pressure test. 10PSI. The pressure dropped to ~6PSI in 3 hours and still ticking.

Before I ran the test, I tightened up the closest pipe. The pipe runs down into a shafttway to the basement. So I don't have easy access to check for leaks.

Am I running my PSI test too high? I've done this on the 3rd floor and the pressure held at 10PSI for 24 hours. I've heard the gas company tests at 3PSI for 1 hour.

One option is to abandon the gas line and run electric for a stove.

Advice appreciated.

Location is NYC.

mattmia2

If it is iron pipe with no appliances or controls connected to it you should be able to test it at 100 psig. If there are any old style grease packed gas valves you may need to re-grease those(many valves aren't rated for the 100 psig). If you up the pressure you should be able to hear where it is leaking. If it is a pre 1920's or so building there may be capped outlets for old gas lights.

If the building is balloon framed you can connect and drop sections down the wall.

heathead

You may want to bubble test your test gauge and any fittings you have access to. Make sure you have no appliances hooked up to that line when pressure testing, if you do replace all the regulators because they are not rated for that pressure.

ChrisJ

No cap on the Schrader valve is where I'd check first regardless of the valve's history. Maybe you'll get lucky and it's leaking now.


10-15 PSI should be easy for black iron pipe to hold. I've done 150 PSI for compressed air without much difficulty.

I do not know what NYC's requirements are for a pressure test. Some places want lower pressure than others for whatever reason. Personally I test mine at 15 PSI or higher.

branimal

mattmia2 said:

If it is iron pipe with no appliances or controls connected to it you should be able to test it at 100 psig. If there are any old style grease packed gas valves you may need to re-grease those(many valves aren't rated for the 100 psig). If you up the pressure you should be able to hear where it is leaking. If it is a pre 1920's or so building there may be capped outlets for old gas lights.

If the building is balloon framed you can connect and drop sections down the wall.

There's nothing connected to the line. It goes straight to the meter. Which is locked and turned off. I put the account on hold for the renovation. I like the idea of pushing the pressure to 100psi and listening for the leak.

The building is from 1920, but the gas pipes are newer than that. That's my guess at least. Not sure what year.

ChrisJ

branimal said:

mattmia2 said:

If it is iron pipe with no appliances or controls connected to it you should be able to test it at 100 psig. If there are any old style grease packed gas valves you may need to re-grease those(many valves aren't rated for the 100 psig). If you up the pressure you should be able to hear where it is leaking. If it is a pre 1920's or so building there may be capped outlets for old gas lights.

If the building is balloon framed you can connect and drop sections down the wall.

There's nothing connected to the line. It goes straight to the meter. Which is locked and turned off. I put the account on hold for the renovation. I like the idea of pushing the pressure to 100psi and listening for the leak.

The building is from 1920, but the gas pipes are newer than that. That's my guess at least. Not sure what year.

Are you allowed to pressure test against the shutoff at the meter?

heathead

The answer is you must cap off. You can't test to the meter.

Lance

Experience has taught us that old systems were tested and passed at a 1/2 psi or less. It is easy to create a leak on old systems when testing at higher pressures. This will often make many joints leak. We know if a test must be done at say 20 psi on an old system, it is wise to be ready to fix a lot of leaks or just run new pipe. And don't forget old pipe valves and controls not rated for test pressure will leak and be damaged.

EBEBRATT-Ed

3-5 psi is the standard test for gas. you need to isolate and cap the pipe on both ends

pedmec

3 psi for 15 minutes for new work in Massachusetts. 1-1/2 psi for existing piping.

branimal

Here's the meter. Right side is the house side, left side is the street side. If the meter bar wasn't there I could cap off that vertical nipple. Not sure what to do here.

ChrisJ

branimal said:

Here's the meter. Right side is the house side, left side is the street side. If the meter bar wasn't there I could cap off that vertical nipple. Not sure what to do here.

Are you licensed to do gas work in NYC?
I thought there was no DIY in NYC?

@JohnNY Is that accurate, or can you DIY like you can in NJ assuming it's your own single family home?

JohnNY

Thanks for thinking of me, @ChrisJ
I'm not touching this thread. Gas piping laws in NYC are officially Draconian and this guy trying to cowboy it himself with that gauge and putting 10 PSI into his gas system is all I need to know. Cap that off with @mattmia2 telling the guy to put 100 PSI into his system, which the poster seems to think is a great idea, and I'm convinced there needs to be some regulation in place for giving mechanical advice online in this country. In the meantime, you guys have at it. I'm going to put my license and my gas certification in my pocket and go to work.

Seriously, folks. Stop advising this guy. He's on a bad path.

Steamhead

@branimal , @JohnNY is right. You need a pro. Gas is not a DIY job. Full stop.

WMno57

Your leak may be in the Schrader valve. Try re-seating the valve core with a valve core tool, replacing the valve core, and/or using a valve cap with a rubber gasket.

JohnNY said:

I'm convinced there needs to be some regulation in place for giving mechanical advice online in this country.

That would be a violation of the First Amendment. Erin may restrict speech on HER forum any way she pleases. The Government MAY NOT restrict free speech. The First Amendment does not allow someone to yell Fire in a Movie theater. I'm pretty sure this does not rise to that level.

WMno57

WMno57 said:

Government MAY NOT restrict free speech.

I should do more proof reading before posting. Is the above analogous to saying Hot Water Heater? Lets change that to "The Government may not restrict speech.

heathead

I agree with JohnNY about further advice. But you have pressure tested the meter to 10psi. You need to let the gas company know this, they may need to replace meter now. The first pressure test had things connected that shouldn't be pressure tested as you have done.

branimal

I found a leak in the line by spraying soapy water on the visible fittings by the meter. The house side nipple is connected to a 90 el. That 90 el is leaking.

I could hire a plumber to disassemble the pipes from the meter and tighten that 90 el, but who is to say if there aren't more leaks from the basement, toward the back of the building (55 feet) and then up ~20 feet to the second floor.

I think it's best to abandon the gas line and go electric.

EdTheHeaterMan

And if your car has a hole in the tire... Buy a Tesla?

EdTheHeaterMan

I am wondering who has the pipe wrench that put the pressure test gauge on in the first place? Maybe that person with the pipe wrench can take a few fittings apart at the meter and seal that leak with pipe joint compound or pipe sealing tape or replace the elbow with a new one if that elbow is actually defective.

But that is just me... even in a wheelchair, I can still turn a pipe with a pipe wrench.

ChrisJ

EdTheHeaterMan said:

I am wondering who has the pipe wrench that put the pressure test gauge on in the first place? Maybe that person with the pipe wrench can take a few fittings apart at the meter and seal that leak with pipe joint compound or pipe sealing tape or replace the elbow with a new one if that elbow is actually defective.

But that is just me... even in a wheelchair, I can still turn a pipe with a pipe wrench.

I'm betting that was a large adjustable, not a pipe wrench.

pecmsg

branimal said:

I found a leak in the line by spraying soapy water on the visible fittings by the meter. The house side nipple is connected to a 90 el. That 90 el is leaking. I could hire a plumber to disassemble the pipes from the meter and tighten that 90 el, but who is to say if there aren't more leaks from the basement, toward the back of the building (55 feet) and then up ~20 feet to the second floor. I think it's best to abandon the gas line and go electric.

Time to hire a qualified contractor!

branimal

EdTheHeaterMan said:

I am wondering who has the pipe wrench that put the pressure test gauge on in the first place? Maybe that person with the pipe wrench can take a few fittings apart at the meter and seal that leak with pipe joint compound or pipe sealing tape or replace the elbow with a new one if that elbow is actually defective.

But that is just me... even in a wheelchair, I can still turn a pipe with a pipe wrench.

Thanks for the nudge. Got the leaky elbow off - cleaned it off, put it back on with pipe dope. Plugged it. Tested at 10PSI. System is still leaking, albeit much slower. And I can't locate the leak.

Now it's a trade off b/w tracing the leak further back - which involves ripping up sheetrock ..... or replace with electric - which is almost zero cost b/c I'm getting a new subpanel and wiring installed. Looks like the stoves cost about the same b/w gas & electric.

ChrisJ

Did you apply 10 PSI to that gas meter?
Are you potentially pumping air back into a gas main?

Are you allowed to do your own natural gas work in NYC?

EdTheHeaterMan

ChrisJ said:

Did you apply 10 PSI to that gas meter?
Are you potentially pumping air back into a gas main?

Are you allowed to do your own natural gas work in NYC?

Looks like there is a lock on that inlet valve. I would cap off or put a plug in that elbow and test it again, while it is not connected to the meter.

Edit...

I saw you comment where you plugged it

ChrisJ

EdTheHeaterMan said:

ChrisJ said:

Did you apply 10 PSI to that gas meter?
Are you potentially pumping air back into a gas main?

Are you allowed to do your own natural gas work in NYC?

Looks like there is a lock on that inlet valve. I would cap off or put a plug in that elbow and test it again, while it is not connected to the meter.

Edit...

I saw you comment where you plugged it

I guess I missed where the meter was isolated from the system. My apologies.

I do see the shutoff is off and locked but that doesn't mean that valve seals against 10 PSI in it's current condition. It also doesn't mean that meter is ok with 10 PSI.

But as I said, I missed where the system was isolated from the meter.

branimal

The meter has been removed. The previously leaky 90 on the house side is plugged. That's what I'm running 10 PSI up against.

Going back to the gas vs electric discussion.... I'd love to give the future tenants gas. People prefer cooking with gas. But with the whole reduced carbon footprint push and some gas mishaps (buildings exploding) in NYC in the last decade it's becoming increasingly difficult to keep gas lines. Apparently NYC building owners now have to hire a licensed plumber to inspect the gas lines every 4 years. It's a fixed cost for the inspection (maybe a couple extra bucks for each additional line). No pressure test, they just spray visible lines for leaks. But what's to say 4 years from now they want to run a pressure test? I'd say that's a good idea. I can only imagine how many buildings have leaky lines.