# Gas line test (LP gas)



## anesthes (Jan 21, 2011)

So the inspector told me to put a test gauge on it, and it must hold 5 psi for 15 minutes. 

So I put a gauge on it, pumped it to 5 psi and it holds 5psi for at least 3 hours. 

It held the full 5psi for at least 3, however, I'm going into the 4th hour now and I notice the gauge is down to about 4 1/2 psi. 

Is that acceptable loss, or do you think it's a matter of the temperature change from this afternoon until now or?

-- Joe


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## hvac benny (Dec 29, 2009)

I would suspect a leak, unless the temperature really plummeted. Minimum code in all of Canada is 15 psi for 15 minutes, and many inspectors require a 30 psi test. I would always test at 30 psi for 24 hours, even for residential. There should be zero loss. I recommend you pump it up to 30 psi and soap test all joints. The added benefit of higher pressure is that you'll detect smaller leaks sooner.


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## anesthes (Jan 21, 2011)

hvac benny said:


> I would suspect a leak, unless the temperature really plummeted. Minimum code in all of Canada is 15 psi for 15 minutes, and many inspectors require a 30 psi test. I would always test at 30 psi for 24 hours, even for residential. There should be zero loss. I recommend you pump it up to 30 psi and soap test all joints. The added benefit of higher pressure is that you'll detect smaller leaks sooner.


The problem with that is that I cannot test at 30psi with the valves in place (ball shut off valves), and the inspector requires the test to be performed with the valves in place and the lines as they would be in service. 

I'll double check what the rating is on the ball valves and see the max pressure I can pump it up to.

-- Joe


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## hvac benny (Dec 29, 2009)

I would be very surprised if your shut-off valves can't handle 30 psi. The cheapest gas valves that I use are rated up to 600 psi. 

When installing gas lines, there are two tests that must be done:

1)The "rough-in" test: This is the 15 psi for 15 min test, with all meters, regulators and appliances disconnected. 

2)After you've determined that test one is good, you make all final connections (meter or tank, regulators and appliances) then either dial test or attach a manometer and test at operating pressure, AND soap test all connections made after test one. 

I realize that you are following what the inspector is telling you to do, but it falls short of even minimum code requirements where I am.


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## anesthes (Jan 21, 2011)

hvac benny said:


> I would be very surprised if your shut-off valves can't handle 30 psi. The cheapest gas valves that I use are rated up to 600 psi.
> 
> When installing gas lines, there are two tests that must be done:
> 
> ...


I had proposed #1 when I spoke with him, and he said no. He told me "Connect everything, turn your valves off and set it to 5 psi. I want to see it on for 15 minutes. 15 psi is way too high, these things run at half a psi on a good day".. I was like Ok. So I finished all my connections. Previously I had end caps in place of valves and I had intended on doing the 15 psi test, calling him to inspect, and then calling the gas company. (since the gas company does the 5psi test it seemed redundant that I should do it). 

Uggg!


Thanks for the help!

-- Joe


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## Plumber101 (Feb 25, 2009)

What code is your inspector using?


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## anesthes (Jan 21, 2011)

Plumber101 said:


> What code is your inspector using?


No idea. I told him I'd use the NFGC to size my pipes, and he said OK. 

Benny:

I used brasscraft vales. A couple 3/4, and a 1/2". They say on the tag they came with that they are rated for 1/2" PSI. Yet home depot says they are rated at 125psi... There is obviously something I'm missing.

-- Joe


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## hvac benny (Dec 29, 2009)

I use brass craft shut-offs on my test gauges to isolate the schraeder valve (they are prone to leaking after several uses) and they definitely hold up to repeated use at 30 psi. Look for the WOG number, I think 125 psi may be the correct max operating pressure. It should have something like '125 WOG' written on the valve.


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## anesthes (Jan 21, 2011)

hvac benny said:


> I use brass craft shut-offs on my test gauges to isolate the schraeder valve (they are prone to leaking after several uses) and they definitely hold up to repeated use at 30 psi. Look for the WOG number, I think 125 psi may be the correct max operating pressure. It should have something like '125 WOG' written on the valve.


I did another 5psi test just to see what happens. It lost 1/2 psi after an hour.

I'll go look at the valve bodies as you suggested and pump it up higher if I can. 

I hope if there is a leak it's now somewhere in the crawl space. It would be impossible to soap test there. 

-- Joe


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## anesthes (Jan 21, 2011)

They say on the casting/body "1/2 PSIG"...

Maybe I should just put some caps on for now and test it to 15psi (max my gauge will go to).

??

-- Joe


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## Plumber101 (Feb 25, 2009)

On all pressure tests here we break the appliance loose at the union and then remove the union and cap.

You really need to find out what code the inspector is using and what section. Not just the NFGC. Most codes are based off International Fuel Gas Code or the Uniform Plumbing Code.

Here we use the Uniform Plumbing Code which states no pressure against a valve. Meaning the shut off valves cannot be used as a cap. So we are require to disconnect the appliance being served and cap the line or plug the valve with it open.

Here we are required to test at 20 psi for 30 mins.

If I remember correctly code states that the gas pressure test shall be at 1 1/2 time the rated pressure for 10 mins. But with NG being at such a low pressure you will never find a leak at 3-5 psi so that is why we test at 20 Psi.


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## anesthes (Jan 21, 2011)

Plumber101 said:


> On all pressure tests here we break the appliance loose at the union and then remove the union and cap.
> 
> You really need to find out what code the inspector is using and what section. Not just the NFGC. Most codes are based off International Fuel Gas Code or the Uniform Plumbing Code.
> 
> ...


I'll try that tomorrow. I tightened the crap out of everything, so I suspect if their is a leak it's at one of the unions in the main line, since I'm told they tend to be the culprit. 

If something leaks, ever so slightly at 5, or 10, or 20 psi would it also leak at 1/2 psi operating pressure ?

-- Joe


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## ddawg16 (Aug 15, 2011)

We really need to know how much pipe we are talking about....if it's 1/2 PSI in an hour....and we are talking about 10' of pipe....yea...you have a potential problem...but if we are looking at about 100' total of 3/4" pipe with 3-4 connections on it....time to shag the wife...you have more important things to worry about.


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## Plumber101 (Feb 25, 2009)

anesthes said:


> I'll try that tomorrow. I tightened the crap out of everything, so I suspect if their is a leak it's at one of the unions in the main line, since I'm told they tend to be the culprit.
> 
> If something leaks, ever so slightly at 5, or 10, or 20 psi would it also leak at 1/2 psi operating pressure ?
> 
> -- Joe


After you put pressure to the line tap on the gauge to settle the needle. Pressure to 20 psi for 30 mins or an hour, if the needle moves then you have a leak..you want zero psi drop reguardless of size of pipe or length. If you have a drop in pressure get a reusable spray bottle and mix it with a liquid soap and water mix. Spray each joint and watch for bubbles. If you have no drop after 30 mins move on life is toooooooooooo short.


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## hvac benny (Dec 29, 2009)

ddawg16 said:


> We really need to know how much pipe we are talking about....if it's 1/2 PSI in an hour....and we are talking about 10' of pipe....yea...you have a potential problem...but if we are looking at about 100' total of 3/4" pipe with 3-4 connections on it....time to shag the wife...you have more important things to worry about.


No, this is absolutely wrong and dangerous advice. A 1/2 psi drop over one hour from a 100' section of pipe is a much larger leak than that from a 10' section of pipe.


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## anesthes (Jan 21, 2011)

ddawg16 said:


> We really need to know how much pipe we are talking about....if it's 1/2 PSI in an hour....and we are talking about 10' of pipe....yea...you have a potential problem...but if we are looking at about 100' total of 3/4" pipe with 3-4 connections on it....time to shag the wife...you have more important things to worry about.


Oh, jeez, let's see. We come into the house, have a shutoff and a drip leg with a T. We go back 12 feet to the water heater. The T then goes over 8 feet into another T. It goes back 30 feet to the range. Then it goes forward 10 feet to the furnace.

So technically, about 60 feet. There is two unions in the whole system BEFORE shutoff valves, just because it made life easier to build the pipe in sections, tighten it, then run it through the crawl space(s). 

-- Joe


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## anesthes (Jan 21, 2011)

I removed the valves and capped everything. I pumped it up to 15psi which is the max my gauge will read.

After exactly 30 minutes, it lost 3/4 of a psi, so it's at about 14.25. 

I tried the blue bottle of gas pipe bubbles stuff, but honestly I can't seem to find a leak. I'm not sure that it's significant enough to make an obvious bubble. 

I guess I'll have to just tried to tighten everything a little more...

-- Joe


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## Plumber101 (Feb 25, 2009)

Did you bubble test the schrader valve where you put air in.


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## anesthes (Jan 21, 2011)

Plumber101 said:


> Did you bubble test the schrader valve where you put air in.


No... I could try that tomorrow if you think it's a possibility. It's a brand new danco gauge.


-- Joe


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## Hardway (Dec 28, 2011)

hvac benny said:


> I use brass craft shut-offs on my test gauges to isolate the schraeder valve (they are prone to leaking after several uses) and they definitely hold up to repeated use at 30 psi. Look for the WOG number, I think 125 psi may be the correct max operating pressure. It should have something like '125 WOG' written on the valve.


(they are prone to leaking after several uses)
Please explain what leaks after several uses?


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## Hardway (Dec 28, 2011)

maybe your gauge is leaking down.


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## anesthes (Jan 21, 2011)

Hardway said:


> maybe your gauge is leaking down.


Well that would ruin my day...

Actually that is not a possibility. When Last night I shut off the main, and pressurized it to 5 psi. When I got home today at 4PM, it had held steady at 5psi. So the leak is after the main, but not in the gauge itself. 

I guess tomorrow I'll just cap sections at a time until I find the section causing the problem.


-- Joe


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## Plumber101 (Feb 25, 2009)

Probably a hidden joint somewhere.


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## anesthes (Jan 21, 2011)

Plumber101 said:


> Probably a hidden joint somewhere.


Bad union. Backed a few sections out, replaced it with a coupler, re-assembled and holds 15psi now.. 

Thanks guys!

-- Joe


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