Leak in pipe

John_37

I found it!

I had added a stud with a 90 degree elbow for a future patio Bar-BQ that I want to do. The elbow had a plug in the end and faced the skirting of the house. It was only a half a foot away from the skirting and close to the sill so it was hard to get your face in front of it. I increased the PSI to 40 (max for my gauge) and thickened the soap solution and was able to detect it. All that searching and frustration for a half a turn with a wrench on the plug. Argghh!

Thanks for the help.

John

PS In a way I’m sorry I found it. I was kind of looking forward to playing with one of those ultra sound gizmos.

John_37

Leak in pipe

I working on my own house. It is a very old house that was once cut up in to apartments. This gives me the luxury of being able to work on the original kitchen and bath while still being able to use one of the rental kitchens and bath. I’ve rewired top to bottom and run new copper for water. I‘ve now been running new black pipe for gas. I’m getting permits for everything and it is inspected and done to code. I know some of you are going to bark and yell that a non-professional should not be doing this. It doesn’t matter to me. I’ve got all of the time in the world and I enjoy the work so I’m going to do it any way.

I’ve run about 150 feet of pipe with maybe 40 fittings. I filled it with 20 psi of air to test for leaks. I made up a thick, foamy solution of dish washing soap and painted it on the fittings. I had to tighten down a union and I found a bushing that wasn’t seated properly. I also did not tighten down the testing gauge all the way. The leak slowed considerably but it has not gone away. I fill it to 20 psi and it leaks out over a 4 or 5 hour period down to about 4 psi. I have spent more time tracking this leak down than I did running the pipe in the first place. I have gone to every fitting and had standing soap bubbles sit there while I scrutinize it for a leak for several minutes. Nothing. I took the test gauge off and put it on a 2 foot piece of pipe to test it. I am at the end of my rope on this.

This is Tuesday. If I don’t find this thing by Friday I’m going to take all of it a part and redo it this weekend. Any insight to find this leak that can help me would be great. Please, for the love of God, don’t tell me to click on the “Find a Pro in your area” link. Time is not an issue and money is not an issue. If I have to throw all of this pipe away and start over from scratch that is what I’ll do to get this done and do it right.

John

John_37

Leak in pipe

I working on my own house. It is a very old house that was once cut up in to apartments. This gives me the luxury of being able to work on the original kitchen and bath while still being able to use one of the rental kitchens and bath. I’ve rewired top to bottom and run new copper for water. I‘ve now been running new black pipe for gas. I’m getting permits for everything and it is inspected and done to code. I know some of you are going to bark and yell that a non-professional should not be doing this. It doesn’t matter to me. I’ve got all of the time in the world and I enjoy the work so I’m going to do it any way.

I’ve run about 150 feet of pipe with maybe 40 fittings. I filled it with 20 psi of air to test for leaks. I made up a thick, foamy solution of dish washing soap and painted it on the fittings. I had to tighten down a union and I found a bushing that wasn’t seated properly. The leak slowed considerably but it has not gone away. I fill it to 20 psi and it leaks out over a 4 or 5 hour period down to about 4 psi. I have spent more time tracking this leak down than I did running the pipe in the first place. I have gone to every fitting and had standing soap bubbles sit there while I scrutinize it for a leak for several minutes. Nothing. I took the test gauge off and put it on a 2 foot piece of pipe to test it. I am at the end of my rope on this.

This is Tuesday. If I don’t find this thing by Friday I’m going to take all of it a part and redo it this weekend. Any insight to find this leak that can help me would be great. Please, for the love of God, don’t tell me to click on the “Find a Pro in your area” link. Time is not an issue and money is not an issue. If I have to throw all of this pipe away and start over from scratch that is what I’ll do to get this done and do it right.

John

Weezbo

Go Pro...Ultra sound detector residential 250$

you can get a new toy called an ultra sound machine...repressurize the pipe. gate it off. aim the thing at the general run of black iron the red light indicates the direction of the leak and the noise level in the ear muffs (Head set) indicates the intensity of the leak. the slide allows you to turn down the noise as you approach the fitting...once located spray soap and water the bubbles are where it is leaking. you can usually feel this with your hand . tighten that fitting. or there are other options my friends will share with you.

Jon_2

Leak in gas piping

First, insure you are not connected to any gas fixture, caps or plugs on all take-offs for appliances. Kick your pressure up to 50 PSI, use a 50-50 solution of Joy dishwashing detergent and water on all fitting. You will find the leak with the higher pressure and that solution.
Jon

Larry Weingarten

valves

The shut off valves used for gas don't hold pressure well. Cap those places and test again. I vote in favor of ultra-sound too. It finds the crazy-making leaks other methods don't. Or... plumbers used to test sewers with mint aroma. Got mint?

Robert O'Connor_7

First things first...

Don't be afraid, were not gonna bite......YET! I do have more questions than answers though. Is this a single family house that was turned into possibly an illegal multi family, and your turning it back into a single family? What state? Where is this union that leaked? Did you size the gas properly?.. Now for help. First off your typically not suppose to put unions in line before any branch valving, and NEVER EVER cover them up with any material that doesn't have access. Second, bushings are NEVER allowed on gas piping. Third, You test gas with 2 & 1/2 times the working pressure, Or, 5 psi. If you choose to test with a higher pressure, limit the gauge to a 30 psi MAX., and pump it up to half (or 15 psi). Never test through gas valves that are on the equipment. If your testing and have the gas cocks installed already, try checking there first, the gland/packing nut usually leaks. I personally don't have a problem with home owners doing their own work, provided that it's a single family, owner occupied house, anything else is NOT cool for you to do, nor is it legal. Finally, use snoop or a testing solution designed for the job. You would be suprised how much more sensitive the leak detecting solutions are.....Good Luck & your suppose to obtain the permit BEFORE you start work..Robert O'Connor/NJ

Weezbo

left right couples.....

Roberts sage advise ladd.... the gas is like "not" meant to be pounded into your home at high Pressures. valves are generally thrown away if they have the grease comming outta the gland..

ScottMP

I would be

interested to know what State allows a H.O. to do his own gas piping ?? H.O. doing his own plumbing, O.K. but what about the next owner. H.O. doing his own heat, well maybe if enough reading was done, the boiler part scares me alittle. BUT gas piping ? And all permits have been taken ?? Where is this allowed ?

Sorry to jump but I did not learn my trade in a few weeks with a "plumbing and Heating for Dummies" book. There's a reason for that and its because there is SOOO much to know.

Bushings on gas ?? Unions in the middle of a run ??

Scott

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Ken_8

Scott

It's allowed in most - if not all "rural" states. It's also allowed in rather urban states - like NY and NJ.

There is a secret formula that outshines them all - even the "expensive" "professional" grade bubbles used by utilities.

Car wash soap! Remember how it says to put one cap full for an entire bucket of cool water to wash an entire car?

Of all the bubble formulas out there, the bubble factor for car wash liquid detergent/soaps is among if not THE highest.

50# of pressure and a 1" wide paint brush with a 10:1 ration of water to auto wash has never let us down in 30+ years of being in this biz. And we do a LOT of gas pipe!

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kevin coppinger_4

gas testng.............

here in NH...most inspectors do not want us to test higher that 3 psi....and hold no longer than 10 min! 50 psi is way too high...especially for a system that will never see more than 1/2 psi under normal usage. Sounds to me like the high pressure will create leaks....yes here in NH you don't need to be licenced to run gas pipe and that is of some concern to me....kpc

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John_37

Thanks

Thanks for all of the sage advice. I'll see if I can cover all of the questions in this one response. The house was cut up in to apartments in 1922 and I am returning it back to a single family home. There are no appliances hooked up and all valves are capped. There is 1 union that connects to an existing pipe that feeds the third floor. There is 1 bushing (if I'm using that term correctly) that reduces a 1X1 inch T to 3/4 inch at 1 pipe (should that be a bell reducer). All of the pipe is either 1 inch or 3/4 inch.

I am testing at 20 PSI becuase when I took a course on residential electrical work the people who installed the gas pipe at the test house we worked on filled it to 20 PSI and it sat there for a week waiting to be inspected. Someone here suggested that 20 PSI could be causing the leak. Is that true? I would think this pipe would be able to hold 20 PSI.

Although I suspect now that the leak may be in the existing pipe (that I connected to with the union). I have tested and tested all of that pipe, however, I think today I will disconnect and cap the union and and test the two runs seperatly.

Also, is it possible to over-tighten pipe. I mean, could I have been too over eager when putting it together that I tightened too much. Sounds stupid to me, but as I said I'm going nuts here. Also, what size leak am I looking at here? If this is one spot that is leaking should I be able to hear a hissiing at 20 PSI or is this an extremly slow leak. If you recall I'm losing 15 to 20 PSI over a 4 or 5 hour period on 150 feet of pipe.

John

ScottMP

John

Pipe threads are tappered as are the fittings. A perfect joint is made when both line up. If a joint is over tightened, it can go past that point where the two threads mate.

Scott

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ScottMP

John

Pipe threads are tappered as are the fittings. A perfect joint is made when both line up. If a joint is over tightened, it can go past that point where the two threads mate.

Scott

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ScottMP

John

.

lchmb

one more question John.

Congrat's on finding the leak and wish you luck with all. Just one thing, did you verify that the pipe dope you used is acceptable with either propane or natural gas. Just want to make sure your safe...

hr

Wash all that soap off

soap is very caustic, when mixed strongly and will rust away at the threads. Dish soap will rust threads overnight, look and see!

NFPA 54 Chapter 4 defines "leaks shall be located by means of an approved gas detector, or use of a non corrosive leak detection fluid.." This was a question on my master plumbers test, I remember

There are leak detection sprays available at all plumbing supply outlets.

30 psi with a gauge in 1 psi increments is the methods inspectors around here prefer.

hot rod

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John_37

Follow up

It explicitly says on the label that it is to be used with natural and LP gas in vapor state. I actually read the label before I bought it! And to the other poster, I will wash the soap off, thanks for the advice.

I just got off the phone with the building department. I asked about their testing requirements for passage. He said 15 PSI for 15 minutes but they ask people to fill it to 20 PSI so the inspector does not have to stand there and look at his watch for 15 minutes. As for non-pros working on there own home, I don't think this is really a state or federal thing but I think it is determined by the municipality (city, county, etc) who has jurisdiction on the permit and inspecting.

I've owned my house for 2 years and have gotten 4 permits for electrical, water, gas, and asbestos removal (non-friable asbestos siding). They don't even bat an eye when I ask because I am working on my own home. Frankly, I think they are happy that someone is updating the systems on a house built in 1895.

I'm going to get inspection tomorrow and then it is on to do battle with the utility company. Because my house was 4 apartments there is an 80+ year old manifold for 4 meters. I want them to remove it and replace it with a single pipe. Let the games begin!

John

bob young

get ready for a serious explosion

bushings and unions are about the most illegal and dangerous fittings you could possibly use on a natural gas piping system. this coupled with your lack of professional experience , i would get a serious insurance policy because you are soon going to blow up your house and anyone who is in it. gas is to be highly respected and you are doing just the opposite.

John_37

Thanks for the insight....

Bob,

Thanks for your insight and comments. I come to this site to learn.

So, if it is currently holding 25 PSI of air then what is going to leak at the 1/2 PSI (or so) of NG. Also, how would one go about connecting to existing pipe without using a union? Do you rip out all pipe and start over every time you make a change? I guess I could have started at the one single existing 3/4 inch pipe and worked out from there (off the top of my head and not really thinking it through). Would this work in every situation? Also, if a union is OK in non-residential settings then why will they leak and explode in residential settings? Nothing is hooked up to service at this point so now is the time to make changes. Should I remove the bushing and with it with a bell reducer? Seems like the same number of threads. What is your advice?

I'm not being sarcastic in the least. These are serious questions. I want this done right. No one knows everything and we are all here to learn and exchange ideas. If Bob does not want to answer please someone else chime in. These are the kinds of comments that keep me up at night. Not because I think my house is going to explode but because of the lack of immediately apparent logic.

One more question. In another thread asking about what pressure NG is supplied from utilities everyone answered something like of 6” w/c or 7” w/c. What does the w/c stand for?

John

DaveGateway

Bushings

Since no one addressed this specifically, yes reducing couplings are required, bushings are a no no. If you venture away from the big box and into a supply house you will find the reducing fitting you need eliminating the need for either.

John_37

Thanks

I can get rid of the bushing easy enough. We don't have any "big box" stores around here. In fact, I've never even been in one. I got most of my supplies from a supply house. My neighbor has been a plumber for years and he was nice enough to call in a pipe order for me. They cut and thread and I picked it up - including the bushing. I used the bushing on one fitting because they were short on the number of 1X3/4 Ts I needed. I went to two local hardware stores and they were out of them too.

Why are bushings so bad? It seems like the same number of threads and it doesn't leak. Why are they such a no-no and if they are so bad why haven't they been pulled off the market?

John

Jim Bennett

Bad bushings.

Bushings are not allowed, particularly "one step" bushings as in 1" to 3/4" as they can be crudely manufactured and with threads on the inside and outside do not have a lot of "meat" to them. "Close" nipples (all threads) are not allowed for the same reason.


Though, I was at my brother's house last week and his gas meter was just moved from inside the house to outside. The work was done by a utility contractor and has a "tee" fitting with 1"x 3/4" bushings in both ends of the "run".


Guess it's just matter of "who" installs them.


We are going to change it.

John_37

Thank you

Thank you for clearing that up. That makes sense. I asked a few tiems in this thread and know one would tell me why. I must admit, though, that it seems that it would be fine in a realativly low pressure system as a residential gas line. I can see where you would never want to use a bushing in a commercial or industrial setting. The one bushing I used was used in the stud I installed for future use so it is easy to get rid of. I'll do it tomorrow before the inspector comes by. I doubt he is going to crawl under my house, but still, I want to do it right. Come to think of it the guy at the supply house suggested the bushing after asking me if this was for residential use.

John

Douglas Hicks

The natural gas company may have a leak tester that sniffs the amount of gas leaking from a joint. It is called, a sniffer.

The gas company may also give you some liqued leak detector, if you ask. I normally get a gallon at a time.

I have been told that bushings have less strength than a reducing bushing, also known as a bell reducer. However, in sprinkler work, we are allowed to use a bushing in an emergency situation. I have not seen a definition of "emergency".

Over tighting of fittings can and does cause leaks. A rule of thumb, tighten by hand and them six turns with a wrench.

Mike T., Swampeast MO

w/c

Stands for "water column"--another way of expressing pressure.

Water column is usually expressed in inches and is often used for low pressure applications as it is a very accurate measure.

1" of water column = 0.0360 psi

1 psi = 27.7612" water column

6" water column = 0.216 psi

A U-tube manometer is frequently used to measure pressure in inches of water. With a long tube in the form of a "U" you could measure the pressure of the natural gas by connecting to one leg and leaving the other open to the atmosphere. If the level of water in the other leg raised by 6" you would have 6" of water column pressure.

Besides natural gas pressure, water column is frequently used to determine air flow in forced air equipment. Then it's a differential pressure between the air on either side of the blower. Pressure difference is typically so slight that to get an accurage reading you have to greatly tilt the manometer. This makes a tiny change in pressure quite visible as water seeks level and a tiny change in elevation is magnified.

Many manometers (like the one in the photo) use a fluid other than water--generally more dense to keep the size of the "U" within reason and to make it easier to read, but are still calibrated in the equivalent of inches of water. Note scale resolution in the photo--major divisions to 1/10 of an inch, minor divisions to 2/100 of an inch or about 0.00072 psi!

Numbers across upper portion are in inches of water when the "U" is positioned vertically. Actual distance between "inches" is about 62/100.

John_37

Wow! Great explanation. Thanks.

I recall a rep from my utility said I got NG as "6 inch". I assumed that was some biz-lingo for PSI, but what that really means is I have less that 1/4 PSI coming in to my house. Interesting. I feel a lot safer no knowing my pipes will handle 25 PSI. I'm still going to get rid if that bushing, if for no other reason than I live in earthquake country. You never know what is going to give way when things start shaking.

John

John_37

More Bushings

I noticed that the meters all use bushings when attaching to the residential side of the service entrance. Hmmm.

As for pipe threads, I am a bit of a newby, but it does not seem they are all cut to the same quality. Some of those fittings were junk in my opinion. Because my house was cut up in to 4 apartments in 1922 it was an absolute plumbers nightmare under the house. I have cut out miles of gas and water lines from under there. Trying to get from point a to point b was impossible in some places. I also have 2 - 4 inch sewer mains for the house!

I was telling someone about all the 80+ year old pipe I was cutting out and they said I should save as much as I could because "they don't make it like that anymore".

John

DaveGateway

Codes

The code restrictions for the utility companies seem to be more relaxed than for "beyond the metering" which we must adhere to. I've seen plenty of Dressler couplings (compression type for black pipe) installed by the gas co in multi unit buildings. Our work must go beyond that and rightfully so as most of it is buried behind walls IN the residence where joint failure can be deadly.

Mike T., Swampeast MO

You're quite welcome. See now why pros start getting REALLY antsy when you start talking about doing your own natural gas (LP is even worse) work?

LOTS AND LOTS OF ENERGY = BIG BOOM!!!!!

Just imagine the danger in high pressure (measured in pounds per square inch) gas lines!

(I'm not chiding--am mainly just a DIYer myself--but I do harp on the fact that if you do this sort of work yourself you first have to be aware of the inherent danger, next you have to be certain you know what you're doing and lastly you should ALWAYS have your work reviewed--BEFORE it goes into operation!)

Matt Undy

Perhaps you might explain what is wrong with a union or a busing instead of just saying it is illegal and his house is goign to blow up. Personally I can't see how a bushing isn't oing to hold a foot or so WC. Unless there is some way something can shear off, I con't see the potential for a leak large enough to cause an explosion.

Matt

John_37

Yes but...

Everything you said is true but maybe not in my case. As you just informed me I am working in VERY low pressure. Also, I did say I am getting a permit and it is being inspected (in about an hour). In fact, the utility won't hook up to my pipe with out it being inspected. Lastly, later in this thread I did mention that I had consulted with a plumber who helped me size and measure pipe. If fact, he was the one who incouraged me to do this myself instead of farming it out. Now I should say that he knows me well enough to know that I have a decent amount of ability to do the job. He has been to my house and seen other work that I have done. I know that he would not encourage others to take on this job, and to be honest, others wouldn't want to. Crawling around in the dirt, cat poop, and spiders is not a job most home owners would want to do even if they had the ability.

I can underatnd you being nervous when you here non-pros wanting to take on something as potentially dangerous as NG pipe installation. The pointed questions and grilling are helpful. Most have been respectful of me here and I appriciate it.

John