rust in gas pipes

[switchex]

Hi .. i have recently purchased an old house.. I have noticed that when i open the gas valve to the gas stove (which has not been installed yet), a lot of rust particles comes out of the pipe .. I have opened/closed the valve multiple times but the rust coming out doesn’t seem to get any less .. Does this have anything to do with the fact that the house has been vacant for more than 2 years and no one has used it? is it normal? should i keep running it until the dust stops or is it time for new pipes? .. i have never heard anyone changing gas pipes inside the house .. any suggestions?

[ralphtheplumber]

The gas itself contains moisture, and sometimes a small amount of sulfur which corrodes the pipes over time. There's a piping arrangement called a sediment trap or "dirt leg" that should minimize the amount of rust & scale that actually makes it out of the piping to the appliance.

You should probably have your local plumber out to inspect the piping and make sure everything's ok. It's kind of hard to judge these things over the web.

[PLUMBER RICK]

you probably might want to disconnect each fixture at the gas cock and replace them with newer gas ball valves. these will hold a proper air test 10psi. at this point you can put an air test on it. if it holds for 10 minutes, then i would use the air pressure to flush out the remaining rust. a compressor should be able to supply the necessary volume of air. keep in mind, only gas or air can be put into a gas system. regular house gas pressure is approx. 1/3 of a pound or 7'' water column.

if it doesn't hold a test, use a spray bottle with 50/50 soap and water to spray all exposed joints and check for bubbles with air in the line. keep in mind the older style gas cocks probably will not hold a 10psi test.

rick.

rick.

[plumbdog10]

Switchex,

I would suggest:

1) Removing the gas cocks and capping the ends of the lines with black or galvanized caps for testing purposes.

2) Disconnecting the main from the meter and installing a tee with a 15psi test gauge.

3) Charge the line with 10psi of nitrogen. The problem with using an air compressor is that it may inject more moisture into your piping, which if you have rust, is your problem now. You can rent bottles of nitrogen and a regulator at welding supply shops.

4) If it holds for 10 minutes go to step 5, if it doesn't follow Rick's advice.

5) Release the pressure from the piping.

6) Remove one cap. Blow nitrogen through the piping until there is no rust.

7) Recap the pipe and remove another. Blow out each gas outlet individually.

8) If you are still getting rust consider a repipe.

If the house has been sitting for two years some rust may be normal. An excessive amount may cause problems by clogging regulators and the orifices of your fixtures.

[PLUMBER RICK]

Switchex,

I would suggest:

1) Removing the gas cocks and capping the ends of the lines with black or galvanized caps for testing purposes.

2) Disconnecting the main from the meter and installing a tee with a 15psi test gauge.

3) Charge the line with 10psi of nitrogen. The problem with using an air compressor is that it may inject more moisture into your piping, which if you have rust, is your problem now. You can rent bottles of nitrogen and a regulator at welding supply shops.

4) If it holds for 10 minutes go to step 5, if it doesn't follow Rick's advice.

5) Release the pressure from the piping.

6) Remove one cap. Blow nitrogen through the piping until there is no rust.

7) Recap the pipe and remove another. Blow out each gas outlet individually.

8) If you are still getting rust consider a repipe.

If the house has been sitting for two years some rust may be normal. An excessive amount may cause problems by clogging regulators and the orifices of your fixtures.

dog is back in the house:)

dog, glad you came back home. i think you'll find a couple of interesting:confused: new posters here:eek:

mark checks in every couple of weeks too.

rick.

[switchex]

I sort of had the idea in my mind about blowing the rust out of the pipe using air .. except that I was thinking of using my shop vac and retrofit the hose, attach it to the main and blow air into pipe (Don't laugh! :-) .. i guess that was pretty stupid

Anyway, Here are a few (probably stupid) questions.

1- What is the point of the 10 min test? Is it to see if there is a leak some place?

2- Since the pipes are old, just wondering how hard it would be to disconnect the main from the meter.

3- So i can rent the nitrogen from a welding supply? How large are the nitrogen cylinders and how much do i need? Any danger in using them?


4 - Is there a name to this procedure, so that I can call a pro for pricing? How much do you think it would cost?


5- what is the life of these pipes anyway? never heard of an old house exploding becasue of old pipes!

Thanks again.

[ralphtheplumber]

#5 - http://www.sj-r.com/extras/galleries/gallerybox.asp?gallery=216

Switchex, I'm not trying to insult or discourage you, but gas piping is probably not a do-it-yourself project. Have another look at the last photo in the above gallery.

If you want to spray some soapy water on the joints and check for leaks, that's fine, but you can cause some damage pressurizing that system if you don't follow the procedures exactly.

[switchex]

thanks ralph .. i needed to see that picture to remind myself of my limitations .. if i do decide on doing the job, i make sure to hire a pro for final hookup to the meter and inspection. thanks again.

[Bob D.]

Dogs' procedure should work OK.
I would add when blowing down the line(s) to start at the closest point to your N2 bottle and blow down there first. That way you don't push junk through pipe you don't have to. You could use a clean white rag placed over the end of the pipe to see when you are getting it clean (once the big pieces are out and it is just the fines it can be tough to see).

Be careful with an N2 bottle, lots of pressure there, handle with care and don't transport with the cap off. Many people do it but the proper and SAFE way is to remove the regulator and install the cap when moving compressed gas cylinders. If you have never seen one of those safety films where the bottle takes off like a rocket and punches through a block wall you can't appreciate what one of these things can do if you let all the gas out at once :)


"never heard of an old house exploding because of old pipes!"

That's because nobody lives to tell the story :eek:

[plumbdog10]

Dogs' procedure should work OK.
I would add when blowing down the line(s) to start at the closest point to your N2 bottle and blow down there first. That way you don't push junk through pipe you don't have to. You could use a clean white rag placed over the end of the pipe to see when you are getting it clean (once the big pieces are out and it is just the fines it can be tough to see).

Be careful with an N2 bottle, lots of pressure there, handle with care and don't transport with the cap off. Many people do it but the proper and SAFE way is to remove the regulator and install the cap when moving compressed gas cylinders. If you have never seen one of those safety films where the bottle takes off like a rocket and punches through a block wall you can't appreciate what one of these things can do if you let all the gas out at once :)


"never heard of an old house exploding because of old pipes!"

That's because nobody lives to tell the story :eek:


Bob D. is talking sense, here. Important saftey factors. I have, as of late, attempted to be a kinder and more understanding Dog to homeowners. It isn't working. I basically grew up with construction, and I work with construction professionals. When I give advice to homeowners I often forget that what comes second nature to those of us in these fields are very much new to the handy homeowner. That is why I often give advice such as "Hire a plumber".

To tell you the truth, Switchex, I would consider hiring a plumber. Let him test the lines for leaks and make a call on a repipe. Ralphtheplumber (as a hugh fan of "The Honeymooners" I love the handle) is correct in saying that a gas repipe is beyond a homeowner project.

Don't save money over saftey.

[switchex]

thanks all .. Ok .. i'll promise to hire a pro for the job .. i am comfortable with all phases of construction as well and have done plumbing before .. but i guess i should not be working with gas pipes .. at least I now have an idea what to expect when i call a plumber .. ty.

[PLUMBER JAY]

I would agree that it would be a good idea to call a plumber, but if you were to do it I would use compressed air. i think the nitrogen is a little bit of overkill considering you are only going to have the air in the pipes for less than an hour. Also if you use air then you can really blow the lines out as with nitrogen you have to be careful as this will displace oxygen and possible cause a problem to your health.

[Bob D.]

The advantages of using nitrogen are it is clean, inert, and dry.
You can get clean, dry compressed air but not out of the run-of-the-mill home shop or jobsite air compressor. Since it is already established (or at least is the general consensus of the respondents) that you have a moisture problem then pumping moisture laden air in is not going to help.

I totally agree with the Dogs' statement:

Don't save money over safety.


It always cheaper to "Do It Right The First Time". If that means you have to hire someone else then so be it. At least every time you leave the house you won't be worrying if it will be standing when you get home.

[PLUMBER JAY]

Bob i am not arguing that a diyer should not touch natural gas!

I am only saying that if it was my house i would hook my air compressor up and blow the system out that way because i do not think that this will in anyway cause further problems.

Bob everytime you do a gas instal do you pressure test it with nitrogen or do you use your air compressor?
If it was your house would you buy nitrogen or would you use your air compressor?

[plumbdog10]

Plumber Jay,

Stick around and listen, you might,..........just might, learn something.

[Bob D.]

I am only saying that if it was my house i would hook my air compressor up and blow the system out that way because i do not think that this will in anyway cause further problems.

Yes, I would use nitrogen because I have seen first hand that it works better at drying out pipe lines.

Bob everytime you do a gas instal do you pressure test it with nitrogen or do you use your air compressor?

No, but the problem that this whole thread stems from is not present in the majority of installations. The difference between pressing up the line for a drop test and that of clearing the line out to remove rust and scale and moisture is that the latter pumps many cubic feet of air through the piping, where the former is only injecting a small amount of air into a closed system, enough to raise the pressure for a test but not even equal to the volume of the line, so very little moisture would or could be left in the line from my way of thinking.

I don't do residential installs, I do little residential work at all for that matter, mostly commercial, industrial, or utility work and new work at that.

When we are running a gas line it is usually a 4", 6", or larger main into the building. On these systems we have used air to test but they are new so the moisture problem is not present. Last job I did with any gas line work was a big kitchen in a hotel, we tapped into the existing 6" line and brought 3" into the new kitchen. The tap was done after midnight and in a couple hours the existing kitchens were back up and running before 5 AM the next morning making breakfast. We tested the new section with air when it was ready (about 250' of 3" on down to 3/4").

If it was your house would you buy nitrogen or would you use your air compressor?

As I said, if I was only looking to press up the line for a test, I would be happy using compressed air. But to try to clean a small bore line I would use nitrogen, though I will admit that compressed air would be better than doing nothing at all.

Depending on the condition of the pipe and what was captured in the rag during the blow down I would have to consider that maybe the pipe is corroded beyond a safe level (minimum wall might be violated) and replace it all. Without a UT (Ultrasonic Test) or other NDE of the entire line how could you know that there are not low areas where water has collected and over the years eaten most of the way through the pipe wall?

The moisture problem could be in the Gas Co.'s line out in the street somewhere. If when the pipe is disconnected from the meter and isolated from the utility lines there is evidence of moisture at that point it might pay to have the utility look into the problem too. Because if there is moisture present there then it seems to me it must be coming from the utility side of the meter.

[switchex]

ok, i wasn't going to ask any more questions .. but very curious to know what the average life of a gas pipe is anyway? The house that i am talking about was built in 1880 in baltimore city .. not sure what year they started having gas (any idea anyone?) but all homes in the city should have gas pipes with the same age ... is it possible that all Baltimore City homes have original gas pipes? .. i am just wondering if the gas companies have any responsibilty to inform and educate homeowners regarding the age of their homes and the gas pipes in them .. at a minimum, i would like to think that they change the meter/regulator after so many years in service, do they?cause most people who live in this area are very poor and uneducated

[Bob D.]

They can last a long time. I had a house in the 1980's that was piped for gas lighting when it was built in 1905. That pipe was still in service when I bought the place and when I sold it 8 years later, though I had disconnected all the red brass piping for the lighting, and was using only the 1-1/2" main to feed the clothes dryer, water heater, and the stove, which were the only two gas appliances we had. The reason the line into the house was 1-1/2" is because the old gas light system was very low pressure, only 2" WC is what I was told by some of the old timers I have worked with, so they needed the larger diameter for the volume into the house.

When the house was built it was also wired for electricity, but the service and whole concept of electric lighting was so unreliable and intermittent that gas lighting was also installed, and combination gas/electric fixtures to boot just to make things interesting :)

[Bob D.]

"with nitrogen you have to be careful as this will displace oxygen and possible cause a problem to your health."

Oh, I forgot to respond to this comment.

Since nitrogen comprises about 78% of the atmosphere I don't think we are in any danger of suffocating from the use of a bottle or two for a job like this. If we were working in a confined space or one in which it might be possible (say a small basement with little ventilation and/or limited access) to displace enough oxygen that we lowered the O2 level below 19% then we might have something to worry about and it is true that this situation should be considered and evaluated as it is possible. If the work were different and another gas was being used, say Argon to purge a pipe during welding, and the job required large amounts of gas, then it would be a totally different story and the likelihood of creating a depleted O2 environment would be much more probable.

[PLUMBER JAY]

Removes condensed moisture, oil aerosols
Also particulates from compressed air lines
Will provide clean, dry, oil-free air
Replacement filter for M-60 is M-723
One-year warranty


Bob I feel no real nead to argue anymore I agree that nitrogen is better than compressed air. Cost over value? (yes i know there is no price on saftey) And i agree that he should look into the integrity of the pipes. But with an air filter is compressed air possible up to your usable standards?
I am not trying to be a a** i am just throwing it out there.

[Bob D.]

Jay, I don't see us as arguing at all, this is a discussion of opinions and ideas from which hopefully we are all learning the pros and cons of each others views and beliefs as to what is 'the best' way to approach this problem, at least that is how I am taking it.

When you start hurling insults my way then we are past the discussion stage. I don't see this going or intend on taking this thread there; do you?
I've been on enough jobs and run enough crews in 29+ years to have heard it all, so anything anyone might say in a thread here is not going to phase me. They're just words.

You posted some info on a filter for an M-60, but I think some data is missing. Is this some type of inline filter for use on a compressor? If so, yes, they will certainly help. You can use air to do the job. You could also use a combination of the two to save money. Blow out the rust and scale using your air compressor, then follow with a purge of N2 at a low flow rate to dry out the line.

This is what the phone company does on some of their older trunk lines. You may have seen along the side of the road chained to a pole a bottle with a regulator on it and a tube running up the pole. This is tied into a truck line that the outer casing has been compromised on, mot times by squirrels who like to chew on the jacket or lead casing used at the splice points. Once the violate the integrity of the casing water gets inside when it rains. The old wires were wrapped with a paper insulation that would soak up the water and sometimes cause cross-talk between wires or shorting of wires and a dead line. So they would find the leak and patch it (using wiping solder years ago or more environmentally friendly methods now-a-days) and then pump a bottle or two of nitrogen through the casing to dry it out.

[PLUMBER JAY]

Bob i agree, I just did not want to come across like i thought i knew more then the guys that have been around for a long time.
The info on the air filter i found somewhere on the net. It was for use on an air compressor and i posted it just to help get a point across.
I would have to agree that a combination of compressed air and nitrogen sounds like a pretty good solution.

What about the other pros out there what route would use guys take?if by some chance you see a problem like this one day.

[PLUMBER RICK]

first off i would air test the entire system for leaks, using an air compressor or co2 bottle. (never had a nitrogen bottle. plenty of co2 bottles)

if it held test, i would then use the compressor to blow out the dirt, rust or moisture. if it had alot of moisture, i would hook a shop vac. to the line to either blow or suck the line dry for an extended period of time. air flow is what dries lines. nitrogen is just a dry inert gas. it is too costly to continue running bottled gas into the line to dry or purge the piping. a vacuum will do this for pennies of power:D

that's my opinion.

what do you guys think:confused:

rick.

[plumbdog10]

Bob i agree, I just did not want to come across like i thought i knew more then the guys that have been around for a long time.
The info on the air filter i found somewhere on the net. It was for use on an air compressor and i posted it just to help get a point across.
I would have to agree that a combination of compressed air and nitrogen sounds like a pretty good solution.

What about the other pros out there what route would use guys take?if by some chance you see a problem like this one day.

Plumber Jay,

I normally use nitrogen to test gas lines out of force of habit. I spent alot of years piping aerospace plants and government building where this was the specified testing proceedure. I continued to use it, if it was available, because I realized this was actually a better system.

Do I recommend that all systems be tested this way? No.

If I repiped my own house's gas system I probably would use air. My gas system would consist of less than 100' of 3/4" pipe.

I simply recommended it in this case because Switchex has an obvious rust problem.

As far as your concern about N2 in the house, you could blow the system out from the inside to the outside.

[switchex]

i am learning so much here and glad to have this topic posted. Thanks all …

I had called BGE long time ago about the problem .. i spoke to a lady and explained the "rust in the pipe" problem .. I don't think she had any idea about what i was talking about .. and basically said that if you have rust inside the pipe, it is your problem and you need to call a plumber . .at that time I wasn't thinking about the cause of the rust, which is moisture that most likely came to the pipes with the gas (i think that's what u all are saying) .. if that’s the case, every one in the city, or at least everyone near my block, is effected ... i will call them again and see if I can find someone more knowledgeable .. But don’t gas companies check for these things regularly? I mean, this could be effecting many homes and casing a very dangerous situation for all ...