gas pipe rust and paint - which paint to use? should I use inhibitor?

[Jamie]

I had an outdoor gas line installed recently (black pipe) and it began to rust within a week. I steel wool-ed it and coated it with linseed oil, problem solved and it looks so nice and shiny.

[Greg O]

Pretty much any underground gas on the utility side of the meter here is poly. Granted there probably is some steel in the ground here and there, but any new installs have been poly. The mains are poly, branches to homes and business' are poly. Greg

[JTMcC]

That's just not possible, PE is legal for pressures under 99psi, all in town distribution systems have pipe pressures well over that, they have to maintain volumn. Even a small town will have distribution mains running 200 to 500 psi. and from 2" up. As far as services go, steel services run off steel mains and PE services run off of PE mains. Maybe you haven't seen them, but there are quite a few steel lines in your area. You just can't run an entire dist. system with pressures under 99 psi. Especially in the winter. All this goes out the window if you are in Mexico, Gautamala, ect. But in the U.S. it will hold true.

JTMcC.

[Greg O]

Not going to argue with you, been there, seen them bury and connect mains. I was told by the utility that they run 50 psi in the mains, I have seen them run 2" and 4" poly. I know they have larger lines. Greg Greg

[JTMcC]

There is a large difference between "been there seen them do it", and "this is what I do for a living. A large part of our business is building gas lines, big and small. Like I said, we weld gas lines from 3/4" to 36", 2 psi to well over 1000. As for 50 psi in a main, a natural gas distribution system can be fairly complicated but the bone head version is this: The closer you get to the end of a particular line, the lower the pressure and the smaller the pipe. So to say a system runs at 50 psi is like saying my truck goes 50 mph, it does, sometimes. Many times it doesn't. The pressure in a particular line will vary at different times of the year, utilities bump it up come winter. I'm not going to argue with you either, you seem to be the archtypical internet expert, "I seen it done!" Good for you, but you are putting out miss information and anyone working in this field knows it.

JTMcC.

[Matt Whiting]

This is OK as a temporary solution, but the linseed oil won't weather all that long.

Matt

[Matt Whiting]

Well, I live in rural PA and my main distribution line past my driveway is 2" poly. It says so right on the yellow marker that sticks up out of the ground by my driveway. I'll have to check, but I believe the line from the main to my house is 1.5" poly.

I don't know what the pressure is, but I live out in the boonies and the distribution lines are pretty long.

Matt

[Greg O]

[Greg O]

Nothing I have posted in this thread is false, I work around this stuff nearly everyday, talk to the gents that do the work regularly. Maybe they do things differantly around your neck of the woods! I will not argue that fact that major, point ot point gas distribution is still done in steel. Once you get to the city scale of things the prefered pipe in this area is poly. Funny, what you say is impossible I have seen with my own eyes! I guess I was dreaming! Greg

[JTMcC]

What do you do, exactly?

talk to the gents that do the work regularly.

We work from coast to coast.

I'm sorry, but every time you say something you display a lack of understanding. What you just called distribution is transmittion. Distribution is defined by the piping system downstream of the town station. These are standard industry terms. Distribution piping is in town piping only.

Once you get to the city scale of things the prefered

Of course it is, it's cheaper, they use it in every case where it's legal to use, the problem is that higher pressure piping is required in the system.

It is impossible, with todays materials, to build an entire distribution system in plastic. Have you seen "with your own eyes" every underground main, station and service in the system? Of course not, trust me, in your area, if you are in the U.S., there are steel mains and steel services as well as plastic.

JTMcC.

[JTMcC]

Anecdotal evidence about the line in front of your yard is interesting, but I'm missing your point. There are millions of miles of plastic gas pipe in the ground, I remember when they used regular old PVC, and I've seen all the other incarnations of new and improved plastic line. When we test welders it is a common sight to see a whole gaggle of guys taking the plastic welding test. They use it everwhere they can, it's very cheap compared to welded steel line. I would guess that hundreds of miles are put in the ground every week, but that has no bearing on the fact that plastic at this point still has serious limitations on use, and millions of miles of steel is used in distribution piping as well.

JTMcC.

JTMcC.

>

[Greg O]

You know, I never said steel was not ever used anymore, just that steel use getting to be a thing of the past. Any low pressure, (less than ~100 psi), small diameter, pipeing put in in many places is probably poly. Steel is being used less and less. You won't see it much in our area. The origination of all this B.S, was the supply side of a residential meter, it would be poly in this area, as I am sure many others. Greg

[Greg O]

I just find it strange with your vast experiance you have never seen a poly riser with a steel jacket as stated in one of your previous posts. Here is a cut and paste from your earlier post.

I have never seen a steel riser to a meter in this area, They may exist, but poly with a steel jacket is many times more common. You made a statement that "All underground gas piping is either coated or taped these days." Kind of a broad statement, isn't it? You Then you go on later to admit to using poly for gas, which is it?

You ask what I do, I am a HVAC tech, and I do a ton of gas piping. Many times I have seen the utility dig in gas supply for a home or bussiness. EVERY time the tie in is to poly pipe. Some of the older parts of the city may have steel under ground, but the preferance is poly in this area. I have watched them bore and pull in poly gas main in new areas of the city many times, not a bit of steel getting dug in for the city's distrubution. I did watch them trench in a large transmission pipe this summer it was steel. It was not a main to my understanding as it just got gas from point "A" to "B", no branches going off. It was in the neighborhood of 12", but I did not actually measure it. Greg

[Mike Robinson]

I do not work in the gas industry, but a quick google revealed this

looking down the page:

1. The distribution system consists of both high-pressure mains (less than

60 psig) and low-pressure mains (1/4 psig), which distribute gas from the regulator station to the customer.

[Dan]

All the new distribution lines in my area are yellow plastic. Don't know about the high pressure stuff before that, but I presume it's steel.

Dan

[Jeff Six]

After all the advice, I got some RustOLeum Rusty Metal Primer and primed the pipe. I'll paint it with some nice paint next weekend. Thanks for the offer, though. :)

[Ralph Hertle]

Jeff Six:

Jeff Six wrote:

Rust prevention method:

This may be more than is needed, however, ......

Steel piping and structural steel beams may be effectively protected from rust where there is air and water, high humidity, or water condensation present by means of a block of zinc metal that is soldered or screwed to the steel. Zinc blocks function as a part of an electric circuit in water. the water on the surface completes the circuit. Instead of the oxygen in the air or water combining with the steel it combines with the zinc metal. Harmless zinc oxide powder is formed as the zinc is corroded away. The steel remains un-rusted.

The zinc may be attached with a stainless steel screw to the steel, and the zinc-to-steel contact patch must be clean metal to metal. The zinc and a small patch of steel around or near to the zinc is left bare metal.

Zinc is used on auto body panels and on steel hull boats or boats that have steel parts, e.g., prop shafts, that are in the water. The zinc blocks are replaced from time to time.

Purchase the zinc blocks and fasteners from any boat accessory or boat engine supply store. Several shapes are offered, e.g., disks or blocks.

Notice that anti-rust primer paints contain zinc. In water and oxygen when the zinc in the paint is used up the finish will fail and rusting will occur. A coating that totally seals the steel surfaces from water and oxygen will prevent the establishment of the electric circuit and rusting. Other metals will work, e.g., window frame aluminum in contact with steel, and the aluminum will be the sacrificial metal. Check the electromotive series in a chemistry book for a list of the metals that will work and that will not work. Use the wrong metal and the steel will be sacrificed by means of more rapid rusting.

Ralph Hertle

[JTMcC]

The gas company might take a dim view of you screwing or soldering onto the gas line. Gas distribution (and all other underground pipeline companies) companies spend considerable time/money on cathodic protection. Small amounts of electricity is run through pipelines, whenever a new service, or main extension, or any other significant addition or subtraction is made to the piping system they will take readings between the pipe and adjacent damp soil, and add large cathodic blocks as needed to bring the readings into their allowable range.

JTMcC.

Zinc blocks function as a part of an electric circuit in water.

[Ralph Hertle]

JTMcC:

JTMcC wrote:

]clip]

You are right: When writing I was focusing more upon fastening a block to the web of a WF beam than to the gas pipe. Clamping the block to the pipe would be appropriate. The same technique would work for steel or iron pipes.

Ralph Hertle

[Flash]

replying to Greg O, Flash wrote: I had black pipe rust right through and the power co. Turned my shit off, don't tell me it don't rust!!! Just looking for a suggestion on how to prevent it