Question for Tim (underground gas line

Pinball

I have a question for the gas expert. Customer's house has a propane boiler. 500gal.LP tank on opposite side of driveway from house. (approx.50 ft.)The second stage regulator on house,is piped underground with 1/2" black pipe, sleeved in plastic conduit. It could only be burried about 12" down due to bedrock.Pipe stubs up about 4 ft. from tank, and was connected to the 1st. stage regulator with "L" copper(above ground), installed by the gas Co.

The brass fitting into the black pipe leaked after 5 months of service. Customer lost approx. 200 gals of fuel to the great outdoors! The rep. from the gas co. said it was from electrolysis, from customer, using black pipe underground. By the way, it was this same co that recomended the use of black pipe, because of the burial problem! Now They say, it was not their fault, and the customer is responsible for the repair and the lost gas!

Keep in mind, THEY did the leakdown test pryor to turning on the gas. and "certified " it's safety for opperation.

Have you or anyone else heard of something like this(electrolysis)and what are your comments and recomendations?
This is in New York if it makes a difference.
Thanks for your input


AL

lchmb

umm curious

Was it the fitting itself that let go or the threads leaking? Really curious on the black iron, how is it protected from rust? Did they seal it? Is there an anode bag attached to protect it? I'll let Tim take it from here, personally I would shy away from black iron underground.

Unknown

Electrolysis or (CORROSION)

Pinball yes electrolysis can occur when different metals are connected together and make contact with the soil. If that is expected a corrosion protection system can be installed such as an anode to neutralize the effect of electrolysis.

It sounds like this pipe is protected from that (sleeved in plastic conduit) unless there is any point that touches the soil without protection. By the way that pipe should be schedule 80 not schedule 40. Schedule 80 is thicker.

The thing that makes me wonder is that it occured after only five months. That seems very quick to me and it usually takes much longer than that for corrosion to set in.

Did the gas company do a block gauge test and a manometer test on this system? If they did any leak would have showed up at the time of start up.

It is possible with only 12" of cover that frost may have caused the pipe to heave and put some strain on the fitting causing it to leak. I am sure it has also had a lot of snow this winter in that area so that could also contribute.

Most LP gas companies that want to keep a customer would work out some kind of arrangement with the customer.
Let me know how they make out.

Pinball

It was the Threads that were leaking I saw very little pipe dope on it but there was some. And no ....no anode bag

Al

lchmb

Tim

Correct me if I'm wrong but couldn't they run CTS through the conduit? That would do away with the issue of corrosion and would be a little more forgiving to frost.

Pinball

Thanks Tim, the dept mgr is supposed to be there on Tues. to take a look see. I personally find it hard to believe in only took 5 months as well. but you do make some good points to consider. (frost heave, snow, and some contact with the ground by the Black pipe (where it extends up to the 2nd stage reg). I'll let you know as soon as I do...Just wanted an Idea here.

Any other Ideas on how to prevent this in the future giving the situation?

Al

Unknown

Better to use plastic

pipe from 1st stage to second stage with transition fittings coming out of the ground. You do however have to bury a tracer wire with the plastic. The folks who make the plastic pipe for LP use also sell the transtion fiting and tracer wire it comes all from the same people.

Unknown

If you are talking about CSST

some areas will not allow it underground. The other problem is the line from 1st stage regulator to 2nd stage has 10 PSIG pressure. CSST can only go to 5 LBS.

Weezbo

Pex-X-x? ithought it was rated for nat gas only ....

installing gas , propane no less ,under a driveway? could there be any other way to go ? like 2 80 lb tanks and a protected box along side the home? are above ground tanks allowed to be installed or are you basically stuck with below ground tanks where ever the gas company who owns the tank dictates?50 feet of pipe to get to the house ...i would think that the line would have to be deeper than the driven frost line for one thing and insulated and protected and identified..and Tested Prior to back fill...

Pinball

Hi Weezbo,

According to local codes the tank must be 25ft. away from the house(mininum).and 10ft. from a property line. and town road. this house is located on the corner of two roads. also the only way to bury a tank is to use lots of dynamite! (BEDROCK) less than 12" below the surface.also to put 80gal tanks next to the house is tough too. Windows,windows,windows! Gotta-see the great outdooors ya know! Which also leads to the reason for a 500 gal tank. HEATLOSS!!and bad roads in the winter.

Weezbo

Is the code on That Tank or is it for That fuel(LP)?just ....

curious... in bermuda they use a Jack hammer attachment for a back hoe to dig into the ground...luckily it is sort of a limestone...here in alaska we have bedrock and digging one of the "Pebbles" out would take some STOUT dynomite in deed:)

Pinball

any tank 500gals and over(LP) must be a min. of 25ft away
Yeah we could bring in the big guns.(excavator-mounted hammer) but the costs are alittle over the top for this cust. Also if he burried the tank he would HAVE to BUY it. above the ground, Co. supplied for free.it's a $$$-thing

Al

lchmb

Thats

Thats what I had meant Tim when I mentioned cts. Only other problem he may have is if the driveway is paved. I believe the tracer wire is supposed to be buried below the plastic so that when they energize it it won't cause an ignition or burn the plastic.

Plumdog_2

steel gas pipe in the ground

Twice I,ve seen steel Scotchcoat gas pipe corrode through in less than a year. Even with the wrapping and the goop to try and seal it from the soil, if there was any breech in the coating the electrolytic action would concentrate to a much higher magnitude at the point where soil and moisture made contact with the metal and burn thru quickly. As inexpensive as plastic gas coil pipe, the risers and the regulator sets are, nobody should put steel gas lines underground.
I worry about older homes that have the steel gas lines penetrating the foundation wall below grade.

Bart_2

In California

we are now required to use an IAPMO Listed Gas die-electric union. We had problems early on after the adoption of this section of the code cause nobody manufactured a listed fitting for this application but now they do. Our experiences with black wrap or epoxy coated black have shown that any failure in the wrapping system, nicks, cuts, or bad tape at the joints, can lead to a failure in a very short time. But five months is pretty darn quick..

Bart

EBEBRATT-Ed

Bury any metal in the ground becomes a battery do to the wet soil and the chemicles in the ground. I don't think that the electroylis could have happened that fast. Better to use the coated copper tubing or the plastic. Plastic is fairly expensive and requires a few special tools. The fittings are expensive but it is available for propane or natural gas.

Ed