Corrosion Resistant Underground Pipe 2

[UtilityLouie]

I just wanted to check if anyone had any ideas of what the new underground pipe treatment was to prevent corrosion. I have to install a small amount of underground pipe and think cathodic protection might be overkill.

The only real pipe that I know to apply is carbon steel pipe with coal tar epoxy and a wrap with special joint coating and taping.

Anything else out there that I should be aware of that works better, is cheaper, etc.?

 

[Zoobie]

What is going in the pipe (and at what conditions)? How big is the pipe? Why do you need to use carbon steel?

 

[UtilityLouie]

I was thinking CS because it's a short run underground.

I have a couple of pipes to install with a number of process fluids going through them:

- nat. gas (3")
- clean water (8")
- white water ( for paper machines ) (12")

Just looking for ideas...

I wasn't considering HDPE due to short length. I just didn't know if there was some new pipe coating out there...

 

[stanier]

Fusion bonded epoxy coating may be an option.

Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng

http://www.waterhammer.bigblog.com.au

 

[Ashereng]

Fiberspar linepipe is a good solution, at smaller diameters (4" typically) for natural gas, water, crude, etc.

http://www.fiberspar.com/news.htm

We are currently installing some. If you use a ditch witch, or plow, you can really install it fast.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[Drazen]

Yes, Louie, I exactly remember time when protection you mention was dominant for underground piping.

However, technology is advancing almost every day... Depending of service function of your pipe, I beleive ductile iron is the best choice - manufacturesrs sell pipe for undergorund installation with surface protection included. Even sandfill requirements are not so strict as this pipe is really robust.

HDPE pipe also does the job - can be used for virtually anything: water, gas, sewer (only high temperature limitations apply).

 

[thewellguy]

IF this is in the U.S. I would be willing to bet that if you put coal tar in the ground today, they would want to have a long long talk with you

 

[thewellguy]

I mean The E.P.A. would like

 

[mizzoueng]

ductile is probably your best bet. You can get it with an ashpaltic coating, and when wrapped in simple black 8mil plastic it lasts a long time. We are using it now for sewer service, nat gas, water, etc.

 

[unclesyd]

Here is coating details and standards for DI pipe posted above.

http://www.acipco.com/adip/linings/coatings.cfm

 

[JStephen]

Fairly common in waterworks industry is DI as listed above or PVC pipe with DI fittings. I don't know if PVC is compatible or usable with natural gas, though.

 

[KevinNZ]

For short run you could cover your steel pipe with a protective tape. Denso comes to mind.

Kevin

 

[SJones]

What you should be aware of is that no coating is perfect and that corrosion will occur at breakdowns in the coating. Cathodic protection will provide a back up to minimise corrosion at these breakdowns. So, the need for cathodic protection should be based on a risk assessment of how much corrosion will occur, how quickly it will occur, and what are the consequences of a breach in the pipe. Also, take into account possible interference from neighbouring buried structures that may already have CP.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[UtilityLouie]

Well, how about I compound the problem...

In this same area, I need to relocate some process sewer lines...

One line coveys waste with a PH = 2.0, the other two lines carry waste with a PH = 10.5. HDPE should be a no brainer, but the waste temperatures can reach 150-160.