Wrapping vs Coating for Underground Piping

[norzul]

Hi Guys,

Anyone got something to share on the protection of the underground (UG) piping?

For our project, based on the specification, the UG piping (firewater line and oily water sewer line) needs to be coated and wrapped. We had a meeting this morning & somebody mentioned that it is either coated or wrapped.

Just to check, what is the common practice in oil & gas industry? Is it adequate to just coated without wrapping with tape?

If we need to wrap, is it normal to do it at site or at factory? Do we have machine pipe wrapping? or is it practical/economical to do it manually?

Thanks

norzul

 

[norzul]

The total firewater line (6") is about 4km. The oily water sewer line (4") about 2km.

After further investigation, now I realize that there are 2 methods of UG pipe protection
1) TAPE WRAPPING - manual vs machine
2) COATING like Yellow Jacket

Prior to above, still need to do surface preparation of the pipe:
1) Blasting
2) Primer - coating (1st coat & 2nd coat)

For such a relatively short pipe (2-4km), is it economic to have COATING? I was informed that for very long natural gas pipeline, normally it is COATED...

Thanks

norzul

 

[SJones]

There are a number of factors at play here including: criticality of the lines, leak tolerance, application of CP, life cycle costs, etc etc. Shop coating will always give you a better quality coating but what then for the field joints? Tape wrap can disbond and shield the pipe from CP leading to corrosion. 'Coating' could also include spray painting if you are confident about the CP system design and the monitoring procedures. The principal point is that the coating will be the first line of defence against corrosion and that it is backed up by a CP system.

Steve Jones
Materials & Corrosion Engineer

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

 

[SlideRuleEra]

For electric power station construction we would specify that underground piping and piping embedded in concrete be "coated and wrapped" with asphalt and fiber materials, such as those described here

http://projectsmonitor.com/detailnews.asp?newsid=7977

http://www.SlideRuleEra.net