Buried pipeline coatings

[kevlar49]

I have a buried pipeline that requires a new coating. The old coating is failing. It is a crude oil line, 20" OD, that is cathodically-protected.

Can anyone help provide me with guidance on which is more appropriate coal tar epoxies vs. phenolics and what are the pitfalls for their use?

We are currently looking at Sherwin-Williams Macropoxy 646 Fast Cure Epoxy. Anyone have experience with this product?

Has anyone found it useful to specify NACE RP-01-69?

Thanks for any help that you can provide.

 

[SJones]

Whichever coating you choose, it should have been qualified to your satisfaction using an appropriate test programme. If it's any help to you we have rigorously qualified Hempel Hempadur 85531

http://www.hempel.com/Internet/inecorporatec.nsf/vDOC/207FB384E7139219C1256BE4004DF139?OpenDocument

for our pipeline rehabilitation work.

Steve Jones
Materials & Corrosion Engineer

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

 

[kevlar49]

I have been asked to review the product polyken GO Coat 200. It is a solvent-based elastomeric primer with an elastomeric adhesive and a mechanical protection layer (tape, I believe).

Any experience with this system?

By the way it has ASTM G42 of 20mm which seems high. What do others think is an acceptable cathodic disbondment value?

Any help would be appreciated. Thanks.

 

[zdas04]

I've used Polyken primer and tape products for many years and have found them to excellent when properly installed.

I've also found that the roustabouts that pipeline companies use for that task need a lot of supervision and inspection. If you just turn green hands loose to wrap a fitting or weld gap you deserve the horrible results that you always get.


David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

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