Wrap-type coating qualification for the splash zone 1

[EliasS]

Greetings,

Are there any standards to qualify wrap-type coatings for the splash-zone for offshore structures and risers?
The product alternative that I am looking at is a composite, consisting of a membrane wrap + resin.
I am aware of NACE TM0404 but it excludes such type of coatings.

Also,are there any general objections or resereves for such type of coatings for plattforms and risers?
It seems that the industry prefers to use continuously applied coatings as those covered by NACE TM0404.

Any reference towards information on coating selection that includes composites for splash zone in offshore oil and gas applications would be much appreciated.

EliasS.

 

[TugboatEng]

Are you repairing existing structures or wrapping new construction? I think wraps would not be acceptable on damaged metal due to its inability to conform to pitting. They're are certainly paste type options. Many can be injected under a wrap.

https://www.belzonanorcal.com/en/focus/splash_zones.aspx

Injection under a metallic wrap:

https://khia.belzona.com/app_know_how/KHIAXXV/xxv_no_5.pdf

 

[EliasS]

The application I am looking at is for new construction, mainly for surface casings in shallow water wells.

The resin injection solution that you kindly mentioned is mainly used to repair heavily corroded pipelines or platform legs while in/service.

Regards,
EliasS.

 

[SJones]

https://www.cs-nri.com/category/industries/offshore/

I can't think of a corrosion protection spec for wrapping, but a pressure containing repair would be governed by ISO 24817

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[TugboatEng]

On our vessels with water lubricated strut and stern tube bearings with carbon steel shafting we wrap with two layers of bi-axial fiberglass tape and impregnate with resin. We prefer this is done on "as-machined" shafts with no profiling as the coating is easier to remove for repair, it can be peeled off. Profiling will give tighter adhesion. American Bureau of Shipping likely has guidelines. The system works quite well, even in shrouded applications where muscles and other debris might get caught between the shroud and shaft.

I am trying to find pictures. These guys aren't having much luck in their application.

https://www.hydro.org/document/shaft-coatings-and-turbine-corrosion/

 

[EliasS]

Thanks for your comments Tugboat. Composite repairs probaly work better for dynamic applications due to higher mechanical strength than only resin or elastomeric type liquid-applied ones. It is interesting to see that you design your application thinking on the repair stage.

Steve, thanks for the information.
Indeed, the wrap coating I am looking at seems to be a type of "light" version of wrapping non-metallic sleeves for corrosion repairs.
A first approach that I am thinking of is that it would probably be OK for the splash-zone application if it can be proven resistant to at least the same qualification requirements of NACE TM0404,or equivalent tests considering the different products covered by the standard.

Regards,
EliasS.

 

[TugboatEng]

This is what ABS/NIST says about splash zone wrapping.

"In the splash zone, just above and below the water line, good corrosion prevention practice is characterized by minimizing the amount of structure in the water surface plane, and wrapping structural elements that pierce the water line with barrier materials such as Monel, Tideguard, and Splashstron. Properly applied, these materials are very effective at preventing corrosion in what is considered the area of a platform with the highest potential for metal loss. Nonstructural elements such as risers, sumps, well conductors, boat landings, etc. in the splash zone may be wrapped with barrier materials or protected with multi layered coating systems. All systems in the splash zone fall prey to the mechanical damage of wave action and boat impact."

https://www.google.com/url?sa=t&sou...FjAEegQIBRAB&usg=AOvVaw3-VIpKzAutbagALn7OFIPM

 

[SJones]

Generally, the preference will be for sprayed coatings mainly because the specifications are established and trained, qualified applicators are readily available. In addition, productivity is likely to be higher.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.