CP & Coating

[CoCoE]

I have seen a Company has specified MIO pigmented epoxy coating of DFT 500 microns for underground piping, which need to be cathodically protected.

I would like to know the opinion /advise on the below things.

1. How good MIO epoxy can withstand the abrasion/pressure in buried condition without damaging?
2. Is it having good resistance, or is it partially conductive? All of you know that this gonna affect my CP design if the coating resistance is not good.
3. Has somebody got CD test (Cathodic Disbondment) done in this kind of coating and got a good result?

I am very much confused ! Please advise.

Cococa

 

[Ron]

MIO pigmented coatings are generally electrically conductive and thermally conductive.

The abrasion resistance and vulnerability to impact damage (brittleness) depends on the epoxy formulation.

500 microns is good but barely in the "high build" area of coating thickness. You might want to consider a bit more thickness...say 625 or 750 microns.

One of the benefits of MIO pigmentation is that it makes for a "high build" coating....meaning it creates a greater DFT than an unpigmented or conventionally pigmented coating. Why not take advantage of this and achieve a higher build of the coating to increase its protection. This is important because any breach of the coating becomes a potential corrosion concentration cell that will locally exacerbate corrosion.